Dinoroseobacter shibae gen. nov., sp. nov., a new aerobic phototrophic bacterium isolated from dinoflagellates

Abstract

A novel group of aerobic anoxygenic phototrophic bacteria was isolated from marine dinoflagellates, and two strains were characterized in detail. Cells were Gram-negative cocci or ovoid rods and were motile by means of a single, polarly inserted flagellum. They were obligate aerobes requiring 1-7 % salinity. The optimal pH range for growth was 6?5-9?0 and the temperature optimum was 33 6C. The bacteria contained bacteriochlorophyll a and spheroidenone as the only carotenoid. The in vivo absorption spectrum displayed two maxima in the infrared region at 804 and 868 nm. The distinct 804 nm band indicates the presence of light-harvesting system 2. Various organic carbon sources were assimilated, including many carboxylic acids, glucose and glycerol, but not butyrate, ethanol or methanol. Dissimilatory nitrate reduction was found for both strains. The physiological characteristics of the new strains resembled those of Roseobacter denitrificans, but there were differences in the lipid composition. Based on 16S rRNA gene sequence analysis the new strains are relatively distant from other recognized species, with the closest relatives Jannaschia helgolandensis, Ruegeria atlantica and Rhodobacter veldkampii showing 94?1-93?4 % similarity. Similarity to Roseobacter denitrificans was only 92?2 %, in line with numerous other species of the Roseobacter group. Therefore, it is proposed to classify the strains in a new genus and species within the Roseobacter clade, Dinoroseobacter shibae gen. nov., sp. nov. The type strain is DFL 12 T (=DSM 16493 T =NCIMB 14021 T ).

Oceanibaculum indicum gen. nov., sp. nov., isolated from deep seawater of the Indian Ocean

“…Antibiotic susceptibility tests were performed by the disc diffusion method as described by Shieh et al (2003). Bacteriochlorophyll a content was determined as described by Biebl et al (2005). Other biochemical tests were carried out by using API 20NE and API ZYM strips (bioMérieux) according to the manufacturer's instructions, and by using the Biolog GN2 microplate system according to Ivanova et al (1998).…”

You are what you talk: quorum sensing induces individual morphologies and cell division modes in Dinoroseobacter shibae

“…shibae is a representative of the Roseobacter clade, a large, diverse and ecologically important phylogenetic cluster of Alphaproteobacteria (Wagner-Döbler and Biebl, 2006;Brinkhoff et al, 2008), abundant in temperate and polar marine habitats (Selje et al, 2004;Giebel et al, 2011). It was isolated from the dinoflagellate Prorocentrum lima (Biebl et al, 2005) and lives in symbiosis with marine algae (Wagner-Döbler et al, 2010). Under optimal growth conditions a remarkable variability in cell size and morphology can be observed.…”

First Annual U.S. Department of Energy Office of Science Joint Genome Institute User Meeting, March 29-April 1, 2006

“…This confirmed that many hypothetical proteins are expressed at detectable levels in the major biofilm organisms, and also indicated that a majority of abundant extracellular proteins are novel. 2 This groundwork has enabled us to examine proteins expressed in biofilms harvested from several neighboring locations, in carefully measured geochemical conditions, using a combination of chromatographic techniques, MS identification and computational analyses/predictions. 3 These methods provide us with a powerful approach to isolate many of the novel proteins along with any known proteins associated with them, and to begin assigning functions using biochemical assays.…”

“…First described 15 years ago, the genus Roseobacter has become the core of a group of marine bacteria which are the focus of intense research because of their taxonomic diversity and abundance in the world's oceans as well as their important contribution to the global carbon and sulfur cycles and thus to climate change. Dinoroseobacter shibae is a novel genus within this group that was isolated from toxic marine dinoflagellates 2 and is able to perform aerobic anoxygenic photosynthesis, a way of generating energy using bacteriochlorophyll a which contributes up to 10% to the primary production in the ocean and is presently poorly understood. Dinoroseobacter shibae carries the pufLM genes of the photosynthesis reaction center and has fully functional light harvesting complexes I and II including bacteriochlorophyll a synthesis 4 .…”