http://www.mdpi.com/journal/marinedrugs/special_issues/marine-sponges/ Dear Colleagues, Since many years marine sponges have been ranked at the top with respect to the discovery of bioactive compounds with potential pharmaceutical applications. The diversity in chemical structures of sponge-derived metabolites is related to an equally diverse pattern of activities ranging from anti-fouling to anti-HIV properties. These discoveries have attracted the attention of bioprocess engineers, cell biologists, chemists, geneticist and microbiologists around the world to develop feasible strategies for obtaining sponge-derived metabolites at a larger scale. This is a ‘must’ to bridge the distance between the ocean and the hospital, or to start clinical trials in the first place. A few successful examples of introductions of marine sponge-derived pharmaceuticals have followed the discovery of the first bioactive compounds in sponges. Since these first publications in the 1950s the number of discovered bioactive compounds in sponges has exploded and in this special issue we aim to compile and review the state of the art of developments in sponge-chemistry, -biotechnology, -microbiology and –genetics to reap these fruits of the sea in a sustainable way. Prof. Dr. René Wijffels Dr. Detmer Sipkema Guest Editors {snippet name="submission_info"} http://www.mdpi.com/1660-3397/10/1/242/ Pregnane X receptor (PXR) has been reported to regulate the expression of drug-metabolizing enzymes, such as the cytochrome P450 3A (CYP3A) family and transporters, such as multiple drug resistance 1 (MDR1). Fucoxanthin, the major carotenoid in brown sea algae, is a putative chemopreventive agent. In this study, we determined whether fucoxanthin could overcome drug resistance through attenuation of rifampin-induced CYP3A4 and MDR1 gene expression by PXR-mediated pathways in HepG2 hepatoma cells. We found that fucoxanthin (1–10 μM) significantly attenuated rifampin (20 μM)-induced CYP3A4, MDR1 mRNA and CYP3A4 protein expression at 24 h of incubation. Mechanistically, fucoxanthin strongly attenuated the PXR-mediated CYP3A4 promoter activity in HepG2 cells. In addition, fucoxanthin attenuated constitutive androstane receptor (CAR)- and rPXR-mediated CYP3A4 promoter activity in this cell line. Using the mammalian two-hybrid assay, we found that fucoxanthin significantly decreased the interaction between PXR and SRC-1, a PXR co-activator. Thus, fucoxanthin can decrease rifampin-induced CYP3A4 and MDR1 expression through attenuation of PXR-mediated CYP3A4 promoter activation and interaction between PXR and co-activator. These findings could lead to potentially important new therapeutic and dietary approaches to reduce the frequency of adverse drug reactions. http://www.mdpi.com/1660-3397/10/1/242/ Mon, 23 Jan 2012 00:00:00 CET Marine Drugs 2012-01-23 10 1 Article 242 257 1660-3397 Fucoxanthin Attenuates Rifampin-Induced Cytochrome P450 3A4 (CYP3A4) and Multiple Drug Resistance 1 (MDR1) Gene Expression Through Pregnane X Receptor (PXR)-Mediated Pathways in Human Hepatoma HepG2 and Colon Adenocarcinoma LS174T Cells 2012-01-23 doi: 10.3390/md10010242 Cheng-Ling Liu Yun-Ping Lim Miao-Lin Hu http://www.mdpi.com/1660-3397/10/1/223/ The brominated pyrrole-imidazole Ageladine A was used for live imaging of the jellyfish (jellies) Nausithoe werneri, the sea anemone Metridium senile and the flatworm Macrostomum lignano. The fluorescence properties of Ageladine A allow for estimation of pH values in tissue and organs in living animals. The results showed that Nausithoe werneri had the most acidic areas in the tentacles and close to the mouth (pH 4–6.5), Metridium senile harbours aggregates of high acidity in the tentacles (pH 5) and in Macrostomum lignano, the rhabdoids, the gonads and areas close to the mouth were the most acidic with values down to pH 5. http://www.mdpi.com/1660-3397/10/1/223/ Thu, 19 Jan 2012 00:00:00 CET Marine Drugs 2012-01-19 10 1 Article 223 233 1660-3397 The Alkaloid Ageladine A, Originally Isolated from Marine Sponges, Used for pH-Sensitive Imaging of Transparent Marine Animals 2012-01-19 doi: 10.3390/md10010223 Ulf Bickmeyer http://www.mdpi.com/1660-3397/9/12/2643/ Lithistid sponges are known to produce a diverse array of compounds ranging from polyketides, cyclic and linear peptides, alkaloids, pigments, lipids, and sterols. A majority of these structurally complex compounds have very potent and interesting biological activities. It has been a decade since a thorough review has been published that summarizes the literature on the natural products reported from this amazing sponge order. This review provides an update on the current taxonomic classification of the Lithistida, describes structures and biological activities of 131 new natural products, and discusses highlights from the total syntheses of 16 compounds from marine sponges of the Order Lithistida providing a compilation of the literature since the last review published in 2002. http://www.mdpi.com/1660-3397/9/12/2643/ Thu, 15 Dec 2011 00:00:00 CET Marine Drugs 2011-12-15 9 12 Review 2643 2682 1660-3397 Natural Products from the Lithistida: A Review of the Literature since 2000 2011-12-15 doi: 10.3390/md9122643 Priscilla L. Winder Shirley A. Pomponi Amy E. Wright http://www.mdpi.com/1660-3397/9/12/2499/ Understanding the scale at which natural products vary the most is critical because it sheds light on the type of factors that regulate their production. The sponge Aplysina aerophoba is a common Mediterranean sponge inhabiting shallow waters in the Mediterranean and its area of influence in Atlantic Ocean. This species contains large concentrations of brominated alkaloids (BAs) that play a number of ecological roles in nature. Our research investigates the ecological variation in BAs of A. aerophoba from a scale of hundred of meters to thousand kilometers. We used a nested design to sample sponges from two geographically distinct regions (Canary Islands and Mediterranean, over 2500 km), with two zones within each region (less than 50 km), two locations within each zone (less than 5 km), and two sites within each location (less than 500 m). We used high-performance liquid chromatography to quantify multiple BAs and a spectrophotometer to quantify chlorophyll a (Chl a). Our results show a striking degree of variation in both natural products and Chl a content. Significant variation in Chl a content occurred at the largest and smallest geographic scales. The variation patterns of BAs also occurred at the largest and smallest scales, but varied depending on which BA was analyzed. Concentrations of Chl a and isofistularin-3 were negatively correlated, suggesting that symbionts may impact the concentration of some of these compounds. Our results underline the complex control of the production of secondary metabolites, with factors acting at both small and large geographic scales affecting the production of multiple secondary metabolites. http://www.mdpi.com/1660-3397/9/12/2499/ Mon, 28 Nov 2011 00:00:00 CET Marine Drugs 2011-11-28 9 12 Article 2499 2513 1660-3397 Relevant Spatial Scales of Chemical Variation in Aplysina aerophoba 2011-11-28 doi: 10.3390/md9122499 Oriol Sacristan-Soriano Bernard Banaigs Mikel A. Becerro http://www.mdpi.com/1660-3397/9/11/2469/ While investigating the cytotoxic activity of the methanol extract of an Australian marine sponge Stelletta sp. (Demospongiae), a new diketopiperazine, cyclo-(4-S-hydroxy-R-proline-R-isoleucine) (1), was isolated together with the known bengamides; A (2), F (3), N (4), Y (5), and bengazoles; Z (6), C4 (7) and C6 (8). The isolation and structure elucidation of the diketopiperazine (1), together with the activity of 1–8 against a panel of human and mammalian cell lines are discussed. http://www.mdpi.com/1660-3397/9/11/2469/ Tue, 22 Nov 2011 00:00:00 CET Marine Drugs 2011-11-22 9 11 Short Note 2469 2478 1660-3397 A New Diketopiperazine, Cyclo-(4-S-hydroxy-R-proline-R-isoleucine), from an Australian Specimen of the Sponge Stelletta sp. 2011-11-22 doi: 10.3390/md9112469 Simon P. B. Ovenden Jonathan L. Nielson Catherine H. Liptrot Richard H. Willis Dianne M. Tapiolas Anthony D. Wright Cherie A. Motti http://www.mdpi.com/1660-3397/9/11/2423/ Porifera have long been a reservoir for the discovery of bioactive compounds and drug discovery. Most research in the area has focused on sponges from tropical and temperate waters, but more recently the focus has shifted to the less accessible colder waters of the Antarctic and, to a lesser extent, the Arctic. The Antarctic region in particular has been a more popular location for natural products discovery and has provided promising candidates for drug development. This article reviews groups of bioactive compounds that have been isolated and reported from the southern reaches of the Arctic Circle, surveys the known sponge diversity present in the Arctic waters, and details a recent sponge collection by our group in the Aleutian Islands, Alaska. The collection has yielded previously undescribed sponge species along with primary activity against opportunistic infectious diseases, malaria, and HCV. The discovery of new sponge species and bioactive crude extracts gives optimism for the isolation of new bioactive compounds from a relatively unexplored source. http://www.mdpi.com/1660-3397/9/11/2423/ Mon, 21 Nov 2011 00:00:00 CET Marine Drugs 2011-11-21 9 11 Review 2423 2437 1660-3397 Advancement into the Arctic Region for Bioactive Sponge Secondary Metabolites 2011-11-21 doi: 10.3390/md9112423 Samuel Abbas Michelle Kelly John Bowling James Sims Amanda Waters Mark Hamann http://www.mdpi.com/1660-3397/9/11/2397/ Type IIα DNA topoisomerase (TopoIIα) is among the most important clinical drug targets for the treatment of cancer. Recently, the DNA repair protein Metnase was shown to enhance TopoIIα activity and increase resistance to TopoIIα poisons. Using in vitro DNA decatenation assays we show that neoamphimedine potently inhibits TopoIIα-dependent DNA decatenation in the presence of Metnase. Cell proliferation assays demonstrate that neoamphimedine can inhibit Metnase-enhanced cell growth with an IC50 of 0.5 µM. Additionally, we find that the apparent Km of TopoIIα for ATP increases linearly with higher concentrations of neoamphimedine, indicating ATP-competitive inhibition, which is substantiated by molecular modeling. These findings support the continued development of neoamphimedine as an anticancer agent, particularly in solid tumors that over-express Metnase. http://www.mdpi.com/1660-3397/9/11/2397/ Fri, 18 Nov 2011 00:00:00 CET Marine Drugs 2011-11-18 9 11 Article 2397 2408 1660-3397 Neoamphimedine Circumvents Metnase-Enhanced DNA Topoisomerase IIα Activity Through ATP-Competitive Inhibition 2011-11-18 doi: 10.3390/md9112397 Jessica Ponder Byong Hoon Yoo Adedoyin D. Abraham Qun Li Amanda K. Ashley Courtney L. Amerin Qiong Zhou Brian G. Reid Philip Reigan Robert Hromas Jac A. Nickoloff Daniel V. LaBarbera http://www.mdpi.com/1660-3397/9/11/2201/ Marine sponges are an extremely rich and important source of natural products. Mariculture is one solution to the so-called “supply problem” that often hampers further studies and development of novel compounds from sponges. We report the extended culture (767 days) at sea in depths of 10 and 20 m of three sponge species: Negombata magnifica, Amphimedon chloros and Theonella swinhoei that produce latrunculin-B, halitoxin and swinholide-A, respectively. Since sponge-associated microorganisms may be the true producers of many of the natural products found in sponges and also be linked to the health of the sponges, we examined the stability of the bacterial communities in cultured versus wild sponges. Growth rate of the sponges (ranging from 308 to 61 and −19 (%)(year−1) in N. magnifica, A. chloros and T. swinhoei, respectively) differed significantly between species but not between the two depths at which the species were cultivated. Survivorship varied from 96% to 57%. During culture all species maintained the content of the desired natural product. Denaturing gradient gel electrophoresis analysis of the sponge-associated bacterial consortia revealed that differences existed between cultured and wild sponges in T. swinhoei and A. chloros but the communities remained quite stable in N. magnifica. The cultivation technique for production of natural products was found to be most appropriate for N. magnifica, while for T. swinhoei and A. chloros it was less successful, because of poorer growth and survival rates and shifts in their bacterial consortia. http://www.mdpi.com/1660-3397/9/11/2201/ Mon, 07 Nov 2011 00:00:00 CET Marine Drugs 2011-11-07 9 11 Article 2201 2219 1660-3397 Examination of Marine-Based Cultivation of Three Demosponges for Acquiring Bioactive Marine Natural Products 2011-11-07 doi: 10.3390/md9112201 Oded Bergman Boaz Mayzel Matthew A. Anderson Muki Shpigel Russell T. Hill Micha Ilan http://www.mdpi.com/1660-3397/9/11/2176/ Pectenotoxin-2 (PTX-2), which was first identified as a cytotoxic entity in marine sponges, has been reported to display significant cytotoxicity to human cancer cells where it inhibits mitotic separation and cytokinesis through the depolymerization of actin filaments. In the late stage of endoreduplication, the effects of PTX-2 on different cancer cells involves: (i) down-regulation of anti-apoptotic Bcl-2 members and IAP family proteins; (ii) up-regulation of pro-apoptotic Bax protein and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-receptor 1/receptor 2 (DR4/DR5); and (iii) mitochondrial dysfunction. In addition, PTX-2 induces apoptotic effects through suppression of the nuclear factor κB (NF-κB) signaling pathway in several cancer cells. Analysis of cell cycle regulatory proteins showed that PTX-2 increases phosphorylation of Cdc25c and decreases protein levels of Cdc2 and cyclin B1. Cyclin-dependent kinase (Cdk) inhibitor p21 and Cdk2, which are associated with the induction of endoreduplication, were upregulated. Furthermore, it was found that PTX-2 suppressed telomerase activity through the transcriptional and post-translational suppression of hTERT. The purpose of this review was to provide an update regarding the anti-cancer mechanism of PTX-2, with a special focus on its effects on different cellular signaling cascades. http://www.mdpi.com/1660-3397/9/11/2176/ Wed, 02 Nov 2011 00:00:00 CET Marine Drugs 2011-11-02 9 11 Review 2176 2187 1660-3397 Pectenotoxin-2 from Marine Sponges: A Potential Anti-Cancer Agent—A Review 2011-11-02 doi: 10.3390/md9112176 Gi-Young Kim Wun-Jae Kim Yung Hyun Choi http://www.mdpi.com/1660-3397/9/10/2131/ Protein kinases play a critical role in cell regulation and their deregulation is a contributing factor in an increasing list of diseases including cancer. Marine sponges have yielded over 70 novel compounds to date that exhibit significant inhibitory activity towards a range of protein kinases. These compounds, which belong to diverse structural classes, are reviewed herein, and ordered based upon the kinase that they inhibit. Relevant synthetic studies on the marine natural product kinase inhibitors have also been included. http://www.mdpi.com/1660-3397/9/10/2131/ Mon, 24 Oct 2011 00:00:00 CEST Marine Drugs 2011-10-24 9 10 Review 2131 2154 1660-3397 Kinase Inhibitors from Marine Sponges 2011-10-24 doi: 10.3390/md9102131 Danielle Skropeta Natalie Pastro Ana Zivanovic http://www.mdpi.com/1660-3397/9/10/2010/ Bacterial biofilms are surface-attached communities of microorganisms that are protected by an extracellular matrix of biomolecules. In the biofilm state, bacteria are significantly more resistant to external assault, including attack by antibiotics. In their native environment, bacterial biofilms underpin costly biofouling that wreaks havoc on shipping, utilities, and offshore industry. Within a host environment, they are insensitive to antiseptics and basic host immune responses. It is estimated that up to 80% of all microbial infections are biofilm-based. Biofilm infections of indwelling medical devices are of particular concern, since once the device is colonized, infection is almost impossible to eliminate. Given the prominence of biofilms in infectious diseases, there is a notable effort towards developing small, synthetically available molecules that will modulate bacterial biofilm development and maintenance. Here, we highlight the development of small molecules that inhibit and/or disperse bacterial biofilms specifically through non-microbicidal mechanisms. Importantly, we discuss several sets of compounds derived from marine sponges that we are developing in our labs to address the persistent biofilm problem. We will discuss: discovery/synthesis of natural products and their analogues—including our marine sponge-derived compounds and initial adjuvant activity and toxicological screening of our novel anti-biofilm compounds. http://www.mdpi.com/1660-3397/9/10/2010/ Wed, 19 Oct 2011 00:00:00 CEST Marine Drugs 2011-10-19 9 10 Review 2010 2035 1660-3397 Anti-Biofilm Compounds Derived from Marine Sponges 2011-10-19 doi: 10.3390/md9102010 Sean D. Stowe Justin J. Richards Ashley T. Tucker Richele Thompson Christian Melander John Cavanagh http://www.mdpi.com/1660-3397/9/7/1210/ Chemical investigation of the Mediterranean sponge Sarcotragus spinosulus led to the isolation of a new hydroxylated nonaprenylhydroquinone, along with two known metabolites, hepta- and octaprenylhydroquinones. The structure of the new metabolite was assigned by extensive 1D and 2D NMR analyses and MS studies. The antileukemic effect of the three compounds towards the chronic myelogenous leukemia (CML) cells line K562 was also evaluated. http://www.mdpi.com/1660-3397/9/7/1210/ Thu, 07 Jul 2011 00:00:00 CEST Marine Drugs 2011-07-07 9 7 Article 1210 1219 1660-3397 A New Hydroxylated Nonaprenylhydroquinone from the Mediterranean Marine Sponge Sarcotragus spinosulus 2011-07-07 doi: 10.3390/md9071210 Charline Abed Nathalie Legrave Maeva Dufies Guillaume Robert Vincent Guérineau Jean Vacelet Patrick Auberger Philippe Amade Mohamed Mehiri http://www.mdpi.com/1660-3397/8/6/1731/ Marine sponges produce secondary metabolites that can be used as a natural source for the design of new drugs and cosmetics. There is, however, a supply problem with these natural substances for research and eventual commercialisation of the products. In situ sponge aquaculture is nowadays one of the most reliable methods to supply pharmaceutical companies with sufficient quantities of the target compound. In this study, we focus on the aquaculture of the sponge Dysidea avara (Schmidt, 1862), which produces avarol, a sterol with interesting pharmaceutical attributes. The soft consistency of this species makes the traditional culture method based on holding explants on ropes unsuitable. We have tested alternative culture methods for D. avara and optimized the underwater structures to hold the sponges to be used in aquaculture. Explants of this sponge were mounted on horizontal ropes, inside small cages or glued to substrates. Culture efficiency was evaluated by determination of sponge survival, growth rates, and bioactivity (as an indication of production of the target metabolite). While the cage method was the best method for explant survival, the glue method was the best one for explant growth and the rope method for bioactivity. http://www.mdpi.com/1660-3397/8/6/1731/ Wed, 26 May 2010 00:00:00 CEST Marine Drugs 2010-05-26 8 6 Article 1731 1742 1660-3397 In Situ Aquaculture Methods for Dysidea avara (Demospongiae, Porifera) in the Northwestern Mediterranean 2010-05-26 doi: 10.3390/md8061731 De Caralt Sánchez-Fontenla Uriz Wijffels http://www.mdpi.com/1660-3397/8/5/1550/ We report on screening tests of 66 extracts obtained from 35 marine sponge species from the Caribbean Sea (Curaçao) and from eight species from the Great Barrier Reef (Lizard Island). Extracts were prepared in aqueous and organic solvents and were tested for hemolytic, hemagglutinating, antibacterial and anti-acetylcholinesterase (AChE) activities, as well as their ability to inhibit or activate cell protein phosphatase 1 (PP1). The most interesting activities were obtained from extracts of Ircinia felix, Pandaros acanthifolium, Topsentia ophiraphidites, Verongula rigida and Neofibularia nolitangere. Aqueous and organic extracts of I. felix and V. rigida showed strong antibacterial activity. Topsentia aqueous and some organic extracts were strongly hemolytic, as were all organic extracts from I. felix. The strongest hemolytic activity was observed in aqueous extracts from P. acanthifolium. Organic extracts of N. nolitangere and I. felix inhibited PP1. The aqueous extract from Myrmekioderma styx possessed the strongest hemagglutinating activity, whilst AChE inhibiting activity was found only in a few sponges and was generally weak, except in the methanolic extract of T. ophiraphidites. http://www.mdpi.com/1660-3397/8/5/1550/ Wed, 28 Apr 2010 00:00:00 CEST Marine Drugs 2010-04-28 8 5 Article 1550 1566 1660-3397 Biological Activities of Aqueous and Organic Extracts from Tropical Marine Sponges 2010-04-28 doi: 10.3390/md8051550 Sepčić Kauferstein Mebs Turk http://www.mdpi.com/1660-3397/8/4/1417/ The subject of this review is the biodiversity of marine sponges and associated microbes which have been reported to produce therapeutically important compounds, along with the contextual information on their geographic distribution. Class Demospongiae and the orders Halichondrida, Poecilosclerida and Dictyoceratida are the richest sources of these compounds. Among the microbial associates, members of the bacterial phylum Actinobacteria and fungal division Ascomycota have been identified to be the dominant producers of therapeutics. Though the number of bacterial associates outnumber the fungal associates, the documented potential of fungi to produce clinically active compounds is currently more important than that of bacteria. Interestingly, production of a few identical compounds by entirely different host-microbial associations has been detected in both terrestrial and marine environments. In the Demospongiae, microbial association is highly specific and so to the production of compounds. Besides, persistent production of bioactive compounds has also been encountered in highly specific host-symbiont associations. Though spatial and temporal variations are known to have a marked effect on the quality and quantity of bioactive compounds, only a few studies have covered these dimensions. The need to augment production of these compounds through tissue culture and mariculture has also been stressed. The reviewed database of these compounds is available at www.niobioinformatics.in/drug.php. http://www.mdpi.com/1660-3397/8/4/1417/ Thu, 22 Apr 2010 00:00:00 CEST Marine Drugs 2010-04-22 8 4 Review 1417 1468 1660-3397 Marine Drugs from Sponge-Microbe Association—A Review 2010-04-22 doi: 10.3390/md8041417 Thomas Kavlekar LokaBharathi http://www.mdpi.com/1660-3397/8/4/1394/ Manynatural products with biologically interesting structures have been isolated from marine animals and plants such as sponges, corals, worms, etc. Some of them are discorhabdin alkaloids. The discorhabdin alkaloids (discorhabdin A-X), isolated from marine sponges, have a unique structure with azacarbocyclic spirocyclohexanone and pyrroloiminoquinone units. Due to their prominent potent antitumor activity, discorhabdins have attracted considerable attention. Many studies have been reported toward the synthesis of discorhabdins. We have accomplished the first total synthesis of discorhabdin A (1), having the strongest activity in vitro among discorhabdins in 2003. In 2009, we have also accomplished the first total synthesis of prianosin B (2), having the 16,17-dehydropyrroloiminoquinone moiety, by a novel dehydrogenation reaction with a catalytic amount of NaN3. These synthetic studies, as well as syntheses of the discorhabdins by various chemists to-date, are reviewed here. http://www.mdpi.com/1660-3397/8/4/1394/ Wed, 21 Apr 2010 00:00:00 CEST Marine Drugs 2010-04-21 8 4 Review 1394 1416 1660-3397 Synthesis of the Marine Pyrroloiminoquinone Alkaloids, Discorhabdins 2010-04-21 doi: 10.3390/md8041394 Wada Fujioka Kita http://www.mdpi.com/1660-3397/8/4/1059/ Marine sponges are an excellent source of bioactive secondary metabolites with potential therapeutic value in the treatment of diseases. One group of compounds of particular interest is the microtubule-stabilizing agents, the most well-known compound of this group being paclitaxel (Taxol®), an anti-cancer compound isolated from the bark and leaves of the Pacific yew tree. This review focuses on two of the more recent additions to this important class of drugs, peloruside A and zampanolide, both isolated from marine sponges. Peloruside A was isolated from Mycale hentscheli collected in New Zealand coastal waters, and it already shows promising anti-cancer activity. Two other potent bioactive compounds with different modes of action but isolated from the same sponge, mycalamide A and pateamine, will also be discussed. The fourth compound, zampanolide, most recently isolated from the Tongan sponge Cacospongia mycofijiensis, has only recently been added to the microtubule-stabilizing group of compounds, and further work is in progress to determine its activity profile relative to peloruside A and other drugs of this class. http://www.mdpi.com/1660-3397/8/4/1059/ Wed, 31 Mar 2010 00:00:00 CEST Marine Drugs 2010-03-31 8 4 Review 1059 1079 1660-3397 Microtubule-Stabilizing Drugs from Marine Sponges: Focus on Peloruside A and Zampanolide 2010-03-31 doi: 10.3390/md8041059 Miller Singh Northcote http://www.mdpi.com/1660-3397/8/3/810/ A number of natural products from marine sponges, such as cyclodepsipeptides, have been identified. The structural characteristics of this family of cyclic peptides include various unusual amino acid residues and unique N-terminal polyketide-derived moieties. Papuamides are representatives of a class of marine sponge derived cyclic depsipeptides, including callipeltin A, celebesides A and B, homophymine A, mirabamides, microspinosamide, neamphamide A and theopapuamides. They are thought to have cytoprotective activity against HIV-1 in vitro by inhibiting viral entry. Jasplakinolide, a representative member of marine sponge-derived cyclodepsipeptides that include arenastatin A, geodiamolides, homophymines, spongidepsin and theopapuamides, is a potent inducer of actin polymerization in vitro. Although actin dynamics is essential for tumor metasasis, no actin targeting drugs have been used in clinical trials due to their severe cytotoxicity. Nonetheless, the actin cytoskeleton remains a potential target for anti-cancer drug development. These features imply the use of cyclodepsipeptides as molecular models in drug research. http://www.mdpi.com/1660-3397/8/3/810/ Mon, 22 Mar 2010 00:00:00 CET Marine Drugs 2010-03-22 8 3 Review 810 834 1660-3397 Cyclodepsipeptides from Marine Sponges: Natural Agents for Drug Research 2010-03-22 doi: 10.3390/md8030810 Andavan Lemmens-Gruber http://www.mdpi.com/1660-3397/7/4/787/ Sponges can provide potential drugs against many major world-wide occurring diseases. Despite the high potential of sponge derived drugs no sustainable production method has been developed. Thus far it is not fully understood why, when, where and how these metabolites are produced in sponges. For the near future sea-based sponge culture seems to be the best production method. However, for controlled production in a defined system it is better to develop in vitro production methods, like in vitro sponge culture or even better sponge cell culture, culture methods for symbionts or the transfer of production routes into another host. We still have insufficient information about the background of metabolite production in sponges. Before production methods are developed we should first focus on factors that can induce metabolite production. This could be done in the natural habitat by studying the relation between stress factors (such as predation) and the production of bioactive metabolites. The location of production within the sponge should be identified in order to choose between sponge cell culture and symbiont culture. Alternatively the biosynthetic pathways could be introduced into hosts that can be cultured. For this the biosynthetic pathway of metabolite production should be unraveled, as well as the genes involved. This review discusses the current state of sponge metabolite production and the steps that need to be taken to develop commercial production techniques. The different possible production techniques are also discussed. http://www.mdpi.com/1660-3397/7/4/787/ Wed, 02 Dec 2009 00:00:00 CET Marine Drugs 2009-12-02 7 4 Article 787 802 1660-3397 Towards Commercial Production of Sponge Medicines 2009-12-02 doi: 10.3390/md7040787 Marieke Koopmans Dirk Martens Rene H. Wijffels http://www.mdpi.com/1660-3397/7/4/523/ A new polyunsaturated brominated fatty acid possessing acetylenic bonds 1 was isolated from the Indonesian sponge Haliclona sp. The structure of compound 1 was elucidated by analyzing its spectral data. It showed moderate cytotoxicity against cultured cells. http://www.mdpi.com/1660-3397/7/4/523/ Mon, 02 Nov 2009 00:00:00 CET Marine Drugs 2009-11-02 7 4 Article 523 527 1660-3397 A New Polyunsaturated Brominated Fatty Acid from a Haliclona Sponge 2009-11-02 doi: 10.3390/md7040523 Satoe Aratake Agus Trianto Novriyandi Hanif Nicole J. De Voogd Junichi Tanaka http://www.mdpi.com/1660-3397/7/3/445/ A new cyclic diamine, 1,5-diazacyclohenicosane (1), was isolated from samples of the marine sponge Mycale sp. collected at Lamu Island (Kenya). Its structure was determined by a combination of spectroscopic techniques, including (+)-HRESIMS and 1D and 2D NMR spectroscopy. The compound displayed cytotoxicity at the μM level against three human tumor cell lines. http://www.mdpi.com/1660-3397/7/3/445/ Tue, 15 Sep 2009 00:00:00 CEST Marine Drugs 2009-09-15 7 3 Article 445 450 1660-3397 1,5-Diazacyclohenicosane, a New Cytotoxic Metabolite from the Marine Sponge Mycale sp. 2009-09-15 doi: 10.3390/md7030445 Laura Coello María Jesús Martín Fernando Reyes http://www.mdpi.com/1660-3397/7/3/435/ Two new jaspamide derivatives 2 and 3, together with the parent compound jaspamide (1) have been isolated from the marine sponge Jaspis splendens collected in Kalimantan (Indonesia). The structures of the new compounds were unambiguously elucidated based on 1D and 2D NMR spectral data, mass spectrometry and comparison with jaspamide (1). The new derivatives inhibited the growth of mouse lymphoma (L5178Y) cell line in vitro with IC50 values of http://www.mdpi.com/1660-3397/7/3/435/ Tue, 15 Sep 2009 00:00:00 CEST Marine Drugs 2009-09-15 7 3 Article 435 444 1660-3397 Two New Jaspamide Derivatives from the Marine Sponge Jaspis splendens 2009-09-15 doi: 10.3390/md7030435 Sherif S. Ebada Victor Wray Nicole J. De Voogd Zhiwei Deng Wenhan Lin Peter Proksch