Browsing by Author "Singh, V."
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Item Antimicrobial and repellent activity of the essential oils of two lamiaceae cultivated in Western Himalaya(Bentham Science Publishers B.V., 2015) Stappen, Iris; Ali, Abbas; Tabanca, Nurhayat; Khan,Ikhlas A.; Wanner, J�rgen; Gochev, Velizar K.; Singh, Virendra; Lal, Brij; Jaitak, Vikas; Kaul, Vijay K.; Schmidt, Erich; Jirovetz, Leopold; Stappen, I.; Ali, A.; Tabanca, N.; Khan, I.A.; Wanner, J.; Gochev, V.K.; Singh, V.; Lal, B.; Jaitak, V.; Kaulh, V.K.; Schmidt, E.; Jirovetz, L.The essential oils of two Lamiaceae cultivated in Western Himalaya were examined on their antimicrobial, biting deterrent as well as larvicidal activity. Additionally their odors are described and their chemical compositions analyzed by GC-MS are given. The main component of Nepeta cataria oil was 4a?,7?,7a?-nepetalactone (85%), whereas camphor (27%) and 1,8-cineol (27%) were dominant in the oil of Rosmarinus officinalis. The studied essential oils demonstrated high to moderately antimicrobial activity against reference strains, clinical and food spoilage isolates of Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella abony and Candida albicans (MIC 160-640 ?g/ml) and indicated low activity against Pseudomonas aeruginosa and P. fluorescens. Both oils showed biting deterrent activity above solvent control but lower than DEET. Nepeta catarica essential oil exhibited high toxicity with LD50 value of 20.2 whereas R. officinalis oil showed only 50% mortality at the highest tested dose of 125 ppm against 1-day old Aedes aegypti larvae at 24-hour post treatment. ? 2015 Bentham Science Publishers.Item Heterologous expression, purification and characterization of L-type lectin homologue from Leishmania donovani(Elsevier, 2015) Singh, V.; Nair, D.N.; Kaushal, R.S.; Kumar, M.; Pappachan, A.; Singh, D.D.Leishmaniasis, a disease of the developing world affects about 12 million people and has limited therapeutic interventions available. L-type lectins, Endoplasmic Reticulum Golgi Intermediate Compartment/Vesicular Integral Proteins (ERGIC-53/VIP36) are involved in protein sorting in luminal compartments of animal cells and are important for parasite biology. A lectin homologue was identified through a bioinformatics analysis of Leishmania genome and it was found to have N-terminal conserved carbohydrate recognition domain (CRD) and a unique C-terminal region rich in repetitive amino acids and a poly glutamine tract. The N-terminal CRD region was cloned and expressed in Escherichia coli, but gave an insoluble expression which was re-solubilized by on column refolding. The fold integrity was checked through CD, fluorescence and functional assay of hemagglutination activity using rabbit erythrocyte. Bioinformatics analysis identified 15 members from Tritryps (Leishmania spp., Trypanosoma spp.) and they separate out as a distinct clade in the global phylogenetic analysis of all ERGIC-53/VIP36 sequences downloaded from Uniprot. Our analysis shows that the extended C-terminal regions with repeats is unique to Tritryps and this repeat pattern is different in sequences from Leishmania spp. and Trypanosoma spp. and all these features make this protein an interesting candidate for further detailed studies. ? 2015 The Author. Published by Elsevier B.V.Item Study of the shell effect on nuclear dissipation via neutron multiplicity measurement(2014) Singh, V.; Behera, B.R.; Sadhukhan, J.; Pal, S.Experimental neutron multiplicity data has been fitted using the Kramers' fission width, in statistical model calculations with and without inclusion of shell corrections in nuclear level density, nuclear masses and fission barrier. It has been found that the magnitude of dissipation strength changes to a large extent with inclusion of shell corrections in different ingredients of the statistical model. These observations clearly demonstrate the importance of shell corrections in statistical model calculations. ? Owned by the authors, published by EDP Sciences, 2014.