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

Tetrahymena pyriformis were grown in proteose-peptone medium and then washed and incubated in a dilute salt solution for one hour. The cells were then discarded and the lysosomal hydrolases that had been secreted were subjected to DEAE cellulose column chromatography. At least three isoenzymes of acid phosphatase, three of acid protease, and two of beta-N-acetylhexoseaminidase were found, as well as single peaks of alpha-mannosidase, beta-galactosidase, and beta-fucosidase. The latter two activities were not resolved by the DEAE column and could not be separated in a second chromatographic step on CM-cellulose. Cells were also grown under identical conditions and homogenized in 0.25 M sucrose in order to allow comparison of some of the intracellular lysosomal hydrolases with their secreted counterparts. Two lysosomal populations were resolved by sucrose density gradient sedimentation, a heavy lysosomal fraction, contered at a density of about 1.25 gm/cm3, and a light lysosomal fraction, centered at a density of about 1.16 gm/cm3. These two populations differed in that the light lysosomes did not appear to contain significant amounts of beta-fucosidase, beta-galactosidase, or acid protease, whereas all six of the hydrolase activities studied were present in the heavy lysosomes. The light lysosomal peak occurred in cells grown to transition phase, but was markedly reduced in cells from cultures grown to stationary phase. In addition to these two fractions a third very light particle, containing only alpha-mannosidase activity, was detected just inside the gradient. Measurements were made of the effect of heat (10 minutes at 66 degrees) and of a change in pH from 4.5 (standard assay condition) to 6.0 on the three acid phosphatases and two beta-N-acetylhexoseaminidase isoenzymes resolved by DEAE column chromatography of the secreted hydrolases and on these hydrolyases in the heavy and light lysosomal fractions on the sucrose gradient. Use of the thermostability and pH criteria permitted computation of the expected properties of the intralysosomal acid phosphatase and hexoseaminidase activities if these consisted of the respective isoenzymes in the proportions secreted. It was found that neither the intralysosomal acid phosphatase nor the intralysosomal hexoseaminidase had the properties expected if they consisted of the secreted mixture of the respective isoenzymes, indicating that modification of some of these isoenzymes may have occurred during the 1-hour starvation period or after secretion.
 ...
PMID:Lysosomal hydrolase secretion by Tetrahymena: a comparison of several intralysosomal enzymes with the isoenzymes released into the medium. 1 Mar 11

Acid phosphatase activity is demonstrated employing p-nitrophenyl phosphate as substrate and lead acetate as coupler. The fine structural localization of the enzyme in starved planarian tissues is described. The method is used to pin-point starvation - induced acid phosphatase activity in relation to autophagy and crinophagy in the gland cells; autophagy, autolysis and cell death in parenchymal and gastrodermal cells and basement membrane lysis. Attention is also payed to the demonstration of muscle lysis. The histochemical implications of the method are discussed.
 ...
PMID:Use of the p-nitrophenyl phosphate method for the demonstration of acid phosphatase during starvation and cell autolysis in the planarian Polycelis tenuis Iijima. 5 22

After an initial decrease, the specific activity of Physarum polycephalum acid phosphomonoesterase increases during the growth of the organism in an axenic medium. This increase is independent of the inorganic phosphate concentration in the culture medium. The specific activity of inorganic alkaline pyrophosphatase remains constant during the growth and is not modified by a high extracellular concentration of orthophosphate. During starvation in a non nutritive saline medium, the increase of acid phosphatase activity is immediate whereas pyrophosphatase activity remnins constant.
 ...
PMID:Studies on the activities of an acid phosphomonoesterase and an alkaline pyrophosphatase during the growth of Physarum polycephalum. 7 Oct 89

The ultrastructure of the mid-gut cells of female Nasonia vitripennis is described. The mid-gut consists of a uniform, single-cell epithelium. The cells of different gut regions were analysed using morphometric techniques in order to determine any differences in the components. The structure of the cells is described in the unfed animal, and after varying periods of feeding on host body-fluids. Tissues were sampled after 12 h and 24 h of feeding on host body-fluids and after 24 h feeding/24 h starvation. The cells were found to be complex and contain an organelle component that allows solute-transport and extensive lipid synthesis. A limited cytochemical analysis involving the lysosomal marker enzyme-acid phosphatase--and the respiratory enzyme--cytochrome oxidase was carried out.
 ...
PMID:The ultrastructure of the mid-gut cells of Nasonia vitripennis (Walker) (Hymenoptera, Pteromalidae). 18 30

The regulation of three Salmonella typhimurium phosphatases in reponse to different nutritional limitations has been studied. Two enzymes, an acid hexose phosphatase (EC 3.1.3.2) and a cyclic phosphodiesterase (EC 3.1.4.d), appear to be regulated by the cyclic adenosine 3' ,5'-monophosphate (AMP) catabolite repression system. Levels of these enzymes increased in cells grown on poor carbon sources but not in cells grown on poor nitrogen or phosphorus sources. Mutants lacking adenyl cyclase did not produce elevated levels of these enzymes in response to carbon limitation unless cyclic AMP was supplied. Mutants lacking the cyclic AMP receptor protein did not produce elevated levels of these enzymes in response to carbon limitation regardless of the presence of cyclic AMP. Since no specific induction of either enzyme could be demonstrated, these enzymes appear to be controlled solely by the cyclic AMP system. Nonspecific acid phsphatase activity (EC 3.1.3.2) increased in response to carbon, nitrogen, phosphorus, or sulfur limitation. The extent of the increase depended on growth rate, with slower growth rates favoring greater increases, and on the type of limitation. Limitation for either carbon or phosphorus resulted in maximum increases, whereas severe limitation of Mg2+ caused only a slight increase. The increase in nonspecific acid phosphatase during carbon limitation was apparently not mediated by the catabolite repression system since mutants lacking adenyl cyclase or the cyclic AMP receptor protein still produced elevated levels of this enzyme during carbon starvation. Nor did the increase during phosphorus limitation appear to be mediated by the alkaline phosphatase regulatory system. A strain of Salmonella bearing a chromosomal mutation, which caused constitutive production of alkaline phosphatase (introduced by an episome from Escherichia coli), did not have constitutive levels of nonspecific acid phosphatase.
 ...
PMID:Regulation of two phosphatases and a cyclic phosphodiesterase of Salmonella typhimurium. 19 13

Comprehensive investigations were carried out for establishing the biological and nutritional value of low erucic-acid rapeseed oil from a variety of rape called Janpol selected in Poland. The pathophysiological effects of Janpol rapeseed oil were observed after giving it as the only source of fat in the diet or added in different proportions to other edible fats. In all cases the total amount of fat in the diet was 20 p. 100 kcal. The investigations were carried out on 78 young male Wistar rats aged 25 days at the beginning of the experiment. The rats were divided into 7 groups and they were given diets containing: 1) soybean oil; 2) mixed fats; 3) rapeseed oil of high erucic-acid content; 4) mixed fats containing 25 p. 100 of Janpol rapeseed oil; 5) mixed fats with 50 p. 100 of Janpol rapeseed oil; 6) mixed fats with 75 p. 100 of Janpol rapeseed oil; 7) Janpol rapeseed oil only. The experiment lasted 3 months. After its completion the rats were decapitated after 18 hours of starvation. The investigation s included : determination of weight gain, determination of the weight of selected organs (liver-lungs, heart, kidneys, testes, spleen), determination of alkaline phosphatase and pseudocholinesterase activity in the serum, determination of triglycerides and cholesterol in the serum, tests for adrenocortical function, histo-chemical investigations of the liver (alkaline and acid phosphatase, adenosine triphosphatase, fatty infiltration of the liver), macroscopic and microscopic anatomopathological examinations. The authors found the Janpol rapeseed oil caused less pronounced changes in the determined indices of the biological and nutritional evaluation as compared with high-erucic-acid rapeseed oil. Janpol repeseed oil given to experimental animals mixed with other fats in proportions of 25 p. 100 and 50 p. 100 of all fats in the diet, that is 5 p. 100 and 10 p. 100 kcal in the diet derived from Janpol oil gave in most determinations of the investigated parameters results very similar to those observed in animals receiving soybean oil. The results of these investigations show that Janpol rapesed oil can be used for nutrition of man in amounts not exceeding 10 p. 100 of the total caloric content of food.
 ...
PMID:[Nutritional and biological experiences on low-erucic acid rapeseed oil "Janpol". Studies on rats after ingestion of "Janpol" oil and other edible fats]. 22 Sep

A cyclic nucleotide-binding phosphohydrolase that possesses both a phosphomonoesterase and a phosphodiesterase catalytic function has been partially purified from Aspergillus nidulans. The enzyme hydrolyzes both p-nitrophenylphosphate and bis-(p-nitrophenyl)-phosphate. o'-Nucleoside monophosphates are the best physiological phosphomonesterase substrates but 5'- and 2'-nucleoside monophosphates are also hydrolyzed. The enzyme catalyzes the hydrolysis of adenosine 5'-triphosphate, adenosine 5'-diphosphate, and 2',3'- and 3'5'-cyclic nucleotides, but not of ribonucleic acid, deoxyribonucleic acid, or nicotinamide adenine dinucleotide. The enzyme has acid pH optima and is not activated by divalent cations. Nucleosides and nucleotides inhibit the enzyme. Cyclic nucleotides are competitive inhibitors of the phosphodiesterase-phosphomonoesterase. The enzyme can occur extracellularly. The phosphodiesterase-phosphomonoesterase is present at high levels in nitrogen-starved mycelium, and it is strongly repressed during growth in media containing ammonium or glutamine and weakly repressed during growth in glutamate-containing medium. Experiments with various area mutants show that this regulatory gene is involved in the control of the enzyme. No evidence for regulation of the enzyme by carbon or phosphorus starvation has been found.
 ...
PMID:Enzymology and genetic regulation of a cyclic nucleotide-binding phosphodiesterase-phosphomonoesterase from Aspergillus nidulans. 24 43

The effect of exogenous orthophosphate and mutations in regulatory genes of alkaline phosphatase on the level of nonspecific acid phosphatase was studied. The level of this enzyme as well as the level of alkaline phosphatase were shown to be regulated by exogenous orthophosphate being derepressed under phosphate starvation. The derepression of acid phosphatase is accompanied by more rapid secretion of enzyme from membranes to soluble fraction. Mutations in all the four regulatory genes decrease the level of enzyme in cells. Genes phoR and phoS, participating in regulation of alkaline phosphatase, are required for the derepression of acid phosphatase under the conditions of phosphate starvation.
 ...
PMID:[Interrelationship between metabolic and genetic regulation of alkaline and acid phosphatases in E. coli cells]. 36 75

The rate kinetics of growth and acid phosphate formation in the batch culture of Saccharomyces carlsbergensis LAM 1068 was studied under varying degrees of phosphate limitation. The mathematical model that was developed is concerned with the time lag for exponential growth, the biphasic growth on a substrate (glucose) and its product (ethanol), sustained growth on conservative phosphate, and the derepression of acid phosphatase. The numerical calculations using appropriate parametric constants successfully described the variation in the cell mass, glucose, ethanol, and inorganic phosphate concentrations, and the enzyme activity of acid phosphatase during aerobic growth of S. carlsbergensis under five different conditions of phosphate starvation. A simulation study revealed that the optimum initial phosphate concentration in the medium giving a high productivity of acid phosphatase was 2.0 mg phosphorus/g glucose liter.
 ...
PMID:Mathematical model of cell growth and phosphatase biosynthesis in Saccharomyces carlsbergensis under phosphate limitation. 42 66

The activity of glycolysis and hexose monophosphate shunt decreases while the activity of some oxydative enzymes and acid phosphatase increases in the anterior pituitary of adult female rats during starvation. The alterations depend on the severity of starvation. The polypeptide hormone production also decreases. A close relationship exists between the metabolic activity of the gland and its endocrine function.
 ...
PMID:Activity alterations of metabolic enzymes in the anterior pituitary of female rats during acute and chronic starvation, as well as after refeeding. 63 63


1 2 3 4 5 6 7 8 9 10 Next >>