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Mar. Drugs, Volume 8, Issue 4 (April 2010), Pages 835-1481

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Research

Jump to: Review

Open AccessArticle Leucine Aminopeptidase, β-Glucosidase and Alkaline Phosphatase Activity Rates and Their Significance in Nutrient Cycles in Some Coastal Mediterranean Sites
Mar. Drugs 2010, 8(4), 916-940; doi:10.3390/md8040916
Received: 20 February 2010 / Revised: 19 March 2010 / Accepted: 26 March 2010 / Published: 29 March 2010
Cited by 13 | PDF Full-text (466 KB) | HTML Full-text | XML Full-text
Abstract
In aquatic microbial ecology, knowledge of the processes involved in the turnover of organic matter is of utmost importance to understand ecosystem functioning. Microorganisms are major players in the cycling of nutrients (nitrogen, phosphorus) and carbon, thanks to their enzymatic activities (leucine aminopeptidase,
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In aquatic microbial ecology, knowledge of the processes involved in the turnover of organic matter is of utmost importance to understand ecosystem functioning. Microorganisms are major players in the cycling of nutrients (nitrogen, phosphorus) and carbon, thanks to their enzymatic activities (leucine aminopeptidase, LAP, alkaline phosphatase, AP, and β-glucosidase, β-GLU) on organic polymers (proteins, organic phosphates and polysaccharides, respectively). Estimates of the decomposition rates of organic polymers are performed using fluorogenic compounds, whose hydrolysis rate allow us to obtain information on the “potential” metabolic activity of the prokaryotic community. This paper refers the enzyme patterns measured during recent oceanographic cruises performed in some coastal Mediterranean sites, not yet fully investigated in terms of microbial biogeochemical processes. Mean enzyme activity rates ranged from 5.24 to 5558.1 nM/h, from 12.68 to 244.73 nM/h and from 0.006 to 9.51 nM/h for LAP, AP and β-GLU, respectively. The highest LAP and AP activity rates were measured in the Gulf of Milazzo (Tyrrhenian Sea) and in the Straits of Messina, in association with the lowest bacterioplankton abundance; in contrast, the lowest ones were found in the northern Adriatic Sea. β-GLU was more active in the Straits of Messina. Activity rates were analysed in relation to the main environmental variables. Along the northern Adriatic coastal side affected by the Po river, significant inverse relationships linked LAP and AP with salinity, pointing out that fluvial inputs provided organic substrates for microbial metabolism. Both in the Gulf of Manfredonia and in the Straits of Messina, LAP and AP levels were inversely related with the concentration of nitrate and inorganic phosphorus, respectively. In the Gulf of Milazzo, high cell-specific AP measured in spite of phosphorus availability suggested the role of this enzyme not only in phosphorus, but also in carbon release. Full article
(This article belongs to the Special Issue Enzymes from the Sea: Sources, Molecular Biology and Bioprocesses)
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Open AccessArticle Five Sesquiterpenoids from a Marine-Derived Fungus Aspergillus sp. Isolated from a Gorgonian Dichotella gemmacea
Mar. Drugs 2010, 8(4), 941-949; doi:10.3390/md8040941
Received: 4 March 2010 / Revised: 17 March 2010 / Accepted: 26 March 2010 / Published: 29 March 2010
Cited by 43 | PDF Full-text (215 KB) | HTML Full-text | XML Full-text
Abstract
Three new phenolic bisabolane-type sesquiterpenoids: (+)-methyl sydowate (1), 7-deoxy-7,14-didehydrosydonic acid (2), and 7-deoxy-7,8-didehydrosydonic acid (3), together with two known fungal metabolites were isolated from the fermentation broth of a marine-derived fungus Aspergillus sp., which was isolated in
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Three new phenolic bisabolane-type sesquiterpenoids: (+)-methyl sydowate (1), 7-deoxy-7,14-didehydrosydonic acid (2), and 7-deoxy-7,8-didehydrosydonic acid (3), together with two known fungal metabolites were isolated from the fermentation broth of a marine-derived fungus Aspergillus sp., which was isolated in turn from a gorgonian Dichotella gemmacea collected from the South China Sea. Their structures were elucidated by combined spectroscopic methods, and the structure of 1 was further confirmed by single-crystal X-ray data. Full article
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Open AccessArticle Teratogenic Effects of Diatom Metabolites on Sea Urchin Paracentrotus lividus Embryos
Mar. Drugs 2010, 8(4), 950-967; doi:10.3390/md8040950
Received: 24 February 2010 / Revised: 6 March 2010 / Accepted: 24 March 2010 / Published: 30 March 2010
Cited by 33 | PDF Full-text (440 KB) | HTML Full-text | XML Full-text
Abstract
The diatom-derived polyunsaturated aldehydes (PUAs), 2-trans,4-trans-decadienal, 2-trans,4-trans-octadienal, 2-trans,4-trans,7-octatrienal, 2-trans,4-trans-heptadienal, as well as tridecanal were tested on early and later larval development in the sea urchin Paracentrotus lividus
[...] Read more.
The diatom-derived polyunsaturated aldehydes (PUAs), 2-trans,4-trans-decadienal, 2-trans,4-trans-octadienal, 2-trans,4-trans,7-octatrienal, 2-trans,4-trans-heptadienal, as well as tridecanal were tested on early and later larval development in the sea urchin Paracentrotus lividus. We also tested the effect of some of the more abundant diatom polyunsaturated fatty acids (PUFAs) on development, in particular 5,8,11,14,17-eicosapentaenoic acid (EPA), one of the main precursors of diatom PUAs, as well as 4,7,10,13,16,19-docosahexaenoic acid (DHA), 6,9,12,15-octadecatetraenoic acid (stearidonic acid), 6,9,12-octadecatrienoic acid (γ-linolenic acid) and 9,12-octadecadienoic acid (linoleic acid). PUAs blocked sea urchin cell cleavage in a dose dependent manner and with increasing chain length from C7 to C10 PUAs, with arrest occurring at 27.27 µM with heptadienal, 16.13 µM with octadienal, 11.47 µM with octatrienal and 5.26 mM with decadienal. Of the PUFAs tested, only EPA and stearidonic acid blocked cleavage, but at much higher concentrations compared to PUAs (331 μM for EPA and 181 μM for stearidonic acid). Sub-lethal concentrations of decadienal (1.32–5.26 μM) delayed development of embryos and larvae which showed various degrees of malformations depending on the concentrations tested. Sub-lethal concentrations also increased the proportion of TUNEL-positive cells indicating imminent death in embryos and larvae. Using decadienal as a model PUA, we show that this aldehyde can be detected spectrophotometrically for up to 14 days in f/2 medium. Full article
(This article belongs to the Special Issue Marine Bioactive Compounds Acting on Animal Reproduction)
Open AccessArticle LC/MS Analysis of Tetrodotoxin and Its Deoxy Analogs in the Marine Puffer Fish Fugu niphobles from the Southern Coast of Korea, and in the Brackishwater Puffer Fishes Tetraodon nigroviridis and Tetraodon biocellatus from Southeast Asia
Mar. Drugs 2010, 8(4), 1049-1058; doi:10.3390/md8041049
Received: 9 February 2010 / Revised: 23 March 2010 / Accepted: 29 March 2010 / Published: 31 March 2010
Cited by 28 | PDF Full-text (264 KB) | HTML Full-text | XML Full-text
Abstract
Tetrodotoxin (TTX) and its deoxy analogs, 5-deoxyTTX, 11-deoxyTTX, 6,11-dideoxyTTX, and 5,6,11-trideoxyTTX, were quantified in the tissues of three female and three male specimens of the marine puffer fish, Fugu niphobles, from the southern coast of Korea, and in the whole body of the
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Tetrodotoxin (TTX) and its deoxy analogs, 5-deoxyTTX, 11-deoxyTTX, 6,11-dideoxyTTX, and 5,6,11-trideoxyTTX, were quantified in the tissues of three female and three male specimens of the marine puffer fish, Fugu niphobles, from the southern coast of Korea, and in the whole body of the brackishwater puffer fishes, Tetraodon nigroviridis (12 specimens) and Tetrodon biocellatus (three specimens) from Southeast Asia using LC/MS in single ion mode (SIM). Identification of these four deoxy analogs in the ovarian tissue of F. niphobles were further confirmed by LC/MS/MS. TTX and 5,6,11-trideoxyTTX were detected in all three puffer fish species as the major TTX analogs, similar to Japanese Fugu pardalis. While 6,11-dideoxyTTX was also found to be a major analog in almost all tissues of Korean F. niphobles, this analog was minor in the two Tetraodon species and Japanese F. pardalis. Among the tissues of F. niphobles, the concentrations of TTXs were highest in the ovaries (female) and skin (female and male). Full article
(This article belongs to the Special Issue Tetrodotoxin)
Open AccessArticle Anticancer Effect and Structure-Activity Analysis of Marine Products Isolated from Metabolites of Mangrove Fungi in the South China Sea
Mar. Drugs 2010, 8(4), 1094-1105; doi:10.3390/md8041094
Received: 21 January 2010 / Revised: 22 March 2010 / Accepted: 30 March 2010 / Published: 1 April 2010
Cited by 14 | PDF Full-text (770 KB) | HTML Full-text | XML Full-text
Abstract
Marine-derived fungi provide plenty of structurally unique and biologically active secondary metabolites. We screened 87 marine products from mangrove fungi in the South China Sea for anticancer activity by MTT assay. 14% of the compounds (11/86) exhibited a potent activity against cancer in
[...] Read more.
Marine-derived fungi provide plenty of structurally unique and biologically active secondary metabolites. We screened 87 marine products from mangrove fungi in the South China Sea for anticancer activity by MTT assay. 14% of the compounds (11/86) exhibited a potent activity against cancer in vitro. Importantly, some compounds such as compounds 78 and 81 appeared to be promising for treating cancer patients with multidrug resistance, which should encourage more efforts to isolate promising candidates for further development as clinically useful chemotherapeutic drugs. Furthermore, DNA intercalation was not involved in their anticancer activities, as determined by DNA binding assay. On the other hand, the structure-activity analysis indicated that the hydroxyl group was important for their cytotoxic activity and that bulky functional groups such as phenyl rings could result in a loss of biological activity, which will direct the further development of marine product-based derivatives. Full article
Open AccessArticle Carrageenans as a New Source of Drugs with Metal Binding Properties
Mar. Drugs 2010, 8(4), 1106-1121; doi:10.3390/md8041106
Received: 26 February 2010 / Revised: 16 March 2010 / Accepted: 29 March 2010 / Published: 1 April 2010
Cited by 10 | PDF Full-text (820 KB) | HTML Full-text | XML Full-text
Abstract
Carrageenans are abundant and safe non-starch polysaccharides exerting their biological effects in living organisms. Apart from their known pro-inflammation properties and some pharmacological activity, carrageenans can also strongly bind and hold metal ions. This property can be used for creation of the new
[...] Read more.
Carrageenans are abundant and safe non-starch polysaccharides exerting their biological effects in living organisms. Apart from their known pro-inflammation properties and some pharmacological activity, carrageenans can also strongly bind and hold metal ions. This property can be used for creation of the new drugs for elimination of metals from the body or targeted delivery of these metal ions for healing purposes. Metal binding activity of different carrageenans in aqueous solutions containing Y3+ or Pb2+ ions was studied in a batch sorption system. The metal uptake by carrageenans is not affected by the change of the pH within the range from 2.0 to 6.0. The rates and binding capacities of carrageenans regarding metal ions were evaluated. The Langmuir, Freundlich and BET sorption models were applied to describe the isotherms and constants, and the sorption isothermal data could be explained well by the Langmuir equation. The results obtained through the study suggest that κ-, ι-, and λ-carrageenans are favorable sorbents. The largest amount of Y3+ and Pb2+ ions are bound by i-carrageenan. Therefore, it can be concluded that this type of polysaccharide is the more appropriate substance for elaboration of the drugs with high selective metal binding properties. Full article
Open AccessArticle Studies on Polyethers Produced by Red Algae
Mar. Drugs 2010, 8(4), 1178-1188; doi:10.3390/md8041178
Received: 21 February 2010 / Revised: 8 March 2010 / Accepted: 22 March 2010 / Published: 7 April 2010
Cited by 14 | PDF Full-text (387 KB) | HTML Full-text | XML Full-text
Abstract
Two novel squalene-derived triterpenes, spirodehydrovenustatriol (3) and 14-keto-dehydrothyrsiferol (4) were isolated from the red alga Laurencia viridis, together with two new and unusual C17 terpenoids, adejen A (5) and B (6). These truncated
[...] Read more.
Two novel squalene-derived triterpenes, spirodehydrovenustatriol (3) and 14-keto-dehydrothyrsiferol (4) were isolated from the red alga Laurencia viridis, together with two new and unusual C17 terpenoids, adejen A (5) and B (6). These truncated structures possess structural similarities with other known squalene metabolites and their biogenetic origin has been proposed on the basis of an oxidative process of the squalene skeleton. All the structures were elucidated by extensive use of 2D NMR spectroscopic methods. Full article
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Open AccessArticle The Sponge-associated Bacterium Bacillus licheniformis SAB1: A Source of Antimicrobial Compounds
Mar. Drugs 2010, 8(4), 1203-1212; doi:10.3390/md8041203
Received: 21 February 2010 / Revised: 9 March 2010 / Accepted: 22 March 2010 / Published: 9 April 2010
Cited by 36 | PDF Full-text (180 KB) | HTML Full-text | XML Full-text
Abstract
Several bacterial cultures were isolated from sponge Halichondria sp., collected from the Gujarat coast of the Indo Pacific region. These bacterial cultures were fermented in the laboratory (100 mL) and the culture filtrate was assayed for antibiotic activity against 16 strains of clinical
[...] Read more.
Several bacterial cultures were isolated from sponge Halichondria sp., collected from the Gujarat coast of the Indo Pacific region. These bacterial cultures were fermented in the laboratory (100 mL) and the culture filtrate was assayed for antibiotic activity against 16 strains of clinical pathogens. Bacillus sp. (SAB1), the most potent of them and antagonistic to several clinically pathogenic Gram-positive, Gram-negative bacteria and the fungus Aspergillus fumigatus was chosen for further investigation. Analysis of the nucleotide sequence of the 16S rDNA gene of Bacillus sp. SAB1 showed a strong similarity (100%) with the 16S rDNA gene of Bacillus licheniformis HNL09. The bioactive compounds produced by Bacillus licheniformis SAB1 (GenBank accession number: DQ071568) were identified as indole (1), 3-phenylpropionic acid (2) and a dimer 4,4′-oxybis[3-phenylpropionic acid] (3) on the basis of their Fourier Transform Infrared (FTIR), Nuclear Magnetic Resonance (NMR) and Electrospray Ionization Mass Spectrometer (ESI-MS) data. There is a single reference on the natural occurrence of compound 3 from the leaves of a terrestrial herb Aptenia cordifolia in the literature, so to the best of our knowledge, this is a first report of its natural occurrence from a marine source. The recovery of bacterial strains with antimicrobial activity suggests that marine-invertebrates remain a rich source for the isolation of culturable isolates capable of producing novel bioactive secondary metabolites. Full article
Open AccessArticle Investigation of Pectenotoxin Profiles in the Yellow Sea (China) Using a Passive Sampling Technique
Mar. Drugs 2010, 8(4), 1263-1272; doi:10.3390/md8041263
Received: 21 February 2010 / Revised: 16 March 2010 / Accepted: 7 April 2010 / Published: 15 April 2010
Cited by 12 | PDF Full-text (309 KB) | HTML Full-text | XML Full-text
Abstract
Pectenotoxins (PTXs) are a group of lipophilic algal toxins. These toxins have been found in algae and shellfish from Japan, New Zealand, Ireland, Norway and Portugal. PTX profiles vary with geographic location of collection site. The aim of the present study was to
[...] Read more.
Pectenotoxins (PTXs) are a group of lipophilic algal toxins. These toxins have been found in algae and shellfish from Japan, New Zealand, Ireland, Norway and Portugal. PTX profiles vary with geographic location of collection site. The aim of the present study was to investigate PTX profiles from the Yellow Sea, China. The sampling location was within an aquatic farm (N36°12.428´, E120°17.826´) near the coast of Qingdao, China, in the Yellow Sea from 28July to 29August 2006. PTXs in seawater were determined using a solid phase adsorption toxin tracking (SPATT) method. PTXs were analyzed by HPLC-MSMS. PTX-2, PTX-2 sec acid (PTX-2 SA) and 7-epi-PTX-2 SA were found in seawater samples. The highest levels of PTXs (107 ng/g of resin PTX-2, 50 ng/g of resin PTX-2 SA plus 7-epi-PTX-2 SA) in seawater were found on 1 August, 2006. From 1 August to 29 August, the levels of PTX-2 and PTX-2 SA decreased. In the same area, the marine algae, Dinophysis acuminata was found in the seawater in the summer months of 2006. This indicated that Dinophysis acuumuta might be the original source of PTXs. PTX-11 and PTX-12a/b were not found in seawater. Full article
(This article belongs to the Special Issue Algal Toxins)
Open AccessArticle Distribution and Abundance of MAAs in 33 Species of Microalgae across 13 Classes
Mar. Drugs 2010, 8(4), 1273-1291; doi:10.3390/md8041273
Received: 8 March 2010 / Revised: 9 April 2010 / Accepted: 13 April 2010 / Published: 16 April 2010
Cited by 43 | PDF Full-text (217 KB) | HTML Full-text | XML Full-text
Abstract
We provide a direct comparison of the distribution and abundance of mycosporine-like amino acids (MAAs) in a diverse range of microalgal cultures (33 species across 13 classes) grown without supplementary ultraviolet radiation (UV). We compare the MAAs in cultures with those present in
[...] Read more.
We provide a direct comparison of the distribution and abundance of mycosporine-like amino acids (MAAs) in a diverse range of microalgal cultures (33 species across 13 classes) grown without supplementary ultraviolet radiation (UV). We compare the MAAs in cultures with those present in characterised natural phytoplankton populations from the English Channel. We detected 25 UV absorbing compounds including at least two with multiple absorption maxima. We used LC-MS to provide chemical characterisation of the six most commonly occurring MAAs, namely, palythene, palythine, mycosporine-glycine, palythenic acid, porphyra-334 and shinorine. MAAs were abundant (up to 7 pg MAA cell−1)in 10 species, with more minor and often unknown MAAs in a further 11 cultures. Shinorine was the most frequently occurring and abundant MAA (up to 6.5 pg cell−1) and was present in all but two of the MAA-containing species. The study provides further insight into the diversity and abundance of MAAs important from an ecological perspective and as potential source of natural alternatives to synthetic sunscreens. Full article
(This article belongs to the Special Issue Marine Photoprotective Compounds)
Open AccessArticle The Tropical Brown Alga Lobophora variegata: A Source of Antiprotozoal Compounds
Mar. Drugs 2010, 8(4), 1292-1304; doi:10.3390/md8041292
Received: 2 March 2010 / Revised: 29 March 2010 / Accepted: 2 April 2010 / Published: 16 April 2010
Cited by 25 | PDF Full-text (152 KB) | HTML Full-text | XML Full-text
Abstract
Lobophora variegata, a brown alga collected from the coast of the Yucatan peninsula, Mexico, was studied for antiprotozoal activity against Giardia intestinalis, Entamoeba histolytica and Trichomonas vaginalis. The whole extract showed the highest activity against T. vaginalis, with an
[...] Read more.
Lobophora variegata, a brown alga collected from the coast of the Yucatan peninsula, Mexico, was studied for antiprotozoal activity against Giardia intestinalis, Entamoeba histolytica and Trichomonas vaginalis. The whole extract showed the highest activity against T. vaginalis, with an IC50 value of 3.2 mg/mL. For the fractions, the best antiprotozoal activity was found in non-polar fractions. The chloroform fraction of the extract contained a major sulfoquinovosyldiacylglycerol (SQDG), identified as 1-O-palmitoyl-2-O-myristoyl-3-O-(6´´´-sulfo-a-D-quinovopyranosyl)-glycerol (1), together with small amounts of 1,2-di-O-palmitoyl-3-O-(6´´´-sulfo-a-D-quinovopyranosyl)-glycerol (2) and a new compound identified as 1-O-palmitoyl-2-O-oleoyl-3-O-(6´´´-sulfo-a-D-quinovopyranosyl)-glycerol (3). Their structures were elucidated on the basis of chemical and enzymatic hydrolysis and careful analysis of FAB-MS and NMR spectroscopic data. This is the first report on the isolation of SQDGs from L. variegata. The mixture of 13 showed good activity against E. histolytica and moderate activity against T. vaginalis with IC50s of 3.9 and 8.0 mg/mL, respectively, however, the activity of 13 is not as effective as metronidazole. These results afford ground information for the potential use of the whole extract and fractions of this species in protozoal infections. Full article
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Open AccessArticle Anthracenedione Derivatives as Anticancer Agents Isolated from Secondary Metabolites of the Mangrove Endophytic Fungi
Mar. Drugs 2010, 8(4), 1469-1481; doi:10.3390/md8041469
Received: 12 March 2010 / Revised: 1 April 2010 / Accepted: 21 April 2010 / Published: 23 April 2010
Cited by 39 | PDF Full-text (525 KB) | HTML Full-text | XML Full-text
Abstract
In this article, we report anticancer activity of 14 anthracenedione derivatives separated from the secondary metabolites of the mangrove endophytic fungi Halorosellinia sp. (No. 1403) and Guignardia sp. (No. 4382). Some of them inhibited potently the growth of KB and KBv200 cells, among
[...] Read more.
In this article, we report anticancer activity of 14 anthracenedione derivatives separated from the secondary metabolites of the mangrove endophytic fungi Halorosellinia sp. (No. 1403) and Guignardia sp. (No. 4382). Some of them inhibited potently the growth of KB and KBv200 cells, among which compound 6 displayed strong cytotoxicity with IC50 values of 3.17 and 3.21 μM to KB and KBv200 cells, respectively. Furthermore, we demonstrate that the mechanism involved in the apoptosis induced by compound 6 is probably related to mitochondrial dysfunction. Additionally, the structure-activity relationships of these compounds are discussed. Full article

Review

Jump to: Research

Open AccessReview Generating a Generation of Proteasome Inhibitors: From Microbial Fermentation to Total Synthesis of Salinosporamide A (Marizomib) and Other Salinosporamides
Mar. Drugs 2010, 8(4), 835-880; doi:10.3390/md8040835
Received: 28 February 2010 / Revised: 19 March 2010 / Accepted: 22 March 2010 / Published: 25 March 2010
Cited by 31 | PDF Full-text (377 KB) | HTML Full-text | XML Full-text
Abstract
The salinosporamides are potent proteasome inhibitors among which the parent marine-derived natural product salinosporamide A (marizomib; NPI-0052; 1) is currently in clinical trials for the treatment of various cancers. Methods to generate this class of compounds include fermentation and natural products chemistry,
[...] Read more.
The salinosporamides are potent proteasome inhibitors among which the parent marine-derived natural product salinosporamide A (marizomib; NPI-0052; 1) is currently in clinical trials for the treatment of various cancers. Methods to generate this class of compounds include fermentation and natural products chemistry, precursor-directed biosynthesis, mutasynthesis, semi-synthesis, and total synthesis. The end products range from biochemical tools for probing mechanism of action to clinical trials materials; in turn, the considerable efforts to produce the target molecules have expanded the technologies used to generate them. Here, the full complement of methods is reviewed, reflecting remarkable contributions from scientists of various disciplines over a period of 7 years since the first publication of the structure of 1. Full article
(This article belongs to the Special Issue Synthesis around Marine Natural Products)
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Open AccessReview Impact of Marine Drugs on Cytoskeleton-Mediated Reproductive Events
Mar. Drugs 2010, 8(4), 881-915; doi:10.3390/md8040881
Received: 16 February 2010 / Revised: 2 March 2010 / Accepted: 23 March 2010 / Published: 25 March 2010
Cited by 10 | PDF Full-text (254 KB) | HTML Full-text | XML Full-text
Abstract
Marine organisms represent an important source of novel bioactive compounds, often showing unique modes of action. Such drugs may be useful tools to study complex processes such as reproduction; which is characterized by many crucial steps that start at gamete maturation and activation
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Marine organisms represent an important source of novel bioactive compounds, often showing unique modes of action. Such drugs may be useful tools to study complex processes such as reproduction; which is characterized by many crucial steps that start at gamete maturation and activation and virtually end at the first developmental stages. During these processes cytoskeletal elements such as microfilaments and microtubules play a key-role. In this review we describe: (i) the involvement of such structures in both cellular and in vitro processes; (ii) the toxins that target the cytoskeletal elements and dynamics; (iii) the main steps of reproduction and the marine drugs that interfere with these cytoskeleton-mediated processes. We show that marine drugs, acting on microfilaments and microtubules, exert a wide range of impacts on reproductive events including sperm maturation and motility, oocyte maturation, fertilization, and early embryo development. Full article
(This article belongs to the Special Issue Marine Bioactive Compounds Acting on Animal Reproduction)
Open AccessReview Chitosan in Plant Protection
Mar. Drugs 2010, 8(4), 968-987; doi:10.3390/md8040968
Received: 12 March 2010 / Revised: 24 March 2010 / Accepted: 29 March 2010 / Published: 30 March 2010
Cited by 114 | PDF Full-text (134 KB) | HTML Full-text | XML Full-text
Abstract
Chitin and chitosan are naturally-occurring compounds that have potential in agriculture with regard to controlling plant diseases. These molecules were shown to display toxicity and inhibit fungal growth and development. They were reported to be active against viruses, bacteria and other pests. Fragments
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Chitin and chitosan are naturally-occurring compounds that have potential in agriculture with regard to controlling plant diseases. These molecules were shown to display toxicity and inhibit fungal growth and development. They were reported to be active against viruses, bacteria and other pests. Fragments from chitin and chitosan are known to have eliciting activities leading to a variety of defense responses in host plants in response to microbial infections, including the accumulation of phytoalexins, pathogen-related (PR) proteins and proteinase inhibitors, lignin synthesis, and callose formation. Based on these and other proprieties that help strengthen host plant defenses, interest has been growing in using them in agricultural systems to reduce the negative impact of diseases on yield and quality of crops. This review recapitulates the properties and uses of chitin, chitosan, and their derivatives, and will focus on their applications and mechanisms of action during plant-pathogen interactions. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
Open AccessReview The Halogenated Metabolism of Brown Algae (Phaeophyta), Its Biological Importance and Its Environmental Significance
Mar. Drugs 2010, 8(4), 988-1010; doi:10.3390/md8040988
Received: 25 February 2010 / Revised: 13 March 2010 / Accepted: 25 March 2010 / Published: 30 March 2010
Cited by 60 | PDF Full-text (655 KB) | HTML Full-text | XML Full-text
Abstract
Brown algae represent a major component of littoral and sublittoral zones in temperate and subtropical ecosystems. An essential adaptive feature of this independent eukaryotic lineage is the ability to couple oxidative reactions resulting from exposure to sunlight and air with the halogenations of
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Brown algae represent a major component of littoral and sublittoral zones in temperate and subtropical ecosystems. An essential adaptive feature of this independent eukaryotic lineage is the ability to couple oxidative reactions resulting from exposure to sunlight and air with the halogenations of various substrates, thereby addressing various biotic and abiotic stresses i.e., defense against predators, tissue repair, holdfast adhesion, and protection against reactive species generated by oxidative processes. Whereas marine organisms mainly make use of bromine to increase the biological activity of secondary metabolites, some orders of brown algae such as Laminariales have also developed a striking capability to accumulate and to use iodine in physiological adaptations to stress. We review selected aspects of the halogenated metabolism of macrophytic brown algae in the light of the most recent results, which point toward novel functions for iodide accumulation in kelps and the importance of bromination in cell wall modifications and adhesion properties of brown algal propagules. The importance of halogen speciation processes ranges from microbiology to biogeochemistry, through enzymology, cellular biology and ecotoxicology. Full article
(This article belongs to the Special Issue Bioactive Halogenated Metabolites of Marine Origin)
Open AccessReview Biosynthesis and Molecular Genetics of Polyketides in Marine Dinoflagellates
Mar. Drugs 2010, 8(4), 1011-1048; doi:10.3390/md8041011
Received: 24 February 2010 / Revised: 17 March 2010 / Accepted: 26 March 2010 / Published: 31 March 2010
Cited by 44 | PDF Full-text (423 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Marine dinoflagellates are the single most important group of algae that produce toxins, which have a global impact on human activities. The toxins are chemically diverse, and include macrolides, cyclic polyethers, spirolides and purine alkaloids. Whereas there is a multitude of studies describing
[...] Read more.
Marine dinoflagellates are the single most important group of algae that produce toxins, which have a global impact on human activities. The toxins are chemically diverse, and include macrolides, cyclic polyethers, spirolides and purine alkaloids. Whereas there is a multitude of studies describing the pharmacology of these toxins, there is limited or no knowledge regarding the biochemistry and molecular genetics involved in their biosynthesis. Recently, however, exciting advances have been made. Expressed sequence tag sequencing studies have revealed important insights into the transcriptomes of dinoflagellates, whereas other studies have implicated polyketide synthase genes in the biosynthesis of cyclic polyether toxins, and the molecular genetic basis for the biosynthesis of paralytic shellfish toxins has been elucidated in cyanobacteria. This review summarises the recent progress that has been made regarding the unusual genomes of dinoflagellates, the biosynthesis and molecular genetics of dinoflagellate toxins. In addition, the evolution of these metabolic pathways will be discussed, and an outlook for future research and possible applications is provided. Full article
(This article belongs to the Special Issue Marine Dinoflagellates)
Open AccessReview Microtubule-Stabilizing Drugs from Marine Sponges: Focus on Peloruside A and Zampanolide
Mar. Drugs 2010, 8(4), 1059-1079; doi:10.3390/md8041059
Received: 1 March 2010 / Revised: 13 March 2010 / Accepted: 29 March 2010 / Published: 31 March 2010
Cited by 38 | PDF Full-text (405 KB) | HTML Full-text | XML Full-text
Abstract
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
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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. Full article
(This article belongs to the Special Issue Bioactive Compounds from Marine Sponges)
Open AccessReview Angiotensin-I-Converting Enzyme (ACE) Inhibitors from Marine Resources: Prospects in the Pharmaceutical Industry
Mar. Drugs 2010, 8(4), 1080-1093; doi:10.3390/md8041080
Received: 19 February 2010 / Accepted: 29 March 2010 / Published: 31 March 2010
Cited by 105 | PDF Full-text (143 KB) | HTML Full-text | XML Full-text
Abstract
Hypertension or high blood pressure is one of the major independent risk factors for cardiovascular diseases. Angiotensin-I-converting enzyme (EC 3.4.15.1; ACE) plays an important physiological role in regulation of blood pressure by converting angiotensin I to angiotensin II, a potent vasoconstrictor. Therefore, the
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Hypertension or high blood pressure is one of the major independent risk factors for cardiovascular diseases. Angiotensin-I-converting enzyme (EC 3.4.15.1; ACE) plays an important physiological role in regulation of blood pressure by converting angiotensin I to angiotensin II, a potent vasoconstrictor. Therefore, the inhibition of ACE activity is a major target in the prevention of hypertension. Recently, the search for natural ACE inhibitors as alternatives to synthetic drugs is of great interest to prevent several side effects and a number of novel compounds such as bioactive peptides, chitooligosaccharide derivatives (COS) and phlorotannins have been derived from marine organisms as potential ACE inhibitors. These inhibitory derivatives can be developed as nutraceuticals and pharmaceuticals with potential to prevent hypertension. Hence, the aim of this review is to discuss the marine-derived ACE inhibitors and their future prospects as novel therapeutic drug candidates for treat hypertension. Full article
Open AccessReview Mediterranean Jellyfish Venoms: A Review on Scyphomedusae
Mar. Drugs 2010, 8(4), 1122-1152; doi:10.3390/md8041122
Received: 10 February 2010 / Revised: 15 March 2010 / Accepted: 30 March 2010 / Published: 4 April 2010
Cited by 55 | PDF Full-text (381 KB) | HTML Full-text | XML Full-text
Abstract
The production of natural toxins is an interesting aspect, which characterizes the physiology and the ecology of a number of marine species that use them for defence/offence purposes. Cnidarians are of particular concern from this point of view; their venoms are contained in
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The production of natural toxins is an interesting aspect, which characterizes the physiology and the ecology of a number of marine species that use them for defence/offence purposes. Cnidarians are of particular concern from this point of view; their venoms are contained in specialized structures–the nematocysts–which, after mechanical or chemical stimulation, inject the venom in the prey or in the attacker. Cnidarian stinging is a serious health problem for humans in the zones where extremely venomous jellyfish or anemones are common, such as in temperate and tropical oceanic waters and particularly along several Pacific coasts, and severe cases of envenomation, including also lethal cases mainly induced by cubomedusae, were reported. On the contrary, in the Mediterranean region the problem of jellyfish stings is quite modest, even though they can have anyhow an impact on public health and be of importance from the ecological and economic point of view owing to the implications on ecosystems and on some human activities such as tourism, bathing and fishing. This paper reviews the knowledge about the various aspects related to the occurrence and the stinging of the Mediterranean scyphozoan jellyfish as well as the activity of their venoms. Full article
(This article belongs to the Special Issue Marine Biotoxins: Novel Issues about Old Compounds)
Open AccessReview Bacteriocin as Weapons in the Marine Animal-Associated Bacteria Warfare: Inventory and Potential Applications as an Aquaculture Probiotic
Mar. Drugs 2010, 8(4), 1153-1177; doi:10.3390/md8041153
Received: 6 February 2010 / Revised: 28 March 2010 / Accepted: 1 April 2010 / Published: 4 April 2010
Cited by 47 | PDF Full-text (954 KB) | HTML Full-text | XML Full-text
Abstract
As the association of marine animals with bacteria has become more commonly recognized, researchers have increasingly questioned whether these animals actually produce many of the bioactive compounds originally isolated from them. Bacteriocins, ribosomally synthesized antibiotic peptides, constitute one of the most potent weapons
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As the association of marine animals with bacteria has become more commonly recognized, researchers have increasingly questioned whether these animals actually produce many of the bioactive compounds originally isolated from them. Bacteriocins, ribosomally synthesized antibiotic peptides, constitute one of the most potent weapons to fight against pathogen infections. Indeed, bacteriocinogenic bacteria may prevent pathogen dissemination by occupying the same ecological niche. Bacteriocinogenic strains associated with marine animals are a relevant source for isolation of probiotics. This review draws up an inventory of the marine bacteriocinogenic strains isolated from animal-associated microbial communities, known to date. Bacteriocin-like inhibitory substances (BLIS) and fully-characterized bacteriocins are described. Finally, their applications as probiotics in aquaculture are discussed. Full article
(This article belongs to the Special Issue Bioactive Compounds from Marine Microbes)
Open AccessReview Anti-photoaging and Photoprotective Compounds Derived from Marine Organisms
Mar. Drugs 2010, 8(4), 1189-1202; doi:10.3390/md8041189
Received: 22 February 2010 / Revised: 30 March 2010 / Accepted: 7 April 2010 / Published: 8 April 2010
Cited by 55 | PDF Full-text (244 KB) | HTML Full-text | XML Full-text
Abstract
Marine organisms form a prominent component of the oceanic population, which significantly contribute in the production of cosmeceutical and pharmaceutical molecules with biologically efficient moieties. In addition to the molecules of various biological activities like anti-bacterial, anti-cancerous, anti-inflammatory and anti-oxidative etc., these organisms
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Marine organisms form a prominent component of the oceanic population, which significantly contribute in the production of cosmeceutical and pharmaceutical molecules with biologically efficient moieties. In addition to the molecules of various biological activities like anti-bacterial, anti-cancerous, anti-inflammatory and anti-oxidative etc., these organisms also produce potential photoprotective or anti-photoaging agents, which are attracting present day researchers. Continuous exposure to UV irradiation (both UV-A and UV-B) leads to the skin cancer and other photoaging complications, which are typically mediated by the reactive oxygen species (ROS), generated in the oxidative pathways. Many of the anti-oxidative and anti-photoaging compounds have been identified previously, which work efficiently against photodamage of the skin. Recently, marine originated photoprotective or anti-photoaging behavior was observed in the methanol extracts of Corallina pilulifera (CPM). These extracts were found to exert potent antioxidant activity and protective effect on UV-A-induced oxidative stress in human dermal fibroblast (HDF) cells by protecting DNA and also by inhibiting matrix metalloproteinases (MMPs), a key component in photoaging of the skin due to exposure to UV-A. The present review depicts various other photoprotective compounds from algae and other marine sources for further elaborative research and their probable use in cosmeceutical and pharmaceutical industries. Full article
(This article belongs to the Special Issue Marine Photoprotective Compounds)
Open AccessReview Conventional and Unconventional Antimicrobials from Fish, Marine Invertebrates and Micro-algae
Mar. Drugs 2010, 8(4), 1213-1262; doi:10.3390/md8041213
Received: 8 February 2010 / Revised: 2 April 2010 / Accepted: 12 April 2010 / Published: 14 April 2010
Cited by 74 | PDF Full-text (531 KB) | HTML Full-text | XML Full-text
Abstract
All eukaryotic organisms, single-celled or multi-cellular, produce a diverse array of natural anti-infective agents that, in addition to conventional antimicrobial peptides, also include proteins and other molecules often not regarded as part of the innate defences. Examples range from histones, fatty acids, and
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All eukaryotic organisms, single-celled or multi-cellular, produce a diverse array of natural anti-infective agents that, in addition to conventional antimicrobial peptides, also include proteins and other molecules often not regarded as part of the innate defences. Examples range from histones, fatty acids, and other structural components of cells to pigments and regulatory proteins. These probably represent very ancient defence factors that have been re-used in new ways during evolution. This review discusses the nature, biological role in host protection and potential biotechnological uses of some of these compounds, focusing on those from fish, marine invertebrates and marine micro-algae. Full article
(This article belongs to the Special Issue Marine Anti-infective Agents)
Open AccessReview Chitosan Based Polyelectrolyte Complexes as Potential Carrier Materials in Drug Delivery Systems
Mar. Drugs 2010, 8(4), 1305-1322; doi:10.3390/md8041305
Received: 9 February 2010 / Revised: 17 March 2010 / Accepted: 22 March 2010 / Published: 19 April 2010
Cited by 171 | PDF Full-text (385 KB) | HTML Full-text | XML Full-text
Abstract
Chitosan has been the subject of interest for its use as a polymeric drug carrier material in dosage form design due to its appealing properties such as biocompatibility, biodegradability, low toxicity and relatively low production cost from abundant natural sources. However, one drawback
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Chitosan has been the subject of interest for its use as a polymeric drug carrier material in dosage form design due to its appealing properties such as biocompatibility, biodegradability, low toxicity and relatively low production cost from abundant natural sources. However, one drawback of using this natural polysaccharide in modified release dosage forms for oral administration is its fast dissolution rate in the stomach. Since chitosan is positively charged at low pH values (below its pKa value), it spontaneously associates with negatively charged polyions in solution to form polyelectrolyte complexes. These chitosan based polyelectrolyte complexes exhibit favourable physicochemical properties with preservation of chitosan’s biocompatible characteristics. These complexes are therefore good candidate excipient materials for the design of different types of dosage forms. It is the aim of this review to describe complexation of chitosan with selected natural and synthetic polyanions and to indicate some of the factors that influence the formation and stability of these polyelectrolyte complexes. Furthermore, recent investigations into the use of these complexes as excipients in drug delivery systems such as nano- and microparticles, beads, fibers, sponges and matrix type tablets are briefly described. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
Open AccessReview Bioprocessing Data for the Production of Marine Enzymes
Mar. Drugs 2010, 8(4), 1323-1372; doi:10.3390/md8041323
Received: 5 March 2010 / Revised: 31 March 2010 / Accepted: 12 April 2010 / Published: 19 April 2010
Cited by 24 | PDF Full-text (373 KB) | HTML Full-text | XML Full-text
Abstract
This review is a synopsis of different bioprocess engineering approaches adopted for the production of marine enzymes. Three major modes of operation: batch, fed-batch and continuous have been used for production of enzymes (such as protease, chitinase, agarase, peroxidase) mainly from marine bacteria
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This review is a synopsis of different bioprocess engineering approaches adopted for the production of marine enzymes. Three major modes of operation: batch, fed-batch and continuous have been used for production of enzymes (such as protease, chitinase, agarase, peroxidase) mainly from marine bacteria and fungi on a laboratory bioreactor and pilot plant scales. Submerged, immobilized and solid-state processes in batch mode were widely employed. The fed-batch process was also applied in several bioprocesses. Continuous processes with suspended cells as well as with immobilized cells have been used. Investigations in shake flasks were conducted with the prospect of large-scale processing in reactors. Full article
(This article belongs to the Special Issue Enzymes from the Sea: Sources, Molecular Biology and Bioprocesses)
Open AccessReview The Outer Vestibule of the Na+ Channel–Toxin Receptor and Modulator of Permeation as Well as Gating
Mar. Drugs 2010, 8(4), 1373-1393; doi:10.3390/md8041373
Received: 3 February 2010 / Revised: 31 March 2010 / Accepted: 19 April 2010 / Published: 21 April 2010
Cited by 4 | PDF Full-text (324 KB) | HTML Full-text | XML Full-text
Abstract
The outer vestibule of voltage-gated Na+ channels is formed by extracellular loops connecting the S5 and S6 segments of all four domains (“P-loops”), which fold back into the membrane. Classically, this structure has been implicated in the control of ion permeation and
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The outer vestibule of voltage-gated Na+ channels is formed by extracellular loops connecting the S5 and S6 segments of all four domains (“P-loops”), which fold back into the membrane. Classically, this structure has been implicated in the control of ion permeation and in toxin blockage. However, conformational changes of the outer vestibule may also result in alterations in gating, as suggested by several P-loop mutations that gave rise to gating changes. Moreover, partial pore block by mutated toxins may reverse gating changes induced by mutations. Therefore, toxins that bind to the outer vestibule can be used to modulate channel gating. Full article
(This article belongs to the Special Issue Tetrodotoxin)
Open AccessReview Synthesis of the Marine Pyrroloiminoquinone Alkaloids, Discorhabdins
Mar. Drugs 2010, 8(4), 1394-1416; doi:10.3390/md8041394
Received: 7 April 2010 / Revised: 16 April 2010 / Accepted: 19 April 2010 / Published: 21 April 2010
Cited by 9 | PDF Full-text (346 KB) | HTML Full-text | XML Full-text
Abstract
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
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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. Full article
(This article belongs to the Special Issue Bioactive Compounds from Marine Sponges)
Open AccessReview Marine Drugs from Sponge-Microbe Association—A Review
Mar. Drugs 2010, 8(4), 1417-1468; doi:10.3390/md8041417
Received: 24 February 2010 / Revised: 13 April 2010 / Accepted: 19 April 2010 / Published: 22 April 2010
Cited by 156 | PDF Full-text (398 KB) | HTML Full-text | XML Full-text
Abstract
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
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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. Full article
(This article belongs to the Special Issue Bioactive Compounds from Marine Sponges)

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