02447nas a2200241   4500008004100000022001400041245008500055210006900140260008900209300001000298490000700308520157200315653002001887653002501907653003101932653002801963653002501991100001702016700001902033700002102052700001902073856011302092       2008                        eng d  a0882-401000aPresence of a functional nitrate assimilation pathway in mycobacterium smegmatis0 aPresence of a functional nitrate assimilation pathway in mycobac  a24-28 OVAL RD, LONDON NW1 7DX, ENGLANDbACADEMIC PRESS LTD ELSEVIER SCIENCE LTDcJAN  a71-770 v443 a<p>Ability of Mycobacterium smegmatis to assimilate nitrate was evaluated in its active and dormant phase. Nitrate (10 mM), nitrite (0.5 mM) and ammonia (10 mM)allowed growth of M. smegmatis concomitant with their complete depletion from the culture in 144, 120 and 96 h, respectively, when used as sole nitrogen Source. Azide (50 mu M) stopped the growth of M. smegmatis when nitrate was used as sole nitrogen source. L-methionine-S-sulfoximine (L-MSO), which is a well-known inhibitor of glutamine synthetase, an enzyme also involved in nitrogen metabolic pathway, when applied at 10 mu g/ml concentration, completely inhibited the growth of the organism when nitrate or nitrite was used as sole nitrogen source. There was no effect of either azide or L-MSO at above concentrations on the growth of the organism when asparagine or ammonia was used as sole nitrogen source. More significantly, utilization of nitrate, nitrite and ammonia continued even in oxygen depletion induced dormant culture at the rates of 289, 25 and 354 mu M/day, respectively. These rates were 5-8 times slower than the rates of 1966, 127 and 2890 mu M/day, respectively, in active replicating phase. In the presence of azide (50 mu M) and L-MSO (10 mu g/ml), 2.1 and 1.51 logs reduction in viability of dormant M. smegmatis was observed using nitrate and nitrite, respectively, as sole nitrogen source. Altogether, the results indicated the presence of nitrate assimilation pathway operating in both active and dormant stage of M. smegmatis. (C) 2007 Elsevier Ltd. All rights reserved.</p>10aDormant bacilli10aGlutamine synthetase10aL-methionine-S-sulfoximine10aMycobacterium smegmatis10aNitrate assimilation1 aKhan, Arshad1 aAkhtar, Shamim1 aAhmad, Jawid, N.1 aSarkar, Dhiman  uhttp://library.ncl.res.in/content/presence-functional-nitrate-assimilation-pathway-mycobacterium-smegmatis-002130nas a2200229   4500008004100000022001400041245011900055210006900174260000800243300001100251490000700262520136100269653003001630653000801660653002501668653001101693653001701704100001701721700001901738700001901757856012401776       2022                        eng d  a2590-098600aProbes and techniques used in active and the hypoxia-based dormant state of an antitubercular drug screening assay0 aProbes and techniques used in active and the hypoxiabased dorman  cMAR  a1001150 v133 aCurrent antitubercular drug therapy requires more than six months and is unable to kill latent or dormant forms of tuberculosis. Thus, it is a need of new drug therapy to fight against dormant tuberculosis. However, the major obstacle in the development of novel drugs for dormant tuberculosis is the lack of relevant screening systems and using reliable probes to measure growth inhibition. Until now, several probes used in active state assays are significantly determining the inhibitory effect against the active state of mycobacteria. The dormant condition assays are based on hypoxia-derived dormancy which include resazurin reduction assay, nitrite reductase assay, XTT reduction menadione assay and low oxygen recovery assay. Major probes used in those assays are colorimetric/fluorescent dyes, enzymatic activity, and reporter genes include luciferase and fluorescent proteins. Although these dormant assays are based on hypoxia-induced features and difficult to maintain for a longer duration. Also, they further complicated by growth detection and pursuit of high throughput screening criteria. Here we reviewed complications of probes and assay techniques used for anti-dormant drug screening programs of tuberculosis. This will provide the knowledge to design better alternative drug screening method for the anti-dormant form of tuberculosis.10aActive and dormant states10aand10aDrug screening assay10aProbes10atuberculosis1 aYeware, Amar1 aAkhtar, Shamim1 aSarkar, Dhiman  uhttp://library.ncl.res.in/content/probes-and-techniques-used-active-and-hypoxia-based-dormant-state-antitubercular-drug