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)

During the period 1973 to 1976 inclusive, 1206 badger carcases were examined for evidence of tuberculosis and other diseases. Tuberculosis was the major cause of natural death, killing 39 per cent of the natural death cases, followed by bite wounding and starvation. Road traffic accidents were the greatest single cause of death.
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PMID:Cause of ill health and natural death in badgers in Gloucestershire. 39 69

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

The effects of aging and malnutrition on BAL cells, such as metabolic disorders and various immune responses, have been examined. In malnourished animals, the composition of phospholipids in BAL cells were changed, and the decrease in the number of specific prednisolone binding sites was recognized. Furthermore, the decrease of total cell counts and the population of lymphocytes, neutrophils and Ia-positive macrophages were observed in BAL cells. However, BAL cells obtained from heat-killed BCG sensitized animals in malnutrition preserved a good responsiveness. These impaired cellular development following starvation could be partly reversed by some antigenic factors, resulting in heavier cell infiltration and granuloma formation in the lung tissues. These observations suggest that alterations in immune responses accompanying malnutrition may be closely related to the mechanism of reactivation and the clinical course and profile of tuberculosis.
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PMID:[Activation and metabolic changes of macrophages in immunology of tuberculosis]. 281 Oct 6

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

Tuberculous infection was first introduced to the majority of the Inuit (Eskimos) in the first half of this century. In the 1950s tuberculosis became a grave problem with the mortality rate approaching 1% per annum and the incident rate almost 3%. The annual risk of infection has been estimated at 25% per annum. These are probably the highest rates recorded anywhere in the world in the 20th century. Some 20-30 years ago, an intensive case-finding programme as well as a treatment programme began in all three jurisdictions where the Inuit live (northern Canada, Alaska and Greenland). The preventive measures differed; Alaska relying mainly on chemoprophylaxis and Greenland on BCG vaccination, while Canada adopted both measures. Over the last 20 years, the rates fell rapidly with the mortality rate approaching zero, and the morbidity (incidence) rate falling (Canadian Inuit) by the record 14% per annum. The high rates in the Inuit were, in part, an expression of the lack of 'natural' resistance acquired by other races through the exposure to tubercle bacilli for many generations. Over-crowding in igloos and frequent starvation among those Inuit who relied on cariboo meat, undoubtedly contributed a great deal to the gravity of the problem. The rapid decline of the rates is without doubt primarily caused by the intensive tuberculosis programme and the compliance of the Inuit with the demands of this programme; better housing and in some cases, improved nutrition doubtlessly also played a part.
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PMID:Tuberculosis in Inuit. 633 10

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

Inorganic polyphosphate (poly P) is a chain of tens or many hundreds of phosphate (Pi) residues linked by high-energy phosphoanhydride bonds. Despite inorganic polyphosphate's ubiquity--found in every cell in nature and likely conserved from prebiotic times--this polymer has been given scant attention. Among the reasons for this neglect of poly P have been the lack of sensitive, definitive, and facile analytical methods to assess its concentration in biological sources and the consequent lack of demonstrably important physiological functions. This review focuses on recent advances made possible by the introduction of novel, enzymatically based assays. The isolation and ready availability of Escherichia coli polyphosphate kinase (PPK) that can convert poly P and ADP to ATP and of a yeast exopolyphosphatase that can hydrolyze poly P to Pi, provide highly specific, sensitive, and facile assays adaptable to a high-throughput format. Beyond the reagents afforded by the use of these enzymes, their genes, when identified, mutated, and overexpressed, have offered insights into the physiological functions of poly P. Most notably, studies in E. coli reveal large accumulations of poly P in cellular responses to deficiencies in an amino acid, Pi, or nitrogen or to the stresses of a nutrient downshift or high salt. The ppk mutant, lacking PPK and thus severely deficient in poly P, also fails to express RpoS (a sigma factor for RNA polymerase), the regulatory protein that governs > or = 50 genes responsible for stationary-phase adaptations to resist starvation, heat and oxidant stresses, UV irradiation, etc. Most dramatically, ppk mutants die after only a few days in stationary phase. The high degree of homology of the PPK sequence in many bacteria, including some of the major pathogenic species (e.g. Mycobacterium tuberculosis, Neisseria meningitidis, Helicobacter pylori, Vibrio cholerae, Salmonella typhimurium, Shigella flexneri, Pseudomonas aeruginosa, Bordetella pertussis, and Yersinia pestis), has prompted the knockout of their ppk gene to determine the dependence of virulence on poly P and the potential of PPK as a target for antimicrobial drugs. In yeast and mammalian cells, exo- and endopolyphosphatases have been identified and isolated, but little is known about the synthesis of poly P or its physiologic functions. Whether microbe or human, all species depend on adaptations in the stationary phase, which is truly a dynamic phase of life. Most research is focused on the early and reproductive phases of organisms, which are rather brief intervals of rapid growth. More attention needs to be given to the extensive period of maturity. Survival of microbial species depends on being able to manage in the stationary phase. In view of the universality and complexity of basic biochemical mechanisms, it would be surprising if some of the variety of poly P functions observed in microorganisms did not apply to aspects of human growth and development, to aging, and to the aberrations of disease. Of theoretical interest regarding poly P is its antiquity in prebiotic evolution, which along with its high energy and phosphate content, make it a plausible precursor to RNA, DNA, and proteins. Practical interest in poly P includes many industrial applications, among which is the microbial removal of Pi in aquatic environments.
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PMID:Inorganic polyphosphate: a molecule of many functions. 1087 45


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