Recent RNA sequencing studies have given us a deeper insight into the cariogenic impact of carbohydrate sources in the bacterium Streptococcus mutans, the principal microbial agent in dental caries etiopathogenesis. The process of dental caries development is facilitated by the ability of this bacterium to ferment some carbohydrates into organic acids contributing to a pH decrease in the oral cavity and the demineralization of the hard tissues of the tooth. Furthermore, in dental caries progression, biofilm formation, which starts and ends with free planktonic cells, plays an important role and has several unique properties called virulence factors. The most cariogenic carbohydrate is sucrose, an easily metabolizable source of energy that induces the acidification and synthesis of glucans, forming typical bacterial cell clumps. We used multifaceted methodological approaches to compare the transcriptomic and metabolomic profiles of S. mutans growing in planktonic culture on preferred and nonpreferred carbohydrates and in fasting conditions. Streptococcus mutans in a planktonic culture with lactose produced the same pH drop as glucose and sucrose. By contrast, xylitol and lactose showed high effectiveness in regulating intracellular polysaccharide metabolism, cell wall structure, and overall virulence involved in the initial phase of biofilm formation and structure but with an opposite pattern compared with sucrose and glucose. Our results confirmed the recent findings that xylitol and lactose play a vital role in biofilm structure. However, they do not reduce its formation, which is related to the creation of a cariogenic environment.

中文翻译：

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暴露于膳食碳水化合物葡萄糖、蔗糖、乳糖和木糖醇期间变形链球菌的基因表达和代谢活性

最近的 RNA 测序研究使我们更深入地了解了变形链球菌（龋齿发病机制中的主要微生物）中碳水化合物来源的致龋影响。这种细菌能够将一些碳水化合物发酵成有机酸，从而导致口腔 pH 值降低和牙齿硬组织脱矿质，从而促进了龋齿的发展过程。此外，在龋齿进展中，以游离浮游细胞开始和结束的生物膜形成发挥着重要作用，并具有多种称为毒力因子的独特特性。最致龋的碳水化合物是蔗糖，它是一种易于代谢的能量来源，可诱导葡聚糖的酸化和合成，形成典型的细菌细胞团块。我们使用多方面的方法学方法来比较在首选和非首选碳水化合物以及禁食条件下浮游培养中生长的变形链球菌的转录组学和代谢组学特征。含有乳糖的浮游培养物中的变形链球菌产生与葡萄糖和蔗糖相同的 pH 值下降。相比之下，木糖醇和乳糖在调节细胞内多糖代谢、细胞壁结构和生物膜形成和结构初始阶段涉及的整体毒力方面表现出高效，但与蔗糖和葡萄糖相比具有相反的模式。我们的结果证实了最近的发现，即木糖醇和乳糖在生物膜结构中发挥着至关重要的作用。然而，它们并没有减少其形成，这与致龋环境的形成有关。