Gastrointestinal tract, microbial

Zoetendal E, Akkermans A, Akkermans-Van Vleit W, De Visser J, De Vos W. The host genotype affects the bacterial community in the human gastrointestinal tract. Microbial Ecol Health Dis. 2001 13 129-134. 

This occurs in the seromucous secretions such as saliva, tears, nasal secretions, sweat, colostrum and secretions of the lung, urinogenital and gastrointestinal tracts. Its purpose appears to be to protect the external surfaces of the body from microbial attack. It occurs as a dimer in these secretions but as a monomer in human plasma, where its function is not known. The function of IgA appears to be to prevent the adherence of microorganisms to the surface ofmucosal cells thus preventing them entering the body tissues. It is protected from proteolysis by combination with another protein—the secretory component. 

It has recently been shown (14) that nitrate from food can be detected in the feces of germfree animals but not in the feces of conventional animals. This result and the results of Witter et al. (18-20) suggest that nitrate is available in the lower gastrointestinal tract and is metabolized by the microbial flora. The intestine may thus be a site for the endogenous formation of N-nitroso compounds. 

Savage DC Microbial ecology of the gastrointestinal tract. Annu Rev Microbiol 1977 31 107-133. 

Hill M Normal and pathological microbial flora of the upper gastrointestinal tract. Scand J Gastroenterol Suppl 1985 111 1-6. 

The studies on phospholipid bilayers with defined amounts of charged component are helpful to explain the partition characteristics in biological membranes. Liposome water partition data of propranolol in lipids from kidney epithelial cells (a common model system in pharmaceutical sciences for the uptake into the gastrointestinal tract) have been successfully described with partition models developed for pure bilayers or defined mixtures [159]. Since lipophilic cations and anions can be used as probes for the membrane potential, their interaction with microbial and mitochondrial membranes has been studied... 

Toxicology. Propionic acid is an irritant to skin, eyes, and mucous membranes. Propionic acid is a normal intermediary metabolite during the oxidation of fatty acids. It occurs ubiquitously in the gastrointestinal tract as an end product of microbial digestion of carbohydrates. It represents up to 4% of the normal total plasma fatty acids. ... 

Apajalahti, J. and Kettunen, A. (2003) Analysis and dietary modulation of the microbial community in the avian gastrointestinal tract. In Proceedings of the 26th Technical Turkey Conference. Turkeys Magazine, Manchester, UK, 24-25 May, 2003, pp. 49-55. 

Table IV. Effect of Diet on Microbial Population of Gastrointestinal Tract...

Hoskins, L.C. 1992. Mucin degradation in the human gastrointestinal tract and its significance to enteric microbial ecology. Eur. J. Gastroenterol. Hepatol. 5, 205-213. 

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