@article{mbs:/content/journal/micro/10.1099/00221287-117-1-57, author = "Welling, Gjalt W. and Groen, Gerda and Tuinte, Jan H. M. and Koopman, Joop P. and Kennis, Henriette M.", title = "Biochemical Effects on Germ-free Mice of Association with Several Strains of Anaerobic Bacteria", journal= "Microbiology", year = "1980", volume = "117", number = "1", pages = "57-63", doi = "https://doi.org/10.1099/00221287-117-1-57", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-117-1-57", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", abstract = "The effects of the following changes throughout the association of germ-free mice with increasing numbers of anaerobic bacteria were studied: (i) elution patterns obtained by gel-filtration chromatography of caecal diffusates; (ii) concentration of β-aspartylglycine in caecal and faecal contents; (iii) polypeptide patterns obtained by sodium dodecyl sulphatepolyacrylamide gel electrophoresis of caecal supernatants; (iv) free amino acid content of caecal supernatants; (v) faecal bile acids, analysed by gas-liquid chromatography; (vi) colonization-resistance. The results indicate that monitoring the normalization (association) process can be accomplished in several ways, but the level of colonization-resistance is most easily measured by high-voltage paper electrophoresis of faecal supernatants to determine the concentration of β-aspartylglycine. During association, the concentration of β-aspartyl-glycine decreased and became undetectable after association with 40 to 50 different strains of bacteria. There was a good negative correlation between the level of colonization-resistance and the concentration of β-aspartylglycine.", }