Browsing by Author "Ravindra Nath Kharwar"

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A Focused Review of the Pharmacological Potentials of Terrein as an Anticancer Agent
(SAGE Publications Inc., 2023) Jyoti Goutam; Gunjan Sharma; Vandana Yadav; Gauri Pathak; Ravindra Nath Kharwar; Divakar Sharma
Terrein is one of the most important biomolecules of fungal origin being studied from a medicinal perspective. Secondary metabolites are the intermediate products produced during the metabolism of organisms for a large number of functions, for example, defense and communication signals. From the outset, terrein has largely been studied as an anticancer secondary biomolecule. Aspergillus terreus is the only fungal source of some valuable drugs and mycotoxins. From the beginning, a few species of Aspergillus were known to be viable chemical factories. Terrein is a potent biological molecule present in the fungus that is responsible for its medicinal and agricultural values. Numerous evaluations conducted on terrein showed it to have marked biological activities (antimicrobial, antiproliferative, anti-oxidative, and others). To date, terrein has emerged as a very attractive therapeutic regimen against cancer due to its dual targeting nature; tumor angiogenesis and cell proliferation. This focused review provides details of the therapeutic value of terrein and its modes of action as an anticancer agent. Besides this, terrein has other marked bioactivities and manifold uses in the field of medicine, which have also been discussed here. © The Author(s) 2023.
Antioxidant and cytotoxic activity of Rutin isolated from Nigrospora sphaerica, an Euphorbia hirta based endophytic fungus
(Elsevier Ltd, 2024) Veer Singh Gautam; Puja Kumari; Pradip Kumar Jaiswara; Ajay Kumar; Ravindra Nath Kharwar
The objective of this study was to isolate and characterize rutin from the endophytic Nigrospora sphaerica of Euphorbia hirta L. The compound was isolated and purified through thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC). Further, it was identified as rutin (RN) using fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and high resolution mass spectroscopy (HRMS) analyses. The estimated RN concentration in the culture filtrate of N. sphaerica was 19.54 mg/L. The calculated IC50 values of RN with respect to antioxidant potential estimated using 2, 2-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), hydrogen peroxide (H2O2), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and nitric oxide (NO) approaches were 29.1, 36.5, 42.2 and 43.4 µg/mL, respectively. Besides, a combined treatment of RN and cisplatin (CP) inhibited the survival of tumor cells (HuT-78) significantly (P<0.05). Interestingly, the RN enhanced the apoptosis-inducing ability of CP considerably. In conclusion, N. sphaerica may be exploited as an alternative source of rutin for various commercial applications. © 2024 Elsevier Ltd
Bioactive potential evaluation and purification of compounds from an endophytic fungus Diaporthe longicolla, a resident of Saraca asoca (Roxb.) Willd.
(Springer Science and Business Media Deutschland GmbH, 2021) Jay Hind Nishad; Arti Singh; Veer Singh Gautam; Puja Kumari; Jitendra Kumar; Monika Yadav; Ravindra Nath Kharwar
An endophytic fungus (L3), isolated from the leaf tissues of Saraca asoca was identified as D. longicolla by microscopic and molecular methods. The crude extracts of D. longicolla revealed to harbor seven compounds in GC–MS analysis which was subjected to a thin layer chromatography (TLC) for purification and separation of bioactive ingredients. The partially purified fraction from TLC displayed the presence of 2-tridecene (Z) (RT-14.50), 5-tridecene (E) (RT-16.65) and 2,4-di-tert-butylphenol (RT-13.92) in GC–MS. High-performance liquid chromatography (HPLC) was performed to further purify the constituents which led to the collection of 2,4-di-tert-butyl phenol (RT-2.34) with excellent antioxidant activity and antibacterial activity against methicillin resistance Staphylococcus aureus (MRSA). © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Colletotrichum gloeosporioides (endophytic fungi) mediated biosynthesis of TiO2 nanoparticles for high-performance dye-sensitized solar cell
(Elsevier B.V., 2025) Sakshi Singh; Shubham Sharma; Rajnish Bharti; Ravindra Nath Kharwar; Pankaj Kumar Srivastava
This work reports an environmentally friendly protocol for synthesizing TiO2 nanoparticles (NPs) by utilizing endophytic fungi, Colletotrichum gloeosporioides (C. gloeosporioides). The fungi isolated from Thevetia peruviana, worked as a bio-capping agent to regulate the growing TiO2 NPs morphology and agglomeration behavior. The formation of TiO2 NPs was validated by surface plasmon resonance, observed using UV–vis spectroscopy. Using XRD and HRTEM, the structure, size, and shape of the as-synthesized anatase TiO2 NPs were characterized. BET analysis was used to examine the surface area and porosity. EIS revealed the greater charge collection efficiency and enhanced electron lifetime for the TiO2 obtained with N-3 (endophytic fungal extract). The dye-sensitized solar cell (DSSC) fabricated with bio-capped TiO2 (N-3) photoanode exhibited greater light-to-current conversion efficiency, 3.50 %; much enhanced compared to 0.98 % obtained with un-capped TiO2 NPs (N-1) based cell. The study demonstrated that the endophytic fungus C.gloeosporioides played a vital role in enhancing the cell performance. © 2024 The Authors
Editorial: Epigenetic Remodeling of Microorganisms of Pharmaceutical and Industrial Importance
(Frontiers Media S.A., 2022) Vijay K. Sharma; Ravindra Nath Kharwar
[No abstract available]
Effect of the Histone Methyltransferase Specific Probe BRD4770 on Metabolic Profiling of the Endophytic Fungus Diaporthe longicolla
(Frontiers Media S.A., 2021) Jay Hind Nishad; Arti Singh; Rajnish Bharti; Priyanka Prajapati; Vijay Kumar Sharma; Vijai Kumar Gupta; Ravindra Nath Kharwar
The endophytic fungus Diaporthe longicolla was isolated from the stem of Saraca asoca (Roxb.) Willd., commonly known as Ashok plant in India and Sri Lanka. Since no reports are available regarding epigenetic modulations by BRD4770 in microbial entities, D. longicolla was treated with different concentrations of BRD4770 for this purpose and evaluated for its antioxidant and antibacterial potential against five human pathogenic bacteria, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), Shigella boydii, Klebsiella pneumoniae, and Escherichia coli. The crude extract obtained from cultures treated with 100 nM concentration of BRD4770 showed increased antioxidant activity and inhibition zone against S. aureus and MRSA, compared to the non-treated control. The composition of the non-treated and treated crude extract was analyzed, and induced compounds were identified with the help of Gas chromatography–mass spectrometry (GC-MS) and LC-ESI-MS/MS. LC-ESI-MS/MS analysis showed that berberine (antibacterial)-, caffeine-, and theobromine (antioxidant)-like compounds were induced in the BRD4770-treated crude extract. The presence of particular absorbance at a wavelength of 346.5 nm for berberine, 259.4 nm for caffeine, and 278.4 nm for theobromine in the reverse-phase high-performance liquid chromatography (HPLC) analysis of both BRD4770-treated crude metabolites and standard solution of the above compounds strongly supported the increased antibacterial and antioxidant activities that may be due to inducing the alterations in bioactivities of the BRD4770-treated culture. © Copyright © 2021 Nishad, Singh, Bharti, Prajapati, Sharma, Gupta and Kharwar.
Efficacy of chemically characterized Ocimum gratissimum L. essential oil as an antioxidant and a safe plant based antimicrobial against fungal and aflatoxin B1 contamination of spices
(2011) Bhanu Prakash; Ravindra Shukla; Priyanka Singh; Prashant Kumar Mishra; Nawal Kishore Dubey; Ravindra Nath Kharwar
The paper reports the essential oil (EO) of Ocimum gratissimum as plant based preservative and recommends its application as a nontoxic antimicrobial and antiaflatoxigenic agent against fungal and aflatoxin contamination of spices as well their shelf life enhancer in view of its antioxidant activity. The EO exhibited antifungal activity against fungal isolates from some spices and showed better efficacy as fungitoxicant than prevalent fungicide Wettasul-80. The EO also completely checked the aflatoxin B1 (AFB1) synthesis by the toxigenic strains LHP-6 and LHP-10 of A. flavus isolated from Piper nigrum and Myristica fragrans respectively at 0.6μl/ml and 0.5μl/ml, respectively. In addition, EO showed antioxidant activity through DPPH free radical scavenging and β-carotene-linoleic acid bleaching assay. Methyl cinnamate (48.29%) and β-terpinene (26.08%) were recorded the major components of the oil through GC-MS analysis. The EO was found non-mammalian toxic showing high LD50 (11622.67μl/kg) during oral toxicity on mice. © 2010 Elsevier Ltd.
Efficient Production of the Potent Antimicrobial Metabolite “Terrein” From the Fungus Aspergillus terreus
(SAGE Publications Inc., 2020) Jyoti Goutam; Ravindra Nath Kharwar; Vinod Kumar Tiwari; Ranjana Singh; Divakar Sharma
The endophytic fungus Aspergillus terreus (JAS-2) derived from Achyranthes aspera possesses multiple bioactive metabolites, one of which is terrein, a potent antimicrobial substance. Here we report the improved biosynthesis of terrein in cultures grown in media with a fixed carbon and modified nitrogen source (4% dextrose, 1% casein) for 15 days, after which pure crystals of terrein were obtained in the culture medium. We suggest that our improved method is effective for improving the quantity and quality of terrein produced. Terrein has shown potent antimicrobial activities against various microbes that may lead to its further use to combat antimicrobial resistance which threatens the community worldwide. © The Author(s) 2020.
Endophytic fungi mediated alleviation of salinity stress in crop plants: an insight and future prospect
(Springer Science and Business Media B.V., 2025) Ravindra Nath Kharwar; Priyanka Prajapati; Shagun Sinha
Salinity is considered one of the most significant abiotic stresses for plants because it reduces agricultural yield by more than 20% of the world’s irrigated land. To resolve this issue, developing of salt-tolerant crops is critical, costly, and time-consuming. Deciphering processes that allow plants to flourish in saline environments may be an alternative. This review describes the effectiveness of endophytic fungi used in crops as supplements to host plants. This is performed by activating antioxidant mechanisms to scavenge ROS, boost beneficial metabolite levels, promote systemic resistance, and control phytohormones during plant development. By regulating ion accumulation, fungal endophyte associations enhance nutrient absorption, maintain ionic homeostasis, maintain a minimal cytosolic Na+/K+ ratio, and restrict Na+ transport to leaves. In the presence of fungal endophytes, transcription factors encoding high-affinity potassium transporter 1 (HKT1) and inward rectifying K+ channels KAT1 and KAT2 increased. Under salt stress, endophytic fungi colonization in plants enhance photosynthetic and water-use efficiency. At the molecular level, fungal endophytes influence the expression of plant genes involved in proline, aquaporin, and auxin production. Fungal endophytes can colonize host plants and help maintain higher water content in plant tissues under stress conditions. However, only limited evidence exists regarding their potential role in regulating plant genes involved in ion transport, such as those encoding Na⁺/H⁺ antiporters or cyclic nucleotide-gated channels. The participation of these cation-proton exchangers and channels in the endophyte-mediated response to salt stress represents a promising area of research. Investigating these mechanisms may uncover novel pathways by which endophyte colonization enhances plant salt tolerance. Future research should prioritize the genetic, molecular, and biochemical processes that underpin this improved stress resistance. © The Author(s), under exclusive licence to Springer Nature B.V. 2025.
Epigenetic Activation of Antibacterial Property of an Endophytic Streptomyces coelicolor Strain AZRA 37 and Identification of the Induced Protein Using MALDI TOF MS/MS
(Public Library of Science, 2016) Jitendra Kumar; Vijay K. Sharma; Dheeraj K. Singh; Ashish Mishra; Surendra K. Gond; Satish K. Verma; Anuj Kumar; Ravindra Nath Kharwar
The endophytic Streptomyces coelicolor strain AZRA 37 was isolated from the surface sterilized root of Azadirachta indica A. Juss., commonly known as neem plant in India. Since only a few reports are available regarding epigenetic modulations of microbial entities, S. coelicolor was treated with different concentrations of 5-azacytidine for this purpose and evaluated for its antibacterial potential against five human pathogenic bacteria (Aeromonas hydrophila IMS/GN11, Enterococcus faecalis IMS/GN7, Salmonella typhi MTCC 3216, Shigella flexneri ATCC 12022 and Staphylococcus aureus ATCC 25923). The crude extract obtained from cultures treated with 25 ìM concentration of 5-azacytidine, was found effective against all five pathogenic bacteria tested while the untreated control was only active against 3 pathogenic bacteria. HPLC analysis of crude compounds from treated cultures showed a greater number of compounds than that of the control. Extraction of whole cell protein and its SDS PAGE analysis showed an additional major protein band in 25 ìM5- azacytidine treated culture and MALDI TOF MS/MS analysis revealed that this protein belongs to the porin family. © 2016 Kumar et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Evaluation of Congo red dye decolorization and degradation potential of an endophyte Colletotrichum gloeosporioides isolated from Thevetia peruviana (Pers.) K. Schum.
(Springer Science and Business Media B.V., 2023) Rajnish Bharti; Monika Yadav; Arti Singh; Puja Kumari; Jay Hind Nishad; Veer Singh Gautam; Ravindra Nath Kharwar
Decolorization and degradation of textile dye by endophytic fungi stand to be a profitable and viable alternative over conventional methods with respect to eco-friendliness, cost-effectiveness, and non-hazardous nature. One of the active fungal endophytes Colletotrichum gloeosporioides isolated from plant Thevetia peruviana (Pers.) K. Schum. was screened for laccase production and Congo red dye decolorization. Various physicochemical parameters like dye concentration, carbon sources, nitrogen sources, temperature, and pH were optimized, and the maximum decolorization (%) was achieved at 100 mg/L of dye concentration (82%), yeast extract (80%), 30 °C temp (80%), glucose (79%), and 7 pH (78%), respectively. SEM image and fungal biomass changes represent that fungus actively participated in the dye decolorization and had less significant effect on biomass. The regenerative ability of fungus C. gloeosporioides after dye decolorization indicated tolerance against the dye and was found to be more advantageous over previous reports of dye decolorization by other endophytic fungi. UV-Vis spectra, TLC, FTIR, and HPLC results confirmed the decolorization and degradation process due to absorption and biodegradation. Phytotoxicity assay depicted that degraded products are less toxic to Phaseolus mungo compared to Congo red. The overall findings showed that C. gloeosporioides possesses a good decolorization and degradation potential against Congo red and this endophyte can be profitably used for dye-containing wastewater treatment. © 2022, Institute of Microbiology, Academy of Sciences of the Czech Republic, v.v.i.
Genetic characterization for lesion mimic and other traits in relation to spot blotch resistance in spring wheat
(Public Library of Science, 2020) Shweta Singh; Vinod Kumar Mishra; Ravindra Nath Kharwar; Neeraj Budhlakoti; Ram Narayan Ahirwar; Dwijesh Chandra Mishra; Sundeep Kumar; Ramesh Chand; Uttam Kumar; Suneel Kumar; Arun Kumar Joshi
Lesion mimic (Lm) mutants display hypersensitive responses (HR) without any pathogen attack; their symptoms are similar to those produced by a pathogen and result in cell death. In wheat, such mutants have been reported to be resistant against leaf rust due to their biotrophic nature. However, Lm mutants tend to encourage spot blotch (SB) disease caused by Bipolarissorokiniana since dead cells facilitate pathogen multiplication. In this study, 289 diverse wheat germplasm lines were phenotyped in three consecutive growing seasons (2012–2015). Genotype data was generated using the Illumina iSelect beadchip assay platform for wheat germplasm lines. A total of 13,589 single-nucleotide polymorphisms (SNPs) were selected andused for further association mapping. Lm was positively associated with Area Under Disease Progress Curve (AUDPC) for SB but negatively with glaucous index (GI), leaf tip necrosis (Ltn) and latent period (LP). Ltn had a negative association with AUDPC and Lm but a positive one with LP. In a genome-wide association study (GWAS), 29 markers were significantly associated with these traits and 27 were an notated. Seven SNP markers associated with Lm were on chromosome 6A; another on 1B was found to be linked with Ltn. Like wise, seven SNP markers were associated with GI; one on chromosome 6A with the others on 6B. Five SNP markers on chromosomes 3B and 3Dwere significantly correlated with LP, while nine SNP markers on chromosomes 5A and 5B were significantly associated with AUDPC for SB. This study is the first to explore the interaction in wheat between Lm mutants and the hemibiotrophic SB pathogen B.sorokiniana. Copyright: © 2020 Singh et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Genome sequencing and annotation of Cercospora sesami, a fungal pathogen causing leaf spot to Sesamum indicum
(Springer Science and Business Media Deutschland GmbH, 2023) Shagun Sinha; Sudhir Navathe; Sakshi Singh; Deepak K. Gupta; Ravindra Nath Kharwar; Ramesh Chand
Cercospora sesami is a plant pathogen that causes leaf spot disease in sesame plants worldwide. In this study, genome sequence assembly of C. sesami isolate Cers 52–10 (MCC 9069) was generated using native paired-end and mate-pair DNA sequencing based on the Illumina HiSeq 2500 platform. The genome assembly of C. sesami is 34.3 Mb in size with an N50 of 26,222 bp and an average GC content of 53.02%. A total number of 10,872 genes were predicted in this study, out of which 9,712 genes were functionally annotated. Genes assigned to carbohydrate-active enzyme classes were also identified during the study. A total of 80 putative effector candidates were predicted and functionally annotated. The C. sesami genome sequence is available at DDBJ/ENA/GenBank, and other associated information is submitted to Mendeley's data. © 2023, King Abdulaziz City for Science and Technology.
IMA Genome - F16: Draft genome assemblies of Fusarium marasasianum, Huntiella abstrusa, two Immersiporthe knoxdaviesiana isolates, Macrophomina pseudophaseolina, Macrophomina phaseolina, Naganishia randhawae, and Pseudocercospora cruenta
(BioMed Central Ltd, 2022) Brenda D. Wingfield; Lieschen De Vos; Andi M. Wilson; Tuan A. Duong; Niloofar Vaghefi; Angela Botes; Ravindra Nath Kharwar; Ramesh Chand; Barsha Poudel; Habibu Aliyu; Martin J. Barbetti; ShuaiFei Chen; Pieter de Maayer; FeiFei Liu; Sudhir Navathe; Shagun Sinha; Emma T. Steenkamp; Hiroyuki Suzuki; Kalonji A. Tshisekedi; Magriet A. van der Nest; Michael J. Wingfield
[No abstract available]
Impact of environmental variables on the isolation, diversity and antibacterial activity of endophytic fungal communities from Madhuca indica Gmel. at different locations in India
(Springer Heidelberg, 2014) Satish K. Verma; Surendra K. Gond; Ashish Mishra; Vijay K. Sharma; Jitendra Kumar; Dheeraj K. Singh; Anuj Kumar; Jyoti Goutam; Ravindra Nath Kharwar
A total of 1,897 isolates of endophytic fungi from Madhuca indica Gmel., representing 40 morphologically distinct fungal taxa were obtained from 2,700 segments of stem, bark and leaf from three different locations (Loc 1, Loc 2 and Loc 3) in Uttar Pradesh, India. Out of 40 taxa, 28 were identified microscopically and the remaining 12 by molecular methods. Coelomycetes (62.41 %) were the most prevalent fungal group followed by hyphomycetes (28.89 %) and ascomycetes (8.70 %). Colonisation frequency (CF) was greater in stem (82.55 %) than in leaf (65.00 %) and bark (63.22 %). Due to the dominance of a few taxa, species richness and Shannon and Simpson diversity indices were lower in stem than in leaf and bark at each location. Interestingly, less rainfall and lower temperatures disfavoured the overall colonisation of fungal endophytes at Loc 2. The stem samples from all locations were very similar in their endophytic composition, whereas bark and leaf samples showed differences. The dominant endophytic fungi isolated were Phomopsis sp. 1 (9.185 %), and Colletotrichum gloeosporioides (7.00 %). Principal component analysis showed 55 % tissue specificity with 51.08 % maximum variance. Antibacterial activity revealed that 58.33 % endophytic fungi were active against at least one or more bacterial pathogens, whereas the crude extract of five endophytic fungi inhibited the growth of five or more than five (50 %) of the pathogens tested. This report illustrates the value of having an adequate sample size from different tissues and different locations for species and chemical diversity in search of novel natural products. © Springer-Verlag Berlin Heidelberg and the University of Milan 2013.
In vitro potential of endophytic fungus Aspergillus terrus (JAS-2) associated with Achyranthus aspera and study on its culture conditions
(AstonJournals, 2016) Jyoti Goutam; Shweta Singh; Ravindra Nath Kharwar; Vijayakumar Ramarai
The present study explores the efficacy of an endophytic fungus from symbiotic plant Achyranthus aspera, an herb of medicinal importance. Considering limitation of secreted fungal metabolites in terms of biologically active molecules; an endeavour was made to increase the amount of secreted active product. Enhanced secretion of active compound was observed by optimizing different parameter of culture conditions. The fungal culture was isolated from stem of Achyranthus aspera and taxonomically identified as Aspergillus terreus. While analysing it's different in vitro potential, culture metabolites showed antibacterial, antifungal and anti-oxidant activity. In order to increase the yield of compound, culture was optimized for different parameters such as carbon and nitrogen sources and extracting solvent. All the optimization was performed based on % inhibition of bacterial growth when challenged with 10 μg/μl metabolite concentration. Among different media used, potato dextrose broth (PDB) and sabouraud's dextrose broth (SDB) proven to be better media for growth of fungus as well as metabolites production. 1% yeast extract and 4% dextrose resulted in higher cell inhibition. Ethyl acetate served as good extracting solvent. © 2016 Goutam J, et al.
Indole-based polymer and its silver nanocomposite as advanced antibacterial agents: Synthetic path, kinetics of polymerization and applications
(2013) Ambika Srivastava; Pooja Singh; Rajesh Kumar; Satish Kumar Verma; Ravindra Nath Kharwar
Atom transfer radical polymerization of 1-allylindole-3-carbaldehyde (AIC) was studied by employing 2-bromoisobutyryl bromide as initiator in toluene. It led to controlled radical polymerization of AIC, with an increase of molecular weight along with the conversion of the monomer, and a relatively narrow molar mass distribution was obtained, as determined by gel permeation chromatography. The living nature of poly(1-allylindole-3-carbaldehyde) (PAIC) was confirmed by the chain extension polymerization whereas 1H NMR analysis showed that the major population of PAIC retained the chain-end functional group. PAIC and its silver nanocomposite were found to be biologically active against some tested bacterial pathogens. Minimum inhibitory concentration tests revealed that PAIC exhibited antibacterial activity against Staphylococcus aureus, Proteus mirabilis and Klebsiella pneumonae whereas PAIC/Ag nanocomposite showed antibacterial activity against Enterococcus faecalis and K. pneumonae. © 2012 Society of Chemical Industry.
Isolation and functional characterization of a fungal plant symbiont Nigrospora sphaerica, associated to Euphorbia hirta L.
(Springer, 2022) Veer Singh Gautam; Jay Hind Nishad; Puja Kumari; Arti Singh; Satish Kumar Verma; Vijay Kumar Sharma; Jitendra Kumar; Ravindra Nath Kharwar
The endophytic fungi are the endosymbiont which play important role in improving host plant fitness and source of plethora of bioactive molecules. Present study includes the assessment of antimicrobial activity, phytochemical analysis and enzymes activity of fungal endophyte EHL2, isolated from leaf tissues of an Indian medicinal plant Euphorbia hirta L. The fungus exhibited the antibacterial and antifungal activities against a broad range of bacterial and fungal pathogens. To the best of our knowledge, this is the first report about the isolation and characterization of endophytic fungus Nigrospora sphaerica (EHL2) recovered from E. hirta L. The minimum inhibitory concentration (MIC) of the crude extract against pathogenic bacteria ranged from 0.45 to 3.14 mg/ml. For antifungal ativity of fungus, the highest percentage of inhibition was observed against Colletotrichum sp. (33.78%) while, minimum activity was noticed against Alternaria solani (16.60%). Preliminary mycochemical analysis revealed the positive tests for alkaloids, phenolics, flavonoids and terpenoids. The results showed that the total phenolic content (TPC) and total flavonoid content (TFC) of crude extracts were 78.11 ± 0.04 mg GAE/g and 235.94 ± 3.06 mg RE/g, respectively. Furthermore, the fungus also produced amylase, cellulase, protease and laccase enzymes. In conclusion, these positive results of mycochemicals and enzymes activity displayed by N. sphaerica of E. hirta provide an opportunity which could be exploited for host protection against pathogens and enzyme production. © 2022, Indian Phytopathological Society.
Mapping of arsenic pollution with reference to paddy cultivation in the middle Indo-Gangetic Plains
(Kluwer Academic Publishers, 2015) Pankaj Kumar Srivastava; Manvi Singh; Manjul Gupta; Nandita Singh; Ravindra Nath Kharwar; Rudra Deo Tripathi; Chandra Shekhar Nautiyal
A detailed field study was carried out to monitor (i) the arsenic contents in irrigation groundwater and paddy soil and (ii) the accumulation of arsenic in the roots and grains of different paddy varieties grown in the arsenic-contaminated middle Indo-Gangetic Plains of Northern India. Results showed the highest arsenic contamination in the irrigation groundwater (312 μg l−1) and in paddy soil (35 mg kg−1) values that were significantly exceeded the recommended threshold values of 100 μg l−1 (EU) and 20 mg kg−1 (FAO), respectively. The paddy soil arsenic content ranged from 3 to 35 mg kg−1 with a mean value of 15 mg kg−1. The soil arsenic content was found to be influenced by the soil texture, carbon, macronutrients, phosphorus, sulfur, hydrolases, and oxidoreductases properties of the paddy soils as revealed in the principal component analyses. Higher root accumulation (>10 mg kg−1) of arsenic was observed in 6 of the 17 paddy varieties grown in the study area. The range of arsenic content accumulated in the paddy roots was 4.1 to 16.2 mg kg−1 dry weight (dw) and in the grains 0.179 to 0.932 mg kg−1 dw. Out of 17 paddy varieties, eight had 0 >.55 mg kg−1 grain arsenic content and were found unsafe for subsistence maximum daily tolerable dietary intake (MTDI) by human beings according to the regulatory standards. © 2015, Springer International Publishing Switzerland.
Mechanically magnified chitosan-based hydrogel as tissue adhesive and antimicrobial candidate
(Elsevier B.V., 2019) Swati Sharma; Rajesh Kumar; Puja Kumari; Ravindra Nath Kharwar; Amarish Kumar Yadav; Srikrishna Saripella
The present article reports the development of chitosan (CS) based hydrogel series by varying the concentration of cross-linking agent i.e. N,N′-methylenebisacrylamide (MBA) (0.8–1.4 wt%) via free-radical polymerization in aqueous medium. SEM image analysis confirmed the presence of porous 3D-network in the hydrogel. Prepared hydrogel series exhibited good tissue adhesive property along with antimicrobial activity against E. coli, K. pneumonia, S. aureus, C. albicans & M. gypseum bacteria with the good MIC (4–20 mm). The adhesive strength of hydrogel was found 14 kPa, which seems to be quite efficient in tissue adhesiveness applications, which was also validated and tested on Drosophila (Oregon-R) tissues, results were promising. Magnified mechanical strength i.e. storage modulus (G′) and loss modulus (G″) were found 106 Pa and 104 Pa, respectively, which makes the hydrogel a potential candidate in the biomedical field. Moreover, CS hydrogel showed good swelling ratio in aqueous medium up to 390% at room temperature. © 2018