99 Firmicutes Bacilli Bacillales GU968177 33 O1/7 Shigella flexneri 98 Proteobacteria Gammaproteobacteria Enterobacteriales GU968178 34 O1/7 Eggerthella lenta 96 Actinobacteria Coriobacteridae Coriobacteriales GU968179 35 O1/7 S. flexneri 98 Proteobacteria Gammaproteobacteria Enterobacteriales GU968180 39 O2/6 Clostridium scindens 98 Firmicutes Clostridia Clostridiales Epigenetics inhibitor GU968181 42 O2/7 Ruminococcus

sp. 96 Firmicutes Clostridia Clostridiales One strand only 45 V1/5 E. coli 98 Proteobacteria Gammaproteobacteria Enterobacteriales GU968182 46 V1/5 E. coli 98 Proteobacteria Gammaproteobacteria Enterobacteriales GU968183 48 V1/5 E. coli 99 Proteobacteria Gammaproteobacteria Enterobacteriales GU968184 49 V1/5 E. coli 99 Proteobacteria Gammaproteobacteria Enterobacteriales GU968185 50 V1/6 E. coli 99 Proteobacteria Gammaproteobacteria Panobinostat mouse Enterobacteriales 885 bp Discussion The measurements made here of rates of NH3 production from different amino acid-containing substrates, the influence of monensin on these rates, and the properties of bacteria isolated on the basis of being able to grow on Trypticase have important implications for understanding the biochemistry

and microbial ecology of amino acid metabolism, and therefore the production of potentially hazardous products that can be formed from amino acids and related nitrogenous compounds in the human colon [2]. These results add to the substantial body of knowledge generated by Smith and Macfarlane [1, 8–11, 20] in the following respects. Ammonia production from peptides and amino acids was compared in diluted fresh samples of faeces in a similar way, with very similar results to earlier studies. However, utilization of individual amino acids from peptides was also compared, using faecal samples from both vegetarians and omnivorous donors. The differences may be explained by different permease mechanisms for peptides and amino acids. The effects of monensin on NH3

production and amino acid dissimilation were shown, providing clues about the biochemistry and microbial ecology of amino acid dissimilation. ID-8 Finally, the bacteria that were enriched by growth on peptides or amino acids as energy source were isolated and identified based on 16S rRNA gene sequences. Similar methodology in the rumen revealed the HAP population, with significant implications for animal nutrition. The results imply that, unlike in the rumen, there is no significant population of ‘hyper-ammonia-producing’ bacteria [18]. Instead, the species that were enriched by growth on peptides and amino acids in the absence of carbohydrates include several pathogenic species that have important implications for health. Ammonia production rates from Trypticase were higher than from casein or from a corresponding amino acid mixture.