[2] These bacterial species belong mostly to genera that are placed in one of the four phyla, namely Firmicutes, Bacteroidetes, Palbociclib purchase Proteobacteria, and Actinobacteria,[3] with little representation from the other bacterial phyla. GI tract is sterile at birth. Colonization begins soon thereafter, initially with flora acquired from the mother’s vaginal canal and thereafter from the surrounding environment. An individual’s gut microbiota is generally well established by 1 year

of age and remain unchanged through life except for minor temporary fluctuations.[4] The composition of adult gut microbiota varies widely between individuals and depends on several factors, including host genetics, diet, and other environmental factors. Thus, a particular individual’s gut harbors

a subset of about 150–200 bacterial species from among those referred to above.[2] Gut microbiota plays several important roles in the host’s health. It supplements the host’s nutritional needs through breakdown and absorption of complex dietary carbohydrates, which human enzymes cannot digest, as also synthesis of some essential substances, for example vitamin K. In addition, it helps maintain the integrity of intestinal epithelial barrier through production of short-chain fatty acids, particularly butyrate, that BAY 57-1293 molecular weight are trophic for colonic epithelial cells and help epithelial restitution,[5] and contributes to maturation of host immune system, including development of Peyer’s patches, mucosal lymphoid follicles, and antibody-secreting plasma cells.[6] In addition, these organisms protect the host against pathogenic microbes through competition for adhesion sites and nutrients, and production of antimicrobial agents. Liver develops as a bud from the embryonic foregut and maintains

a close two-way liaison with the GI tract throughout life. Venous blood from the gut reaches the liver via portal vein, carrying with it products of gut flora and of host’s immunological responses to these organisms. In turn, the liver produces bile that flows to the gut to affect the abundance and distribution of various organisms in the latter’s lumen. This close relationship of liver and Isoconazole gut implies that gut flora may play a role in the pathogenesis of liver diseases, and their study may allow identification of newer preventive and therapeutic strategies against these diseases. This article reviews in brief the techniques used to study gut microbiota and current knowledge about the role of microbiota in liver disease. Initial studies on composition of gut microbiota were based on culture of intestinal biopsy specimens, luminal contents, or feces. In recent years, these have largely been replaced by molecular methods.