Journal of Microbiology

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Intestinibaculum porci gen. nov., sp. nov., a new member of the family Erysipelotrichaceae isolated from the small intestine of a swine: Ji-Sun Kim , Hanna Choe , Yu-Ri Lee , Kyung Mo Kim , Doo-Sang Park; J. Microbiol. 2019;57(5):381-387. Published online February 22, 2019; DOI: https://doi.org/10.1007/s12275-019-8631-8

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Abstract: A strictly anaerobic, Gram-stain-positive, catalase-negative, non-motile, rod-shaped bacterium, designated SG0102T, was isolated from the small intestine of a swine. Optimal growth occurred at 37°C and pH 7.0. Furthermore, growth was observed in the presence of up to 3% (w/v) NaCl but not at salinity levels higher than 4%. The comparative analysis of 16S rRNA gene sequences showed that strain SG0102T was most closely related to Kandleria vitulina DSM 20405T (93.3%), followed by Catenibacterium mitsuokai KCTC 5053T (91.1%), Sharpea azabuensis KCTC 15217T (91.0%), and Eggerthia catenaformis DSM 5348T (89.6%). The average nucleotide identity values between strain SG0102T and related species, K. vitulina DSM 20405T, C. mitsuokai KCTC 5053T, S. azabuensis KCTC 15217T, and E. catenaformis DSM 5348T, were 71.0, 69.3, 70.0, and 69.2%, respectively. The phylogenetic analysis based on 16S rRNA gene sequence revealed that strain SG0102T belonged to the family Erysipelotrichaceae in the class Erysipelotrichia. The DNA G+C content of the strain SG0102T was 39.5 mol%. The major cellular fatty acids (> 10%) of strain SG0102T were C16:0, C16:0 dimethyl acetal, and C18:2 ω9/12c. The cell wall peptidoglycan of strain SG0102T contained the meso-diaminopimelic acid. The strain SG0102T produced lactic acid as a major end product of fermentation. These distinct phenotypic and phylogenetic properties suggest that strain SG0102T represents a novel species in a novel genus of the family Erysipelotrichaceae, for which the name Intestinibaculum porci gen. nov. sp. nov. is proposed. The type strain is SG0102T (= KCTC 15725T = NBRC 113396T).

Effects of dietary poly-β-hydroxybutyrate (PHB) on microbiota composition and the mTOR signaling pathway in the intestines of Litopenaeus vannamei: Yafei Duan , Yue Zhang , Hongbiao Dong , Yun Wang , Jiasong Zhang; J. Microbiol. 2017;55(12):946-954. Published online December 7, 2017; DOI: https://doi.org/10.1007/s12275-017-7273-y

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Abstract: Poly-β-hydroxybutyrate (PHB) is a natural polymer of the short chain fatty acid β-hydroxybutyrate, which acts as a microbial control agent. The mammalian target of the rapamycin (mTOR) signaling pathway plays a crucial role in intestine inflammation and epithelial morphogenesis. In this study, we examined the composition of intestine microbiota, and mTOR signaling-related gene expression in Pacific white shrimp Litopenaeus vannamei fed diets containing different levels of PHB: 0% (Control), 1% (PHB1), 3% (PHB3), and 5% (PHB5) (w/w) for 35 days. High-throughput sequencing analysis revealed that dietary PHB altered the composition and diversity of intestine microbiota, and that the microbiota diversity decreased with the increasing doses of PHB. Specifically, dietary PHB increased the relative abundance of Proteobacteria and Tenericutes in the PHB1 and PHB5 groups, respectively, and increased that of Gammaproteobacteria in the three PHB groups. Alternatively, PHB decreased Alphaproteobacteria in the PHB3 and PHB5 groups. At the genus level, dietary PHB increased the abundance of beneficial bacteria, such as Bacillus, Lactobacillus, Lactococcus, Clostridium, and Bdellovibrio. The relative mRNA expression levels of the mTOR signaling-related genes TOR, 4E-BP, eIF4E1α, and eIF4E2 all increased in the three PHB treatment groups. These
results
revealed that dietary PHB supplementation had a beneficial effect on intestine health of L. vannamei by modulating the composition of intestine microbiota and activating mTOR signaling.

Research Support, Non-U.S. Gov't

Intestinal Intraepithelial TCRγδ+ T Cells are Activated by Normal Commensal Bacteria: Sang Phil Jeong , Jung-Ah Kang , Sung-Gyoo Park; J. Microbiol. 2012;50(5):837-841. Published online November 4, 2012; DOI: https://doi.org/10.1007/s12275-012-2468-8

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Abstract: TCRγδ+ T cells play a critical role in protecting the intestinal mucosa against pathogenic infection. In the absence of infection, TCRγδ+ T cell activation must be continuously regulated by T regulatory cells (Treg) to prevent the development of colitis. However, the activation of intestinal TCRγδ+ T cells under normal conditions has not been clearly resolved. In order to determine TCRγδ+ T cell activation in vivo, we designed an NF-κB based reporter system. Using the recombinant lentiviral method, we delivered the NF-κB reporter to isolated TCRγδ+ T cells, which were then adoptively transferred into normal mice. Our data indicate that the NF-κB activation level in TCRγδ+ T cells is higher in the intestinal intraepithelial layer than in the lamina propria region. In addition, the surface expression level of lymphocyte activation marker CD69 in TCRγδ+ T cells is also higher in the intestinal intraepithelial layer and this activation was reduced by Sulfatrim treatment which removes of commensal bacteria. Collectively, our data indicate that the TCRγδ+ T cell population attached to the intestinal lumen is constitutively activated even by normal commensal bacteria.

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