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Mar. Drugs, Volume 13, Issue 6 (June 2015), Pages 3259-3991

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Open AccessReview Can Some Marine-Derived Fungal Metabolites Become Actual Anticancer Agents?
Mar. Drugs 2015, 13(6), 3950-3991; https://doi.org/10.3390/md13063950
Received: 15 April 2015 / Revised: 4 June 2015 / Accepted: 9 June 2015 / Published: 19 June 2015
Cited by 33 | PDF Full-text (457 KB) | HTML Full-text | XML Full-text
Abstract
Marine fungi are known to produce structurally unique secondary metabolites, and more than 1000 marine fungal-derived metabolites have already been reported. Despite the absence of marine fungal-derived metabolites in the current clinical pipeline, dozens of them have been classified as potential chemotherapy candidates
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Marine fungi are known to produce structurally unique secondary metabolites, and more than 1000 marine fungal-derived metabolites have already been reported. Despite the absence of marine fungal-derived metabolites in the current clinical pipeline, dozens of them have been classified as potential chemotherapy candidates because of their anticancer activity. Over the last decade, several comprehensive reviews have covered the potential anticancer activity of marine fungal-derived metabolites. However, these reviews consider the term “cytotoxicity” to be synonymous with “anticancer agent”, which is not actually true. Indeed, a cytotoxic compound is by definition a poisonous compound. To become a potential anticancer agent, a cytotoxic compound must at least display (i) selectivity between normal and cancer cells (ii) activity against multidrug-resistant (MDR) cancer cells; and (iii) a preferentially non-apoptotic cell death mechanism, as it is now well known that a high proportion of cancer cells that resist chemotherapy are in fact apoptosis-resistant cancer cells against which pro-apoptotic drugs have more than limited efficacy. The present review thus focuses on the cytotoxic marine fungal-derived metabolites whose ability to kill cancer cells has been reported in the literature. Particular attention is paid to the compounds that kill cancer cells through non-apoptotic cell death mechanisms. Full article
(This article belongs to the Special Issue Bioactive Compounds from Marine Fungi)
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Open AccessArticle Induction of Apoptosis and Antitumor Activity of Eel Skin Mucus, Containing Lactose-Binding Molecules, on Human Leukemic K562 Cells
Mar. Drugs 2015, 13(6), 3936-3949; https://doi.org/10.3390/md13063936
Received: 5 March 2015 / Revised: 2 June 2015 / Accepted: 5 June 2015 / Published: 19 June 2015
Cited by 8 | PDF Full-text (1627 KB) | HTML Full-text | XML Full-text
Abstract
For innate immune defense, lower animals such as fish and amphibian are covered with skin mucus, which acts as both a mechanical and biochemical barrier. Although several mucus sources have been isolated and studied for their biochemical and immunological functions, the precise mechanism(s)
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For innate immune defense, lower animals such as fish and amphibian are covered with skin mucus, which acts as both a mechanical and biochemical barrier. Although several mucus sources have been isolated and studied for their biochemical and immunological functions, the precise mechanism(s) of action remains unknown. In the present study, we additionally found the eel skin mucus (ESM) to be a promising candidate for use in anti-tumor therapy. Our results showed that the viability of K562 cells was decreased in a dose-dependent manner by treatment with the isolated ESM. The cleaved forms of caspase-9, caspase-3 and poly adenosine diphosphate-ribose polymerase were increased by ESM. The levels of Bax expression and released cytochrome C were also increased after treatment with ESM. Furthermore, during the ESM mediated-apoptosis, phosphorylation levels of ERK1/2 and p38 but not JNK were increased and cell viabilities of the co-treated cells with ESM and inhibitors of ERK 1/2 or p38 were also increased. In addition, treatment with lactose rescued the ESM-mediated decrease in cell viability, indicating lactose-containing glycans in the leukemia cells acted as a counterpart of the ESM for interaction. Taken together, these results suggest that ESM could induce mitochondria-mediated apoptosis through membrane interaction of the K562 human leukemia cells. To the best of our knowledge, this is the first observation that ESM has anti-tumor activity in human cells. Full article
(This article belongs to the Special Issue Marine Glycoconjugates)
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Open AccessArticle Persistent Contamination of Octopuses and Mussels with Lipophilic Shellfish Toxins during Spring Dinophysis Blooms in a Subtropical Estuary
Mar. Drugs 2015, 13(6), 3920-3935; https://doi.org/10.3390/md13063920
Received: 16 April 2015 / Revised: 8 May 2015 / Accepted: 28 May 2015 / Published: 18 June 2015
Cited by 3 | PDF Full-text (589 KB) | HTML Full-text | XML Full-text
Abstract
This study investigates the occurrence of diarrhetic shellfish toxins (DSTs) and their producing phytoplankton species in southern Brazil, as well as the potential for toxin accumulation in co-occurring mussels (Perna perna) and octopuses (Octopus vulgaris). During the spring in
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This study investigates the occurrence of diarrhetic shellfish toxins (DSTs) and their producing phytoplankton species in southern Brazil, as well as the potential for toxin accumulation in co-occurring mussels (Perna perna) and octopuses (Octopus vulgaris). During the spring in 2012 and 2013, cells of Dinophysis acuminata complex were always present, sometimes at relatively high abundances (max. 1143 cells L−1), likely the main source of okadaic acid (OA) in the plankton (max. 34 ng L−1). Dinophysis caudata occurred at lower cell densities in 2013 when the lipophilic toxins pectenotoxin-2 (PTX-2) and PTX-2 seco acid were detected in plankton and mussel samples. Here, we report for the first time the accumulation of DSTs in octopuses, probably linked to the consumption of contaminated bivalves. Perna perna mussels were consistently contaminated with different DSTs (max. 42 µg kg−1), and all octopuses analyzed (n = 5) accumulated OA in different organs/tissues: digestive glands (DGs) > arms > gills > kidneys > stomach + intestine. Additionally, similar concentrations of 7-O-palmytoyl OA and 7-O-palmytoly dinophysistoxin-1 (DTX-1) were frequently detected in the hepatopancreas of P. perna and DGs of O. vulgaris. Therefore, octopuses can be considered a potential vector of DSTs to both humans and top predators such as marine mammals. Full article
(This article belongs to the Special Issue Okadaic Acid and Dinophysis Toxins)
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Open AccessArticle Structural Characterization of New Peptide Variants Produced by Cyanobacteria from the Brazilian Atlantic Coastal Forest Using Liquid Chromatography Coupled to Quadrupole Time-of-Flight Tandem Mass Spectrometry
Mar. Drugs 2015, 13(6), 3892-3919; https://doi.org/10.3390/md13063892
Received: 26 February 2015 / Revised: 14 May 2015 / Accepted: 21 May 2015 / Published: 18 June 2015
Cited by 5 | PDF Full-text (751 KB) | HTML Full-text | XML Full-text
Abstract
Cyanobacteria from underexplored and extreme habitats are attracting increasing attention in the search for new bioactive substances. However, cyanobacterial communities from tropical and subtropical regions are still largely unknown, especially with respect to metabolite production. Among the structurally diverse secondary metabolites produced by
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Cyanobacteria from underexplored and extreme habitats are attracting increasing attention in the search for new bioactive substances. However, cyanobacterial communities from tropical and subtropical regions are still largely unknown, especially with respect to metabolite production. Among the structurally diverse secondary metabolites produced by these organisms, peptides are by far the most frequently described structures. In this work, liquid chromatography/electrospray ionization coupled to high resolution quadrupole time-of-flight tandem mass spectrometry with positive ion detection was applied to study the peptide profile of a group of cyanobacteria isolated from the Southeastern Brazilian coastal forest. A total of 38 peptides belonging to three different families (anabaenopeptins, aeruginosins, and cyanopeptolins) were detected in the extracts. Of the 38 peptides, 37 were detected here for the first time. New structural features were proposed based on mass accuracy data and isotopic patterns derived from full scan and MS/MS spectra. Interestingly, of the 40 surveyed strains only nine were confirmed to be peptide producers; all of these strains belonged to the order Nostocales (three Nostoc sp., two Desmonostoc sp. and four Brasilonema sp.). Full article
(This article belongs to the Special Issue Compounds from Cyanobacteria)
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Open AccessArticle Ecklonia cava Polyphenol Has a Protective Effect against Ethanol-Induced Liver Injury in a Cyclic AMP-Dependent Manner
Mar. Drugs 2015, 13(6), 3877-3891; https://doi.org/10.3390/md13063877
Received: 12 March 2015 / Revised: 23 May 2015 / Accepted: 9 June 2015 / Published: 18 June 2015
Cited by 13 | PDF Full-text (531 KB) | HTML Full-text | XML Full-text
Abstract
Previously, we showed that Ecklonia cava polyphenol (ECP) treatment suppressed ethanol-induced increases in hepatocyte death by scavenging intracellular reactive oxygen species (ROS) and maintaining intracellular glutathione levels. Here, we examined the effects of ECP on the activities of alcohol-metabolizing enzymes and their regulating
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Previously, we showed that Ecklonia cava polyphenol (ECP) treatment suppressed ethanol-induced increases in hepatocyte death by scavenging intracellular reactive oxygen species (ROS) and maintaining intracellular glutathione levels. Here, we examined the effects of ECP on the activities of alcohol-metabolizing enzymes and their regulating mechanisms in ethanol-treated hepatocytes. Isolated hepatocytes were incubated with or without 100 mM ethanol. ECP was dissolved in dimethylsulfoxide. ECP was added to cultured cells that had been incubated with or without ethanol. The cells were incubated for 0–24 h. In cultured hepatocytes, the ECP treatment with ethanol inhibited cytochrome P450 2E1 (CYP2E1) expression and activity, which is related to the production of ROS when large quantities of ethanol are oxidized. On the other hand, ECP treatment with ethanol increased the activity of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase. These changes in activities of CYP2E1 and ADH were suppressed by treatment with H89, an inhibitor of protein kinase A. ECP treatment with ethanol enhanced cyclic AMP concentrations compared with those of control cells. ECP may be a candidate for preventing ethanol-induced liver injury via regulating alcohol metabolic enzymes in a cyclic AMP-dependent manner. Full article
(This article belongs to the Special Issue Marine Functional Food)
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Open AccessArticle Characterization of Shrimp Oil from Pandalus borealis by High Performance Liquid Chromatography and High Resolution Mass Spectrometry
Mar. Drugs 2015, 13(6), 3849-3876; https://doi.org/10.3390/md13063849
Received: 30 April 2015 / Revised: 2 June 2015 / Accepted: 2 June 2015 / Published: 18 June 2015
Cited by 8 | PDF Full-text (1752 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Northern shrimp (Pandalus borealis) oil, which is rich in omega-3 fatty acids, was recovered from the cooking water of shrimp processing facilities. The oil contains significant amounts of omega-3 fatty acids in triglyceride form, along with substantial long-chain monounsaturated fatty acids
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Northern shrimp (Pandalus borealis) oil, which is rich in omega-3 fatty acids, was recovered from the cooking water of shrimp processing facilities. The oil contains significant amounts of omega-3 fatty acids in triglyceride form, along with substantial long-chain monounsaturated fatty acids (MUFAs). It also features natural isomeric forms of astaxanthin, a nutritional carotenoid, which gives the oil a brilliant red color. As part of our efforts in developing value added products from waste streams of the seafood processing industry, we present in this paper a comprehensive characterization of the triacylglycerols (TAGs) and astaxanthin esters that predominate in the shrimp oil by using HPLC-HRMS and MS/MS, as well as 13C-NMR. This approach, in combination with FAME analysis, offers direct characterization of fatty acid molecules in their intact forms, including the distribution of regioisomers in TAGs. The information is important for the standardization and quality control, as well as for differentiation of composition features of shrimp oil, which could be sold as an ingredient in health supplements and functional foods. Full article
(This article belongs to the Special Issue Marine Functional Food)
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Open AccessArticle Amino Acid-Derived Metabolites from the Ascidian Aplidium sp.
Mar. Drugs 2015, 13(6), 3836-3848; https://doi.org/10.3390/md13063836
Received: 21 April 2015 / Accepted: 5 June 2015 / Published: 16 June 2015
Cited by 2 | PDF Full-text (349 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Four new iodobenzene-containing dipeptides (14), a related bromotryptophan-containing dipeptide (5), and an iodophenethylamine (6) were isolated from the ascidian Aplidium sp. collected off the coast of Chuja-do, Korea. The structures of these novel compounds, designated
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Four new iodobenzene-containing dipeptides (14), a related bromotryptophan-containing dipeptide (5), and an iodophenethylamine (6) were isolated from the ascidian Aplidium sp. collected off the coast of Chuja-do, Korea. The structures of these novel compounds, designated as apliamides A–E (15) and apliamine A (6) were determined via combined spectroscopic analyses. The absolute configuration of the amino acid residue in 1 was determined by advanced Marfey’s analysis. Several of these compounds exhibited moderate cytotoxicity and significant inhibition against Na+/K+-ATPase (4). Full article
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Open AccessArticle Dangerous Relations in the Arctic Marine Food Web: Interactions between Toxin Producing Pseudo-nitzschia Diatoms and Calanus Copepodites
Mar. Drugs 2015, 13(6), 3809-3835; https://doi.org/10.3390/md13063809
Received: 5 February 2015 / Accepted: 28 May 2015 / Published: 16 June 2015
Cited by 17 | PDF Full-text (1031 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Diatoms of the genus Pseudo-nitzschia produce domoic acid (DA), a toxin that is vectored in the marine food web, thus causing serious problems for marine organisms and humans. In spite of this, knowledge of interactions between grazing zooplankton and diatoms is restricted. In
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Diatoms of the genus Pseudo-nitzschia produce domoic acid (DA), a toxin that is vectored in the marine food web, thus causing serious problems for marine organisms and humans. In spite of this, knowledge of interactions between grazing zooplankton and diatoms is restricted. In this study, we examined the interactions between Calanus copepodites and toxin producing Pseudo-nitzschia. The copepodites were fed with different concentrations of toxic P. seriata and a strain of P. obtusa that previously was tested to be non-toxic. The ingestion rates did not differ among the diets (P. seriata, P. obtusa, a mixture of both species), and they accumulated 6%–16% of ingested DA (up to 420 µg per dry weight copepodite). When P. seriata was exposed to the copepodites, either through physical contact with the grazers or separated by a membrane, the toxicity of P. seriata increased (up to 3300%) suggesting the response to be chemically mediated. The induced response was also triggered when copepodites grazed on another diatom, supporting the hypothesis that the cues originate from the copepodite. Neither pH nor nutrient concentrations explained the induced DA production. Unexpectedly, P. obtusa also produced DA when exposed to grazing copepodites, thus representing the second reported toxic polar diatom. Full article
(This article belongs to the Special Issue Metabolites in Diatoms)
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Open AccessArticle Functional Genomics of the Aeromonas salmonicida Lipopolysaccharide O-Antigen and A-Layer from Typical and Atypical Strains
Mar. Drugs 2015, 13(6), 3791-3808; https://doi.org/10.3390/md13063791
Received: 14 April 2015 / Accepted: 27 April 2015 / Published: 15 June 2015
Cited by 3 | PDF Full-text (1082 KB) | HTML Full-text | XML Full-text
Abstract
The A. salmonicida A450 LPS O-antigen, encoded by the wbsalmo gene cluster, is exported through an ABC-2 transporter-dependent pathway. It represents the first example of an O-antigen LPS polysaccharide with three different monosaccharides in their repeating unit assembled by this pathway. Until
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The A. salmonicida A450 LPS O-antigen, encoded by the wbsalmo gene cluster, is exported through an ABC-2 transporter-dependent pathway. It represents the first example of an O-antigen LPS polysaccharide with three different monosaccharides in their repeating unit assembled by this pathway. Until now, only repeating units with one or two different monosaccharides have been described. Functional genomic analysis of this wbsalmo region is mostly in agreement with the LPS O-antigen structure of acetylated l-rhamnose (Rha), d-glucose (Glc), and 2-amino-2-deoxy-d-mannose (ManN). Between genes of the wbsalmo we found the genes responsible for the biosynthesis and assembly of the S-layer (named A-layer in these strains). Through comparative genomic analysis and in-frame deletions of some of the genes, we concluded that all the A. salmonicida typical and atypical strains, other than A. salmonicida subsp. pectinolytica strains, shared the same wbsalmo and presence of A-layer. A. salmonicida subsp. pectinolytica strains lack wbsalmo and A-layer, two major virulence factors, and this could be the reason they are the only ones not found as fish pathogens. Full article
(This article belongs to the Special Issue Marine Lipopolysaccharides)
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Open AccessArticle A New Meroditerpene and a New Tryptoquivaline Analog from the Algicolous Fungus Neosartorya takakii KUFC 7898
Mar. Drugs 2015, 13(6), 3776-3790; https://doi.org/10.3390/md13063776
Received: 29 April 2015 / Accepted: 4 June 2015 / Published: 15 June 2015
Cited by 9 | PDF Full-text (367 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A new meroditerpene sartorenol (1), a new natural product takakiamide (2) and a new tryptoquivaline analog (3) were isolated, together with nine known compounds, including aszonapyrone A, chevalone B, aszonalenin, acetylaszonalenin, 3′-(4-oxoquinazolin-3-yl) spiro[1H-indole-3,5′-oxolane]-2,2′-dione, tryptoquivalines L,
[...] Read more.
A new meroditerpene sartorenol (1), a new natural product takakiamide (2) and a new tryptoquivaline analog (3) were isolated, together with nine known compounds, including aszonapyrone A, chevalone B, aszonalenin, acetylaszonalenin, 3′-(4-oxoquinazolin-3-yl) spiro[1H-indole-3,5′-oxolane]-2,2′-dione, tryptoquivalines L, F and H, and the isocoumarin derivative, 6-hydroxymellein, from the ethyl acetate extract of the culture of the algicolous fungus Neosartorya takakii KUFC 7898. The structures of the new compounds were established based on 1D and 2D NMR spectral analysis, and, in the case of sartorenol (1) and tryptoquivaline U (3), X-ray analysis was used to confirm their structures and to determine the absolute configuration of their stereogenic carbons. Compounds 1, 2 and 3 were evaluated for their antimicrobial activity against Gram-positive and Gram-negative bacteria, and multidrug-resistant isolates from the environment; however, none exhibited antibacterial activity (MIC ˃ 256 mg/mL). The three new compounds did not show any quorum sensing inhibition in the screening protocol based on the pigment production by Chromobacterium violaceum (ATCC 31532). Full article
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Open AccessArticle Sulfated Galactan from Palisada flagellifera Inhibits Toxic Effects of Lachesis muta Snake Venom
Mar. Drugs 2015, 13(6), 3761-3775; https://doi.org/10.3390/md13063761
Received: 8 April 2015 / Revised: 20 May 2015 / Accepted: 25 May 2015 / Published: 11 June 2015
Cited by 3 | PDF Full-text (639 KB) | HTML Full-text | XML Full-text
Abstract
In Brazil, snakebites are a public health problem and accidents caused by Lachesis muta have the highest mortality index. Envenomation by L. muta is characterized by systemic (hypotension, bleeding and renal failure) and local effects (necrosis, pain and edema). The treatment to reverse
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In Brazil, snakebites are a public health problem and accidents caused by Lachesis muta have the highest mortality index. Envenomation by L. muta is characterized by systemic (hypotension, bleeding and renal failure) and local effects (necrosis, pain and edema). The treatment to reverse the evolution of all the toxic effects is performed by injection of antivenom. However, such therapy does not effectively neutralize tissue damage or any other local effect, since in most cases victims delay seeking appropriate medical care. In this way, alternative therapies are in demand, and molecules from natural sources have been exhaustively tested. In this paper, we analyzed the inhibitory effect of a sulfated galactan obtained from the red seaweed Palisada flagellifera against some toxic activities of L. muta venom. Incubation of sulfated galactan with venom resulted in inhibition of hemolysis, coagulation, proteolysis, edema and hemorrhage. Neutralization of hemorrhage was also observed when the galactan was administered after or before the venom injection; thus mimicking a real in vivo situation. Moreover, the galactan blocked the edema caused by a phospholipase A2 isolated from the same venom. Therefore, the galactan from P. flagellifera may represent a promising tool to treat envenomation by L. muta as a coadjuvant for the conventional antivenom. Full article
(This article belongs to the Special Issue Marine Secondary Metabolites)
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Open AccessArticle Valorization of Sargassum muticum Biomass According to the Biorefinery Concept
Mar. Drugs 2015, 13(6), 3745-3760; https://doi.org/10.3390/md13063745
Received: 24 March 2015 / Revised: 26 May 2015 / Accepted: 28 May 2015 / Published: 11 June 2015
Cited by 11 | PDF Full-text (402 KB) | HTML Full-text | XML Full-text
Abstract
The biorefinery concept integrates processes and technologies for an efficient biomass conversion using all components of a feedstock. Sargassum muticum is an invasive brown algae which could be regarded as a renewable resource susceptible of individual valorization of the constituent fractions into high
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The biorefinery concept integrates processes and technologies for an efficient biomass conversion using all components of a feedstock. Sargassum muticum is an invasive brown algae which could be regarded as a renewable resource susceptible of individual valorization of the constituent fractions into high added-value compounds. Microwave drying technology can be proposed before conventional ethanol extraction of algal biomass, and supercritical fluid extraction with CO2 was useful to extract fucoxanthin and for the fractionation of crude ethanol extracts. Hydrothermal processing is proposed to fractionate the algal biomass and to solubilize the fucoidan and phlorotannin fractions. Membrane technology was proposed to concentrate these fractions and obtain salt- and arsenic-free saccharidic fractions. Based on these technologies, this study presents a multipurpose process to obtain six different products with potential applications for nutraceutical, cosmetic and pharmaceutical industries. Full article
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Open AccessArticle Use of Natural Antimicrobial Peptides and Bacterial Biopolymers for Cultured Pearl Production
Mar. Drugs 2015, 13(6), 3732-3744; https://doi.org/10.3390/md13063732
Received: 5 March 2015 / Revised: 20 May 2015 / Accepted: 27 May 2015 / Published: 11 June 2015
Cited by 5 | PDF Full-text (2686 KB) | HTML Full-text | XML Full-text
Abstract
Cultured pearls are the product of grafting and rearing of Pinctada margaritifera pearl oysters in their natural environment. Nucleus rejections and oyster mortality appear to result from bacterial infections or from an inappropriate grafting practice. To reduce the impact of bacterial infections, synthetic
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Cultured pearls are the product of grafting and rearing of Pinctada margaritifera pearl oysters in their natural environment. Nucleus rejections and oyster mortality appear to result from bacterial infections or from an inappropriate grafting practice. To reduce the impact of bacterial infections, synthetic antibiotics have been applied during the grafting practice. However, the use of such antibiotics presents a number of problems associated with their incomplete biodegradability, limited efficacy in some cases, and an increased risk of selecting for antimicrobial resistant bacteria. We investigated the application of a marine antimicrobial peptide, tachyplesin, which is present in the Japanese horseshoe crab Tachypleus tridentatus, in combination with two marine bacterial exopolymers as alternative treatment agents. In field studies, the combination treatment resulted in a significant reduction in graft failures vs. untreated controls. The combination of tachyplesin (73 mg/L) with two bacterial exopolysaccharides (0.5% w/w) acting as filming agents, reduces graft-associated bacterial contamination. The survival data were similar to that reported for antibiotic treatments. These data suggest that non-antibiotic treatments of pearl oysters may provide an effective means of improving oyster survival following grafting procedures. Full article
(This article belongs to the Special Issue Marine Peptides and Their Mimetics)
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Open AccessArticle Extraction, Isolation, Structural Characterization and Anti-Tumor Properties of an Apigalacturonan-Rich Polysaccharide from the Sea Grass Zostera caespitosa Miki
Mar. Drugs 2015, 13(6), 3710-3731; https://doi.org/10.3390/md13063710
Received: 1 April 2015 / Revised: 19 May 2015 / Accepted: 21 May 2015 / Published: 11 June 2015
Cited by 5 | PDF Full-text (4191 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
An apigalacturonan (AGA)-rich polysaccharide, ZCMP, was isolated from the sea grass Zostera caespitosa Miki. The depolymerized fragments derived from ZCMP were obtained by either acidic degradation or pectinase degradation, and their structures were characterized by electrospray ionization collision-induced-dissociation mass spectrometry (ESI-CID-MS2) and nuclear
[...] Read more.
An apigalacturonan (AGA)-rich polysaccharide, ZCMP, was isolated from the sea grass Zostera caespitosa Miki. The depolymerized fragments derived from ZCMP were obtained by either acidic degradation or pectinase degradation, and their structures were characterized by electrospray ionization collision-induced-dissociation mass spectrometry (ESI-CID-MS2) and nuclear magnetic resonance (NMR) spectroscopy. The average molecular weight of ZCMP was 77.2 kD and it consisted of galacturonic acid (GalA), apiosefuranose (Api), galactose (Gal), rhamnose (Rha), arabinose (Ara), xylose (Xyl), and mannose (Man), at a molar ratio of 51.4꞉15.5꞉6.0꞉11.8꞉4.2꞉4.4꞉4.2. There were two regions of AGA (70%) and rhamnogalacturonan-I (RG-Ι, 30%) in ZCMP. AGA was composed of an α-1,4-D-galactopyranosyluronan backbone mainly substituted at the O-3 position by single Api residues. RG-Ι possessed a backbone of repeating disaccharide units of →4GalAα1,2Rhaα1→, with a few α-L-arabinose and β-D-galactose residues as side chains. The anti-angiogenesis assay showed that ZCMP inhibited the migratory activity of human umbilical vein endothelial cell (HUVECs), with no influence on endothelial cells growth. ZCMP also promoted macrophage phagocytosis. These findings of the present study demonstrated the potential anti-tumor activity of ZCMP through anti-angiogenic and immunoregulatory pathways. Full article
(This article belongs to the Special Issue Marine Glycoconjugates)
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Open AccessReview Low-Molecular-Weight Metabolites from Diatoms: Structures, Biological Roles and Biosynthesis
Mar. Drugs 2015, 13(6), 3672-3709; https://doi.org/10.3390/md13063672
Received: 12 February 2015 / Revised: 5 May 2015 / Accepted: 14 May 2015 / Published: 9 June 2015
Cited by 18 | PDF Full-text (844 KB) | HTML Full-text | XML Full-text
Abstract
Diatoms are abundant and important biological components of the marine environment that biosynthesize diverse natural products. These microalgae are rich in various lipids, carotenoids, sterols and isoprenoids, some of them containing toxins and other metabolites. Several groups of diatom natural products have attracted
[...] Read more.
Diatoms are abundant and important biological components of the marine environment that biosynthesize diverse natural products. These microalgae are rich in various lipids, carotenoids, sterols and isoprenoids, some of them containing toxins and other metabolites. Several groups of diatom natural products have attracted great interest due to their potential practical application as energy sources (biofuel), valuable food constituents, and prospective materials for nanotechnology. In addition, hydrocarbons, which are used in climate reconstruction, polyamines which participate in biomineralization, new apoptotic agents against tumor cells, attractants and deterrents that regulate the biochemical communications between marine species in seawaters have also been isolated from diatoms. However, chemical studies on these microalgae are complicated by difficulties, connected with obtaining their biomass, and the influence of nutrients and contaminators in their environment as well as by seasonal and climatic factors on the biosynthesis of the corresponding natural products. Overall, the number of chemically studied diatoms is lower than that of other algae, but further studies, particularly those connected with improvements in the isolation and structure elucidation technique as well as the genomics of diatoms, promise both to increase the number of studied species with isolated biologically active natural products and to provide a clearer perception of their biosynthesis. Full article
(This article belongs to the Special Issue Metabolites in Diatoms)
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