Zhao Lei, Zhang Yinan, Liu Yang, Zhong Jiang, Zhang Dong
Key Laboratory of Milk and Dairy Products Detection and Monitoring Technology for State Market Regulation, Shanghai Institute of Quality Inspection and Technical Research, Shanghai 200233, China.
State Key Laboratory of Genetic Engineering, Department of Microbiology and Immunology, School of Life Sciences, Fudan University, Shanghai 200438, China.
Microorganisms. 2023 Jan 5;11(1):140. doi: 10.3390/microorganisms11010140.
is a generalist that can adapt to different ecological niches, serving as a valuable source of probiotics. The genome of X253 contains one chromosome and no plasmids, with a size of 2.99 Mb. Both single-copy orthologous gene-based phylogenetic analysis and average nucleotide identity indicated that dairy-derived X253 was most closely related to the human-intestine-derived strain LOCK908, rather than other dairy strains. The adaptation of X253 and the human-intestine-derived strain GG to different ecological niches was explained by structural variation analysis and COG annotation. Hemolytic assays, API ZYM assays, and antimicrobial susceptibility tests were performed to validate risk-related sequences such as virulence factors, toxin-encoding genes, and antibiotic-resistance genes in the genomes of X253 and GG. The results showed that GG was able to use L-fucose, had a higher tolerance to bile salt, and adhered better to CaCo-2 cells. In contrast, X253 was capable of utilizing D-lactose, withstood larger quantities of hydrogen peroxide, and possessed excellent antioxidant properties. This study confirmed the safety and probiotic properties of X253 via complete genome and phenotype analysis, suggesting its potential as a probiotic.
是一种能够适应不同生态位的泛养菌，可作为益生菌的宝贵来源。X253的基因组包含一条染色体且无质粒，大小为2.99 Mb。基于单拷贝直系同源基因的系统发育分析和平均核苷酸同一性均表明，源自乳制品的X253与源自人类肠道的菌株LOCK908关系最为密切，而非其他乳制品菌株。通过结构变异分析和COG注释解释了X253和源自人类肠道的菌株GG对不同生态位的适应性。进行了溶血试验、API ZYM试验和抗菌药敏试验，以验证X253和GG基因组中与风险相关的序列，如毒力因子、毒素编码基因和抗生素抗性基因。结果表明，GG能够利用L-岩藻糖，对胆盐具有更高的耐受性，并且对CaCo-2细胞的黏附性更好。相比之下，X253能够利用D-乳糖，耐受大量过氧化氢，并具有出色的抗氧化性能。本研究通过全基因组和表型分析证实了X253的安全性和益生菌特性，表明其作为益生菌的潜力。
