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)

Certain treatments that damage DNA and/or inhibit replication in E. coli have been reported to induce synthesis of a new protein, termed protein X, in recA+ lexA+ strains. We have examined some of the treatments that might induce protein X and we have, in particular, tested the hypothesis of Gudas and Pardee (1975) that DNA degradation products play an essential role in the induction process. We confirmed that UV irradiation, nalidixic acid treatment, or thymine starvation result in protein X synthesis in wild type strains. However, we found that UV irradiation, unlike nalidixic acid, also induced protein X in recB strains, in which little DNA degradation occurs. Furthermore, we found that the presence of DNA fragments resulting from host-controlled restriction of phage lambda DNA did not affect protein X synthesis. We conclude that no causal relationship exists between the production of DNA fragments and induction of protein X. The presence of the plasmid R46, which confers enhanced mutagenesis and UV resistance on its host, did not affect protein X synthesis. Growth in the presence of 5-bromouracil, which does not result in production of degradation fragments, resulted eventually in a low rate of protein X synthesis. In dnaA mutants, deficient in the initiation of new rounds of replication, UV irradiation induced protein X, again unlike nalidixic acid. Thus, the inhibition of active replication forks is not an essential requirement for protein X induction.
Mol Gen Genet 1977 Feb 15
PMID:Induction of protein X in Escherichia coli. 32 32

The development of resistance to amphotericin methyl ester, measured in terms of the amount of drug required to induce a standard rate of release of K+ from suspensions of washed organisms, has been followed in Candida albicans in starved cultures under controlled conditions of aeration, stirring and temperature. Resistance develops at a rate which increases with the rate of aeration, limited by the onset of damage due to turbulence. Resistance decreases rapidly if gassing with N2 is substituted for aeration, but sensitivity does not reach that of exponentially growing cells. Resumption of aeration is followed by a slow recovery of resistance. The addition of inhibitors of protein synthesis (trichodermin, verrucarin) or uncoupling agents (2,4-dinitrophenol, sodium azide) at the beginning of starvation results in an increased rate of development of resistance. Adding inhibitors at a later stage, when resistance has developed after 72 h aeration, does not affect the decrease in resistance produced by gassing with N2 but the presence of trichodermin or verrucarin delays the recovery of resistance o
J Gen Microbiol 1977 Mar
PMID:The effect of aeration and metabolic inhibitors on resistance to amphotericin in starved cultures of Candida albicans. 32 78

We have followed, by DNA-DNA hybridization, the variation in the number of copies of prophage P1 relative to two chromosomal markers when the doubling time of the host cells is modified by a change in carbon source. The ratio of P1/chromosome terminus undergoes a twofold decrease when the cell doubling time increases from 24 to 215 min, whereas the ratio of P1/chromosome origin increases 1.4 fold; both ratios tend towards unity at slow growth rates. This suggests that the replication of prophage P1 is not simultaneous with chromosome initiation or chromosome termination. The chromosome replication time is unaffected by the presence of P1, and remains constant over the range of doubling times studied, with a value of about 4o min. Following amino acid starvation, the P1/chromosome origin ratio increases from 0.7 to 0.9, suggesting that P1 retains the ability to replicate after chromosome initiation has stopped and in the absence of essential amino acids. The results are discussed with reference to similar studies done on F and R1.
Mol Gen Genet 1977 Mar 28
PMID:Replication of prophage P1 during the cell cycle of Escherichia coli. 32 89

The effect of amino acid-starvation on the transcription in vitro of overall RNA and ribosomal RNA was investigated using nucleoids prepared from the exponentially growing and the amino acid-starved cells of rel+ and rel- strains of Escherichia coli. In this system, the synthesis of RNA is exclusively due to elongation of the chains which have been initiated in vivo. The amounts of overall and ribosomal RNA synthesized per unit of DNA in the nucleoids were analyzed for each preparation. The following observations have been made. (1) The total RNA synthesis per unit of DNA in the nucleoids from the amino acid-starved rel+ and rel- cells was not significantly different from each other. (2) The preferential ribosomal RNA synthesis occurred in the nucleoids from the growing cells; the ribosomal RNA synthesis was restricted in the nucleoids from the starved rel+ cells, while no restriction was observed in the nucleoids from the starved rel- cells. The results suggest that the ribosomal RNA synthesis is regulated at the initiation or less likely elongation level of the transcription. (3) A ribosomal RNA of a discrete size of about 30S was synthesized in the nucleoids. No mature ribosomal RNA species was produced in this system. The 30S RNA is probably a primary transcript of ribosomal RNA genes containing 23S, 16S and 5S mature ribosomal RNA sequences.
Mol Gen Genet 1977 Apr 29
PMID:Control of ribosomal RNA synthesis in Escherichia coli. II. Ribosomal RNA synthesis in isolated nucleoids. 32 72

The synthesis of tRNA in yeast is shown to be under separate control to that of rRNA during amino acid and nitrogen starvation. Inhibitors of the elongation and termination steps of protein synthesis were found to stimulate the synthesis of tRNA in starved yeast cells. This effect appeared to be due to the "trickle-charging" of tRNA. Two inhibitors of early steps in the initiation of protein synthesis were found to be unable to stimulate RNA synthesis in starved cells. It is proposed that yeast tRNA synthesis is under autoregulatory control and that the level of tRNA charging and the mRNA-ribosome complex are important components of this control system.
Mol Gen Genet 1977 Jul 20
PMID:The regulation of RNA synthesis in yeast. I: Starvation experiments. 33 Oct 81

Escherichia coli, cultured on minimal medium and deprived of its required amino-acids, was induced for lac genes transcription. After inducer removal and restoration of growth, beta-galactosidase synthesis was measured. Two different kinetics of enzyme synthesis were observed depending on the starvation conditions employed during the induction period: 1. beta-galactosidase synthesis was immediately obtained and a plateau was reached, in 20 min after restoration of growth, when cells had been induced during deprivation of amino-acids and carbon source. 2. beta-galactosidase displayed an unusually long rate of synthesis, and plateau was not reached before two doubling times, when cells had been induced during the deprivation of the sole amino-acids. The latter result points out a problem of messenger stability during those long translation kinetics and led us to study the behaviour of strains carrying lac genetic determinants on different replicative structures; chromosomic and plasmidic. In those two situations, induction of lac messenger RNA was obtained and ratify our previous observations. However, their translation kinetics suggest a DNA linkage of this induced messenger.
Mol Gen Genet 1977 Nov 14
PMID:Unusual stability and translation kinetics of an Escherichia coli lac messenger RNA synthetized during amino-acids deprivation. 34 Sep 4

Mutants of LexB have been isolated by their resistance to lysogenic induction by thymine starvation, their resistance to thymine starvation and on the basis of their UV sensitivity. Here, three mutations identified originally in strains lacking mutagenic response to UV-irradiation, unmB (Kato and Shinoura, 1977), have been further characterized, mapped by P1-mediated transduction with srl into the recA-tif-zab-lexB cluster at the lexB position and analysed for complementation with various lexB and recA mutations. From the results it was concluded that unmB mutations are identical to lexB mutations; consequently these mutations have been termed lexB32, lexB33 and lexB35. The mutations lexB33 and lexB35 do not complement any of the other lexB mutations and define therefore a new complementation type. The lexB32 mutation, which like the lexB34 mutation, results in moderate UV sensitivity has a complementation pattern similar to that of lexB34. However, unlike lexB34 the lexB32 behaves like a leaky mutation. The results are discussed in relation to the recA gene product and its control.
Mol Gen Genet 1977 Nov 29
PMID:The genetic characterization of lexB32, lexB33 and lexB35 mutations of Escherichia coli: location and complementation pattern for UV resistance. 34 Sep 15

The ribosomal proteins of 11 mutants which are sensitive to starvation at elevated temperature and of 36 transductants derived from them were studied with several electrophoretic, immunochemical and proteinchemical methods. The following results were obtained: (1) Ribosomal protein S8 is altered in three of these mutants. (2) The amino acid exchange in proteins S8 of mutant N4128 is Glu leads to Lys in position 59 of the protein chain. (3) Temperature sensitivity and inability to recover from starvation at elevated temperatures are caused by the same mutational event which is, however, unrelated to the alteration in protein S8. Several electrophoretic and immunological procedures were applied during the characterization of these mutants. A modified immunoelectrophoresis on cellulose acetate gels was developed, and proved to be the most applicable procedure for the detection of mutationally altered ribosomal proteins. This procedure may gain general importance for detecting mutational alterations in other proteins.
Mol Gen Genet 1977 Dec 30
PMID:Improved electrophoretic and immunochemical techniques for the identification and characterization of mutant proteins, applied to ribosomal protein S8 in Escherichia coli mutants. 34 Sep 33

Thymidylate starvation in a yeast mutant auxotrophic for dTMP caused cell death and the induction of mutations in the mitochondrial genome. After 24 h of starvation almost all surviving cells were respiratory deficient petites. In addition, shorter episodes of dTMP starvation induced chloramphenicol and erythromycin resistant mutants, indicating the occurrence of mitochondrial point mutations. Suboptimal concentrations of exogenous thymidylate were also found to induce petites and a decline in cell viability and the magnitude of these effects was acutely dependent upon the dTMP concentration. Cesium chloride gradient analysis of DNA from cells undergoing thymineless incubation revealed a progressive loss of mitochondrial DNA, and a decrease in the molecular weight of nuclear DNA.
Mol Gen Genet 1978 Mar 20
PMID:Genetic damage during thymidylate starvation in Saccharomyces cerevisiae. 34 46

The simultaneity of the presence of substrate (inducer) and the absence of a better nitrogen nutrient causes a strong cooperative effect (catabolic synergism) on arginase production. This effect is shown to operate by a specific mechanism. carg A+ 0h mutation (Dubois et al., 1978) identifies an element of this process located near the arginase structural gene and acting in cis. This mutation produces constitutivity for synergism in addition to constitutivity for induction (this last effect is produced alone by cargA +0- operator constitutive mutation). The receptor of the signal for the presence of substrate is the same as for induction. cargA + 0h mutation allows to make further distinction between the promotion of arginase synthesis caused by nitrogen limitation and nitrogen starvation.
Mol Gen Genet 1978 Sep 08
PMID:Catabolic synergism: a cooperation between the availability of substrate and the need for nitrogen in the regulation of arginine catabolism in Saccharomyces cerevisiae. 36 56


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