Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An intracellular form of calcium ion-dependent transglutaminase (R-glutaminylpeptide:amine gamma-glutaminyltransferase, EC 2.3.2.13) was purified 818-fold to apparent homogeneity from acetone powder preparations of spherules of the acellular slime mold Physarum polycephalum. The enzyme was purified by combined methods of precipitation with 15% (wt/vol) polyethylene glycol, DEAE-cellulose chromatography, and isoelectric focusing in a pH 5 to 7 gradient. The isoelectric point of the enzyme was 6.1. The molecular mass of the denatured enzyme was estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be 39.6 kDa. A molecular weight of 77,000 was found by gel filtration of the native enzyme on a Superose 12 fast protein liquid chromatography column, indicating that the native functional protein is a dimer. The purified transglutaminase catalyzed the incorporation of [14C]putrescine into protein substrates including casein, N,N'-dimethylcasein, actin purified from P. polycephalum, and actin purified from bovine muscle. Actin was the preferred substrate for the enzyme, both as a purified protein and in crude extracts prepared from P. polycephalum. With N,N'-dimethylcasein as the amine acceptor substrate, [14C]putrescine, [14C]spermidine, and [14C]spermine were all effective amine donor substrates with Km values of 49, 21.4, and 31.7 microM, respectively. All three of these polyamines demonstrated strong substrate inhibition of the enzyme activity between 100 and 200 microM. Upon starvation induced by depletion of a carbon source for growth, the specific activity of this enzyme increased sixfold during the differentiation of P. polycephalum microplasmodia to spherules. This suggests a role for transglutaminase in the construction of spherules, which have the capacity to survive starvation and dessication.
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PMID:Purification and partial characterization of transglutaminase from Physarum polycephalum. 134 44

To compare the tropic effect of different dietary nutrients on mucosal adaptation in the jejunum and ileum, adult rats were submitted to a 96-h period of starvation and refed isocaloric liquid diets (1.5 kcal ml-1) containing either protein (casein), carbohydrate (starch) or lipids. In the jejunum, 4 days of starvation caused mucosal hypoplasia, villus and crypt shortening and a decrease in the total activity of disaccharidases with the exception of lactase which was markedly enhanced. In contrast, mucosal hypoplasia was incomplete in the ileum which exhibited an increase in crypt depth and in the specific and total activities of disaccharidases and of aminopeptidase. Compared with protein and carbohydrates, lipids exerted the strongest stimulatory effect for mucosal regeneration. In the jejunum as well as in the ileum, mucosal mass parameters, villus length, crypt depth and lactase activity did reverse towards their initial value within 1-3 days of refeeding lipids, even though the animals received only one-third of their normal daily caloric intake. Our results indicate that the pattern of response to fasting differs between the proximal and distal small intestine, and that the intestinal changes induced by starvation are rapidly reversed by refeeding small amounts of a diet rich in fat.
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PMID:Refeeding after starvation in the rat: comparative effects of lipids, proteins and carbohydrates on jejunal and ileal mucosal adaptation. 212 4

The three yolk proteins of Drosophila melanogaster begin to be synthesized at eclosion. Transcription of the genes is regulated by the genes tra, tra-2 and dsx and also by the insect hormones, juvenile hormone and 20-hydroxyecdysone. We show that there is yet another level of control which is dependent upon feeding. Females that are starved from eclosion show a basal level of yolk protein gene transcription, which is rapidly increased when a complete diet is supplied. We show that the effect is not due to incorrect development of the fat body and is unlikely to be solely due to a general effect on protein synthesis. Later in development, cessation of feeding leads to selective inhibition of yolk protein synthesis and hence egg production. The effects of starvation can be partially overcome by 20-hydroxyecdysone, juvenile hormone, casein, amino acid mix or sucrose, but only a complete medium or live yeast brings about total recovery. Using yp1-Adh fusions (fusions of the promoter region of yp1 to the structural gene for Adh), the DNA sequence required for this diet-enhanced transcription has been located within an 890 bp fragment upstream of the yp1 gene. The insect hormones do not operate on this same DNA fragment.
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PMID:Dietary components modulate yolk protein gene transcription in Drosophila melanogaster. 246 49

Argininosuccinate synthetase and argininosuccinate lyase catalyze the synthesis of arginine from citrulline in kidney and also serve as components of the urea cycle in liver of ureotelic animals. Dietary and hormonal regulation of mRNAs encoding these enzymes have been well studied in liver but not in kidney. Messenger RNAs for these enzymes are localized within the renal cortex. Starvation and extreme variations in dietary protein content (0% vs 60% casein) produced 2.6- to 3.5-fold increases in mRNA abundance for these two enzymes in rat kidney. Argininosuccinate lyase mRNA was not induced by dibutyryl cAMP, dexamethasone, or a combination of the two agents. In contrast, argininosuccinate synthetase mRNA was induced 2-fold by dibutyryl cAMP but was unresponsive to dexamethasone. Thus, diet and hormones regulate levels of these mRNAs in rat kidney, but the responses are both qualitatively and quantitatively distinct from the responses previously reported for rat liver.
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PMID:Nutritional and hormonal regulation of mRNA abundance for arginine biosynthetic enzymes in kidney. 254 41

The established relationship between erythropoietic activity and body growth rate in the polycythemic growing rat could be the result of either an erythropoietin (EPO)-dependent or an EPO-independent operating mechanism. The present study was thus undertaken to elucidate the nature of the aforementioned mechanism by assessing the ratio between plasma immunoreactive EPO (iEPO) concentration and erythropoietic activity in young hypertransfused rats for different body growth rates. Red blood cell (RBC)-59Fe uptake was about 75% in 21-day-old rats; it rapidly decreased with time when the animals were placed on a protein-free diet, approaching a level of about 1% by the 10th day of protein starvation. Over the same period plasma iEPO decreased from 55 mU/ml to 7 mU/ml. Body growth rate was 0. Following this "protein depletion period" the rats received diets containing different amounts of casein ("protein repletion period") added isocalorically to the protein-free diet to elicit a rise in body growth rate. Statistically significant relationships (p less than 0.001) were found between dietary casein concentration and body growth rate (r = 0.991), dietary casein concentration and RBC-59Fe uptake (r = 0.991), dietary casein concentration and plasma iEPO level (r = 0.992), body growth rate and RBC-59Fe (r = 0.986), and body growth rate and plasma iEPO level (r = 0.994) in hypertransfused polycythemic rats during the protein repletion period. These findings suggest that the correlation between erythropoietic activity and growth rate in the growing rat is the result of an erythropoietin-dependent operating mechanism, which appears to be independent of the ratio tissue oxygen supply/tissue oxygen demand.
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PMID:Correlation between erythropoietic activity and body growth rate in hypertransfused polycythemic growing rats as the result of an erythropoietin-dependent operating mechanism. 291 44

The ATP-binding component (Component II, hereafter referred to as ClpA) of a two-component, ATP-dependent protease from Escherichia coli has been purified to homogeneity. ClpA is a protein with subunit Mr 81,000. It has an intrinsic ATPase activity and activates degradation of protein substrates only in the presence of a second component (Component I, hereafter referred to as ClpP), Mg2+, and ATP. The amount of ClpA varies by less than a factor of 2 in cells grown in different media and at temperatures from 30 to 42 degrees C. ClpA does not appear to be a heat-shock protein since its synthesis is not dependent on htpR. Antibodies against purified ClpA were used to identify lambda transducing phage bearing the clpA gene. The cloned gene contains a DNA sequence expected to code for the first 28 amino acids of ClpA, which were determined by protein sequencing of purified ClpA. The clpA gene in the phage was mutated by insertion of delta kan defective transposons and the mutations were transferred to E. coli by homologous recombination. The clpA gene was mapped to 19 min on the E. coli chromosome. Mutant cells with insertions early in the gene produce no ClpA protein detectable in Western blots, and extracts of such mutant cells have no detectable ClpA activity. clpA- mutants grow well under all conditions tested and are not defective in turnover of proteins during nitrogen starvation nor in the turnover of such highly unstable proteins as the lambda proteins O, N, and cII, or the E. coli proteins SulA, RcsA, and glutamate dehydrogenase. The degradation of abnormal canavanine-containing proteins is defective in clpA mutants especially in cells that also have a lon- mutation. Extracts of clpA- lon- cells have ATP-dependent casein degrading activity.
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PMID:The two-component, ATP-dependent Clp protease of Escherichia coli. Purification, cloning, and mutational analysis of the ATP-binding component. 304 6

Muscle glutamine concentration ([GLN]) and protein synthesis rate (Ks) have been examined in vivo in well-fed, protein-deficient, starved, and endotoxemic rats. With protein deficiency (8 or 5% casein diet), [GLN] fell from 7.70 to 5.58 and 3.56 mmol/kg in the 8 and 5% diet groups, with Ks falling from 15.42 to 9.1 and 6.84%/day. Three-day starvation reduced [GLN] and Ks to 2.38 mmol/kg and 5.6%/day, respectively. In all these groups food intakes and insulin were generally well maintained (except in the starved group), whereas free 3,5,3'-triiodothyronine (T3) was depressed in the starved and 5% protein group. The E. coli lipopolysaccharide endotoxin (3 mg/kg) reduced [GLN] to 5.85 and 4.72 mmol/kg and Ks to 10.5 and 9.10%/day in two well-fed groups. Insulin levels were increased, and free T3 levels fell. Combined protein deficiency and endotoxemia further reduced [GLN] and Ks to 1.88 mmol/kg and 4.01%/day, respectively, in the 5% protein rats. Changes in both ribosomal activity (KRNA) and concentration (RNA/protein) contributed to the fall in Ks in malnutrition and endotoxemia, although reductions in the RNA concentration were most marked with protein deficiency and reductions in the KRNA dominated the response to the endotoxin. The changes in [GLN] and Ks were highly correlated as were [GLN] and both KRNA and the RNA concentration, and these relationships were unique to glutamine. These relationships could reflect sensitivity of glutamine transport and protein synthesis to the same regulatory influences, and the particular roles of insulin and T3 are discussed, as well as any direct influence of glutamine on protein synthesis.
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PMID:Relationship between glutamine concentration and protein synthesis in rat skeletal muscle. 313 58

Aluminum (Al) compounds are widely used in drugs and food additives but the toxicity of such compounds is not known in detail except in patients with renal insufficiency (J. W. Coburn and A. C. Alfrey, 1986, Kidney Int. 29, Suppl. 18). In this experiment, toxicity of ingested Al was investigated in relation to nutritional conditions in normal rats having no renal insufficiency. Sucrose, lactose, milk, casein and soy-protein diets were prepared. As the Al source, aluminum chloride (AlCl3) was added to these diets at the level of 2000 micrograms/g (ppm). Male weanling Wistar rats were fed for 67 days without any Al effect on body weight gain. After a half-day starvation they were terminated. The significance of difference resulting from Al treatment was statistically tested between rats consuming diet with or without added Al. Serum Al concentrations did not exceed 20 ng/ml in any of the groups. Tibia Al concentration doubled in rats consuming added Al in every diet but lactose. Liver Al concentration increased significantly in the Sucrose, Milk, and Casein groups compared to each Control group consuming diet without addition of Al. No lactose effect on Al accumulation was observed. With Al treatment, anemia and hypophosphatemia were not observed, but a decrease in tibia weight was observed with every diet. Aluminum-dependent decreases in serum triglyceride (TG) concentration were also observed in all dietary groups, without any effect on serum cholesterol or phospholipid (P-lipid) concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Decrease of serum triglyceride in normal rats fed with 2000 ppm aluminum diet for 67 days. I. Feeding young rats sucrose, lactose, milk, casein or soy-protein diets with addition of aluminum chloride. 339 88

The effects of histamine antagonists, an anticholinergic agent and antacid on gizzard erosion (GE) induced by heated casein-histidine mixture (h-CH), histamine or starvation were examined. Diphenhydramine, an H1-antagonist, had no effect on the GE formation caused by h-CH, but reduced the severity of the lesions induced by histamine and starvation. Cimetidine, an H2-antagonist, blocked completely the formation of the lesions induced by h-CH or histamine but did not prevent starvation-induced GE. Gastric antacid decreased the severity of GE caused by h-CH and histamine. The formation of GE by starvation was blocked by the administration of propantheline bromide or inert solids. The results suggest that the stimulated gastric secretion caused by the H2-activity of h-CH or histamine is largely responsible for the formation of GE. In starvation-induced GE, however, alteration of gastric secretion had no effect on the formation of the lesion as it was caused by the emptiness of the gizzard.
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PMID:Effects of histamine antagonists, an anticholinergic agent and antacid on gizzard erosions in broiler chicks. 356 88

Protein synthesis in the rat mammary gland has been studied using acini isolated from mammary tissue by collagenase digestion. When the acini were incubated with radioactively labeled amino acids, both cellular and milk proteins were synthesized and milk proteins were secreted into the incubation medium. Antisera to the lipogenic enzyme, fatty acid synthase, and the milk proteins, alpha-lactalbumin and the caseins, raised in rabbits, were shown to be specific by analyzing immunoprecipitates on sodium dodecyl sulfate--polyacrylamide gels. The rates of synthesis and secretion of each protein by acini prepared from rats during late gestation and at specific stages of lactation reflect their previously observed concentration in the mammary gland or milk of rats at the corresponding stage of gestation or lactation. Rats were treated according to one of the following regimes between d 7 and 14 of lactation: they were fed a control (20% casein) or a low protein (10% casein) diet ad libitum, they were fed the control diet restricted to 25 g/d (40% of the voluntary intake), they were fed the control diet for 5 d and starved for 48 h or they were treated as in 3 and then refed the control diet ad libitum for 24 h. Food restriction and starvation both resulted in lowered rates of synthesis of all proteins examined compared with either the control or refed animals. Starvation also lowered the rates of secretion of the milk proteins. Consumption of the low protein diet caused a specific decrease in both the rates of synthesis and secretion of alpha-lactalbumin compared with the control rats without affecting the synthesis and secretion of the caseins.
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PMID:Protein synthesis in mammary acini isolated from lactating rats: effect of maternal diet. 358 28


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