Oceanisphaera pacifica sp. nov., isolated from the intestine of Trichiurus japonicus

Phenotypic and Genomic Characterization of Oceanisphaera submarina sp. nov. Isolated from the Sea of Japan Bottom Sediments

A Gram-negative aerobic, motile bacterium KMM 10153T was isolated from bottom sediment sampled from the Sea of Japan at a depth of 256 m, Russia. Strain KMM 10153T grew in 0-12% NaCl at temperatures ranging from 4 to 42 °C and produced brown diffusible pigments. Based on the 16S rRNA gene and whole genome sequences analyses, novel bacterium KMM 10153T was affiliated with the genus Oceanisphaera (phylum Pseudomonadota) showing the highest 16S rRNA gene sequence similarities of 98.94% to Oceanisphaera arctica KCTC 23013T, 98.15% to Oceanisphaera donghaensis BL1T, and similarity values of <98% to other validly described Oceanisphaera species. The pairwise Average Nucleotide Identity (ANI) and Average Amino Acid Identity (AAI) values between the novel strain KMM 10153T and the three closest type strains Oceanishaera arctica KCTC 23013T, Oceanisphaera litoralis DSM 15406T and Oceanisphaera sediminis JCM 17329T were 89.4%, 89.1%, 87.41%, and 90.7%, 89.8%, 89.7%, respectively. The values of digital DNA-DNA hybridization (dDDH) were below 39.3%. The size of the KMM 10153T draft genome was 3,558,569 bp, and the GC content was 57.5%. The genome of KMM 10153T harbors 343 unique genes with the most abundant functional classes consisting of transcription, mobilome, amino acid metabolism, and transport. Strain KMM 10153T contained Q-8 as the predominant ubiquinone and C16:1ω7c, C16:0, and C18:1ω7c as the major fatty acids. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and phosphatidic acid. Based on the distinctive phenotypic characteristics and the results of phylogenetic and genomic analyses, the marine bacterium KMM 10153T could be classified as a novel Oceanisphaera submarina sp. nov. The type strain of the species is strain KMM 10153T (=KCTC 8836T).

Complete genome sequence of the novel Antarctic Oceanisphaera sp. IT1-181 that carried five plasmids

Bacteria of the genus Oceanisphaera in the class Gammaproteobacteria are widely distributed in marine environments. Oceanisphaera sp. IT1-181 was isolated from intertidal sediment in the coastal region of the Chinese Great Wall Station on the Fildes Peninsula, King George Island, Antarctica. Here, we sequenced the complete genome of strain IT1-181, which contained a single chromosome of 3,572,184 bp (G + C content of 49.89 mol%) with five plasmids. A total of 3229 protein-coding genes, 88 tRNA genes, and 25 rRNA genes were obtained. Genome sequence analysis revealed that strain IT1-181 was not only a potentially novel species of the genus Oceanisphaera, but also harbored genes involved in biosynthesizing ectoine as well as poly-β-hydroxybutyric acid (PHB). In addition, genes of a complete type I-E CRISPR-Cas system were found in the bacterium. The results indicate the potential of strain Oceanisphaera sp. IT1-181 in biotechnology and are helpful for us understanding its ecological roles in the changing Antarctic intertidal zone environment.