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Analysis of the roles of the transchptional regulators VicRK and CovR in the susceptibility of Streptococcus mutans and Streptococcus sanguinis to opsonization by the complement system

Grant number: 12/50966-6
Support type:Regular Research Grants
Duration: October 01, 2012 - September 30, 2014
Field of knowledge:Health Sciences - Dentistry
Principal researcher:Renata de Oliveira Mattos Graner
Grantee:Renata de Oliveira Mattos Graner
Home Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil


Streptococcus mutans (SM) e Streptococcus sanguinis (SS) are common bacterial species of the human oral microbiota, which are involved in the pathogenesis of dental caries. The teeth surfaces are the major ecological niches of these species. While SM are considered the major pathogens of dental caries, SS are classically defined as a beneficial commensal species, because of its ability to inhibit the establishment of SM in dental biofilms. However, both species are opportunistic pathogens of bacterial endocarditis resulted from bacteremias from oral origin. To be transmitted and to occupy their ecological niches, these microorganisms need to persist in saliva and to physiologically adapt to the biophysical conditions of their host sites. This complex process involves changes in bacterial transcriptomes in response to environmental stimuli, which include host defense factors. Transcriptomic adaptations in response to environmental stimuli are controlled by two-component systems (TCS) in bactéria. A typical TCS is composed by a membrane histidine kinase (HK) and an intracellular response regulator protein (RR). SM has the TCS designated VicRK (vic of Virulence control) and the orphan RR CovR (cov of control of virulence), which are conserved among pathogenic species of Streptococcus. In Streptococcus pneumoniae and Streptococcus pyogenes, VicRK and CovR regulate genes involved in bacterial evasion of host immune factors, a function that seems to also occur in SM. Recently, we also identified VicRK and CovR in SS. This project aims to investigate the roles of VicRK and CovR in the evasion of SM and SS to human immune factors. To that purpose, vicRK and covR mutants obtained in S. mutans UA159 and in S. sanguinis SK36 will be characterized regarding complement fixation and phagocytosis by PMN in presence of human blood. (AU)

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Scientific publications (4)
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
ALVES, LIVIA A.; DE CARLI, THAIS R.; HARTH-CHU, ERIKA N.; MARIANO, FLAVIA S.; HOFLING, JOSE F.; STIPP, RAFAEL N.; MATTOS-GRANER, RENATA O.. Oral streptococci show diversity in resistance to complement immunity. Journal of Medical Microbiology, v. 68, n. 4, p. 600-608, . (17/19899-4, 12/04222-5, 09/50547-0, 15/12940-3, 12/50966-6, 18/02054-4, 13/07098-6, 15/07237-1)
ALVES, LIVIA A.; HARTH-CHU, ERIKA N.; PALMA, THAIS H.; STIPP, RAFAEL N.; MARIANO, FLAVIA S.; HOEFLING, JOSE F.; ABRANCHES, JACQUELINE; MATTOS-GRANER, RENATA O.. The two-component system VicRK regulates functions associated with Streptococcus mutans resistance to complement immunity. Molecular Oral Microbiology, v. 32, n. 5, p. 419-431, . (12/04222-5, 09/50547-0, 15/12940-3, 12/50966-6, 15/07237-1)
MATTOS-GRANER, RENATA O.; DUNCAN, MARGARET J.. Two-component signal transduction systems in oral bacteria. JOURNAL OF ORAL MICROBIOLOGY, v. 9, . (12/50966-6, 15/12940-3)
HARTH-CHU, ERIKA N.; ALVES, LIVIA A.; THEOBALDO, JESSICA D.; SALOMAO, MARIANA F.; HOFLING, JOSE F.; KING, WILLIAM F.; SMITH, DANIEL J.; MATTOS-GRANER, RENATA O.. PcsB Expression Diversity Influences on Streptococcus mitis Phenotypes Associated With Host Persistence and Virulence. FRONTIERS IN MICROBIOLOGY, v. 10, . (17/19899-4, 15/12940-3, 12/04222-5, 18/02054-4, 15/07237-1, 09/50547-0, 12/50966-6)

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