Lyngbya

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Kiyotake Suenaga - One of the best experts on this subject based on the ideXlab platform.

Osamu Ohno - One of the best experts on this subject based on the ideXlab platform.

Valerie J. Paul - One of the best experts on this subject based on the ideXlab platform.

  • Uncovering cryptic diversity of Lyngbya: the new tropical marine cyanobacterial genus Dapis (Oscillatoriales)
    Journal of Phycology, 2018
    Co-Authors: Niclas Engene, Ana Tronholm, Valerie J. Paul
    Abstract:

    Cyanobacteria comprise an extraordinarily diverse group of microorganisms and, as revealed by increasing molecular information, this biodiversity is even more extensive than previously estimated. In this sense, the cyanobacterial genus Lyngbya is a highly polyphyletic group composed of many unrelated taxa with morphological similarities. In this study, the new genus Dapis was erected from the genus Lyngbya, based on a combined molecular, chemical, and morphological approach. Herein, two new species of cyanobacteria are described: D. pleousa and D. pnigousa. Our analyses found these species to be widely distributed and abundant in tropical and subtropical marine habitats. Seasonally, both species have the ability to form extensive algal blooms in marine habitats: D. pleousa in shallow-water, soft bottom habitats and D. pnigousa on coral reefs below depths of 10 m. Electron microscopy showed that D. pleousa contains gas vesicles, a character not previously reported in Lyngbya. These gas vesicles, in conjunction with a mesh-like network of filaments that trap oxygen released from photosynthesis, provide this species with an unusual mechanism to disperse in coastal marine waters, allowing D. pleousa to be present in both benthic and planktonic forms. In addition, both D. pleousa and D. pnigousa contained nitrogen-fixing genes as well as bioactive secondary metabolites. Several specimens of D. pnigousa biosynthesized the secondary metabolite lyngbic acid, a molecule that has also been isolated from many other marine cyanobacteria. Dapis pleousa consistently produced the secondary metabolite malyngolide, which may provide a promising chemotaxonomic marker for this species.

  • Malyngolide from the cyanobacterium Lyngbya majuscula interferes with quorum sensing circuitry
    Environmental Microbiology Reports, 2010
    Co-Authors: Sergey Dobretsov, Sarath P. Gunasekera, Max Teplitski, Ali Alagely, Valerie J. Paul
    Abstract:

    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.

  • Effects of nutrient enrichment of the cyanobacterium Lyngbya sp. on growth, secondary metabolite concentration and feeding by the specialist grazer Stylocheilus striatus
    Marine Ecology Progress Series, 2009
    Co-Authors: Karen E. Arthur, Valerie J. Paul, Hans W. Paerl, Judith M. O’neil, Jennifer J. Joyner, Theresa Meickle
    Abstract:

    Harmful blooms of the benthic cyanobacteria Lyngbya spp. are increasing in coastal marine habitats. Nutrient enrichment has been implicated in bloom formation; however, the effects of nutrient enrichment on secondary metabolite concentrations and the resulting palatability of Lyngbya spp. are not known. Using nutrient bioassays, we examined the effects of nitrogen (N), phosphorus (P) and chelated iron (Fe) on growth and secondary metabolite concentration in Lyngbya sp. collected from reefs in Broward County, Florida. The consequences of these nutrient additions on feeding be- havior of a major specialist opisthobranch grazer, Stylocheilus striatus, were examined. Chelated Fe additions (+FeEDTA) significantly increased Lyngbya sp. growth, while additions of N, P and chelated Fe combined (+All) resulted in significantly lower concentrations of microcolin A than in the control. Overall, there was a negative correlation between growth and total concentrations of microcolins A and B. When crude extracts from the control, +FeEDTA and +All treatments of the Lyngbya sp. bioas- say were offered to S. striatus in artificial food, they consumed greater quantities of the control and +FeEDTA treatments than the +All. These results provide the first evidence that changes in nutrient availability can affect secondary metabolite concentrations in marine Lyngbya spp. and support previ- ous studies that show that Fe can stimulate growth in benthic marine cyanobacteria. This study also demonstrates quantifiable changes in feeding behavior by a specialist grazer in response to changes in the nutrient conditions under which Lyngbya sp. grows and underscores the need to consider sec- ondary metabolite concentrations, and their effect on grazers, when managing harmful algal blooms.

  • Grazer Interactions with Four Species of Lyngbya in Southeast Florida
    Harmful Algae, 2008
    Co-Authors: Angela Capper, Valerie J. Paul
    Abstract:

    Blooms of the toxic cyanobacteria Lyngbya spp. have been increasing in frequency and severity in southeast Florida in recent years. Lyngbya produces many active secondary metabolites which often act as feeding deterrents to generalist herbivores, possibly increasing the longevity of these nuisance blooms. Whilst diverse arrays of small invertebrate consumers are often found in association with Lyngbya, little is known of their grazing selectivity among species of Lyngbya. This study examines the feeding preference of grazers for four local Lyngbya species (Lyngbya majuscula, Lyngbya confervoides, Lyngbya polychroa and Lyngbya spp.). Stylocheilus striatus and Haminoea antillarum showed no dietary selectivity between L. polychroa, L. majuscula and Lyngbya spp. in multiple choice feeding assays, whereas Bulla striata showed a distinct preference for L. polychroa (P < 0.001). To determine whether preference might be related to species-specific secondary metabolites, L. majuscula, L. confervoides and L. polychroa non-polar and polar extracts were incorporated into artificial diets and offered to a range of mesograzers. No significant difference was noted in feeding stimulation or deterrence amongst extracts and the controls for any of the grazers. When fed a monospecific diet of L. polychroa, S. striatus consumed more (P < 0.001) and attained a higher daily biomass (P = 0.004) than S. striatus fed L. confervoides. As L. polychroa and L. confervoides often co-exist on local coral reefs and yield dense numbers of S. striatus, host switching to a more palatable species of Lyngbya may have important implications regarding top-down control of local blooms leading to proliferation of one species and decimation of another. S. striatus fed a diet of L. polychroa consumed more (P = 0.003), had a greater increase in body mass (P = 0.020) and higher conversion efficiency (P = 0.005) than those fed L. confervoides regardless of host origin. Possible explanations for host switching between species of Lyngbya related to morphology, toxicity and nutrient requirements for growth are discussed.

  • morphological chemical and genetic diversity of tropical marine cyanobacteria Lyngbya spp and symploca spp oscillatoriales
    Applied and Environmental Microbiology, 2004
    Co-Authors: Robert W Thacker, Valerie J. Paul
    Abstract:

    Although diverse natural products have been isolated from the benthic, filamentous cyanobacterium Lyngbya majuscula, it is unclear whether this chemical variation can be used to establish taxonomic relationships among disparate collections. We compared morphological characteristics, secondary-metabolite compositions, and partial 16S ribosomal DNA (rDNA) sequences among several collections of L. majuscula Gomont, Lyngbya spp., and Symploca spp. from Guam and the Republic of Palau. The morphological characteristics examined were cell length, cell width, and the presence or absence of a calyptra. Secondary metabolites were analyzed by two-dimensional thin-layer chromatography. Each collection possessed a distinct cellular morphology that readily distinguished Lyngbya spp. from Symploca spp. Each collection yielded a unique chemotype, but common chemical characteristics were shared among four collections of L. majuscula. A phylogeny based on secondary-metabolite composition supported the reciprocal monophyly of Lyngbya and Symploca but yielded a basal polytomy for Lyngbya. Pairwise sequence divergence among species ranged from 10 to 14% across 605 bp of 16S rDNA, while collections of L. majuscula showed 0 to 1.3% divergence. Although the phylogeny of 16S rDNA sequences strongly supported the reciprocal monophyly of Lyngbya and Symploca as well as the monophyly of Lyngbya bouillonii and L. majuscula, genetic divergence was not correlated with chemical and morphological differences. These data suggest that 16S rDNA sequence analyses do not predict chemical variability among Lyngbya species. Other mechanisms, including higher rates of evolution for biosynthetic genes, horizontal gene transfer, and interactions between different genotypes and environmental conditions, may play important roles in generating qualitative and quantitative chemical variation within and among Lyngbya species.

William H. Gerwick - One of the best experts on this subject based on the ideXlab platform.

  • Wewakamide A and guineamide G, cyclic depsipeptides from the marine cyanobacteria Lyngbya semiplena and Lyngbya majuscula.
    Journal of Microbiology and Biotechnology, 2011
    Co-Authors: Bingnan Han, Harald Gross, Kerry L. Mcphail, Doug Goeger, Claudia S. Maier, William H. Gerwick
    Abstract:

    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.

  • Underestimated biodiversity as a major explanation for the perceived rich secondary metabolite capacity of the cyanobacterial genus Lyngbya.
    Environmental Microbiology, 2011
    Co-Authors: Niclas Engene, Eduardo Esquenazi, Pieter C. Dorrestein, Hyukjae Choi, Erin C. Rottacker, Mark H. Ellisman, William H. Gerwick
    Abstract:

    Summary Marine cyanobacteria are prolific producers of bioactive secondary metabolites responsible for harmful algal blooms as well as rich sources of promising biomedical lead compounds. The current study focused on obtaining a clearer understanding of the remarkable chemical richness of the cyanobacterial genus Lyngbya. Specimens of Lyngbya from various environmental habitats around Curacao were analysed for their capacity to produce secondary metabolites by genetic screening of their biosynthetic pathways. The presence of biosynthetic pathways was compared with the production of corresponding metabolites by LC-ESI-MS2 and MALDI-TOF-MS. The comparison of biosynthetic capacity and actual metabolite production revealed no evidence of genetic silencing in response to environmental conditions. On a cellular level, the metabolic origin of the detected metabolites was pinpointed to the cyanobacteria, rather than the sheath-associated heterotrophic bacteria, by MALDI-TOF-MS and multiple displacement amplification of single cells. Finally, the traditional morphology-based taxonomic identifications of these Lyngbya populations were combined with their phylogenetic relationships. As a result, polyphyly of morphologically similar cyanobacteria was identified as the major explanation for the perceived chemical richness of the genus Lyngbya, a result which further underscores the need to revise the taxonomy of this group of biomedically important cyanobacteria.

  • 16S rRNA GENE HETEROGENEITY IN THE FILAMENTOUS MARINE CYANOBACTERIAL GENUS Lyngbya
    Journal of Phycology, 2010
    Co-Authors: Niclas Engene, R. Cameron Coates, William H. Gerwick
    Abstract:

    The SSU (16S) rRNA gene was used to investigate the phylogeny of the cyanobacterial genus Lyngbya as well as examined for its capacity to discriminate between different marine species of Lyngbya .W e show that Lyngbya forms a polyphyletic genus composed of a marine lineage and a halophilic ⁄brackish ⁄freshwater lineage. In addition, we found morphological and genetic evidence that Lyngbya spp. often grow in association with other microorganisms, in particular smaller filamentous cyanobacteria such as Oscillatoria, and propose that these associated microorganisms have led to extensive phylogenetic confusion in identification of Lyngbya spp. At the species level, the phylogenetic diversity obtained from the comparison of 16S rRNA genes exceeded morphological diversity in Lyngbya. However, the expectation that this improved phylogeny would be useful to species and subspecies identification was eliminated by the fact that phylogenetic species did not correlate in any respect with the species obtained from current taxonomic systems. In addition, phylogenetic identification was adversely affected by the presence of multiple gene copies within individual Lyngbya colonies. Analysis of clonal Lyngbya cultures and multiple displacement amplified (MDA) single-cell genomes revealed that Lyngbya genomes contain two 16S rRNA gene copies, and that these typically are of variable sequence. Furthermore, intragenomic and interspecies 16S rRNA gene heterogeneity was approximately of the same magnitude. Hence, the intragenomic heterogeneity of the 16S rRNA gene overestimates the microdiversity of different strains and does not accurately reflect speciation within cyanobacteria, including the genus Lyngbya.

  • Transcriptional analysis of the jamaicamide gene cluster from the marine cyanobacterium Lyngbya majuscula and identification of possible regulatory proteins
    BMC Microbiology, 2009
    Co-Authors: Adam C Jones, Lena Gerwick, David Gonzalez, Pieter C. Dorrestein, William H. Gerwick
    Abstract:

    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.

  • Apratoxin D, a potent cytotoxic cyclodepsipeptide from papua new guinea collections of the marine cyanobacteria Lyngbya majuscula and Lyngbya sordida.
    Journal of Natural Products, 2008
    Co-Authors: Marcelino Gutiérrez, Niclas Engene, Takashi L. Suyama, Joshua S. Wingerd, Teatulohi Matainaho, William H. Gerwick
    Abstract:

    Cancer cell toxicity-guided fractionation of extracts of the Papua New Guinea marine cyanobacteria Lyngbya majuscula and Lyngbya sordida led to the isolation of apratoxin D (1). Compound 1 contains the same macrocycle as apratoxins A and C but possesses the novel 3,7-dihydroxy-2,5,8,10,10-pentamethylundecanoic acid as the polyketide moiety. The planar structures and stereostructures of compound 1 were determined by extensive 1D and 2D NMR and MS data analyses and by comparison with the spectroscopic data of apratoxins A and C. Apratoxin D (1) showed potent in vitro cytotoxicity against H-460 human lung cancer cells with an IC50 value of 2.6 nM.

Arihiro Iwasaki - One of the best experts on this subject based on the ideXlab platform.

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