Yu Seung Yeob, Oh Byeong Seob, Ryu Seoung Woo, Bak Jeong Eun, Heo Eun Seo, Moon Jeong Chan, Jeong Jae-Ho, Lee Ju Huck
Korean Collection for Type Cultures, Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup, Republic of Korea.
BioMedical Sciences Graduate Program (BMSGP), Chonnam National University, Hwasun, Republic of Korea.
Front Microbiol. 2024 Apr 2;15:1342098. doi: 10.3389/fmicb.2024.1342098. eCollection 2024.
A novel Gram-negative, obligate anaerobe, non-motile, flagella-lacking, catalase- and oxidase-negative, coccobacilli-shaped bacterial strain designated AGMB02718 was isolated from swine feces. The 16S rRNA gene analysis indicated that strain AGMB02718 belonged to the genus with the highest similarity to 4NBBH2 (= DSM 106860) (sequence similarity of 96.2%), forming a distinct phylogenetic lineage. Its growth occurred at 25-45°C (optimal 37°C) and in 0.5-1% NaCl (optimal 0.5%). Strain AGMB02718 was asaccharolytic and contained menaquinone 6 (MK-6) and methylmenaquinone 6 (MMK-6) as the predominant respiratory quinones. The major cellular fatty acids in the isolate were C9 and C. Based on the whole-genome sequencing analysis, strain AGMB02718 had a 2,606,253 bp circular chromosome with a G + C content of 62.2%. The average nucleotide identity value between strain AGMB02718 and 4NBBH2 was 72.1%, while the digital DNA-DNA hybridization value was 20.9%. Interestingly, genome analysis suggested that strain AGMB02718 possessed a low-toxicity lipopolysaccharide (LPS) because the genome of the isolate does not include and genes for Kdo-Lipid A (KLA) assembly, which confers high toxicity to LPS. Moreover, macrophage stimulation assay confirmed that AGMB02718 produced LPS with low toxicity. Because the low-toxicity LPS produced by the family is involved in regulating host immunity and low-toxicity LPS-producing strains can help maintain host immune homeostasis, we evaluated the anti-inflammatory activity of strain AGMB02718 against inflammatory bowel disease (IBD). As a result, strain AGMB02718 was able to prevent the inflammatory response in a dextran sulfate sodium (DSS)-induced colitis model. Therefore, this strain represents a novel species of that has a protective effect against DSS-induced colitis, and the proposed name is sp. nov. The type strain is AGMB02718 (=GDMCC 1.2717 = KCTC 25541).
从猪粪便中分离出一株新型革兰氏阴性、专性厌氧、不运动、无鞭毛、过氧化氢酶和氧化酶阴性、球杆菌形的细菌菌株，命名为AGMB02718。16S rRNA基因分析表明，AGMB02718菌株属于该属，与4NBBH2（=DSM 106860）相似度最高（序列相似度为96.2%），形成一个独特的系统发育谱系。其生长温度为25-45°C（最适温度37°C），NaCl浓度为0.5-1%（最适浓度0.5%）。AGMB02718菌株不能分解糖类，主要呼吸醌为甲基萘醌6（MK-6）和甲基萘醌6（MMK-6）。该分离株的主要细胞脂肪酸为C9和C。基于全基因组测序分析，AGMB02718菌株有一条2,606,253 bp的环状染色体，G+C含量为62.2%。AGMB02718菌株与4NBBH2的平均核苷酸同一性值为72.1%，数字DNA-DNA杂交值为20.9%。有趣的是，基因组分析表明，AGMB02718菌株具有低毒性脂多糖（LPS），因为该分离株的基因组不包括参与Kdo-脂质A（KLA）组装的基因，而KLA会赋予LPS高毒性。此外，巨噬细胞刺激试验证实AGMB02718产生的LPS毒性较低。由于该科产生的低毒性LPS参与调节宿主免疫，且产生低毒性LPS的菌株有助于维持宿主免疫稳态，我们评估了AGMB02718菌株对炎症性肠病（IBD）的抗炎活性。结果，AGMB02718菌株能够在葡聚糖硫酸钠（DSS）诱导的结肠炎模型中预防炎症反应。因此，该菌株代表了一种对DSS诱导的结肠炎具有保护作用的新物种，提议的名称为新种。模式菌株为AGMB02718（=GDMCC 1.2717 = KCTC 25541）。
