弯曲广布乳杆菌 HFS9 基因组分析及益生特性

Genomic characteristics and probiotic properties of Latilactobacillus curvatus HFS9

摘要:

【背景】近年来，弯曲广布乳杆菌的健康益处受到广泛关注；基因组分析结合表型实验的方法为益生菌开发提供了新思路。【目的】探索分离自健康人粪便的弯曲广布乳杆菌HFS9基因组特征及益生潜力。【方法】通过泛基因组分析对弯曲广布乳杆菌基因组特征进行描述，基于功能数据库注释并分析HFS9益生相关基因；通过耐酸耐胆盐实验、自聚集、疏水性和细胞黏附实验、抗生素敏感性试验、自由基清除实验及抑菌试验等对HFS9的体外益生特性进行评估；构建小鼠结肠炎模型初步评估HFS9的体内抗炎作用。【结果】弯曲广布乳杆菌具有开放的泛基因组和保守的核心基因组。HFS9基因组大小为1.97 Mb，GC含量为41.86%，蛋白质编码区数目为2 050个；含乳杆菌噬菌体PLE3编码基因及与细胞黏附、酸耐受、胆盐耐受和抗氧化等相关的益生基因。HFS9在酸和胆盐环境中的存活率分别为62.42%和92.92%；自聚集能力和疏水性分别为63.33%和75.00%，对人结肠癌细胞(HT-29细胞)的黏附率为12.97%；对选用的大多数抗生素敏感；对6种常见人体致病菌均具有抑制作用；具有清除1,1-二苯基-2-三硝基苯肼[1,1-diphenyl-2-picrylhydrazyl radical 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl, DPPH]自由基和羟自由基的能力。此外，HFS9可缓解实验性小鼠结肠炎症状，改善结肠缩短和组织病理学变化。【结论】弯曲广布乳杆菌HFS9含有益生相关基因且具有体内外益生特性，可作为益生菌候选菌株进一步开发利用。

关键词:弯曲广布乳杆菌;泛基因组;核心基因组;益生基因;益生菌

Abstract:

[Background] In recent years, the health benefits of Latilactobacillus curvatus have received much attention and genome analysis combined with phenotypic test provides a new approach for the development of probiotics. [Objective] To explore the genomic characteristics and probiotic properties of L. curvatus HFS9 isolated from healthy human feces. [Methods] The genome of L. curvatus HFS9 was characterized by pan-genome analysis and genomic annotation was performed to identify the probiotic genes. The probiotic properties of L. curvatus HFS9 in vitro were assessed based on survivability in low pH and 0.3% bile salt, self-aggregation capacity, hydrophobicity and cell adhesion, susceptibility tests, radical scavenging activities, and antibacterial experiments. The mouse model of colitis was established to evaluate the anti-inflammatory effect of HFS9 in vivo. [Results] L. curvatus had an open pan-genome and a conserved core genome. The genome of L. curvatus HFS9 was 1.97 Mb, with the GC content of 41.86% and 2 050 coding sequences. It carried Lactobacillus phage PLE3 genes and possessed the probiotic genes related to cell adhesion, acid tolerance, bile salt tolerance, and antioxidation. The survival rates of L. curvatus HFS9 in acid and bile salt environments were 62.42% and 92.92%, respectively. The self-aggregation capacity and hydrophobicity of L. curvatus HFS9 were 63.33% and 75.00%, respectively. L. curvatus HFS9 showed the adhesion rate of 12.97% to human colon cancer cells (HT-29 cells), was sensitive to most of the antibiotics tested, had inhibitory effects on six common human pathogens, and possessed the abilities to scavenge 1,1-diphenyl-2-picrylhydrazyl radical 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH) and hydroxyl radicals. In addition, L. curvatus HFS9 relieved the symptoms and ameliorated colon shortening and histopathological changes in the mouse model of colitis. [Conclusion] L. curvatus HFS9 contains probiotic genes and has probiotic properties in vitro and in vivo, which can be further developed and utilized as a candidate probiotic strain.

Key words:Latilactobacillus curvatus;pan-genome;core genome;probiotic genes;probiotics