Manganese Uptake, Mediated by SloABC and MntH, Is Essential for the Fitness of Streptococcus mutans.

摘要: ABSTRACT Early epidemiological studies implicated manganese (Mn) as a possible caries-promoting agent, while laboratory have indicated that stimulates the expression of virulence-related factors in dental pathogen Streptococcus mutans. To better understand importance homeostasis to S. mutans pathophysiology, we first used RNA sequencing obtain global transcriptional profile UA159 grown under Mn-restricted conditions. Among most highly expressed genes were those entire sloABC operon, encoding dual iron/manganese transporter, and an uncharacterized gene, here mntH, codes for protein bearing strong similarity Nramp-type transporters. While inactivation sloC, which encodes lipoprotein receptor SloABC system, or mntH alone had no major consequence overall fitness mutans, simultaneous sloC (ΔsloC ΔmntH) impaired growth survival conditions, including human saliva presence calprotectin. Further, disruption Mn transport resulted diminished stress tolerance reduced biofilm formation sucrose. These phenotypes markedly improved when cells provided with excess Mn. Metal quantifications revealed single mutant strains contained intracellular levels similar seen parent strain, whereas was nearly undetectable ΔsloC ΔmntH strain. Collectively, these results reveal MntH work independently cooperatively promote cell conditions maintenance is essential virulence attributes IMPORTANCE As transition biometals such are all forms life, ability scavenge metal-restricted host environment important trait successful cariogenic pathobionts. Here, showed caries utilizes two systems, namely, MntH, acquire from maintain cellular manifestation characteristics associate caries. Our indicate development strategies deprive hold promise combat against this bacterial pathogen.