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Mar. Drugs, Volume 9, Issue 1 (January 2011) – 10 articles , Pages 1-153

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360 KiB  
Article
Sulfated Polysaccharides in Marine Sponges: Extraction Methods and Anti-HIV Activity
by Ana I. S. Esteves, Marisa Nicolai, Madalena Humanes and Joao Goncalves
Mar. Drugs 2011, 9(1), 139-153; https://doi.org/10.3390/md9010139 - 24 Jan 2011
Cited by 34 | Viewed by 10611
Abstract
The extraction, fractionation and HIV-1 inhibition potential of polysaccharides extracted from three species of marine sponges, Erylus discophorus, Cliona celata and Stelletta sp., collected in the Northeastern Atlantic, is presented in this work. The anti-HIV activity of 23 polysaccharide pellets and three [...] Read more.
The extraction, fractionation and HIV-1 inhibition potential of polysaccharides extracted from three species of marine sponges, Erylus discophorus, Cliona celata and Stelletta sp., collected in the Northeastern Atlantic, is presented in this work. The anti-HIV activity of 23 polysaccharide pellets and three crude extracts was tested. Crude extracts prepared from Erylus discophorus specimens were all highly active against HIV-1 (90 to 95% inhibition). Cliona celata pellets showed low polysaccharide content (bellow 38.5%) and almost no anti-HIV activity (<10% inhibition). Stelletta sp. pellets, although quite rich in polysaccharide (up to 97.3%), showed only modest bioactivity (<36% HIV-1 inhibition). Erylus discophorus pellets were among the richest in terms of polysaccharide content (up to 98%) and the most active against HIV-1 (up to 95% inhibition). Chromatographic fractionation of the polysaccharide pellet obtained from a specimen of Erylus discophorus (B161) yielded only modestly active fractions. However, we could infer that the active molecule is most probably a high molecular weight sulfated polysaccharide (>2000 kDa), whose mechanism is possibly preventing viral attachment and entry (fusion inhibitor). Full article
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500 KiB  
Article
Heterofucans from the Brown Seaweed Canistrocarpus cervicornis with Anticoagulant and Antioxidant Activities
by Rafael Barros Gomes Camara, Leandro Silva Costa, Gabriel Pereira Fidelis, Leonardo Thiago Duarte Barreto Nobre, Nednaldo Dantas-Santos, Sara Lima Cordeiro, Mariana Santana Santos Pereira Costa, Luciana Guimaraes Alves and Hugo Alexandre Oliveira Rocha
Mar. Drugs 2011, 9(1), 124-138; https://doi.org/10.3390/md9010124 - 24 Jan 2011
Cited by 123 | Viewed by 13183
Abstract
Fucan is a term used to denominate a family of sulfated polysaccharides rich in sulfated L-fucose. We extracted six fucans from Canistrocarpus cervicornis by proteolytic digestion followed by sequential acetone precipitation. These heterofucans are composed mainly of fucose, glucuronic acid, galactose and sulfate. [...] Read more.
Fucan is a term used to denominate a family of sulfated polysaccharides rich in sulfated L-fucose. We extracted six fucans from Canistrocarpus cervicornis by proteolytic digestion followed by sequential acetone precipitation. These heterofucans are composed mainly of fucose, glucuronic acid, galactose and sulfate. No polysaccharide was capable of prolonging prothrombin time (PT) at the concentration assayed. However, all polysaccharides prolonged activated partial thromboplastin time (aPTT). Four sulfated polysaccharides (CC-0.3/CC-0.5/CC-0.7/CC-1.0) doubled aPTT with only 0.1 mg/mL of plasma, only 1.25-fold less than Clexane®, a commercial low molecular weight heparin. Heterofucans exhibited total antioxidant capacity, low hydroxyl radical scavenging activity, good superoxide radical scavenging efficiency (except CC-1.0), and excellent ferrous chelating ability (except CC-0.3). These results clearly indicate the beneficial effect of C. cervicornis polysaccharides as anticoagulants and antioxidants. Further purification steps and additional studies on structural features as well as in vivo experiments are needed to test the viability of their use as therapeutic agents. Full article
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529 KiB  
Article
Purification and Characterization of a Bifunctional Alginate Lyase from Pseudoalteromonas sp. SM0524
by Jian-Wei Li, Sheng Dong, Jie Song, Chun-Bo Li, Xiu-Lan Chen, Bin-Bin Xie and Yu-Zhong Zhang
Mar. Drugs 2011, 9(1), 109-123; https://doi.org/10.3390/md9010109 - 21 Jan 2011
Cited by 96 | Viewed by 13065
Abstract
An alginate lyase-producing bacterial strain, Pseudoalteromonas sp. SM0524, was screened from marine rotten kelp. In an optimized condition, the production of alginate lyase from Pseudoalteromonas sp. SM0524 reached 62.6 U/mL, suggesting that strain SM0524 is a good producer of alginate lyases. The bifunctional [...] Read more.
An alginate lyase-producing bacterial strain, Pseudoalteromonas sp. SM0524, was screened from marine rotten kelp. In an optimized condition, the production of alginate lyase from Pseudoalteromonas sp. SM0524 reached 62.6 U/mL, suggesting that strain SM0524 is a good producer of alginate lyases. The bifunctional alginate lyasealy-SJ02 secreted by strain SM0524 was purified. Aly-SJ02 had an apparent molecular mass of 32 kDa. The optimal temperature and pH of aly-SJ02 toward sodium alginate was 50 °C and 8.5, respectively. The half life period of aly-SJ02 was 41 min at 40 °C and 20 min at 50 °C. Aly-SJ02 was most stable at pH 8.0. N-terminal sequence analysis suggested that aly-SJ02 may be an alginate lyase of polysaccharide lyase family 18. Aly-SJ02 showed activities toward both polyG (α-L-guluronic acid) and polyM (β-D-mannuronic acid), indicating that it is a bifunctional alginate lyase. Aly-SJ02 had lower Km toward polyG than toward polyM and sodium alginate. Thin layer chromatography and ESI-MS analyses showed that aly-SJ02 mainly released dimers and trimers from polyM and alginate, and trimers and tetramers from polyG, which suggests that aly-SJ02 may be a good tool to produce dimers and trimers from alginate. Full article
(This article belongs to the Special Issue Enzymes from the Sea: Sources, Molecular Biology and Bioprocesses)
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Article
Levantilides A and B, 20-Membered Macrolides from a Micromonospora Strain Isolated from the Mediterranean Deep Sea Sediment
by Andrea Gärtner, Birgit Ohlendorf, Dirk Schulz, Heidi Zinecker, Jutta Wiese and Johannes F. Imhoff
Mar. Drugs 2011, 9(1), 98-108; https://doi.org/10.3390/md9010098 - 14 Jan 2011
Cited by 37 | Viewed by 10093
Abstract
Two new 20-membered macrolides, levantilide A and B, were isolated from the Micromonospora strain M71-A77. Strain M71-A77 was recovered from an Eastern Mediterranean deep-sea sediment sample and revealed to produce the levantilides under in situ salinity of 38.6‰. The chemical structures of the [...] Read more.
Two new 20-membered macrolides, levantilide A and B, were isolated from the Micromonospora strain M71-A77. Strain M71-A77 was recovered from an Eastern Mediterranean deep-sea sediment sample and revealed to produce the levantilides under in situ salinity of 38.6‰. The chemical structures of the levantilides were elucidated on the basis of different one- and two- dimensional NMR experiments. Levantilide A exhibits a moderate antiproliferative activity against several tumor cell lines. Full article
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323 KiB  
Article
Search for Hydrophilic Marine Fungal Metabolites: A Rational Approach for Their Production and Extraction in a Bioactivity Screening Context
by Carine Le Ker, Karina-Ethel Petit, Jean-François Biard and Joël Fleurence
Mar. Drugs 2011, 9(1), 82-97; https://doi.org/10.3390/md9010082 - 10 Jan 2011
Cited by 12 | Viewed by 9085
Abstract
In the search for bioactive natural products, our lab screens hydrophobic extracts from marine fungal strains. While hydrophilic active substances were recently identified from marine macro-organisms, there was a lack of reported metabolites in the marine fungi area. As such, we decided to [...] Read more.
In the search for bioactive natural products, our lab screens hydrophobic extracts from marine fungal strains. While hydrophilic active substances were recently identified from marine macro-organisms, there was a lack of reported metabolites in the marine fungi area. As such, we decided to develop a general procedure for screening of hydrophobic metabolites. The aim of this study was to compare different processes of fermentation and extraction, using six representative marine fungal strains, in order to define the optimized method for production. The parameters studied were (a) which polar solvent to select, (b) which fermentation method to choose between solid and liquid cultures, (c) which raw material, the mycelium or its medium, to extract and (d) which extraction process to apply. The biochemical analysis and biological evaluations of obtained extracts led to the conclusion that the culture of marine fungi by agar surface fermentation followed by the separate extraction of the mycelium and its medium by a cryo-crushing and an enzymatic digestion with agarase, respectively, was the best procedure when screening for hydrophilic bioactive metabolites. During this development, several bioactivities were detected, confirming the potential of hydrophilic crude extracts in the search for bioactive natural products. Full article
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223 KiB  
Article
Toward the Synthesis and Biological Screening of a Cyclotetrapeptide from Marine Bacteria
by Rajiv Dahiya and Hemendra Gautam
Mar. Drugs 2011, 9(1), 71-81; https://doi.org/10.3390/md9010071 - 30 Dec 2010
Cited by 30 | Viewed by 9373
Abstract
The first synthesis of a naturally occurring tetrapeptide cyclo-(isoleucyl-prolyl-leucyl-alanyl) has been achieved using a solution-phase technique via coupling of dipeptide segments Boc-l-Pro-l-Leu-OH and l-Ala-l-Ile-OMe. Deprotection of the linear tetrapeptide unit and its subsequent cyclization gave a cyclopeptide, identical in all aspects to [...] Read more.
The first synthesis of a naturally occurring tetrapeptide cyclo-(isoleucyl-prolyl-leucyl-alanyl) has been achieved using a solution-phase technique via coupling of dipeptide segments Boc-l-Pro-l-Leu-OH and l-Ala-l-Ile-OMe. Deprotection of the linear tetrapeptide unit and its subsequent cyclization gave a cyclopeptide, identical in all aspects to the naturally occurring compound. Bioactivity results indicated the antifungal and antihelmintic potential of the synthesized peptide against pathogenic dermatophytes and earthworms. Full article
(This article belongs to the Special Issue Marine Peptides)
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225 KiB  
Article
Secondary Metabolites from a Marine-Derived Endophytic Fungus Penicillium chrysogenum QEN-24S
by Shu-Shan Gao, Xiao-Ming Li, Feng-Yu Du, Chun-Shun Li, Peter Proksch and Bin-Gui Wang
Mar. Drugs 2011, 9(1), 59-70; https://doi.org/10.3390/md9010059 - 27 Dec 2010
Cited by 91 | Viewed by 15826
Abstract
Penicillium chrysogenum QEN-24S, an endophytic fungus isolated from an unidentified marine red algal species of the genus Laurencia, displayed inhibitory activity against the growth of pathogen Alternaria brassicae in dual culture test. Chemical investigation of this fungal strain resulted in the isolation [...] Read more.
Penicillium chrysogenum QEN-24S, an endophytic fungus isolated from an unidentified marine red algal species of the genus Laurencia, displayed inhibitory activity against the growth of pathogen Alternaria brassicae in dual culture test. Chemical investigation of this fungal strain resulted in the isolation of four new (13 and 5) and one known (4) secondary metabolites. Their structures were identified as two polyketide derivatives penicitides A and B (1 and 2), two glycerol derivatives 2-(2,4-dihydroxy-6-methylbenzoyl)-glycerol (3) and 1-(2,4-dihydroxy-6-methylbenzoyl)-glycerol (4), and one monoterpene derivative penicimonoterpene (5). Penicitides A and B (1 and 2) feature a unique 10-hydroxy- or 7,10-dihydroxy-5,7-dimethylundecyl moiety substituting at C-5 of the α-tetrahydropyrone ring, which is not reported previously among natural products. Compound 5 displayed potent activity against the pathogen A. brassicae, while compound 1 exhibited moderate cytotoxic activity against the human hepatocellular liver carcinoma cell line. Full article
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320 KiB  
Article
Low Water Activity Induces the Production of Bioactive Metabolites in Halophilic and Halotolerant Fungi
by Kristina Sepcic, Polona Zalar and Nina Gunde-Cimerman
Mar. Drugs 2011, 9(1), 43-58; https://doi.org/10.3390/md9010043 - 27 Dec 2010
Cited by 43 | Viewed by 11450
Abstract
The aim of the present study was to investigate indigenous fungal communities isolated from extreme environments (hypersaline waters of solar salterns and subglacial ice), for the production of metabolic compounds with selected biological activities: hemolysis, antibacterial, and acetylcholinesterase inhibition. In their natural habitats, [...] Read more.
The aim of the present study was to investigate indigenous fungal communities isolated from extreme environments (hypersaline waters of solar salterns and subglacial ice), for the production of metabolic compounds with selected biological activities: hemolysis, antibacterial, and acetylcholinesterase inhibition. In their natural habitats, the selected fungi are exposed to environmental extremes, and therefore the production of bioactive metabolites was tested under both standard growth conditions for mesophilic microorganisms, and at high NaCl and sugar concentrations and low growth temperatures. The results indicate that selected halotolerant and halophilic species synthesize specific bioactive metabolites under conditions that represent stress for non-adapted species. Furthermore, adaptation at the level of the chemical nature of the solute lowering the water activity of the medium was observed. Increased salt concentrations resulted in higher hemolytic activity, particularly within species dominating the salterns. The appearance of antibacterial potential under stress conditions was seen in the similar pattern of fungal species as for hemolysis. The active extracts exclusively affected the growth of the Gram-positive bacterium tested, Bacillus subtilis. None of the extracts tested showed inhibition of acetylcholinesterase activity. Full article
(This article belongs to the Special Issue Bioactive Compounds from Marine Fungi)
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579 KiB  
Article
Enhanced Productivity of a Lutein-Enriched Novel Acidophile Microalga Grown on Urea
by Carlos Casal, Maria Cuaresma, Jose Maria Vega and Carlos Vilchez
Mar. Drugs 2011, 9(1), 29-42; https://doi.org/10.3390/md9010029 - 24 Dec 2010
Cited by 70 | Viewed by 13547
Abstract
Coccomyxa acidophila is an extremophile eukaryotic microalga isolated from the Tinto River mining area in Huelva, Spain. Coccomyxa acidophila accumulates relevant amounts of b-carotene and lutein, well-known carotenoids with many biotechnological applications, especially in food and health-related industries. The acidic culture medium (pH [...] Read more.
Coccomyxa acidophila is an extremophile eukaryotic microalga isolated from the Tinto River mining area in Huelva, Spain. Coccomyxa acidophila accumulates relevant amounts of b-carotene and lutein, well-known carotenoids with many biotechnological applications, especially in food and health-related industries. The acidic culture medium (pH < 2.5) that prevents outdoor cultivation from non-desired microorganism growth is one of the main advantages of acidophile microalgae production. Conversely, acidophile microalgae growth rates are usually very low compared to common microalgae growth rates. In this work, we show that mixotrophic cultivation on urea efficiently enhances growth and productivity of an acidophile microalga up to typical values for common microalgae, therefore approaching acidophile algal production towards suitable conditions for feasible outdoor production. Algal productivity and potential for carotenoid accumulation were analyzed as a function of the nitrogen source supplied. Several nitrogen conditions were assayed: nitrogen starvation, nitrate and/or nitrite, ammonia and urea. Among them, urea clearly led to the best cell growth (~4 ´ 108 cells/mL at the end of log phase). Ammonium led to the maximum chlorophyll and carotenoid content per volume unit (220 mg·mL-1 and 35 mg·mL-1, respectively). Interestingly, no significant differences in growth rates were found in cultures grown on urea as C and N source, with respect to those cultures grown on nitrate and CO2 as nitrogen and carbon sources (control cultures). Lutein accumulated up to 3.55 mg·g-1 in the mixotrophic cultures grown on urea. In addition, algal growth in a shaded culture revealed the first evidence for an active xanthophylls cycle operative in acidophile microalgae. Full article
(This article belongs to the Special Issue Marine Carotenoids (Special Issue))
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800 KiB  
Article
Isolation and Characterization of a Mn(II)-Oxidizing Bacillus Strain from the Demosponge Suberites domuncula
by Xiaohong Wang, Matthias Wiens, Mugdha Divekar, Vladislav A. Grebenjuk, Heinz C. Schröder, Renato Batel and Werner E. G. Müller
Mar. Drugs 2011, 9(1), 1-28; https://doi.org/10.3390/md9010001 - 23 Dec 2010
Cited by 21 | Viewed by 10255
Abstract
In this study we demonstrate that the demosponge Suberites domuncula harbors a Mn(II)-oxidizing bacterium, a Bacillus strain, termed BAC-SubDo-03. Our studies showed that Mn(II) stimulates bacterial growth and induces sporulation. Moreover, we show that these bacteria immobilize manganese on their cell surface. Comparison [...] Read more.
In this study we demonstrate that the demosponge Suberites domuncula harbors a Mn(II)-oxidizing bacterium, a Bacillus strain, termed BAC-SubDo-03. Our studies showed that Mn(II) stimulates bacterial growth and induces sporulation. Moreover, we show that these bacteria immobilize manganese on their cell surface. Comparison of the 16S rDNA sequence allowed the grouping of BAC-SubDo-03 to the Mn-precipitating bacteria. Analysis of the spore cell wall revealed that it contains an Mn(II)-oxidizing enzyme. Co-incubation studies of BAC-SubDo-03 with 100 µM MnCl2 and >1 µM of CuCl2 showed an increase in their Mn(II)-oxidizing capacity. In order to prove that a multicopper oxidase-like enzyme(s) (MCO) exists in the cell wall of the S. domuncula-associated BAC‑SubDo-03 Bacillus strain, the gene encoding this enzyme was cloned (mnxG‑SubDo‑03). Sequence alignment of the deduced MCO protein (MnxG-SubDo-03) revealed that the sponge bacterium clusters together with known Mn(II)-oxidizing bacteria. The expression of the mnxG-SubDo-03 gene is under strong control of extracellular Mn(II). Based on these findings, we assume that BAC-SubDo-03 might serve as a Mn reserve in the sponge providing the animal with the capacity to detoxify Mn in the environment. Applying the in vitro primmorph cell culture system we could demonstrate that sponge cells, that were co-incubated with BAC-SubDo-03 in the presence of Mn(II), show an increased proliferation potential. Full article
(This article belongs to the Special Issue Biosynthesis of Marine Natural Products)
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