Browsing by Author "G. Pal"

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Analysing the phytochemistry and anti-oxidant property of fabricated silver nanoparticles using Catharanthus roseus leaf extract
(World Research Association, 2021) A.K. Keshari; S. Saxena; G. Pal; V. Srivashtav; R. Srivastav
A green rapid biogenic synthesis of silver nanoparticles (AgNPs) using Catharanthus roseus leaf extract was performed. Synthesized nanoparticles were characterized using UV-Visible, Fourier transform infra-red (FTIR) and X-ray diffraction (XRD). The reduction of silver ions to AgNPs using C. roseus extract was completed within 240 mins. The formation of AgNPs was confirmed by Surface Plasmon Resonance (SPR) at 442 nm using UV-Vis Spectrophotometer and it is characterized by XRD, Transmission electron microscope (TEM) and Scanning electron microscope (SEM). The morphological studies revealed the spherical shape of the particles with sizes ranging from 16-35 nm and Energy dispersive X-ray (EDX) spectrum confirmed the presence of silver along with other elements in the plants metabolite. The extracellular AgNPs synthesis by aqueous leaf extract demonstrates ultra-fast, simple and inexpensive method comparable to other methods. The antioxidant assay of the synthesized AgNPs indicated that they have a strong antioxidant property as compared to the control. Since these compounds are also safe to use and discharged into the environment, the green AgNPs could be considered as an innovative alternative approach for biomedical and nanoscience based industries. © 2021 World Research Association. All rights reserved.
Assessment of Bioactive Potential and Characterization of an Anticancer Compound from the Endophytic Fungi of Ocimum sanctum
(Pleiades Publishing, 2024) A. Verma; K. Kumar; U. Talukdar; G. Pal; D. Kumar; P. Shukla; S. Patel; A. Kumar; A. Kumar; R.N. Kharwar; S.K. Verma
Abstract: The goal of this study was to isolate endophytic fungi from Ocimum sanctum L. and to evaluate their biological potential, including antibacterial, antioxidant, and enzymatic activities and further characterization of the bioactive compounds. Nine endophytic fungi were isolated from the leaves and stem tissues of O. sanctum collected from the botanical garden of Banaras Hindu University, Varanasi, India. All isolates were identified based on their microscopic structures and molecular sequencing of the ITS rDNA. Aspergillus clavatonanicus (SS7) and Cochliobolus hawaiiensis (SL3) showed the highest colonization frequencies in the stem and leaves (16 and 14%, respectively). All fungal isolates were tested for extracellular enzymatic activities of amylase, cellulase, and pectinase. Of the nine fungal isolates, 60% tested positive for amylase and cellulase, whereas 50% showed pectinase activity. Using a disc diffusion assay, the extracted secondary metabolites were checked for antibacterial activity against three human pathogenic bacteria. Two isolates, SL2 and SS7, exhibited the highest antibacterial activity against all pathogens, including Enterococcus faecalis, Klebsiella pneumoniae, and methicillin-resistant Staphylococcus aureus (MRSA). Crude extracts of the six fungal isolates showed positive antioxidant activity. The crude extract of Aspergillus allahabadii (isolate SL2) showed strong antibacterial and antioxidant activities and crystallized during purification. X-ray crystallography confirmed the identity of the crystal as citrinin, which also exhibited strong anticancer activity against Dalton’s lymphoma cells. The results of this study suggest that endophytic fungi isolated from the leaf and stem tissues of Ocimum sanctum are potential sources of antibacterial, antioxidant, and anticancer compounds. © Pleiades Publishing, Ltd. 2024. ISSN 0026-2617, Microbiology, 2024, Vol. 93, No. 4, pp. 459–471. Pleiades Publishing, Ltd., 2024.
Endophyte roles in nutrient acquisition, root system architecture development and oxidative stress tolerance
(John Wiley and Sons Inc, 2021) S.K. Verma; P.K. Sahu; K. Kumar; G. Pal; S.K. Gond; R.N. Kharwar; J.F. White
Plants associate with communities of microbes (bacteria and fungi) that play critical roles in plant development, nutrient acquisition and oxidative stress tolerance. The major share of plant microbiota is endophytes which inhabit plant tissues and help them in various capacities. In this article, we have reviewed what is presently known with regard to how endophytic microbes interact with plants to modulate root development, branching, root hair formation and their implications in overall plant development. Endophytic microbes link the interactions of plants, rhizospheric microbes and soil to promote nutrient solubilization and further vectoring these nutrients to the plant roots making the soil-plant-microbe continuum. Further, plant roots internalize microbes and oxidatively extract nutrients from microbes in the rhizophagy cycle. The oxidative interactions between endophytes and plants result in the acquisition of nutrients by plants and are also instrumental in oxidative stress tolerance of plants. It is evident that plants actively cultivate microbes internally, on surfaces and in soils to acquire nutrients, modulate development and improve health. Understanding this continuum could be of greater significance in connecting endophytes with the hidden half of the plant that can also be harnessed in applied terms to enhance nutrient acquisition through the development of favourable root system architecture for sustainable production under stress conditions. © 2021 The Society for Applied Microbiology