Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0009443 (cold)
 92,137 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cardiac hypertrophy was induced in rats by daily injections of L-thyroxine (1.0 mg/kg). Regression from hypertrophy was studied 4 days after discontinuing thyroxine. Isolated, Langendorff-perfused hearts were perfused with Krebs-Henseleit buffer, glucose, insulin, and amino acids. To measure protein synthesis, left ventricular tissue was assayed for incorporation of tritiated phenylalanine into protein. Indices of rates of protein degradation were obtained by measuring the release of cold phenylalanine after blocking protein synthesis with cycloheximide. After 3 days of thyroxine (when cardiac growth was maximally increased), the rate of protein synthesis increased by 22% (P less than 0.001). After 1 week, synthesis was 8% greater than control (P less than 0.05), and by 2 weeks (when hypertrophy was stable and the rate of cardiac growth was similar to controls), synthesis had returned to control levels. In hearts regressing from hypertrophy, synthesis was reduced to 68% of control (P less than 0.001). The rate of protein degradation was decreased by 12% (P less than 0.05) after 3 days of thyroxine, but was not different from control at 1 or 2 weeks. During regression, degradation was 12% below control (P less than 0.05). Changes in the release of several amino acids that are synthesized or metabolized in heart (e.g., alanine, glycine, serine) were different from changes in phenylalanine release. In conclusion thyroxine-induced cardiac hypertrophy and regression are accompanied by changes in protein synthesis and degradation, and amino acid metabolism. The predominant change in hypertrophy is increased protein synthesis with a minor contribution from reduced degradation. Regression of hypertrophy is accompanied by decreased synthesis, not increased degradation.
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PMID:Synthesis and degradation of myocardial protein during the development and regression of thyroxine-induced cardiac hypertrophy in rats. 15 66

Measurements of total body oxygen consumption, visceral and hepatic blood flow, oxygen consumption, exchanges of amino acids, lactate, pyruvate and glucose were made on sheep fed 3--6 h or 21 h before the experiment and exposed for 3 h to a neutral environment (15 degrees C) or a cold environment (0.5 to 4 degrees C with clipped coat and wind speed 2 m.s-1). Recent feeding significantly increasedd the total oxygen consumption and the oxygen consumption of the viscera and liver. No general release of amino acids from the viscera or uptake by the liver after feeding was detected although the arterial plasma concentration of essential amino acids did increase significantly after feeding. The plasma concentration of most non-essential amino acids also increased except that of glycine, which decreased significantly. Cold exposure increased the total oxygen consumption and reduced the respiratory quotient significantly. Release of amino acids from the viscera was stimulated by cold exposure. There was a variable increase in the hepatic uptake of lactate and alanine when the sheep were fasted and cold-exposed. The liver's glucose output doubled and the blood (arterial) glucose concentration significantly increased in the cold.
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PMID:Acute cold exposure and the metabolism of glucose and some of its precursors in the liver of the fed and fasted sheep. 24 36

Among temperature resistant revertants of a temperature sensitive E. Coli alanyl-tRNA synthetase mutant a strain was found which contains an alanyl-tRNA synthetase with an additional mutation in the structural gene of the enzyme. This mutant enzyme has a 9 or 38 fold decreased Km value for alanine compared to that of the thermolabile parental enzyme or to wild-type enzyme, respectively. The alaS gene maps just counterclockwise from recA on the E. coli map (94% cotransduction frequency). It appears that the enzyme's increased affinity for alanine is the mechanism of suppressing the temperature sensitive character of the cell. In addition, some cold-sensitive temperature resistant revertants were found, where the cold-sensitive character mapped near strA. Presumably they are due to changes in ribosomal proteins as characterized by Ruffler et al. (1974).
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PMID:Suppression of a defective alanyl-tRNA synthetase in Escherichia coli: a compensatory mutation to high alanine affinity. 34 Sep 3

Minicells produced by Bacillus subtilis CU403 (divIVB1) are capable of mucopeptide biosynthesis as shown by the incorporation of L-alanine, D-alanine, and N-acetylglucosamine into trichloroacetic acid-precipitable material, which can be degraded to trichloroacetic acid-soluble material by lysozyme digestion. Incorporation of the precursors is sensitive to vancomycin and D-cycloserine and insensitive to chloramphenicol. Penicillin inhibits the incorporation of D- and L-alanine N-acetylglucosamine at concentrations in excess of 10 mug of penicillin per ml; however, minicells are insensitive to penicillin-induced lysis. The material synthesized in minicells from N-acetylglucosamine is not subject to turnover during a subsequent 6-h incubation period. [2-3H]glycerol is converted to a cold trichloroacetic acid-precipitable form by minicells. This synthesis is not inhibited by vancomycin, penicillin, D-cycloserine, or chloramphenicol. Fractionation of the material synthesized from glycerol into hot trichloroacetic acid-soluble material and chloroform/methanol-extractable material indicates that minicells convert glycerol into teichoic acid and lipid.
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PMID:Synthesis of cell envelope components by anucleate cells (minicells) of Bacillus subtilis. 40 71

The taste receptor membrane fraction (Fraction P2) was prepared from a homogenate of the taste tissue of the channel catfish Ictalurus punctatus. This included the rostral, dorsal, and dorsolateral surfaces of the catfish in addition to those of the barbels. The yield of Fraction P2 is 4-7 mg protein from an individual fish, with a purification averaging 8- to 15-fold over that of the crude whole homogenate and essentially quantitative recovery of binding activity in Fraction P2. Treatment of Fraction P2 in vitro with a high concentration of the taste stimulus molecule L-alanine led to a several-fold enhancement of binding activity. Enhancement of the binding of 3H L-alanine was observed after treatment with unlabeled 10 mM L-alanine and removal of the L-alanine by washing. Enhancement occurred whether the preparation was stored frozen (-65 degrees C) for an extended period in the presence of the L-alanine, or merely exposed to it in the cold without freezing. D-Alanine enhanced the binding activity of 3H L-alanine to about 60% of the level induced by L-alanine. Nonspecific binding of 3H L-alanine was unaffected by the treatment. Scatchard analyses of saturation curves for binding of 3H L-alanine to freshly prepared Fraction P2 and to L-alanine-treated Fraction P2 revealed no change in the KD value, but a several-fold increase occurred in the amount bound. Binding activity is operationally defined. Because the enhancement observed here is reminiscent of an increase in transport due to a countertransport effect, further studies were carried out to examine whether the phenomenon reflects transport or true binding. The measured binding was not increased in the presence of Na+, indicating that it is not due to an Na+-coupled transport of L-alanine. When Fraction P2 was preloaded with L-alanine (10(-6)--10(-2) M) prior to assay, no stimulation of binding was observed; instead, binding decreased. This result is consistent with a true binding phenomenon but not with a carrier-mediated transport process to explain the enhancement phenomenon. Binding assays carried out over a range of osmolarities revealed decreased binding at high osmotic strengths, suggesting that a significant portion of the ligand might be contained in vesicles. It is postulated that "hidden" or "buried" receptor sites exist in the Fraction P2 as isolated, and that these are exposed upon perturbation of the membrane structure by a high ligand concentration.
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PMID:Biochemical studies of taste sensation. VII. Enhancement of taste stimulus binding to a catfish taste receptor preparation by prior exposure to the stimulus. 45 36

The influence of synthetic gonadotropin-releasing hormone (GnRH) on incorporation of glucosamine and amino acids into LH and total protein was investigated. Rat pituitaries were incubated in vitro with radioactive precursors for 4 h at 37 C. Labeled LH was isolated by immunoprecipitation with specific anti-LH-beta serum. Total LH in the medium and pituitary glands was measured by radioimmunoassay. GnRH significantly stimulated incorporation of [3H]glucosamine into LH in pituitaries from immature male, intact female, and ovariectomized rats. Pituitaries from ovariectomized rats synthesized more [3H]glucosamine-labeled LH than those from intact adult rats. GnRH enhanced release of [3H]glucosamine-LH into medium in pituitaries of both adult intact and ovariectomized rats. The response to GnRH was greatly reduced when pituitaries were exposed to cold shock before the 4 h incorporation period. In contrast to its effect on incorporation of [3H]glucosamine into LH, GnRH had either no or little effect, depending on experimental conditions, on uptake of [3H]glucosamine by pituitaries. Incorporation of [3H]glucosamine into total protein was not affected by GnRH treatment. GnRH increased release of either [3H]leucine- or [3H]alanine-labeled LH into medium, but had no significant effect on incorporation of labeled amino acids into total LH in the system. GnRH modified neither uptake nor incorporation of amino acids into total protein. GnRH significantly stimulated the release of cold LH into medium under all conditions, but the total amount of immunoassayable LH in the system was not detectably modified by GnRH treatment.
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PMID:Effects of synthetic gonadotropin-releasing hormone on incorporation of radioactive glucosamine and amino acids into luteinizing hormone and total protein by rat pituitaries in vitro. 76 13

Pyruvate kinase (PK-II) isoenzyme from rabbit adrenal cortex was isolated by chromatography on DEAE-cellulose during long-term incubation in the cold. The enzyme is resistant to fructose-1,6-diphosphate (FDP) and L-alanine. Dithiotreitol and preincubation for 10 min. at 30 degrees C did not change the resistance of the enzyme to these factors. Preincubation for 30 min. at 30 degrees C in the presence of EDTA (3.3 mM) converted the enzyme into the FDP-sensitive form, the dependency curve of the initial reaction rate on the concentration of phosphoenolpyruvate being S-form. Sucrose and dithiotreitol contributed the isolation of PK-II from rabbit adrenal cortex in the form having a higher degree of the interaction of active sites.
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PMID:[2 interconvertible forms of L type pyruvate kinase from the rabbit adrenal cortex]. 81 84

Carbohydrates roughly constitute 15 p. 100 of the dry matter of Sirulina. They are extracted after complete delipidation, by successive exhaustions: first with ethanol of decreasing title, then with cold water slightly acidified by chlorhydric acid in order to drain out the calcium of the phytate; then by neutral boiling water; at last by alkaline or acidic warm solutions. After neutralization, suitable defecation and concentration, carbohydrates are either purified by a slow cristalization or hydrolyzed and analysed by usual techniques of chromatography on paper or on column of borated resins. Glucose, levulose, sucrose, glycerol and several polyols are so detected. They are in small amounts and of little nutritional interest. There is no trehalose. The carbohydrate storage products are mainly a glucosan and a rhamnosan, both containing glucosamine. There is about 2 p. 100 of the glucosan and 10 p. 100 of the rhamnosan, the composition of which are, in molar ratio: (see text). More or less phosphated cyclitols constitute, together with a small amount of glycogen, the rest of the metabolisable part. The cell-walls which could not be perfectly purified were degraded either by HC1 or by enzymes (pronase, neuraminidase). So have been found glucosamine and muramic acid, associated with peptides rich in glycine, serine, alanine, glutamic acid. These results joined to the presence, formerly signaled, of a rhamnosan, reveal a relationship between Spirulina and some Gram(+) bacteria. It is a fact that the celle-walls of Spirulina actually, though weakly, take the Gram coloration. To conclude, Spirulina presents some alimental interest.
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PMID:[Carbohydrates synthesized by the spirulines]. 82 97

It has been demonstrated in several diving vertebrates that succinate, a component of the Krebs cycle, accumulates in blood during breath-hold dives. The production of succinate is thought to result from amino acid catabolism. Our purpose was to determine whether succinate accumulation occurs in man during muscular activity requiring anaerobic energy contribution. Experiments using an endurance athlete included apneic work on an underwater ergometer and treadmill running to exhaustion. During 1 min breath-hold "dives" in cold water while exercising at a work rate equivalent to 62% of VO2max, venous succinate increased from 42 mumoles/l (M X 10(-6)) at rest to 125 M X 10(-6). The treadmill run elicited VO2max and increased succinate from a similar resting value to 93 M X 10(-6). Increases in alanine, lactate, and pyruvate were observed for both types of exercise. The findings confirm that succinate accumulation also occurs in man. It was suggested that amino acid catabolism may provide a source of anaerobic energy production in addition to glycolysis. However, the importance of the proposed energy pathway remains to be quantified.
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PMID:Succinate accumulation in man during exercise. 97 51

A protein which binds both glutamate (K-D = 0.8 muM) and aspartate (K-D = 1.2 muM) has been purified to homogeneity (290-fold) from the periplasmic fraction released from Escherichia coli W3092 by the cold osmotic shock procedure. The apparent molecular weight of the glutamate-aspartate binding protein is approximately 31,000 as judged by gel electrophoresis, gel filtration, and sedimentation equilibrium centrifugation; and the protein has a pI of 9.69. This protein contains 2 half-cystine residues and is dependent on a dithiothreitol-sensitive component for renaturation to an active conformation following urea or guanidine treatment. Of the natural amino acids only the L isomers of glutamate, aspartate, glutamine, asparagine, and alanine were inhibitors of either [C]glutamate or [14C]aspartate binding and the inhibitions were competitive. Only one binding site is indicated per molecule of protein. Antibody prepared against the glutamate-asparate binding protein does not cross-react with purified glutamine binding protein or any other component of osmotic shock fluid. The antibody does cross-react with osmotic shock fluids obtained from E. coli strains B and W and Salmonella typhimurium OT2. The glutamate-aspartate binding protein-antibody complex does not bind either glutamate or aspartate. The protein may be similar to the glutamate binding activity detected in the periplasmic fraction released from E. coli strain B (Miner, K.M., and Frank, L. (1974) J. Bacteriol. 117, 1093-1098) and strain K12 CS (Barash, H., and Halpern, Y.S. (1971) Biochem. Biophys. Res. Commun. 45, 681-688). This protein appears to function in the transport of glutamate by E. coli strain W cultured in minimal medium with succinate as the carbon source (Willis, R.C., and Furlong, C.E. (1975) J. Biol. Chem. 250, 2581-2586.
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PMID:Purification and properties of a periplasmic glutamate-aspartate binding protein from Escherichia coli K12 strain W3092. 109 35


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