Journal of Oral Tissue Engineering

ORIGINAL ARTICLE
Variations of Nitrate-reducing Activity in Oral Rothia mucilaginosa

Chiho MASHIMO1, Osamu TSUZUKIBASHI2, Satoshi UCHIBORI3 and Takayuki NAMBU1

1Department of Bacteriology, Osaka Dental University, Osaka, Japan
2Department of Microbiology and Immunology, Nihon University,
School of Dentistry at Matsudo, Chiba, Japan
3Department of Crown Bridge Prosthodontics, Nihon University,
School of Dentistry at Matsudo, Chiba, Japan



J Oral Tissue Engin 2015; 13(1): 18-26

SYNOPSIS
It is well-known that nitric oxide resulting from the reduction of salivary nitrate plays a beneficial antimicrobial role in the oral cavity. Recent genomic analysis of nitrate reductase-positive bacteria in the oral cavity revealed that certain bacterial species (members of Veillonella, Actinomyces, Rothia, Staphylococcus, Corynebacterium, etc.) have the capacity to reduce nitrate. One such species that was notable for its high reducing activity was Rothia mucilaginosa. Recent metagenomics studies have shown a strong correlation between the presence of oral Rothia spp. within oral subgingival bacterial communities and periodontal health. We hypothesize that this correlation results partly from the microbicidal efficacy of the nitrate-reducing system in Rothia. In this study, we evaluated the nitrate reduction abilities of three R. mucilaginosa strains individually using a chromogenic substrate method based on the Griess reaction and a NOx analyzer. We found that, intriguingly, the three strains exhibited different levels of nitrate-reducing activity. This is the first study to reveal the variation in nitrate-reducing capacity among individual oral R. mucilaginosa strains.

Key words: Rothia mucilaginosa, oral bacteria, nitrate reducing activity, nitrate, nitrite



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