RESUMO
A Gram-negative, motile, rod-shaped bacterial strain, HP15(T), was isolated from aggregates taken from surface waters of the German Wadden Sea (German Bight). Of 82 marine isolates, HP15(T) was chosen for further study because of its high potential to induce production of transparent exopolymeric particles and aggregate formation while interacting with the diatom Thalassiosira weissflogii. HP15(T) grew optimally at 34-38 °C and pH 7.0-8.5, and was able to tolerate salt concentrations of 0.5-20% (w/v) NaCl. HP15(T) was characterized chemotaxonomically by possessing ubiquinone-9 as the major respiratory lipoquinone, as well as C(16:0), C(18:1)ω9c and C(16:1)ω7c/iso-C(15:0) 2-OH as the predominant fatty acids. The DNA G+C content of strain HP15(T) was 56.9 mol%. The closest relative based on 16S rRNA gene sequence analysis was the type strain of Marinobacter flavimaris, with 99% similarity. Whole-genome relatedness values of HP15(T) to the type strains of M. flavimaris, Marinobacter salsuginis, Marinobacter lipolyticus and Marinobacter algicola were less than 70%, as determined by DNA-DNA hybridization. On the basis of phenotypic and chemotaxonomic properties as well as phylogenetic analyses, the isolate represents a novel species, Marinobacter adhaerens sp. nov.; the type strain is HP15(T) (=DSM 23420(T)=CIP 110141(T)).
Assuntos
Diatomáceas/microbiologia , Marinobacter/classificação , Marinobacter/isolamento & purificação , Água do Mar/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Ácidos Graxos/análise , Concentração de Íons de Hidrogênio , Locomoção , Marinobacter/genética , Marinobacter/fisiologia , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Filogenia , Quinonas/análise , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Cloreto de Sódio/metabolismo , TemperaturaRESUMO
Marinobacter adhaerens HP15 is the type strain of a newly identified marine species, which is phylogenetically related to M. flavimaris, M. algicola, and M. aquaeolei. It is of special interest for research on marine aggregate formation because it showed specific attachment to diatom cells. In vitro it led to exopolymer formation and aggregation of these algal cells to form marine snow particles. M. adhaerens HP15 is a free-living, motile, rod-shaped, Gram-negative gammaproteobacterium, which was originally isolated from marine particles sampled in the German Wadden Sea. M. adhaerens HP15 grows heterotrophically on various media, is easy to access genetically, and serves as a model organism to investigate the cellular and molecular interactions with the diatom Thalassiosira weissflogii. Here we describe the complete and annotated genome sequence of M. adhaerens HP15 as well as some details on flagella-associated genes. M. adhaerens HP15 possesses three replicons; the chromosome comprises 4,422,725 bp and codes for 4,180 protein-coding genes, 51 tRNAs and three rRNA operons, while the two circular plasmids are ~187 kb and ~42 kb in size and contain 178 and 52 protein-coding genes, respectively.
