The colorimetric determination of lactic acid in biological material.
01 Apr 1941-Journal of Biological Chemistry (American Society for Biochemistry and Molecular Biology)-Vol. 138, Iss: 2, pp 535-554
About: This article is published in Journal of Biological Chemistry.The article was published on 1941-04-01 and is currently open access. It has received 3422 citations till now. The article focuses on the topics: Lactic acid.
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1,190 citations
TL;DR: A preparation of isolated small intestine of the rat or golden hamster is described which permits convenient measurement ofpiration and glycolysis during periods of active transference of substances across the wall.
Abstract: A preparation of isolated small intestine of the rat or golden hamster (Mesocricetus auratus) is described which permits convenient measurement ofrespiration and glycolysis during periods of active transference of substances across the wall. The difficulty of adequate oxygenation is overcome by everting a piece of intestine, tying it at both ends and filling it with sufficient fluid to distend the wall. The eversion exposes the highly active mucosa to the well-oxygenated suspending medium, while the distension increases the surface area of the sac and reduces the thickness of the sac wall. The oxygenation of the inner layer of the serosal surface is facilitated by an oxygen bubble which is introduced into the sac along with the inner fluid. The relatively small volume of fluid contained in the sac (serosal side) allows a rapid rise in concentration of transferred substances. A number of adjacent segments of intestine from the same animal may be studied simultaneously. The method was tested with glucose and methionine, both substances being known to be transferred against a concentration gradient (Fisher & Parsons, 1949b; Wiseman, 1953). Aerobically both were transferred against a concentration gradient in this preparation, but no active transference took place anaerobically.
1,142 citations
TL;DR: Dole's titrimetric method for determination of the free fatty acids of plasma has been modified to improve its specificity as mentioned in this paper, which yields results which agree well with those of Gordon's method.
1,026 citations
TL;DR: The evolution of oxygen by illuminated chloroplasts does not involve the intermediate production of H 2 O 2 in a form available to the enzyme catalase, and there is no evidence of a generalized reducing power in plants as part of the photosynthetic mechanism.
805 citations
TL;DR: Dietary incorporation of fermentable, indigestible oligosaccharides, by providing SCFA, lowering pH, and increasing bifidobacteria, may be beneficial in improving gastrointestinal health.
Abstract: Certain indigestible oligosaccharides may benefit gastrointestinal tract health via fermentation and proliferation of desirable bacterial species. The purpose of this study was to elucidate effects of selected oligosaccharides on cecal and fecal short-chain fatty acid (SCFA) concentration, pH, total large bowel wet weight and wall weight, and gut microbiota levels in rats. Fifty male Sprague-Dawley rats were randomly assigned to one of five treatments: 1) control diet; 2) control diet + 5% microcrystalline cellulose (5% CC); 3) control diet + 5% CC + 6% fructooligosaccharides; 4) control diet + 5% CC + 6% oligofructose; or 5) control diet + 5% CC + 6% xylooligosaccharides. The control diet consisted of (dry matter basis) 20% protein, 65% carbohydrate, 10.5% fat, vitamin and mineral mixes. The duration of the study was 14 d. The oligofructose- and fructooligosaccharide-containing diets resulted in higher cecal butyrate concentrations compared with the control, cellulose and xylooligosaccharide diets. Generally, total cecal SCFA pools were higher while pH was lower from ingesting oligosaccharide-containing diets compared with control or cellulose diets. Cecal total weight and wall weight were higher from oligosaccharide consumption, whereas colonic total wet weight was higher for rats consuming xylooligosaccharides compared with other treatments; colon wall weight was unaffected by treatments. Cecal bifidobacteria and total anaerobes were higher whereas total aerobes were lower in rats fed oligosaccharide diets compared with those fed the control diet. Cecal lactobacilli levels were unaffected by treatment. Dietary incorporation of fermentable, indigestible oligosaccharides, by providing SCFA, lowering pH, and increasing bifidobacteria, may be beneficial in improving gastrointestinal health.
727 citations
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TL;DR: These, then, are the primary sources of error peculiar to the two types of photoelectric calorimeter, but superimposed on them is another fault shared equally by instruments of both classes.
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