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201.
Saba Hasan Anis Ahmad Abhinav Purwar Nausheen Khan Rishi Kundan Garima Gupta 《Bioinformation》2013,9(5):238-242
This study investigates the mechanisms as well as strategies for purification and characterization of potential enzymes involved in
pathogenesis of entomopathogenic fungi. The test strain of Verticillium lecanii that was screened, during the present investigation,
proved to be an efficient producer of protein and polysaccharide degrading enzymes (amylase, protease, and lipase), hence
indicating versatility in biochemical mechanisms. Halo zones produced colony growth of V. lecanii on agar confirmed activity of
protease, amylase and lipase enzyme by the V. lecanii isolate. Enzymatic Index (EI) observed were: Protease – 2.195, Amylase-
2.196, Lipase- 2.147. Spectrophotometric analysis of enzymatic activity of V.lecanii at five different pH – 3, 5, 7, 9, 11 revealed that
highest proteolytic activity of the V. lecanii isolate was reported at pH 7 and 9 whereas proteolytic activity was minimum at acidic
pH 3. Maximum amylolytic activity of V. lecanii on the 7th day of inoculation was at pH 3 i.e. in an acidic environment in contrast to
neutral pH 7. Maximum lipolytic activity of V. lecanii was found at pH 7. Since enzyme production in entomopathogenic fungi is
specific and forms an important criterion for successful development as well as improvement of mycoinsecticides, hence a
significant conclusion from the present analysis is the degree of variation in secretion of enzymes in test strain of Verticillium lecanii. 相似文献
202.
The hemochromatosis associated proteins HFE and Transferrin Receptor 2 (TFR2) have been shown to be important for the proper regulation of hepcidin. A number of in vitro studies using transient overexpression systems have suggested that an interaction between HFE and TFR2 is required for the regulation of hepcidin. This model of iron sensing which centers upon the requirement for an interaction between HFE and TFR2 has recently been questioned with in vivo studies in mice from our laboratory and others which suggest that Hfe and Tfr2 can regulate hepcidin independently of each other. To re-examine the postulated interaction between Hfe and Tfr2 we developed a novel expression system in which both proteins are stably co-expressed and used the proximity ligation assay to examine the interactions between Hfe, Tfr1 and Tfr2 at a cellular level. We were able to detect the previously described interaction between Hfe and Tfr1, and heterodimers between Tfr1 and Tfr2; however no interaction between Hfe and Tfr2 was observed in our system. The results from this study indicate that Hfe and Tfr2 do not interact with each other when they are stably expressed at similar levels. Furthermore, these results support in vivo studies which suggest that Hfe and Tfr2 can independently regulate hepcidin. 相似文献
203.
Shariq I. Sherwani Sheila Pabon Rishi B. Patel Muzzammil M. Sayyid Thomas Hagele Sainath R. Kotha Ulysses J. Magalang Krishna R. Maddipati Narasimham L. Parinandi 《Cell biochemistry and biophysics》2013,67(2):317-329
Mercury, especially methylmercury (MeHg), is implicated in the etiology of cardiovascular diseases. Earlier, we have reported that MeHg induces phospholipase D (PLD) activation through oxidative stress and thiol-redox alteration. Hence, we investigated the mechanism of the MeHg-induced PLD activation through the upstream regulation by phospholipase A2 (PLA2) and lipid oxygenases such as cyclooxygenase (COX) and lipoxygenase (LOX) in the bovine pulmonary artery endothelial cells (BPAECs). Our results showed that MeHg significantly activated both PLA2 (release of [3H]arachidonic acid, AA) and PLD (formation of [32P]phosphatidylbutanol) in BPAECs in dose- (0–10 μM) and time-dependent (0–60 min) fashion. The cPLA2-specific inhibitor, arachidonyl trifluoromethyl ketone (AACOCF3), significantly attenuated the MeHg-induced [3H]AA release in ECs. MeHg-induced PLD activation was also inhibited by AACOCF3 and the COX- and LOX-specific inhibitors. MeHg also induced the formation of COX- and LOX-catalyzed eicosanoids in ECs. MeHg-induced cytotoxicity (based on lactate dehydrogenase release) was protected by PLA2-, COX-, and LOX-specific inhibitors and 1-butanol, the PLD-generated PA quencher. For the first time, our studies showed that MeHg activated PLD in vascular ECs through the upstream action of cPLA2 and the COX- and LOX-generated eicosanoids. These results offered insights into the mechanism(s) of the MeHg-mediated vascular endothelial cell lipid signaling as an underlying cause of mercury-induced cardiovascular diseases. 相似文献
204.
Sanjaya Gyawali Stephen M. Neate Tika B. Adhikari Krishna D. Puri Rishi R. Burlakoti Shaobin Zhong 《Journal of Phytopathology》2012,160(11-12):637-646
Common root rot (CRR) and spot blotch, caused by Cochliobolus sativus (Ito and Kurib.) Drechsl. ex Dast., are important diseases of barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) worldwide. However, the population biology of C. sativus is still poorly understood. In this study, the genetic structure of three C. sativus populations, consisting of isolates sampled respectively from barley leaves (BL), barley roots (BR) and wheat roots (WR) in North Dakota, was analysed with amplified fragment length polymorphism (AFLP) markers. A total of 127 AFLP loci were generated among 208 C. sativus isolates analysed with three primer combinations. Gene diversity (H = 0.277–0.335) were high in all three populations. Genetic variation among C. sativus individuals within population accounted for 74%, whereas 26% of the genetic variation was explained among populations. Genetic differentiation was high (ØPT = 0.261, corrected = 0.39), whereas gene flow (Nm) ranged from 1.27 to 1.56 among the three populations analysed. The multilocus linkage disequilibrium (LD) (= 0.076–0.117) was moderate in C sativus populations. Cluster analyses indicate that C. sativus populations differentiated according to the hosts (barley and wheat) and tissues (root and leaf) although generalists also exist in North Dakota. Crop breeding may benefit from combining genes for resistance against both specialists and generalists of C. sativus. 相似文献
205.
Rishi Kishore Vishwakarma Krunal Arvind Patel Prashant Sonawane Somesh Singh Ruby Uma Kumari Dinesh Chandra Agrawal Bashir Mohammad Khan 《Bioinformation》2012,8(22):1075-1081
Farnesyl pyrophosphate synthase (FPS; EC 2.5.1.10) is a key enzyme in isoprenoid biosynthetic pathway and provides precursors
for the biosynthesis of various pharmaceutically important metabolites. It catalyzes head to tail condensation of two isopentenyl
pyrophosphate molecules with dimethylallyl pyrophosphate to form C15 compound farnesyl pyrophosphate. Recent studies have
confirmed FPS as a molecular target of bisphosphonates for drug development against bone diseases as well as pathogens.
Although large numbers of FPSs from different sources are known, very few protein structures have been reported till date. In the
present study, FPS gene from medicinal plant Bacopa monniera (BmFPS) was characterized by comparative modeling and docking.
Multiple sequence alignment showed two highly conserved aspartate rich motifs FARM and SARM (DDXXD). The 3-D model of
BmFPS was generated based on structurally resolved FPS crystal information of Gallus gallus. The generated models were validated
by various bioinformatics tools and the final model contained only α-helices and coils. Further, docking studies of modeled BmFPS
with substrates and inhibitors were performed to understand the protein ligand interactions. The two Asp residues from FARM
(Asp100 and Asp104) as well as Asp171, Lys197 and Lys262 were found to be important for catalytic activity. Interaction of
nitrogen containing bisphosphonates (risedronate, alendronate, zoledronate and pamidronate) with modeled BmFPS showed
competitive inhibition; where, apart from Asp (100, 104 and 171), Thr175 played an important role. The results presented here
could be useful for designing of mutants for isoprenoid biosynthetic pathway engineering well as more effective drugs against
osteoporosis and human pathogens.
Abbreviations
IPP - Isopentenyl Pyrophosphate, DMAPP - Dimethylallyl Pyrophosphate, GPP - Geranyl Pyrophosphate, FPP - FPPFarnesyl Pyrophosphate, DOPE - Discrete Optimized Protein Energy, BmFPS - Bacopa monniera Farnesyl Pyrophosphate Synthase, RMSD - Root Mean square Deviation, OPLS-AA - Optimized Potentials for Liquid Simulations- All Atom, FARM - First Aspartate Rich Motif, SARM - Second Aspartate Rich Motif. 相似文献206.
207.
Kapur S Aistrup GL Sharma R Kelly JE Arora R Zheng J Veramasuneni M Kadish AH Balke CW Wasserstrom JA 《American journal of physiology. Heart and circulatory physiology》2010,299(6):H1843-H1853
Defects in excitation-contraction coupling have been reported in failing hearts, but little is known about the relationship between these defects and the development of heart failure (HF). We compared the early changes in intracellular Ca(2+) cycling to those that underlie overt pump dysfunction and arrhythmogenesis found later in HF. Laser-scanning confocal microscopy was used to measure Ca(2+) transients in myocytes of intact hearts in Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs) at different ages. Early compensatory mechanisms include a positive inotropic effect in SHRs at 7.5-9 mo compared with 6 mo. Ca(2+) transient duration increased at 9 mo in SHRs, indicating changes in Ca(2+) reuptake during decompensation. Cell-to-cell variability in Ca(2+) transient duration increased at 7.5 mo, decreased at 9 mo, and increased again at 22 mo (overt HF), indicating extensive intercellular variability in Ca(2+) transient kinetics during disease progression. Vulnerability to intercellular concordant Ca(2+) alternans increased at 9-22 mo in SHRs and was mirrored by a slowing in Ca(2+) transient restitution, suggesting that repolarization alternans and the resulting repolarization gradients might promote reentrant arrhythmias early in disease development. Intercellular discordant and subcellular Ca(2+) alternans increased as early as 7.5 mo in SHRs and may also promote arrhythmias during the compensated phase. The incidence of spontaneous and triggered Ca(2+) waves was increased in SHRs at all ages, suggesting a higher likelihood of triggered arrhythmias in SHRs compared with WKY rats well before HF develops. Thus serious and progressive defects in Ca(2+) cycling develop in SHRs long before symptoms of HF occur. Defective Ca(2+) cycling develops early and affects a small number of myocytes, and this number grows with age and causes the transition from asymptomatic to overt HF. These defects may also underlie the progressive susceptibility to Ca(2+) alternans and Ca(2+) wave activity, thus increasing the propensity for arrhythmogenesis in HF. 相似文献
208.
209.
210.
Rishi Aryal Guru Jagadeeswaran Yun Zheng Qingyi Yu Ramanjulu Sunkar Ray Ming 《BMC genomics》2014,15(1)