Date of Award

Spring 2012

Document Type



Life & Environmental Sciences

First Advisor

Daniel Gretch

Second Advisor

Sam Alvey

Third Advisor

Chris Fuller


Studies have repeatedly focused on the positive effects of probiotic bacteria on mammalian gastrointestinal health and have confirmed the ability of probiotics, like lactobacilli, to decisively influence the intestinal microbiota balance and the gut immune system. The four species of lactobacilli used in this study, L. fermentum, L. acidophilus, L. gasseri, and L. rhamnosus, are known to stimulate the integrity of the intestinal barrier by promoting the expression of the adherence junction protein E-cadherin. Another major influence on E-cadherin concentrations is the presence of the transcription repressor SNAIL. This study aims to further investigate the mechanisms by which these species of lactobacilli and the SNAIL transcription factors exert regulation on E-cadherin. The presence of SNAIL transcription factors down-regulate the expression of E-cadherin and this is associated with various carcinomas. If it is found that the lactobacilli and the SNAIL factors regulate E-cadherin expression by similar mechanisms (these specific miRNA), potential lactobacilli therapies could be utilized in cancer treatments. This study did not reveal direct relationships between specific lactobacilli and SNAIL factors analyzed. Further trials should be done with additional combinations. Still, previous claims about the regulatory functions of the SNAIL transcription factors and lactobacilli were confirmed.