CONCLUSIONS: The results suggest that the enriched DOM in stationary phase of phytoplankton bloom is a result of ammonium depletion. This environment drives genomic streamlining of opportunistic bacteria to exploit their preferred nitrogen-containing compounds and maintain nutrient cycling. Video abstract.
Category: Dinoflagellate genomics
Mar 22
Marinobacter alexandrii sp. nov., a novel yellow-pigmented and algae growth-promoting bacterium isolated from marine phycosphere microbiota
The marine phycosphere harbors unique cross-kingdom associations with ecological relevance. During investigating the diversity of phycosphere microbiota of marine harmful algal blooms dinoflagellates, a faint yellow-pigmented bacterium, designated as strain LZ-8, was isolated from paralytic shellfish poisoning toxin-producing dinoflagellate Alexandrium catenella LZT09. The new isolate appeared to have growth-promoting potential toward its algal host. Molecular analysis using 16S rRNA gene,…
Mar 20
Combined characterization of a new member of Marivita cryptomonadis strain LZ-15-2 isolated from cultivable phycosphere microbiota of highly toxic HAB dinoflagellate Alexandrium catenella LZT09
During our conveying the microbial structures of phycosphere microbiota (PM) derived from diverse marine harmful algal bloom (HAB) dinoflagellates, a new rod-sharped, white-colored cultivable bacterial strain, designated as LZ-15-2, was isolated from the PM of highly toxic Alexandrium catenella LZT09. Phylogenetic analysis of 16S rRNA gene sequence indicated that strain LZ-15-2 belonged to the genus Marivita within the family Rhodobacteraceae, and demonstrated the highest gene similarity of…
Mar 18
Muricauda amphidinii sp. nov., a novel marine bacterium isolated from the phycosphere of dinoflagellate Amphidinium carterae
A Gram-stain-negative, aerobic, rod-shaped and non-motile bacterium was isolated from a liquid culture of dinoflagellate Amphidinium carterae and further designated as LMIT004^(T). Optimal growth was observed at 25 °C, pH 7.0 and in the presence of 2 % (w/v) NaCl. Oxidase and catalase were positive. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain LMIT004^(T) showed high similarities to type strains Muricauda nanhaiensis SM17004^(T) (96.77 %) and Muricauda aquimarina…
Mar 15
From the <em>sxtA4</em> Gene to Saxitoxin Production: What Controls the Variability Among <em>Alexandrium minutum</em> and <em>Alexandrium pacificum</em> Strains?
Paralytic shellfish poisoning (PSP) is a human foodborne syndrome caused by the consumption of shellfish that accumulate paralytic shellfish toxins (PSTs, saxitoxin group). In PST-producing dinoflagellates such as Alexandrium spp., toxin synthesis is encoded in the nuclear genome via a gene cluster (sxt). Toxin production is supposedly associated with the presence of a 4th domain in the sxtA gene (sxtA4), one of the core genes of the PST gene cluster. It is postulated that gene expression in…
Mar 09
Intracellular pH regulation: characterization and functional investigation of H<sup>+</sup> transporters in Stylophora pistillata
CONCLUSIONS: In this study, we provide the first characterization of H^(+) transporters that might contribute to the homeostatic acid-base balance in coral cells. This work will enrich the knowledge of the basic aspects of coral biology and has important implications for our understanding of how corals regulate their intracellular environment.
Mar 06
RNA Viruses in Aquatic Unicellular Eukaryotes
Increasing sequence information indicates that RNA viruses constitute a major fraction of marine virus assemblages. However, only 12 RNA virus species have been described, infecting known host species of marine single-celled eukaryotes. Eight of these use diatoms as hosts, while four are resident in dinoflagellate, raphidophyte, thraustochytrid, or prasinophyte species. Most of these belong to the order Picornavirales, while two are divergent and fall into the families Alvernaviridae and…
Feb 25
In vitro investigation of the genotoxicity of portimine, a cyclic imine toxin produced by the dinoflagellate Vulcanodinium rugosum, on human hepatic HepaRG cells
Portimine, a recently identified cyclic imine produced by the dinoflagellate Vulcanodinium rugosum, has been described as a potent apoptotic agent in contrast to most of the cyclic imines that are well-known to be neurological toxins. As apoptosis can be a consequence of a high level of DNA lesions, we investigated the responses of portimine on several endpoints aimed at detecting DNA damage in the hepatic cell line HepaRG. Portimine induced phosphorylation of H2AX, which could possibly be…
Feb 23
Color morphs of the coral, Acropora tenuis, show different responses to environmental stress and different expression profiles of fluorescent-protein genes
Corals of the family Acroporidae are key structural components of reefs that support the most diverse marine ecosystems. Due to increasing anthropogenic stresses, coral reefs are in decline. Along the coast of Okinawa, Japan, three different color morphs of Acropora tenuis have been recognized for decades. These include brown (N morph), yellow green (G), and purple (P) forms. The tips of axial polyps of each morph exhibit specific fluorescence spectra. This attribute is inherited asexually, and…
Feb 20
Protistology and Cell Biology at the Marine Arago Laboratory of Banyuls-sur-Mer (1961-2000): Personal Recollections.
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Protistology and Cell Biology at the Marine Arago Laboratory of Banyuls-sur-Mer (1961-2000): Personal Recollections.
Protist. 2021 Jan 28;172(1):125792
Authors: Soyer-Gobillard MO
Abstract
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