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Mar. Drugs, Volume 6, Issue 4 (December 2008), Pages 514-659

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Research

Open AccessArticle Anticancer Alkaloid Lamellarins Inhibit Protein Kinases
Mar. Drugs 2008, 6(4), 514-527; doi:10.3390/md20080026
Received: 2 August 2008 / Revised: 18 September 2008 / Accepted: 26 September 2008 / Published: 8 October 2008
Cited by 58 | PDF Full-text (627 KB) | HTML Full-text | XML Full-text
Abstract
Lamellarins, a family of hexacyclic pyrrole alkaloids originally isolated from marine invertebrates, display promising anti-tumor activity. They induce apoptotic cell death through multi-target mechanisms, including inhibition of topoisomerase I, interaction with DNA and direct effects on mitochondria. We here report that lamellarins inhibit
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Lamellarins, a family of hexacyclic pyrrole alkaloids originally isolated from marine invertebrates, display promising anti-tumor activity. They induce apoptotic cell death through multi-target mechanisms, including inhibition of topoisomerase I, interaction with DNA and direct effects on mitochondria. We here report that lamellarins inhibit several protein kinases relevant to cancer such as cyclin-dependent kinases, dualspecificity tyrosine phosphorylation activated kinase 1A, casein kinase 1, glycogen synthase kinase-3 and PIM-1. A good correlation is observed between the effects of lamellarins on protein kinases and their action on cell death, suggesting that inhibition of specific kinases may contribute to the cytotoxicity of lamellarins. Structure/activity relationship suggests several paths for the optimization of lamellarins as kinase inhibitors. Full article
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Open AccessArticle Characterizing the Anti-HIV Activity of Papuamide A
Mar. Drugs 2008, 6(4), 528-549; doi:10.3390/md20080027
Received: 22 July 2008 / Revised: 8 September 2008 / Accepted: 2 October 2008 / Published: 8 October 2008
Cited by 26 | PDF Full-text (540 KB) | HTML Full-text | XML Full-text
Abstract
Papuamide A is representative of a class of marine derived cyclic depsipeptides, reported to have cytoprotective activity against HIV-1 in vitro. We show here that papuamide A acts as an entry inhibitor, preventing human immunodeficiency virus infection of host cells and that
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Papuamide A is representative of a class of marine derived cyclic depsipeptides, reported to have cytoprotective activity against HIV-1 in vitro. We show here that papuamide A acts as an entry inhibitor, preventing human immunodeficiency virus infection of host cells and that this inhibition is not specific to R5 or X4 tropic virus. This inhibition of viral entry was determined to not be due to papuamide A binding to CD4 or HIV gp120, the two proteins involved in the cell-virus recognition and binding. Furthermore, papuamide A was able to inhibit HIV pseudotype viruses expressing envelope glycoproteins from vesicular stomatitis virus or amphotropic murine leukemia virus indicating the mechanism of viral entry inhibition is not HIV-1 envelope glycoprotein specific. Time delayed addition studies with the pseudotyped viruses show that papuamide A inhibits viral infection only at the initial stage of the viral life cycle. Additionally, pretreatment studies revealed that the virus, and not the cell, is the target of papuamide A’s action. Together, these results suggest a direct virucidal mechanism of HIV-1 inhibition by papuamide A. We also demonstrate here that the other papuamides (B-D) are able to inhibit viral entry indicating that the free amino moiety of 2,3-diaminobutanoic acid residue is not required for the virucidal activity. Full article
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Open AccessArticle A Tropical Marine Microbial Natural Products Geobibliography as an Example of Desktop Exploration of Current Research Using Web Visualisation Tools
Mar. Drugs 2008, 6(4), 550-577; doi:10.3390/md20080028
Received: 30 June 2008 / Revised: 9 October 2008 / Accepted: 9 October 2008 / Published: 13 October 2008
Cited by 2 | PDF Full-text (9628 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Microbial marine biodiscovery is a recent scientific endeavour developing at a time when information and other technologies are also undergoing great technical strides. Global visualisation of datasets is now becoming available to the world through powerful and readily available software such as Worldwind
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Microbial marine biodiscovery is a recent scientific endeavour developing at a time when information and other technologies are also undergoing great technical strides. Global visualisation of datasets is now becoming available to the world through powerful and readily available software such as Worldwind ™, ArcGIS Explorer ™ and Google Earth ™. Overlaying custom information upon these tools is within the hands of every scientist and more and more scientific organisations are making data available that can also be integrated into these global visualisation tools. The integrated global view that these tools enable provides a powerful desktop exploration tool. Here we demonstrate the value of this approach to marine microbial biodiscovery by developing a geobibliography that incorporates citations on tropical and near-tropical marine microbial natural products research with Google Earth ™ and additional ancillary global data sets. The tools and software used are all readily available and the reader is able to use and install the material described in this article. Full article
(This article belongs to the Special Issue Bioactive Compounds from Marine Microorganisms)
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Open AccessArticle Acetylcholinesterase-Inhibiting Activity of Pyrrole Derivatives from a Novel Marine Gliding Bacterium, Rapidithrix thailandica
Mar. Drugs 2008, 6(4), 578-586; doi:10.3390/md6040578
Received: 2 September 2008 / Revised: 3 October 2008 / Accepted: 8 October 2008 / Published: 13 October 2008
Cited by 37 | PDF Full-text (198 KB) | HTML Full-text | XML Full-text
Abstract
Acetylcholinesterase-inhibiting activity of marinoquinoline A (1), a new pyrroloquinoline from a novel species of a marine gliding bacterium Rapidithrix thailandica, was assessed (IC50 4.9 μM). Two related pyrrole derivatives, 3-(2'-aminophenyl)-pyrrole (3) and 2,2-dimethyl-pyrrolo-1,2-dihydroquinoline (4), were also isolated from two other
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Acetylcholinesterase-inhibiting activity of marinoquinoline A (1), a new pyrroloquinoline from a novel species of a marine gliding bacterium Rapidithrix thailandica, was assessed (IC50 4.9 μM). Two related pyrrole derivatives, 3-(2'-aminophenyl)-pyrrole (3) and 2,2-dimethyl-pyrrolo-1,2-dihydroquinoline (4), were also isolated from two other strains of R. thailandica. The isolation of 3 from a natural source is reported here for the first time. Compound 4 was proposed to be an isolation artifact derived from 3. The two isolated compounds were virtually inactive in the acetylcholinesterase-inhibitory assay (enzyme inhibition < 30% at 0.1 g L-1). Full article
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Open AccessArticle Detection of Diarrheic Shellfish Poisoning and Azaspiracids Toxins in Moroccan Mussels: Comparison of LC-MS Method with the Commercial Immunoassay Kit
Mar. Drugs 2008, 6(4), 587-594; doi:10.3390/md6040587
Received: 18 January 2008 / Revised: 15 September 2008 / Accepted: 8 October 2008 / Published: 27 October 2008
Cited by 21 | PDF Full-text (55 KB) | HTML Full-text | XML Full-text
Abstract
Diarrheic shellfish poisoning (DSP) is one of recurrent gastrointestinal illnesses in Morocco, resulting from consumption of contaminated shellfish. In order to develop a rapid and reliable technique for toxins detection, we have compared the results obtained by a commercial immunoassay-“DSP-Check” kit” with those
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Diarrheic shellfish poisoning (DSP) is one of recurrent gastrointestinal illnesses in Morocco, resulting from consumption of contaminated shellfish. In order to develop a rapid and reliable technique for toxins detection, we have compared the results obtained by a commercial immunoassay-“DSP-Check” kit” with those obtained by LC-MS. Both techniques are capable of detecting the toxins in the whole flesh extract which was subjected to prior alkaline hydrolysis in order to detect simultaneously the esterified and non esterified toxin forms. The LC-MS method was found to be able to detect a high level of okadaic acid (OA), low level of dinophysistoxin-2 (DTX2), and surprisingly traces of azaspiracids 2 (AZA2) in mussels. This is the first report of a survey carried out for azaspiracids (AZP) contamination of shellfish harvested in the coastal areas of Morocco. The “DSP-Check” kit was found to detect quantitatively DSP toxins in all contaminated samples containing only OA provided that the parent toxins were within the range of detection and was not in an ester form. A good correlation was observed between the two methods when appropriate dilutions were performed. The immunoassay kit appeared to be more sensitive, specific and faster than LC-MS for determination of DSP in total shellfish extract. Full article
Open AccessArticle Extracts from Cladiella australis, Clavularia viridis and Klyxum simplex (Soft Corals) are Capable of Inhibiting the Growth of Human Oral Squamous Cell Carcinoma Cells
Mar. Drugs 2008, 6(4), 595-606; doi:10.3390/md6040595
Received: 4 July 2008 / Revised: 13 October 2008 / Accepted: 29 October 2008 / Published: 3 November 2008
Cited by 9 | PDF Full-text (1245 KB) | HTML Full-text | XML Full-text
Abstract
Many biomedical products have already been obtained from marine organisms. In order to search more therapeutic drugs against cancer, this study demonstrates the cytotoxicity effects of Cladiella australis, Clavularia viridis and Klyxum simplex extractson human oral squamous cell carcinoma (SCC4, SCC9 and
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Many biomedical products have already been obtained from marine organisms. In order to search more therapeutic drugs against cancer, this study demonstrates the cytotoxicity effects of Cladiella australis, Clavularia viridis and Klyxum simplex extractson human oral squamous cell carcinoma (SCC4, SCC9 and SCC25) cells using cell adhesion and cell viability assay. The morphological alterations in SCCs cells after treatment with three extracts, such as typical nuclear condensation, nuclear fragmentation and apoptotic bodies of cells were demonstrated by Hoechst stain. Flow cytometry indicated that three extracts sensitized SCC25 cells in the G0/G1 and S-G2/M phases with a concomitant significantly increased sub-G1 fraction, indicating cell death by apoptosis. This apoptosis process was accompanied by activation of caspase-3 expression after SCC25 cells were treated with three extracts. Thereby, it is possible that extracts of C. australis, C. viridis and K. simplex cause apoptosis of SCCs and warrant further research investigating the possible anti-oral cancer compounds in these soft corals. Full article
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Open AccessArticle Antioxidant Activities of Hydrolysates of Arca Subcrenata Prepared with Three Proteases
Mar. Drugs 2008, 6(4), 607-619; doi:10.3390/md6040607
Received: 13 September 2008 / Revised: 11 November 2008 / Accepted: 14 November 2008 / Published: 20 November 2008
Cited by 28 | PDF Full-text (311 KB) | HTML Full-text | XML Full-text
Abstract
In order to get products with antioxidant activity from Arca subcrenata Lischke, the optimal hydrolase and hydrolysis conditionswere investigated in the paper. Three proteases (neutrase, alcalase and papain) were applied to hydrolyze the homogenate of A. subcrenata. An orthogonaldesign was used to
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In order to get products with antioxidant activity from Arca subcrenata Lischke, the optimal hydrolase and hydrolysis conditionswere investigated in the paper. Three proteases (neutrase, alcalase and papain) were applied to hydrolyze the homogenate of A. subcrenata. An orthogonaldesign was used to optimize hydrolysis conditions, and the pH-stat methods was used to determine the degree of hydrolysis. Viewed from the angle ofreducing power, such as scavenging activities against α,α-diphenyl-β-picrylhydrazyl (DPPH) radical and hydrogen peroxide, the antioxidantactivities of the alcalase hydrolysate (AH) were superior to neutrase hydrolysate (NH) and papain hydrolysate (PH), and its EC50 values in DPPHradical and hydrogen peroxide scavenging effect were 6.23 mg/ml and 19.09 mg/ml, respectively. Moreover, compared with products hydrolyzed byneutrase and papain, the molecular mass of AH was lower and its content ofamino acid of peptides was higher. Therefore, alcalase was selected as theoptimal enzyme to produce active ingredients since its hydrolysate exhibitedthe best antioxidant activity among them and possessed large amount ofpotential active peptides. Full article
Open AccessArticle Characterization of Streptomyces spp. Isolated from the Sea Surface Microlayer in the Trondheim Fjord, Norway
Mar. Drugs 2008, 6(4), 620-635; doi:10.3390/md6040620
Received: 28 October 2008 / Revised: 25 November 2008 / Accepted: 27 November 2008 / Published: 1 December 2008
Cited by 26 | PDF Full-text (721 KB) | HTML Full-text | XML Full-text
Abstract
The water surface microlayer is still poorly explored, although it has been shown to contain a high density of metabolically active bacteria, often called bacterioneuston. Actinomycetes from the surface microlayer in the Trondheim fjord, Norway, have been isolated and characterized. A total of
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The water surface microlayer is still poorly explored, although it has been shown to contain a high density of metabolically active bacteria, often called bacterioneuston. Actinomycetes from the surface microlayer in the Trondheim fjord, Norway, have been isolated and characterized. A total of 217 isolates from two separate samples morphologically resembling the genus Streptomyces have been further investigated in this study. Antimicrobial assays showed that about 80% of the isolates exhibited antagonistic activity against nonfilamentous fungus, Gram-negative, and Gram-positive bacteria. Based on the macroscopic analyses and inhibition patterns from the antimicrobial assays, the sub-grouping of isolates was performed. Partial 16S rDNAs from the candidates from each subgroup were sequenced and phylogenetic analysis performed. 7 isolates with identical 16S rDNA sequences were further studied for the presence of PKS type I genes. Sequencing and phylogenetic analysis of the PKS gene fragments revealed that horizontal gene transfer between closely related species might have taken place. Identification of unique PKS genes in these isolates implies that dereplication can not be performed based solely on the 16S rDNA sequences. The results obtained in this study suggest that streptomycetes from the neuston population may be an interesting source for discovery of new antimicrobial agents. Full article
(This article belongs to the Special Issue Bioactive Compounds from Marine Microorganisms)
Open AccessArticle Immunomodulatory Effects of Domoic Acid Differ Between In vivo and In vitro Exposure in Mice
Mar. Drugs 2008, 6(4), 636-659; doi:10.3390/md6040636
Received: 27 October 2008 / Revised: 8 December 2008 / Accepted: 15 December 2008 / Published: 22 December 2008
Cited by 12 | PDF Full-text (1309 KB) | HTML Full-text | XML Full-text
Abstract
The immunotoxic potential of domoic acid (DA), a well-characterized neurotoxin, has not been fully investigated. Phagocytosis and lymphocyte proliferation were evaluated following in vitro and in vivo exposure to assay direct vs indirect effects. Mice were injected intraperitoneally with a single dose of
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The immunotoxic potential of domoic acid (DA), a well-characterized neurotoxin, has not been fully investigated. Phagocytosis and lymphocyte proliferation were evaluated following in vitro and in vivo exposure to assay direct vs indirect effects. Mice were injected intraperitoneally with a single dose of DA (2.5 µg/g b.w.) and sampled after 12, 24, or 48 hr. In a separate experiment, leukocytes and splenocytes were exposed in vitro to 0, 1, 10, or 100 µM DA. In vivo exposure resulted in a significant increase in monocyte phagocytosis (12-hr), a significant decrease in neutrophil phagocytosis (24-hr), a significant decrease in monocyte phagocytosis (48-hr), and a significant reduction in T-cell mitogen-induced lymphocyte proliferation (24-hr). In vitro exposure significantly reduced neutrophil and monocyte phagocytosis at 1 µM. B- and T-cell mitogen-induced lymphocyte proliferation were both significantly increased at 1 and 10 µM, and significantly decreased at 100 µM. Differences between in vitro and in vivo results suggest that DA may exert its immunotoxic effects both directly and indirectly. Modulation of cytosolic calcium suggests that DA exerts its effects through ionotropic glutamate subtype surface receptors at least on monocytes. This study is the first to identify DA as an immunotoxic chemical in a mammalian species. Full article

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