02567nas a2200193   4500008004100000022001400041245012700055210006900182260008900251300001000340490000700350520178700357653002802144653002202172653001602194100001702210700001902227856012702246       2006                        eng d  a0882-401000aIdentification of a respiratory-type nitrate reductase and its role for survival of mycobacterium smegmatis in wayne model0 aIdentification of a respiratorytype nitrate reductase and its ro  a24-28 OVAL RD, LONDON NW1 7DX, ENGLANDbACADEMIC PRESS LTD ELSEVIER SCIENCE LTDcAUG  a90-950 v413 a<p>Nitrate reductase (NR) is found to be expressed in certain mycobacterium sp. whose link with the development of persistence is yet to be resolved. The present study demonstrates the action of selective inhibitors on NR as well as in the survival of Mycobacterium smegmatis using Wayne's model. During gradual shift down to anaerobic stage in Wayne's model, conversion of nitrate to nitrite became apparent in M. smegmatis. More than 97 percent inhibition was observed for the conversion of nitrate to nitrite by azide (0.05 mM) and thiocyanate (20 mM) in both whole-cell as well as its cell-free lysate, respectively. Under identical condition, chlorate (20 mM) inhibited nitrate reduction by 67 and 10 percent, respectively. At these concentrations, neither of azide, thiocyanate nor chlorate had any significant effect on cell growth under aerobic condition. In Wayne's culture model, thiocyanate and chlorate inhibited the growth of M. smegmatis by almost 2 logs at the same concentrations whereas azide inhibited by almost 1.75 log when added at the time of inoculation. Exposure of same culture at 96 h after inoculation in Wayne's model to these inhibitors showed 1.74, 1.95 and 2.37 log inhibition of viable cells with respect to azide, thiocyanate and chlorate. These findings further indicated that NR inhibitors kill the bacilli at anaerobic stage under the experimental condition mentioned. Metronidazole (MTZ) (2 mM) and Nitrofurantoin (NIT) (0.3 mM) reduced the cell number at both stages by &lt; 0.7log. They did not have any effect on NR. Altogether, the results clearly indicate that NR-specific inhibitors could become more promising in killing the bacilli at anaerobic stage than the available conventional drugs. (c) 2006 Elsevier Ltd. All rights reserved.</p>10aMycobacterium smegmatis10anitrate reductase10aWayne model1 aKhan, Arshad1 aSarkar, Dhiman  uhttps://library.ncl.res.in/content/identification-respiratory-type-nitrate-reductase-and-its-role-survival-mycobacterium-002223nas a2200217   4500008004100000022001400041245016600055210006900221260007600290300001200366490000700378520134900385653003001734653001401764653003101778653002201809653000901831100001801840700001901858856012801877       2012                        eng d  a1087-057100aPotential use of nitrate reductase as a biomarker for the identification of active and dormant inhibitors of mycobacterium tuberculosis in a THP1 infection model0 aPotential use of nitrate reductase as a biomarker for the identi  a2455 TELLER RD, THOUSAND OAKS, CA 91320 USAbSAGE PUBLICATIONS INCcAUG  a966-9730 v173 a<p>The development of a macrophage-based, antitubercular high-throughput screening system could expedite discovery programs for identifying novel inhibitors. In this study, the kinetics of nitrate reduction (NR) by Mycobacterium tuberculosis during growth in Thp1 macrophages was found to be almost parallel to viable bacilli count. NR in the culture medium containing 50 mM of nitrate was found to be optimum on the fifth day after infection with M. tuberculosis. The signal-to-noise (S/N) ratio and Z-factor obtained from this macrophage-based assay were 5.4 and 0.965, respectively, which confirms the robustness of the assay protocol. The protocol was further validated by using standard antitubercular inhibitors such as rifampicin, isoniazid, streptomycin, ethambutol, and pyrazinamide, added at their IC90 value, on the day of infection. These inhibitors were not able to kill the bacilli when added to the culture on the fifth day after infection. Interestingly, pentachlorophenol and rifampicin killed the bacilli immediately after addition on the fifth day of infection. Altogether, this assay protocol using M. tuberculosis-infected Thp-1 macrophages provides a novel, cost-efficient, robust, and easy-to-perform screening platform for the identification of both active and hypoxic stage-specific inhibitors against tuberculosis.</p>10ahigh-throughput screening10ainhibitor10aMycobacterium tuberculosis10anitrate reductase10aTHP11 aSarkar, Sampa1 aSarkar, Dhiman  uhttps://library.ncl.res.in/content/potential-use-nitrate-reductase-biomarker-identification-active-and-dormant-inhibitors-0