Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China.
School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China.
Front Cell Infect Microbiol. 2024 Nov 1;14:1482919. doi: 10.3389/fcimb.2024.1482919. eCollection 2024.
Aerobic respiration is the key driver of proliferation and infection. Our previous transcriptome results suggested that knockout downregulates a few genes involved in NADH and ATP synthesis in the aerobic respiratory pathway. In this study, non-targeted metabolomics results showed that the differential metabolites affected by knockout were associated with aerobic respiration. Further results suggested that the key products of aerobic respiration, NADH and ATP, were reduced upon deletion and were not dependent on the classical σ pathway. The two-component system response factor aerobic respiration control A (ArcA) is involved in regulating NADH and ATP levels. qRT-PCR demonstrated that DegS negatively regulates the transcription of the gene, which negatively regulates the expression of isocitrate dehydrogenase (ICDH), a key rate-limiting enzyme of the tricarboxylic acid cycle. NADH and ATP levels were partially restored with the knockout of the gene in the strain, while levels were partially restored with overexpression of ICDH in the strain. In a growth experiment, compared to the strain, the growth rates of and -overexpressed strains () were partially restored during the logarithmic growth period. Colonization of the intestines of suckling mice showed a significant reduction in the colonizing ability of the strain, similar colonizing ability of the strain and the wild-type strain, and a partial recovery of the colonizing ability of the + strain. Overall, these findings suggest that the DegS protease regulates the expression of ICDH through ArcA, thereby affecting the NADH and ATP levels of and its growth and intestinal colonization ability.
有氧呼吸是增殖和感染的关键驱动力。我们之前的转录组结果表明，敲除会下调有氧呼吸途径中参与 NADH 和 ATP 合成的少数基因。在这项研究中，非靶向代谢组学结果表明，敲除影响的差异代谢物与有氧呼吸有关。进一步的结果表明，有氧呼吸的关键产物 NADH 和 ATP 在 缺失时减少，并且不依赖于经典的 σ 途径。双组分系统响应因子有氧呼吸控制 A（ArcA）参与调节 NADH 和 ATP 水平。qRT-PCR 表明 DegS 负调控 基因的转录，该基因负调控三羧酸循环的关键限速酶异柠檬酸脱氢酶（ICDH）的表达。在 菌株中敲除 基因后，NADH 和 ATP 水平部分恢复，而在 菌株中过表达 ICDH 后水平部分恢复。在生长实验中，与 菌株相比，对数生长期 菌株和过表达 ICDH 的 菌株的生长速度部分恢复。在对哺乳期小鼠肠道的定植实验中， 菌株的定植能力显著降低， 菌株和野生型菌株的定植能力相似，而 +菌株的定植能力部分恢复。总体而言，这些发现表明 DegS 蛋白酶通过 ArcA 调节 ICDH 的表达，从而影响 和其生长和肠道定植能力的 NADH 和 ATP 水平。
