http://www.mdpi.com/journal/marinedrugs Latest open access articles published in Mar. Drugs at http://www.mdpi.com/journal/marinedrugs http://www.mdpi.com/1660-3397/11/6/1800 A new antitumor and antioxidant peptide (H3) was isolated from Arca subcrenata Lischke using ion exchange and hydrophobic column chromatography. The purity of H3 was over 99.3% in reversed phase-high performance liquid chromatography (RP-HPLC) and the molecular weight was determined to be 20,491.0 Da by electrospray-ionization mass spectrometry (ESI-MS/MS). The isoelectric point of H3 was measured to be 6.65 by isoelectric focusing-polyacrylamide gel electrophoresis. Partial amino acid sequence of this peptide was determined as ISMEDVEESRKNGMHSIDVNH DGKHRAYWADNTYLM-KCMDLPYDVLDTGGKDRSSDKNTDLVDLFELDMVPDRK NNECMNMIMDVIDTN-TAARPYYCSLDVNHDGAGLSMEDVEEDK via MALDI-TOF/ TOF-MS and de novo sequencing. The in vitro antitumor activity of H3 was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The result indicated that H3 exhibited significant antiproliferative activity against HeLa, HepG2 and HT-29 cell lines with IC50 values of 10.8, 10.1 and 10.5 μg/mL. The scavenging percentage of H3 at 8 mg/mL to 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radicals were 56.8% and 47.5%, respectively. Marine Drugs 2013-05-24 11 6 Article 10.3390/md11061800 1800 1814 1660-3397 2013-05-24 doi: 10.3390/md11061800 Lili Chen Liyan Song Tingfei Li Jianhua Zhu Jian Xu Qin Zheng Rongmin Yu http://www.mdpi.com/1660-3397/11/6/1783 This study was conducted to evaluate the promoting effect of Ishige sinicola, an alga native to Jeju Island, Korea, on hair growth. When vibrissa follicles were cultured in the presence of I. sinicola extract for 21 days, I. sinicola extract increased hair-fiber length. After topical application of I. sinicola extract onto the back of C57BL/6 mice, anagen progression of the hair shaft was induced. The I. sinicola extract significantly inhibited the activity of 5α-reductase. Treatment of immortalized vibrissa dermal papilla cells (DPCs) with I. sinicola extract resulted in increase of cell proliferation, which was accompanied by the increase of phospho-GSK3β level, β-catenin, Cyclin E and CDK2, whereas p27kip1 was down-regulated. In particular, octaphlorethol A, an isolated component from the I. sinicola extract, inhibited the activity of 5α-reductase and increased the proliferation of DPCs. These results suggest that I. sinicola extract and octaphlorethol A, a principal of I. sinicola, have the potential to treat alopecia via the proliferation of DPCs followed by the activation of β-catenin pathway, and the 5α-reductase inhibition. Marine Drugs 2013-05-24 11 6 Article 10.3390/md11061783 1783 1799 1660-3397 2013-05-24 doi: 10.3390/md11061783 Jung-Il Kang Eun-JI Kim Min-Kyoung Kim You-Jin Jeon Sung-Myung kang Young-Sang Koh Eun-Sook Yoo Hee-Kyoung Kang http://www.mdpi.com/1660-3397/11/6/1763 Exposure of cells to the diarrhetic shellfish poison, okadaic acid, leads to a dramatic reorganization of cytoskeletal architecture and loss of cell-cell contact. When cells are exposed to high concentrations of okadaic acid (100–500 nM), the morphological rearrangement is followed by apoptotic cell death. Okadaic acid inhibits the broad acting Ser/Thr protein phosphatases 1 and 2A, which results in hyperphosphorylation of a large number of proteins. Some of these hyperphosphorylated proteins are most likely key players in the reorganization of the cell morphology induced by okadaic acid. We wanted to identify these phosphoproteins and searched for them in the cellular lipid rafts, which have been found to contain proteins that regulate cytoskeletal dynamics and cell adhesion. By using stable isotope labeling by amino acids in cell culture cells treated with okadaic acid (400 nM) could be combined with control cells before the isolation of lipid rafts. Protein phosphorylation events and translocations induced by okadaic acid were identified by mass spectrometry. Okadaic acid was shown to regulate the phosphorylation status and location of proteins associated with the actin cytoskeleton, microtubules and cell adhesion structures. A large number of these okadaic acid-regulated proteins have previously also been shown to be similarly regulated prior to cell proliferation and migration. Our results suggest that okadaic acid activates general cell signaling pathways that induce breakdown of the cortical actin cytoskeleton and cell detachment. Marine Drugs 2013-05-24 11 6 Article 10.3390/md11061763 1763 1782 1660-3397 2013-05-24 doi: 10.3390/md11061763 Jill Opsahl Sonja Ljostveit Therese Solstad Kristin Risa Peter Roepstorff Kari Fladmark http://www.mdpi.com/1660-3397/11/5/1728 On a global scale, jellyfish populations in coastal marine ecosystems exhibit increasing trends of abundance. High-density outbreaks may directly or indirectly affect human economical and recreational activities, as well as public health. As the interest in biology of marine jellyfish grows, a number of jellyfish metabolites with healthy potential, such as anticancer or antioxidant activities, is increasingly reported. In this study, the Mediterranean “fried egg jellyfish” Cotylorhiza tuberculata (Macri, 1778) has been targeted in the search forputative valuable bioactive compounds. A medusa extract was obtained, fractionated, characterized by HPLC, GC-MS and SDS-PAGE and assayed for its biological activity on breast cancer cells (MCF-7) and human epidermal keratinocytes (HEKa). The composition of the jellyfish extract included photosynthetic pigments, valuable ω-3 and ω-6 fatty acids, and polypeptides derived either from jellyfish tissues and their algal symbionts. Extract fractions showed antioxidant activity and the ability to affect cell viability and intercellular communication mediated by gap junctions (GJIC) differentially in MCF-7and HEKa cells. A significantly higher cytotoxicity and GJIC enhancement in MCF-7 compared to HEKa cells was recorded. A putative action mechanism for the anticancer bioactivity through the modulation of GJIC has been hypothesized and its nutraceutical and pharmaceutical potential was discussed. Marine Drugs 2013-05-22 11 5 Article 10.3390/md11051728 1728 1762 1660-3397 2013-05-22 doi: 10.3390/md11051728 Antonella Leone Raffaella Lecci Miriana Durante Stefano Piraino http://www.mdpi.com/1660-3397/11/5/1718 Eighteen polyketides (1–18) including six citrinin derivatives, two phenol derivatives, one cyclopentenone, two naphthol derivatives, and seven tetralone derivatives were isolated from the culture broth of a marine-derived fungal strain Xylariaceae sp. SCSGAF0086. Five of these compounds (1, 2, 8, 9, and 10) were new, and their structures were determined by spectroscopic methods. Compounds 4, 6, 7, and 17 showed enzyme-inhibitory activities towards several tested enzymes, and 6 and 7 showed strong antifouling activity against Bugula neritina larvae settlement. This is the first time that the antifouling and enzyme-inhibitory activities of these compounds has been reported. Marine Drugs 2013-05-21 11 5 Article 10.3390/md11051718 1718 1727 1660-3397 2013-05-21 doi: 10.3390/md11051718 Xu-Hua Nong Zhi-Hui Zheng Xiao-Yong Zhang Xin-Hua Lu Shu-Hua Qi http://www.mdpi.com/1660-3397/11/5/1693 Since the late 1980s, a large number of depsipeptides that contain a new topography, referred to as “head-to-side-chain” cyclodepsipeptides, have been isolated and characterized. These peptides present a unique structural arrangement that comprises a macrocyclic region closed through an ester bond between the C-terminus and a β-hydroxyl group, and terminated with a polyketide moiety or a more simple branched aliphatic acid. This structural pattern, the presence of unique and complex residues, and relevant bioactivity are the main features shared by all the members of this new class of depsipeptides, which are reviewed herein. Marine Drugs 2013-05-21 11 5 Review 10.3390/md11051693 1693 1717 1660-3397 2013-05-21 doi: 10.3390/md11051693 Marta Pelay-Gimeno Judit Tulla-Puche Fernando Albericio http://www.mdpi.com/1660-3397/11/5/1677 Plitidepsin is an antitumor drug of marine origin currently in Phase III clinical trials in multiple myeloma. In cultured cells, plitidepsin induces cell cycle arrest or an acute apoptotic process in which sustained activation of c-Jun N-terminal kinase (JNK) plays a crucial role. With a view to optimizing clinical use of plitidepsin, we have therefore evaluated the possibility of using JNK activation as an in vivo biomarker of response. In this study, we show that administration of a single plitidepsin dose to mice xenografted with human cancer cells does indeed lead to increased phosphorylation of JNK in tumors at 4 to 12 h. By contrast, no changes were found in other in vitro plitidepsin targets such as the levels of phosphorylated-ERK, -p38MAPK or the protein p27KIP1. Interestingly, plitidepsin also increased JNK phosphorylation in spleens from xenografted mice showing similar kinetics to those seen in tumors, thereby suggesting that normal tissues might be useful for predicting drug activity. Furthermore, plitidepsin administration to rats at plasma concentrations comparable to those achievable in patients also increased JNK phosphorylation in peripheral mononuclear blood cells. These findings suggest that changes in JNK activity provide a reliable biomarker for plitidepsin activity and this could be useful for designing clinical trials and maximizing the efficacy of plitidepsin. Marine Drugs 2013-05-21 11 5 Article 10.3390/md11051677 1677 1692 1660-3397 2013-05-21 doi: 10.3390/md11051677 María Muñoz-Alonso Enrique Álvarez María Guillén-Navarro Marina Pollán Pablo Avilés Carlos Galmarini Alberto Muñoz http://www.mdpi.com/1660-3397/11/5/1669 In 2011, a Diarrhetic Shellfish Poisoning (DSP) outbreak occurred in British Columbia (BC), Canada that was associated with cooked mussel consumption. This is the first reported DSP outbreak in BC. Investigation of ill individuals, traceback of product and laboratory testing for toxins were used in this investigation. Sixty-two illnesses were reported. Public health and food safety investigation identified a common food source and harvest area. Public health and regulatory agencies took actions to recall product and notify the public. Shellfish monitoring program changes were implemented after the outbreak. Improved response and understanding of toxin production will improve management of future DSP outbreaks. Marine Drugs 2013-05-21 11 5 Article 10.3390/md11051669 1669 1676 1660-3397 2013-05-21 doi: 10.3390/md11051669 Marsha Taylor Lorraine McIntyre Mark Ritson Jason Stone Roni Bronson Olga Bitzikos Wade Rourke Eleni Galanis Outbreak Team http://www.mdpi.com/1660-3397/11/5/1656 Protein phosphorylation is involved in the regulation of a wide variety of physiological processes and is the result of a balance between protein kinase and phosphatase activities. Biologically active marine derived compounds have been shown to represent an interesting source of novel compounds that could modify that balance. Among them, the marine toxin and tumor promoter, okadaic acid (OA), has been shown as an inhibitor of two of the main cytosolic, broad-specificity protein phosphatases, PP1 and PP2A, thus providing an excellent cell-permeable probe for examining the role of protein phosphorylation, and PP1 and PP2A in particular, in any physiological or pathological process. In the present work, we review the use of okadaic acid to identify specific phosphoepitopes mainly in proteins relevant for neurodegeneration. We will specifically highlight those cases of highly dynamic phosphorylation-dephosphorylation events and the ability of OA to block the high turnover phosphorylation, thus allowing the detection of modified residues that could be otherwise difficult to identify. Finally, its effect on tau hyperhosphorylation and its relevance in neurodegenerative pathologies such as Alzheimer’s disease and related dementia will be discussed. Marine Drugs 2013-05-21 11 5 Review 10.3390/md11051656 1656 1668 1660-3397 2013-05-21 doi: 10.3390/md11051656 Miguel Medina Jesús Avila Nieves Villanueva http://www.mdpi.com/1660-3397/11/5/1644 Astaxanthin is a novel carotenoid nutraceutical occurring in many crustaceans and red yeasts. It has exhibited various biological activities including prevention or amelioration of cardiovascular disease, gastric ulcer, hypertension, and diabetic nephropathy. In this study, ultrasound-assisted extraction was developed for the effective extraction of astaxanthin from Haematococcus pluvialis. Some parameters such as extraction solvent, liquid-to-solid ratio, extraction temperature, and extraction time were optimized by single-factor experiment and response surface methodology. The optimal extraction conditions were 48.0% ethanol in ethyl acetate, the liquid-to-solid ratio was 20:1 (mL/g), and extraction for 16.0 min at 41.1 °C under ultrasound irradiation of 200 W. Under optimal conditions, the yield of astaxanthin was 27.58 ± 0.40 mg/g. The results obtained are beneficial for the full utilization of Haematococcus pluvialis, which also indicated that ultrasound-assisted extraction is a very useful method for extracting astaxanthin from marine life. Marine Drugs 2013-05-21 11 5 Article 10.3390/md11051644 1644 1655 1660-3397 2013-05-21 doi: 10.3390/md11051644 Tang-Bin Zou Qing Jia Hua-Wen Li Chang-Xiu Wang Hong-Fu Wu http://www.mdpi.com/1660-3397/11/5/1602 Meroterpenes are widely distributed among marine organisms; they are particularly abundant within brown algae, but other important sources include microorganisms and invertebrates. In the present review the structures and bioactivities of meroterpenes from marine invertebrates, mainly sponges and tunicates, are summarized. More than 300 molecules, often complex and with unique skeletons originating from intra- and inter-molecular cyclizations, and/or rearrangements, are illustrated. The reported syntheses are mentioned. The issue of a potential microbial link to their biosynthesis is also shortly outlined. Marine Drugs 2013-05-17 11 5 Review 10.3390/md11051602 1602 1643 1660-3397 2013-05-17 doi: 10.3390/md11051602 Marialuisa Menna Concetta Imperatore Filomena D'Aniello Anna Aiello http://www.mdpi.com/1660-3397/11/5/1583 Laboratory experiments were designed to study the toxin content and profile of the Alexandrium catenella strain ACT03 (isolated from Thau Lagoon, French Mediterranean) in response to abiotic environmental factors under nutrient-replete conditions. This dinoflagellate can produce various paralytic shellfish toxins with concentrations ranging from 2.9 to 50.3 fmol/cell. The toxin profile was characterized by carbamate toxins (GTX3, GTX4 and GTX5) and N-sulfocarbamoyl toxins (C1, C2, C3 and C4). C2 dominated at 12–18 °C, but only for salinities ranging from 10 to 25 psu, whereas GTX5 became dominant at temperatures ranging from 21 to 30 °C at almost all salinities. There was no significant variation in the cellular toxin amount from 18 °C to 27 °C for salinities ranging between 30 and 40 psu. At salinities of 10 to 25 psu, the toxin concentrations always remained below 20 fmol/cell. Toxin content was stable for irradiance ranging from 10 to 70 μmol photons/m2/s then slightly increased. Overall, the toxin profile was more stable than the toxin content (fmol/cell), except for temperature and/or salinity values different from those recorded during Alexandrium blooms in Thau Lagoon. Marine Drugs 2013-05-15 11 5 Article 10.3390/md11051583 1583 1601 1660-3397 2013-05-15 doi: 10.3390/md11051583 Mohamed Laabir Yves Collos Estelle Masseret Daniel Grzebyk Eric Abadie Véronique Savar Manoella Sibat Zouher Amzil http://www.mdpi.com/1660-3397/11/5/1565 Eighteen new 11,20-epoxy-3Z,5E-dien briaranes, gemmacolides AA–AR (1–18), were isolated together with three known analogs, dichotellides F (19) and I (20), and juncenolide C (21), from the South China Sea gorgonian Dichotella gemmacea. The structures of the compounds were elucidated by detailed spectroscopic analysis and comparison with reported data. The absolute configuration was determined based on the ECD experiment. In the in vitro bioassay, compounds 1–3, 5, 6, 8–12, and 14–19 exhibited different levels of growth inhibition activity against A549 and MG63 cell lines. Preliminary structure-activity analysis suggests that 12-O-isovalerate may increase the activity whereas 13- or 14-O-isovalerate may decrease the activity. Contribution of substitutions at C-2 and C-16 remains uncertain. Marine Drugs 2013-05-15 11 5 Article 10.3390/md11051565 1565 1582 1660-3397 2013-05-15 doi: 10.3390/md11051565 Cui Li Mei Jiang Ming-Ping La Tie-Jun Li Hua Tang Peng Sun Bao-Shu Liu Yang-Hua Yi Zhiyong Liu Wen Zhang http://www.mdpi.com/1660-3397/11/5/1553 In this work, we investigated the spasmolytic effect of caulerpine, a bisindole alkaloid isolated from marine algae of the Caulerpa genus, on guinea pig ileum. Our findings indicated that caulerpine inhibited phasic contractions induced by carbachol (IC50 = 7.0 ± 1.9 × 10−5 M), histamine (IC50 = 1.3 ± 0.3 × 10−4 M) and serotonin (IC50 = 8.0 ± 1.4 × 10−5 M) in a non-selective manner. Furthermore, caulerpine concentration-dependently inhibited serotonin-induced cumulative contractions (pD′2 = 4.48 ± 0.08), shifting the curves to the right with Emax reduction and slope of 2.44 ± 0.21, suggesting a noncompetitive antagonism pseudo-irreversible. The alkaloid also relaxed the ileum pre-contracted by KCl (EC50 = 9.0 ± 0.9 × 10−5 M) and carbachol (EC50 = 4.6 ± 0.7 × 10−5 M) in a concentration-dependent manner. This effect was probably due to inhibition of Ca2+ influx through voltage-gated calcium channels (CaV), since caulerpine slightly inhibited the CaCl2-induced contractions in depolarizing medium without Ca2+, shifting the curves to the right and with Emax reduction. According to these results, the spasmolytic effect of caulerpine on guinea pig ileum seems to involve inhibition of Ca2+ influx through CaV. However, other mechanisms are not discarded. Marine Drugs 2013-05-13 11 5 Article 10.3390/md11051553 1553 1564 1660-3397 2013-05-13 doi: 10.3390/md11051553 Luiz Cavalcante-Silva Ana de Carvalho Correia José Barbosa-Filho Bagnólia da Silva Bárbara de Oliveira Santos Daysianne de Lira Jéssica Sousa George de Miranda Fabiana de Andrade Cavalcante Magna Alexandre-Moreira http://www.mdpi.com/1660-3397/11/5/1534 This present study deals with synthesis, characterization and antibacterial activity of cross-linked chitosan-glutaraldehyde. Results from this study indicated that cross-linked chitosan-glutaraldehyde markedly inhibited the growth of antibiotic-resistant Burkholderia cepacia complex regardless of bacterial species and incubation time while bacterial growth was unaffected by solid chitosan. Furthermore, high temperature treated cross-linked chitosan-glutaraldehyde showed strong antibacterial activity against the selected strain 0901 although the inhibitory effects varied with different temperatures. In addition, physical-chemical and structural characterization revealed that the cross-linking of chitosan with glutaraldehyde resulted in a rougher surface morphology, a characteristic Fourier transform infrared (FTIR) band at 1559 cm−1, a specific X-ray diffraction peak centered at 2θ = 15°, a lower contents of carbon, hydrogen and nitrogen, and a higher stability of glucose units compared to chitosan based on scanning electron microscopic observation, FTIR spectra, X-ray diffraction pattern, as well as elemental and thermo gravimetric analysis. Overall, this study indicated that cross-linked chitosan-glutaraldehyde is promising to be developed as a new antibacterial drug. Marine Drugs 2013-05-13 11 5 Article 10.3390/md11051534 1534 1552 1660-3397 2013-05-13 doi: 10.3390/md11051534 Bin Li Chang-Lin Shan Qing Zhou Yuan Fang Yang-Li Wang Fei Xu Li-Rong Han Muhammad Ibrahim Long-Biao Guo Guan-Lin Xie Guo-Chang Sun http://www.mdpi.com/1660-3397/11/5/1524 Two new oxazole/thiazole derivatives, named tetroazolemycins A (1) and B (2), have been isolated from the acetone extract of the mycelium of Streptomyces olivaceus FXJ8.012 derived from deep-sea water, together with three known compounds, spoxazomicins A–C (3–5), isolated from the fermentation supernatant. The planar structure and relative configuration of tetroazolemycins were elucidated by a combination of spectroscopic analyses, including 1D- and 2D-NMR techniques, and showed to be new pyochelin-type antibiotics. Both compounds showed metal ion-binding activity and their Zn2+ complexes exhibited weak activity against pathogenic bacteria Klebsiella pneumoniae. Marine Drugs 2013-05-10 11 5 Article 10.3390/md11051524 1524 1533 1660-3397 2013-05-10 doi: 10.3390/md11051524 Ning Liu Fei Shang Lijun Xi Ying Huang http://www.mdpi.com/1660-3397/11/5/1506 Interesting biological activities have been found for numerous marine compounds. In fact, screening of phylogenetically diverse marine microorganisms from extreme environments revealed to be a rational approach for the discovery of novel molecules with relevant bioactivities for industries such as pharmaceutical and cosmeceutical. Nevertheless, marine sources deliverables are still far from the expectations and new extreme sources of microbes should be explored. In this work, a marine prokaryotic collection from four Mid-Atlantic Ridge (MAR) deep sea hydrothermal vents near the Azores Islands, Portugal, was created, characterized and tested for its photoprotective capacity. Within 246 isolates, a polyphasic approach, using chemotaxonomic and molecular typing methods, identified 23-related clusters of phenetically similar isolates with high indexes of diversity. Interestingly, 16S rRNA gene sequencing suggested the presence of 43% new prokaryotic species. A sub-set of 139 isolates of the prokaryotic collection was selected for biotechnological exploitation with 484 bacterial extracts prepared in a sustainable upscalling manner. 22% of the extracts showed an industrially relevant photoprotective activity, with two extracts, belonging to new strains of the species Shewanella algae and Vibrio fluvialis, uniquely showing UV-A, UV-B and UV-C protective capacity. This clearly demonstrates the high potential of the bacteria MAR vents collection in natural product synthesis with market applications. Marine Drugs 2013-05-10 11 5 Article 10.3390/md11051506 1506 1523 1660-3397 2013-05-10 doi: 10.3390/md11051506 Ana Martins Tania Tenreiro Gonçalo Andrade Mário Gadanho Sandra Chaves Marta Abrantes Patrícia Calado Rogério Tenreiro Helena Vieira http://www.mdpi.com/1660-3397/11/5/1492 Active peptide from shark liver (APSL) is a cytokine from Chiloscyllium plagiosum that can stimulate liver regeneration and protects the pancreas. To study the effect of orally administered recombinant APSL (rAPSL) on an animal model of type 2 diabetes mellitus, the APSL gene was cloned, and APSL was expressed in Bombyx mori N cells (BmN cells), silkworm larvae and silkworm pupae using the silkworm baculovirus expression vector system (BEVS). It was demonstrated that rAPSL was able to significantly reduce the blood glucose level in mice with type 2 diabetes induced by streptozotocin. The analysis of paraffin sections of mouse pancreatic tissues revealed that rAPSL could effectively protect mouse islets from streptozotocin-induced lesions. Compared with the powder prepared from normal silkworm pupae, the powder prepared from pupae expressing rAPSL exhibited greater protective effects, and these results suggest that rAPSL has potential uses as an oral drug for the treatment of diabetes mellitus in the future. Marine Drugs 2013-05-07 11 5 Article 10.3390/md11051492 1492 1505 1660-3397 2013-05-07 doi: 10.3390/md11051492 Yunlong Liu Ying Chen Jianqing Chen Wenping Zhang Qing Sheng Jian Chen Wei Yu Zuoming Nie Yaozhou Zhang Wutong Wu Lisha Wang Inthrani Indran Jun Li Lian Qian Zhengbing Lv http://www.mdpi.com/1660-3397/11/5/1490 It has been brought to our attention that the Figure 1 (page 2177) in our published paper [1] has some errors, we would like to change it to the following one: Marine Drugs 2013-05-07 11 5 Correction 10.3390/md11051490 1490 1491 1660-3397 2013-05-07 doi: 10.3390/md11051490 Gi-Young Kim Wun-Jae Kim Yung Choi http://www.mdpi.com/1660-3397/11/5/1477 The chemical investigation of the recently described Mediterranean Homoscleromorpha sponge Oscarella balibaloi revealed an original family of five closely related glucosylated sesterterpenes 1–4, named balibalosides. Their structure elucidation was mainly inferred from NMR and HRMS data analyses. Balibalosides differ by the pattern of acetyl substitutions on the three sugar residues linked to the same aglycone sesterterpenoid core. From a biosynthetic perspective, these compounds may represent intermediates in the pathways leading to more complex sesterterpenes frequently found in Dictyoceratida, a sponge Order belonging to Demospongiae, a clade which is phylogenetically distinct from the Homoscleromorpha. While steroid and triterpenoid saponins were already well known from marine sponges, balibalosides are the first examples of glycosilated sesterterpenes. Marine Drugs 2013-05-06 11 5 Article 10.3390/md11051477 1477 1489 1660-3397 2013-05-06 doi: 10.3390/md11051477 Coralie Audoin Dominique Bonhomme Julijana Ivanisevic Mercedes Cruz Bastien Cautain Maria Monteiro Fernando Reyes Laurent Rios Thierry Perez Olivier Thomas http://www.mdpi.com/1660-3397/11/5/1456 Three different fucoidan fractions were isolated and purified from the brown alga, Sargassum mcclurei. The SmF1 and SmF2 fucoidans are sulfated heteropolysaccharides that contain fucose, galactose, mannose, xylose and glucose. The SmF3 fucoidan is highly sulfated (35%) galactofucan, and the main chain of the polysaccharide contains a →3)-α-l-Fucp(2,4SO3−)-(1→3)-α-l-Fucp(2,4SO3−)-(1→ motif with 1,4-linked 3-sulfated α-l-Fucp inserts and 6-linked galactose on reducing end. Possible branching points include the 1,2,6- or 1,3,6-linked galactose and/or 1,3,4-linked fucose residues that could be glycosylated with terminal β-d-Galp residues or chains of alternating sulfated 1,3-linked α-l-Fucp and 1,4-linked β-d-Galp residues, which have been identified in galactofucans for the first time. Both α-l-Fucp and β-d-Galp residues are sulfated at C-2 and/or C-4 (and some C-6 of β-d-Galp) and potentially the C-3 of terminal β-d-Galp, 1,4-linked β-d-Galp and 1,4-linked α-l-Fucp residues. All fucoidans fractions were less cytotoxic and displayed colony formation inhibition in colon cancer DLD-1 cells. Therefore, these fucoidan fractions are potential antitumor agents. Marine Drugs 2013-05-06 11 5 Article 10.3390/md11051456 1456 1476 1660-3397 2013-05-06 doi: 10.3390/md11051456 Pham Thinh Roza Menshova Svetlana Ermakova Stanislav Anastyuk Bui Ly Tatiana Zvyagintseva http://www.mdpi.com/1660-3397/11/5/1440 The neuritogenic and neuroprotective activities of six starfish polar steroids, asterosaponin Р1, (25S)-5α-cholestane-3β,4β,6α,7α,8,15α,16β,26-octaol, and (25S)-5α-cholestane-3β,6α,7α,8,15α,16β,26-heptaol (1–3) from the starfish Patiria pectinifera and distolasterosides D1–D3 (4–6) from the starfish Distolasterias nipon were analyzed using the mouse neuroblastoma (NB) C-1300 cell line and an organotypic rat hippocampal slice culture (OHSC). All of these compounds enhanced neurite outgrowth in NB cells. Dose-dependent responses to compounds 1–3 were observed within the concentration range of 10–100 nM, and dose-dependent responses to glycosides 4–6 were observed at concentrations of 1–50 nM. All the tested substances exhibited notable synergistic effects with trace amounts of nerve growth factor (NGF, 1 ng/mL) or brain-derived neurotrophic factor (BDNF, 0.1 ng/mL). Using NB cells and OHSCs, it was shown for the first time that starfish steroids 1–6 act as neuroprotectors against oxygen-glucose deprivation (OGD) by increasing the number of surviving cells. Altogether, these results suggest that neurotrophin-like neuritogenic and neuroprotective activities are most likely common properties of starfish polyhydroxysteroids and the related glycosides, although the magnitude of the effect depended on the particular compound structure. Marine Drugs 2013-05-03 11 5 Article 10.3390/md11051440 1440 1455 1660-3397 2013-05-03 doi: 10.3390/md11051440 Natalia Palyanova Tatyana Pankova Marina Starostina Alla Kicha Natalia Ivanchina Valentin Stonik http://www.mdpi.com/1660-3397/11/5/1427 Eudistomin Y class compounds are a series of β-carbolines which was originally isolated from a marine turnicate or ascidian near the South Korea Sea. These compounds contain bromo-substituted groups, which is one of the typical characters of marine natural products. We report herein the chemical synthesis and biological evaluation of seven new β-carboline-based metabolites, Eudistomins Y1–Y7, and their hydroxyl-methylated phenyl derivatives. Using bromo-substituted tryptamines and bromo-substituted phenylglyoxals as the key intermediates, Eudistomins Y1–Y7 and their derivatives were synthesized via the acid-catalyzed Pictet-Spengler reaction and fully characterized by 1H- and 13C-NMR and mass spectroscopy. Biological studies revealed that all of the compounds showed moderate growth inhibitory activity against breast carcinoma cell line MDA-231 with IC50 of 15–63 μM and the inhibitory activities of hydroxyl-methylated phenyl products were higher than that of the corresponding natural products Eudistomins Y1–Y7. Marine Drugs 2013-04-29 11 5 Article 10.3390/md11051427 1427 1439 1660-3397 2013-04-29 doi: 10.3390/md11051427 Huijuan Jin Puyong Zhang Krikor Bijian Sumei Ren Shengbiao Wan Moulay Alaoui-Jamali Tao Jiang http://www.mdpi.com/1660-3397/11/4/1409 Protein tyrosine phosphatase 1B (PTP1B) plays a major role in the negative regulation of insulin signaling, and is thus considered as an attractive therapeutic target for the treatment of diabetes. Bioassay-guided investigation of the methylethylketone extract of marine-derived fungus Penicillium sp. JF-55 cultures afforded a new PTP1B inhibitory styrylpyrone-type metabolite named penstyrylpyrone (1), and two known metabolites, anhydrofulvic acid (2) and citromycetin (3). Compounds 1 and 2 inhibited PTP1B activity in a dose-dependent manner, and kinetic analyses of PTP1B inhibition suggested that these compounds inhibited PTP1B activity in a competitive manner. In an effort to gain more biological potential of the isolated compounds, the anti-inflammatory effects of compounds 1–3 were also evaluated. Among the tested compounds, only compound 1 inhibited the production of NO and PGE2, due to the inhibition of the expression of iNOS and COX-2. Penstyrylpyrone (1) also reduced TNF-α and IL-1β production, and these anti-inflammatory effects were shown to be correlated with the suppression of the phosphorylation and degradation of IκB-α, NF-κB nuclear translocation, and NF-κB DNA binding activity. In addition, using inhibitor tin protoporphyrin (SnPP), an inhibitor of HO-1, it was verified that the inhibitory effects of penstyrylpyrone (1) on the pro-inflammatory mediators and NF-κB DNA binding activity were associated with the HO-1 expression. Therefore, these results suggest that penstyrylpyrone (1) suppresses PTP1B activity, as well as the production of pro-inflammatory mediators via NF-κB pathway, through expression of anti-inflammatory HO-1. Marine Drugs 2013-04-23 11 4 Article 10.3390/md11041409 1409 1426 1660-3397 2013-04-23 doi: 10.3390/md11041409 Dong-Sung Lee Jae-Hyuk Jang Wonmin Ko Kyoung-Su Kim Jae Sohn Myeong-Suk Kang Jong Ahn Youn-Chul Kim Hyuncheol Oh http://www.mdpi.com/1660-3397/11/4/1399 A new chloro-trinoreremophilane sesquiterpene 1, three new chlorinated eremophilane sesquiterpenes 2–4, together with a known compound, eremofortine C (5), were isolated from an Antarctic deep-sea derived fungus, Penicillium sp. PR19N-1. Structures were established using IR, HRMS, 1D and 2D NMR techniques. In addition, the plausible metabolic network of these isolated products is proposed. Compound 1 showed moderate cytotoxic activity against HL-60 and A549 cancer cell lines. Marine Drugs 2013-04-23 11 4 Article 10.3390/md11041399 1399 1408 1660-3397 2013-04-23 doi: 10.3390/md11041399 Guangwei Wu Aiqun Lin Qianqun Gu Tianjiao Zhu Dehai Li http://www.mdpi.com/1660-3397/11/4/1370 The predatory marine gastropod Dicathais orbita has been the subject of a significant amount of biological and chemical research over the past five decades. Natural products research on D. orbita includes the isolation and identification of brominated indoles and choline esters as precursors of Tyrian purple, as well as the synthesis of structural analogues, bioactivity testing, biodistributional and biosynthetic studies. Here I also report on how well these compounds conform to Lipinski’s rule of five for druglikeness and their predicted receptor binding and enzyme inhibitor activity. The composition of mycosporine-like amino acids, fatty acids and sterols has also been described in the egg masses of D. orbita. The combination of bioactive compounds produced by D. orbita is of interest for further studies in chemical ecology, as well as for future nutraceutical development. Biological insights into the life history of this species, as well as ongoing research on the gene expression, microbial symbionts and biosynthetic capabilities, should facilitate sustainable production of the bioactive compounds. Knowledge of the phylogeny of D. orbita provides an excellent platform for novel research into the evolution of brominated secondary metabolites in marine molluscs. The range of polarities in the brominated indoles produced by D. orbita has also provided an effective model system used to develop a new method for biodistributional studies. The well characterized suite of chemical reactions that generate Tyrian purple, coupled with an in depth knowledge of the ecology, anatomy and genetics of D. orbita provide a good foundation for ongoing natural products research. Marine Drugs 2013-04-23 11 4 Review 10.3390/md11041370 1370 1398 1660-3397 2013-04-23 doi: 10.3390/md11041370 Kirsten Benkendorff http://www.mdpi.com/1660-3397/11/4/1351 Biopolymers produced by marine organisms can offer useful tools for regenerative medicine. Particularly, HE800 exopolysaccharide (HE800 EPS) secreted by a deep-sea hydrothermal bacterium displays an interesting glycosaminoglycan-like feature resembling hyaluronan. Previous studies demonstrated its effectiveness to enhance in vivo bone regeneration and to support osteoblastic cell metabolism in culture. Thus, in order to assess the usefulness of this high-molecular weight polymer in tissue engineering and tissue repair, in vitro reconstructed connective tissues containing HE800 EPS were performed. We showed that this polysaccharide promotes both collagen structuring and extracellular matrix settle by dermal fibroblasts. Furthermore, from the native HE800 EPS, a low-molecular weight sulfated derivative (HE800 DROS) displaying chemical analogy with heparan-sulfate, was designed. Thus, it was demonstrated that HE800 DROS mimics some properties of heparan-sulfate, such as promotion of fibroblast proliferation and inhibition of matrix metalloproteinase (MMP) secretion. Therefore, we suggest that the HE800EPS family can be considered as an innovative biotechnological source of glycosaminoglycan-like compounds useful to design biomaterials and drugs for tissue engineering and repair. Marine Drugs 2013-04-23 11 4 Article 10.3390/md11041351 1351 1369 1660-3397 2013-04-23 doi: 10.3390/md11041351 Karim Senni Farida Gueniche Sylvie Changotade Dominique Septier Corinne Sinquin Jacqueline Ratiskol Didier Lutomski Gaston Godeau Jean Guezennec Sylvia Colliec-Jouault http://www.mdpi.com/1660-3397/11/4/1336 Dendritic cells (DCs) are antigen presenting cells, which can present antigens to T-cells and play an important role in linking innate and adaptive immunity. DC maturation can be induced by many stimuli, including pro-inflammatory cytokines and bacterial products, such as lipopolysaccharides (LPS). Here, we examined the immunomodulatory effects of marine cembrane compounds, (9E,13E)-5-acetoxy-6-hydroxy-9,13-dimethyl-3- methylene-3,3a,4,5,6,7,8,11,12,14a-decahydro-2H-cyclotrideca[b]furan-2-one (1), (9E,13E)- 5-acetoxy-6-acetyl-9,13-dimethyl-3-methylene-3,3a,4,5,6,7,8,11,12,14a-decahydro-2H-cyclotrideca[b]furan-2-one (2), lobocrassin B (3), (−)14-deoxycrassin (4), cembranolide B (5) and 13-acetoxysarcocrassolide (6) isolated from a soft coral, Lobophytum crassum, on mouse bone marrow-derived dendritic cells (BMDCs). The results revealed that cembrane-type diterpenoids, especially lobocrassin B, effectively inhibited LPS-induced BMDC activation by inhibiting the production of TNF-α. Pre-treatment of BMDCs with Lobocrassin B for 1 h is essential to prohibit the following activation induced by various toll-like receptor (TLR) agonists, such as LPS, zymosan, lipoteichoic acid (LTA) and Pam2CSK4. Inhibition of NF-κB nuclear translocation by lobocrassin B, which is a key transcription factor for cytokine production in TLR signaling, was evident as assayed by high-content image analysis. Lobocrassin B attenuated DC maturation and endocytosis as the expression levels of MHC class II and the co-stimulatory molecules were downregulated, which may affect the function of DCs to initiate the T-cell responses. Thus, lobocrassin B may have the potential in treatment of immune dysregulated diseases in the future. Marine Drugs 2013-04-22 11 4 Article 10.3390/md11041336 1336 1350 1660-3397 2013-04-22 doi: 10.3390/md11041336 Ching-Yen Lin Mei-Chin Lu Jui-Hsin Su Ching-Liang Chu David Shiuan Ching-Feng Weng Ping-Jyun Sung Kao-Jean Huang http://www.mdpi.com/1660-3397/11/4/1316 Marine cyanobacteria, notably those from tropical regions, are a rich source of bioactive secondary metabolites. Tropical marine cyanobacteria often grow to high densities in the environment, allowing direct isolation of many secondary metabolites from field-collected material. However, in temperate environments culturing is usually required to produce enough biomass for investigations of their chemical constituents. In this work, we cultured a selection of novel and diverse cyanobacteria isolated from the Portuguese coast, and tested their organic extracts in a series of ecologically-relevant bioassays. The majority of the extracts showed activity in at least one of the bioassays, all of which were run in very small scale. Phylogenetically related isolates exhibited different activity profiles, highlighting the value of microdiversity for bioprospection studies. Furthermore, LC-MS analyses of selected active extracts suggested the presence of previously unidentified secondary metabolites. Overall, the screening strategy employed here, in which previously untapped cyanobacterial diversity was combined with multiple bioassays, proved to be a successful strategy and allowed the selection of several strains for further investigations based on their bioactivity profiles. Marine Drugs 2013-04-22 11 4 Article 10.3390/md11041316 1316 1335 1660-3397 2013-04-22 doi: 10.3390/md11041316 Pedro Leão Vitor Ramos Patrício Gonçalves Flávia Viana Olga Lage William Gerwick Vitor Vasconcelos http://www.mdpi.com/1660-3397/11/4/1304 The marine sponge, Axinyssa djiferi, collected on mangrove tree roots in Senegal, was investigated for glycolipids. A mixture containing new glycosphingolipids, named axidjiferoside-A, -B and -C, accounted for 0.07% of sponge biomass (dry weight) and for 2.16% of total lipids. It showed a significant antimalarial activity, with a 50% inhibitory concentration (IC50) of 0.53 ± 0.2 μM against a chloroquine-resistant strain of Plasmodium falciparum. They were identified as homologous β-galactopyranosylceramides composed of 2-amino-(6E)-octadec-6-en-1,3,4-triol, and the major one, axidjiferoside-A (around 60%), contained 2-hydroxytetracosanoic acid. Cytotoxicity was studied in vitro on human cancer cell lines (multiple myeloma, colorectal adenocarcinoma, glioblastoma and two lung cancer NSCLC-N6 and A549). Results of this investigation showed that axidjiferosides are of interest, because they proved a good antiplasmodial activity, with only a low cytotoxicity against various human cell lines and no significant antitrypanosomal and antileishmanial activity. Thus, it seems that galactosylceramides with a β anomeric configuration may be suitable in searching for new antimalarial drugs. Marine Drugs 2013-04-17 11 4 Article 10.3390/md11041304 1304 1315 1660-3397 2013-04-17 doi: 10.3390/md11041304 Fereshteh Farokhi Philippe Grellier Monique Clément Christos Roussakis Philippe Loiseau Emilie Genin-Seward Jean-Michel Kornprobst Gilles Barnathan Gaëtane Wielgosz-Collin http://www.mdpi.com/1660-3397/11/4/1300 The following paragraphs are reproduced from the publisher’s website [1]. There is a great deal of consumer interest in natural bioactive substances due to their health benefits. Offering the potential to provide valuable nutraceuticals and functional food ingredients, marine-derived compounds are an abundant source of nutritionally and pharmacologically active agents, with both chemical diversity and complexity. Functional ingredients derived from marine algae, invertebrates, vertebrates, and microorganisms can help fill the need for novel bioactives to treat chronic conditions such as cancer, microbial infections, and inflammatory processes. Marine Drugs 2013-04-17 11 4 New Book Received 10.3390/md11041300 1300 1303 1660-3397 2013-04-17 doi: 10.3390/md11041300 Shu-Kun Lin http://www.mdpi.com/1660-3397/11/4/1288 Secondary metabolites contained in marine organisms disclose diverse pharmacological activities, due to their intrinsic ability to recognize bio-macromolecules, which alter their expression and modulate their function. Thus, the identification of the cellular pathways affected by marine natural products is crucial to provide important functional information concerning their mechanism of action at the molecular level. Perthamide C, a marine sponge metabolite isolated from the polar extracts of Theonella swinhoei and endowed with a broad and interesting anti-inflammatory profile, was found in a previous study to specifically interact with heat shock protein-90 and glucose regulated protein-94, also disclosing the ability to reduce cisplatin-mediated apoptosis. In this paper, we evaluated the effect of this compound on the whole proteome of murine macrophages cells by two-dimensional DIGE proteomics. Thirty-three spots were found to be altered in expression by at least 1.6-fold and 29 proteins were identified by LC ESI-Q/TOF-MS. These proteins are involved in different processes, such as metabolism, structural stability, protein folding assistance and gene expression. Among them, perthamide C modulates the expression of several chaperones implicated in the folding of proteins correlated to apoptosis, such as Hsp90 and T-complexes, and in this context our data shed more light on the cellular effects and pathways altered by this marine cyclo-peptide. Marine Drugs 2013-04-17 11 4 Article 10.3390/md11041288 1288 1299 1660-3397 2013-04-17 doi: 10.3390/md11041288 Annalisa Vilasi Maria Monti Alessandra Tosco Simona Marino Luigi Margarucci Raffaele Riccio Agostino Casapullo http://www.mdpi.com/1660-3397/11/4/1271 Demosponges possess a skeleton made of a composite material with various organic constituents and/or siliceous spicules. Chitin is an integral part of the skeleton of different sponges of the order Verongida. Moreover, sponges of the order Verongida, such as Aplysina cavernicola or Ianthella basta, are well-known for the biosynthesis of brominated tyrosine derivates, characteristic bioactive natural products. It has been unknown so far whether these compounds are exclusively present in the cellular matrix or whether they may also be incorporated into the chitin-based skeletons. In the present study, we therefore examined the skeletons of A. cavernicola and I. basta with respect to the presence of bromotyrosine metabolites. The chitin-based-skeletons isolated from these sponges indeed contain significant amounts of brominated compounds, which are not easily extractable from the skeletons by common solvents, such as MeOH, as shown by HPLC analyses in combination with NMR and IR spectroscopic measurements. Quantitative potentiometric analyses confirm that the skeleton-associated bromine mainly withstands the MeOH-based extraction. This observation suggests that the respective, but yet unidentified, brominated compounds are strongly bound to the sponge skeletons, possibly by covalent bonding. Moreover, gene fragments of halogenases suggested to be responsible for the incorporation of bromine into organic molecules could be amplified from DNA isolated from sponge samples enriched for sponge-associated bacteria. Marine Drugs 2013-04-17 11 4 Article 10.3390/md11041271 1271 1287 1660-3397 2013-04-17 doi: 10.3390/md11041271 Kurt Kunze Hendrik Niemann Susanne Ueberlein Renate Schulze Hermann Ehrlich Eike Brunner Peter Proksch Karl-Heinz Pée http://www.mdpi.com/1660-3397/11/4/1256 A growing market for novel antioxidants obtained from non-expensive sources justifies educated screening of microalgae for their potential antioxidant features. Characterization of the antioxidant profile of 18 species of cyanobacteria (prokaryotic microalgae) and 23 species of (eukaryotic) microalgae is accordingly reported in this paper. The total antioxidant capacity, accounted for by both water- and lipid-soluble antioxidants, was evaluated by the (radical cation) ABTS method. For complementary characterization of cell extracts, a deoxyribose assay was carried out, as well as a bacteriophage P22/Salmonella-mediated approach. The microalga Scenedesmus obliquus strain M2-1 exhibited the highest (p > 0.05) total antioxidant capacity (149 ± 47 AAU) of intracellular extracts. Its scavenger activity correlated well with its protective effects against DNA oxidative damage induced by copper(II)-ascorbic acid; and against decay in bacteriophage infection capacity induced by H2O2. Finally, performance of an Ames test revealed no mutagenic effects of the said extract. Marine Drugs 2013-04-17 11 4 Article 10.3390/md11041256 1256 1270 1660-3397 2013-04-17 doi: 10.3390/md11041256 A. Guedes Maria Gião Rui Seabra A. Ferreira Paula Tamagnini Pedro Moradas-Ferreira F. Malcata http://www.mdpi.com/1660-3397/11/4/1235 Chemical analyses and mass spectrometry were used to study the structure of the lipopolysaccharide (LPS) isolated from Aeromonas bestiarum strain K296, serotype O18. ESI-MS revealed that the most abundant A. bestiarum LPS glycoforms have a hexa-acylated or tetra-acylated lipid A with conserved architecture of the backbone, consisting of a 1,4′-bisphosphorylated β-(1→6)-linked d-GlcN disaccharide with an AraN residue as a non-stoichiometric substituent and a core oligosaccharide composed of Kdo1Hep6Hex1HexN1P1. 1D and 2D NMR spectroscopy revealed that the O-specific polysaccharide (OPS) of A. bestiarum K296 consists of a branched tetrasaccharide repeating unit containing two 6-deoxy-l-talose (6dTalp), one Manp and one GalpNAc residues; thus, it is similar to that of the OPS of A. hydrophila AH-3 (serotype O34) in both the sugar composition and the glycosylation pattern. Moreover, 3-substituted 6dTalp was 2-O-acetylated and additional O-acetyl groups were identified at O-2 and O-4 (or O-3) positions of the terminal 6dTalp. Western blots with polyclonal rabbit sera showed that serotypes O18 and O34 share some epitopes in the LPS. The very weak reaction of the anti-O34 serum with the O-deacylated LPS of A. bestiarum K296 might have been due to the different O-acetylation pattern of the terminal 6dTalp. The latter suggestion was further confirmed by NMR. Marine Drugs 2013-04-17 11 4 Article 10.3390/md11041235 1235 1255 1660-3397 2013-04-17 doi: 10.3390/md11041235 Anna Turska-Szewczuk Buko Lindner Iwona Komaniecka Alicja Kozinska Agnieszka Pekala Adam Choma Otto Holst http://www.mdpi.com/1660-3397/11/4/1221 Stephanolepis hispidus is one of the most common filefish species in Brazil. Its skin is traditionally used as a complementary treatment for inflammatory disorders. However, there are very few studies on chemical and pharmacological properties using the skin of this fish. This study was undertaken in order to investigate the effect of aqueous crude extract of S. hispidus skin (SAE) in different nociception models. Here, we report that intraperitoneal administration of SAE inhibited the abdominal constrictions induced by acetic acid in mice. In addition to the effect seen in the abdominal constriction model, SAE was also able to inhibit the hyperalgesia induced by carrageenan and prostaglandin E2 (PGE2) in mice. This potent antinociceptive effect was observed in the hot plate model too, but not in tail-flick test. Naloxone, an opioid receptor antagonist, was able to block the antinociceptive effect of SAE in the abdominal constriction and hot plate models. In addition, SAE did not present cytotoxic or genotoxic effect in human peripheral blood cells. Our results suggest that aqueous crude extract from S. hispidus skin has antinociceptive activity in close relationship with the partial activation of opioid receptors in the nervous system. Moreover, aqueous crude extract from S. hispidus skin does not present toxicity and is therefore endowed with the potential for pharmacological control of pain. Marine Drugs 2013-04-10 11 4 Article 10.3390/md11041221 1221 1234 1660-3397 2013-04-10 doi: 10.3390/md11041221 Vinicius Carvalho Lohengrin Fernandes Taline Conde Helena Zamith Ronald Silva Andrea Surrage Valber Frutuoso Hugo Castro-Faria-Neto Fabio Amendoeira http://www.mdpi.com/1660-3397/11/4/1203 A vital ingredient for engineering bone tissue, in the culture dish, is the use of recombinant matrix and growth proteins to help accelerate the growth of cultivated tissues into clinically acceptable quantities. The skeletal organic matrices of calcifying marine invertebrates are an untouched potential source of such growth inducing proteins. They have the advantage of being ready-made and retain the native state of the original protein. Striking evidence shows that skeleton building bone morphogenic protein-2/4 (BMP) and transforming growth factor beta (TGF-β) exist within various marine invertebrates such as, corals. Best practice mariculture and the latest innovations in long-term marine invertebrate cell cultivation can be implemented to ensure that these proteins are produced sustainably and supplied continuously. This also guarantees that coral reef habitats are not damaged during the collection of specimens. Potential proteins for bone repair, either extracted from the skeleton or derived from cultivated tissues, can be identified, evaluated and retrieved using chromatography, cell assays and proteomic methods. Due to the current evidence for bone matrix protein analogues in marine invertebrates, together with the methods established for their production and retrieval there is a genuine prospect that they can be used to regenerate living bone for potential clinical use. Marine Drugs 2013-04-10 11 4 Review 10.3390/md11041203 1203 1220 1660-3397 2013-04-10 doi: 10.3390/md11041203 David Green Matthew Padula Jerran Santos Joshua Chou Bruce Milthorpe Besim Ben-Nissan http://www.mdpi.com/1660-3397/11/4/1188 A novel peptide, RsXXIVA, was isolated from the venom duct of Conus regularis, a worm-hunting species collected in the Sea of Cortez, México. Its primary structure was determined by mass spectrometry and confirmed by automated Edman degradation. This conotoxin contains 40 amino acids and exhibits a novel arrangement of eight cysteine residues (C-C-C-C-CC-CC). Surprisingly, two loops of the novel peptide are highly identical to the amino acids sequence of ω-MVIIA. The total length and disulfide pairing of both peptides are quite different, although the two most important residues for the described function of ω-MVIIA (Lys2 and Tyr13) are also present in the peptide reported here. Electrophysiological analysis using superior cervical ganglion (SCG) neurons indicates that RsXXIVA inhibits CaV2.2 channel current in a dose-dependent manner with an EC50 of 2.8 μM, whose effect is partially reversed after washing. Furthermore, RsXXIVA was tested in hot-plate assays to measure the potential anti-nociceptive effect to an acute thermal stimulus, showing an analgesic effect in acute thermal pain at 30 and 45 min post-injection. Also, the toxin shows an anti-nociceptive effect in a formalin chronic pain test. However, the low affinity for CaV2.2 suggests that the primary target of the peptide could be different from that of ω-MVIIA. Marine Drugs 2013-04-08 11 4 Article 10.3390/md11041188 1188 1202 1660-3397 2013-04-08 doi: 10.3390/md11041188 Johanna Bernáldez Sergio Román-González Oscar Martínez Samanta Jiménez Oscar Vivas Isabel Arenas Gerardo Corzo Roberto Arreguín David García Lourival Possani Alexei Licea http://www.mdpi.com/1660-3397/11/4/1173 Marine xylanases are rather less studied compared to terrestrial xylanases. In this study, a new xylanase gene, xynB, was cloned from the marine bacterium, Glaciecola mesophila KMM241, and expressed in Escherichia coli. xynB encodes a multi-domain xylanase XynB of glycoside hydrolase (GH) family 8. The recombinant XynB comprises an N-terminal domain (NTD) with unknown function and a catalytic domain, which is structurally novel among the characterized xylanases of GH family 8. XynB has the highest identity (38%) to rXyn8 among the characterized xylanases. The recombinant XynB showed maximal activity at pH 6–7 and 35 °C. It is thermolabile and salt-tolerant. XynB is an endo-xylanase that demands at least five sugar moieties for effective cleavage and to hydrolyze xylohexaose and xylopentaose into xylotetraose, xylotriose and xylobiose. NTD was expressed in Escherichia coli to analyze its function. The recombinant NTD exhibited a high binding ability to insoluble xylan and avicel and little binding ability to chitosan and chitin. Since the NTD shows no obvious homology to any known carbohydrate-binding module (CBM) sequence in public databases, XynB may contain a new type of CBM. Marine Drugs 2013-04-08 11 4 Article 10.3390/md11041173 1173 1187 1660-3397 2013-04-08 doi: 10.3390/md11041173 Bing Guo Ping-Yi Li Yong-Sheng Yue Hui-Lin Zhao Sheng Dong Xiao-Yan Song Cai-Yun Sun Wei-Xin Zhang Xiu-Lan Chen Xi-Ying Zhang Bai-Cheng Zhou Yu-Zhong Zhang http://www.mdpi.com/1660-3397/11/4/1162 Chemical examination of a South China Sea soft coral Lobophytum sp. led to the isolation of three new α-methylene-γ-lactone-containing cembranoids, (1R*,3R*, 4R*,14R*,7E,11E)-3,4-epoxycembra-7,11,15(17)-trien-16,14-olide (1), (1R*,7S*,14S*,3E, 11E)-7-hydroperoxycembra-3,8(19),11,15(17)-tetraen-16,14-olide (2), and (1R*,7S*,14S*, 3E,11E)-18-acetoxy-7-hydroperoxycembra-3,8(19),11,15(17)-tetraen-16,14-olide (3), along with eleven known analogues 4–14. The structures of the new compounds were elucidated through extensive spectroscopic analysis, including 1D and 2D NMR data. Compounds 1–3 exhibited moderate cytotoxic activity against the selected tumor cell lines. Moreover, 2 and 3 were found to be moderate inhibitors against the bacteria S. aureus and S. pneumoniae. Marine Drugs 2013-04-03 11 4 Article 10.3390/md11041162 1162 1172 1660-3397 2013-04-03 doi: 10.3390/md11041162 Min Zhao Jian Yin Wei Jiang Minshan Ma Xinxiang Lei Zheng Xiang Jianyong Dong Kexin Huang Pengcheng Yan http://www.mdpi.com/1660-3397/11/4/1152 Agents capable of inducing phase II enzymes such as quinone reductase 1 (QR1) are known to have the potential of mediating cancer chemopreventive activity. As part of a program to discover novel phase II enzyme-inducing molecules, we identified a marine-derived actinomycete strain (CNJ-878) that exhibited activity with cultured Hepa 1c1c7 cells. Based on this activity, a new macrolide, juvenimicin C (1), as well as 5-O-α-l-rhamnosyltylactone (2), were isolated from the culture broth of a Micromonospora sp. Compound 1 enhanced QR1 enzyme activity and glutathione levels by two-fold with CD values of 10.1 and 27.7 μM, respectively. In addition, glutathione reductase and glutathione peroxidase activities were elevated. This is the first reported member of the macrolide class of antibiotics found to mediate these responses. Marine Drugs 2013-04-03 11 4 Article 10.3390/md11041152 1152 1161 1660-3397 2013-04-03 doi: 10.3390/md11041152 Skylar Carlson Laura Marler Sang-Jip Nam Bernard Santarsiero John Pezzuto Brian Murphy http://www.mdpi.com/1660-3397/11/4/1140 Pancreatic cancer, the fourth leading cause of cancer death in the US, is highly resistant to all current chemotherapies, and its growth is facilitated by chronic inflammation. The majority of pro-inflammatory cytokines initiate signaling cascades that converge at the activation of the Nuclear Factor Kappa B (NFκB), a signal transduction molecule that promotes cell survival, proliferation and angiogenesis. In an effort to identify novel inhibitors of NFκB, the HBOI library of pure compounds was screened using a reporter cell line that produces luciferin under the transcriptional control of NFκB. Seven compounds were identified through this screen, but in the case of five of them, their reported mechanism of action made them unlikely to be specific NFκB inhibitors. Spongiatriol, a marine furanoditerpenoid that was first isolated in the 1970s, is shown here to inhibit NFκB transcriptional activity in a reporter cell line, to reduce levels of phosphorylated (active) NFκB in the AsPC-1 cell line, to have an IC50 for cytotoxicity in the low micromolar range against the AsPC-1, BxPC-3, MiaPaCa-2 and Panc-1 pancreatic cancer cell lines, and to induce moderate but significant apoptosis in both the AsPC-1 and the Panc-1 cell lines. Marine Drugs 2013-04-02 11 4 Article 10.3390/md11041140 1140 1151 1660-3397 2013-04-02 doi: 10.3390/md11041140 Esther Guzmán Michael Maher Alexis Temkin Tara Pitts Amy Wright http://www.mdpi.com/1660-3397/11/4/1126 We report on the screening of ethanolic extracts from 33 deep-sea Antarctic marine sponges for different biological activities. We monitored hemolysis, inhibition of acetylcholinesterase, cytotoxicity towards normal and transformed cells and growth inhibition of laboratory, commensal and clinically and ecologically relevant bacteria. The most prominent activities were associated with the extracts from sponges belonging to the genus Latrunculia, which show all of these activities. While most of these activities are associated to already known secondary metabolites, the extremely strong acetylcholinesterase inhibitory potential appears to be related to a compound unknown to date. Extracts from Tetilla leptoderma, Bathydorus cf. spinosus, Xestospongia sp., Rossella sp., Rossella cf. racovitzae and Halichondria osculum were hemolytic, with the last two also showing moderate cytotoxic potential. The antibacterial tests showed significantly greater activities of the extracts of these Antarctic sponges towards ecologically relevant bacteria from sea water and from Arctic ice. This indicates their ecological relevance for inhibition of bacterial microfouling. Marine Drugs 2013-04-02 11 4 Article 10.3390/md11041126 1126 1139 1660-3397 2013-04-02 doi: 10.3390/md11041126 Tom Turk Jerneja Avguštin Urška Batista Gašper Strugar Rok Kosmina Sandra Čivović Dorte Janussen Silke Kauferstein Dietrich Mebs Kristina Sepčić http://www.mdpi.com/1660-3397/11/4/1113 This study was aimed at developing a sensitive and selective HPLC method with postcolumn fluorescence derivatization for the detection of propylene glycol alginate sodium sulfate (PSS) in rat plasma. Plasma samples were prepared by a simple and fast ultrafiltration method. PSS was extracted from rat plasma with d-glucuronic acid as internal standard. Isocratic chromatographic separation was performed on a TSKgel G2500 PWxL column with the mobile phase of 0.1 M sodium sulfate at a flow rate of 0.5 mL/min. Analyte detection was achieved by fluorescence detection (FLD) at 250 nm (excitation) and 435 nm (emission) using guanidine hydrochloride as postcolumn derivatizing reagent in an alkaline medium at 120 °C. The calibration curve was linear over a concentration range of 1–500 μg/mL, and the lower limit of detection (LLOD) was found to be 250 ng/mL. This validated method was applied successfully to the pharmacokinetic study of PSS and PSS-loaded poly lactic-co-glycolic acid (PLGA) nanoparticles (PSS-NP) in rat plasma after a single intravenous (PSS only) and oral administration (PSS and PSS-NP). Significant differences in the main pharmacokinetic parameters of PSS and PSS-NP were observed. The relative bioavailability of PSS-NP was 190.10% compared with PSS which shows that PSS-NP can improve oral bioavailability. Marine Drugs 2013-04-02 11 4 Article 10.3390/md11041113 1113 1125 1660-3397 2013-04-02 doi: 10.3390/md11041113 Peng-Li Li Chun-Xia Li Yi-Ting Xue Hai-Hua Li Hong-Bing Liu Xiao-Xi He Guang-Li Yu Hua-Shi Guan http://www.mdpi.com/1660-3397/11/4/1104 Three new dolastane diterpenes (1–3) and five previously reported perhydroazulenes were isolated from the organic extracts of the brown alga Dilophus spiralis. The structure elucidation and the assignment of the relative configurations of the isolated natural products were based on extensive analyses of their spectroscopic data, whereas the absolute configuration of metabolite 2 was determined through its chemical conversion to a previously isolated compound of known configuration. Marine Drugs 2013-04-02 11 4 Article 10.3390/md11041104 1104 1112 1660-3397 2013-04-02 doi: 10.3390/md11041104 Efstathia Ioannou Constantinos Vagias Vassilios Roussis http://www.mdpi.com/1660-3397/11/4/1087 Hamacanthins, bis (indole) alkaloids, are found in a few marine sponges, including Spongosorites sp. Hamacanthins have been shown to possess cytotoxic, antibacterial and antifungal activities. However, the precise mechanism for the biological activities of hamacanthins has not yet been elucidated. In the present study, the anti-angiogenic effects of 6″-debromohamacanthin A (DBHA), an active component of isolated hamacanthins, were evaluated in cultured human umbilical vascular endothelial cells (HUVEC) and endothelial-like cells differentiated from mouse embryonic stem (mES) cells. DBHA significantly inhibited vascular endothelial growth factor (VEGF)-induced cell proliferation, migration and tube formation in the HUVEC. DBHA also suppressed the capillary-like structure formation and the expression of platelet endothelial cell adhesion molecule (PECAM), an endothelial biomarker, in mES cell-derived endothelial-like cells. To further understand the precise molecular mechanism of action, VEGF-mediated signaling pathways were analyzed in HUVEC cells and mES cell-derived endothelial-like cells. DBHA suppressed the VEGF-induced expression of MAPKs (p38, ERK and SAPK/JNK) and the PI3K/AKT/mTOR signaling pathway. In addition, DBHA inhibited microvessel sprouting in mES/EB-derived embryoid bodies. In an ex vivo model, DBHA also suppressed the microvessel sprouting of mouse aortic rings. The findings suggest for the first time that DBHA inhibits angiogenesis by targeting the vascular endothelial growth factor receptor 2 (VEGFR2)-mediated PI3K/AKT/mTOR signaling pathway in endothelial cells. Marine Drugs 2013-04-02 11 4 Article 10.3390/md11041087 1087 1103 1660-3397 2013-04-02 doi: 10.3390/md11041087 Gi Kim Oug Cheong Song Bae Jongheon Shin Sang Lee http://www.mdpi.com/1660-3397/11/4/1071 Forty four marine actinomycetes of the family Microccocaceae isolated from sponges collected primarily in Florida Keys (USA) were selected from our strain collection to be studied as new sources for the production of bioactive natural products. A 16S rRNA gene based phylogenetic analysis showed that the strains are members of the genera Kocuria and Micrococcus. To assess their biosynthetic potential, the strains were PCR screened for the presence of secondary metabolite genes encoding nonribosomal synthetase (NRPS) and polyketide synthases (PKS). A small extract collection of 528 crude extracts generated from nutritional microfermentation arrays was tested for the production of bioactive secondary metabolites against clinically relevant strains (Bacillus subtilis, methicillin-resistant Staphylococcus aureus (MRSA), Acinetobacter baumannii and Candida albicans). Three independent isolates were shown to produce a new anti-MRSA bioactive compound that was identified as kocurin, a new member of the thiazolyl peptide family of antibiotics emphasizing the role of this family as a prolific resource for novel drugs. Marine Drugs 2013-03-28 11 4 Article 10.3390/md11041071 1071 1086 1660-3397 2013-03-28 doi: 10.3390/md11041071 Sara Palomo Ignacio González Mercedes de la Cruz Jesús Martín José Tormo Matthew Anderson Russell Hill Francisca Vicente Fernando Reyes Olga Genilloud http://www.mdpi.com/1660-3397/11/4/1061 In continuation of our search for drug leads from Red Sea sponges we have investigated the ethyl acetate fraction of the organic extract of the Red Sea sponge Hyrtios species. Bioassay-directed fractionation of the active fraction resulted into the identification of three new alkaloids, hyrtioerectines D–F (1–3). Hyrtioerectines D–F belong to the rare marine alkaloids in which the indole and β-carboline fragments of the molecule are linked through C-3/C-3 of both moieties. The structures of the isolated compounds were established based on different spectroscopic data including UV, IR, 1D and 2D NMR (COSY, HSQC, and HMBC) and high-resolution mass spectral studies. The antimicrobial activity against several pathogens and the free radical scavenging activity of the compounds using DPPH reagent were evaluated. In addition, the growth inhibitory activity of the compounds against three cancer cell lines was also evaluated. Hyrtioerectines D–F (1–3) displayed variable antimicrobial, free radical scavenging and cancer growth inhibition activities. Generally, compounds 1 and 3 were more active than compound 2. Marine Drugs 2013-03-28 11 4 Article 10.3390/md11041061 1061 1070 1660-3397 2013-03-28 doi: 10.3390/md11041061 Diaa Youssef Lamiaa Shaala Hani Asfour http://www.mdpi.com/1660-3397/11/4/1050 A new antibacterial chlorinated benzophenone derivative, (±)-pestalachloride D (1), along with a related analog, (±)-pestalachloride C (2), was recently isolated from the marine-derived fungus Pestalotiopsis sp. isolated from a soft coral Sarcophyton sp. collected from Yongxing Island in the South China Sea. Both chiral HPLC analysis and single-crystal X-ray data indicated that 1 is a racemic mixture. Interestingly, 1 did not exhibit any effect in the zebrafish embryo teratogenicity assay, while 2 led to abnormal growth. The potential impact on zebrafish embryo growth is discussed based on their crystal structures. The main difference of crystal structures between 1 and 2 is that the six-member non-aromatic ring (O4, C10, C9, C8, C2′, and C3′) in 1 exhibits a distorted chair conformation, while 2 shows a distorted boat conformation. Moreover, compounds 1 and 2 both exhibited moderate antibacterial activity. Marine Drugs 2013-03-28 11 4 Article 10.3390/md11041050 1050 1060 1660-3397 2013-03-28 doi: 10.3390/md11041050 Mei-Yan Wei Dan Li Chang-Lun Shao Dong-Sheng Deng Chang-Yun Wang http://www.mdpi.com/1660-3397/11/4/1035 Five new diketopiperazine derivatives, (3Z,6E)-1-N-methyl-3-benzy lidene-6-(2S-methyl-3-hydroxypropylidene)piperazine-2,5-dione (1), (3Z,6E)-1-N-methyl-3-benzylidene-6-(2R-methyl-3-hydroxypropylidene)piperazine-2,5-dione (2), (3Z,6Z)-3- (4-hydroxybenzylidene)-6-isobutylidenepiperazine-2,5-dione (3), (3Z,6Z)-3-((1H-imidazol-5-yl)-methylene)-6-isobutylidenepiperazine-2,5-dione (4), and (3Z,6S)-3-benzylidene-6-(2S-but-2-yl)piperazine-2,5-dione (5), were isolated from the marine-derived actinomycete Streptomyces sp. FXJ7.328. The structures of 1–5 were determined by spectroscopic analysis, CD exciton chirality, the modified Mosher’s, Marfey’s and the C3 Marfey’s methods. Compound 3 showed modest antivirus activity against influenza A (H1N1) virus with an IC50 value of 41.5 ± 4.5 μM. In addition, compound 6 and 7 displayed potent anti-H1N1 activity with IC50 value of 28.9 ± 2.2 and 6.8 ± 1.5 μM, respectively. Due to the lack of corresponding data in the literature, the 13C NMR data of (3Z,6S)-3-benzylidene-6-isobutylpiperazine-2,5-dione (6) were also reported here for the first time. Marine Drugs 2013-03-28 11 4 Communication 10.3390/md11041035 1035 1049 1660-3397 2013-03-28 doi: 10.3390/md11041035 Pei Wang Lijun Xi Peipei Liu Yi Wang Wei Wang Ying Huang Weiming Zhu http://www.mdpi.com/1660-3397/11/4/1019 Objective: To investigate astaxanthin (ATX) neuroprotection, and its mechanism, on a 1-methyl-4-phenyl-pyridine ion (MPP+)-induced cell model of Parkinson’s disease. Methods: Mature, differentiated PC12 cells treated with MPP+ were used as an in vitro cell model. The MTT assay was used to investigate cell viability after ATX treatment, and western blot analysis was used to observe Sp1 (activated transcription factor 1) and NR1 (NMDA receptor subunit 1) protein expression, real-time PCR was used to monitor Sp1 and NR1 mRNA, and cell immunofluorescence was used to determine the location of Sp1 and NR1 protein and the nuclear translocation of Sp1. Results: PC12 cell viability was significantly reduced by MPP+ treatment. The expression of Sp1 and NR1 mRNA and protein were increased compared with the control (p < 0.01). Following co-treatment with ATX and MPP+, cell viability was significantly increased, and Sp1 and NR1 mRNA and protein were decreased, compared with the MPP+ groups (p < 0.01). In addition, mithracycin A protected PC12 cells from oxidative stress caused by MPP+ by specifically inhibiting the expression of Sp1. Moreover, cell immunofluorescence revealed that ATX could suppress Sp1 nuclear transfer. Conclusion: ATX inhibited oxidative stress induced by MPP+ in PC12 cells, via the SP1/NR1 signaling pathway. Marine Drugs 2013-03-28 11 4 Article 10.3390/md11041019 1019 1034 1660-3397 2013-03-28 doi: 10.3390/md11041019 Qinyong Ye Xiaodong Zhang Bixia Huang Yuangui Zhu Xiaochun Chen http://www.mdpi.com/1660-3397/11/4/991 Marine neurotoxins are natural products produced by phytoplankton and select species of invertebrates and fish. These compounds interact with voltage-gated sodium, potassium and calcium channels and modulate the flux of these ions into various cell types. This review provides a summary of marine neurotoxins, including their structures, molecular targets and pharmacologies. Saxitoxin and its derivatives, collectively referred to as paralytic shellfish toxins (PSTs), are unique among neurotoxins in that they are found in both marine and freshwater environments by organisms inhabiting two kingdoms of life. Prokaryotic cyanobacteria are responsible for PST production in freshwater systems, while eukaryotic dinoflagellates are the main producers in marine waters. Bioaccumulation by filter-feeding bivalves and fish and subsequent transfer through the food web results in the potentially fatal human illnesses, paralytic shellfish poisoning and saxitoxin pufferfish poisoning. These illnesses are a result of saxitoxin’s ability to bind to the voltage-gated sodium channel, blocking the passage of nerve impulses and leading to death via respiratory paralysis. Recent advances in saxitoxin research are discussed, including the molecular biology of toxin synthesis, new protein targets, association with metal-binding motifs and methods of detection. The eco-evolutionary role(s) PSTs may serve for phytoplankton species that produce them are also discussed. Marine Drugs 2013-03-27 11 4 Review 10.3390/md11040991 991 1018 1660-3397 2013-03-27 doi: 10.3390/md11040991 Kathleen Cusick Gary Sayler http://www.mdpi.com/1660-3397/11/4/975 Shellfish waste components contain significant levels of high quality protein and are therefore a potential source for biofunctional high-value peptides. The feasibility of applying a pilot scale enzymatic hydrolysis process to whole Mytilus edulis and, by fractionation, recover hydrolysates presenting a biological activity of interest, was evaluated. Fractions were tested on four immortalized cancerous cell lines: A549, BT549, HCT15 and PC3. The 50 kDa fraction, enriched in peptides, presented anti-proliferative activity with all cell lines and results suggest a bioactive molecule synergy within the fraction. At a protein concentration of 44 µg/mL, the 50 kDa fraction induced a mortality of 90% for PC3, 89% for A549, 85% for HCT15 and of 81% for BT549 cell lines. At the low protein concentration of only 11 µg/mL the 50 kDa fraction still entails a cell mortality of 76% for A549 and 87% for PC3 cell lines. The 50 kDa fraction contains 56% of proteins, 3% of lipids and 6% of minerals on a dry weight basis and the lowest levels detected of taurine and methionine and highest levels of threonine, proline and glycine amino acids. The enzymatic hydrolysis process suggests that Mytilus edulis by-products should be viewed as high-valued products with strong potential as anti-proliferative agent and promising active ingredients in functional foods. Marine Drugs 2013-03-27 11 4 Article 10.3390/md11040975 975 990 1660-3397 2013-03-27 doi: 10.3390/md11040975 Lucie Beaulieu Jacinthe Thibodeau Claudie Bonnet Piotr Bryl Marie-Elise Carbonneau http://www.mdpi.com/1660-3397/11/3/960 Diabetic retinopathy is a common diabetic eye disease caused by changes in retinal ganglion cells (RGCs). It is an ocular manifestation of systemic disease, which affects up to 80% of all patients who have had diabetes for 10 years or more. The genetically diabetic db/db mouse, as a model of type-2 diabetes, shows diabetic retinopathy induced by apoptosis of RGCs. Astaxanthin is a carotenoid with powerful antioxidant properties that exists naturally in various plants, algae and seafood. Here, astaxanthin was shown to reduce the apoptosis of RGCs and improve the levels of oxidative stress markers, including superoxide anion, malondialdehyde (MDA, a marker of lipid peroxidation), 8-hydroxy-2-deoxyguanosine (8-OHdG, indicator of oxidative DNA damage) and MnSOD (manganese superoxide dismutase) activity in the retinal tissue of db/db mouse. In addition, astaxanthin attenuated hydrogen peroxide(H2O2)-induced apoptosis in the transformed rat retinal ganglion cell line RGC-5. Therefore, astaxanthin may be developed as an antioxidant drug to treat diabetic retinopathy. Marine Drugs 2013-03-21 11 3 Article 10.3390/md11030960 960 974 1660-3397 2013-03-21 doi: 10.3390/md11030960 Ling-Yan Dong Jie Jin Gao Lu Xiao-Li Kang http://www.mdpi.com/1660-3397/11/3/944 Elisidepsin (PM02734, Irvalec®) is a synthetic marine-derived cyclic peptide of the Kahalalide F family currently in phase II clinical development. Elisidepsin was shown to induce rapid oncosis in ErbB3-expressing cells. Other predictive factors of elisidepsin sensitivity remained unknown. A panel of 23 cancer cell lines of different origin was assessed for elisidepsin cytotoxicity and correlated with mutational state, mRNA and protein expression of selected genes. Elisidepsin showed potent and broad cytotoxic effects in our cancer cell line panel, being active at concentrations ranging from 0.4 to 2 μM that may be relevant for clinical settings. We have shown that elisidepsin is more active in cells harboring epithelial phenotype with high E-cadherin and low vimentin expression. In addition, high ErbB3 and Muc1 expression was correlated with sensitivity to elisidepsin, whereas the presence of KRAS activating mutations was associated with resistance. In DU-PM cells with acquired resistance to elisidepsin, ErbB3 expression was decreased, while Bcl2 was increased. DU-PM cells displayed higher sensitivity to ErbB1-inhibitors suggesting possible cross-talk of ErbB1 and ErbB3 signaling pathways. Combinations of elisidepsin with lapatinib and several chemotherapies including 5-FU and oxaliplatin resulted in synergistic effects that offer the potential of clinical use of elisidepsin in combination settings. Marine Drugs 2013-03-20 11 3 Article 10.3390/md11030944 944 959 1660-3397 2013-03-20 doi: 10.3390/md11030944 Maria Serova Armand de Gramont Ivan Bieche Maria Riveiro Carlos Galmarini Miguel Aracil José Jimeno Sandrine Faivre Eric Raymond http://www.mdpi.com/1660-3397/11/3/934 The sulfated polysaccharides from Solieria filiformis (Sf), Botryocladia occidentalis (Bo), Caulerpa racemosa (Cr) and Gracilaria caudata (Gc) were extracted and extensively purified. These compounds were then subjected to in vitro assays to evaluate the inhibition of these polysaccharides on the growth of Leishmania (L.) amazonensis promastigotes. Under the same assay conditions, only three of the four sulfated polysaccharides were active against L. amazonensis, and the polysaccharide purified from Cr was the most potent (EC50 value: 34.5 μg/mL). The polysaccharides derived from Bo and Sf demonstrated moderate anti-leishmanial activity (EC50 values of 63.7 μg/mL and 137.4 μg/mL). In addition, we also performed in vitro cytotoxic assays toward peritoneal macrophages and J774 macrophages. For the in vitro cytotoxicity assay employing J774 cells, all of the sulfated polysaccharides decreased cell survival, with CC50 values of 27.3 μg/mL, 49.3 μg/mL, 73.2 μg/mL, and 99.8 μg/mL for Bo, Cr, Gc, and Sf, respectively. However, none of the sulfated polysaccharides reduced the cell growth rate of the peritoneal macrophages. These results suggest that macroalgae contain compounds with various chemical properties that can control specific pathogens. According to our results, the assayed sulfated polysaccharides were able to modulate the growth rate and cell survival of Leishmania (L.) amazonensis promastigotes in in vitro assays, and these effects involved the interaction of the sulfated polysaccharides on the cell membrane of the parasites. Marine Drugs 2013-03-20 11 3 Article 10.3390/md11030934 934 943 1660-3397 2013-03-20 doi: 10.3390/md11030934 Camila Lehnhardt Pires Selma Rodrigues Daniel Bristot Henrique Gaeta Daniela de Oliveira Toyama Wladimir Lobo Farias Marcos Toyama http://www.mdpi.com/1660-3397/11/3/903 Angiogenesis inhibitors have been successfully used for cancer therapy in the clinic. Many marine-derived natural products and their analogues have been reported to show antiangiogenic activities. Compared with the drugs in the clinic, these agents display interesting characteristics, including diverse sources, unique chemical structures, special modes of action, and distinct activity and toxicity profiles. This review will first provide an overview of the current marine-derived angiogenesis inhibitors based on their primary targets and/or mechanisms of action. Then, the marine-derived antiangiogenic protein kinase inhibitors will be focused on. And finally, the clinical trials of the marine-derived antiangiogenic agents will be discussed, with special emphasis on their application potentials, problems and possible coping strategies in their future development as anticancer drugs. Marine Drugs 2013-03-15 11 3 Review 10.3390/md11030903 903 933 1660-3397 2013-03-15 doi: 10.3390/md11030903 Ying-Qing Wang Ze-Hong Miao http://www.mdpi.com/1660-3397/11/3/896 Mammalian Ste20-like kinases 1 and 2 (MST1 and MST2) are activated in NIH3T3 cells exposed to okadaic acid. The Hippo pathway is a newly emerging signaling that functions as a tumor suppressor. MST1 and MST2 work as core kinases of the Hippo pathway and their activities depend on the autophosphorylation, which is negatively regulated by protein phosphatase 2A (PP2A). Okadaic acid has been frequently used to enhance the phosphorylation of MST1 and MST2 and to trigger the activation of the Hippo pathway. However other components of the Hippo pathway could also be targets of okadaic acid. In this review we first briefly summarize the molecular architecture of the Hippo pathway for the reference of researchers outside the field. We explain how MST kinases are regulated by PP2A and how okadaic acid activates MST2. Thereafter we discuss which components of the Hippo pathway are candidate substrates of protein phosphatases and which points we need to consider in the usage of okadaic acid to study the Hippo pathway. Marine Drugs 2013-03-14 11 3 Review 10.3390/md11030896 896 902 1660-3397 2013-03-14 doi: 10.3390/md11030896 Yutaka Hata Shikshya Timalsina Sainawaer Maimaiti http://www.mdpi.com/1660-3397/11/3/881 Antibody molecules, and antibody fragments in particular, have enormous potential in the development of biosensors for marine monitoring. Conventional immobilisation approaches used in immunoassays typically yield unstable and mostly incorrectly oriented antibodies, however, resulting in reduced detection sensitivities for already low concentration analytes. The 2H12 anti-domoic acid scFv antibody fragment was engineered with cysteine-containing linkers of two different lengths, distal to the antigen binding pocket, for covalent and correctly oriented immobilisation of the scFvs on functionalised solid supports. The Escherichia coli-produced, cysteine-engineered scFvs dimerised in solution and demonstrated similar efficiencies of covalent immobilisation on maleimide-activated plates and minimal non-covalent attachment. The covalently attached scFvs exhibited negligible leaching from the support under acidic conditions that removed almost 50% of the adsorbed wildtype fragment, and IC50s for domoic acid of 270 and 297 ng/mL compared with 1126 and 1482 ng/mL, respectively, for their non-covalently adsorbed counterparts. The expression and immobilisation approach will facilitate the development of stable, reusable biosensors with increased stability and detection sensitivity for marine neurotoxins. Marine Drugs 2013-03-14 11 3 Article 10.3390/md11030881 881 895 1660-3397 2013-03-14 doi: 10.3390/md11030881 María Hortigüela J. Wall http://www.mdpi.com/1660-3397/11/3/870 The aim of the present study is to evaluate the protective effect of polysaccharide from the Brown Seaweed Sargassum graminifolium (SGP) on ethylene glycol-induced kidney damage and the mechanism of SGP-mediated protection. Mitochondrial lipid peroxidation, mitochondrial swelling, the activity of succinate dehydrogenase (SDH), ATPases and mitochondrial antioxidant enzymes was observed in hyperoxaluric rats. Administration of SGP (25, 100 and 400 mg·kg−1, intragastrically) increased the activities of antioxidant enzymes, SDH and Na+/K+-ATPases, Ca2+-ATPases, Mg2+-ATPases, also decreased mitochondrial lipid peroxidation and mitochondrial swelling. SGP exhibited a protective effect by improving antioxidant enzymes and restoring mitochondrial dysfunction in the kidney of hyperoxaluric rats. It may be used as a promising therapeutic agent to provide superior renal protection. Marine Drugs 2013-03-13 11 3 Article 10.3390/md11030870 870 880 1660-3397 2013-03-13 doi: 10.3390/md11030870 Chao-Yan Zhang Ting Kong Wen-Hui Wu Min-Bo Lan http://www.mdpi.com/1660-3397/11/3/848 Toxins from marine animals offer novel drug leads for treatment of diseases involving ion channels. Computational methods could be very helpful in this endeavour in several ways, e.g., (i) constructing accurate models of the channel-toxin complexes using docking and molecular dynamics (MD) simulations; (ii) determining the binding free energies of toxins from umbrella sampling MD simulations; (iii) predicting the effect of mutations from free energy MD simulations. Using these methods, one can design new analogs of toxins with improved affinity and selectivity properties. Here we present a review of the computational methods and discuss their applications to marine toxins targeting potassium and sodium channels. Detailed examples from the potassium channel toxins—ShK from sea anemone and κ-conotoxin PVIIA—are provided to demonstrate capabilities of the computational methods to give accurate descriptions of the channel-toxin complexes and the energetics of their binding. An example is also given from sodium channel toxins (μ-conotoxin GIIIA) to illustrate the differences between the toxin binding modes in potassium and sodium channels. Marine Drugs 2013-03-13 11 3 Review 10.3390/md11030848 848 869 1660-3397 2013-03-13 doi: 10.3390/md11030848 M. Rashid Somayeh Mahdavi Serdar Kuyucak http://www.mdpi.com/1660-3397/11/3/842 Chemical investigation of a Chinese collection of marine red alga Symphyocladia latiuscula yielded two new highly brominated phenols. The structures of the new compounds were elucidated by detailed spectroscopic analysis, including HRMS, 1D and 2D NMR and MS methods. Compounds 1 and 2 were evaluated for radical scavenging capability by 1,1-diphenyl-2-picrylhydrazuyl (DPPH) radical with the IC50 value of 14.5 and 20.5 μg/mL, respectively. Marine Drugs 2013-03-13 11 3 Article 10.3390/md11030842 842 847 1660-3397 2013-03-13 doi: 10.3390/md11030842 Xiuli Xu Liyuan Yin Lijie Gao Junhai Gao Junhui Chen Jingxi Li Fuhang Song http://www.mdpi.com/1660-3397/11/3/830 Okadaic Acid (OA) constitutes the main active principle in Diarrhetic Shellfish Poisoning (DSP) toxins produced during Harmful Algal Blooms (HABs), representing a serious threat for human consumers of edible shellfish. Furthermore, OA conveys critical deleterious effects for marine organisms due to its genotoxic potential. Many efforts have been dedicated to OA biomonitoring during the last three decades. However, it is only now with the current availability of detailed molecular information on DNA organization and the mechanisms involved in the maintenance of genome integrity, that a new arena starts opening up for the study of OA contamination. In the present work we address the links between OA genotoxicity and chromatin by combining Next Generation Sequencing (NGS) technologies and bioinformatics. To this end, we introduce CHROMEVALOAdb, a public database containing the chromatin-associated transcriptome of the mussel Mytilus galloprovincialis (a sentinel model organism) in response to OA exposure. This resource constitutes a leap forward for the development of chromatin-based biomarkers, paving the road towards the generation of powerful and sensitive tests for the detection and evaluation of the genotoxic effects of OA in coastal areas. Marine Drugs 2013-03-12 11 3 Article 10.3390/md11030830 830 841 1660-3397 2013-03-12 doi: 10.3390/md11030830 Victoria Suárez-Ulloa Juan Fernández-Tajes Vanessa Aguiar-Pulido Ciro Rivera-Casas Rodrigo González-Romero Juan Ausio Josefina Méndez Julián Dorado José Eirín-López http://www.mdpi.com/1660-3397/11/3/817 Seven new azalomycin F analogs (1–7) were isolated from the broth of mangrove Streptomyces sp. 211726, and respectively identified as 25-malonyl demalonylazalomycin F5a monoester (1), 23-valine demalonylazalomycin F5a ester (2), 23-(6-methyl)heptanoic acid demalonylazalomycins F3a ester (3), F4a ester (4) and F5a ester (5), 23-(9-methyl)decanoic acid demalonylazalomycin F4a ester (6) and 23-(10-methyl)undecanoic acid demalony lazalomycin F4a ester (7). Their structures were established by their spectroscopic data and by comparing with those of azalomycins F3a, F4a and F5a. Biological assays exhibited that 1–7 showed broad-spectrum antimicrobial and anti HCT-116 activities. Marine Drugs 2013-03-12 11 3 Article 10.3390/md11030817 817 829 1660-3397 2013-03-12 doi: 10.3390/md11030817 Ganjun Yuan Kui Hong Haipeng Lin Zhigang She Jia Li http://www.mdpi.com/1660-3397/11/3/800 Microbial studies of the Mediterranean sponge Tethya aurantium led to the isolation of the fungus Bartalinia robillardoides strain LF550. The strain produced a number of secondary metabolites belonging to the chloroazaphilones. This is the first report on the isolation of chloroazaphilones of a fungal strain belonging to the genus Bartalinia. Besides some known compounds (helicusin A (1) and deacetylsclerotiorin (2)), three new chloroazaphilones (helicusin E (3); isochromophilone X (4) and isochromophilone XI (5)) and one new pentaketide (bartanolide (6)) were isolated. The structure elucidations were based on spectroscopic analyses. All isolated compounds revealed different biological activity spectra against a test panel of four bacteria: three fungi; two tumor cell lines and two enzymes. Marine Drugs 2013-03-12 11 3 Article 10.3390/md11030800 800 816 1660-3397 2013-03-12 doi: 10.3390/md11030800 Nils Jansen Birgit Ohlendorf Arlette Erhard Torsten Bruhn Gerhard Bringmann Johannes Imhoff http://www.mdpi.com/1660-3397/11/3/788 Five new eunicellin-based diterpenoids, krempfielins E–I (1–5) and seven known compounds (6–12) were isolated from the organic extract of a Taiwanese soft coral Cladiella krempfi. The structures of the new metabolites were elucidated on the basis of extensive spectroscopic analysis. Metabolites 5, 6, 10 and 12 were shown to exhibit cytotoxicity against a limited panel of cancer cell lines. Furthermore, compounds 6 and 10 could potently inhibit the accumulation of the pro-inflammatory iNOS protein, and 6 and 12 could significantly reduce the expression of COX-2 protein in LPS-stimulated RAW264.7 macrophage cells. Marine Drugs 2013-03-12 11 3 Article 10.3390/md11030788 788 799 1660-3397 2013-03-12 doi: 10.3390/md11030788 Chi-Jen Tai Jui-Hsin Su Chiung-Yao Huang Ming-Shyan Huang Zhi-Hong Wen Chang-Feng Dai Jyh-Horng Sheu http://www.mdpi.com/1660-3397/11/3/775 Seven new polyoxygenated steroids (1–7) were isolated together with seven known analogues (8–14) from the South China Sea soft coral, Sarcophyton sp. The structures of the new compounds were identified on the basis of extensive spectroscopic analysis and comparison with reported data. All the steroids are characterized with 3β,5α,6β-hydroxy moiety, displaying carbon skeletons of cholestane, ergostane, gorgostane and 23,24-dimethyl cholestane. In the in vitro bioassay, metabolites exhibited different levels of antimicrobial activity against bacterial species Escherichia coli and Bacillus megaterium, and fungal species Microbotryum violaceum and Septoria tritici. No inhibition was detected towards microalga Chlorella fusca. Preliminary structure-activity analysis suggests that the 11α-acetoxy group may increase both antibacterial and antifungal activities. The terminal-double bond and the cyclopropane moiety at the side chain may also contribute to the bioactivity. Marine Drugs 2013-03-11 11 3 Article 10.3390/md11030775 775 787 1660-3397 2013-03-11 doi: 10.3390/md11030775 Zenglei Wang Hua Tang Pan Wang Wei Gong Mei Xue Hongwei Zhang Taofang Liu Baoshu Liu Yanghua Yi Wen Zhang http://www.mdpi.com/1660-3397/11/3/747 In the last decade, an increasing number of glycosaminoglycans (GAGs), chitin and chitosan applications have been reported. Their commercial demands have been extended to different markets, such as cosmetics, medicine, biotechnology, food and textiles. Marine wastes from fisheries and aquaculture are susceptible sources for polymers but optimized processes for their recovery and production must be developed to satisfy such necessities. In the present work, we have reviewed different alternatives reported in the literature to produce and purify chondroitin sulfate (CS), hyaluronic acid (HA) and chitin/chitosan (CH/CHs) with the aim of proposing environmentally friendly processes by combination of various microbial, chemical, enzymatic and membranes strategies and technologies. Marine Drugs 2013-03-11 11 3 Review 10.3390/md11030747 747 774 1660-3397 2013-03-11 doi: 10.3390/md11030747 José Vázquez Isabel Rodríguez-Amado María Montemayor Javier Fraguas María González Miguel Murado http://www.mdpi.com/1660-3397/11/3/718 Bone defects in human, caused by fractures/nonunions or trauma, gain increasing impact and have become a medical challenge in the present-day aging population. Frequently, those fractures require surgical intervention which ideally relies on autografts or suboptimally on allografts. Therefore, it is pressing and likewise challenging to develop bone substitution materials to heal bone defects. During the differentiation of osteoblasts from their mesenchymal progenitor/stem cells and of osteoclasts from their hemopoietic precursor cells, a lineage-specific release of growth factors and a trans-lineage homeostatic cross-talk via signaling molecules take place. Hence, the major hurdle is to fabricate a template that is functioning in a way mimicking the morphogenetic, inductive role(s) of the native extracellular matrix. In the last few years, two naturally occurring polymers that are produced by deep-sea sponges, the biogenic polyphosphate (bio-polyP) and biogenic silica (bio-silica) have also been identified as promoting morphogenetic on both osteoblasts and osteoclasts. These polymers elicit cytokines that affect bone mineralization (hydroxyapatite formation). In this manner, bio-silica and bio-polyP cause an increased release of BMP-2, the key mediator activating the anabolic arm of the hydroxyapatite forming cells, and of RANKL. In addition, bio-polyP inhibits the progression of the pre-osteoclasts to functionally active osteoclasts. Based on these findings, new bioinspired strategies for the fabrication of bone biomimetic templates have been developed applying 3D-printing techniques. Finally, a strategy is outlined by which these two morphogenetically active polymers might be used to develop a novel functionally active polymer. Marine Drugs 2013-03-08 11 3 Review 10.3390/md11030718 718 746 1660-3397 2013-03-08 doi: 10.3390/md11030718 Xiaohong Wang Heinz Schröder Qingling Feng Florian Draenert Werner Müller http://www.mdpi.com/1660-3397/11/3/700 Marine microbial natural products (MMNPs) have attracted increasing attention from microbiologists, taxonomists, ecologists, agronomists, chemists and evolutionary biologists during the last few decades. Numerous studies have indicated that diverse marine microbes appear to have the capacity to produce an impressive array of MMNPs exhibiting a wide variety of biological activities such as antimicrobial, anti-tumor, anti-inflammatory and anti-cardiovascular agents. Marine microorganisms represent an underexplored reservoir for the discovery of MMNPs with unique scaffolds and for exploitation in the pharmaceutical and agricultural industries. This review focuses on MMNPs discovery and development over the past decades, including innovative isolation and culture methods, strategies for discovering novel MMNPs via routine screenings, metagenomics, genomics, combinatorial biosynthesis, and synthetic biology. The potential problems and future directions for exploring MMNPs are also discussed. Marine Drugs 2013-03-08 11 3 Review 10.3390/md11030700 700 717 1660-3397 2013-03-08 doi: 10.3390/md11030700 Zhi-Qiang Xiong Jian-Feng Wang Yu-You Hao Yong Wang http://www.mdpi.com/1660-3397/11/3/680 Neuropathic pain afflicts a large percentage of the global population. This form of chronic, intractable pain arises when the peripheral or central nervous systems are damaged, either directly by lesion or indirectly through disease. The comorbidity of neuropathic pain with other diseases, including diabetes, cancer, and AIDS, contributes to a complex pathogenesis and symptom profile. Because most patients present with neuropathic pain refractory to current first-line therapeutics, pharmaceuticals with greater efficacy in pain management are highly desired. In this review we discuss the growing application of ω-conotoxins, small peptides isolated from Conus species, in the management of neuropathic pain. These toxins are synthesized by predatory cone snails as a component of paralytic venoms. The potency and selectivity with which ω-conotoxins inhibit their molecular targets, voltage-gated Ca2+ channels, is advantageous in the treatment of neuropathic pain states, in which Ca2+ channel activity is characteristically aberrant. Although ω-conotoxins demonstrate analgesic efficacy in animal models of neuropathic pain and in human clinical trials, there remains a critical need to improve the convenience of peptide drug delivery methods, and reduce the number and severity of adverse effects associated with ω-conotoxin-based therapies. Marine Drugs 2013-03-07 11 3 Review 10.3390/md11030680 680 699 1660-3397 2013-03-07 doi: 10.3390/md11030680 Heidi Hannon William Atchison http://www.mdpi.com/1660-3397/11/3/655 Sea anemone (Cnidaria, Anthozoa) venom is an important source of bioactive compounds used as tools to study the pharmacology and structure-function of voltage-gated K+ channels (KV). These neurotoxins can be divided into four different types, according to their structure and mode of action. In this work, for the first time, two toxins were purified from the venom of Bunodosoma caissarum population from Saint Peter and Saint Paul Archipelago, Brazil. Sequence alignment and phylogenetic analysis reveals that BcsTx1 and BcsTx2 are the newest members of the sea anemone type 1 potassium channel toxins. Their functional characterization was performed by means of a wide electrophysiological screening on 12 different subtypes of KV channels (KV1.1–KV1.6; KV2.1; KV3.1; KV4.2; KV4.3; hERG and Shaker IR). BcsTx1 shows a high affinity for rKv1.2 over rKv1.6, hKv1.3, Shaker IR and rKv1.1, while Bcstx2 potently blocked rKv1.6 over hKv1.3, rKv1.1, Shaker IR and rKv1.2. Furthermore, we also report for the first time a venom composition and biological activity comparison between two geographically distant populations of sea anemones. Marine Drugs 2013-03-06 11 3 Article 10.3390/md11030655 655 679 1660-3397 2013-03-06 doi: 10.3390/md11030655 Diego Orts Steve Peigneur Bruno Madio Juliana Cassoli Gabriela Montandon Adriano Pimenta José Bicudo José Freitas André Zaharenko Jan Tytgat http://www.mdpi.com/1660-3397/11/3/643 2,5-bis(3′-Indolyl)pyrroles, analogues of the marine alkaloid nortopsentin, were conveniently prepared through a three step procedure in good overall yields. Derivatives 1a and 1b exhibited concentration-dependent antitumor activity towards a panel of 42 human tumor cell lines with mean IC50 values of 1.54 μM and 0.67 μM, respectively. Investigating human tumor xenografts in an ex-vivo clonogenic assay revealed selective antitumor activity, whereas sensitive tumor models were scattered among various tumor histotypes. Marine Drugs 2013-03-01 11 3 Article 10.3390/md11030643 643 654 1660-3397 2013-03-01 doi: 10.3390/md11030643 Anna Carbone Barbara Parrino Paola Barraja Virginia Spanò Girolamo Cirrincione Patrizia Diana Armin Maier Gerhard Kelter Heinz-Herbert Fiebig http://www.mdpi.com/1660-3397/11/3/623 Conotoxins are small peptides present in the venom of cone snails. The snail uses this venom to paralyze and capture prey. The constituent conopeptides display a high level of chemical diversity and are of particular interest for scientists as tools employed in neurological studies and for drug development, because they target with exquisite specificity membrane receptors, transporters, and various ion channels in the nervous system. However, these peptides are known to contain a high frequency and variability of post-translational modifications—including sometimes O-glycosylation—which are of importance for biological activity. The potential application of specific conotoxins as neuropharmalogical agents and chemical probes requires a full characterization of the relevant peptides, including the structure of the carbohydrate part. In this review, the currently existing knowledge of O-glycosylation of conotoxins is described. Marine Drugs 2013-03-01 11 3 Review 10.3390/md11030623 623 642 1660-3397 2013-03-01 doi: 10.3390/md11030623 Gerrit Gerwig Henry Hocking Reto Stöcklin Johannis Kamerling Rolf Boelens http://www.mdpi.com/1660-3397/11/3/611 In the chemical investigation of marine unicellular bacteria, a new peptide, thalassospiramide G (1), along with thalassospiramides A and D (2–3), was discovered from a large culture of Thalassospira sp. The structure of thalassospiramide G, bearing γ-amino acids, such as 4-amino-5-hydroxy-penta-2-enoic acid (AHPEA), 4-amino-3,5-dihydroxy-pentanoic acid (ADPA), and unique 2-amino-1-(1H-indol-3-yl) ethanone (AIEN), was determined via extensive spectroscopic analysis. The absolute configuration of thalassospiramide D (3), including 4-amino-3-hydroxy-5-phenylpentanoic acid (AHPPA), was rigorously determined by 1H–1H coupling constant analysis and chemical derivatization. Thalassospiramides A and D (2–3) inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated mouse macrophage RAW 264.7 cells, with IC50 values of 16.4 and 4.8 μM, respectively. Marine Drugs 2013-02-26 11 3 Article 10.3390/md11030611 611 622 1660-3397 2013-02-26 doi: 10.3390/md11030611 Soohyun Um Yuna Pyee Eun-Hee Kim Sang Lee Jongheon Shin Dong-Chan Oh http://www.mdpi.com/1660-3397/11/3/599 Organic extracts of 20 species of French seaweed have been screened against Trypanosoma brucei rhodesiense trypomastigotes, the parasite responsible for sleeping sickness. These extracts have previously shown potent antiprotozoal activities in vitro against Plasmodium falciparum and Leishmania donovani. The selectivity of the extracts was also evaluated by testing cytotoxicity on a mammalian L6 cell line. The ethyl acetate extract of the brown seaweed, Bifurcaria bifurcata, showed strong trypanocidal activity with a mild selectivity index (IC50 = 0.53 µg/mL; selectivity index (SI) = 11.6). Bio-guided fractionation led to the isolation of eleganolone, the main diterpenoid isolated from this species. Eleganolone contributes only mildly to the trypanocidal activity of the ethyl acetate extract (IC50 = 45.0 µM, SI = 4.0). However, a selective activity against P. falciparum erythrocytic stages in vitro has been highlighted (IC50 = 7.9 µM, SI = 21.6). Marine Drugs 2013-02-26 11 3 Article 10.3390/md11030599 599 610 1660-3397 2013-02-26 doi: 10.3390/md11030599 Jean-Baptiste Gallé Barthélémy Attioua Marcel Kaiser Anne-Marie Rusig Annelise Lobstein Catherine Vonthron-Sénécheau http://www.mdpi.com/1660-3397/11/3/584 Palytoxin (PLTX) is the reference compound for a group of potent marine biotoxins, for which the molecular target is Na+/K+-ATPase. Indeed, ouabain (OUA), a potent blocker of the pump, is used to inhibit some PLTX effects in vitro. However, in an effort to explain incomplete inhibition of PLTX cytotoxicity, some studies suggest the possibility of two different binding sites on Na+/K+-ATPase. Hence, this study was performed to characterize PLTX binding to intact HaCaT keratinocytes and to investigate the ability of OUA to compete for this binding. PLTX binding to HaCaT cells was demonstrated by immunocytochemical analysis after 10 min exposure. An anti-PLTX monoclonal antibody-based ELISA showed that the binding was saturable and reversible, with a Kd of 3 × 10−10 M. However, kinetic experiments revealed that PLTX binding dissociation was incomplete, suggesting an additional, OUA-insensitive, PLTX binding site. Competitive experiments suggested that OUA acts as a negative allosteric modulator against high PLTX concentrations (0.3–1.0 × 10−7 M) and possibly as a non-competitive antagonist against low PLTX concentrations (0.1–3.0 × 10−9 M). Antagonism was supported by PLTX cytotoxicity inhibition at OUA concentrations that displaced PLTX binding (1 × 10−5 M). However, this inhibition was incomplete, supporting the existence of both OUA-sensitive and -insensitive PLTX binding sites. Marine Drugs 2013-02-26 11 3 Article 10.3390/md11030584 584 598 1660-3397 2013-02-26 doi: 10.3390/md11030584 Marco Pelin Sabrina Boscolo Mark Poli Silvio Sosa Aurelia Tubaro Chiara Florio http://www.mdpi.com/1660-3397/11/3/581 To recognize the most outstanding papers in the area of research, development and production of drugs from the sea, including marine natural product chemistry, that have been published in Marine Drugs, we would like to start an annual “Best Paper Award”. Marine Drugs 2013-02-26 11 3 Editorial 10.3390/md11030581 581 583 1660-3397 2013-02-26 doi: 10.3390/md11030581 Ophelia Han http://www.mdpi.com/1660-3397/11/2/571 A new cytotoxic 19-oxygenated steroid, nebrosteroid Q (1) and two new cytotoxic 19-norergosterols, nebrosteroids R and S (2 and 3) were isolated from the soft coral Nephthea chabrolii collected at San-Hsian-Tai. The structures of nebrosteroids Q–S (1–3) were elucidated by spectral analysis, and their cytotoxicity against selected cancer cells as well as antiviral activity against human cytomegalovirus (HCMV) were measured in vitro. Marine Drugs 2013-02-22 11 2 Article 10.3390/md11020571 571 580 1660-3397 2013-02-22 doi: 10.3390/md11020571 Shang-Kwei Wang Shyh-Yueh Puu Chang-Yih Duh http://www.mdpi.com/1660-3397/11/2/559 Genome sequences of the reef-building coral, Acropora digitifera, have been decoded. Acropora inhabits an environment with intense ultraviolet exposure and hosts the photosynthetic endosymbiont, Symbiodinium. Acropora homologs of all four genes necessary for biosynthesis of the photoprotective cyanobacterial compound, shinorine, are present. Among metazoans, these genes are found only in anthozoans. To gain further evolutionary insights into biosynthesis of photoprotective compounds and associated coral proteins, we surveyed the Acropora genome for 18 clustered genes involved in cyanobacterial synthesis of the anti-UV compound, scytonemin, even though it had not previously been detected in corals. We identified candidates for only 6 of the 18 genes, including tyrP, scyA, and scyB. Therefore, it does not appear that Acropora digitifera can synthesize scytonemin independently. On the other hand, molecular phylogenetic analysis showed that one tyrosinase gene is an ortholog of vertebrate tyrosinase genes and that the coral homologs, scyA and scyB, are similar to bacterial metabolic genes, phosphonopyruvate (ppyr) decarboxylase and glutamate dehydrogenase (GDH), respectively. Further genomic searches for ppyr gene-related biosynthetic components indicate that the coral possesses a metabolic pathway similar to the bacterial 2-aminoethylphosphonate (AEP) biosynthetic pathway. The results suggest that de novo synthesis of carbon-phosphorus compounds is performed in corals. Marine Drugs 2013-02-22 11 2 Short Note 10.3390/md11020559 559 570 1660-3397 2013-02-22 doi: 10.3390/md11020559 Eiichi Shoguchi Makiko Tanaka Takeshi Takeuchi Chuya Shinzato Nori Satoh http://www.mdpi.com/1660-3397/11/2/551 The marine fungus Chondrostereum sp. was collected from a soft coral of the species Sarcophyton tortuosum from the South China Sea. Three new compounds, chondrosterins F–H (1, 4 and 5), together with three known compounds, incarnal (2), arthrosporone (3), and (2E)-decene-4,6,8-triyn-1-ol (6), were isolated. Their structures were elucidated primarily based on NMR and MS data. Incarnal (2) exhibited potent cytotoxic activity against various cancer cell lines. Marine Drugs 2013-02-22 11 2 Article 10.3390/md11020551 551 558 1660-3397 2013-02-22 doi: 10.3390/md11020551 Hou-Jin Li Ting Chen Ying-Lu Xie Wen-Dan Chen Xiao-Feng Zhu Wen-Jian Lan http://www.mdpi.com/1660-3397/11/2/523 Jellyfish (cnidarians) have a worldwide distribution. Despite most being harmless, some species may cause local and also systemic reactions. Treatment of jellyfish envenomation is directed at: alleviating the local effects of venom, preventing further nematocyst discharges and controlling systemic reactions, including shock. In severe cases, the most important step is stabilizing and maintaining vital functions. With some differences between species, there seems to be evidence and consensus on oral/topical analgesics, hot water and ice packs as effective painkillers and on 30 s application of domestic vinegar (4%–6% acetic acid) to prevent further discharge of unfired nematocysts remaining on the skin. Conversely, alcohol, methylated spirits and fresh water should be carefully avoided, since they could massively discharge nematocysts; pressure immobilization bandaging should also be avoided, as laboratory studies show that it stimulates additional venom discharge from nematocysts. Most treatment approaches are presently founded on relatively weak evidence; therefore, further research (especially randomized clinical trials) is strongly recommended. Dissemination of appropriate treatment modalities should be deployed to better inform and educate those at risk. Adequate signage should be placed at beaches to notify tourists of the jellyfish risk. Swimmers in risky areas should wear protective equipment. Marine Drugs 2013-02-22 11 2 Review 10.3390/md11020523 523 550 1660-3397 2013-02-22 doi: 10.3390/md11020523 Luca Cegolon William Heymann John Lange Giuseppe Mastrangelo http://www.mdpi.com/1660-3397/11/2/504 We previously reported that a novel marine compound, xyloketal B, has strong antioxidative actions in different models of cardiovascular diseases. Induction of heme oxygenase-1 (HO-1), an important endogenous antioxidant enzyme, has been considered as a potential therapeutic strategy for cardiovascular diseases. We here investigated whether xyloketal B exhibits its antioxidant activity through induction of HO-1. In human umbilical vein endothelial cells (HUVECs), xyloketal B significantly induced HO-1 gene expression and translocation of the nuclear factor-erythroid 2-related factor 2 (Nrf-2) in a concentration- and time-dependent manner. The protection of xyloketal B against angiotensin II-induced apoptosis and reactive oxygen species (ROS) production could be abrogated by the HO-1 specific inhibitor, tin protoporphyrin-IX (SnPP). Consistently, the suppressive effects of xyloketal B on NADPH oxidase activity could be reversed by SnPP in zebrafish embryos. In addition, xyloketal B induced Akt and Erk1/2 phosphorylation in a concentration- and time-dependent manner. Furthermore, PI3K inhibitor LY294002 and Erk1/2 inhibitor U0126 suppressed the induction of HO-1 and translocation of Nrf-2 by xyloketal B, whereas P38 inhibitor SB203580 did not. In conclusion, xyloketal B can induce HO-1 expression via PI3K/Akt/Nrf-2 pathways, and the induction of HO-1 is mainly responsible for the antioxidant and antiapoptotic actions of xyloketal B. Marine Drugs 2013-02-18 11 2 Article 10.3390/md11020504 504 522 1660-3397 2013-02-18 doi: 10.3390/md11020504 Zhen-Xing Li Jian-Wen Chen Feng Yuan Yun-Ying Huang Li-Yan Zhao Jie Li Huan-Xing Su Jie Liu Ji-Yan Pang Yong-Cheng Lin Xi-Lin Lu Zhong Pei Guan-Lei Wang Yong-Yuan Guan http://www.mdpi.com/1660-3397/11/2/489 Several studies report temporal, geographical, and intra-individual variation in sponge metabolite yields. However, the internal and/or external factors that regulate the metabolite production remain poorly understood. Dysidea avara is a demosponge that produces sesquiterpenoids (avarol and derivatives) with interesting medical properties, which has prompted addressed studies to obtain enough amounts of these metabolites for research on drug discovery. Within this framework, specimens of Dysidea avara from a population of the Northwest Mediterranean were sampled and their secondary metabolites quantified to assess their variability and the possible relationship with external (seasonality, interactions with neighbors) and internal (reproductive stages) factors. The results show a variation of the amount of both avarol and its monoacetate derivative with time, with no clear relationship with seawater temperature. A trade-off with sponge reproduction was not found either. However, our results showed for the first time that sponges are able to increase production or accumulation of secondary metabolites in their peripheral zone depending on the nature of their neighbors. This finding could explain part of the high variability in the amount of secondary metabolites usually found in chemical ecology studies on sponges and opens new biotechnological approaches to enhance the metabolite yield in sponge cultures. Marine Drugs 2013-02-18 11 2 Article 10.3390/md11020489 489 503 1660-3397 2013-02-18 doi: 10.3390/md11020489 Sonia De Caralt Delphine Bry Nataly Bontemps Xavier Turon Maria-Jesus Uriz Bernard Banaigs http://www.mdpi.com/1660-3397/11/2/466 The indolocarbazole (ICZ) alkaloids have attracted much attention due to their unique structures and potential therapeutic applications. A series of ICZs were recently isolated and identified from a marine-derived actinomycete strain, Streptomyces sanyensis FMA. To elucidate the biosynthetic machinery associated with ICZs production in S. sanyensis FMA, PCR using degenerate primers was carried out to clone the FAD-dependent monooxygenase gene fragment for ICZ ring formation, which was used as a probe to isolate the 34.6-kb DNA region containing the spc gene cluster. Sequence analysis revealed genes for ICZ ring formation (spcO, D, P, C), sugar unit formation (spcA, B, E, K, J, I), glycosylation (spcN, G), methylation (spcMA, MB), as well as regulation (spcR). Their involvement in ICZ biosynthesis was confirmed by gene inactivation and heterologous expression in Streptomyces coelicolor M1152. This work represents the first cloning and characterization of an ICZ gene cluster isolated from a marine-derived actinomycete strain and would be helpful for thoroughly understanding the biosynthetic mechanism of ICZ glycosides. Marine Drugs 2013-02-06 11 2 Article 10.3390/md11020466 466 488 1660-3397 2013-02-06 doi: 10.3390/md11020466 Tong Li Yuanyuan Du Qiu Cui Jingtao Zhang Weiming Zhu Kui Hong Wenli Li http://www.mdpi.com/1660-3397/11/2/455 Six new casbane diterpenoids, named as sinularcasbanes A–F (1–6), along with six known analogues 7–12, were isolated from a South China Sea soft coral, Sinularia sp. The structures of the new compounds were elucidated by extensive spectroscopic analysis and by comparison with data reported in the literature. All compounds were evaluated for their cytotoxicity against selected cancer cell lines and the inhibition of lipopolysaccharide (LPS)-induced nitric oxide (NO) production in mouse peritoneal macrophages. Marine Drugs 2013-02-06 11 2 Article 10.3390/md11020455 455 465 1660-3397 2013-02-06 doi: 10.3390/md11020455 Jian Yin Min Zhao Minshan Ma Yuping Xu Zheng Xiang Yuepiao Cai Jianyong Dong Xinxiang Lei Kexin Huang Pengcheng Yan http://www.mdpi.com/1660-3397/11/2/440 The herein presented complete structure of the core oligosaccharide of lipopolysaccharide (LPS) P. shigelloides Polish Collection of Microorganisms (PCM) 2231 (serotype O17) was investigated by 1H, 13C NMR spectroscopy, mass spectrometry, chemical analyses and serological methods. The core oligosaccharide is composed of an undecasaccharide, which represents the second core type identified for P. shigelloides serotype O17 LPS. This structure is similar to that of the core oligosaccharide of P. shigelloides strains 302-73 (serotype O1) and 7-63 (serotype O17) and differs from these only by one sugar residue. Serological screening of 55 strains of P. shigelloides with the use of serum against identified core oligosaccharide conjugated with bovine serum albumin (BSA) indicated the presence of similar structures in the LPS core region of 28 O-serotypes. This observation suggests that the core oligosaccharide structure present in strain PCM 2231 could be the most common type among P. shigelloides lipopolysaccharides. Marine Drugs 2013-02-06 11 2 Article 10.3390/md11020440 440 454 1660-3397 2013-02-06 doi: 10.3390/md11020440 Anna Maciejewska Jolanta Lukasiewicz Marta Kaszowska Aleksandra Man-Kupisinska Wojciech Jachymek Czeslaw Lugowski http://www.mdpi.com/1660-3397/11/2/431 Marine microorganisms are of considerable interest as a promising source of enzymes with unsuspected potentials as catalysts for chemical synthesis. We describe here an efficient method for one-pot indolizine synthesis that has been developed using lipase A and lipase B from Candida antarctica as biocatalysts. As showed by HPLC/MS analysis, the yield in indolizines was higher in the presence of the biocatalyst than in absence of enzyme. Lipase A, from Candida antarctica, showed high catalytic activity and selectivity for the cycloaddition reactions. When the reactions were performed under ultrasound irradiation, the Candida antarctica lipase catalyzed reactions yielded pure indolozines, in good yields and in very short time. Marine Drugs 2013-02-06 11 2 Communication 10.3390/md11020431 431 439 1660-3397 2013-02-06 doi: 10.3390/md11020431 Rodica Dinica Bianca Furdui Ioana Ghinea Gabriela Bahrim Simon Bonte Martine Demeunynck http://www.mdpi.com/1660-3397/11/2/418 The cytotoxic effects and mechanism of action of clerosterol, isolated from the marine alga Codium fragile, were investigated in A2058 human melanoma cells. Clerosterol inhibited the growth of A2058 cells with an IC50 of 150 µM and induced apoptotic cell death, as evidenced by DNA fragmentation, an increase in the number of sub-G1 hypodiploid cells and the presence of apoptotic bodies. Clerosterol treatment caused the loss of mitochondrial membrane potential. Alterations in the expression of apoptosis-associated proteins in response to clerosterol treatment included upregulation of Bax, downregulation of Bcl-2 and activation of caspases 3 and 9. The pan-caspase inhibitor treatment attenuated the expression of the active form of caspases and cell death induced by clerosterol. The present results show that clerosterol exerts its cytotoxic effect in A2058 human melanoma cells by caspases-dependent apoptosis. Marine Drugs 2013-02-06 11 2 Article 10.3390/md11020418 418 430 1660-3397 2013-02-06 doi: 10.3390/md11020418 Areum Kim Youngki Lee Sang-Hyuck Kang Gi Kim Hye Kim Jin Hyun http://www.mdpi.com/1660-3397/11/2/399 In order to search for sulfated polysaccharides in different invertebrate connective tissues and to examine their biological activities, we have isolated three types of polysaccharides from the body wall of the three sea cucumbers Holothuria edulis, Apostichopus japonicas and Holothuria nobilis. The physicochemical properties and anticoagulant activities of these polysaccharides were examined and compared. The chemical composition analysis and nuclear magnetic resonance (NMR) analysis indicate that two types of polysaccharides, sulfated fucan and fucosylated chondroitin sulfate (FuCS), were found in all of the three species and in addition a neutral glycan was observed in H. edulis. The neutral α-glucan was firstly obtained from sea cucumber. The same type of polysaccharides from different species of sea cucumbers have similar physicochemical properties and anticoagulant activities, but those of different types of glycans are significantly different, possibly due to their different monosaccharide compositions, electric charges and average molecular weights. The FuCSs have stronger anticoagulant activities than the sulfated fucans, although the molecular sizes of the FuCSs are lower than those of the sulfated fucans, whereas the neutral glucan has no activity, as expected from the absence of sulfate. Thus, anticoagulant activities of the different type of polysaccharides are likely to relate to monosaccharide composition and sulfate content. Preliminary analysis suggests that the sulfation patterns of the FuCSs may result in the difference in anticoagulant activities. Our data could help elucidate the structure-activity relationship of the sea cucumber polysaccharides. Marine Drugs 2013-02-05 11 2 Article 10.3390/md11020399 399 417 1660-3397 2013-02-05 doi: 10.3390/md11020399 Lan Luo Mingyi Wu Li Xu Wu Lian Jingying Xiang Feng Lu Na Gao Chuang Xiao Shengmin Wang Jinhua Zhao http://www.mdpi.com/1660-3397/11/2/387 A new thiazolyl peptide, kocurin (1), was isolated from culture broths of a marine-derived Kocuria palustris. Its structural elucidation was accomplished using a combination of spectroscopic and chemical methods, including HRMS, extensive 1D and 2D NMR analysis, MS/MS fragmentation, and chemical degradation and Marfey’s analysis of the resulting amino acid residues. The structure herein reported corrects that previously assigned to PM181104 (3). Kocurin displayed activity against methicillin-resistant Staphylococcus aureus (MRSA), with MIC values in the submicromolar range. Marine Drugs 2013-02-04 11 2 Article 10.3390/md11020387 387 398 1660-3397 2013-02-04 doi: 10.3390/md11020387 Jesús Martín Thiciana da S. Sousa Gloria Crespo Sara Palomo Ignacio González José Tormo Mercedes de la Cruz Matthew Anderson Russell Hill Francisca Vicente Olga Genilloud Fernando Reyes http://www.mdpi.com/1660-3397/11/2/377 Lipid A, the hydrophobic anchor of lipopolysaccharide, is an essential component in the outer membrane of most Gram-negative bacteria. Food-borne pathogen Cronobacter sakazakii synthesizes two lipid A species, differing by the length of the secondary acyl chain. In this work, we identified three genes ESA02293, ESA02951 and ESA01386 encoding for the late acyltransferases of lipid A biosynthesis pathway in C. sakazakii. Based on the sequence alignment, proteins YP_001438378.1 encoded by ESA02293, YP_001439016.1 encoded by ESA02951, and YP_001437482.1 encoded by ESA01386 are homologous to E. coli LpxL, LpxP and LpxM, respectively. Functions of the three acyltransferases were confirmed by overexpressing the genes in E. coli, isolating lipid As and analyzing their structures using an ESI/MS. C. sakazakii LpxL and LpxM transfer a C14:0 secondary acyl chain to the 2′- and 3′-position of lipid A, respectively. C. sakazakii LpxP can transfer either a C16:1 or a C14:0 secondary acyl chains to the 2′-position of lipid A. Marine Drugs 2013-01-31 11 2 Article 10.3390/md11020377 377 386 1660-3397 2013-01-31 doi: 10.3390/md11020377 Liping Cai Yanyan Li Guanjun Tao Wen Guo Chan Zhang Xiaoyuan Wang http://www.mdpi.com/1660-3397/11/2/363 The lipid A moiety of Escherichia coli lipopolysaccharide is a hexaacylated disaccharide of glucosamine phosphorylated at the 1- and 4′-positions. It can be recognized by the TLR4/MD-2 complex of mammalian immune cells, leading to release of proinflammatory cytokines. The toxicity of lipid A depends on its structure. In this study, two E. coli mutants, HW001 and HW002, were constructed by deleting or integrating key genes related to lipid A biosynthesis in the chromosome of E. coli W3110. HW001 was constructed by deleting lacI and replacing lacZ with the Francisella novicida lpxE gene in the chromosome and only synthesizes monophosphoryl lipid A. HW002 was constructed by deleting lpxM in HW001 and synthesizes only the pentaacylated monophosphoryl lipid A. The structures of lipid A made in HW001 and HW002 were confirmed by thin layer chromatography and electrospray ionization mass spectrometry. HW001 and HW002 grew as well as the wild-type W3110. LPS purified from HW001 or HW002 was used to stimulate murine macrophage RAW264.7 cells, and less TNF-α were released. This study provides a feasible way to produce interesting lipid A species in E. coli. Marine Drugs 2013-01-31 11 2 Article 10.3390/md11020363 363 376 1660-3397 2013-01-31 doi: 10.3390/md11020363 Yaning Han Ye Li Jiuzhou Chen Yanzhen Tan Feng Guan Xiaoyuan Wang http://www.mdpi.com/1660-3397/11/2/350 3,4-Dibromo-5-(2-bromo-3,4-dihydroxy-6-(isopropoxymethyl)benzyl)benzene-1,2-diol (HPN) is a synthetic analogue of 3,4-dibromo-5-(2-bromo-3,4-dihydroxy-6-(ethoxymethyl)benzyl)benzene-1,2-diol (BPN), which is isolated from marine red alga Rhodomela confervoides with potent protein tyrosine phosphatase 1B (PTP1B) inhibition (IC50 = 0.84 μmol/L). The in vitro assay showed that HPN exhibited enhanced inhibitory activity against PTP1B with IC50 0.63 μmol/L and high selectivity against other PTPs (T cell protein tyrosine phosphatase (TCPTP), leucocyte antigen-related tyrosine phosphatase (LAR), Src homology 2-containing protein tyrosine phosphatase-1 (SHP-1) and SHP-2). The results of antihyperglycemic activity using db/db mouse model demonstrated that HPN significantly decreased plasma glucose (P < 0.01) after eight weeks treatment period. HPN lowered serum triglycerides and total cholesterol concentration in a dose-dependent manner. Besides, both of the high and medium dose groups of HPN remarkably decreased HbA1c levels (P < 0.05). HPN in the high dose group markedly lowered the insulin level compared to the model group (P < 0.05), whereas the effects were less potent than the positive drug rosiglitazone. Western blotting results showed that HPN decreased PTP1B levels in pancreatic tissue. Last but not least, the results of an intraperitoneal glucose tolerance test in Sprague–Dawley rats indicate that HPN have a similar antihyperglycemic activity as rosiglitazone. HPN therefore have potential for development as treatments for Type 2 diabetes. Marine Drugs 2013-01-30 11 2 Article 10.3390/md11020350 350 362 1660-3397 2013-01-30 doi: 10.3390/md11020350 Dayong Shi Shuju Guo Bo Jiang Chao Guo Tao Wang Luyong Zhang Jingya Li http://www.mdpi.com/1660-3397/11/2/332 Despite recent improvement in therapy, acute myeloid leukemia (AML) is still associated with high lethality. In the presented study, we analyzed the bioactive compound iodinin (1,6-dihydroxyphenazine 5,10-dioxide) from a marine actinomycetes bacterium for the ability to induce cell death in a range of cell types. Iodinin showed selective toxicity to AML and acute promyelocytic (APL) leukemia cells, with EC50 values for cell death up to 40 times lower for leukemia cells when compared with normal cells. Iodinin also successfully induced cell death in patient-derived leukemia cells or cell lines with features associated with poor prognostic such as FLT3 internal tandem duplications or mutated/deficient p53. The cell death had typical apoptotic morphology, and activation of apoptotic signaling proteins like caspase-3. Molecular modeling suggested that iodinin could intercalate between bases in the DNA in a way similar to the anti-cancer drug daunorubicin (DNR), causing DNA-strand breaks. Iodinin induced apoptosis in several therapy-resistant AML-patient blasts, but to a low degree in peripheral blood leukocytes, and in contrast to DNR, not in rat cardiomyoblasts. The low activity towards normal cell types that are usually affected by anti-leukemia therapy suggests that iodinin and related compounds represent promising structures in the development of anti-cancer therapy. Marine Drugs 2013-01-30 11 2 Article 10.3390/md11020332 332 349 1660-3397 2013-01-30 doi: 10.3390/md11020332 Lene Myhren Gyrid Nygaard Gro Gausdal Håvard Sletta Knut Teigen Kristin Degnes Kolbjørn Zahlsen Anders Brunsvik Øystein Bruserud Stein Døskeland Frode Selheim Lars Herfindal http://www.mdpi.com/1660-3397/11/2/316 Here we first demonstrate that asperolide A, a very recently reported marine-derived tetranorditerpenoid, leads to the inhibition of NCI-H460 lung carcinoma cell proliferation by G2/M arrest with the activation of the Ras/Raf/MEK/ERK signaling and p53-dependent p21 pathway. Treatment with 35 μM asperolide A (2 × IC50) resulted in a significant increase in the proportion of G2/M phase cells, about a 2.9-fold increase during 48 h. Immunoblot assays demonstrated time-dependent inhibition of G2/M regulatory proteins. Moreover, asperolide A significantly activated MAP kinases (ERK1/2, JNK and p38 MAP kinase) by phosphorylation, and only the inhibition of ERK activation by PD98059 reversed downregulation of G2/M regulatory proteins CDC2, and suppressed upregulation of p21 and p-p53 levels. Transfection of cells with dominant-negative Ras (RasN17) mutant genes up-regulated asperolide A-induced the decrease of cyclin B1 and CDC2, suppressed Raf, ERK activity and p53-p21 expression, and at last, abolished G2/M arrest. This study indicates that asperolide A-induced G2/M arrest in human NCI-H460 lung carcinoma cells relys on the participation of the Ras/Raf/MEK/ERK signaling pathway in p53-p21 stabilization. An in vivo study with asperolide A illustrated a marked inhibition of tumor growth, and little toxcity compared to Cisplatin therapy. Overall, these findings provide potential effectiveness and a theoretical basis for the therapeutic use of asperolide A in the treatment of malignancies. Marine Drugs 2013-01-29 11 2 Article 10.3390/md11020316 316 331 1660-3397 2013-01-29 doi: 10.3390/md11020316 Cuiting Lv Wenxia Sun Haofen Sun Shanjian Wei Ruohua Chen Bingui Wang Caiguo Huang http://www.mdpi.com/1660-3397/11/2/300 The dinoflagellate Dinophysis spp. is responsible for diarrhetic shellfish poisoning (DSP). In the bivalves exposed to the toxic bloom of the dinoflagellate, dinophysistoxin 3 (DTX3), the 7-OH acylated form of either okadaic acid (OA) or DTX1, is produced. We demonstrated in vitro acylation of OA with palmitoyl CoA in the presence of protein extract from the digestive gland, but not other tissues of the bivalve Mizuhopecten yessoensis. The yield of 7-O-palmitoyl OA reached its maximum within 2 h, was the highest at 37 °C followed by 28 °C, 16 °C and 4 °C and was the highest at pH 8 in comparison with the yields at pH 6 and pH 4. The transformation also proceeded when the protein extract was prepared from the bivalves Corbicula japonica and Crassostrea gigas. The OA binding protein OABP2 identified in the sponge Halichondria okadai was not detected in the bivalve M. yessoensis, the bivalve Mytilus galloprovincialis and the ascidian Halocynthia roretzi, though they are known to accumulate diarrhetic shellfish poisoning toxins. Since DTX3 does not bind to protein phosphatases 1 and 2A, the physiological target for OA and DTXs in mammalian cells, the acylation of DSP toxins would be related to a detoxification mechanism for the bivalve species. Marine Drugs 2013-01-29 11 2 Article 10.3390/md11020300 300 315 1660-3397 2013-01-29 doi: 10.3390/md11020300 Keiichi Konoki Tatsuya Onoda Ryuichi Watanabe Yuko Cho Shinnosuke Kaga Toshiyuki Suzuki Mari Yotsu-Yamashita http://www.mdpi.com/1660-3397/11/2/274 A series of N-14 sidechain substituted analogues of styelsamine (pyrido[4,3,2-mn]acridine) and cystodytin (pyrido[4,3,2-mn]acridin-4-one) alkaloids have been prepared and evaluated for their DNA binding affinity and antiproliferative activity towards a panel of human tumor cell lines. Overall it was found that styelsamine analogues were stronger DNA binders, with the natural products styelsamines B and D having particularly high affinity (Kapp 5.33 × 106 and 3.64 × 106 M−1, respectively). In comparison, the cystodytin iminoquinone alkaloids showed lower affinity for DNA, but were typically just as active as styelsamine analogues at inhibiting proliferation of tumor cells in vitro. Sub-panel selectivity towards non-small cell lung, melanoma and renal cancer cell lines were observed for a number of the analogues. Correlation was observed between whole cell activity and clogP, with the most potent antiproliferative activity being observed for 3-phenylpropanamide analogues 37 and 41 (NCI panel average GI50 0.4 μM and 0.32 μM, respectively) with clogP ~4.0–4.5. Marine Drugs 2013-01-28 11 2 Article 10.3390/md11020274 274 299 1660-3397 2013-01-28 doi: 10.3390/md11020274 Hugo Fong Brent Copp http://www.mdpi.com/1660-3397/11/1/266 Bullacta exarata was hydrolyzed with trypsin to prepare peptides; Hydrolysates were isolated by ultrafiltration and purified using G-25 gel filtration. The purity of the Bullacta exarata was demonstrated by HPLC and its peptide sequence analysis was detected. The effects of BEPT II and BEPT II-1 on the proliferation of PC-3 cells were examined using a MTT assay. BEPT II and BEPT II-1 significantly inhibited the proliferation of PC-3 cells in a time- and dose-dependent manner. Annexin V/PI double staining studies showed exposing PC-3 cells to 5, or 15 mg/mL BEPT II-1 for 24 h increased the percentage of the early stage of apoptotic cells from 11.22% to 22.09%. In addition, typical morphologic changes were observed in the cells with acridine orange/ethidium bromide staining. These data support that BEPT II-1 has anticancer properties and merits further investigation to understand the mechanisms of BEPT II-1-induced apoptosis in PC-3 cells. Marine Drugs 2013-01-23 11 1 Article 10.3390/md11010266 266 273 1660-3397 2013-01-23 doi: 10.3390/md11010266 Jianyin Ma Fangfang Huang Huanle Lin Xian Wang http://www.mdpi.com/1660-3397/11/1/253 The majority of the marine algal species, though completing their life cycle in seawater, are rarely susceptible to fouling, making them an important source of quorum sensing (QS) inhibitory substances. The separation and characterization of QS inhibitors are crucial for any potential application. Thirty marine macroalgae were tested for QS inhibition activity by using Chromobacterium violaceum CV026 as the reporter strain, and among them, Asparagopsis taxiformis showed antibacterial, as well as antiquorum, sensing activities. Cinnamaldehyde (75 mM) and methanol were used as positive and negative controls, respectively. The antiquorum sensing activity of A. taxiformis was further confirmed using the sensor strain, Serratia liquefaciens MG44, having green fluorescent protein (gfp). Methanolic extract of the alga was fractionated by solid phase extraction (SPE), and each fraction was tested for QS inhibition. Two types of activities were observed—zone of clearance (antibacterial activity) and zone of inhibition with or without finger-like projections (QS inhibition). Out of five SPE cartridges, Bond Elut PH showed clear separation of these two fractions. The Ion Cyclotron Resonance Fourier Transformation Mass Spectrometer (ICR-FT/MS) analysis of the fractions further supported the bioassay results. The presence of strong QS inhibitory compound in A. taxiformis indicates its potential use in antifouling preparations. Marine Drugs 2013-01-23 11 1 Article 10.3390/md11010253 253 265 1660-3397 2013-01-23 doi: 10.3390/md11010253 Bhavanath Jha Kumari Kavita Jenny Westphal Anton Hartmann Philippe Schmitt-Kopplin