A ROUTINE DETERMINATION OF THE OPTICALLY ACTIVE ISOMERS OF LACTIC ACID FOR BACTERIAL CLASSIFICATION.
The quantity of L(+)-isomer of lactic acid is determined with L(+)-specific lactic dehydrogenase. Comparison with the total amount of lactic acid determined chromatographically is used as a rapid and accurate replacement for the classical determination of optically active isomers of lactic acid for classification of lactic acid bacteria.
Faecal DL-lactate concentration in 100 gastrointestinal patients.
The relation between faecal DL-lactate and intestinal inflammation or malabsorption was evaluated in 100 nonselected inpatients at a referral center for gastrointestinal disorders. Twenty-one (21%) had DL-lactate concentrations (range, 8-95 mmol/l) above the 95% limit (6.1 mmol/l) in healthy individuals. Inflammatory bowel disease with active proctitis was associated with increased faecal DL-lactate in 11 of 15 patients (73%) (mean, 32 mmol/l; range, 8-95 mmol/l) and in the 1 patient with pouchitis (8 mmol/l), whereas only 1 of 8 patients (13%) with active inflammatory bowel disease without proctitis had L-lactate elevation (25 mmol/l). Among 26 patients with malabsorption and quiescent or noninflammatory bowel disease, 3 of 17 (18%) with preserved colonic function and 3 of 9 (33%) with jejunostomy had increased faecal lactate. Only 2 of 50 (4%) patients with neither active inflammatory bowel disease nor malabsorption had faecal DL-lactate elevation. In vitro bacterial fermentation of most dietary polysaccharides did not cause accumulation of lactate, corresponding to a lack of correlation between faecal carbohydrate excretion and lactate accumulation. An isolated increase in faecal L-lactate was observed in 6 of 13 patients with inflammatory bowel disease, whereas D-lactate was not increased without a simultaneous increase of the L-lactate isomer. In conclusion, the faecal lactate concentration was frequently increased in patients with inflammatory bowel disease and proctitis, occasionally increased in patients with severe malabsorption, and often normal in patients with quiescent inflammatory bowel disease or localized Crohn's ileitis.(ABSTRACT TRUNCATED AT 250 WORDS)
Concentration of amino acids in wine after the end of fermentation by Saccharomyces cerevisiae strains
Both quantitative and qualitative differences in the utilization and release of assimilable nitrogen by two wine strains of Saccharomyces cerevisiae (cerevisiae and capensis) under different conditions of oxygen were observed. These differences were influenced by the presence of oxygen at the beginning of the fermentation, and by the strain of S cerevisiae. The release of some amino acids post-fermentation may be the result of reoxidation of NAD(P)H in order to maintain a normal redox balance. Copyright © 2003 Society of Chemical Industry