Effects of Arginine on Streptococcus mutans Growth, Virulence Gene Expression, and Stress Tolerance
Effects of Arginine on Streptococcus mutans Growth, Virulence Gene Expression, and Stress Tolerance
复制标题
DOI：
10.1128/aem.00496-17
复制
发表时间：
2017-08-01
影响因子：
4.4
通讯作者：
Burne, Robert A.
中科院分区：
文献类型：
--
作者：
Chakraborty, Brinta;Burne, Robert A.
变形链球菌是口腔生物膜的常见成分，也是人类龋病的主要病原体。与龋齿相关的细菌具有从膳食碳水化合物产生有机酸并在酸性条件下生长和代谢的强大能力。相比之下，许多口腔细菌通过精氨酸脱亚胺酶系统（ADS）产生氨，其调节口腔生物膜的pH。ADS的精氨酸代谢对龋齿的发生和发展具有重要的抑制作用。本研究观察了外源L-精氨酸对沙门氏菌生长、毒力和环境胁迫耐受性的影响。变种人添加终浓度为1.5%的精氨酸对S.在复杂和化学成分确定的培养基中，特别是当细胞暴露于酸或氧化应激时，编码附着/积累所需的毒力因子（gtfB和spaP）、细菌素（nlmA、nlmB、nlmD和cipB）和感受态发育所需的σ因子（comX）的基因在1.5%精氨酸的生长期间下调。RNA的深度测序（RNA-Seq）比较了S.在含有和不含1.5%精氨酸的化学成分确定的培养基中生长的变异株揭示了编码ATP结合盒转运蛋白、金属转运蛋白和生存、代谢和生物膜形成所需的成分的基因的差异表达。因此，精氨酸抑制龋齿的作用机制包括对最常见的人类龋齿病原体的多种毒性相关性质的直接不利影响。重要性某些口腔细菌的精氨酸脱亚胺酶系统（ADS）对氨基酸精氨酸的代谢提高了牙菌斑的pH，并为健康相关细菌提供了选择性优势，从而保护宿主免于龋齿（蛀牙）。在这里，我们研究了精氨酸对引起蛀牙的细菌变形链球菌的影响。我们发现精氨酸对生长、致病潜力和环境胁迫耐受性产生负面影响，这种影响可能会损害S.变异体导致疾病。利用遗传学和基因组学技术，探讨精氨酸对S.变种人被发现了本报告表明，精氨酸抑制龋齿发生和发展的主要作用机制可能是通过降低S.变种人
Streptococcus mutans is a common constituent of oral biofilms and a primary etiologic agent of human dental caries. The bacteria associated with dental caries have potent abilities to produce organic acids from dietary carbohydrates and to grow and metabolize in acidic conditions. By contrast, many commensal bacteria produce ammonia through the arginine deiminase system (ADS), which moderates the pH of oral biofilms. Arginine metabolism by the ADS is a significant deterrent to the initiation and progression of dental caries. In this study, we observed how exogenously provided L-arginine affects the growth, the virulence properties, and the tolerance of environmental stresses of S. mutans. Supplementation with 1.5% arginine (final concentration) had an inhibitory effect on the growth of S. mutans in complex and chemically defined media, particularly when cells were exposed to acid or oxidative stress. The genes encoding virulence factors required for attachment/accumulation (gtfB and spaP), bacteriocins (nlmA, nlmB, nlmD, and cipB), and the sigma factor required for competence development (comX) were downregulated during growth with 1.5% arginine. Deep sequencing of RNA (RNA-Seq) comparing the transcriptomes of S. mutans growing in chemically defined media with and without 1.5% arginine revealed differential expression of genes encoding ATP-binding cassette transporters, metal transporters, and constituents required for survival, metabolism, and biofilm formation. Therefore, the mechanisms of action by which arginine inhibits dental caries include direct adverse effects on multiple virulence-related properties of the most common human dental caries pathogen.IMPORTANCE Metabolism of the amino acid arginine by the arginine deiminase system (ADS) of certain oral bacteria raises the pH of dental plaque and provides a selective advantage to health-associated bacteria, thereby protecting the host from dental caries (cavities). Here, we examine the effects of arginine on the cavity-causing bacterium Streptococcus mutans. We find that arginine negatively impacts the growth, the pathogenic potential, and the tolerance of environmental stresses in a way that is likely to compromise the ability of S. mutans to cause disease. Using genetic and genomic techniques, multiple mechanisms by which arginine exerts its influence on virulence-related properties of S. mutans are discovered. This report demonstrates that a primary mechanism of action by which arginine inhibits the initiation and progression of dental caries may be by reducing the pathogenic potential of S. mutans.