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William H. Gerwick - One of the best experts on this subject based on the ideXlab platform.
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Wewakamide A and guineamide G, cyclic depsipeptides from the marine cyanobacteria Lyngbya semiplena and Lyngbya majuscula.
Journal of Microbiology and Biotechnology, 2011Co-Authors: Bingnan Han, Harald Gross, Kerry L. Mcphail, Doug Goeger, Claudia S. Maier, William H. GerwickAbstract:Two new cyclic depsipeptides wewakamide A (1) and guineamide G (2) have been isolated from the marine cyanobacterium Lyngbya semiplena and Lyngbya majuscula, respectively, collected from Papua New Guinea. The amino and hydroxy acid partial structures of wewakamide A and guineamide G were elucidated through extensive spectroscopic techniques, including HR-FABMS, 1D (1)H and (13)C NMR, as well as 2D COSY, HSQC, HSQCTOCSY, and HMBC spectra. The sequence of the residues of wewakamide A was determined through a combination of ESI-MS/MS, HMBC, and ROESY. Wewakamide A possesses a β-amino acid, 3-amino-2-methylbutanoic acid (Maba) residue, which has only been previously identified in two natural products, guineamide B (3) and dolastatin D (4). Although both new compounds (1,2) showed potent brine shrimp toxicity, only guineamide G displayed significant cytotoxicity to a mouse neuroblastoma cell line with LC(50) values of 2.7 micrometer.
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the structure elucidation of isomalyngamide k from the marine cyanobacterium Lyngbya majuscula by experimental and dft computational methods
Journal of Molecular Structure, 2011Co-Authors: Bingnan Han, William H. Gerwick, Uwe M Reinscheid, Harald GrossAbstract:The 2Z-isomer of malyngamide K has been isolated along with the known compounds malyngamide C, deoxy-C and K, and characterized from a Papua New Guinea field collection of the cyanobacterium Lyngbya majuscula. The planar structure was deduced by 1D and 2D NMR spectroscopic and mass spectral data interpretation. The absolute configurations were determined on the basis of spectroscopic techniques, chemical degradation and DFT theoretical calculations.
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palmyramide a a cyclic depsipeptide from a palmyra atoll collection of the marine cyanobacterium Lyngbya majuscula
Journal of Natural Products, 2010Co-Authors: Masatoshi Taniguchi, Niclas Engene, Pieter C. Dorrestein, Joshawna K Nunnery, Eduardo Esquenazi, Tara Byrum, William H. GerwickAbstract:Bioassay-guided fractionation of the extract of a consortium of a marine cyanobacterium and a red alga (Rhodophyta) led to the discovery of a novel compound, palmyramide A, along with the known compounds curacin D and malyngamide C. The planar structure of palmyramide A was determined by one- and two-dimensional NMR studies and mass spectrometry. Palmyramide A is a cyclic depsipeptide that features an unusual arrangement of three amino acids and three hydroxy acids; one of the hydroxy acids is the rare 2,2-dimethyl-3-hydroxyhexanoic acid unit (Dmhha). The absolute configurations of the six residues were determined by Marfey’s analysis, chiral HPLC analysis, and GC/MS analysis of the hydrolysate. Morphological and phylogenetic studies revealed the sample to be composed of a Lyngbya majuscula−Centroceras sp. association. MALDI-imaging analysis of the cultured L. majuscula indicated that it was the true producer of this new depsipeptide. Pure palmyramide A showed sodium channel blocking activity in neuro-2a ...
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dragonamide e a modified linear lipopeptide from Lyngbya majuscula with antileishmanial activity
Journal of Natural Products, 2010Co-Authors: Marcy J Balunas, Roger G Linington, Kevin Tidgewell, Amanda M Fenner, Luisdavid Urena, Gina Della Togna, Dennis E Kyle, William H. GerwickAbstract:Tropical parasitic and infectious diseases, such as leishmaniasis, pose enormous global health threats, but are largely neglected in commercial drug discovery programs. However, the Panama International Cooperative Biodiversity Group (ICBG) has been working to identify novel treatments for malaria, Chagas' disease, and leishmaniasis through an investigation of plants and microorganisms from Panama. We have pursued activity-guided isolation from an extract of Lyngbya majuscula that was found to be active against leishmaniasis. A new modified linear peptide from the dragonamide series was isolated, dragonamide E (1), along with two known modified linear peptides, dragonamide A (2) and herbamide B (3). Dragonamides A and E and herbamide B exhibited antileishmanial activity with IC50 values of 6.5, 5.1, and 5.9 microM, respectively. Spectroscopic and stereochemical data for dragonamide E (1) and herbamide B (3; the spectroscopic and stereochemical data for this substance is incomplete in the literature) are presented as well as comparisons of biological activity within the dragonamide compound family. Biosynthetic differences among marine compounds with a terminal free amide are also discussed.
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Transcriptional analysis of the jamaicamide gene cluster from the marine cyanobacterium Lyngbya majuscula and identification of possible regulatory proteins
BMC Microbiology, 2009Co-Authors: Adam C Jones, Lena Gerwick, David Gonzalez, Pieter C. Dorrestein, William H. GerwickAbstract:Background The marine cyanobacterium Lyngbya majuscula is a prolific producer of bioactive secondary metabolites. Although biosynthetic gene clusters encoding several of these compounds have been identified, little is known about how these clusters of genes are transcribed or regulated, and techniques targeting genetic manipulation in Lyngbya strains have not yet been developed. We conducted transcriptional analyses of the jamaicamide gene cluster from a Jamaican strain of Lyngbya majuscula, and isolated proteins that could be involved in jamaicamide regulation.
William C. Dennison - One of the best experts on this subject based on the ideXlab platform.
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Discerning the Causes of Toxic Cyanobacteria (Lyngbya majuscula) Blooms in Moreton Bay, Australia
Aquatic Microbial Ecology and Biogeochemistry: A Dual Perspective, 2016Co-Authors: Judith M. O’neil, William C. DennisonAbstract:Blooms of the toxic cyanobacterium, Lyngbya majuscula, were observed in Moreton Bay, Australia, beginning in the late 1990s. These dense blooms led to significant human and ecosystem health impacts. Research on the causes of the bloom focused on nutrient interactions (e.g., nitrogen, phosphorus, and iron) and light availability, in particular, light quality. Light quality investigations reported here were instigated because of the abundance of humic-stained water runoff from the catchment that periodically washed into the primary bloom locations. Light quality experiments were conducted on L. majuscula in aquaria using spectral filters to simulate different light regimes. The most pronounced effect on L. majuscula pigment content and productivity rates was the colored water treatment that simulated the humic-stained runoff. Colored water stimulated pigment content (phycoerythrin and chlorophyll a) and productivity (14C uptake) compared with clear water, turbid water, and a combination of turbid/colored water treatments. Previous research identified the importance of humic compounds in making iron bioavailable to L. majuscula. These results, combined with previous studies of L. majuscula and nutrient interactions, were used to construct a conceptual model of the primary causes of L. majuscula blooms in Moreton Bay, Australia. This model is presented in a diagrammatic format to synthesize research results as to the causes of these cyanobacteria blooms. The Lyngbya majuscula model focuses on having sufficient nutrients, particularly bioavailable iron, in a light climate of colored water. This model for toxic cyanobacteria blooms of L. majuscula in Australia also has relevance in other parts of the world.
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Blooms of the cyanobacterium Lyngbya majuscula in coastal Queensland, Australia: disparate sites, common factors.
Marine pollution bulletin, 2005Co-Authors: Simon Albert, Judith M O'neil, James W Udy, Kathleen S Ahern, Cherie M O'sullivan, William C. DennisonAbstract:During the last decade there has been a significant rise in observations of blooms of the toxic cyanobacterium Lyngbya majuscula along the east coast of Queensland, Australia. Whether the increase in cyanobacterial abundance is a biological indicator of widespread water quality degradation or also a function of other environmental change is unknown. A bioassay approach was used to assesses the potential for runoff from various land uses to stimulate productivity of L. majuscula. In Moreton Bay, L. majuscula productivity was significantly (p
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blooms of the cyanobacterium Lyngbya majuscula in coastal queensland australia disparate sites common factors
Marine Pollution Bulletin, 2005Co-Authors: Simon Albert, Kathleen S Ahern, James Udy, Judith M Oneil, Cherie M Osullivan, William C. DennisonAbstract:During the last decade there has been a significant rise in observations of blooms of the toxic cyanobacterium Lyngbya majuscula along the east coast of Queensland, Australia. Whether the increase in cyanobacterial abundance is a biological indicator of widespread water quality degradation or also a function of other environmental change is unknown. A bioassay approach was used to assesses the potential for runoff from various land uses to stimulate productivity of L. majuscula. In Moreton Bay, L. majuscula productivity was significantly (p < 0.05) stimulated by soil extracts, which were high in phosphorus, iron and organic carbon. Productivity of L. majuscula from the Great Barrier Reef was also significantly (p < 0.05) elevated by iron and phosphorus rich extracts, in this case seabird guano adjacent to the bloom site. Hence, it is possible that other L. majuscula blooms are a result of similar stimulating factors (iron, phosphorus and organic carbon), delivered through different mechanisms.
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Virus-like particles associated with Lyngbya majuscula (Cyanophyta; Oscillatoriacea) bloom decline in Moreton Bay, Australia
Aquatic Microbial Ecology, 2001Co-Authors: Ian Hewson, Judith M. O’neil, William C. DennisonAbstract:Expansive blooms of the toxic cyanobacterium Lyngbya majuscula were observed in 2 shallow water regions of Moreton Bay, Australia. The rapid bloom decline (8 to
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virus like particles associated with Lyngbya majuscula cyanophyta oscillatoriacea bloom decline in moreton bay australia
Aquatic Microbial Ecology, 2001Co-Authors: Ian Hewson, Judith M Oneil, William C. DennisonAbstract:Expansive blooms of the toxic cyanobacterium Lyngbya majuscula were observed in 2 shallow water regions of Moreton Bay, Australia. The rapid bloom decline (8 to <1 km 2 in <7 d) prompted an investigation of the role of cyanophage viruses in the ecophysiology of L. majuscula. Virus-like particles produced by decaying L. majuscula were observed using electron microscopy. The virus-like particles were similar in morphology to viruses in the genus Cyanostyloviridae. The effect of viruses on L. majuscula photosynthesis was investigated by: (1) creating a virus concentrate using tangential-flow ultrafiltration of seawater surrounding L. majuscula; (2) inoculating L. majus- cula with the concentrate; and (3) measuring photosynthetic response using a pulse-amplitude mod- ulated fluorometer. Virus concentrate addition resulted in decreased initial fluorescence, decreased photochemical efficiency and decreased electron transport rate in rapid light curves after 5 d. Viruses present within L. majuscula filaments may play an important role in the bloom dynamics of this eco- logically important cyanobacterium.
Ian R. Tibbetts - One of the best experts on this subject based on the ideXlab platform.
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Lyngbya majuscula blooms and the diet of small subtropical benthivorous fishes
Marine Biology, 2011Co-Authors: Ben L. Gilby, Dana D. Burfeind, Ian R. TibbettsAbstract:Increasing concerns about the ecological impacts of ongoing and possibly worsening blooms of the toxic, carcinogenic cyanobacteria Lyngbya majuscula in Moreton Bay, Australia, led us to assess differences in meiofaunal prey assemblages between bloom and non-bloom substrates and the potential dietary impacts of dense L. majuscula blooms on the omnivorous benthivore, the Eastern Long-finned Goby, Favonigobius lentiginosus and the obligate meiobenthivorous juveniles of Trumpeter Whiting, Sillago maculata . Marked differences in invertebrate communities were found between sandy and L. majuscula bloom foraging substrates, with copepods significantly more abundant (18.49% vs. 70.44% numerical abundance) and nematodes significantly less abundant (55.91% vs. 1.21% numerical abundance) within bloom material. Gut analyses showed that bentho-planktivorous fishes exposed to L. majuscula in captivity had consumed a significantly greater quantity of prey by both total number ( P
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Lyngbya majuscula blooms and the diet of small subtropical benthivorous fishes
Marine Biology, 2010Co-Authors: Ben L. Gilby, Dana D. Burfeind, Ian R. TibbettsAbstract:Increasing concerns about the ecological impacts of ongoing and possibly worsening blooms of the toxic, carcinogenic cyanobacteria Lyngbya majuscula in Moreton Bay, Australia, led us to assess differences in meiofaunal prey assemblages between bloom and non-bloom substrates and the potential dietary impacts of dense L. majuscula blooms on the omnivorous benthivore, the Eastern Long-finned Goby, Favonigobius lentiginosus and the obligate meiobenthivorous juveniles of Trumpeter Whiting, Sillago maculata. Marked differences in invertebrate communities were found between sandy and L. majuscula bloom foraging substrates, with copepods significantly more abundant (18.49% vs. 70.44% numerical abundance) and nematodes significantly less abundant (55.91% vs. 1.21% numerical abundance) within bloom material. Gut analyses showed that bentho-planktivorous fishes exposed to L. majuscula in captivity had consumed a significantly greater quantity of prey by both total number (P < 0.0019) and volume (P < 0.0006) than fish exposed to sand treatments. Thus, it is likely for such fishes that L. majuscula blooms increase rates of prey encounter and consumption, with consequent changes in trophic relationships through shifts in predator–prey interactions between small benthivorous fishes and their meiofaunal prey.
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Feeding preference and deterrence in rabbitfish Siganus fuscescens for the cyanobacterium Lyngbya majuscula in Moreton Bay, south-east Queensland, Australia
Journal of Fish Biology, 2006Co-Authors: Angela Capper, Ian R. Tibbetts, Judith M. O’neilAbstract:Rabbitfish Siganus fuscescens preferences for Lyngbya majuscula collected from three bloom locations in Moreton Bay, Queensland, Australia, were tested along with a range of local plant species in the laboratory. Consumption of L. majuscula by fish did not differ between wild and captive-bred fish (P = 0.152) but did differ between bloom location (P = 0.039). No relationship was found between consumption rates and Lyngbyatoxin-a concentration (r(2) = 0.035, P = 0.814). No correlation existed between C : N and proportion of food consumed when all food types were analysed statistically, whereas a clear correlation was observed when L. majuscula was removed from the calculations. In simulated bloom conditions, fish avoided ingestion of L. majuscula by feeding through gaps in the L. majuscula coverage. Both wild and captive-bred S. fuscescens showed a distinct feeding pattern in 10 day no-choice feeding assays, with less L. majuscula being consumed than the preferred red alga Acanthophora spicifera. Lyngbya majuscula however, was consumed in equal quantities to A. spicifera by wild S. fuscescens when Lyngbyatoxin-a was not detectable. Wild fish probably do not preferentially feed on L. majuscula when secondary metabolites are present and are not severely impacted by large L. majuscula blooms in Moreton Bay. Furthermore, poor feeding performance in both captive-bred and wild S. fuscescens suggests that they would exert little pressure as a top-down control agent of toxic L. majuscula blooms within Moreton Bay. (c) 2006 The Fisheries Society of the British Isles.
Valerie J. Paul - One of the best experts on this subject based on the ideXlab platform.
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pitipeptolides c f antimycobacterial cyclodepsipeptides from the marine cyanobacterium Lyngbya majuscula from guam
Phytochemistry, 2011Co-Authors: Rana Montaser, Valerie J. Paul, Hendrik LueschAbstract:Abstract Pitipeptolides A ( 1 ) and B ( 2 ) are cyclic depsipeptides isolated from the marine cyanobacterium Lyngbya majuscula from Piti Bomb Holes, Guam. Additional analogues have now been isolated by revisiting larger collections of the same cyanobacterium. The four identified analogues, pitipeptolides C–F ( 3 – 6 ), are the tetrahydro analogue ( 3 ), an analogue with a lower degree of methylation ( 4 ) as well as two homologues ( 5 and 6 ) of pitipeptolide A. Their structures were elucidated using 2D NMR experiments, chiral HPLC analysis and comparison with pitipeptolide A. The identified analogues showed weaker cytotoxic activities compared to the two major parent compounds, pitipeptolides A ( 1 ) and B ( 2 ), against HT-29 colon adenocarcinoma and MCF7 breast cancer cells. On the other hand, pitipeptolide F ( 6 ) was the most potent pitipeptolide in a disc diffusion assay against Mycobacterium tuberculosis . The latter finding suggests that the structure of pitipeptolides could be optimized for selective antibacterial activity.
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Pitipeptolides C–F, Antimycobacterial Cyclodepsipeptides from the Marine Cyanobacterium Lyngbya majuscula from Guam
Phytochemistry, 2011Co-Authors: Rana Montaser, Valerie J. Paul, Hendrik LueschAbstract:Abstract Pitipeptolides A ( 1 ) and B ( 2 ) are cyclic depsipeptides isolated from the marine cyanobacterium Lyngbya majuscula from Piti Bomb Holes, Guam. Additional analogues have now been isolated by revisiting larger collections of the same cyanobacterium. The four identified analogues, pitipeptolides C–F ( 3 – 6 ), are the tetrahydro analogue ( 3 ), an analogue with a lower degree of methylation ( 4 ) as well as two homologues ( 5 and 6 ) of pitipeptolide A. Their structures were elucidated using 2D NMR experiments, chiral HPLC analysis and comparison with pitipeptolide A. The identified analogues showed weaker cytotoxic activities compared to the two major parent compounds, pitipeptolides A ( 1 ) and B ( 2 ), against HT-29 colon adenocarcinoma and MCF7 breast cancer cells. On the other hand, pitipeptolide F ( 6 ) was the most potent pitipeptolide in a disc diffusion assay against Mycobacterium tuberculosis . The latter finding suggests that the structure of pitipeptolides could be optimized for selective antibacterial activity.
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malyngamide 3 and cocosamides a and b from the marine cyanobacterium Lyngbya majuscula from cocos lagoon guam
Journal of Natural Products, 2011Co-Authors: Sarath P. Gunasekera, Hendrik Luesch, Rana Montaser, Chivas S Owle, Valerie J. PaulAbstract:Malyngamide 3 (1) and cocosamides A (2) and B (3) were isolated from the lipophilic extract of a collection of Lyngbya majuscula from Cocos Lagoon, Guam. The planar structures of compounds 1−3 were determined by spectroscopic methods. The absolute configuration of 1 was determined by modified Mosher’s method, NOESY data, and comparison with lyngbic acid (4). The absolute configurations of 2 and 3 were assigned by enantioselective HPLC analysis and comparison with the closely related compound pitipeptolide A (5). Compounds 1−3 showed weak cytotoxicity against MCF7 breast cancer and HT-29 colon cancer cells.
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pitiprolamide a proline rich dolastatin 16 analogue from the marine cyanobacterium Lyngbya majuscula from guam
Journal of Natural Products, 2011Co-Authors: Rana Montaser, Valerie J. Paul, Khalil A Abboud, Hendrik LueschAbstract:An unusual cyclic depsipeptide, pitiprolamide (1), was isolated from the marine cyanobacterium Lyngbya majuscula collected at Piti Bomb Holes, Guam. The structure was deduced using NMR, MS, X-ray crystallography, and enantioselective HPLC-MS techniques. Remarkably, proline represents half of the residues forming pitiprolamide (1). Other distinctive features include a 4-phenylvaline (dolaphenvaline, Dpv) moiety initially found in dolastatin 16 and the rare 2,2-dimethyl-3-hydroxyhexanoic acid (Dmhha) unit condensed in a unique sequence in one single molecule. Pitiprolamide (1) showed weak cytotoxic activity against HCT116 colon and MCF7 breast cancer cell lines, as well as weak antibacterial activities against Mycobacterium tuberculosis and Bacillus cereus.
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Malyngolide from the cyanobacterium Lyngbya majuscula interferes with quorum sensing circuitry
Environmental Microbiology Reports, 2010Co-Authors: Sergey Dobretsov, Sarath P. Gunasekera, Max Teplitski, Ali Alagely, Valerie J. PaulAbstract:Extracts of several cyanobacterial species collected from different marine and estuarine locations predominately in Florida (USA), with one sample each from Belize and Oman, were screened for their ability to disrupt quorum sensing (QS) in the reporter strain Chromobacterium violaceum CV017. Inhibitory activities were detected in the ethyl acetate : methanol (1:1) extracts of several Lyngbya spp., and extracts of Lyngbya majuscula contained the strongest QS inhibitory activities. Extracts of L. majuscula from the Indian River Lagoon, FL, USA, were further purified by bioassay-guided fractionation. The antibiotic malyngolide (MAL) was identified as a QS inhibitor. Activity of MAL was investigated using N-acyl homoserine lactone (AHL) reporters based on the LasR receptor of Pseudomonas aeruginosa. MAL at concentrations ranging from 3.57 µM to 57 µM (EC50 = 12.2 ± 1.6 µM) inhibited responses of the LasR reporters without affecting bacterial growth. MAL inhibited (EC50 = 10.6 ± 1.8 µM) Las QS-dependent production of elastase by P. aeruginosa PAO1. We propose that this QS inhibitor plays a role in controlling interactions of heterotrophic bacteria associated with the cyanobacterium L. majuscula.
Tadeusz F Molinski - One of the best experts on this subject based on the ideXlab platform.
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Caylobolide A, a unique 36-membered macrolactone from a Bahamian Lyngbya majuscula.
Organic letters, 2002Co-Authors: John B Macmillan, Tadeusz F MolinskiAbstract:[structure: see text]. A new 36-membered macrolactone, (25S,27S,29S,33S)-caylobolide A, was isolated from the Bahamian cyanobacterium Lyngbya majuscula. The structure of caylobolide contains an unprecedented repeated unit-a contiguous pentad of 1,5 diols-and a 1,3,5-triol. The relative steroechemistry of the 1,3,5-triol was determined using Kishi's Universal NMR database, and absolute stereochemistry at C25,27,29 and C33 were determined by Mosher's analysis. Caylobolide A exhibited in vitro cytotoxicity against human colon tumor cells (IC50 HCT 116, 9.9 microM).
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caylobolide a a unique 36 membered macrolactone from a bahamian Lyngbya majuscula
Organic Letters, 2002Co-Authors: John B Macmillan, Tadeusz F MolinskiAbstract:A new 36-membered macrolactone, (25S,27S,29S,33S)-caylobolide A, was isolated from the Bahamian cyanobacterium Lyngbya majuscula. The structure of caylobolide contains an unprecedented repeated unita contiguous pentad of 1,5 diolsand a 1,3,5-triol. The relative steroechemistry of the 1,3,5-triol was determined using Kishi's Universal NMR database, and absolute stereochemistry at C25,27,29 and C33 were determined by Mosher's analysis. Caylobolide A exhibited in vitro cytotoxicity against human colon tumor cells (IC50 HCT 116, 9.9 μM).
