Submitted to: Current Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/10/1997
Publication Date: N/A
Interpretive Summary: Streptococcus bovis is a rapidly growing gut bacterium that produces an abundance of lactic acid. The overgrowth of S. bovis in the gut causes a decrease in gut pH, acute indigestion, sore feet and even death of the animal. Commercially available feed additives have not been effective in controlling S. bovis. In this paper, we showed that 2-deoxyglucose, a form mof glucose that cannot be utilized by bacteria or animals, could promote the breakdown and death of S. bovis. Further work is needed to more precisely define the site of action, but this information might eventually lead to a means of controlling S. bovis and protecting animals from acute indigestion.
Technical Abstract: The non-metabolizable glucose analog, 2-deoxyglucose (2-DG) decreased the growth rate and optical density of Streptococcus bovis JBI 20%, but it had an even greater effect on stationary phase cultures. Control cultures receiving only glucose (2 mg/ml) lysed very slowly (<5% decline inoptical density in 48 h), but cultures that had been grown with glucose and 2-DG (2 2mg/ml each) lysed much faster (>85% decline in optical density in 48 h). 2 DG -mediated lysis was dependent on the stage of growth. 2-DG had its greatest effect when it was added at inoculation. If 2-DG was added at later times, less lysis was observed, and cells that were given 2-DG just prior to stationary phase were unaffected. Cells that were grown with glucose and 2-DG were more susceptible to cell wall degrading-enzymes (lysozyme and mutanolysin) than cells that had been grown only with glucose. Cultures growing with glucose and 2-DG had nearly as much ATP and as high a membrane potential as control cultures having only glucose. Sodium fluoride (5 mM) decreased the growth rate, intracellular ATP, and membrane potential of S. bovis JB1, it did not promote lysis. The ionophores valinomycin and nigericin (5 uM each) and the protonophore, 3,3',4',5-tetrachlorosalicylanilide (TCS, 5uM) completely inhibited growth, decreased ATP by at least 50%, and completely dissipated the membrane potential, but these inhibitors did not promote lysis. The proteinase inhibitor phenylmethylsulfonyl fluoride (PMSF, 1 mM) caused a small decline in ATP and membrane potential, but it did not promote lysis. Based on these results, 2-deoxyglucose has a direct effect on the cell wall synthesis of S. bovis JB1.