Browsing by Author "Rajesh K. Sharma"

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Effects of wastewater irrigation on physicochemical properties of soil and availability of heavy metals in soil and vegetables
(2009) Anita Singh; Rajesh K. Sharma; Madhoolika Agrawal; F. Marshall
The present study investigated the impact of irrigation with wastewater on nutritional property and heavy-metal concentrations in the soil and consequent accumulation in vegetables at sites having long-term uses of wastewater for irrigation. Samples of irrigation water, soil, and root and shoot parts of palak plants were analyzed to determine the concentration of heavy metals. Wastewater irrigation led to increases in the total and phytoavailable heavy-metal concentrations in the soil at all the sites. Heavy-metal concentrations in soil under wastewater irrigation were negatively and positively correlated with soil hydrogen potential (pH) and organic carbon (OC), respectively. The enrichment factor and metal pollution index were higher at wastewater-irrigated sites as compared to the clean water-irrigated ones. The study concludes that wastewater irrigation modified the physicochemical properties of the soil, leading to more availability of heavy metals in the soil and consequently to the plant. © Taylor & Francis Group, LLC.
Facile construction of 4H-chromenes via Michael addition of phenols to benzylidene oxobutanoates and their successful conversion into pyranocoumarins
(Elsevier Ltd, 2018) Priyanka; Rajesh K. Sharma; Ray J. Butcher; Diksha Katiyar
An efficient and simple approach for the synthesis of functionalized 4H-chromenes has been developed via acid catalyzed Michael addition of phenols to benzylidene oxobutanoates. Preliminary mechanistic studies were conducted, suggesting that intermediate chroman derivative is initially formed which on dehydration produces final 4H-chromene. The conversion of 4H-chromenes into linear and angular pyranocoumarins is also described. The structural arrangements between the pyran and coumarin rings have been established by X-ray crystallographic analysis and 2D NMR spectroscopy. © 2018 Elsevier Ltd
Invasive Alien Plant Species: An Exploration of Social Aspect and Phytoremediation Acceptability
(Springer Singapore, 2022) Prince K. Singh; Jay S. Yadav; Indrajeet Kumar; Umesh Kumar; Rajesh K. Sharma
Reduction and degradation of several types of soil contaminants such as heavy metals, pesticides, emerging contaminants, etc. are one of the major serious global challenges in the present scenario. For removal of heavy metals from the environment, various physical and chemical methods are used with some limitations like high cost, intensive labor, alteration of soil properties, etc. which make it problematic at application level. In the present time, science offers a green technique, i.e., phytoremediation; plants are capable of uptake, translocate, transform, and immobilize hazardous metals and reduced their toxicity and concentration in the environment. So, there is an increasing interest in utilization of “invasive alien species” among plant’s kingdom in a productive way due to its easy availability, adaptability to changing climate, alternative mode of reproduction, phenotypic plasticity, and allelopathic in nature. These characteristics also make them more suitable for survival in high stress conditions. They can be used not only as a bioresource, but also as a method for the management of heavy metal polluted land. Invasive alien species are also source of medicines, fodders, and biofuel or bioenergy. The present chapter is focused on exploration of invasive alien plant species for various social aspects and phytoremediation of the heavy metal contaminated land. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021.
Mechanism of rLcrV and rYopB mediated Immunosuppression in murine peritoneal macrophages
(2004) Ajit Sodhi; Rajesh K. Sharma; Harsh V. Batra; Urmil Tuteja
Yersinia pestis causative organism of bubonic and pneumonic plague uses type III secretion system for the translocation of effector molecules in to the target host cells. Type III secretion system of Yersinia pestis, secretes Low calcium response V (LcrV) or V antigen and many other Yersinia outer proteins (Yops). LcrV and YopB were initially known as translocator proteins, but recently have been shown to act as effector and regulatory proteins. Macrophages participate actively in immune response by secreting various effector molecules or by phagocytosis in clearing most of the pathogens. We investigated the effect of rLcrV and rYopB (10 μg/ml) on peritoneal macrophages in vitro. It is observed that rLcrV and rYopB inhibited LPS induced TNF-α and NO production in murine peritoneal macrophages. rLcrV and rYopB also inhibited expression of phospho-p38, -p42/44, -JNK MAPKs and transcription factors NFκB, c-fos and c-jun in LPS treated macrophages. The inhibition in the expression of these signaling molecules has been correlated to the inhibition of TNF-α and NO production in macrophages. © 2004 Elsevier Ltd. All rights reserved.
Responses of Abelmoschus esculentus L. (lady's finger) to elevated levels of Zn and Cd
(2010) Rajesh K. Sharma; Shashi Bhushan Agrawal
The paper deals with the accumulation of heavy metals and responses of lady's finger (Abelmoschus esculentus L.) plants grown to elevated levels of zinc (Zn) and cadmium (Cd), applied singly as well as in combination. Results showed that Zn + Cd application increased Zn accumulation in root, stem and leaves of the plant, but Cd accumulation decreased. The magnitude of adverse effects on all the measured parameters was lower under Zn + Cd treatment as compared to the sum of responses to individual treatments of Zn and Cd. Evidently, Zn and Cd exhibited antagonistic behaviour when applied in combination, resulting into reduced accumulation of Cd in plants. © International Society for Tropical Ecology.
Synthesis, Structure Elucidation, Homology Modeling and Antifilarial Activity of 7-Benzamidocoumarin Derivatives
(Wiley-Blackwell, 2019) Priyanka; Neelabh; Neha Tiwari; Rajesh K. Sharma; Poonam Gupta; Sweta Misra; Shailja Misra-Bhattacharya; Ray J. Butcher; Karuna Singh; Diksha Katiyar
A series of 7-benzamidocoumarin derivatives 10–25 starting from 7-amino coumarins 7 and 8 has been synthesized, characterized and evaluated in vitro for antifilarial activity against the human lymphatic filarial parasite, Brugia malayi. Compounds 13 and 20–23 showed permanent paralysis of the worm with 90–95% inhibition of motility of adult worms at 10 μM. All the synthesized compounds were docked on the modeled receptor of Onchocerca volvulus chitinase OvCHT1. Compound 13 with binding energy of −7.95 Kcal/mol showing three hydrogen bonds with the active site of the enzyme emerged as the best inhibitor. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim