Dataset Information

Novel Two-Component System of Streptococcus sanguinis Affecting Functions Associated with Viability in Saliva and Biofilm Formation.

ABSTRACT: Streptococcus sanguinis is a pioneer species of teeth and a common opportunistic pathogen of infective endocarditis. In this study, we identified a two-component system, S. sanguinis SptRS (SptRS Ss ), affecting S. sanguinis survival in saliva and biofilm formation. Isogenic mutants of sptRSs (SKsptR) and sptSSs (SKsptS) showed reduced cell counts in ex vivo assays of viability in saliva compared to those of parent strain SK36 and complemented mutants. Reduced counts of the mutants in saliva were associated with reduced growth rates in nutrient-poor medium (RPMI) and increased susceptibility to the deposition of C3b and the membrane attach complex (MAC) of the complement system, a defense component of saliva and serum. Conversely, sptRSs and sptSSs mutants showed increased biofilm formation associated with higher levels of production of H2O2 and extracellular DNA. Reverse transcription-quantitative PCR (RT-qPCR) comparisons of strains indicated a global role of SptRS Ss in repressing genes for H2O2 production (2.5- to 15-fold upregulation of spxB, spxR, vicR, tpk, and ackA in sptRSs and sptSSs mutants), biofilm formation, and/or evasion of host immunity (2.1- to 11.4-fold upregulation of srtA, pcsB, cwdP, iga, and nt5e). Compatible with the homology of SptR Ss with AraC-type regulators, duplicate to multiple conserved repeats were identified in 1,000-bp regulatory regions of downstream genes, suggesting that SptR Ss regulates transcription by DNA looping. Significant transcriptional changes in the regulatory genes vicR, spxR, comE, comX, and mecA in the sptRSs and sptSSs mutants further indicated that SptRS Ss is part of a regulatory network that coordinates cell wall homeostasis, H2O2 production, and competence. This study reveals that SptRS Ss is involved in the regulation of crucial functions for S. sanguinis persistence in the oral cavity.

SUBMITTER: Camargo TM

PROVIDER: S-EPMC5865015 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Novel Two-Component System of Streptococcus sanguinis Affecting Functions Associated with Viability in Saliva and Biofilm Formation.

Camargo Tarsila M TM Stipp Rafael N RN Alves Lívia A LA Harth-Chu Erika N EN Höfling José F JF Mattos-Graner Renata O RO

Infection and immunity 20180322 4

Streptococcus sanguinis is a pioneer species of teeth and a common opportunistic pathogen of infective endocarditis. In this study, we identified a two-component system, S. sanguinis SptRS (SptRS Ss ), affecting S. sanguinis survival in saliva and biofilm formation. Isogenic mutants of sptRSs (SKsptR) and sptSSs (SKsptS) showed reduced cell counts in ex vivo assays of viability in saliva compared to those of parent ...[more]

PMID: 29339459

Similar Datasets

Project description:The abilities of Streptococcus mutans to form biofilms and to survive acidic pH are regarded as two important virulence determinants in the pathogenesis of dental caries. Environmental stimuli are thought to regulate the expression of several genes associated with virulence factors through the activity of two-component signal transduction systems. Yet, little is known of the involvement of these systems in the physiology and pathogenicity of S. mutans. In this study, we describe a two-component regulatory system and its involvement in biofilm formation and acid resistance in S. mutans. By searching the S. mutans genome database with tblastn with the HK03 and RR03 protein sequences from S. pneumoniae as queries, we identified two genes, designated hk11 and rr11, that encode a putative histidine kinase and its cognate response regulator. To gain insight into their function, a PCR-mediated allelic-exchange mutagenesis strategy was used to create the hk11 (Em(r)) and rr11 (Em(r)) deletion mutants from S. mutans wild-type NG8 named SMHK11 and SMRR11, respectively. The mutants were examined for their growth rates, genetic competence, ability to form biofilms, and resistance to low-pH challenge. The results showed that deletion of hk11 or rr11 resulted in defects in biofilm formation and resistance to acidic pH. Both mutants formed biofilms with reduced biomass (50 to 70% of the density of the parent strain). Scanning electron microscopy revealed that the biofilms formed by the mutants had sponge-like architecture with what appeared to be large gaps that resembled water channel-like structures. The mutant biofilms were composed of longer chains of cells than those of the parent biofilm. Deletion of hk11 also resulted in greatly diminished resistance to low pH, although we did not observe the same effect when rr11 was deleted. Genetic competence was not affected in either mutant. The results suggested that the gene product of hk11 in S. mutans might act as a pH sensor that could cross talk with one or more response regulators. We conclude that the two-component signal transduction system encoded by hk11 and rr11 represents a new regulatory system involved in biofilm formation and acid resistance in S. mutans.

Dataset Information

Novel Two-Component System of Streptococcus sanguinis Affecting Functions Associated with Viability in Saliva and Biofilm Formation.

Publications

Novel Two-Component System of Streptococcus sanguinis Affecting Functions Associated with Viability in Saliva and Biofilm Formation.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets