Int J Oral Biol.  2015 Dec;40(4):217-221. 10.11620/IJOB.2015.40.4.217.

Streptococcus mutans Strains Isolated in Korea Can Hardly Metabolize Exogenous Nitric Oxide

• Lee HJ
• Bang IS

• KMID: 2133227
• DOI: http://doi.org/10.11620/IJOB.2015.40.4.217

Abstract

Cariogenic Streptococcus mutans encounters a variety of host defense factors produced in oral cavity. Nitric oxide (NO) and NO-mediated reactive nitrogen species are potential antimicrobials of innate immunity that can threaten the fitness of S. mutans in their ecological niches. Streptococcal strategies to detoxify cytotoxic NO, which allow S. mutans to persist in caries or other environments of the oral cavity, remain unknown. In this study, we directly measured NO consumption rates of S. mutans isolated in Korea. Surprisingly, all S. mutans strains were unable to consume exogenous NO efficiently, while an intracellular parasite Salmonella enterica serovar Typhimurium expressing the NO-metabolizing enzyme flavohemoglobin consumed most of the NO. This result suggested that S. mutans has alternative detoxification systems for tolerating NO-induced nitrosative stresses.

Keyword

nitric oxide; nitric oxide consumtion; oral cavity; Streptococcus mutans

MeSH Terms

Immunity, Innate
Korea*
Mouth
Nitric Oxide*
Parasites
Reactive Nitrogen Species
Salmonella enterica
Streptococcus mutans*
Streptococcus*
Nitric Oxide
Reactive Nitrogen Species