Zeng Lin, Noeparvar Payam, Burne Robert A, Glezer Benjamin S
Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA.
J Oral Microbiol. 2024 Mar 3;16(1):2322241. doi: 10.1080/20002297.2024.2322241. eCollection 2024.
To analyze contributions to microbial ecology of Reactive Electrophile Species (RES), including methylglyoxal, generated during glycolysis.
Genetic analyses were performed on the glyoxalase pathway in Streptococcus mutans (SM) and Streptococcus sanguinis (SS), followed by phenotypic assays and transcription analysis.
Deleting glyoxalase I (lguL) reduced RES tolerance to a far greater extent in SM than in SS, decreasing the competitiveness of SM against SS. Although SM displays a greater RES tolerance than SS, lguL-null mutants of either species showed similar tolerance; a finding consistent with the ability of methylglyoxal to induce the expression of lguL in SM, but not in SS. A novel paralogue of lguL (named gloA2) was identified in most streptococci. SM mutant ∆gloA2SM showed little change in methylglyoxal tolerance yet a significant growth defect and increased autolysis on fructose, a phenotype reversed by the addition of glutathione, or by the deletion of a fructose: phosphotransferase system (PTS) that generates fructose-1-phosphate (F-1-P).
Fructose contributes to RES generation in a PTS-specific manner, and GloA2 may be required to degrade certain RES derived from F-1-P. This study reveals the critical roles of RES in fitness and interbacterial competition and the effects of PTS in modulating RES metabolism.
分析糖酵解过程中产生的包括甲基乙二醛在内的活性亲电物质（RES）对微生物生态学的影响。
对变形链球菌（SM）和血链球菌（SS）中的乙二醛酶途径进行遗传分析，随后进行表型分析和转录分析。
缺失乙二醛酶I（lguL）后，SM对RES的耐受性下降程度远大于SS，降低了SM与SS竞争的能力。尽管SM比SS表现出更高的RES耐受性，但两种菌的lguL基因缺失突变体表现出相似的耐受性；这一发现与甲基乙二醛能够诱导SM中lguL的表达，但不能诱导SS中lguL的表达这一现象一致。在大多数链球菌中鉴定出一种新的lguL旁系同源物（命名为gloA2）。SM突变体∆gloA2SM在甲基乙二醛耐受性方面变化不大，但在果糖上出现明显的生长缺陷和自溶增加，添加谷胱甘肽或缺失产生果糖-1-磷酸（F-1-P）的果糖：磷酸转移酶系统（PTS）可逆转该表型。
果糖以PTS特异性方式促进RES的产生，可能需要GloA2来降解某些源自F-1-P的RES。本研究揭示了RES在适应性和细菌间竞争中的关键作用以及PTS对RES代谢的调节作用。
