一氧化氮(NO)是一种反应性氮(RNS),在调节炎症过程中起着至关重要的作用。在异常情况下,过量的NO水平可以促进细胞成分的氧化,可能导致或加剧高血压等疾病,心血管功能障碍,和炎症性肠病(IBD)。先前的研究表明,降低管腔中的NO水平可以减轻IBD的临床症状。因此,我们的目的是鉴定可以减少RNS并可用作有价值的益生菌的细菌。在这项研究中,我们从人类粪便中分离出抗亚硝酸盐胁迫的细菌,并使用16S和全基因组测序将其鉴定为植物乳杆菌LP7(LP7)。LP7菌株在高亚硝酸盐水平下存活和减少亚硝酸盐的能力比参考菌株植物乳杆菌ATCC14917(ATCC14917)更大。为了更详细地表征LP7基因组,我们进行了比较基因组分析.然而,LP7基因组中不存在直接赋予抵抗亚硝酸盐胁迫能力的独特基因。此外,我们对用亚硝酸盐处理的LP7和ATCC14917细胞进行了转录组学分析.我们发现,参与细胞分裂过程的基因的表达水平在LP7中被诱导,其显示出比ATCC14917更规则的杆状。这可以解释为什么LP7在亚硝酸盐胁迫下比ATCC14917更好地存活。基于其在亚硝酸盐胁迫下更好地存活和降低亚硝酸盐浓度的能力,我们认为LP7可能是一种有价值的益生菌菌株。
Nitric oxide (NO) is a reactive nitrogen species (RNS) that plays a vital role in regulating inflammatory processes. Under abnormal conditions, excessive NO levels can promote the oxidation of cellular components, which may cause or exacerbate diseases such as hypertension, cardiovascular dysfunction, and inflammatory bowel disease (IBD). Previous studies have shown that reducing NO levels in the lumen can attenuate the clinical symptoms of IBD. Thus, we aimed to identify bacteria that can reduce RNS and that can be used as valuable probiotics. In this study, we isolated bacteria resistant to nitrite stress from human feces and used 16S and whole-genome sequencing to identify them as Lactiplantibacillus plantarum LP7 (LP7). The ability to survive at high nitrite levels and to decrease them was greater in the LP7 strain than in the reference strain L. plantarum ATCC14917 (ATCC14917). To characterize the LP7 genome in more detail, we performed a comparative genome analysis. However, the unique genes that directly confer the ability to withstand nitrite stress were not present in the LP7 genome. Furthermore, we performed transcriptomic analysis of LP7 and ATCC14917 cells treated with nitrite. We found that the expression levels of genes involved in the cell division process were induced in LP7, which showed a more regular rod-shape than ATCC14917. This could explain why LP7 can survive better than ATCC14917 under nitrite stress. Based on its ability to survive better in nitrite stress and decrease nitrite concentration, we suggest that LP7 could be a valuable probiotic strain.