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

A significant seasonal variation in size at settlement has been observed in newly settled larvae of Dreissena polymorpha in Lake Constance. Diet quality, which varies temporally and spatially in freshwater habitats, has been suggested as a significant factor influencing the life history and development of freshwater invertebrates. Accordingly, experiments were conducted with field-collected larvae to test the proposal that diet quality can determine planktonic larval growth rates, size at settlement and subsequent post-metamorphic growth rates. Larvae were fed one of two diets or starved. One diet was composed of cyanobacterial cells, which are deficient in polyunsaturated fatty acids (PUFAs) and the other was a mixed diet rich in PUFAs. Freshly metamorphosed animals from the starvation treatment had a carbon content per individual 70% lower than that of larvae fed the mixed diet. This apparent exhaustion of larval internal reserves resulted in a 50% reduction of the post-metamorphic growth rates. Growth was also reduced in animals previously fed the cyanobacterial diet. Hence, low food quantity or low food quality during the larval stage of D. polymorpha, lead to irreversible effects for post-metamorphic animals and are related to inferior competitive abilities.
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PMID:Strong influences of larval diet history on subsequent post-settlement growth in the freshwater mollusc Dreissena polymorpha. 1239 85

Dual channel imaging and warping of two-dimensional (2D) protein gels were used to visualize global changes of the gene expression patterns in growing Bacillus subtilis cells during entry into the stationary phase as triggered by glucose exhaustion. The 2D gels only depict single moments during the cells' growth cycle, but a sequential series of overlays obtained at specific points of the growth curve facilitates visualization of the developmental processes at the proteomics scale. During glucose starvation a substantial reprogramming of the protein synthesis pattern was found, with 150 proteins synthesized de novo and cessation of the synthesis of almost 400 proteins. Proteins induced following glucose starvation belong to two main regulation groups: general stress/starvation responses induced by different stresses or starvation stimuli (sigma(B)-dependent general stress regulon, stringent response, sporulation), and glucose-starvation-specific responses (drop in glycolysis, utilization of alternative carbon sources, gluconeogenesis). Using the dual channel approach, it was not only possible to identify those regulons or stimulons, but also to follow the fate of each single protein by the three-color code: red, newly induced but not yet accumulated; yellow, synthesized and accumulated; and green, still present, but no longer being synthesized. These green proteins, which represent a substantial part of the protein pool in the nongrowing cell, are not accessible by using DNA arrays. The combination of 2D gel electrophoresis and MALDI TOF mass spectrometry with the dual channel imaging technique provides a new and comprehensive view of the physiology of growing or starving bacterial cell populations, here for the case of the glucose-starvation response.
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PMID:Bacillus subtilis during feast and famine: visualization of the overall regulation of protein synthesis during glucose starvation by proteome analysis. 1256

The harsh life in the ghettos were characterized by overcrowding, shortage of supplies (e.g. money, sanitation, medications), poor personal hygiene, inclement weather and exhaustion. Under these conditions, morbidity was mainly due to infectious diseases, both endemic and epidemic outbreaks with a high mortality rate. The dominant feature was hunger. Daily caloric allowance was 300-800, and in extreme cases (i.e. Warsaw ghetto) it was only 200 calories. The food was lacking important nutrients (e.g. vitamins, trace elements) leading to protean clinical expression, starvation and death. The clinical manifestations of starvation were referred to as "the Hunger Disease", which became the subject of research by the medical doctors in the ghettos, mainly in the Warsaw ghetto in which a thorough documentation and research were performed. The first victims of hunger were children. First they failed to thrive physically and later mentally. Like their elders, they lost weight, but later growth stopped and their developmental milestones were lost with the loss of curiosity and motivation to play. The mortality rate among babies and infants was 100%, as was described by the ghetto doctors: "when the elder children got sick, the small ones were already dead...". In the last weeks of the ghettos there were no children seen in the streets. In this article the environmental conditions and daily life of children in the ghettos are reviewed, and the manifestations of "Hunger Disease" among them is scrutinized.
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PMID:[Clinical manifestations of "Hunger Disease" among children in the ghettos during the Holocaust]. 1280 57

In Saccharomyces cerevisiae the transition between the fermentative and the oxidative metabolism, called the diauxic shift, is associated with major changes in gene expression. In this study, we characterized a novel family of five genes whose expression is induced during the diauxic shift. These genes, FET3, FTR1, TIS11, SIT1, and FIT2, are involved in the iron uptake pathway. We showed that their induction at the diauxic shift is positively controlled by the Snf1/Snf4 kinase pathway. The transcriptional factor Aft1p, which is known to control their induction in response to iron limitation, is also required for their induction during the diauxic shift. The increase of the extracellular iron concentration does not affect this induction, indicating that glucose exhaustion by itself would be the signal. The possibility that the Snf1/Snf4 pathway was also involved in the induction of the same set of genes in response to iron starvation was considered. We demonstrate here that this is not the case. Thus, the two signals, glucose exhaustion and iron starvation, use two independent pathways to activate the same set of genes through the Aft1p transcriptional factor.
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PMID:The Snf1 protein kinase controls the induction of genes of the iron uptake pathway at the diauxic shift in Saccharomyces cerevisiae. 1296 Jan 68

The transcriptome of a wine yeast was monitored throughout an alcoholic fermentation under conditions mimicking an enological environment. Major changes in gene expression occurred during fermentation, affecting more than 2000 genes, as the yeast adapted to changing nutritional, environmental and physiological conditions. The genes of many pathways are regulated in a highly coordinated manner, and genes involved in the key metabolic pathways of fermentation are strongly expressed. We showed that, during fermentation of a synthetic medium mimicking a natural must in which growth arrest was caused by nitrogen exhaustion, entry into the stationary phase triggered major transcriptional reprogramming. Many TOR target genes involved in nitrogen utilization or other functions are induced at this stage, suggesting that this signalling pathway plays a critical role in changes in gene expression in response to nitrogen depletion. Entry into stationary phase is a key physiological event and is followed by a general stress response. The superimposition of multiple stresses, including starvation and ethanol stress, gives rise to a unique stress response, involving hundreds of genes encoding proteins involved in various cellular processes, many of unknown function.
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PMID:Genome-wide monitoring of wine yeast gene expression during alcoholic fermentation. 1466 29

Lactococcus lactis strain NZ9000(pNZpyk), which overproduces pyruvate kinase (PK), was constructed. The pNZpyk plasmid carries the P(nisA)-pyk transcriptional fusion, and the overexpression of its pyk gene was accomplished by using the nisin-inducible expression system of the NZ9000 strain. In vivo (13)C- and (31)P-NMR spectroscopy was used to evaluate the effect of this modification on the metabolism of glucose in non-growing cells. A detailed description of the kinetics of glucose, end products, glycolytic intermediates, NAD(+) and NADH was obtained. A 15-fold increase in the level of PK did not increase the overall glycolytic flux, which, on the contrary, was slightly reduced. Significant differences were observed in (i) the level of 3-phosphoglycerate (3-PGA) and phosphoenolpyruvate (PEP), metabolites associated with starvation; (ii) the rate of fructose 1,6-bisphosphate (FBP) depletion upon glucose exhaustion; and (iii) the NAD(+)/NADH ratio during glucose catabolism. In the mutant, the rate of FBP consumption after glucose depletion was notably accelerated under anaerobic conditions, whereas 3-PGA and PEP decreased to undetectable levels. Furthermore, the level of NAD(+) decreased steadily during the utilization of glucose, probably due to the unanticipated reduction in the lactate dehydrogenase activity in comparison with the control strain, NZ9000(pNZ8020). The results show that PK is an important bottleneck to carbon flux only when glucose becomes limiting; in the overproducer this constriction was no longer present, as evidenced by the faster FBP consumption and lack of accumulation of 3-PGA and PEP in anaerobic as well as aerobic conditions. Despite these clear changes, the PK-overproducing strain showed typical homolactic metabolism under anaerobic conditions, as did the strain harbouring the vector plasmid without the pyk insert. However, under an oxygen atmosphere, there was increased channelling of carbon to the production of acetate and acetoin, to the detriment of lactate production.
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PMID:Effect of pyruvate kinase overproduction on glucose metabolism of Lactococcus lactis. 1507 20

Using a combined quantitative proteomic and bioinformatic approach, we monitored the cytoplasmic proteome profile of the Gram-positive bacterium Bacillus subtilis during a fermentation process in complex medium. Proteome signatures were applied to elucidate the physiological changes occurring in the gene expression profile during growth. Furthermore, we determined the significance level of quantitative proteome changes, identified relative to the threshold of scatter in replicated samples and developed a statistically rigorous method that allowed us to determine significant fold-changes at 95% confidence between different proteomes. Different functional groups of proteins were clustered according to their pattern of significant expression changes. The largest group is induced by the exhaustion of glucose and the presence of alternative carbon and nitrogen sources. Furthermore, depletion of glucose caused the induction of the trichloroacetic acid (TCA) cycle enzymes and the downregulation of glycolytic enzymes. The onset of the transition phase may be provoked by amino acid starvation, resulting in the RelA-dependent repression of proteins involved in the translation process and in the induction of amino acid biosynthetic pathways. Comparisons between the parental strain and two subtilisin-hypersecreting strains revealed only small cytoplasmic differences in the main metabolic pathways. Instead, the overproduction of degradative enzymes in both of these mutants was reflected in the extracellular proteome.
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PMID:Quantitative proteome profiling during the fermentation process of pleiotropic Bacillus subtilis mutants. 1527 36

Transcription of the catabolic touABCDEF operon, encoding the toluene-o-xylene monooxygenase of Pseudomonas stutzeri OX1, is driven by the sigma(54)-dependent Ptou promoter, whose activity is controlled by the phenol-responsive NtrC-like activator TouR. In this paper we describe for the first time a peculiar characteristic of this system, namely, that Ptou transcription is activated in a growth phase-dependent manner in the absence of genuine effectors of the cognate TouR regulator. This phenomenon, which we named gratuitous activation, was observed in the native strain P. stutzeri OX1, as well as in a Pseudomonas putida PaW340 host harboring the reconstructed tou regulatory circuit. Regulator-promoter swapping experiments demonstrated that the presence of TouR is necessary and sufficient for imposing gratuitous activation on the Ptou promoter, as well as on other sigma(54)-dependent catabolic promoters, whereas the highly similar phenol-responsive activator DmpR is unable to activate the Ptou promoter in the absence of effectors. We show that this phenomenon is specifically triggered by carbon source exhaustion but not by nitrogen starvation. An updated model of the tou regulatory circuit is presented.
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PMID:TouR-mediated effector-independent growth phase-dependent activation of the sigma54 Ptou promoter of Pseudomonas stutzeri OX1. 1548 47

Adaptation of Lactococcus lactis towards progressive carbon starvation is mediated by three different types of transcriptomic responses: (i) global responses, i.e., general decreases of functions linked to bacterial growth and lack of induction of the general stress response; (ii) specific responses functionally related to glucose exhaustion, i.e., underexpression of central metabolism genes, induction of alternative sugar transport and metabolism, and induction of the arginine deiminase pathway; and (iii) other responses never described previously during carbon starvation.
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PMID:Transcriptome analysis of the progressive adaptation of Lactococcus lactis to carbon starvation. 1586 50

The stability of mRNA was investigated for the first time at the genomic scale during carbon starvation adaptation of Lactococcus lactis IL1403. In exponential phase, mRNA half-lives were correlated positively to open reading frame length. A polypurine sequence, AGGAG, was identified as a putative 5'-stabilizer and inverted repeated sequences as a 3'-destabilizer. These original findings suggested that multiple pathways of mRNA degradation should coexist: internal cleavage, endonuclease cleavage initiated at the 5'-end, and exonuclease attack at the 3'-end. During carbon starvation adaptation, mRNA stability globally increased, but specific mechanisms allowing a wide range of stabilization factors between genes and differential kinetic evolution were involved. A formal method allowing the quantification of the relative influences of transcription and degradation on the mRNA pool control was developed and applied in L. lactis. Gene expression was mostly controlled by altered transcription prior to carbon source exhaustion, while the influence of mRNA stability increased during the starvation phase. This study highlighted that stability modulation in response to adverse growth conditions can govern gene regulation to the same extent as transcription in bacteria.
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PMID:Role of mRNA stability during genome-wide adaptation of Lactococcus lactis to carbon starvation. 1613 90


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