Moorer W R, Ten Cate J M, Buijs J F
Department of Cariology and Endodontology, Academic Centre for Dentistry Amsterdam (ACTA), The Netherlands.
J Dent Res. 1993 Jun;72(6):1021-6. doi: 10.1177/00220345930720060501.
The main aim of this investigation was to challenge the idea that cariogenic streptococci do not calcify. Calcium uptake of calcification of Streptococcus mutans C180-2, proven to be an acidogenic and cariogenic strain, was compared with calcium uptake and calcification of Corynebacterium (Bacterionema) matruchotii, known as a ready calcifier. Bacteria were grown on Brain Heart Infusion Agar (BHIA) and on well-buffered semi-synthetic E-agar, both containing 1.4 mmol/L calcium, 2 g/L glucose, initial pH 7.4. Calcium uptake from BHIA by C. matruchotii (25 mmol Ca/kg wet bacterial cell mass), but not by S. mutans, was found. Grown as a plaque-like lawn on E-agar, the S. mutans cell mass concentrated calcium to 63 +/- 11 mmol/kg compared with 145 +/- 61 mmol/kg in C. matruchotii. X-ray diffraction confirmed the presence of crystalline apatite in the bacterial cell masses. Electron microscopy revealed crystals and mineralized deposits in both organisms. Heavy calcifications in some cells of S. mutans were seen. Calcification was partly inhibited by magnesium ion and by methanehydroxybisphosphonate. S. sobrinus 6715, as well as freshly isolated S. mutans and S. sobrinus from patients, concentrated very large quantities of calcium, up to 500-fold from the medium, when maintained for several weeks on E-agar of initial pH 7.6. Our observations widen the view on acidogenic bacteria as mineralization agents and support the notion that members of the mutans group of streptococci may be involved in events that trigger heavy intracellular calcifications and, possibly, dental calculus formation.
本研究的主要目的是对致龋性链球菌不会钙化这一观点提出质疑。将已被证实为产酸和致龋菌株的变形链球菌C180 - 2的钙化钙摄取情况，与已知易于钙化的牙龈棒杆菌（放线杆菌属）的钙摄取和钙化情况进行比较。细菌在脑心浸液琼脂（BHIA）和缓冲良好的半合成E - 琼脂上生长，两种培养基均含有1.4 mmol/L钙、2 g/L葡萄糖，初始pH值为7.4。发现牙龈棒杆菌能从BHIA摄取钙（25 mmol Ca/kg湿细菌细胞质量），而变形链球菌则不能。在E - 琼脂上以菌斑样菌苔形式生长时，变形链球菌细胞质量将钙浓缩至63±11 mmol/kg，而牙龈棒杆菌为145±61 mmol/kg。X射线衍射证实细菌细胞质量中存在结晶性磷灰石。电子显微镜显示两种生物体中均有晶体和矿化沉积物。在变形链球菌的一些细胞中可见重度钙化。钙化部分受到镁离子和甲烷羟基双膦酸盐的抑制。当在初始pH值为7.6的E - 琼脂上维持数周时，远缘链球菌6715以及从患者新分离出的变形链球菌和远缘链球菌会从培养基中大量浓缩钙，浓缩倍数高达500倍。我们的观察拓宽了对产酸细菌作为矿化剂的认识，并支持变形链球菌组的成员可能参与引发重度细胞内钙化以及可能形成牙结石的事件这一观点。
