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)

1. The enzymic utilization of O-acetyl-l-carnitine other than via carnitine acetyltransferase (EC 2.3.1.7) was investigated in liver homogenates from rats, sheep and dry cows. 2. An enzymic utilization of O-acetyl-l-carnitine via hydrolysis of the ester bond to yield stoicheiometric quantities of acetate and l-carnitine was demonstrated; 0.55, 0.53 and 0.30mumol of acetyl-l-carnitine were utilized/min per g fresh wt. of liver homogenates from rats, sheep and dry cows respectively. 3. The acetylcarnitine hydrolysis activity was not due to a non-specific esterase or non-specific cholinesterase. O-Acetyl-d-carnitine was not utilized. 4. The activity was associated with the enriched outer mitochondrial membrane fraction from rat liver. Isolation of this fraction resulted in an eightfold purification of acetylcarnitine hydrolase activity. 4. The K(m) for this acetylcarnitine utilization was 2mm and 1.5mm for rat and sheep liver homogenates respectively. 6. There was a significant increase in acetylcarnitine hydrolase in rats on starvation and cows on lactation and a significant decrease in sheep that were severely alloxan-diabetic. 7. The physiological role of an acetylcarnitine hydrolase is discussed in relation to coupling with carnitine acetyltransferase for the relief of ;acetyl pressure'.
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PMID:Enzymic hydrolysis of acetylcarnitine in liver from rats, sheep and cows. 0 59

The influence of starving on the activity of enzymes of the rat gastric mucosa was investigated by selected histochemical methods. Beside the conventional methods of enzymatic histochemistry the technique of semipermeable membranes was used in the proof of lysosomal enzymes. Dehydrogenases were proved in aqueous and also in gel media with PMS. During the starvation in the parietal cells a marked increase took place in the activity of acid phosphatase, E-600 resistant esterase, less in beta-glucuronidase. High activity of the lysosomal enzymes in macrophages did not change during starvation. Nor did any changes took place in the activity of alkaline phosphatase in the endothelium of the capillaries. The chief cells in the control and starving animals, in contrast to the human gastric mucosa, did not contain any non-specific esterase. Concerning dehydrogenases, parietal cells with a different activity of these enzymes were observed both in starved and control animals. In the rat gastric mucosa starving induced changes in the activity of the enzymes which mark important organelles of the cells. Thus it is possible to consider the observed histochemical changes as a functional manifestation of morphological damage of cellular structures which are affected during starvation.
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PMID:Histochemical findings in the rat gastric mucosa during starvation. 99 73

Cyclic AMP can profoundly influence the growth and differentiation of neuronal cells in culture. In this study, the relationship between this second messenger signal transduction pathway, cell differentiation, and the expression of a retinoid-responsive, thymosin beta-10 gene was examined. Thymosin beta-10 and cognate mRNA were expressed at high levels in actively proliferating rat B104 neuroblastoma cells cultured in medium containing 10% FCS. These cells were induced to differentiate in the presence of the cAMP analog N6, 2'-O-dibutyryladenosine 3':5'-cyclic monophosphate (Bt2-cAMP) (1 mM) and the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX) (100 microM). Expression of thymosin beta-10 mRNA was markedly inhibited (greater than 90% and 70%, respectively) by these compounds. Addition of sodium butyrate (NaB, 1 mM) indicated that at least part of the inhibitory actions of Bt2-cAMP were due to esterase-induced release of butyrate from this compound. Adenosine (50 microM), a metabolic precursor to endogenous cyclic AMP, also inhibited accumulation of thymosin beta-10 mRNA (to less than 70% of control levels). The inhibitory action of Bt2-cAMP upon thymosin beta-10 mRNA levels was time dependent; levels were inhibited by greater than 50% 24 hours after addition of the cAMP analog and by greater than 90% after 72 hours. Serum starvation (0.2% FCS for seven days) provoked a marked increase in neurite out-growth; this morphological change was also accompanied by a modest inhibition of thymosin beta-10 mRNA accumulation. These findings together with previous observations imply that both cyclic AMP-dependent and retinoid-responsive mechanisms coordinate thymosin beta-10 gene expression during neuroembryogenesis.
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PMID:Influence of cyclic AMP and serum factors upon expression of a retinoid-responsive gene in neuroblastoma cells. 137 94

To depolymerize plant pectin, the phytopathogenic enterobacterium Erwinia chrysanthemi produces a series of enzymes which include a pectin-methyl-esterase encoded by the pem gene and five isoenzymes of pectate lyases encoded by the five genes pelA, pelB, pelC, pelD, and pelE. We have constructed transcriptional fusions between the pectinase gene promoters and the uidA gene, encoding beta-glucuronidase, to study the regulation of these E. chrysanthemi pectinase genes individually. The transcription of the pectinase genes is dependent on many environmental conditions. All the fusions were induced by pectic catabolic products and responded, to different degrees, to growth phase, catabolite repression, temperature, and nitrogen starvation. Transcription of pelA, pelD, and pelE was also increased in anaerobic growth conditions. High osmolarity of the culture medium increased expression of pelE but decreased that of pelD; the other pectinase genes were not affected. The level of expression of each gene was different. Transcription of pelA was very low under all growth conditions. The expression of the pelB, pelC, and pem genes was intermediate. The pelE gene had a high basal level of expression. Expression of pelD was generally the most affected by changes in culture conditions and showed a low basal level but very high induced levels. These differences in the expression of the pectinase genes of E. chrysanthemi 3937 presumably reflect their role during infection of plants, because the degradation of pectic polymers of the plant cell walls is the main determinant of tissue maceration caused by soft rot erwiniae.
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PMID:Environmental conditions affect transcription of the pectinase genes of Erwinia chrysanthemi 3937. 144 47

Macrophages consume cystine and generate approximately equivalent amounts of acid-soluble thiol. Stimulation of macrophages with bacterial lipopolysaccharide (LPS) or tumor necrosis factor (TNF) strongly augments the amount of thiol released into the culture supernatant. Cysteine constitutes most of the acid-soluble thiol. The intracellular glutathione level and the DNA synthesis activity in mitogenically stimulated lymphocytes are strongly increased by either exogenously added cysteine, or (syngeneic) macrophages. This cysteine dependency is observed even in the presence of relatively high extracellular cystine concentration as they occur in the blood plasma. The extracellular cysteine concentration also has a strong influence on the intracellular glutathione concentration, viability, and DNA synthesis of cycling T cell clones. Moreover, the cysteine concentration in the culture medium on Day 3 and Day 4 of a 5-day allogeneic mixed lymphocyte culture (i.e., in the late phase of incubation) has a strong influence on the generation of cytotoxic T cell activity, indicating that regulatory effects of cysteine are not restricted to the early phase of the blastogenic response. The inhibitory effect of cysteine starvation on the DNA synthesis of the T cell clones and on the activation of cytotoxic T lymphocytes can be explained essentially by the depletion of intracellular glutathione, since similar effects are observed after treatment with buthionine sulfoximine (BSO), a specific inhibitor of the glutathione biosynthesis. BSO has practically no influence, however, on the N alpha-benzyloxycarbonyl Ne-t-butyloxycarbonyl-L-lysine-thiobenzyl-ester (BLT)-esterase activity and hemolytic activity of the cell lysates from cytotoxic T cells against sheep red blood cells (perforin activity). Taken together, our experiments indicate that cysteine has a regulatory role in the immune system analogous to the hormone-like lymphokines and cytokines. It is released by macrophages at a variable and regulated rate and regulates immunologically relevant functions of lymphocytes in the vicinity.
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PMID:Macrophages regulate intracellular glutathione levels of lymphocytes. Evidence for an immunoregulatory role of cysteine. 236 41

CULTURED KB CELLS (DERIVED FROM A HUMAN ORAL CARCINOMA) GROWN IN MONOLAYERS WERE INJURED BY ONE OF THREE AGENTS: starvation by arginine deprivation or treatment with high doses of either ultraviolet radiation or x-radiation. The different agents produced changes in nucleolar structure and varying accumulations of triglyceride and glycogen. All three agents produced an increase in number and size of lysosomes. These were studied in acid phosphatase preparations, viewed by both light and electron microscopy, and, occasionally, in vital dye, esterase, and aryl sulfatase preparations. Ultrastructurally, alterations in lysosomes suggested that "residual bodies" developed in a variety of ways, i.e., from the endoplasmic reticulum, multivesicular bodies, or autophagic vacuoles. Following all three agents the endoplasmic reticulum assumed the form of "rough" or "smooth" whorls, and, after two of the agents, arginine deprivation or ultraviolet radiation, it acquired cytochemically demonstrable acid phosphatase activity. Near connections between the endoplasmic reticulum and lysosomes raise the possibility that in KB cells, at least when injured, the endoplasmic reticulum is involved in the formation of lysosomes and the transport of acid phosphatase to them.
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PMID:Effects of arginine deprivation, ultraviolet radiation, and x-radiation on cultured KB cells. A cytochemical and ultrastructural study. 532 75

Murine neuroblastoma cells have been widely used as a model system for neuronal cells as they can be induced to differentiate in culture by various stimuli, such as dibutyryl cyclic AMP (dbcAMP), prostaglandin, and serum starvation. The cells respond with assembly of microtubules, leading to neurite outgrowth, with increased activity of neuronal-specific enzymes, tyrosine hydroxylase, choline acetyltransferase and acetylcholine-esterase, and synthesis of neurotransmitters. The differentiated cells lose tumorigenicity. Cell-to-substratum adhesion is evidently crucial for neurone extension in vitro. Neurite outgrowth is induced by treatments that increase cell-to-substratum adhesion in some neuronal cell cultures. We have now identified the major high molecular weight proteins synthesized and secreted by murine C1300 neuroblastoma cells as fibronectin, laminin and type IV procollagen, of which the latter two were also found to be deposited in pericellular matrix form.
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PMID:Basal lamina glycoproteins are produced by neuroblastoma cells. 743 74

Thirteen Escherichia coli strains of different biotypes isolated from urine and faeces cultures were studied for metabolic and compositional changes during starvation in seawater at different timepoints. Additionally, the antibiotic susceptibility of the starved E. coli cells was evaluated over time on Mueller-Hinton agar (Bauer-Kirby method). All starved E. coli cells lost beta-galactosidase activity gradually with time and acquired the ability to degrade gelatine. Nine of the E. coli strains lost the ability to decarboxylate lysine and seven to acidify melibiose. C4 esterase, C8 esterase lipase, leucine arylamidase and C14 lipase activity increased during starvation, while alkaline and acid phosphatase and phosphoamidase activity decreased. Most of the E. coli strains underwent alterations in their electrophoretic protein pattern. The traditional Bauer & Kirby method was shown to be inadequate for testing antibiotic susceptibility of starved strains.
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PMID:Metabolic and compositional changes in Escherichia coli cells starved in seawater. 784 33

1. The termite, Odentotermes horni. W., houses three fungal species, viz. Xylaria nigripes, Termitomyces microcorpus, and Trichoderma (species not identified), in its gut. X. nigripes was found to possess higher esterase activity levels than the other two. 2. Four esterase enzymes, viz. FE-I, -II, -III and -IV, with pI values 5.1, 5.25, 5.4 and 5.6, respectively, were identified, isolated and purified to apparent homogeneity from the fungus X. nigripes, their biochemical and enzymological properties were determined, and compared with those of the previously characterized host termite mid-gut enzymes, TE-I and -II. 3. The M(r) of FE-I and -II was 85.1 kDa and those of FE-III and -IV was 87.5 kDa. However, TE-I and -II were relatively smaller (M(r) approximately 78.5 kDa). Each of the fungal enzymes, viz. FE-I to -IV, was a homodimer with subunits associated non-covalently. The subunit M(r) were 42.6 kDa for FE-I and -II, and 43.7 kDa for FE-III and -IV. On the other hand, the termite mid-gut enzymes, TE-I and -II, were also homodimeric, but the subunits were associated covalently (subunit M(r) = 40 kDa). Immunologically the fungal esterase enzymes, viz. FE-I to -IV, were different from those of the host termite mid-gut esterases, viz. TE-I and -II. 4. The substrate specificity and inhibitor sensitivity studies classify these enzymes, i.e. FE-I to -IV, as carboxylesterases (EC 3.1.1.1). Steady-state product inhibition kinetics suggested; an ordered release of products, i.e. alcohol followed by acid, and a Uni-Bi kinetic reaction mechanism. 5. The two preliminary studies, i.e. the confinement of most esterase activity to the gut-tissue free from microorganisms and starvation of termites not leading to complete loss of esterase activity in the gut of the termites, suggested that there may not be any symbiotic relationship between termite, O. horni, and its gut associated microorganisms with regard to ester metabolism. Though the enzymes from the two sources were carboxylesterases, several of their properties were different and hence, they are different entities.
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PMID:Isolation and properties of carboxylesterases of the termite gut-associated fungus, Xylaria nigripes. K., and their identity from the host termite, Odentotermes horni. W., mid-gut carboxylesterases. 828 33

Escherichia coli O157:H7 can persist for days to weeks in microcosms simulating natural conditions. In this study, we used a suite of fluorescent, in situ stains and probes to assess the influence of starvation on physiological activity based on membrane potential (rhodamine 123 assay), membrane integrity (LIVE/DEAD BacLight kit), respiratory activity (5-cyano-2,3-di-4-tolyl-tetrazolium chloride assay), intracellular esterase activity (ScanRDI assay), and 16S rRNA content. Growth-dependent assays were also used to assess substrate responsiveness (direct viable count [DVC] assay), ATP activity (MicroStar assay), and culturability (R2A agar assay). In addition, resistance to chlorine disinfection was assessed. After 14 days of starvation, the DVC values decreased, while the values in all other assays remained relatively constant and equivalent to each other. Chlorine resistance progressively increased through the starvation period. After 29 days of starvation, there was no significant difference in chlorine resistance between control cultures that had not been exposed to the disinfectant and cultures that had been exposed. This study demonstrates that E. coli O157:H7 adapts to starvation conditions by developing a chlorine resistance phenotype.
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PMID:Effects of starvation on physiological activity and chlorine disinfection resistance in Escherichia coli O157:H7. 983 45


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