Kocuria subflava sp. nov., isolated from marine sediment from the Indian Ocean

Draft Genome Sequences of the Kocuria subflava Type Strain KCTC 39547 and Kocuria sp. Strain JC486, a Newly Isolated Strain from a Wild Ass Sanctuary in Gujarat, India

Here, we report a 2.86-Mbp genome sequence of Kocuria sp. strain JC486, which was isolated from a salt marsh, and a 3.03-Mbp sequence of the type strain Kocuria subflava KCTC 39547. Prediction from their genomes indicates that both strains are nonpathogenic.

Separation and identification of diacylglycerols containing branched chain fatty acids by liquid chromatography-mass spectrometry

A combination of two chromatographic and two enzymatic methods was used for the analysis of molecular species of lipids from Gram-positive bacteria of the genus Kocuria. Gram-positive bacteria contain a majority of branched fatty acids (FAs), especially iso- and/or anteiso-FAs. Two strains K. rhizophila were cultivated at three different temperatures (20, 28, and 37°C) and the majority phospholipid, i.e., the mixture of molecular species of phosphatidylglycerols (PGs) was separated by means of hydrophilic interaction liquid chromatography (HILIC). After enzymatic hydrolysis of PGs by phospholipase C and derivatization of the free OH group, the sn-1,2-diacyl-3-acetyl triacylglycerols (AcTAGs) were separated by reversed phase HPLC. Molecular species such as i-15:0/i-15:0/2:0, ai-15:0/ai-15:0/2:0, and 15:0/15:0/2:0 (straight chains) were identified by liquid chromatography-positive electrospray ionization mass spectrometry. The tandem mass spectra of both standards and natural compounds containing iso, anteiso and straight chain FAs with the same carbons were identical. Therefore, for identification of the ratio of two regioisomers, i.e. i-15:0/ai-15:0/2:0 vs. ai-15:0/i-15:0/2:0, they were cleavage by pancreatic lipase. The mixture of free fatty acids (FFAs) and 2-monoacylglycerols (2-MAGs) was obtained. After their separation by TLC and esterification and/or transesterification, the fatty acid methyl esters were quantified by GC-MS and thus the ratio of regioisomers was determined. It has been shown that the ratio of PG (containing as majority i-15: 0 / i-15: 0, i-15: 0 / ai-15: 0 and / or ai-15: 0 / i-15: 0 and ai-15: 0 / ai-15: 0 molecular species) significantly affected the membrane flow of bacterial cells cultured at different temperatures.

Kocuria coralli sp. nov., a novel actinobacterium isolated from coral reef seawater

An actinobacterial strain, SCSIO 13007^T, was isolated from seawater collected from the Luhuitou fringing reef at a depth of 4.2 m. Phylogenetic and phenotypic properties of the organism supported the hypothesis that it represented a member of the genus Kocuria. Phylogenetic analysis indicated that the levels of 16S rRNA gene sequence similarity between SCSIO 13007^T and type strains of other recognized members of the genus Kocuria were lower than 96.99 %. Growth in the presence of up to 15 % (w/v) NaCl was a distinctive characteristic of SCSIO 13007^T. Other biochemical and physiological properties and the major fatty acids also differentiated the isolate from its phylogenetically closest relative Kocuria subflava YIM 13062^T. The menaquinone types were MK-7(H₂) and MK-8(H₂). Major cellular fatty acids were anteiso-C_15 : 0, iso-C_15 : 0 and anteiso-C_17 : 0. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, an unidentified lipid and an unidentified aminolipid. The DNA G+C content was 73.7 mol%. The combined genotypic and phenotypic data indicated that strain SCSIO 13007^T represents a novel species of the genus Kocuria, for which the name Kocuria coralli sp. nov. is proposed; the type strain is SCSIO 13007^T (=DSM 27811^T=NBRC 109942^T).

Marine Rare Actinomycetes: A Promising Source of Structurally Diverse and Unique Novel Natural Products

Rare actinomycetes are prolific in the marine environment; however, knowledge about their diversity, distribution and biochemistry is limited. Marine rare actinomycetes represent a rather untapped source of chemically diverse secondary metabolites and novel bioactive compounds. In this review, we aim to summarize the present knowledge on the isolation, diversity, distribution and natural product discovery of marine rare actinomycetes reported from mid-2013 to 2017. A total of 97 new species, representing 9 novel genera and belonging to 27 families of marine rare actinomycetes have been reported, with the highest numbers of novel isolates from the families Pseudonocardiaceae, Demequinaceae, Micromonosporaceae and Nocardioidaceae. Additionally, this study reviewed 167 new bioactive compounds produced by 58 different rare actinomycete species representing 24 genera. Most of the compounds produced by the marine rare actinomycetes present antibacterial, antifungal, antiparasitic, anticancer or antimalarial activities. The highest numbers of natural products were derived from the genera Nocardiopsis, Micromonospora, Salinispora and Pseudonocardia. Members of the genus Micromonospora were revealed to be the richest source of chemically diverse and unique bioactive natural products.

Comparative Genomics Provides Insights Into the Marine Adaptation in Sponge-Derived Kocuriaflava S43

Sponge-derived actinomycetes represent a significant component of marine actinomycetes. Members of the genus Kocuria are distributed in various habitats such as soil, rhizosphere, clinical specimens, marine sediments, and sponges, however, to date, little is known about the mechanism of their environmental adaptation. Kocuria flava S43 was isolated from a coastal sponge. Phylogenetic analysis revealed that it was closely related to the terrestrial airborne K. flava HO-9041. In this study, to gain insights into the marine adaptation in K. flava S43 we sequenced the draft genome for K. flava S43 by third generation sequencing (TGS) and compared it with those of K. flava HO-9041 and some other Kocuria relatives. Comparative genomics and phylogenetic analyses revealed that K. flava S43 might adapt to the marine environment mainly by increasing the number of the genes linked to potassium homeostasis, resistance to heavy metals and phosphate metabolism, and acquiring the genes associated with electron transport and the genes encoding ATP-binding cassette (ABC) transporter, aquaporin, and thiol/disulfide interchange protein. Notably, gene acquisition was probably a primary mechanism of environmental adaptation in K. flava S43. Furthermore, this study also indicated that the Kocuria isolates from various marine and hyperosmotic environments possessed common genetic basis for environmental adaptation.