Role of protease maturation lipoprotein in osmoadaptation of Streptococcus mutans. Issue 1 (26th June 2014)

• Record Type: Journal Article
• Authors: Kunii, Maiko; Arimoto, Takafumi; Hasegawa, Tokuji; Kuwata, Hirotaka; Igarashi, Takeshi
• Is Part Of: FEMS microbiology letters. Volume 356:Issue 1(2014:Jul.)
• Page Start: 45
• Page End: 52
• Publication Date: 2014-06-26
• Subjects: Microbiology -- Periodicals; 579
• DOI: 10.1111/1574-6968.12477
• Languages: English
• ISSNs: 0378-1097

Abstract

<abstract abstract-type="main" id="fml12477-abs-0001"> <title>Abstract</title> <p>Osmoadaptation may be an important trait for the pathogenicity of <italic>Streptococcus mutans</italic>. However, how this organism adapts to changes in osmolality in the oral cavity remains unclear. In this study, we showed that <italic>S. mutans</italic> utilizes K<sup>+</sup> for osmoadaptation, in which protease maturation lipoprotein (PrtM) plays an important role. Although growth of the wild‐type strain was impaired in a hyperosmotic medium [brain heart infusion (BHI) containing 0.3 M NaCl] compared with that in an unmodified BHI, the <italic>prtM</italic> mutant grew much more poorly in 0.3 M NaCl BHI. Comparison of growth behavior in the hyperosmotic medium supplemented with different osmoprotectants revealed that only the addition of K<sup>+</sup> allowed the bacteria to overcome the impairment of growth caused by the high osmolality. These results suggest that K<sup>+</sup> is an important compatible solute for <italic>S. mutans</italic>. Moreover, K<sup>+</sup>‐associated recovery of growth was not observed for the <italic>prtM</italic> mutant, indicating that PrtM plays a critical role in the utilization of K<sup>+</sup>. Quantitative reverse‐transcriptase polymerase chain reaction analysis showed that <italic>prtM</italic> was induced by osmotic stress, implying that <italic>prtM</italic> is an osmoresponsive gene. These findings suggest that K<sup>+</sup> is an important compatible solute for <italic>S. mutans</italic>, and that the osmoresponsive lipoprotein PrtM is involved in K<sup>+</sup> utilization, contributing to osmoadaptation of <italic>S. mutans</italic>.</p> </abstract>