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Applied and Environmental Microbiology, April 2009, p. 2517-2527, Vol. 75, No. 8
0099-2240/09/$08.00+0 doi:10.1128/AEM.02367-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
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Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida 32610,1 Dental Research Institute and Department of Orthodontics, School of Dentistry, Seoul National University, 28-22 Yungeon-Dong, Jongro-Gu, Seoul 110-768, Republic of Korea2
Received 15 October 2008/ Accepted 15 February 2009
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.
Published ahead of print on 27 February 2009.
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