一株口腔链球菌新种—寡发酵链球菌产过氧化氢特性的研究

从健康人口腔中分离的寡发酵链球菌(Streptococcus oligofermentans)能够产生大量的过氧化氢,可能具有抑制致病菌的潜力。为了研究该细菌产过氧化氢的特性,检测了其在不同生长时期和从不同底物产过氧化氢的能力。结果表明,寡发酵链球菌从对数生长早期就开始产过氧化氢,在对数生长后期及稳定期过氧化氢产量达到最高,随后下降。在PYG培养基中,寡发酵链球菌所产的过氧化氢主要来源于大豆蛋白胨和酵母提取物;而代谢终产物乳酸也可作为过氧化氢产生的底物。对3种可能与过氧化氢生成有关的氧化酶的酶活测定表明,寡发酵链球菌具有乳酸氧化酶(LOX)及NADH氧化酶(NOX)的活性,说明其过氧化氢的产生主要依赖于这两种酶的活力。

Characterization of hydrogen peroxide production by a novel oral streptococci,S. oligofermentans isolated from human oral cavity

High level of hydrogen peroxide was produced by S.oligofermentans,a novel oral streptococcus isolated from human oral cavity previously in our laboratory.To characterize the hydrogen peroxide production by S.oligofermentans,hydrogen peroxide yields at different growth phases and from different substrates were assayed.The results turned out that hydrogen peroxide production started at the beginning of logarithmic phase,and reached the maximal yield at the early stationary phase.Peptone and yeast extract could be the main substrates for hydrogen peroxide production.Moreover,lactate,as a fermentative product of glucose,can be another substrate for hydrogen peroxide production.Furthermore three oxidases activities possibly associated with H-2O-2 production were assayed,and both activities of lactate oxidase and NADH oxidase were detected under aerobic condition,while pyruvate oxidase activity was not detected in the permeabilized cells of S.oligofermentans,implying that S.oligofermentans could mainly rely on the two enzymes activities for H-2O-2 production.