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

The response of the marine Vibrio sp. strain S14 to starvation for carbon, nitrogen, or phosphorus and to simultaneous depletion of all these nutrients (multiple-nutrient starvation) was examined with respect to survival, stress resistance, quantitative and qualitative alterations in protein and RNA synthesis, and the induction of the stringent control. Of the conditions tested, carbon starvation and multiple-nutrient starvation both promoted long-term starvation resistance and a rapid induction of the stringent control, as deduced from the kinetics of RNA synthesis. Carbon- and multiple-nutrient-starved cells were also found to become increasingly resistant to heat, UV, near-UV, and CdCl2 stress. Nitrogen- and phosphorus-starved cells demonstrated a poor ability to survive in the presence of carbon and did not develop a marked resistance to the stresses examined. The carbon, nitrogen, and phosphorus starvation stimulons consisted of about 20 proteins each, while simultaneous starvation for all the nutrients elicited an increased synthesis of 42 polypeptides. Nine common proteins were found to be induced regardless of the starvation condition used and were tentatively termed general starvation proteins. It was also demonstrated that the total number of proteins induced in response to multiple-nutrient starvation was not a predictable sum of the different individual starvation stimulons. Multiple-nutrient starvation induced 14 proteins which were not detected at increased levels of expression in response to individual starvation conditions. Furthermore, four out of five phosphorus starvation-specific polypeptides were not induced during simultaneous starvation for phosphorus, nitrogen, and carbon. The results are discussed in light of the physiological alterations previously described for Vibrio sp. strain S14 cells starved for carbon, nitrogen, and phosphorus simultaneously.
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PMID:Survival, stress resistance, and alterations in protein expression in the marine vibrio sp. strain S14 during starvation for different individual nutrients. 137 61

Carbon starvation induces the development of a starvation- and stress-resistant cell state in marine Vibrio sp. strain S14 (CCUG 15956). The starved cells remain highly responsive to nutrients during prolonged starvation and exhibit instantaneous severalfold increases in the rates of protein synthesis and RNA synthesis when substrate is added. In order to elucidate the physiological basis for the survival of cells that are starved for a long time, as well as the capacity of these cells for rapid and efficient recovery, we analyzed the ribosome content of carbon-starved Vibrio sp. strain S14 cells. By using direct chemical measurements of the amounts of ribosomal particles in carbon-starved cultures, we demonstrated that ribosomes were lost relatively slowly (half life, 79 h) and that they existed in large excess over the apparent demand for protein synthesis. After 24 h of starvation the total rate of protein synthesis was 2.3% of the rate during growth, and after 3 days this rate was 0.7% of the rate during growth; the relative amounts of ribosomal particles at these times were 81 and 52%, respectively. The ribosome population consisted of 90% 70S monoribosomes, and no polyribosomes were detected in the starved cells. The 70S monoribosomes were responsible for the bulk of the protein synthesis during carbon starvation; some activity was also detected in the polyribosome size region on sucrose density gradients. We suggest that nongrowing carbon-starved Vibrio sp. strain S14 cells possess an excess protein synthesis capacity, which may be essential for their ability to immediately initiate an upshift program when substrate is added.
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PMID:Ribosomes exist in large excess over the apparent demand for protein synthesis during carbon starvation in marine Vibrio sp. strain CCUG 15956. 138 95

The response of marine Vibrio sp. strain S14 (CCUG 15956) to long-term (48-h) multiple-nutrient starvation (i.e., starvation for glucose, amino acids, ammonium, and phosphate simultaneously) can be described as a three-phase process. The first phase, defined as the stringent control phase, encompasses an accumulation of guanosine 5'-diphosphate 3'-diphosphate (ppGpp) and decreases in RNA and protein synthesis during the first 40 min. In the second phase, there is a temporary increase in the rates of RNA and protein synthesis between 1 and 3 h paralleling a decrease in the ppGpp pool. The third phase includes gradual decline in macromolecular synthesis after 3 h. Using two-dimensional gel electrophoresis of pulse-labeled proteins, a total of 66 proteins were identified as starvation inducible (Sti), temporally expressed throughout the three phases of starvation. The inhibition of protein synthesis during the first phase of starvation partly disrupted the subsequent temporally ordered synthesis of starvation proteins and prevented the expression of some late starvation proteins. It was also found that the early temporal class of starvation proteins, which included the majority of the Sti proteins, was the most essential for long-term survival. Vibrio sp. strain S14 cultures prestarved (1 h) for glucose, amino acids, ammonium, or phosphate as well as cultures exposed (1 h) to CdCl2 exhibited enhanced survival during the subsequent multiple-nutrient starvation in the presence of chloramphenicol or rifampin, while heat or the addition of cyclic AMP or nalidixic acid prior to starvation had no effect. It was demonstrated that amino acid starvation and CdCl2 exposure, which induced the stringent response, were the most effective in conferring enhanced survival. A few Sti proteins were common to all starvation conditions. In addition, the total number of proteins induced by multiple-nutrient starvation significantly exceeded the sum of those induced by starvation for each of the individual nutrients.
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PMID:Responses to multiple-nutrient starvation in marine Vibrio sp. strain CCUG 15956. 170 28

The uptake kinetics of D-glucose were examined in the marine Vibrio sp. S14 during a period of 168 h of complete energy and nutrient starvation. Two glucose transport systems were distinguished in Vibrio sp. S14: a low affinity system (Km = 4.6 +/- 0.9 microM) at the onset of starvation, and a high affinity system (Km = 0.55 +/- 0.15 microM) after 168 h of starvation. Both systems had a narrow substrate specificity, and both were osmotic shock-sensitive.
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PMID:Starvation-induced modulations in binding protein-dependent glucose transport by the marine Vibrio sp. S14. 222 57

Vegetatively growing amoebae, if shaken in a starvation (nonnutrient) buffer, acquired aggregation competence, but do not embark on a morphogenetic program. The quantitative variation of ribosomal proteins in vegetative and aggregation-competent cells was compared by labeling the different cell types with [35S]methionine. Vegetative cells were examined at various phases of the growth cycle. No changes could be detected in the content of ribosomes or the apparent stoichiometry of ribosomal proteins in growing cells. In stationary phase cells, the net ribosome content declined to 15% of that observed in logarithmic phase, but the relative amounts of individual ribosomal proteins were not altered. Although aggregation-competent cells contained 30% less ribosomes compared with logarithmic phase cells, the total fraction of newly made ribosomal proteins was the same in both. In contrast to vegetative cells, distinct changes were induced in the ribosomal proteins of aggregation-competent cells. The composition of ribosomes in aggregation-competent phase resembled in every respect that observed in spore cells. As reported earlier, changes were found in all 12 of the developmentally regulated ribosomal proteins. For the majority of newly made ribosomal proteins during aggregation competence, the stoichiometry was similar to that in logarithmically growing cells. However, the relative synthesis of some was particularly higher (13- to 46-fold for A and L; 3- to 8-fold for D, E, S24, L3, S6, and L4) compared with logarithmic phase cells. About 18 proteins, which included the cell-specific ribosomal proteins L18, S10, S14, S16, and L11, were synthesized in lesser amounts than in logarithmic phase cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Induction of cell-specific ribosomal proteins in aggregation-competent nonmorphogenetic Dictyostelium discoideum. 227 4

Dietary carbohydrate and thyroid hormone (T3) interact to regulate rat liver S14 gene expression. The molecular basis for this interaction was examined by analysis of hepatic mRNAS14 levels, S14 gene transcription, and chromatin structure. While starvation of euthyroid rats inhibited hepatic S14 gene transcription greater than or equal to 90%, sucrose administration induced mRNAS14 and S14 transcription to 82% of euthyroid-fed levels within 4 h. In contrast, administration of sucrose or T3 to starved hypothyroid animals restored S14 gene transcription to only 30% of euthyroid-fed values. Both T3 and sucrose were required to restore S14 run-on activity and mRNAS14 to euthyroid-fed levels within 4 h. Thus, T3 and sucrose interact synergistically and rapidly to induce S14 gene transcription. Analysis of S14 chromatin structure showed that starvation of hypothyroid rats inhibited the formation of three DNase I-hypersensitive sites flanking the 5'-end of the S14 gene (Hss-1 at -65 to -265 base pairs; Hss-2 at -1.2 kilobases and Hss-3 at -2.67 kilobases). The loss of these sites correlated with the repression of S14 gene transcription in starved hypothyroid rats. Whereas administration of sucrose to starved hypothyroid rats consistently induced the Hss-1 and Hss-2 sites, T3 consistently induced all three DNase I-hypersensitive sites. Yet, neither treatment alone induced S14 gene transcription to euthyroid levels. The combination of T3 and sucrose induced no additional change in S14 chromatin structure over that induced by T3 alone. Thus, regulation of S14 chromatin structure alone is not the sole mechanism by which these stimuli regulate S14 gene transcription. We speculate that the synergistic regulation of S14 gene transcription by T3 and dietary carbohydrate involves a complex interaction between factors which regulate the accessibility of putative cis-regulatory elements through changes in chromatin structure and the regulation of "transcription factors" which interact with these elements.
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PMID:Thyroid hormone and dietary carbohydrate interact to regulate rat liver S14 gene transcription and chromatin structure. 230 55

Changes in membrane and periplasmic protein profiles induced by starvation conditions in the marine Vibrio sp. S14 were examined by one-dimensional gel electrophoresis. Analysis by densitometry resolved at least six periplasmic proteins, nine outer membrane proteins, and four cytoplasmic membrane proteins induced at various times during 120 h of nutrient and energy starvation. Eight of these were also synthesized by heat- and/or ethanol-shocked cells. Pulse-labelling indicated that the starvation-induced proteins were not products of degradation, and that their synthesis was differently modulated during starvation. The most pronounced changes occurred during the initial hours of nutrient and energy deprivation. The correlation between the initial changes in protein composition and utilization of the intracellular energy reserve poly-beta-hydroxybutyrate is discussed. The rate of proteolysis during the initial hours of starvation was approximately 16 times greater than that during exponential growth.
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PMID:Synthesis of membrane and periplasmic proteins during starvation of a marine Vibrio sp. 322 Dec 1

A carbon starvation-responding lac fusion of the marine Vibrio sp. strain S14 was used as a reporter strain in order to identify genes critical in the regulation of the carbon starvation response. Interestingly, sequence data together with an altered phenotype with respect to the accumulation of guanosine 3',5'-bispyrophosphate (ppGpp) imply that one of the genes (csrS) identified by this approach is an Escherichia coli spoT equivalent. Complementary data suggest that the function encoded by the csrS gene is essential for the successful development of starvation and stress resistance.
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PMID:Isolation of a carbon starvation regulatory mutant in a marine Vibrio strain. 759 94

The Escherichia coli DnaK homologue in Vibrio sp. strain S14 was shown to possess chaperone function for translocation during carbon starvation. This was demonstrated by using the method of co-immunoprecipitation. DnaK co-precipitated with the carbon starvation-specific periplasmic space protein Csp5 three hours after the onset of carbon starvation. Pulse-chasing of the protein with radiolabelled methionine followed by the addition of an excess of unlabelled methionine demonstrated that the Csp5 protein was translocated across the inner membrane. Only the cytoplasmic unprocessed precursor form of Csp5 co-precipitated with DnaK. The non-covalent binding between the two proteins was found to be ATP-dependent, as the addition of ATP released the interaction between DnaK and the precursor form of Csp5, as was shown on silver-stained SDS-polyacrylamide gels and by Western blot analysis. We suggest that DnaK maintains the carbon starvation-inducible protein Csp5 in a translocation-competent form in the cytoplasm.
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PMID:The DnaK homologue of the marine Vibrio sp. strain S14 binds to the unprocessed form of a carbon starvation-specific periplasmic protein. 791 11

In order to evaluate the role of the stringent response in starvation adaptations of the marine Vibrio sp. strain S14, we have cloned the relA gene and generated relaxed mutants of this organism. The Vibrio relA gene was selected from a chromosomal DNA library by complementation of an Escherichia coli delta relA strain. The nucleotide sequence contains a 743-codon open reading frame that encodes a polypeptide that is identical in length and highly homologous to the E. coli RelA protein. The amino acid sequences are 64% identical, and they share some completely conserved regions. A delta relA::kan allele was generated by replacing 53% of the open reading frame with a kanamycin resistance gene. The Vibrio relA mutants displayed a relaxed control of RNA synthesis and failed to accumulate ppGpp during amino acid limitation. During carbon and energy starvation, a relA-dependent burst of ppGpp synthesis concomitant with carbon source depletion and growth arrest was observed. Also, in the absence of the relA gene, there was an accumulation of ppGpp during carbon starvation, but this was slower and smaller than that which occurred in the stringent strains, and it was preceded by a marked decrease in the [ATP]/[ADP] ratio. In both the wild-type and the relaxed strains, carbon source depletion caused an immediate decrease in the size of the GTP pool and a block of net RNA accumulation. The relA mutation did not affect long-term survival or the development of resistance against heat, ethanol, and oxidative stress during carbon starvation of Vibrio sp. strain S14.
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PMID:Stringent control during carbon starvation of marine Vibrio sp. strain S14: molecular cloning, nucleotide sequence, and deletion of the relA gene. 792 55


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