The main objective of this class experiment is to show the time-dependent consumption of a fermentable sugar (glucose) in the presence and absence of a non-fermentable sugar (xylose) by bacteria in anaerobic conditions. The observation of the pH decrease due to acid production and the turbidity increase as a result of cell multiplication, both in function of time, enables an interesting discussion regarding the metabolic pathways and the products of anaerobic fermentation of carbohydrates. Also the time-dependent disappearance of glucose due to its metabolic consumption is compared with the non-disappearance of xylose and permits a discussion of the function of glycolysis and pentose phosphate pathways as metabolic routes.
The main objective of this class experiment is to show the influence of carbon source and of different fluoride concentrations on the biofilm formation by the bacterium Streptococcus mutans. The observation of different biofilm morphology as a function of carbon source and fluoride concentration allows an interesting discussion regarding the metabolic pathways that lead to cavity development, about the role of fluoride on this disease prevention, and also on the importance of biofilm formation to the cariogenic potential of this bacterium, one of the main responsible for this multifatorial disease appearance. On addition to that, the low execution cost and the simple technical apparatus makes this experiment easy to perform.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.