van der Hoeven J S, Camp P J
Laboratory of Oral Microbiology, University of Nijmegen, The Netherlands.
Caries Res. 1993;27(1):26-30. doi: 10.1159/000261511.
Mixed continuous cultures of Streptococcus species were obtained, using complex carbohydrate (mucin) as a source of nutrients, to study the ecological effects of oxygen and the lactoperoxidase system. S. mutans NCTC 10449 was unable to grow as a pure culture on mucin, but attained a significant population size in the presence of S. oralis and S. sanguis strains. The cell densities of the anaerobic mixed cultures decreased when oxygen was supplied, and S. mutans was more suppressed by oxygen than were S. sanguis and S. oralis. However, the concentrations of hydrogen peroxide (30 mumol/l in the mixed culture of S. mutans with S. sanguis and 640 mumol/l in the culture with S. oralis) indicated a certain resistance of the organisms to hydrogen peroxide. Addition of lactoperoxidase and thiocyanate to the oxygen-supplied cultures had a differential effect on the streptococcal populations. While S. mutans was inhibited, and even disappeared in the culture with S. oralis, the growth of S. sanguis and S. oralis was unaffected. This latter observation was in accordance with the OSCN- reductase activities of these organisms. When hydrogen peroxide was also added together with lactoperoxidase and thiocyanate, a further inhibition of S. mutans in the culture with S. sanguis was observed. Under these conditions, S. oralis was also inhibited, perhaps by the strong accumulation of OSCN-, exceeding the capacity of the OSCN- reductase. The effects of lactoperoxidase on mixed cultures may reflect the situation in the mouth.(ABSTRACT TRUNCATED AT 250 WORDS)
利用复合碳水化合物（粘蛋白）作为营养源，获得了链球菌属的混合连续培养物，以研究氧气和乳过氧化物酶系统的生态效应。变形链球菌NCTC 10449无法在粘蛋白上作为纯培养物生长，但在口腔链球菌和血链球菌菌株存在的情况下能达到显著的种群数量。当提供氧气时，厌氧混合培养物的细胞密度降低，与血链球菌和口腔链球菌相比，变形链球菌受氧气的抑制作用更强。然而，过氧化氢的浓度（在变形链球菌与血链球菌的混合培养物中为30μmol/L，在与口腔链球菌的培养物中为640μmol/L）表明这些生物体对过氧化氢有一定的抗性。向供氧培养物中添加乳过氧化物酶和硫氰酸盐对链球菌种群有不同的影响。虽然变形链球菌受到抑制，在与口腔链球菌的培养物中甚至消失，但血链球菌和口腔链球菌的生长未受影响。后一观察结果与这些生物体的OSCN-还原酶活性一致。当同时添加过氧化氢以及乳过氧化物酶和硫氰酸盐时，在与血链球菌的培养物中观察到变形链球菌受到进一步抑制。在这些条件下，口腔链球菌也受到抑制，可能是由于OSCN-的强烈积累超过了OSCN-还原酶的能力。乳过氧化物酶对混合培养物的影响可能反映了口腔中的情况。（摘要截短至250字）
