Presence of Ecophysiologically Diverse Populations within Cobetia marina Strains Isolated from Marine Invertebrate, Algae and the Environments

Over the last decade, taxonomic surveys have recovered sixteen strains of Halomonas-like marine heterotrophic bacteria from different ecological habitats. The sixteen strains were isolated from three N.W. Pacific Ocean habitats: seawater, the mussel Crenomytilus grayanus and the degraded thallus of brown alga Fucus evanescens. These strains were subjected to a taxonomic investigation of their phenotypic/physiological, genetic, and phylogenetic features. Analysis indicates these bacteria belong to Cobetia marina. The study found all strains tolerated CdCl2 concentrations up to 875 mM. Taxonomically, the sixteen strains belong to the same species, nevertheless, their physiological features revealed distinguishing characteristics. For instance, strain KMM 296, recovered from the mussel Crenomytilus grayanus, was distinct from other C. marina strains by its ability to produce highly active alkaline phosphatase. The majority of C. marina strains that were isolated from degraded alga thallus appeared to have a particular metabolic specialisation by utilizing a range of easily assimilable monosaccharides. Notably, despite a high level of genetic similarity (80% of DNA relatedness), the phenotypic features of the strains isolated from degraded alga thallus differed with the type strain C. marina LMG 2217T. These differences suggest an ecologically adapted population of C. marina at a subspecies level

Tolerance to cadmium of free-living and associated with marine animals and eelgrass marine gamma-proteobacteria

The tolerance to Cd2+ and possible mechanisms of Cd2+ detoxification by 178 free-living bacteria isolated from sea water, associated with marine animals (a mussel Crenomytilus grayanus, a scallop Patinopecten yessoensis), and eelgrass Zostera marina collected in The Sea of Japan and The Sea of Okhotsk have been studied. The concentrations of 25 and 50 mg Cd2+/L were highly toxic and inhibited the growth from 54% to 78% of the total bacteria studied. The free-living bacteria isolated from seawater samples (up to 50%) were tolerant to high concentrations of cadmium. Marine gamma-proteobacteria tolerated Cd2+ by the activation of different detoxifying mechanisms. The strain Halomonas sp. KMM 734 isolated from seawater prevented the uptake of Cd2+ into bacterial cells. The chromosomal cadmium resistance system of Pseudoalteromonas citrea KMM 461 and Marinobacter sp. KMM 181 was found to be similar to class III metallothioneins (also known as phytochelatins)

Presence of Ecophysiologically Diverse Populations within Cobetia marina Strains Isolated from Marine Invertebrate, Algae and the Environments

Over the last decade, taxonomic surveys have recovered sixteen strains of Halomonas-like marine heterotrophic bacteria from different ecological habitats. The sixteen strains were isolated from three N.W. Pacific Ocean habitats: seawater, the mussel Crenomytilus grayanus and the degraded thallus of brown alga Fucus evanescens. These strains were subjected to a taxonomic investigation of their phenotypic/physiological, genetic, and phylogenetic features. Analysis indicates these bacteria belong to Cobetia marina. The study found all strains tolerated CdCl2 concentrations up to 875 mM. Taxonomically, the sixteen strains belong to the same species, nevertheless, their physiological features revealed distinguishing characteristics. For instance, strain KMM 296, recovered from the mussel Crenomytilus grayanus, was distinct from other C. marina strains by its ability to produce highly active alkaline phosphatase. The majority of C. marina strains that were isolated from degraded alga thallus appeared to have a particular metabolic specialisation by utilizing a range of easily assimilable monosaccharides. Notably, despite a high level of genetic similarity (80% of DNA relatedness), the phenotypic features of the strains isolated from degraded alga thallus differed with the type strain C. marina LMG 2217T. These differences suggest an ecologically adapted population of C. marina at a subspecies level