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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A series of deletions removing progressively larger parts of the 5' flanking region of the Escherichia coli pepD gene was constructed. After fusing the resulting promoter fragments to the chromosomal malPQ operon, their activities were determined by assaying for amylomaltase, the product of the malQ gene. Transcription from the pepD promoter region in exponentially growing cells was estimated to be about 5 times less efficient than transcription from the induced lac promoter. Approximately 115 bp preceding the translation start site of the pepD gene are important for regular promoter functioning, whereas the more distal sequences could be deleted without any significant effects. In bacterial cultures containing limiting amounts of inorganic phosphate, the rate of de novo synthesis of peptidase D, simultaneously with the derepression of alkaline phosphatase, increased about fivefold as a consequence of phosphate starvation. This regulation was shown to occur at the transcriptional level by the use of chromosomal pepD promoter-malPQ fusions. The inducibility by phosphate limitation was conserved in all of the deletion clones in which the pepD promoter region was still functional. As demonstrated by the use of phoB, R, and M mutants, the modulation of pepD expression is independent of the genetic system controlling the pho regulon.
Mol Gen Genet 1992 Mar
PMID:The promoter region of the Escherichia coli pepD gene: deletion analysis and control by phosphate concentration. 131 42

Schizosaccharomyces pombe initiates sexual development in response to nutritional starvation. The level of cAMP in S. pombe cells changed during the transition from exponential growth to stationary phase. It also changed in response to a shift from nitrogen-rich medium to nitrogen-free medium. A decrease of approximately 50% was observed in either case, suggesting that S. pombe cells contain less cAMP when they initiate sexual development. S. pombe cells that expressed the catalytic domain of Saccharomyces cerevisiae adenylyl cyclase from the S. pombe adh1 promoter contained 5 times as much cAMP as the wild type and could not initiate mating and meiosis. These observations, together with previous findings that exogenously added cAMP inhibits mating and meiosis and that cells with little cAMP are highly derepressed for sexual development, strongly suggest that cAMP functions as a key regulator of sexual development in S. pombe. The pde1 gene, which encodes a protein homologous to S. cerevisiae cAMP phosphodiesterase I, was isolated as a multicopy suppressor of the sterility caused by a high cAMP level. Disruption of pde1 made S. pombe cells partially sterile and meiosis-deficient, indicating that this cAMP phosphodiesterase plays an important role in balancing the cAMP level in vivo.
Mol Gen Genet 1992 May
PMID:Reduction in the intracellular cAMP level triggers initiation of sexual development in fission yeast. 131 97

Starvation of Saccharomyces cerevisiae cells for specific nutrients such as nitrogen, phosphate or sulphate causes arrest in the G1 phase of the cell cycle at a specific point called 'start'. Re-addition of different nitrogen sources, phosphate or sulphate to such starved cells causes activation of trehalase within a few minutes. Nitrogen-source- and sulphate-induced activation of trehalase were not associated with any change in the cAMP level, but in the case of phosphate there was a small transient increase. When nitrogen-source-activated trehalase was isolated by immuno-affinity chromatography from crude extracts, the purified enzyme showed the same activity profile as in the original crude extracts, indicating that post-translational modification is responsible for the activation. In the yeast mutants cdc25-5 and cdc35-10, which are temperature sensitive for cAMP synthesis, incubation at the restrictive temperature lowered but did not prevent nitrogen-, phosphate- or sulphate-induced activation of trehalase. Since under these conditions the cAMP level in the cells is very low, it is unlikely that cAMP acts as a second messenger in this nutrient-induced effect. Nitrogen-source-induced activation of trehalase requires the presence of glucose at a concentration similar to that able to stimulate the RAS-adenylate cyclase pathway. This indicates that the same glucose-sensing system might be involved in both phenomena. Nitrogen-starved cells fractionated according to cell size all showed nitrogen-source-induced activation of trehalase to the same extent, indicating that the nitrogen-induced signalling pathway involved is not dependent on the well-known cell size requirement for progression over the start point of the cell cycle.
J Gen Microbiol 1992 Oct
PMID:Nutrient-induced activation of trehalase in nutrient-starved cells of the yeast Saccharomyces cerevisiae: cAMP is not involved as second messenger. 133 29

We have previously shown that resistance to the beta-lactam mecillinam in Escherichia coli can be brought about by a high ppGpp pool, as observed under conditions of partial amino acid starvation and RelA-dependent induction of the stringent response. We show here that our E. coli wild-type strain, which is sensitive to mecillinam on minimal glucose plates, becomes resistant in the presence of L-leucine or L-serine (or cysteine, which inactivates the antibiotic). The resistance, which is not a transient effect and does not depend on the physiological state of the cells when plated, is specific for mecillinam and is reversed by the presence of isoleucine and valine in the medium. At least in the case of serine, the resistance is RelA-dependent. We conclude that the presence of leucine and serine in the growth medium cause partial starvation for isoleucine/valine, leading to induction of the stringent response and concomitant resistance to mecillinam.
Mol Gen Genet 1992 Nov
PMID:Leucine and serine induce mecillinam resistance in Escherichia coli. 146 98

We have previously suggested that two positioned nucleosomes are removed from the promoter of the Saccharomyces cerevisiae SUC2 gene upon depression by glucose starvation. To gain further insight into the changes accompanying derepression at the chromatin level we have studied the chromatin structure of the SUC2 promoter in several mutants affecting SUC2 expression. The non-derepressible mutants snf1, snf2 and snf5 present a chromatin structure characteristic of the repressed state, irrespective of the presence or absence of glucose. The non-repressible mutants, mig1 and ssn6, as well as the double mutant snfs sn6 exhibit an opened chromatin structure even in the presence of glucose. These results suggest that the DNA-binding protein encoded by MIG1 is necessary to produce the characteristic pattern of repressed chromatin and that the SNF1 protein kinase is sufficient to produce the derepressed chromatin pattern. A model is presented for the transitions that result in opening up of the chromatin structure.
Mol Gen Genet 1992 Feb
PMID:Chromatin structure of the yeast SUC2 promoter in regulatory mutants. 153 95

A tumour-specific polypeptide designated U90 is one of a set of polypeptides which are encoded by the host cell and are specific for the transformed cell state, being immunoprecipitated by the sera of tumour-bearing animals. The interest in these tumour-specific polypeptides centres on the finding that they are also recognized by antisera raised against herpes simplex virus type 2 (HSV-2)-infected cells, implying some role for HSV-2 in tumorigenesis. The peptide map of HSV-2-induced U90 is indistinguishable from that of U90 present in uninfected tumour cells, including mouse cells transformed by human papillomavirus type 16. In tumour cells, U90 is located principally in the plasma membrane fraction and cannot be induced by heat shock, glucose starvation, or treatment with tunicamycin or calcium ionophore. U90 is not related to either the heat shock protein of Mr 90,000 (HSP90) or the glucose-related polypeptide of Mr 94,000 (GRP94) as determined by peptide mapping and the use of monospecific, monoclonal and antipeptide antibodies. This suggests that U90 is a novel transformation-specific protein which can be induced by infection with HSV-2.
J Gen Virol 1991 Dec
PMID:A transformation-specific polypeptide distinct from heat shock proteins is induced by herpes simplex virus type 2 infection. 166 99

The gene products of the ugp operon of Escherichia coli are responsible for the uptake of sn-glycerol-3-phosphate and certain glycerophosphodiesters. The regulation of ugp is mainly phoBR-dependent. Significant expression, however, can be observed even in the presence of high concentrations of phosphate, a condition which normally completely represses pho expression. Pho-independent ugp expression was found to be derepressed during the late logarithmic growth phase due to carbon starvation. Among different carbon sources tested, glucose caused the most complete repression. Addition of cAMP prevented glucose repression, indicating that a cAMP-CRP control mechanism may be directly or indirectly involved in the carbon-starvation response. This conclusion is supported by the fact that pho-independent ugp expression correlated with the presence of the cya and crp gene products.
Mol Gen Genet 1991 Nov
PMID:Carbon-starvation induction of the ugp operon, encoding the binding protein-dependent sn-glycerol-3-phosphate transport system in Escherichia coli. 174 36

The first events of lambda plasmid replication in vivo, which probably regulate this process, are the transcriptional activation of the origin of replication by RNA polymerase and the binding of the initiator protein, lambda O, to this nucleotide sequence. The lambda O protein is known for its rapid proteolytic degradation; hence amino acid starvation of Escherichia coli should result in inhibition of lambda plasmid replication caused by inhibition of protein synthesis. However, contrary to this prediction, we found that lambda plasmid replication, as measured by the increase in plasmid content per bacterial mass, proceeds for hours in an amino acid-starved, relaxed mutant, whereas it is inhibited in its wild-type stringent partner. lambda plasmid replication in amino acid-starved, relaxed cells reveals absolute lambda O dependence and is not inhibited by chloramphenicol at 200 micrograms/ml. This process also occurs in wild-type cells treated with chloramphenicol. We conclude that lambda plasmid replication is under stringent control, probably as a result of the action of ppGpp, the indirect product of the relA gene, on RNA polymerase. The problem of stability of the lambda O initiator protein is discussed.
Mol Gen Genet 1991 Jan
PMID:Stringent control of replication of plasmids derived from coliphage lambda. 182 94

Two experiments, one using 0+ the other 1+ rainbow trout, were conducted to investigate the effect of prolonged starvation on plasma growth hormone levels. The results from both experiments were essentially the same. As expected, starvation resulted in cessation of growth and in a lower coefficient of condition, whereas fed fish continued to grow and remained in good condition. Starvation had relatively little effect on the plasma cortisol level; in one experiment levels were elevated temporarily in starved fish, although by the end of the experiment there was no longer any difference between starved and fed fish, and in the other experiment plasma cortisol levels remained very low throughout the course of the experiment in both starved and fed fish. In contrast, in both experiments starvation had a pronounced effect on the plasma growth hormone level, which rose steadily during both experiments, such that it was six times higher after 1 month of starvation in 0+ fish, and five times higher after 6 weeks of starvation in 1+ fish. Thus, paradoxically, fed fish had very low plasma growth hormone levels and grew rapidly, whereas starved fish had elevated plasma growth hormone levels but did not grow. In both experiments a strong negative correlation was observed between the plasma growth hormone level and the coefficient of condition of the fish. The results are discussed with regard to the well-established metabolic changes that occur during starvation, and it is suggested that a major role of growth hormone during starvation is to aid in the mobilisation of fatty acids and glycerol from adipose stores.
Gen Comp Endocrinol 1991 Jul
PMID:The effect of starvation on growth and plasma growth hormone concentrations of rainbow trout, Oncorhynchus mykiss. 187 76

Twenty four hours after an intraperitoneal injection of thyroxine (T4; 4.4, 44 ng/g body wt) or triiodothyronine (T3; 3.3, 33 ng/g body wt), DNA and RNA were significantly reduced in isolated liver mitochondria of rainbow trout. Total liver DNA was increased with the higher doses in both T4- and T3-injected specimens while total RNA was significantly reduced with the same doses. Total circulating plasma T4 was reduced with the injections of T3 or starvation, and plasma T3 was increased severalfold with the T3 injections. Plasma T4 also increased fivefold after a higher dose of T4 injection while starvation significantly reduced the concentration, when measured by radioimmunoassay.
Gen Comp Endocrinol 1991 Sep
PMID:The effects of thyroid hormones and starvation on hepatic mitochondrial nucleic acids of rainbow trout (Oncorhynchus mykiss). 193 29


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