asitologie , virologie rst description of a new uncultured purple sulfur bacterium lonizing marine mangrove sediment in the Caribbean : lochromatium-like PSB from Guadeloupe scription d ’ une bactérie sulfureuse pourpre non cultivable colonisant sédiments des mangroves marine dans

Here, we report the first description of a marine purple sulfur bacterium (PSB) from sulfide-rich sediments of a marine mangrove in the Caribbean. TEM shows that this new isolate contains intracytoplasmic vesicular membrane systems (containing bacteriochlorophyll a) and larger internal sulfur granules, confirmed by EDXS analyses performed using ESEM. The sulfur distribution and mapping obtained for this PSB strain has allowed us to conclude that elemental sulfur is formed as an intermediate oxidation product and stored intracellularly. SEM shows that the bacterial cells are ovoid and extremely motile via lophotrichous flagella. Phylogenetic characterization, based on the analysis of 16S rDNA and functional gene pufM sequences, demonstrate that this strain belongs to the Chromatiaceae and may be a representative of a new species of the genus Halochromatium. Thus, reduced sediments of marine mangrove represent a sulfide-rich environment that sustains the development ofChromatiaceae, in addition to sulfuroxidizing bacteria and cyanobacteria, as previously reported. C 2018 Published by Elsevier Masson SAS on behalf of Académie des sciences. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/