S. B. Pandey

Identification of 1-[4-Benzyloxyphenyl)-but-3-enyl]-1H-azoles as New Class of Antitubercular and Antimicrobial Agents

A series of 1-[(4-benzyloxyphenyl)-but-3-enyl]-1H-azoles has been identified as potent antitubercular agents against Mycobacterium tuberculosis. Synthesis of compounds involved acid catalyzed ring-opening of cyclopropyl ring of phenyl cyclopropyl methanols followed by nucleophilic attack of the azoles on the carbocation intermediates. Several of the compounds 26, 34, and 36 exhibited significant antitubercular activities with MIC value as low as 1.56, 1.56, and 0.61 μg/mL, respectively, comparable to many standard drugs. These compounds were also screened against other strains of bacteria and fungi, and few of them showed good antifungal activity against A. fumigatus, responsible for lung infection.

Intranight optical variability of \gamma-ray loud Narrow Line Seyfert 1 galaxies

The Large Area Telescope (LAT) onboard the {\it Fermi} Gamma Ray Space Telescope has detected \gamma-ray emission from some Narrow Line Seyfert 1(NLSy1) galaxies. This indicates the presence of relativistic jets in these sources similar to blazars and radio galaxies. In an attempt to have an idea of the intranight optical variability (INOV) characteristics of these \gamma-ray loud NLSy1 galaxies, we have carried out optical flux monitoring observations of three NLSy1 galaxies detected by {\it Fermi}/LAT: 1H 0323+342, PMN J0948+0022 and PKS 1502+036. These optical monitoring observations showed the presence of rapid optical flux variations in these sources. The intranight differential light curves of these sources have revealed flux variations on time scales of hours with amplitudes of variability > 3 percent for most of the time. On using the {\it F}-statistics to classify the variability nature of these sources, we obtained a duty cycle (DC) of INOV of ~85 percent. Alternatively, the more commonly used {\it C}-statistics gave a DC of INOV of ~57 percent. Such high DC of INOV are characteristics of the BL Lac class of AGN. The results of our monitoring observations thus indicate that there is similarity in the INOV nature of \gamma-ray loud NLSy1 galaxies and BL Lac objects, arguing strongly for the presence of relativistic jets aligned closely to the observers line of sight. Moreover, our dense monitoring observations on some of the nights have led to the clear detection of some mini-flares superimposed on the flux variations during the night over timescales as short as 12 minutes. The detection of short timescale flux variability in the sources studied here is clearly due to stronger time compression leading to the jets in these sources having large Doppler factors, similar to that of the inner jets of TeV blazars.

TIFR Near Infrared Imaging Camera-II on the 3.6 m Devasthal Optical Telescope

TIFR Near Infrared Imaging Camera-II is a closed-cycle Helium cryo-cooled imaging camera equipped with a Raytheon 512 x 512 pixels InSb Aladdin III Quadrant focal plane array having sensitivity to photons in the 1-5 microns wavelength band. In this paper, we present the performance of the camera on the newly installed 3.6-m Devasthal Optical Telescope (DOT) based on the calibration observations carried out during 2017 May 11-14 and 2017 October 7-31. After the preliminary characterization, the camera has been released to the Indian and Belgian astronomical community for science observations since 2017 May. The camera offers a field-of-view of ~86.5 arcsec x 86.5 arcsec on the DOT with a pixel scale of 0.169 arcsec. The seeing at the telescope site in the near-infrared bands is typically sub-arcsecond with the best seeing of ~0.45 arcsec realized in the near-infrared K-band on 2017 October 16. The camera is found to be capable of deep observations in the J, H and K bands comparable to other 4-m class telescopes available world-wide. Another highlight of this camera is the observational capability for sources up to Wide-field Infrared Survey Explorer (WISE) W1-band (3.4 microns) magnitudes of 9.2 in the narrow L-band (nbL; lambda_{cen} ~3.59 microns). Hence, the camera could be a good complementary instrument to observe the bright nbL-band sources that are saturated in the Spitzer-Infrared Array Camera ([3.6] <= 7.92 mag) and the WISE W1-band ([3.4] <= 8.1 mag). Sources with strong polycyclic aromatic hydrocarbon (PAH) emission at 3.3 microns are also detected. Details of the observations and estimated parameters are presented in this paper.

Response Surface Methodology-Genetic Algorithm Based Medium Optimization, Purification, and Characterization of Cholesterol Oxidase from Streptomyces rimosus

The applicability of the statistical tools coupled with artificial intelligence techniques was tested to optimize the critical medium components for the production of extracellular cholesterol oxidase (COD; an enzyme of commercial interest) from Streptomyces rimosus MTCC 10792. The initial medium component screening was performed using Placket-Burman design with yeast extract, dextrose, starch and ammonium carbonate as significant factors. Response surface methodology (RSM) was attempted to develop a statistical model with a significant coefficient of determination (R2 = 0.89847), followed by model optimization using Genetic Algorithm (GA). RSM-GA based optimization approach predicted that the combination of yeast extract, dextrose, starch and ammonium carbonate at concentrations 0.99, 0.8, 0.1, and 0.05 g/100 ml respectively, has resulted in 3.6 folds increase in COD production (5.41 U/ml) in comparison with the un-optimized medium (1.5 U/ml). COD was purified 10.34 folds having specific activity of 12.37 U/mg with molecular mass of 54 kDa. The enzyme was stable at pH 7.0 and 40 °C temperature. The apparent Michaelis constant (Km) and Vmax values of COD were 0.043 mM and 2.21 μmol/min/mg, respectively. This is the first communication reporting RSM-GA based medium optimization, purification and characterization of COD by S. rimosus isolated from the forest soil of eastern India.

Leishmania donovani molecules recognized by sera of filaria infected host facilitate filarial infection

We earlier found that F6 fraction of human filaria Brugia malayi cross-reacted with sera of Leishmania donovani infected hamsters and immunization with F6 inhibited both filarial and leishmanial infections. In the present study, we identified a 52.9–93.6 kDa fraction (Ld1) of L. donovani that cross-reacted with sera of B. malayi infected animals and investigated effect of Ld1 on filarial infection. Immunization of BALB/c mice with Ld1 facilitated B. malayi infection with remarkable increase in parasite burden. Facilitation of filarial infection was associated with downregulated cell proliferation, IL-5, IL-13, IFN-γ, TNF-α, and IL-2 levels and upregulated IL-4 and TGF-β. Ld1 exposure also suppressed MHC class-I, MHC class-II, and FcεR1 expression, and phagocytosis in naive mouse macrophages, and CD4+, CD8+, and CD19+ cell population in mouse spleen. Two-dimensional electrophoresis and matrix-assisted laser desorption ionization–time of flight-mass spectrometry revealed eight proteins in Ld1: putative heat shock protein (HSP) 70-related protein 1, HSP70 mitochondrial precursor, alanine aminotransferase, 2,3-bisphosphoglycerate-independent phosphoglycerate mutase, protein disulfide isomerase, putative ATPase beta subunit, trypanothione reductase, and a hypothetical protein. HSP70 protein mitochondrial precursor and trypanothione reductase showed homology with Trypanosoma cruzi and L. donovani, respectively, and the rest 6 proteins including hypothetical protein bear homology with L. infantum. In conclusion, the present study for the first time shows that immunization with filarial cross-reactive Ld1 fraction of L. donovani facilitates filarial infection by modulating Th1 and Th2 responses. Ld1 molecules may therefore facilitate filarial infection in filaria-leishmania co-infection.

SN 2015as: A low luminosity Type IIb supernova without an early light curve peak

We present results of the photometric (from 3 to 509 days past explosion) and spectroscopic (up to 230 days past explosion) monitoring campaign of the He-rich Type IIb supernova (SN) 2015as. The {\it (B-V)} colour evolution of SN 2015as closely resemble those of SN 2008ax, suggesting that SN 2015as belongs to the SN IIb subgroup that does not show the early, short-duration photometric peak. The light curve of SN 2015as reaches the

Past, Present, and Future of Antifungal Drug Development

B

Intranight optical variability of -ray-loud narrow-line Seyfert 1 galaxies

-band maximum about 22 days after the explosion, at an absolute magnitude of -16.82

GRB 071011, optical afterglow.

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GRB 060218: optical/nIR observations at La Palma.

0.18 mag. At