Marinomonas vulgaris sp. nov., a marine bacterium isolated from seawater in a coastal intertidal zone of Zhoushan island.

A Marinomonas-like, Gram-stain-negative, strictly aerobic and rod to ovoid-shaped bacterium, designated as strain A79T, was isolated from the seawater mixtures of oyster shells and brown algae in a coastal intertidal zone of Zhoushan, China. The strain was positive for oxidase and catalase. Colonies grown on marine agar for 48 h were round, milky white, smooth and moist with the diameter of 2-3 mm. Growth was observed at 15-30 °C (optimum, 25℃), pH 5.5-9.5 (optimum, pH 8.5) and with 0.5-8% (w/v) NaCl (optimum, 2-2.5%). The G + C content based on the genome sequence was 46.0%. The only respiratory quinone was Q-8. The main polar lipids contained phosphatidylglycerol, phosphatidylethanolamine, unidentified glycolipids, unidentified phospholipid and three unidentified lipids. The major fatty acids (> 10%) were C16:0, Summed feature 3 (comprising C16:1 ω6c and/or C16:1 ω7c) and summed feature 8 (comprising C18:1 ω6c and/or C18:1 ω7c). The 16S rRNA gene sequence similarity between strain A79T and Marinomonas pollencensis IVIA-Po-185T was 97.4%, the similarities with other type strains of the genus Marinomonas were 93.8-96.7%. Based on the results, Marinomonas vulgaris sp. nov. was proposed as a novel species. The type strain is A79T (= MCCC 1K05799T = KCTC 82519T = JCM 34473T).

Complete genome sequence of marine Roseobacter lineage member Monaibacterium sp. ALG8 with six plasmids isolated from seawater around brown algae.

Monaibacterium sp. ALG8 (=MCCC 1 K04733) was isolated from seawater around brown algae. The genome of Monaibacterium sp. ALG8 was sequenced, one circular 3,036,380 bp chromosome and six circular plasmids ranging from 12,229 to 151,263 bp were found after assembly. The results of genomic annotation showed that Monaibacterium sp. ALG8 lacks the ability to degrade alginate, indicating its ecological role may not be directly related to the degradation of brown algae. The comparison of genomic features in the plasmids showed that almost all of these plasmids, except pALG4, were horizontally recruited from donors, not ancestors. Based on predicted functions, the existence of plasmids may provide strain ALG8 with advantages including nitrate reduction, tolerance of osmotic stress via glycine betaine, resistance to heavy metal stress such as mercury and cobalt, degradation of benzoate metabolites such as p-cumate, transformation of the swim-or-stick lifestyle and improvement of the immune system with two CRISPR-Cas systems. This study provides evidence for the carbon metabolic patterns of Monaibacterium sp. ALG8 and predicts the functions and donors of six plasmids in this strain, broadening our understanding of the ecological roles of bacteria in the environment around brown algae and the functions and evolutionary patterns of plasmids in marine Roseobacter lineage members.