Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ugp operon of Escherichia coli includes genes involved in the uptake of sn-glycerol-3-phosphate and glycerophosphoryl diesters and belongs to the pho regulon which is induced by phosphate limitation. This operon has two transcriptional initiation sites, as determined by S1 nuclease mapping of the in vivo transcripts. The downstream promoter has multiple copies of the pho box, the consensus sequence shared by the pho promoters; the upstream promoter has a consensus sequence for the promoters regulated by cyclic AMP and its receptor protein, CRP. PhoB protein, which is the transcriptional activator for the pho regulon, protected the regulatory region with the pho boxes in DNase I footprinting experiments and activated transcription from the downstream promoter in vitro. Studies with transcriptional fusions between ugp and a promoterless gene for chloramphenicol acetyltransferase show that the upstream promoter is induced by carbon starvation in a manner that required the cya and crp genes. PhoB protein may act as a repressor for this upstream promoter, which also overlaps the upstream third pho box. The downstream promoter was induced by phosphate starvation and requires the PhoB protein for its activation as do the other pho regulon promoters. These results suggest that the two promoters function alternately in responding to phosphate or carbon starvation, thus providing the cell with a means to adapt to these physiological stresses.
 ...
PMID:Dual regulation of the ugp operon by phosphate and carbon starvation at two interspaced promoters. 198 50

Low rates of triacylglycerol (TAG) biosynthesis were observed in cell-free extracts of Candida curvata, but rates were increased up to 10-fold by adding either alpha- or beta-cyclodextrins. Spheroplasts, whole or gently disrupted, had higher rates of incorporation of both [U-14C]glycerol 3-phosphate or [1-14C]oleate into triacylglycerol and the intermediates of its biosynthesis: lysophosphatic acid, phosphatidic acid and diacylglycerol. Fatty acyl-CoA synthetase was highest with palmitate, oleate and linoleate but was some 6- to 8-fold lower with stearate. Stearate and stearoyl-CoA were poorly incorporated into lipids. Subcellular fractionation of the spheroplasts into mitochondrial, microsomal, lipid bodies and supernatant fractions diminished the rates of 14C incorporation of oleate into triacylglycerol. By comparing the relative specific activities for each activity in each fraction, the fatty acyl-CoA synthetase activity appeared mainly in the lipid bodies, and that for phosphatidic acid formation was mainly in the mitochondrion; other activities were too weak and too dispersed for accurate assessment of their location. Recombining all the subcellular fractions restored triacylglycerol synthesizing activity. Omitting any single fraction from the mixture did not result in restoration of triacylglycerol synthesizing activity. Starvation of the yeast, which leads to utilization of the endogenous lipid reserves, stimulated fatty acyl-CoA synthetase activity, but diminished phosphatidic acid and triacylglycerol biosynthesis indicating probable induction of beta-oxidation in the peroxisomes and repression of lipid biosynthesis.
 ...
PMID:Triacylglycerol synthesis in the oleaginous yeast Candida curvata D. 205 92

Female rats were mated and thyroidectomized on the same day. Some animals were kept without treatment and killed on day 12 or 21 of gestation (T). Others were subsequently treated daily with 1.8 micrograms L-T4/100 g BW for either the first 12 days and then not treated from that time until day 21 [T+T4(I+0)] or else not treated for the first 12 days and then treated from days 12-21 [T+T4(0+II)]. A final group received treatment during the entire 21-day study [T+T4(I+II)] and was used as the control. The net maternal body weight increased until day 12 of gestation in T+T4(I+II) rats, but not in T animals. On day 21 net maternal body weight was significantly lower in T and T+T4(0+II) than in T+T4(I+II) rats. Lipoprotein lipase activity in the lumbar fat pads increased from days 0 to 12 of gestation and decreased on day 21, whereas in the heart the change was in the opposite direction, and these changes were greater in T+T4(I+II) rats than in T rats. Incorporation of [U-14C]glucose administered in vivo into liver [14C]fatty acids or [14C]glycogen was significantly lower in T rats than in T+T4(I+II) on either the 12th or 21st day of gestation. The response of plasma triglyceride, glycerol, or beta-hydroxybutyrate levels to 24 h of starvation was similar in 12-day pregnant rats regardless of whether they were treated with T4, whereas on day 21 the change was greater in T+T4(I+II) or T+T4(I+0) animals than in T or T+T4(0+II) animals. Results show that maternal hypothyroidism during the first half of gestation impaired the anabolic events occurring during this phase and compromised the normal catabolic response during late gestation even when T4 treatment was restored. However, once maternal metabolic stores were built up normally during the first half of gestation, maternal hypothyroidism during late gestation did not affect the mother's normal metabolic adaptation, including the accelerated response to starvation.
 ...
PMID:Maternal hypothyroidism during the first half of gestation compromises normal catabolic adaptations of late gestation in the rat. 205 83

Twenty-four independent phosphate starvation-inducible (psi) transcriptional fusions made with Mu d1(lacZbla) were analyzed by sequencing the psi::lacZ(Mu d1) chromosomal junctions by using DNAs amplified with the polymerase chain reaction or mini-Mu cloning. Our DNA sequence analysis showed that the MuR DNA in Mu d1 has an unexpected structure that is comprised of 104 bases of MuR DNA in the form of a large inverted repeat, which we denoted Mu d1-R. Also, Mu d1s in the phoA and phn (psiD) loci of the phosphate regulon showed regional specificities for the insertion sites despite the randomness of Mu d1 insertions into the genome as a whole. Gene products or open reading frames were identified for seven unknown psi::lacZ(Mu d1) transcriptional fusions by searching DNA data bases with the sequences adjacent and upstream of the Mu d1s. One psiC::lacZ(Mu d1) lies in the ugpB gene of the ugpBAEC operon, which encodes a periplasmic sn-glycerol-3-phosphate-binding protein; two psiQ::lacZ(Mu d1)s lie in the gltB gene, and one psiQ::lacZ(Mu d1) lies in the gltD gene of the gltBDF operon, encoding the large and small subunits of glutamate synthase, respectively; and the psi-51::lacZ(Mu d1) lies in the glpB gene of the glpABC operon, which codes for the anaerobically regulated glycerol-3-phosphate dehydrogenase. psiE and psiF::lacZ(Mu d1)s lie in uncharacterized open reading frames near the xylE and phoA genes, respectively. Six other psi::lacZ(Mu d1)s lie in yet unreported Escherichia coli sequences.
 ...
PMID:Identification of phosphate starvation-inducible genes in Escherichia coli K-12 by DNA sequence analysis of psi::lacZ(Mu d1) transcriptional fusions. 216 Sep 40

Because of the highly conserved pattern of expression of the eucaryotic heat shock genes hsp70 and hsp84 or their cognates during sporulation in Saccharomyces cerevisiae and development in higher organisms, the role of the Escherichia coli homologs dnaK and htpG was examined during the response to starvation. The htpG deletion mutant was found to be similar to its wild-type parent in its ability to survive starvation for essential nutrients and to induce proteins specific to starvation conditions. The dnaK103 mutant, however, was highly susceptible to killing by starvation for carbon and, to a lesser extent, for nitrogen and phosphate. Analysis of proteins induced under starvation conditions on two-dimensional gels showed that the dnaK103 mutant was defective for the synthesis of some proteins induced in wild-type cells by carbon starvation and of some proteins induced under all starvation conditions, including the stationary phase in wild-type cells. In addition, unique proteins were synthesized in the dnaK103 mutant in response to starvation. Although the synthesis of some proteins under glucose starvation control was drastically affected by the dnaK103 mutation, the synthesis of proteins specifically induced by nitrogen starvation was essentially unaffected. Similarly, the dnaK103 mutant was able to grow, utilizing glutamine or arginine as a source of nitrogen, at a rate approximate to that of the wild-type parent, but it inefficiently utilized glycerol or maltose as carbon sources. Several differences between the protein synthetic pattern of the dnaK103 mutant and the wild type were observed after phosphate starvation, but these did not result in a decreased ability to survive phosphate starvation, compared with nitrogen starvation.
 ...
PMID:Role of Escherichia coli heat shock proteins DnaK and HtpG (C62.5) in response to nutritional deprivation. 225 78

The time course of plasma substrate level alterations in the tumor-bearing (TB) host and their relationship to tumor burden or weight loss has not been well defined. Plasma glucose, lactate, pyruvate, cholesterol, triglycerides, acetoacetate, beta-hydroxy butyrate, and glycerol levels were measured in postabsorptive TB and nontumor-bearing (NTB) male Fisher 344 rats at weekly intervals for 5 weeks. Chronically starved rts (CS) had plasma substrates measured at Week 3 and compared with TB and NTB levels. Tumor burden was 0.5% of body weight at Week 1, 3.5% at Week 2, 12% at Week 3, and 20% at Week 5. Glucose levels were significantly lower in TB versus NTB (P = 0.01) at Week 1 and progressively declined in TB versus NTB through Week 5 (P less than 0.001). At Week 2, plasma triglycerides, cholesterol, acetoacetate, and beta-hydroxy butyrate were significantly elevated in TB versus NTB (P less than 0.001) and increased further to Week 5. The profile of substrate changes in TB and CS, when compared to NTB rats at Week 3, were different, suggesting that the plasma substrate alterations seen in the TB state were not secondary to starvation. In addition, when tumors were excised from TB animals at Week 3 and plasma substrates were determined 1 week later, all substrates that were different between TB and NTB animals, except cholesterol, returned to NTB levels when compared to sham-operated controls.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Substrate alterations in a sarcoma-bearing rat model: effect of tumor growth and resection. 235 23

The effects of 48-h starvation on the physiological responses to a 30-min infusion of epinephrine at 25 ng.min-1.kg body wt-1 were studied in 11 normal-weight healthy young subjects. Starvation led to considerable alterations in basal metabolism including a significant (mean 3.6%) increase in resting metabolic rate. During the infusions, plasma epinephrine concentration rose less in the starved state (+1.47 nmol/l) than in the normally fed state (+1.73 nmol/l) (SE 0.06 nmol/l; P less than 0.05). The maximum increments (mean +/- SE) in heart rate induced by epinephrine were 11.9 +/- 1.3 beats/min in the normally fed state and 20.1 +/- 2.0 beats/min in the starved state (P less than 0.001); the corresponding mean increments in blood glycerol concentration were 0.07 and 0.14 mmol/l (SE 0.01 mmol/l; P less than 0.01). The increase in the metabolic rate above base line during the final 10 min of the epinephrine infusion was 0.58 +/- 0.18 kJ/min in the normally fed state and 0.78 +/- 0.14 kJ/min in the starved state (P less than 0.01). The chronotropic, lipolytic, and thermogenic effects of infused epinephrine were therefore enhanced by prior starvation, despite the lower plasma epinephrine levels.
 ...
PMID:Enhanced thermogenic response to epinephrine after 48-h starvation in humans. 240 17

We have determined the blood metabolite responses to a 24-h starvation period of cafeteria obese rats, in both non-pregnant and late pregnant states. In the fed condition the concentrations of glucose, lactate, pyruvate, glycerol and urea do not differ when compared in control and obese rats, but acetoacetate and 3-hydroxybutyrate levels are higher in the obese group. The overall response of the cafeteria-obese rats to starving seems characterized by decreased rates of glucose and amino-acids utilization, substituted by a more intense utilization of lipid fuels, with excess ketone bodies production and increased utilization of the mobilized glycerol. What we observed in the obese pregnant response to starvation can be summarized as the additional or superimposed effects of excess fat reserves. In the obese pregnant starved rats a less severe hypoglycaemia, lower levels of glycerol (as a consequence of increased utilization), reduced urea levels, and increased acetoacetate and 3-hydroxybutyrate levels were observed. It can be assumed that the pregnant obese rat response to starvation is related to the size of the fat deposits: the more obese, the more hyperketonaemia and less hypoglycaemia, and even diminished rates of amino-acid utilization, as indicated by a lower levels, when compared to the lean pregnant.
 ...
PMID:Metabolic response to short term starvation in non-pregnant and late pregnant cafeteria-obese rats. 247 87

dsg mutants of Myxococcus xanthus are conditionally defective in fruiting body development, including sporulation. Unable to develop on their own, these mutants can assemble fruiting bodies with spores if they are mixed with wild-type cells. To elucidate the developmental defect in dsg mutants by close comparison with wild type, such mutants have been backcrossed by transduction, using a closely linked insertion of transposon Tn5 for selection. Backcrossed dsg mutants form aggregates that are larger, less compact, and less symmetrical than dsg+ fruiting bodies. Also, the starvation-induced sporulation in dsg aggregates is delayed and reduced. However, dsg mutants can be induced by glycerol or dimethyl sulfoxide to sporulate at levels approaching those of wild type. dsg mutants may thus have a primary defect early in development which diminishes their capacity to aggregate and which indirectly decreases the number of fruiting body spores. The linked insertion of Tn5 also facilitated cloning the dsg gene. The cloned dsg+ allele was shown to be dominant to both the dsg-429 and dsg-439 alleles, and both mutant alleles were shown to belong to the same genetic complementation group. Subcloning of restriction fragments, deletions, and insertions of transposon Tn5 agree in locating the dsg gene to an 850-base-pair segment of the cloned region.
 ...
PMID:dsg, a gene required for cell-cell interaction early in Myxococcus development. 254 52

In order to advise regarding the religious practice of withholding food, we studied the metabolic changes after successive 15 days of recurrent fasting of 13 hours every day in maternal plasma and liquor amnii of obese normal gravids and gestational diabetics in their third trimester. There were no significant differences between those who fasted that period for one day prior to elective cesarean section (CS) and those who fasted the same period repeatedly for 15 days. The fasted gravids had significant rises in glycerol, beta-hydroxybutyrate (BOHB) and nonesterified fatty acids (NEFA) (P less than 0.0001, P less than 0.005 and P less than 0.01, respectively) in maternal plasma, compared to unfasted gravid groups and ungravid fasted group. No significant metabolic difference was found in the liquor amnii withdrawn from fasted and unfasted groups. The influence of such short term of starvation on the fetal metabolic profile was studied in the cord blood during cesarean section (CS). Glucose, glycerol and NEFA were significantly lower in arterial than in venous cord plasma (P less than 0.05, P less than 0.01 and P less than 0.01, respectively) indicating that the fetus could utilize these substrates. Positive correlation was found between the levels of BOHB in the mother and venous cord plasma on the one hand and their levels in the arterial cord plasma and liquor amnii on the other hand implying that this substrate passes unutilized through the fetus to the liquor amnii. A pregnant woman in the third trimester should not withhold food for long periods.
 ...
PMID:Maternal, amniotic fluid and cord blood metabolic profile in normal pregnant and gestational diabetics during recurrent withholding of food. 258 75


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>