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Regioselective hydroxylation of isoflavones by Streptomyces avermitilis MA-4680
Roh, C.,Seo, S.H.,Choi, K.Y.,Cha, M.,Pandey, B.P.,Kim, J.H.,Park, J.S.,Kim, D.H.,Chang, I.S.,Kim, B.G. Society for Bioscience and Bioengineering, Japan ; 2009 Journal of bioscience and bioengineering Vol.108 No.1
Screening of bacterial whole cells was performed for regioselective hydroxylation of daidzein and genistein. Among the strains examined, Streptomyces avermitilis MA-4680 showed high ortho-dihydroxylation activity to produce 3',4',7-trihydroxyisoflavone and 3',4',5,7-tetrahydroxyisoflavone from daidzein (4',7-dihydroxyisoflavone) and genistein (4',5,7-trihydroxyisoflavone), respectively. Using 100 mg cells (wet wt.) and 1% (v/v) Triton X100 in 1 ml of total reaction volume, where 100 μl of the substrate solution (0.5 mM in 10% (v/v) mixed solvent of DMSO:MeOH=3:7) was added to 900 μl of potassium phosphate buffer (100 mM, pH 7.2), a 16% molar conversion yield of 3',4',7-trihydroxyisoflavone was obtained from 0.5 mM daidzein after 24 h of reaction time at 28 <SUP>o</SUP>C and 200 rpm. Ketoconazole significantly (ca. 90%) inhibited the ortho-hydroxylation activity of daidzein, suggesting that cytochrome P450 enzymes putatively play roles in regiospecific daidzein hydroxylation. The analysis of the reaction products was determined by gas chromatography/mass spectrometry (GC/MS) and <SUP>1</SUP>H NMR.
Shit, N.,Singh, R.P.,Sastry, K.V.H.,Agarwal, R.,Singh, R.,Pandey, N.K.,Mohan, J. Asian Australasian Association of Animal Productio 2012 Animal Bioscience Vol.25 No.7
Environmental stress boosts the levels of stress hormones and accelerates energy expenditure which subsequently imbalance the body's homeostasis. L-ascorbic acid (L-AA) has been recognized to mitigate the negative impact of environmental stress on production performances in birds. The present investigation was carried out to elucidate the effect of different dietary levels of L-AA on production performance, egg quality traits and fertility in Japanese quail at low ambient temperature. Sixty matured females (15 wks) were equally divided into three groups (20/group) based on the different dietary levels of L-AA (0, 250 and 500 ppm) and coupled with an equal number of males (1:1) obtained from the same hatch. They were managed in uniform husbandry conditions without restriction of feed and water at 14 h photo-schedule. Except for feed efficiency, body weight change, feed consumption and hen-day egg production were recorded highest in 500 ppm L-AA supplemented groups. Among the all egg quality traits studied, only specific gravity, shell weight and thickness differed significantly (p<0.05) in the present study. Fertility was improved significantly ($p{\leq}0.01$) to a dose dependent manner of L-AA. The findings of the present study concluded that dietary L-AA can be a caring management practice at least in part to alleviate the adverse effect of cold induced stress on production performance in Japanese quail.
Kim, H.S.,Yadav, P.,Patel, M.,Kim, H.,Pandey, K.,Kim, J. North-Holland ; Elsevier Science Ltd 2016 Solar energy materials and solar cells Vol.154 No.-
The present work describes a method for the development of an efficient silver nanowire (AgNWs) embedded indium tin oxide (ITO) based silicon heterojunction solar cell. The working mechanism of the heterojunction solar cell is studied by using the current-voltage (J-V) and Impedance spectroscopy (IS) techniques. The charge transfer mechanism and recombination process of the solar cell were explained by resistance, capacitance and ideality factor derived from both these techniques. A relatively high efficiency has been achieved for AgNWs embedded ITO-Si heterojunction solar cell in which AgNWs network acts as a transparent buried contact. This study also provides a new architecture for various heterojunction solar cells with a simple route of fabrication.
Biosynthesis of a novel fisetin glycoside from engineered Escherichia coli
Pandey, R.P.,Parajuli, P.,Chu, L.L.,Kim, S.Y.,Sohng, J.K. Korean Society of Industrial and Engineering Chemi 2016 Journal of industrial and engineering chemistry Vol.43 No.-
<P>Escherichia coli BL21(DE3)/Delta pgi Delta zwf Delta galU mutant was engineered by overexpressing thymidine diphosphate (dTDP)-D-glucose synthase (tgs), dTDP-D-glucose 4,6-dehydratase (dh), and a sugar aminotransferase (wecE) from different sources to produce a pool of dTDP-4-amino-4,6-dideoxy-D-galactose in the cell cytosol. To this recombinant mutant, two Arabidopsis thaliana glycosyltransferases (ArGT-3 and ArGT-4) were overexpressed to generate two glycosylation platforms (E. coli BL21(DE3)/ Delta pgi Delta zwf Delta galUTDW-3 and E. coli BL21(DE3)/Delta pgi Delta zwf Delta galUTDW-4), which were accessed for the glycosylation of fisetin. As a result, one of the two systems, E. coli BL21(DE3)/Delta pgi Delta zwf Delta galUTDW-3, was able to conjugate 4-amino-4,6-dideoxy-D-galactose sugar at the 3-OH position of fisetin, producing an unnatural fisetin 3-O-4-amino-4,6-dideoxy-D-galactoside. (C) 2016 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.</P>
Pandey, R.P.,Parajuli, P.,Koffas, M.A.G.,Sohng, J.K. Pergamon Press ; Elsevier Science Ltd 2016 BIOTECHNOLOGY ADVANCES Vol.34 No.5
<P>In this review, we address recent advances made in pathway engineering, directed evolution, and systems/synthetic biology approaches employed in the production and modification of flavonoids from microbial cells. The review is divided into two major parts. In the first, various metabolic engineering and system/synthetic biology approaches used for production of flavonoids and derivatives are discussed broadly. All the manipulations/engineering accomplished on the microorganisms since 2000 are described in detail along with the biosynthetic pathway enzymes, their sources, structures of the compounds, and yield of each product. In the second part of the review, post-modifications of flavonoids by four major reactions, namely glycosylations, methylations, hydroxylations and prenylations using recombinant strains are described. (C) 2016 Elsevier Inc. All rights reserved.</P>
A multiwavelength analysis of a collection of short-duration GRBs observed between 2012 and 2015
Pandey, S B,Hu, Y,Castro-Tirado, Ao J,Pozanenko, A S,Sá,nchez-Ramí,rez, R,Gorosabel, J,Guziy, S,Jelinek, M,Tello, J C,Jeong, S,Oates, S R,Zhang, B-B,Mazaeva, E D,Volnova, A A,Minaev, P Yu Oxford University Press 2019 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.485 No.4
<B>Abstract</B><P>We investigate the prompt emission and the afterglow properties of short-duration gamma-ray burst (sGRB) 130603B and another eight sGRB events during 2012-2015, observed by several multiwavelength facilities including the Gran Canarias Telescope 10.4 m telescope. Prompt emission high energy data of the events were obtained by INTEGRAL-SPI-ACS, Swift-BAT, and Fermi-GBM satellites. The prompt emission data by INTEGRAL in the energy range of 0.1-10 MeV for sGRB 130603B, sGRB 140606A, sGRB 140930B, sGRB 141212A, and sGRB 151228A do not show any signature of the extended emission or precursor activity and their spectral and temporal properties are similar to those seen in case of other short bursts. For sGRB 130603B, our new afterglow photometric data constrain the pre-jet-break temporal decay due to denser temporal coverage. For sGRB 130603B, the afterglow light curve, containing both our new and previously published photometric data is broadly consistent with the ISM afterglow model. Modeling of the host galaxies of sGRB 130603B and sGRB 141212A using the LePHARE software supports a scenario in which the environment of the burst is undergoing moderate star formation activity. From the inclusion of our late-time data for eight other sGRBs we are able to: place tight constraints on the non-detection of the afterglow, host galaxy, or any underlying ‘kilonova’ emission. Our late-time afterglow observations of the sGRB 170817A/GW170817 are also discussed and compared with the sub-set of sGRBs.</P>
In vitro single-vessel enzymatic synthesis of novel Resvera-A glucosides
Shin, J.Y.,Pandey, R.P.,Jung, H.Y.,Chu, L.L.,Park, Y.I.,Sohng, J.K. Elsevier Scientific Pub 2016 Carbohydrate research Vol.424 No.-
<P>An in vitro enzymatic glycosylation system is developed for the efficient synthesis of glucosides of 3,5-dihydroxy-N-(4-hydroxyphenyl) benzamide (resvera-A), a chemically synthesized molecule resembling resveratrol in structure. Resvera-A is a pharamacophore-based designed molecule that exhibits antioxidant, antibacterial, anti-inflammatory, and anticancer activities. In this study, an alternative cost-effective uridine diphosphate (UDP) recycling system was established to produce UDP-alpha-D-glucose through a two-step enzyme-catalyzed reaction using easily available cheap sources. This UDP-alpha-D-glucose biosynthesis system was combined with a glycosyltransferase (YjiC, from Bacillus licheniformis)-catalyzed reaction for the synthesis of glucoside derivatives of resvera-A. The side product of the glycosylation reaction, UDP, was used as a precursor for the biosynthesis of UDP-alpha-D-glucose, which is used by YjiC for glycosylation, thus recycling UDP. As a result, two novel molecules, resvera-A 3-O-alpha-D-glucoside (42.33 mg, 2.10 mM, 0.84 mg/mL) and resvera-A 4'-O-alpha-D-glucoside (99.38 mg, 4.87 mM, 1.98 mg/mL), were synthesized within 4 h from 50 mL preparative scale reaction using only 0.1 mM of UDP-alpha-D-glucose, 100 folds lower concentration than the concentration of resvera-A (10 mM) used. Structures of both products were elucidated using liquid chromatography, mass spectroscopy, and nuclear magnetic resonance analysis. (C) 2016 Elsevier Ltd. All rights reserved.</P>
Sui, M.,Pandey, P.,Kunwar, S.,Li, M.-Y.,Zhang, Q.,Lee, J. Elsevier 2016 Superlattices and microstructures Vol.100 No.-
<P><B>Abstract</B></P> <P>The morphological evolution of various Ag nanostructures on <I>c</I>-plane sapphire is systematically investigated through the solid-state-dewetting by the control of annealing temperature between 200 and 950 °C with the Ag films of 60 and 10 nm. Various configurations of Ag nanostructures including Ag voids, wiggly and round nanoparticles are fabricated with the 60 nm due to the annealing temperature dependent surface diffusion, surface energy minimization and Ag sublimation. As a sharp distinction, highly dense semi-spherical nanoparticles are fabricated with the 10 nm set throughout the temperature range due to a much higher dewetting degree induced by the enhanced surface diffusion with a much thinner film. The reflectance spectra shows a spectral shift along with the size variation, i.e. blue shift with the decreased size and vice versa. The reflectance and Raman spectra reveal a sharp distinction between the two sets along with the strong correlation to the nanostructure morphology.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Various configurations of self-assembled Ag nanostructures on c-plane sapphire. </LI> <LI> Single configuration Ag nanoparticles throughout the range with a thinner film. </LI> <LI> Detailed morphology study by SEM and AFM. </LI> <LI> Energy-dispersive X-ray spectroscopy confirmation of consistent sublimation above 650 °C. </LI> <LI> Reflectance and Raman of various configurations of Ag nanostructures. </LI> </UL> </P>
Pandey, R.P.,Parajuli, P.,Gurung, R.B.,Sohng, J.K. IPC Science and Technology Press ; Elsevier Scienc 2016 Enzyme and microbial technology Vol.91 No.-
<P>Escherichia coli BL21 (DE3) was engineered by blocking glucose-1-phosphate utilizing glucose phosphate isomerase (pgi), glucose-6-phosphate dehydrogenase (zwf) and uridylyltransferase (galU) genes to produce pool of four different rare dTDP-sugars. The cytosolic pool of dTDP-L-rhamnose, dTDP-D-viosamine, dTDP-4-amino 4,6-dideoxy-D-galactose, and dTDP-3-amino 3,6-dideoxy-D-galactose was generated by overexpressing respective dTDP-sugars biosynthesis genes from various microbial sources. A flexible glycosyltransferase YjiC, from Bacillus licheniformis DSM 13 was also overexpressed to transfer sugar moieties to 3-hydroxyl group of 3-hydroxyflavone, a core unit of flavonoids. Among four rare dTDP-sugars generated in cytosol of engineered strains, YjiC solely transferred L-rhamnose from dTDP-L-rhamnose and tuned to rhamnosyltransferase. (C) 2016 Published by Elsevier Inc.</P>