Ruby J D, Goldner M, Hargreaves J A
Rev Can Biol. 1978 Dec;37(4):273-89.
Streptococcus mutans converts low levels of sucrose to lactic acid, but at high levels favours synthesis of glucans for plaque accumulation. Thus, the continued exposure to sucrose fluxes would select microorganisms in the oral cavity (S. mutans being a prototype) with highly specialized adaptation and potential dental caries activity. The bacteria that have evolved physiological systems to function efficiently under these conditions are the lactic acid bacteria. These organisms survive in environments where carbohydrate availability is constantly changing. High tolerances to acidic environments may be an important determinant in establishing the ecology of the carious lesion. Also, the intercellular polysaccharide storgae (glycogenamylopectin) and extracellular polymer reserves (levan and soluble glucan) are important during carbohydrate depletion. Further, the formation of insoluble glucans is a prerequisite for the caries process on smooth surfaces of teeth through plaque development. These conditions could result in an increase in S. mutans and cariogenic microorganisms. As a result, this process may be best understood as a manifestation of an amphibiotic shift.
变形链球菌可将低水平的蔗糖转化为乳酸，但在高水平蔗糖条件下则有利于合成葡聚糖以促进牙菌斑的积累。因此，持续接触蔗糖通量会在口腔中选择具有高度专业化适应性和潜在致龋活性的微生物（变形链球菌就是一个典型例子）。在这些条件下进化出能高效发挥功能的生理系统的细菌是乳酸菌。这些微生物在碳水化合物可利用性不断变化的环境中生存。对酸性环境的高耐受性可能是确定龋损生态的一个重要决定因素。此外，细胞内多糖储存（糖原支链淀粉）和细胞外聚合物储备（果聚糖和可溶性葡聚糖）在碳水化合物耗尽期间很重要。此外，不溶性葡聚糖的形成是通过牙菌斑形成在牙齿光滑表面发生龋病过程的一个先决条件。这些情况可能导致变形链球菌和致龋微生物增加。因此，这个过程最好理解为两栖转变的一种表现。
