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

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 < 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.

10aMycobacterium smegmatis10anitrate reductase10aWayne model1 aKhan, Arshad1 aSarkar, Dhiman uhttps://library.ncl.res.in/content/identification-respiratory-type-nitrate-reductase-and-its-role-survival-mycobacterium-002448nas a2200241 4500008004100000022001400041245008500055210006900140260008900209300001000298490000700308520157200315653002001887653002501907653003101932653002801963653002501991100001702016700001902033700002102052700001902073856011402092 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

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.

10aDormant bacilli10aGlutamine synthetase10aL-methionine-S-sulfoximine10aMycobacterium smegmatis10aNitrate assimilation1 aKhan, Arshad1 aAkhtar, Shamim1 aAhmad, Jawid, N.1 aSarkar, Dhiman uhttps://library.ncl.res.in/content/presence-functional-nitrate-assimilation-pathway-mycobacterium-smegmatis-001971nas a2200217 4500008004100000022001400041245010800055210006900163260008000232300002400312490000600336520115500342653001301497653002801510653001501538653001701553653001401570100002101584700001901605856012901624 2015 eng d a1664-302X00aQualitative and quantitative proteomic analysis of vitamin C induced changes in mycobacterium smegmatis0 aQualitative and quantitative proteomic analysis of vitamin C ind aPO BOX 110, LAUSANNE, 1015, SWITZERLANDbFRONTIERS RESEARCH FOUNDATIONcMAY aArticle Number: 4510 v63 a

Vitamin C is a critical dietary nutrient in human which has a wide range of regulatory effects on gene expression and physiology of Mycobacterium tuberculosis that leads to a dormant drug-tolerant phenotype. In the presence of iron, vitamin C shows a high bactericidal activity even in the drug resistant phenotype of M. tuberculosis. The regulatory mechanisms underlying vitamin C induced adaptations are largely unknown due to lack of functional genomics data in this field. In this study, we attempt to characterize the direct effect of vitamin C treatment on the physiology of actively growing Mycobacterium smegmatis. The study chose M. smegmatis as it is a fast-growing bacterium and a non-pathogenic model system which shares many physiological features with the pathogenic M. tuberculosis including dormancy and its regulation. The proteomic adaptation of M. smegmatis on vitamin C treatment demonstrates the important changes in cellular and metabolic process such as reversal of tricarboxylic acid cycle, decrease in ATP synthesis, decrease in iron acquisition and storage, and induction of dormancy regulators WhiB3, PhoP, and Lsr2.

10adormancy10aMycobacterium smegmatis10aproteomics10atuberculosis10avitamin C1 aMishra, Abhishek1 aSarkar, Dhiman uhttps://library.ncl.res.in/content/qualitative-and-quantitative-proteomic-analysis-vitamin-c-induced-changes-mycobacterium-1