College of Food Science and Engineering, Northwest A&F University, Yangling, China; Laboratory of Quality and Safety Risk Assessment for Agro-Products, Ministry of Agriculture, Yangling, China; National Engineering Research Center of Agriculture Integration Test, Yangling, China.
College of Food Science and Engineering, Northwest A&F University, Yangling, China; Laboratory of Quality and Safety Risk Assessment for Agro-Products, Ministry of Agriculture, Yangling, China; National Engineering Research Center of Agriculture Integration Test, Yangling, China.
Int J Food Microbiol. 2021 Jan 16;337:108927. doi: 10.1016/j.ijfoodmicro.2020.108927. Epub 2020 Oct 24.
Salmonella enterica serovar Enteritidis (S. Enteritidis) presents an excellent capacity to survive in egg white, which is a hostile environment for bacterial growth. To reveal its survival mechanism, this study focuses on the specific gene SEN1393, which has been found to exist only in the genomic sequence of S. Enteritidis. The survival capacity of the deletion mutant strain ΔSEN1393 was proven to be significantly reduced after incubation in egg white. RNA sequencing and RT-qPCR results demonstrate that the expression levels of 19 genes were up-regulated, while the expression levels of 9 genes were down-regulated in egg white. These genes were classified into 6 groups based on their functional categories, namely the sulfate assimilation pathway, arginine biosynthesis, the tricarboxylic acid cycle, the fimbrial protein, the transport and chelation of metal ion, and others (sctT, rhs, and pspG). The strain ΔSEN1393 was deduced to damage FeS cluster enzymes and increase the sulfate and iron requirements, and to reduce bacterial motility and copper homeostasis. Via InterProScan analysis, the gene SEN1393 was speculated to encode a TerB-like and/or DjlA-like protein, and therefore, together with cysJ, possibly reduced the oxidative toxicities resulting from oxyanions such as tellurite, and/or improved CysPUWA conformation to restrain the uptake of the toxic oxyanions. In summary, the gene SEN1393 enabled the higher survival of S. Enteritidis in egg white as compared to other pathogens by regulating the sulfate assimilation pathway.
肠炎沙门氏菌血清型肠炎亚种（S. Enteritidis）在蛋清中具有出色的生存能力，蛋清是细菌生长的恶劣环境。为了揭示其生存机制，本研究集中于特定基因 SEN1393，该基因仅存在于 S. Enteritidis 的基因组序列中。经过在蛋清中孵育，ΔSEN1393 缺失突变株的生存能力被证明显著降低。RNA 测序和 RT-qPCR 结果表明，19 个基因的表达水平上调，而在蛋清中 9 个基因的表达水平下调。这些基因根据其功能类别分为 6 组，即硫酸盐同化途径、精氨酸生物合成、三羧酸循环、菌毛蛋白、金属离子的运输和螯合以及其他（sctT、rhs 和 pspG）。推断出菌株ΔSEN1393 破坏 FeS 簇酶并增加硫酸盐和铁的需求，降低细菌的运动性和铜的体内平衡。通过 InterProScan 分析，推测基因 SEN1393 编码 TerB 样和/或 DjlA 样蛋白，因此与 cysJ 一起，可能降低了碲酸盐等含氧阴离子的氧化毒性，和/或改善 CysPUWA 构象以抑制有毒含氧阴离子的摄取。综上所述，与其他病原体相比，SEN1393 基因使肠炎沙门氏菌在蛋清中具有更高的生存能力，通过调节硫酸盐同化途径。
