Microbial niches in raw ingredients determine microbial community assembly during kimchi fermentation.

Fermented foods constitute hubs of microbial consortia differentially affecting nutritional and organoleptic properties, quality, and safety. Here we show the origin source of fermentative microbes and fermentation dynamics of kimchi. We partitioned microbiota by raw ingredient (kimchi cabbage, garlic, ginger, and red pepper) to render kimchi fermented by each source-originated microbe pool and applied multi-omics (metataxonomics and metabolomics), bacterial viability, and physiochemical analyses to longitudinally collected samples. Only kimchi cabbage- and garlic-derived microbial inoculums yielded successful kimchi fermentations. The dominant fermentative microbial taxa and subsequent metabolic outputs differed by raw ingredient type: the genus Leuconostoc, Weissella, and Lactobacillus for all non-sterilized ingredients, garlic, and kimchi cabbage, respectively. Gnotobiotic kimchi inoculated by mono-, di-, and tri- isolated fermentative microbe combinations further revealed W. koreensis-mediated reversible microbial metabolic outputs. The results suggest that the raw ingredient microbial habitat niches selectively affect microbial community assembly patterns and processes during kimchi fermentation.

The green tea modulates large intestinal microbiome and exo/endogenous metabolome altered through chronic UVB-exposure.

The attenuating effects of green tea supplements (GTS) against the ultraviolet (UV) radiation induced skin damages are distinguished. However, the concomitant effects of GTS on the large intestinal microbiomes and associated metabolomes are largely unclear. Herein, we performed an integrated microbiome-metabolome analysis to uncover the esoteric links between gut microbiome and exo/endogenous metabolome maneuvered in the large intestine of UVB-exposed mice subjected to dietary GTS. In UVB-exposed mice groups (UVB), class Bacilli and order Bifidobacteriales were observed as discriminant taxa with decreased lysophospholipid levels compared to the unexposed mice groups subjected to normal diet (NOR). Conversely, in GTS fed UVB-exposed mice (U+GTS), the gut-microbiome diversity was greatly enhanced with enrichment in the classes, Clostridia and Erysipelotrichia, as well as genera, Allobaculum and Lachnoclostridium. Additionally, the gut endogenous metabolomes changed with an increase in amino acids, fatty acids, lipids, and bile acids contents coupled with a decrease in nucleobases and carbohydrate levels. The altered metabolomes exhibited high correlations with GTS enriched intestinal microflora. Intriguingly, the various conjugates of green tea catechins viz., sulfated, glucuronided, and methylated ones including their exogenous derivatives were detected from large intestinal contents and liver samples. Hence, we conjecture that the metabolic conversions for the molecular components in GTS strongly influenced the gut micro-environment in UVB-exposed mice groups, ergo modulate their gut-microbiome as well as exo/endogenous metabolomes.

Nocardioides panacisoli sp. nov., isolated from the soil of a ginseng field.

A Gram-positive, rod-shaped, non-spore-forming bacterium (Gsoil 346(T)) was isolated from the soil of a ginseng field in South Korea and was characterized in order to determine its taxonomic position. On the basis of 16S rRNA gene sequences, strain Gsoil 346(T) was shown to belong to the genus Nocardioides in the family Nocardioidaceae, with the most closely related species being Nocardioides aquiterrae GW-9(T) (96.6 % 16S rRNA gene sequence similarity); however, the strain clustered in a distinct branch of the phylogenetic tree with Nocardioides kongjuensis A2-4(T) (96.2 %), Nocardioides aromaticivorans H-1(T) (96.1 %), Nocardioides nitrophenolicus NSP41(T) (96.1 %) and Nocardioides simplex ATCC 15799(T) (95.9 %). Strain Gsoil 346(T) was characterized chemotaxonomically and found to have ll-2,6-diaminopimelic acid in the cell-wall peptidoglycan, phosphatidylinositol and phosphatidylglycerol as the major polar lipids, MK-8(H(4)) as the predominant menaquinone and iso-C(16 : 0), C(18 : 1)omega9c and C(17 : 1)omega8c as the major fatty acids. The G+C content of the genomic DNA of the novel strain was 73.0 mol%. These chemotaxonomic properties supported the placement of strain Gsoil 346(T) in the genus Nocardioides. The results of physiological and biochemical tests, along with the phylogenetic analysis, allowed strain Gsoil 346(T) to be differentiated genotypically and phenotypically from recognized species of the genus Nocardioides. Therefore, strain Gsoil 346(T) represents a novel species, for which the name Nocardioides panacisoli sp. nov. is proposed, with Gsoil 346(T) (=KCTC 19470(T)=DSM 21348(T)) as the type strain.