Extracellular-nucleotide metabolisms of oral microorganisms

点击翻译按钮获取中文摘要

It has been reported that various bacteria inhabit in an oral cavity and some of these bacteria may cause several diseases in the other area. Especially Streptococcus sanguinis has been detected in the inflammation part of endocarditis and in various abscess regions. In this study we examined whether oral streptococci metabolize extra-cellular nucleotide which is supposed to exist in abscess regions. As a result, it was confirmed that Streptococcus sanguinis, Streptococcus gordonii and Streptococcus salivarius metabolized CMP and produced the ammonia and inorganic phosphate. Therefore, we examined the metabolic difference both these two streptococcal groups in detail. Both bacteria group had significant degree of cytidine deaminase activity in the cell-free extracts. Although S. sanguinis, S. gordonii and S. salivarius contained membrane-bound 5'-nucleotidase activity, but mutans streptococci did not contain the activity. The 5'-nucleotidase activity in the cell-free extract of S. sanguinis fell off significantly by the oxygen flash. Certain kind of active oxygen may be generated and inactivate the 5'-nucleotidase. AMP, GMP, UMP, deoxyAMP, deoxyCMP, deoxyGMP were decomposed by S sanguinis cells and inorganic phosphate was produced. And it was confirmed that S. sanguinis cells generated ammonia from (deoxy-)AMP, (deoxy-)CMP. In this study we found that S. sanguinis, S. gordonii and S. salivarius could metabolize extra-cellular 5'-(deoxy) ribonucleotide. It was considered that these facts are important to understand the ecosystem of the bacteria in various regions of the body as well as the dental plaque.