In vitro and in vivo crosstalk between gut and pre-/pro-biotics

This PhD Thesis reports the results of my research in the laboratory of Prof. Ezio Ricca at the Department of Biology of the Federico II University of Naples, Italy. During these three years I focused my studies on the effects of molecules of various origin on intestinal epithelial cells and on the role of the microbiota in the gut homeostasis, using two different experimental approaches: in vitro and in vivo model systems. The Thesis is organized in four chapters addressing specific topics. The first three chapters are focused on the effect of bacterial molecules (putative peptides produced by intestinal isolates of Lactobacilli spp., CHAPTER 1; Competence and Sporulation Factor †"CSF produced by intestinal isolates of Bacillus subtilis strains, CHAPTER 2) or plant molecules (whole-leaf extracts of Aloe arborescens, CHAPTER 3) on epithelial cells (in vitro approach) with particular attention to intestinal epithelial cells, to better understand how they affect cellular proliferation and death. CHAPTER 4 analyzes the variations of intestinal microbiota composition in rats (in vivo approach) under different diet regimens, by using a metagenomic approach. Finally, in the APPENDIX of the thesis I report an unrelated study about the characterization of a pigmented spore-forming bacterium (Bacillus pumilus SF214) able to produce a hydrosoluble orange carotenoid.