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)

1. Clinical and necropsy observations in lepromatous leprosy associated with severe emaciation and accompanying hypoproteinemia suggest that protein deprivation may be of pathogenic significance in the ulcerative phenomenon that is designated "Lazarine leprosy". 2. An experimental utilizing Wiersung rats infected with Mycobacterium lepraemurium and maintained on a protein-free diet was developed for the purpose of studying the effect of protein starvation on the course of chronic mycobacterial disease similar to lepromatous leprosy with respect to pathogen and host inflammatory response. 3. It was possible to maintain the experimental animals on a protein-free diet for up to 18 weeks of concomitant M. lepraemurium infection. This was long enough for the infection to disseminate to a degree that was evident in control animals only several weeks later. 4. The protein-deprived animals showed decreased inflammatory response to the pathogen, presented more rapid dissemination of the infection and harbored more bacilli per macrophage than did animals similarly infected but maintained on a protein adequate diet. This indicates impairment of native cellular immunity by protein deprivation through decrease in ability of macrophages to inhibit bacillary multiplication. 5. There was no evidence of impairment of macrophage ability to phagocytose the pathogens. 6. Morphologically the increased dissemination of pathogens and decrease in inflammatory response was similar to the increase in number and extent of visceral lesions seen in Lazarine leprosy. Decreased ability to dispose of the infecting bacilli was similar in the two models, human and animal. The animal model does not, as does lepromatous leprosy, involve the skin in the infection. Hence comparable ulcerative phenomena were not replicated in the animals. 7. It is suggested that Lazarine leprosy may result from enhanced lepromatous leprous infection occurring as a result of protein malnutrition. The pathogenic mechanism appears to be impairment of cellular immunity probably enhanced by concomitant impairment of humoral antibody immunity resulting also in decreased resistance to pyogenic and other secondary pathogens. The tissue edema attendant on decreased serum osmotic pressure due to lowering of the serum protein fractions enhances the probability of ulceration.
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PMID:The role of protein malnutrition in the pathogenesis of ulcerative "Lazarine" leprosy. 82 11

Mycobactin patterns from 65 Mycobacterium fortuitum and Mycobacterium chelonae strains have been determined by thin-layer chromatography. By use of a rich liquid medium containing an iron chelator (ethylenediamine-di-o-hydroxyphenylacetic acid [EDDA]) to ensure iron starvation, all strains were able to form mycobactins. The method developed here allows sensitive detection of mycobactin by thin-layer chromatography from as little as 5 ml of culture after a 2-week incubation. Within M. fortuitum two mycobactin patterns were identified, whereas within M. chelonae four were recognized. Comparisons with the subspecific identification performed by using biochemical tests showed that 73% of the M. fortuitum subsp. fortuitum strains shared the same mycobactin pattern (designated F), whereas 75% of the M. fortuitum subsp. peregrinum strains shared the other mycobactin pattern (designated P). Within the M. fortuitum strains that cannot be assigned to a subspecies on the basis of their biochemical features, only F and P patterns were determined. Similarly, 93% of the M. chelonae subsp. chelonae strains produced the so-called C1 and C2 patterns and 86% of the M. chelonae subsp. abscessus strains produced A1 and A2 patterns. C2 and A2 were the patterns most frequently encountered; they were represented by 65 and 50% of the M. chelonae subsp. chelonae and M. chelonae subsp. abscessus strains, respectively. Within the biochemically M. chelonae strains that did not fit any subspecies on the basis of biochemical test results, C1, C2, and A1 patterns were found. Whereas about 30% of both M. fortuitum and M. chelonae strains cannot be characterized to the subspecies level on the basis of biochemical tests, 100% of the strains of both species can be characterized on the basis of mycobactin patterns.
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PMID:Mycobactin analysis as an aid for the identification of Mycobacterium fortuitum and Mycobacterium chelonae subspecies. 158 24

Protein antigen b (Pab) of Mycobacterium tuberculosis has previously attracted interest because of its immunological and diagnostic relevance. In this study we present evidence that Pab possesses a signal sequence and is secreted from the cytoplasm of M. tuberculosis. The synthesis of Pab is enhanced under phosphate starvation indicating that the protein is involved in phosphate metabolism in M. tuberculosis.
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PMID:Evidence that protein antigen b of Mycobacterium tuberculosis is involved in phosphate metabolism. 211 64

Ten cultures of Mycobacterium tuberculosis, one of Mycobacterium kansasii (nonsignificant), and one of Mycobacterium phlei were submitted to starvation. As a result they lost first their acid fastness and then all other staining affinities but, in this chromophobic state, they survived for at least 2 years and, after that time, produced cultures of acid-fast bacilli when transferred onto nutrient media. Chromophobic tubercle bacilli similar to those produced experimentally had previously been demonstrated in caseous lesions of lungs surgically removed from patients under chemotherapy. Since it has been shown that experimentally produced chromophobic bacilli can recover their original biological properties, the opinion is warranted that, under suitable conditions, those in the lung could also become reactivated and cause a relapse of the disease.
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PMID:Studies on the effect of starvation on mycobacteria. 413 10

Specific pathogen-free C57B1 mice are 100 to 1,000 times as sensitive as CD-1 mice to intravenous or oral challenge by Salmonella enteritidis or S. gallinarum. Resistance to infection by S. pullorum was unaffected. Growth of Listeria monocytogenes and Mycobacterium bovis (BCG) in intravenously infected C57B1 mice was similar to that seen in CD-1 mice. Quantitative counts of viable S. enteritidis in the walls of the stomach, small intestine, cecum, and large intestine and in the corresponding intestinal contents showed that most of the oral challenge inoculum was rapidly inactivated so that, by 24 hr, less than 1% was still viable. Overnight starvation and pretreatment with bicarbonate solution increased the relative survival of the challenge approximately 10-fold. Despite the rapid and extensive inactivation of the oral inoculum within the normal intestine, significant numbers of salmonellae reached the liver and spleen by 48 hr, and this systemic infection was subsequently responsible for the death of a high proportion of the challenged animals.
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PMID:Salmonellosis in orally infected specific pathogen-free C57B1 mice. 462 55

Mycobacterium avium, a facultative pathogen for humans, undergoes a life cycle in which selected small cells elongate and then fragment to form coccobacilli. M. avium cells of uniform size were selected by membrane filtration and tested for growth and division in the presence or absence of palmitic acid. Growth was measured by increased cellular protein, and cell division was determined by increased colony-forming units on agar or, electronically, by increased numbers of particles. Both growth and division rates of M. avium were found to be dependent upon the initial concentration of palmitic acid presented to the cells. The division constant varied from 0.05 to 0.13 when the concentration of palmitic acid ranged from 0 to 175 nmol/ml of medium. With [(14)C]palmitic acid as a tracer, it was found that rapid cell division began upon cessation of fatty acid uptake. During division, new lipid materials were released which contained (14)C derived from [(14)C]palmitic acid. Limited cell division and no fragmentation occurred in fatty acid-starved cultures. During fatty acid starvation, the transparent colony form, considered a pathogen, underwent a transition to the colony form considered a nonpathogen. The possible relationships between the organism's dependence on fatty acid and its ability to infect humans are discussed.
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PMID:Effect of palmitic acid utilization on cell division in Mycobacterium avium. 481 62

A gene encoding a protein homologous to the periplasmic ABC phosphate binding receptor PstS from Escherichia coli was cloned and sequenced from a lambda gt11 library of Mycobacterium tuberculosis by screening with monoclonal antibody 2A1-2. Its degree of similarity to the E. coli PstS is comparable to those of the previously described M. tuberculosis phosphate binding protein pab (Ag78, Ag5, or 38-kDa protein) and another M. tuberculosis protein which we identified recently. We suggest that the three M. tuberculosis proteins share a similar function and could be named PstS-1, PstS-2, and PstS-3, respectively. Molecular modeling of their three-dimensional structures using the structure of the E. coli PstS as a template and their inducibility by phosphate starvation support this view. Recombinant PstS-2 and PstS-3 were produced and purified by affinity chromatography. With PstS-1, these proteins were used to demonstrate the specificity of three groups of monoclonal antibodies. Using these antibodies in flow cytometry and immunoblotting analyses, we demonstrate that the three genes are expressed and their protein products are present and accessible at the mycobacterial surface as well as in its culture filtrate. Together with the M. tuberculosis genes encoding homologs of the PstA, PstB, and PstC components we cloned before, the present data suggest that at least one, and possibly several, related and functional ABC phosphate transporters exist in mycobacteria. It is hypothesized that the mycobacterial gene duplications presented here may be a subtle adaptation of intracellular pathogens to phosphate starvation in their alternating growth environments.
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PMID:Three different putative phosphate transport receptors are encoded by the Mycobacterium tuberculosis genome and are present at the surface of Mycobacterium bovis BCG. 913 6

The roles of multiple promoters in the synthesis of rRNA under different conditions of growth were investigated, using two mycobacterial species as model organisms. When Mycobacterium smegmatis was grown under optimal conditions, its two rRNA operons contributed equally, with two promoters, one from each operon, being responsible for most transcripts. In stationary-phase growth or balanced growth under carbon starvation conditions, one operon (rrnAf) dominated and its three promoters contributed more equally to the generation of transcripts. Mycobacterium tuberculosis has a single operon with two promoters, one of which generated 80% of transcripts, at all stages of growth. We infer that each promoter functions independently according to its intrinsic strength when cells are growing slowly so that one operon with three promoters is roughly equivalent to three operons with one promoter; at high growth rates, occlusion effects reduce the efficiency of multiple promoters to that of a single promoter.
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PMID:Roles of multiple promoters in transcription of ribosomal DNA: effects of growth conditions on precursor rRNA synthesis in mycobacteria. 979 Nov 29

Mycobacterium tuberculosis can persist for many years within host lung tissue without causing clinical disease. Little is known about the state in which the bacilli survive, although it is frequently referred to as dormancy. Some evidence suggests that cells survive in nutrient-deprived stationary phase. Therefore, we are studying stationary-phase survival of Mycobacterium smegmatis as a model for mycobacterial persistence. M. smegmatis cultures could survive 650 days of either carbon, nitrogen, or phosphorus starvation. In carbon-limited medium, cells entered stationary phase before the carbon source (glycerol) had been completely depleted and glycerol uptake from the medium continued during the early stages of stationary phase. These results suggest that the cells are able to sense when the glycerol is approaching limiting concentrations and initiate a shutdown into stationary phase, which involves the uptake of the remaining glycerol from the medium. During early stationary phase, cells underwent reductive cell division and became more resistant to osmotic and acid stress and pool mRNA stabilized. Stationary-phase cells were also more resistant to oxidative stress, but this resistance was induced during late exponential phase in a cell-density-dependent manner. Upon recovery in fresh medium, stationary-phase cultures showed an immediate increase in protein synthesis irrespective of culture age. Colony morphology variants accumulated in stationary-phase cultures. A flat colony variant was seen in 75% of all long-term-stationary-phase cultures and frequently took over the whole population. Cryo scanning electron microscopy showed that the colony organization was different in flat colony strains, flat colonies appearing less well organized than wild-type colonies. Competition experiments with an exponential-phase-adapted wild-type strain showed that the flat strain had a competitive advantage in stationary phase, as well a providing evidence that growth and cell division occur in stationary-phase cultures of M. smegmatis. These results argue against stationary-phase M. smegmatis cultures entering a quiescent state akin to dormancy but support the idea that they are a dynamic population of cells.
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PMID:Adaptation of Mycobacterium smegmatis to stationary phase. 986 40

Oxygen starvation triggers an adaptive stationary-phase response in Mycobacterium smegmatis. During this anaerobic stationary phase, RNA synthesis continues at a low but significant level. Employing a modified expressed-sequence-tag (EST) approach, in combination with the M. tuberculosis genome data and comparative Northern analysis, we have identified the first genes that show an increase in transcription in M. smegmatis cells that have entered anaerobic stationary phase. One gene encodes the counterpart of the M. tuberculosis NifS-like protein Rv1464. Two genes are homologues of M. tuberculosis Rv1460 and Rv3368c, of unknown function. Strikingly, several genes induced by oxygen starvation encode putative stress protection proteins (counterparts of M. tuberculosis DnaK, Rv0350; betaine-aldehyde dehydrogenase, Rv0768; thioredoxin reductase, Rv3913) and ABC transporters (counterparts of M. tuberculosis Rv1463, Rv1473, Rv3197). We conclude that development of general stress resistance and certain active transport processes might play a role in the survival of oxygen-starved M. smegmatis.
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PMID:Upregulation of stress response genes and ABC transporters in anaerobic stationary-phase Mycobacterium smegmatis. 1062 50


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