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Query: UMLS:C0026918 (Mycobacterium)
 52,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this study we analyzed microbiology results of tuberculosis in urinary system, in the area of Tuzla canton in period since 1993 to 2005 year. For microbiological diagnosis we tested samples of whole morning urine by method of concentration and homogenization by Petroff and inoculated on Loewenstein culture media. All grown culture was identified biochemical by production of niacin, reduction of nitrate and production of heat labile catalase. In this investigated period we tested 121,945 samples of different biological materials on Mycobacterium tuberculosis: sputum 89,433, gastrolavate 5,122, broncholavate 1,337, pleural exudation 1,356, punctuates 1,711, liquors 179, stools 149, blood 4, urine 22,654 samples. All urine samples were taken from 4,192 patients. Positive culture is found in 358 urine samples or in 1, 58%, or 173 patients or 4, 13%. From total 4,759 microbiologically diagnosed patients with all different types of tuberculosis in this period of time, with pulmonary tuberculosis there was 4,495 or 94, 45% patients and 264 or 5, 55% with extrapulmonal types of tuberculosis. Tuberculosis of urinary system is microbiologically diagnosed in 173 or 3, 63% patients out of total number of diagnosed tuberculosis cases. Tuberculosis of urinary system is diagnosed in 115 women and 58 men. In both sexes it was most often diagnosed in age of 65 to 74 year and in women in age of 45 to 54 year and in man in age 25 to 34 year. Tuberculosis of urinary system is more common in patients from Tuzla then from other town in Tuzla canton. It is also more common in patients that were treated in Clinic then those who were treated ambulatory. We can conclude that distance of place of living from place of microbiology laboratory significantly influence on microbiologically diagnostic of tuberculosis of urinary system.
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PMID:[Frequency of microbiologicaly diagnosed urinary system tuberculosis in Tuzla canton area]. 1817 86

The mycobacterial cell envelope consists of a characteristic cell wall skeleton (CWS), a mycoloyl arabinogalactan peptidoglycan complex, and related hydrophobic components that contribute to the cell surface properties. Since mycolic acids have recently been reported to play crucial roles in host immune response, detailed molecular characterization of mycolic acid subclasses and sub-subclasses of CWS from Mycobacterium bovis BCG Tokyo 172 (SMP-105) was performed. Mycolic acids were liberated by alkali hydrolysis from SMP-105, and their methyl esters were separated by silica gel TLC into three subclasses: alpha-, methoxy-, and keto-mycolates. Each mycolate subclass was further separated by silver nitrate (AgNO(3))-coated silica gel TLC into sub-subclasses. Molecular weights of individual mycolic acid were determined by MALDI-TOF mass spectrometry. alpha-Mycolates were sub-grouped into cis, cis-dicyclopropanoic (alpha1), and cis-monocyclopropanoic-cis-monoenoic (alpha2) series; methoxy-mycolates were sub-grouped into cis-monocyclopropanoic (m1), trans-monocyclopropanoic (m2), trans-monoenoic (m3), cis-monocyclopropanoic-trans-monoenoic (m4), cis-monoenoic (m5), and cis-monocyclopropanoic-cis-monoenoic (m6) series; and keto-mycolates were sub-grouped into cis-monocyclopropanoic (k1), trans-monocyclopropanoic (k2), trans-monoenoic (k3), cis-monoenoic (k4), and cis-monocyclopropanoic-cis-monoenoic (k5) series. The position of each functional group, including cyclopropane rings and methoxy and keto groups, was determined by analysis of the meromycolates with fast atom bombardment (FAB) mass spectrometry and FAB mass-mass spectrometry, and the cis/trans ratio of cyclopropane rings and double bonds were determined by NMR analysis of methyl mycolates. Mycolic acid subclass and molecular species composition of SMP-105 showed characteristic features including newly-identified cis-monocyclopropanoic-trans-monoenoic mycolic acid (m4).
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PMID:Comprehensive analysis of mycolic acid subclass and molecular species composition of Mycobacterium bovis BCG Tokyo 172 cell wall skeleton (SMP-105). 1817 79

The capability of Mycobacterium tuberculosis to rest in latency in the infected organism appears to be related to the disposal of detoxification mechanisms, which converts the nitric oxide (NO) produced by macrophages during the initial growth infection stage into a nitrate anion. Such a reaction appears to be associated with the truncated hemoglobin N (trHbN). Even though previous experimental and theoretical studies have examined the pathways used by NO and O2 to access the heme cavity, the eggression pathway of the nitrate anion is still a challenging question. In this work we present results obtained by means of classical and quantum chemistry simulations that show that trHbN is able to release rapidly the nitrate anion using an eggression pathway other than those used for the entry of both O2 and NO and that its release is promoted by hydration of the heme cavity. These results provide a detailed understanding of the molecular basis of the NO detoxification mechanism used by trHbN to guarantee an efficient NO detoxification and thus warrant survival of the microorganism under stress conditions.
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PMID:Mechanism of product release in NO detoxification from Mycobacterium tuberculosis truncated hemoglobin N. 1818 94

Growth and virulence of mycobacteria requires sulfur uptake. The Mycobacterium tuberculosis genome contains, in addition to the ABC sulfate permease cysTWA, three SLC26-related SulP genes of unknown function. We report that induction of Rv1739c expression in E. coli increased bacterial uptake of sulfate, but not Cl(-), formate, or oxalate. Uptake was time-dependent, maximal at pH 6.0, and exhibited a K(1/2) for sulfate of 4.0 muM. Na(+)-independent sulfate uptake was not reduced by bicarbonate, nitrate, or phosphate, but was inhibited by sulfite, selenate, thiosulfate, N-ethylmaleimide and carbonyl cyanide 3-chloro-phenylhydrazone. Sulfate uptake was also increased by overexpression of the Rv1739c transmembrane domain, but not of the cytoplasmic C-terminal STAS domain. Mutation to serine of the three cysteine residues of Rv1739c did not affect magnitude, pH-dependence, or pharmacology of sulfate uptake. Expression of Rv1739c in a M. bovis BCG strain lacking the ABC sulfate permease subunit CysA could not complement sulfate auxotrophy. Moreover, inducible expression of Rv1739c in an E. coli strain lacking CysA did not increase sulfate uptake by intact cells. Our data show that facilitation of bacterial sulfate uptake by Rv1739c requires CysA and its associated sulfate permease activity, and suggest that Rv1739c may be a CysTWA-dependent sulfate transporter.
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PMID:Increased sulfate uptake by E. coli overexpressing the SLC26-related SulP protein Rv1739c from Mycobacterium tuberculosis. 1825 26

When oxygen is slowly depleted from growing cultures of Mycobacterium tuberculosis, they enter a state of nonreplicating persistence that resembles the dormant state seen with latent tuberculosis. In this hypoxic state, nitrate reductase activity is strongly induced. Nitrate in the medium had no effect on long-term persistence during gradual oxygen depletion (Wayne model) for up to 46 days, but significantly enhanced survival during sudden anaerobiosis. This enhancement required a functional nitrate reductase. Thioridazine is a member of the class of phenothiazines that act, in part, by inhibiting respiration. Thioridazine was toxic to both actively growing and nonreplicating cultures of M. tuberculosis. At a sublethal concentration of thioridazine, nitrate in the medium improved the growth. At lethal concentrations of thioridazine, nitrate increased survival during aerobic incubation as well as in microaerobic cultures that had just entered nonreplicating persistence (NRP-1). In contrast, the survival of anaerobic persistent (NRP-2) cultures exposed to thioridazine was not increased by the addition of nitrate. Nitrate reduction is proposed to play a role during the sudden interruption of aerobic respiration due to causes such as hypoxia, thioridazine, or nitric oxide.
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PMID:Nitrate enhances the survival of Mycobacterium tuberculosis during inhibition of respiration. 1829 25

Mycobacterium tuberculosis is the causative agent of tuberculosis, a disease that affects one-third of the world's population. The sole extant vaccine for tuberculosis is the live attenuated Mycobacterium bovis bacillus Calmette-Guerin (BCG). We examined 13 representative BCG strains from around the world to ascertain their ability to express DosR-regulated dormancy antigens. These are known to be recognized by T cells of M. tuberculosis-infected individuals, especially those harboring latent infections. Differences in the expression of these antigens could be valuable for use as diagnostic markers to distinguish BCG vaccination from latent tuberculosis. We determined that all BCG strains were defective for the induction of two dormancy genes: narK2 (Rv1737c) and narX (Rv1736c). NarK2 is known to be necessary for nitrate respiration during anaerobic dormancy. Analysis of the narK2/X promoter region revealed a base substitution mutation in all tested BCG strains and M. bovis in comparison to the M. tuberculosis sequence. We also show that nitrate reduction by BCG strains during dormancy was greatly reduced compared to M. tuberculosis and varied between tested strains. Several dormancy regulon transcriptional differences were also identified among the strains, as well as variation in their growth and survival. These findings demonstrate defects in DosR regulon expression during dormancy and phenotypic variation between commonly used BCG vaccine strains.
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PMID:Mycobacterium bovis BCG vaccine strains lack narK2 and narX induction and exhibit altered phenotypes during dormancy. 1836 35

The 2-ethyhexyl nitrate (2-EHN) is currently added to diesel oil to improve ignition and boost cetane number. The biodegradability of this widely used chemical needed to be assessed in order to evaluate the environmental impact in case of accidental release. In aerobic liquid cultures, biodegradation of 2-EHN was assessed in biphasic liquid cultures using an inert non-aqueous phase liquid such as 2,2,4,4,6,8,8-heptamethylnonane (HMN) as solvent for the hydrophobic substrate. 2-EHN was found to be biodegradable by microbial communities from refinery wastewater treatment plants, but was recalcitrant to those of urban wastewater treatment facilities. Out of eighteen hydrocarbon-polluted or non-polluted soil samples, six microbial populations were also able to degrade 2-EHN. However, strain isolation from these microbial populations was rather difficult suggesting close cooperation between members of the microbial communities. Specific axenic bacterial strains selected for their ability to catabolize recalcitrant-hydrocarbons were also tested for their capacity to degrade 2-EHN. In liquid cultures with HMN phase as non-aqueous phase liquid, some Mycobacterium austroafricanum strains were found to degrade and mineralize 2-EHN significantly.
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PMID:Biodegradability of 2-ethylhexyl nitrate (2-EHN), a cetane improver of diesel oil. 1856 32

The survival of Mycobacterium tuberculosis requires detoxification of host *NO. Oxygenated Mycobacterium tuberculosis truncated hemoglobin N catalyzes the rapid oxidation of nitric oxide to innocuous nitrate with a second-order rate constant (k'(NOD) approximately 745 x 10(6) m(-1) x s(-1)), which is approximately 15-fold faster than the reaction of horse heart myoglobin. We ask what aspects of structure and/or dynamics give rise to this enhanced reactivity. A first step is to expose what controls ligand/substrate binding to the heme. We present evidence that the main barrier to ligand binding to deoxy-truncated hemoglobin N (deoxy-trHbN) is the displacement of a distal cavity water molecule, which is mainly stabilized by residue Tyr(B10) but not coordinated to the heme iron. As observed in the Tyr(B10)/Gln(E11) apolar mutants, once this kinetic barrier is lowered, CO and O(2) binding is very rapid with rates approaching 1-2 x 10(9) m(-1) x s(-1). These large values almost certainly represent the upper limit for ligand binding to a heme protein and also indicate that the iron atom in trHbN is highly reactive. Kinetic measurements on the photoproduct of the *NO derivative of met-trHbN, where both the *NO and water can be directly followed, revealed that water rebinding is quite fast (approximately 1.49 x 10(8) s(-1)) and is responsible for the low geminate yield in trHbN. Molecular dynamics simulations, performed with trHbN and its distal mutants, indicated that in the absence of a distal water molecule, ligand access to the heme iron is not hindered. They also showed that a water molecule is stabilized next to the heme iron through hydrogen-bonding with Tyr(B10) and Gln(E11).
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PMID:Ligand binding to truncated hemoglobin N from Mycobacterium tuberculosis is strongly modulated by the interplay between the distal heme pocket residues and internal water. 1867 95

2-Ethyhexyl nitrate (2-EHN) is a major additive of fuel that is used to increase the cetane number of diesel. Because of its wide use and possible accidental release, 2-EHN is a potential pollutant of the environment. In this study, Mycobacterium austroafricanum IFP 2173 was selected from among several strains as the best 2-EHN degrader. The 2-EHN biodegradation rate was increased in biphasic cultures where the hydrocarbon was dissolved in an inert non-aqueous-phase liquid, suggesting that the transfer of the hydrophobic substrate to the cells was a growth-limiting factor. Carbon balance calculation, as well as organic-carbon measurement, indicated a release of metabolites in the culture medium. Further analysis by gas chromatography revealed that a single metabolite accumulated during growth. This metabolite had a molecular mass of 114 Da as determined by gas chromatography/mass spectrometry and was provisionally identified as 4-ethyldihydrofuran-2(3H)-one by liquid chromatography-tandem mass spectrometry analysis. Identification was confirmed by analysis of the chemically synthesized lactone. Based on these results, a plausible catabolic pathway is proposed whereby 2-EHN is converted to 4-ethyldihydrofuran-2(3H)-one, which cannot be metabolized further by strain IFP 2173. This putative pathway provides an explanation for the low energetic efficiency of 2-EHN degradation and its poor biodegradability.
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PMID:Biodegradation of 2-ethylhexyl nitrate by Mycobacterium austroafricanum IFP 2173. 1872 59

Knowledge about nitrogen metabolism and control in the genus Mycobacterium is sparse, especially compared to the state of knowledge in related actinomycetes like Streptomyces coelicolor or the close relative Corynebacterium glutamicum. Therefore, we screened the published genome sequences of Mycobacterium smegmatis, Mycobacterium tuberculosis, Mycobacterium bovis, Mycobacterium avium ssp. paratuberculosis and Mycobacterium leprae for genes encoding proteins for uptake of nitrogen sources, nitrogen assimilation and nitrogen control systems, resulting in a detailed comparative genomic analysis of nitrogen metabolism-related genes for all completely sequenced members of the genus. Transporters for ammonium, nitrate, and urea could be identified, as well as enzymes crucial for assimilation of these nitrogen sources, i.e. glutamine synthetase, glutamate dehydrogenase, glutamate synthase, nitrate reductase, nitrite reductase, and urease proteins. A reduction of genes encoding proteins for nitrogen transport and metabolism was observed for the pathogenic mycobacteria, especially for M. leprae. Signal transduction components identified for the different species include adenylyl- and uridylyltransferase and a P(II)-type signal transduction protein. Exclusively for M. smegmatis, two homologs of putative nitrogen regulatory proteins were found, namely GlnR and AmtR, while in other mycobacteria, AmtR was absent and GlnR seems to be the nitrogen transcription regulator protein.
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PMID:A genomic view on nitrogen metabolism and nitrogen control in mycobacteria. 1882 37


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