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Role of D‐alanylation of Streptococcus mutans lipoteichoic acid in interspecies competitiveness
Author(s) -
Wu Minjing,
Huang Shan,
Du Jingyun,
Jiang Shan,
Cai Zhiyu,
Zhan Ling,
Huang Xiaojing
Publication year - 2021
Publication title -
molecular oral microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 77
eISSN - 2041-1014
pISSN - 2041-1006
DOI - 10.1111/omi.12344
Subject(s) - streptococcus mutans , biofilm , mutant , streptococcus gordonii , microbiology and biotechnology , streptococcus sanguinis , antimicrobial , bacteria , lipoteichoic acid , chemistry , wild type , biology , biochemistry , staphylococcus aureus , genetics , gene
Abstract Background The D‐alanylation of lipoteichoic acid (LTA) is essential for the physiological metabolism of Streptococcus mutans ( S. mutans ). This study was designed to investigate the influence of D‐alanylation of LTA on interspecies competitiveness of S. mutans . Methods The process of D‐alanylation was blocked by the inactivation of dltC . Agar competition assays, conditioned medium assays, and qRT‐PCR were used to evaluate the production of antimicrobial compounds in S. mutans mutant. Dual‐species biofilm was formed to investigate the competitiveness of S. mutans mutant cocultured with S. sanguinis or S. gordonii . Results S. mutans mutant could not produce antimicrobial compounds efficiently when cocultured with commensal bacteria (* p < 0.05). The mutant showed compromised competitiveness in dual‐species biofilms. The ratio of the mutant in dual‐species biofilms decreased, and the terminal pH of the culture medium in mutant groups (mutant+S. sanguinis / S. gordonii ) was higher than that in wild‐type groups (* p < 0.05). Scanning electron microscope ( SEM ) showed weaker demineralization of enamel treated with dual‐species biofilms consisting of mutant and commensal bacteria. Conclusion D‐Alanylation is involved in interspecies competitiveness of S. mutans within oral biofilm by regulating mutacins and lactic acid production, which may modulate the profiles of dental biofilms. Results provide new insights into dental caries prevention and treatment.