Browsing by Subject "arteries"

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    Effects of Nicotine on Aerobic and Anaerobic Serotype K Streptococcus mutans Biofilm Formation
    (Office of the Vice Chancellor for Research, 2015-04-17) Quint, Nicole; Gomez, Grace; Gregory, Richard L.
    Atherosclerosis is a specific form of arteriosclerosis where the walls of arteries began to thicken as a result of bacterial invasion and accumulation of inflammatory white blood cells. There could be a direct correlation of atherosclerosis and the intake of nicotine. Nicotine has been reported to increase the amount of the cariogenic oral bacteria known as Streptococcus mutans; thus possibly leading to an increase of dental caries. Serotype K S. mutans has been associated strongly with atherosclerosis. Objective: This study focused on the biofilm formation of S. mutans serotype K when incubated in various dilutions of nicotine. Methods: S. mutans UA159 (stereotype C), and stereotype K strains 89, 52, and 51 were cultured in tryptic soy broth (TSB) overnight and then added to dilutions of TSB with 1% sucrose (TSBS) containing concentrations of nicotine between 0 and 32 mg/ml. Each dilution was added to 96-well microtiter plates, inoculated with bacteria and incubated for 24 hours aerobically at 37oC in 5% CO2 and anaerobically. The plates were treated with formaldehyde, crystal violet, and isopropanol and biofilm formation was measured at an absorbance of 490 nm. Results: Strains UA159, 89, 52, and 51 all demonstrated significantly higher biofilm formation (p<0.05) at a nicotine dilution of 8 mg/ml. When comparing the anaerobic results to the aerobic results, anaerobic incubation increased the overall biofilm formation across the majority of nicotine dilutions. Conclusion: It was established that when S. mutans strains UA159, 89, 52, and 51 were incubated anaerobically and aerobically biofilm formation was enhanced. Smoking can lead to a higher population of S. mutans in the oral cavity that potentially has traits of significantly enhanced biofilm formation when presented with moderately high levels of nicotine which may lead to increased binding to endothelial cells contributing to atherosclerosis.
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    Streptococcus mutans Binding to Collagen and Fibrinogen in Nicotine
    (Office of the Vice Chancellor for Research, 2015-04-17) Kristoff, Sylvie N.; Gomez, Grace; Gregory, Richard L.
    Introduction: Our overall goal is to find the mechanism for atherosclerosis. Smokers have increased incidence of atherosclerosis. Atherosclerosis occurs when there is a build up of plaque in the arteries. There is evidence that Streptococcus mutans help cause this blockage. We have already proven that S. mutans produces more biofilm in certain concentrations of nicotine. Also, we have found that nicotine upregulates S. mutans binding to proteins in certain concentrations; other labs have also demonstrated this. The intent of this study was to evaluate the binding of S. mutans to both collagen type I and fibrinogen, which are both proteins that are already present on the surface of endothelial cells lining arteries. Methods: S. mutans UA159 was cultured in 0.00-4.00 mg/mL nicotine. The cells were killed in formaldehyde and then coated with biotin. The proteins studied were plated (1 ug/ml) on 96-well microtiter plates. In order to block the empty spaces that the protein did not bind to, 1% BSA in sodium bicarbonate buffer was added to the plate. Each nicotine dilution of S. mutans was added to the plate and the amount of binding was assessed. Extra-avidin HRP and OPD were added to the plate and the intensity was measured at an absorbance of 490 nm using a spectrophotometer. Results: The intensity was directly related to the number of cells bound to the proteins. There was a significant increase in S. mutans binding when compared to the baseline for both collagen type I and fibrinogen. The binding was highest when S. mutans were cultured in 2 and 4 mg/mL nicotine. Conclusions: The data collected suggests that collagen type I and fibrinogen contribute to the mechanism of atherosclerosis. When S. mutans are cultured in moderately high concentrations of nicotine, more binding of the bacteria to these proteins occurs.