Browsing by Author "Om Prakash"

Now showing 1 - 20 of 87

A current review of cypermethrin-induced neurotoxicity and nigrostriatal dopaminergic neurodegeneration
(2012) Anand Kumar Singh; Manindra Nath Tiwari; Om Prakash; Mahendra Pratap Singh
Cypermethrin, a class II pyrethroid pesticide, is used to control insects in the household and agricultural fields. Despite beneficial roles, its uncontrolled and repetitive applications lead to unintended effects in non-target organisms. Cypermethrin crosses the blood-brain barrier and induces neurotoxicity and motor deficits. Cypermethrin prolongs the opening of sodium channel, a major site of its action, leading to hyper-excitation of the central nervous system. In addition to sodium channel, cypermethrin modulates chloride, voltage-gated calcium and potassium channels, alters the activity of glutamate and acetylcholine receptors and adenosine triphosphatases and induces DNA damage and oxidative stress in the neuronal cells. Cypermethrin also modulates the level of neurotransmitters, including gamma-aminobutyric acid and dopamine. It is one of the most commonly used pesticides in neurotoxicology research not only because of its variable responses depending upon the doses, time and routes of exposure and strain, age, gender and species of animals used across multiple studies but also owing to its ability to induce the nigrostriatal dopaminergic neurodegeneration. This article describes the effect of acute, chronic, developmental and adulthood exposures to cypermethrin in experimental animals. The article sheds light on cypermethrin-induced changes in the central nervous system, including its contribution in the onset of specific features, which are associated with the nigrostriatal dopaminergic neurodegeneration. Resemblances and dissimilarities of cypermethrin-induced nigrostriatal dopaminergic neurodegeneration with sporadic and chemicals-induced disease models along with its advantages and pitfalls are also discussed. © 2012 Bentham Science Publishers.
A highly efficient and thermostable α-amylase from soya bean seeds
(2010) Om Prakash; Nivedita Jaiswal
The α-amylase from soya bean seeds was purified by affinity precipitation, resulting in approx. 20-fold purification with approx. 84% recovery. The purified α-amylase had an optimum pH of 5.5, optimum temperature of 75 °C, Arrhenius energy of activation of 6.03 kcal/mol (1 kcal≈4.184 kJ) and a Km of 2.427 mg/ml (starch substrate). The enzyme had maximum substrate specificity for starch. Among the various metal ions tested, Co2+ and Mn2+ were found to be strong activators. The effect of thiol group modifying agents showed that the thiols of soya bean α-amylase are not directly involved in catalysis. The thermostability of the enzyme makes it suitable for starch liquefaction and the detergent industry respectively. © 2010 Portland Press Limited.
A study of NADP+- linked isocitrate dehydrogenase from germinating mung bean (Vigna radiata)
(Society for Plant Biochemistry and Biotechnology, 2004) Pramod Kumar Srivastava; Kavita Pathak; Om Prakash
NADP+- linked isocitrate dehydrogenase has been purified to apparent homogeneity from 36 h germinated mung beans by ammonium sulphate fractionation, heat treatment, acid treatment, and DEAE - Cellulose column chromatography. The enzyme was purified to 150 fold with 15% recovery. The preparation showed single protein band on native PAGE and was free from bound nucleotides and coloured pigments (A280/A260 = 1.4). The molecular weight was found to be 141,000 and was made of four identical subunits (mol wt 36,000). Thermal inactivation at 50, 53, and 55°C revealed simple first order kinetics and t1/2 was found to be 38, 10, and 3 min, respectively. The enzyme exhibited absolute specificity for NADP+ and substrate. The Km for isocitrate and NADP+ was 28.57 μM and 70 μM, respectively. The enzyme appeared to be regulated by various metabolites of Krebs' cycle intermediates.
Acetohydroxamate inhibition of the activity of urease from dehusked seeds of water melon (Citrullus vulgaris)
(Taylor and Francis Ltd., 2004) Om Prakash; Lata Sheo Bachan Upadhyay
Urease from the seeds of watermelon (Citrullus vulgaris) was purified to apparent homogeneity, using two acetone fractionation steps, heat treatment at 48°C and gel filtration through Sephadex G-200. Effect of aceto-hydroxamic acid (AHA) on the activity of the homogeneous enzyme preparation (sp. act. 3000 ± 550 U/mg protein) was investigated. AHA exhibited a concentration-dependent inhibition both in the presence and absence of the substrate. The inhibition was uncompetitive and the Ki was 2.5 mM. Binding of AHA with the enzyme was reversible, as 63% activity could be restored by dialysis. Time-dependent inhibition revealed a monophasic inhibition of the activity. Addition of β-mercaptoethanol (ME) gradually abolished the inhibition. Pre-treatment of native enzyme with 8.0 mM ME for 5 min at 30°C exhibited protection against AHA-induced inhibition. The significance of these observations is discussed. © 2004 Taylor & Francis Ltd.
Activation of Ternary Transition Metal Chalcogenide Basal Planes through Chemical Strain for the Hydrogen Evolution Reaction
(Wiley-VCH Verlag, 2017) Yongshin Kim; Anand P. Tiwari; Om Prakash; Hyoyoung Lee
Catalytically inactive basal planes pose challenges for the efficient hydrogen evolution reaction (HER) in two-dimensional (2 D) transition metal chalcogenide (TMC) nanosheets. Herein, a new hybrid structure is reported in which zero-dimensional TMC nanodots (NDs) are decorated on the basal planes of 2 D nanosheets of TMCs to enhance their catalytic activity towards the HER process. A novel process is developed to fabricate a hybrid Cu2MoS4 (2 D ternary transition metal chalcogenide Cu2MoS4 nanosheets)/MoSe2 (0 D binary transition metal chalcogenide MoSe2 ND) nanostructure by controlling the size of the MoSe2 NDs to enhance the HER activity. In acidic media, this optimal hybrid Cu2MoS4/MoSe2 nanostructure achieves excellent catalytic activity for HER, which exhibits a low overpotential of 166 mV at a current density of 10 mA cm−2, which corresponds to a Tafel slope of 74.7 mV dec−1. In addition, the synthesized hybrid nanostructure shows excellent stability when under acidic medium for 16 h of continuous electrolysis. Therefore, it is suggested that our strategy may open a new path for the design of hybrid nanostructures by using ternary transition metal chalcogenides (TTMCs) with binary transition metal chalcogenides (BTMCs) for alternative non-noble metal catalysts towards HER. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Activation of Ternary Transition Metal Chalcogenide Basal Planes through Chemical Strain for the Hydrogen Evolution Reaction
(Wiley-VCH Verlag, 2017) Yongshin Kim; Anand P. Tiwari; Om Prakash; Hyoyoung Lee
Invited for this month's cover are collaborators from the Institute for Basic Science (South Korea), Sungkyunkwan University (South Korea), and Banaras Hindu University (India). The cover picture shows the two-dimensional layered transition metal chalcogenide for efficient hydrogen evolution. Read the full text of the article at 10.1002/cplu.201700164. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
An organic solvent and surfactant stable α-amylase from soybean seeds
(Acta Biochimica Polonica, 2013) Nivedita Jaiswal; Om Prakash
An organic solvent and surfactant stable a-amylase was obtained from soybean seeds. The direct and indirect effect of various organic solvents (non-polar, polar protic, and polar aprotic) and surfactants on the activity and stability of free enzyme was determined. The enzyme showed a very high catalytic efficiency and stabilization against most of the organic solvents and surfactants tested, except for few. Those organic solvents and surfactants (like chloroform, dimethyl formamide, n-butanol, and Tween 20), which caused an inhibition in enzyme activity, were used to study their effects on immobilized enzyme. The inhibitory effect was found to be decreased in immobilized enzyme as compared to free enzyme indicating that immobilization imparted stability to the enzyme. Moreover, the possibility of reuse of the enzyme in the presence of the organic solvents and surfactants was increased upon immobilization. The stability of soybean a-amylase towards organic solvents and surfactants shows that it is a potential candidate for use in organic-solvent biocatalysis as well as in detergent industries.
Application of response surface methodology for the determination of optimum reaction conditions (Temperature and pH) for starch hydrolysis by α-amylase
(2011) Nivedita Jaiswal; Om Prakash; Mahe Talat; S.H. Hasan; Rajesh Kumar Pandey
α-amylase from soybean seeds was purified to apparent homogeneity by affinity precipitation via entrapment in alginate with 84% recovery and about 20-fold purification. The α-amylase activity and stability was characterized at various pH and temperature. Response Surface Methodology (RSM) using two-level-two-factor full factorial Central Composite Design (CCD) model was employed to optimize process parameters like pH and temperature which affects the kinetics of α-amylase catalyzed hydrolysis of starch. The results predicted by the design were found in good agreement (R2 = 97.85%) with the experimental results indicating the applicability of proposed model. The multiple regression Analysis and ANOVA showed the individual and cumulative effect of pH and temperature on enzyme activity indicating that the activity increased with the increase of pH unto 5.5 and temperature 75°C. Thus, the RSM was successful in determining the optimum reaction conditions for starch hydrolysis by α-amylase. © 2011 Academic Journals Inc.
Biosynthesis of gold nanoparticles using leaf extract of Salvadora persica and its role in boosting urease performance via immobilization
(Springer, 2021) Rajnish Kumar Singh; Jyoti; P.K. Srivastava; Om Prakash
Gold nanoparticles (AuNPs) have attracted attention in research because of their unique properties and opportunities for various applications. Immobilization is one of the major applications which take advantage of the AuNPs properties as they can be easily modified. Present work deals with the green synthesis of cysteine capped gold nanoparticles (Cys-AuNPs) by using Salvadora persica leaf extract. UV–Vis spectrophotometry, Transmission Electron Microscopy (TEM)¸ Fourier Transform Infrared Spectroscopy (FTIR), and X-Ray Diffraction Spectroscopy (XRD) were utilized to characterize the Cys-AuNPs. Further, urease was purified from Cajanus cajan urease by using ion exchange and gel filtration chromatography and its immobilization on Cys-AuNPs was carried out using glutaraldehyde as a cross-linker. Successful immobilization was confirmed by TEM and FTIR. Results showed that immobilization efficiency (IE) was 79% with enzyme loading of 84.37% and optimum pH and temperature for immobilized urease was 8.0 and 70 °C, respectively. Furthermore, immobilized urease was reusable upto 10 continuous cycles and can be stored up to 35 days with the retention of 50% residual activity. Enhanced properties of urease loaded Cys-AuNPs make it a suitable candidate for urea detection in clinical samples. © 2021, Society for Plant Biochemistry and Biotechnology.
Choroidal melanoma metastasizing to maxillofacial bones
(2007) Manoj Pandey; Om Prakash; Anitha Mathews; Nileena Nayak; Krishnankutty Ramachandran
Background: Melanomas are malignant neoplasm of melanocytic origin, commonly seen on skin and various mucous membranes. Melanomas are the commonest intraocular malignant tumour in the adults. Case presentation: A 50-year-old female presented with complains of painless progressive swelling in right cheek region of two months duration. Examination revealed a 6 × 4 cm bony hard swelling in right zygomatic region near and below lateral canthus of right eye with loss of vision. Investigations revealed it to be a choroidal melanoma metastatising to the zygomatic bone. Patient was successfully treated by surgery. Conclusion: Choroidal melanoma, which commonly metastasizes toliver and lungs, never involves the lymph nodes and metastasis to facial bones is rare. Here we report a case of choroidal melanoma metastasizing to maxillofacial bones. © 2007 Pandey et al; licensee BioMed Central Ltd.
Comparative evaluation of different methods for determing nutrient digestibility in buffaloes
(2008) Om Prakash; J. Singh
Ten digestion experiments were conducted in two phases using 6 adult buffaloes (3 fistulated male and 3 female) in each method. In each phase, five methods viz., conventional (a), lignin (b), chromic oxide (Cr2O3) (c), nylon bag (d) and in-vitro (e) were used for the determination of feed digestibility. In phase - I, the animals were fed concentrate mixture alongwith ad libitum feeding of wheat bhusa and in phase - II, concentrate mixture and Lucerne green (Medicago sativa L.) were fed alongwith ad libitum feeding of wheat bhusa. The overall digestibilities of all the feed constituents were slightly higher by conventional method than lignin. In both the methods, the digestibility of dry matter, crude protein, ether extract, crude fibre and neutral detergent fibre were significantly (P<0.01) lower than Cr2O3 method. Nitrogen-free extract and total carbohydrate digestibility were apparently higher in Cr2O3 than other methods. The average digestibility of all the constituents were at per in methods d and e, but were significantly lower (P<0.01) than the values found in rest of the groups.
Coumarin-based photoacid as a dual-state probe for studying proton transfer dynamics from solute to solvents
(Elsevier B.V., 2025) Anas D. Fazal; Trupti D. Solanky; Abhishek R. Patel; Om Prakash; Subhendu Dhibar; Sumit Mohan Kumar; Sumit K. Panja
In present work, we have developed a coumarin based water-soluble photoacid (3-acetyl-7-hydroxy-2H-chromen-2-one: HyCAc) which acts as a dual-state probe for investigating proton transfer processes from solute to solvents at ground and excited state. Intermolecular hydrogen bonding interactions significantly enhance the proton transfer process. A solvent-dependent proton transfer is evident from the relative intensity of the ICT band in UV–Vis spectra at the ground state. Polar aprotic and protic and aprotic solvents participate in the proton transfer from solute to solvent through intermolecular hydrogen bonding interactions at ground state. Additionally, HyCAc exhibits solvent-specific dual fluorescence and photodissociation behavior in solution at excited states. Photodissociation of HyCAc is observed due to the proton transfer process from solute to solvents at excited state. To deepen the mechanistic understanding, we performed Natural Bond Orbital (NBO) analysis to explore intermolecular interactions through second-order perturbation energy calculations. Atoms in Molecules (AIM), Non-Covalent Interaction (NCI) analysis, Electron Localization Function (ELF), and Localized Orbital Locator (LOL) analyses to elucidate the nature of non-covalent interactions and are also carried out to explore solvent-dependent solute–solvent interactions. © 2024
Cypermethrin alters the expression profile of mrnas in the adult rat striatum: A putative mechanism of postnatal pre-exposure followed by adulthood re-exposure-enhanced neurodegeneration
(2012) Manindra Nath Tiwari; Anand Kumar Singh; Sonal Agrawal; Satya Prakash Gupta; Anurag Jyoti; Rishi Shanker; Om Prakash; Mahendra Pratap Singh
Abstract This study was undertaken to investigate the effect of cypermethrin on the expression patterns of mRNAs in the striatum of adulthood alone and postnatal pre-exposed followed by adulthood re-exposed rats using discover chips rat microarrays. The expression patterns of V-akt murine thymoma viral oncogene homolog 1, B-cell lymphoma 2 (BCL-2), BCL-2-associated X protein, caspase 1, caspase 9, death-associated protein 3 and interleukin-1β were validated by the qRT-PCR. The expressions of inducible nitric oxide synthase (iNOS) and major histocompatibility complex (MHC) II were assessed immunohistochemically; however, tumour protein p53 and cytochrome c (mitochondrial and cytosolic) expressions were checked at protein level by western blotting. Cypermethrin differentially regulated 65 transcripts at one or the other stage of exposure and 21 transcripts exhibited more pronounced alterations in the postnatal pre-exposed and adulthood re-challenged rats. The results of qRT-PCR were in accordance with the microarray observations and the expressions of iNOS, p53 and cytosolic cytochrome c and MHC II positivity were increased while the level of mitochondrial cytochrome c was reduced in adulthood treated animals. The effects were more pronounced in the postnatal pre-exposed followed by adulthood re-exposed rats. The results obtained thus suggest that multiple pathways are involved in the neurodegeneration as well as in enhancing the vulnerability of neurons in cypermethrin pre-exposed postnatal animals upon re-exposure during adulthood. ©Springer Science+Business Media, LLC 2012.
Cypermethrin alters the status of oxidative stress in the peripheral blood: relevance to Parkinsonism
(Kluwer Academic Publishers, 2014) Pratibha Tripathi; Ashish Singh; Sonal Agrawal; Om Prakash; Mahendra Pratap Singh
Parkinson’s disease (PD) is a motor scarcity disorder characterized by the striatal dopamine deficiency owing to the selective degeneration of the nigrostriatal dopaminergic neurons. While oxidative stress is implicated in PD, prolonged exposure to moderate dose of cypermethrin induces Parkinsonism. The study aimed to investigate the status of oxidative stress indicators and antioxidant defence system of the polymorphonuclear leukocytes (PMNs), platelets and plasma to delineate the effect of Parkinsonian dose of cypermethrin in the peripheral blood of rats and its subsequent relevance to Parkinsonism. Nitrite content, lipid peroxidation (LPO) and activity of superoxide dismutase (SOD), catalase, glutathione reductase (GR) and glutathione-S-transferase (GST) were measured in the PMNs, platelets and plasma of control and cypermethrin-treated rats in the presence or absence of a microglial activation inhibitor, minocycline or a dopamine precursor containing the peripheral 3,4-dihydroxyphenylalanine decarboxylase inhibitor, named syndopa, employing the standard procedures. The striatal dopamine was measured to assess the degree of neurodegeneration/neuroprotection. Cypermethrin increased nitrite and LPO in the plasma, platelets and PMNs while it reduced the striatal dopamine content. Catalase and GST activity were increased in the PMNs and platelets; however, it was reduced in the plasma. Conversely, SOD and GR activities were reduced in the PMNs and platelets but increased in the plasma. Minocycline or syndopa reduced the cypermethrin-mediated changes towards normalcy. The results demonstrate that cypermethrin alters the status of oxidative stress indicators and impairs antioxidant defence system of the peripheral blood, which could be effectively salvaged by minocycline or syndopa. The results could be of value for predicting the nigrostriatal toxicity relevant to Parkinsonism. © 2014, University of Navarra.
Detection of a Neurotoxin Quinolinic Acid at Ultra-Trace Amount: SERS and DFT Study
(John Wiley and Sons Ltd, 2025) Monalisha Nayak; Chandan Bhai Patel; Om Prakash; Ashish Kumar Singh; Ranjan Kumar Singh
The presence of quinolinic acid (QA) below 100 nM is a normal condition while its increased amount may cause variety of neurodegenerative diseases. The precise detection of QA in trace amounts (nanomolar) is crucial to control its toxic effects. In the present study, the SERS-based detection of QA and its interaction at varying concentrations in human serum is carried out using silver nanoparticle substrates. The analysis of conformational dynamics of QA across different concentrations ranging from 10−3 to 10−9 M has been done. The adsorption mechanism between QA and silver nanoparticles has been studied using DFT, and the detection of QA up to nanomolar concentration is achieved. A significant shift in the SERS spectra of QA is observed between 10−4 and 10−5 M concentration, attributed to changes in adsorption geometry with varying pH and conformational change from zwitterionic QA → neutral QA. These findings are supported by UV–visible spectra, pH measurements, and DFT calculations. © 2025 John Wiley & Sons Ltd.
Effect of biovita-A seaweed extract from Ascophyllum nodosum on yield, yield attributes and nutrient uptake of wheat (Triticum aestivum L.)
(Ecological Society of India, 2013) Om Prakash; R.N. Meena; Lalji Yadav; A. Sen
[No abstract available]
Effect of metal ions, EDTA and sulfhydryl reagents on soybean amylase activity
(2011) Om Prakash; Nivedita Jaiswal; Rajesh Kumar Pandey
Effect of some metal ions, EDTA and sulfhydryl reagents on the activity of partially purified amylase (Sp. Activity 1213 U mg-1 protein) of soybean seeds were studied. Cobalt (II) and Manganese (II) exhibited marked activating effects on the activity, enhancing up to 200% of the initial activity at 2 mM concentration while Mercury (II) ions severely inhibited. Inhibition by mercury and activation by cobalt and manganese were concentration-dependent. However, other metal ions (K+, Ca2+ Mg2+ Al3+ Cu2+, Zn2+ and Fe3+) moderately increased the enzyme activity to a certain extent and then suppressed. Sodium, Cadmium and Nickel had no detectable influence on the activity. EDTA (12.5 mM) was found to be ineffective even for 1 h of incubation at 27°C suggesting that no metal ion is present in the enzyme. No marked inhibition of amylase activity with the sulfhydryl reagents was found. The stability of the enzyme to metal ions as well as EDTA suggests its promising potential for use in detergent industries. © 2011 Academic Journals Inc.
Effect of moisture stress on key physiological traits in brinjal (Solanum melongena L.) cultivars
(Society for Plant Research, 2017) R. Gobu; B. N. Harish Babu; Kailash Chandra; M. Shankar; Om Prakash
Brinjal, commonly called as aubergine or eggplant need to have drought tolerant cultivars. Present investigation was carried out to identify the effect of moisture stress on key physiological traits and to identify the drought tolerant cultivars. Sixty five genotypes were transplanted after 30 days of sowing in three replications for moisture stress and normal conditions in pots having two plants per pot. The observations on plant height, root length, root: shoot ratio, SPAD chlorophyll reading, relative water content and membrane stability index were recorded in both moisture stress and non-stress plants. Change in percent mean under moisture stress conditions compared to non-stress conditions was computed and found that plant height, root length and relative water content was reduced by 30.86, 21.23 and 46.85 percent respectively, whereas root: shoot ratio, membrane stability index and SPAD chlorophyll Reading were increased by 10.19, 4.13 and 14.98 percent respectively in moisture stress condition compared to non-stress condition. Among the 65 genotypes, Pusa Shaymala, IIHR-7, IIHR-322, R-2585, L-3268, Pusa Purple Long, Annamalai, Long Green, Jawahar Brinjal-69, Jawahar Brinjal-64, Pusa Upkar, Early Round, Swarna Shyamali, Arka Shirish and Raidurga Green Round were found to be moisture stress tolerant cultivars. © 2017, SPR, All Rights Reserved.
Effect of Pr- and Nd-doping on structural, dielectric, and magnetic properties of multiferroic Bi0.8La0.2Fe 0.9Mn0.1O3
(American Institute of Physics Inc., 2014) Rahul Singh; G.D. Dwivedi; P. Shahi; D. Kumar; Om Prakash; A.K. Ghosh; Sandip Chatterjee
Bi0.8La0.15RE0.05Fe0.9Mn 0.1O3 (where RE = Pr and Nd) have been prepared via conventional solid state route. The Rietveld refinement of X-ray diffraction patterns shows that both systems crystallize in orthorhombic Pnma space group. Raman modes observed for these two systems indicate that both systems are very close to orthorhombic Pnma structure. Appearance of prominent A1-3 and weak E-2 modes in Bi0.8La0.15Nd0.05Fe 0.9Mn0.1O3 indicate the presence of chemically more active Bi-O covalent bonds (which favors stereochemical activity of Bi lone pair electrons) in comparison to Bi0.8La0.15Pr 0.05Fe0.9Mn0.1O3. Moreover, Bi 0.8La0.15Nd0.05Fe0.9Mn 0.1O3 system shows higher dielectric constant, low dielectric loss, and higher magnetization value in comparison to Bi 0.8La0.15Pr0.05Fe0.9Mn 0.1O3 system. Ferroelectric transition temperature decreases to 460 °C for both systems in comparison to 710 °C of Bi 0.8La0.2Fe0.9Mn0.1O3. The improved dielectric and magnetic response suggests Bi0.8La 0.15Nd0.05Fe0.9Mn0.1O3 a better multiferroic system than Bi0.8La0.15Pr 0.05Fe0.9Mn0.1O3. © 2014 AIP Publishing LLC.
Effect of thiols on the activity of urease from dehusked seeds of watermelon (Citrullus vulgaris)
(2003) Om Prakash; Lata Sheo Bachan Upadhyay
Urease from seeds of watermelon (Citrullus vulgaris) was purified to apparent homogeneity, using two acetone fractionation steps, heat treatment at 48°C and gel filtration through Sephadex G-200. The effect of various thiols like 2-mercaptoethanol (ME), DL-dithiothreitol (DTT), and L-cysteine was investigated. The enzyme was significantly activated by thiol and the order of effectiveness as activator was ME > DTT > cysteine. All the thiols exhibited two peaks of activation, one at lower concentration and another at higher concentration. Time-dependent activation of urease exhibited very rapid activation; about 5.3-fold with 8.0 mM ME and 4.9-fold with 30 μM DTT within 10 min of treatment. Moreover, the inhibition caused by high urea concentration was completely abolished by ME. Cysteine and DTT were ineffective in abolishing high substrate inhibition. Enzyme pretreated with ME also exhibited elevated activity in the urea concentration range of 10-2000 mM. The significance of these observations is discussed. © 2002 Elsevier Science Ireland Ltd. All rights reserved.