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

Oral administration of manganese to young rats results in poorly mineralized primary spongiosa and an irregularly thickened growth plate with a histologic resemblance to that in vitamin D-deficiency rickets. In the present study, the rachitic lesions were characterized by stereologic methods at the light microscopic level. With increasing doses of Mn in the diet, the animals developed rachitic lesions of increasing severity, i.e., the total height of the growth plate and the relative volume of the hypertrophic zone increased. The experimental animals developed hypophosphatemia, which was dependent on the Mn dose. The observed serum concentrations of Mn and phosphorus are compatible with the idea that MnHPO4 is precipitated in the gut, leaving only small amounts of Mn and phosphate available for absorption. Furthermore, the severity of the rachitic lesions were inversely correlated to the concentration of phosphate in serum. The most important pathomechanism in Mn rickets is phosphate depletion, which per se causes similar rachitic changes, even though Mn also seems to have other effects. Starvation caused a decrease in the height of the growth plate and in the volume fraction of the hypertrophic zone, thus changes contrary to the rachitic lesions.
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PMID:The effect of manganese ingestion, phosphate depletion, and starvation on the morphology of the epiphyseal growth plate. A stereologic study. 401 42

1. Mg(2+) or Mn(2+) starvation causes suspensions of Bacillus subtilis strain W 23 to accumulate bound amino sugars that are soluble in trichloroacetic acid. 2. The presence of chloramphenicol or puromycin produces higher intracellular concentrations of amino sugars during Mg(2+) starvation, but neither compound can stimulate the accumulation when Mg(2+) is present. 3. The major component of the amino sugar fraction extracted from cells deprived of Mg(2+) is a nucleotide containing uridine, phosphorus, N-acetylmuramic acid, alanine, glutamic acid and alphain-diaminopimelic acid in the molar proportions of 1:2:1:3:1:1. This compound represents at least 80% of the bound N-acetylhexosamine extracted by trichloroacetic acid. 4. Studies of the binding of this nucleotide with vancomycin support the proposal that it is the mucopeptide precursor UDP-N-acetylmuramyl-l-alanyl-d-glutaminyl- alphain-diaminopimelyl-d-alanyl-d-alanine. 5. A method is described for the isolation of this material labelled with [(3)H]alphain-diaminopimelic acid. 6. When Mg(2+) is supplied to cells previously starved of Mg(2+), the accumulated pool of amino sugars rapidly decreases. 7. The biosynthesis of mucopeptide is inhibited by 35-50% under conditions of Mg(2+) starvation. The presence of EDTA increases this inhibition to 70%. The amount of N-acetylhexosamine that accumulates is balanced exactly by the associated fall in mucopeptide synthesis. 8. ;Chase' experiments show that the accumulated N-acetylhexosamine compound is utilized in mucopeptide synthesis.
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PMID:The effect of magnesium ion deprivation on the synthesis of mucopeptide and its precursors in Bacillus subtilis. 498 84

1. Methods are described for the extraction of lipid and assay of mono-, di- and tri-glyceride glycerol and phospholipid phosphorus in rat heart and gastrocnemius muscles. 2. In hearts from normal animals, concentrations found were: monoglyceride, 0.6; diglyceride, 0.1; triglyceride, 12.6mumoles of glyceride glycerol/g. of dry muscle; phospholipid, 171mug.atoms of phospholipid phosphorus/g. of dry muscle. Concentrations of glycerides in gastrocnemius muscle were similar to heart muscle but those of phospholipids were lower (64mug.atoms of phospholipid phosphorus/g. of dry muscle). 3. Alloxan-diabetes increased the concentration of triglyceride in the muscles twofold. This increase was shown to be dependent in the heart on the availability of growth hormone and cortisol but not on the availability of dietary lipid. Total glyceride in the heart was increased after 48 and 72hr. starvation but not after 96hr. Changes in glyceride concentration seen in starvation and diabetes were not associated with significant changes in phospholipid concentration. It is suggested that mobilization of free fatty acids in diabetes leads to the synthesis of additional glyceride in muscle. 4. The possible contribution of glyceride fatty acid in the heart to respiration during perfusion has been calculated from the net loss of glyceride during perfusion, and also from the relative rates of lipolysis and esterification and compared with oxidation of fatty acid required for the balance of oxygen consumption (oxygen not utilized in the oxidation of glucose or glycogen glucose). In the normal or diabetic heart perfused with glucose and insulin the breakdown of glyceride can account for the balance of oxygen consumption. In the normal heart perfused without substrate the balance of oxygen consumption is not entirely accounted for by the breakdown of glyceride.
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PMID:Concentrations of glycerides and phospholipids in rat heart and gastrocnemius muscles. Effects of alloxan-diabetes and perfusion. 604 83

Renal phosphate (Pi) wastage following 7 days of starvation was investigated in normal rats (HI-P) and others previously stabilized on a low phosphorus (LO-P)diet. In LO-P animals, Pi excretion increased after starvation, but was significantly less than in starved HI-P rats. After thyroparathyroidectomy, the increase in Pi excretion after parathyroid hormone (PTH) was significantly greater in nonacidotic starved HI-P rats than in LO-P animals. However, PTH elicited a 31-fold increase in Pi excretion in both of these groups. Starved LO-P and HI-P rats responded equivalently to dibutyryl cyclic AMP. The renal response to phosphate depletion normally promotes Pi conservation, but is attenuated markedly by 7 days of subsequent starvation. This results from at least partial restoration of phosphaturic responsiveness to PTH during starvation.
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PMID:Interactions of starvation and selective phosphorus depletion on renal phosphate reabsorption. 628 63

A colorimetric method for the determination of lipid phosphorus in the nanomolar range was used to determine the total phospholipid content of isolated pancreatic islets. Freshly isolated islets of lean C57BL/6J mice contained significantly more phospholipids expressed per micrograms DNA as compared to C57BL/6J (ob/ob) mouse or Wistar rat islets. Starvation for 48 h (Wistar rats) or 60 h (NMRI mice) did not affect the islet phospholipid content. Phosphatidylcholine was the most abundant phospholipid class of NMRI mouse islets, followed by phosphatidylethanolamine, sphingomyelin, phosphatidylinositol, phosphatidylserine and lysophosphatidylcholine. When islets of NMRI mice were maintained for 5-7 days in tissue culture, the phospholipid content remained unchanged as compared to that of freshly isolated islets despite a considerable loss of the insulin stores. The islet phospholipid content was significantly increased when the glucose concentration of the culture medium was elevated from 3 to 28 mM. Leucine (10 mM) added to a low-glucose medium failed to increase the islet phospholipid content. Addition of glipizide (2 microM) to the culture medium decreased the islet insulin content significantly but failed to affect the total islet phospholipid content. Culture in a Ca2+-free medium containing 28 mM glucose increased the islet insulin content but, again, the phospholipid content remained unaffected. These data show that changes of the total phospholipid content of pancreatic islets are unrelated to the islet insulin content and presumably also to the content of secretory granules. Alterations of the islet content of phospholipids may rather reflect changes of the amount of endoplasmic reticulum of the islet cells.
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PMID:Effects of starvation and different culture conditions on the phospholipid content of isolated pancreatic islets. 639 54

At least 78%, and perhaps all, of inorganic polyphosphate is shown to be contained within the vesicles (vacuoles) of Neurospora crassa, where over 97% of the soluble arginine, lysine, and ornithine pools are known to accumulate. Furthermore, synthetic polyphosphate can concentrate arginine up to 400-fold from dilute (0.01 mM) solutions in equilibrium dialysis. For these reasons and because the molar ratio of basic amino acids and polyphosphate phosphorus is approximately 1, we tested the hypothesis that there was an obligate physiological relationship between them. Experiments in which nitrogen starvation and arginine excess were imposed upon cells showed that polyphosphate content was insensitive to changes in the basic amino acid content. Experiments involving phosphate starvation and restoration showed that basic amino acid content was almost wholly independent of polyphosphate pools. Moreover, the normal high degree of compartmentation of arginine in vesicles was maintained despite polyphosphate depletion, and arginine was still exchanged across the vesicular membrane. We conclude that N. crassa, like yeasts, can regulate polyphosphates and basic amino acids independently, and that the accumulation of basic amino acids in vesicles may depend upon an energy-requiring mechanism in addition to the demonstrated charge interaction with polyphosphate.
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PMID:Basic amino acids and inorganic polyphosphates in Neurospora crassa: independent regulation of vacuolar pools. 644 98

The Leeds facility for in vivo neutron activation analysis has been modified and calibrated for the simultaneous measurement of nitrogen, potassium, sodium, chlorine, phosphorus and calcium in obese patients weighing up to 210 kg. The effects of body size and shape were incorporated into the calibration by measuring 14 anthropomorphic phantoms of known composition representing individual patients being treated for obesity. The phantoms were constructed from tissue substitutes representing lean, skeletal and adipose tissues, arranged to simulate the distributions of the corresponding tissues within the patients, as visualised by CT scanning. The precision of the method, determined by measuring a single phantom ten times over a period of ten weeks, is between two and three per cent for all elements except calcium, for which it is 11.3%. Accuracy is estimated to be similar to precision. The procedure has been used to study changes in body composition of patients undergoing therapeutic starvation.
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PMID:Multi-element analysis of the obese subject by in vivo neutron activation analysis. 646 4

The effect of a number of conditions on the amount of cyanophycin granule polypeptide [multi-L-arginyl poly(L-aspartic acid)] formed in the unicellular cyanobacterium Aphanocapsa 6308 was determined. Light, CO2, sulfur, and phosphorus starvation as well as the addition of arginine to culture media increased the amount of cyanophycin granule polypeptide in cells when compared with that in cells grown under conditions optimal for growth. Nitrogen limitation and reduction of growth temperature to 30 degrees C decreased the amount of cyanophycin granule polypeptide on a dry-weight basis. Shift-up and shift-down experiments suggest cyanophycin granule polypeptide may be a reserve nitrogen polymer in Aphanocapsa 6308.
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PMID:Cyanophycin granule polypeptide formation and degradation in the cyanobacterium Aphanocapsa 6308. 676 88

The localization of alkaline phosphomonoesterase (EC 3.1.3.1) was studied in two Pseudomonas species: P. maltophilia VKM B-591 and P. aeruginosa VKM B-889. The former species is characterized by constitutive synthesis of alkaline phosphatase, and its level is not regulated by orthophosphate in the medium. The enzyme of the latter species is orthophosphate-repressible. The two species differ also in the localization of the enzyme in the cell. Under the conditions of derepression (the absence of inorganic phosphate from the medium), the enzyme of the repressible strain of P. aeruginosa is actively synthesized on the membranes and secreted into the medium. Most of the enzyme activity (80--90%) is found in the cultural broth 4 h after phosphorus starvation. In P. maltophilia, 90% of the synthesized enzyme is found in the membrane fraction irrespective of the incubation time under the same conditions. Apparently, a correlation exists between the regulation of alkaline phosphatase synthesis and the localization of the enzyme. It is likely that in P. aeruginosa, just as in E. coli, alkaline phosphatase is synthesized on polysomes attached to the membrane, with the subsequent translocation of the enzyme to the site of its localization. P. maltophilia appears to have a defect in one of its membrane component responsible for the regulation of the synthesis and the secretion of the enzyme in the cell.
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PMID:[Relationship of Pseudomonas maltophilia alkaline phosphatase to its membranes]. 679 9

We report that Chinese hamster ovary cells assemble membrane phospholipids from choline-linked lipid present in fetal calf serum. This was examined by testing the ability of various serum preparations to satisfy the choline requirement of the cells. Chinese hamster ovary cells divided in growth medium containing lipoprotein-deficient serum and approximately 8 microM lysolecithin. Identical results were obtained in growth medium supplemented with solvent-extracted (delipidated) serum reconstituted with purified egg lysolecithin and the uptake of lipid was inhibited by the addition of bovine serum albumin. Analysis of the phospholipid composition of cells incubated with 32Pi and egg lysolecithin in place of choline revealed that approximately 30% of the phosphorus moieties of the cellular phospholipids were derived from the added lipid, while in the presence of choline less than 10% arose in this fashion. Choline starvation enhanced the formation of lecithin from [32P]lysolecithin without affecting phospholipid turnover and labeled lecithin was converted to other phospholipids, especially sphingomyelin and phosphatidylserine. Unlike endogenous serum lysolecithin, lipoproteins obtained from human and fetal calf sera failed to satisfy the choline requirement of Chinese hamster ovary cells, even though 95% of the lipoprotein phospholipid was phosphatidylcholine and sphingomyelin. Together, these results demonstrate that animal cells can derive all of the choline required for membrane phospholipid synthesis from serum lysolecithin and that its conversion to lecithin within the cell is regulated by the availability of choline. In contrast, serum lipoproteins do not normally serve as a major source of choline moieties.
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PMID:Biosynthesis of phosphatidylcholine from serum phospholipids in Chinese hamster ovary cells deprived of choline. 682 51


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