Ahn Sug-Joon, Ahn Sang-Joon, Browngardt Christopher M, Burne Robert A
Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida 32610, USA.
Appl Environ Microbiol. 2009 Apr;75(8):2517-27. doi: 10.1128/AEM.02367-08. Epub 2009 Feb 27.
Oxygen has a potent influence on the expression of genes and the activity of physiological and biochemical pathways in bacteria. We have found that oxygen significantly altered virulence-related phenotypic properties of Streptococcus mutans, the primary etiological agent of human dental caries. Transport of glucose, fructose, or mannose by the sugar:phosphotransferase system was significantly enhanced by growth under aerobic conditions, whereas aeration caused an extended lag phase and slower growth of S. mutans in medium containing glucose, fructose, or mannose as the carbohydrate source. Aeration resulted in a decrease in the glycolytic rate and enhanced the production of intracellular storage polysaccharides. Although aeration decreased the acid tolerance of S. mutans, aerobically grown cells had higher F-ATPase activity. Aeration altered biofilm architecture but did not change the ability of S. mutans to interact with salivary agglutinin. Growth in air resulted in enhanced cell-associated glucosyltransferase (Gtf) activity at the expense of cell-free Gtf activity. These results demonstrate that S. mutans can dramatically alter its pathogenic potential in response to exposure to oxygen, suggesting that the phenotype of the organism may be highly variable in the human oral cavity depending on the maturity of the dental plaque biofilm.
氧气对细菌中基因的表达以及生理和生化途径的活性具有强大的影响。我们发现，氧气显著改变了变形链球菌的毒力相关表型特性，变形链球菌是人类龋齿的主要病原体。在有氧条件下生长时，糖：磷酸转移酶系统对葡萄糖、果糖或甘露糖的转运显著增强，而通气会导致变形链球菌在以葡萄糖、果糖或甘露糖作为碳水化合物来源的培养基中出现延长的延迟期和较慢的生长速度。通气导致糖酵解速率降低，并增强了细胞内储存多糖的产生。尽管通气降低了变形链球菌的耐酸性，但需氧生长的细胞具有更高的F-ATP酶活性。通气改变了生物膜结构，但没有改变变形链球菌与唾液凝集素相互作用的能力。在空气中生长导致细胞相关葡糖基转移酶（Gtf）活性增强，而以无细胞Gtf活性为代价。这些结果表明，变形链球菌可以根据暴露于氧气的情况显著改变其致病潜力，这表明该生物体的表型在人类口腔中可能会因牙菌斑生物膜的成熟度而高度可变。
