Browsing by Author "Manoj Kumar Pandey"

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Amyloidogenic Propensity of Metabolites in the Uric Acid Pathway and Urea Cycle Critically Impacts the Etiology of Metabolic Disorders
(American Chemical Society, 2024) Monisha Patel; Ankita Jaiswal; Anam Naseer; Ankita Tripathi; Aayushi Joshi; Tarun Minocha; Aanand Kautu; Shilpi Gupta; Khashti Ballabh Joshi; Manoj Kumar Pandey; Randhir Kumar; Kshatresh Dutta Dubey; Aamir Nazir; Sandeep Verma; Nidhi Gour
Novel insights into the etiology of metabolic disorders have recently been uncovered through the study of metabolite amyloids. In particular, inborn errors of metabolism (IEMs), including gout, Lesch-Nyhan syndrome (LNS), xanthinuria, citrullinemia, and hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome, are attributed to the dysfunction of the urea cycle and uric acid pathway. In this study, we endeavored to understand and mechanistically characterize the aggregative property exhibited by the principal metabolites of the urea cycle and uric acid pathway, specifically hypoxanthine, xanthine, citrulline, and ornithine. Employing scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM), we studied the aggregation profiles of the metabolites. Insights obtained through molecular dynamics (MD) simulation underscore the vital roles of π-π stacking and hydrogen bonding interactions in the self-assembly process, and thioflavin T (ThT) assays further corroborate the amyloid nature of these metabolites. The in vitro MTT assay revealed the cytotoxic trait of these assemblies, a finding that was substantiated by in vivo assays employing the Caenorhabditis elegans (C. elegans) model, which revealed that the toxic effects were more pronounced and dose-specific in the case of metabolites that had aged via longer preincubation. We hence report a compelling phenomenon wherein these metabolites not only aggregate but transform into a soft, ordered assembly over time, eventually crystallizing upon extended incubation, leading to pathological implications. Our study suggests that the amyloidogenic nature of the involved metabolites could be a common etiological link in IEMs, potentially providing a unified perspective to study their pathophysiology, thus offering exciting insights into the development of targeted interventions for these metabolic disorders. © 2024 American Chemical Society.
Variability in Indian isolates of Sclerotium rolfsii by SDS-PAGE
(2013) Rachna Pandey; Manoj Kumar Pandey; Udai Pratap Singh
The variability among 14 different Indian isolates of Sclerotium was studied on the basis of protein profile generated by Polyacrylamide Gel-Electrophoresis (SDS-PAGE). Different characteristics taken into account while studying the variability were sclerotia formation, non-formation, basidial stage formation and non-formation and type of disease symptom, viz. spotted leaf rot and collar rot. A comparison was done between mycelium of the different isolates as well as the sclerotia of the same isolate. All the 14 isolates showed a significant variation among themselves with respect to number and intensity of major and minor bands. It was intriguing to note that isolate L-Brl showed quiet different pattern from the rest of the isolates. A strong induction of a protein band of ~15 kDa, probably responsible for the sclerotial development, was observed on comparing the protein profile of mycelium with the protein profile of sclerotia of all the isolates taken into consideration. A 66 kDa protein was prominently present in the isolate (L-Sph) which invariably forms basidiospores, but this protein was not present in the mycelial protein profile. A protein band with molecular weight greater than 98 kDa was prominently present in the total protein profile of isolates which does not form sclerotia in its life cycle. Furthermore, a protein band of ~12 kDa was consistently present in the isolate which causes collar rot and this protein was absent in isolates which cause spotted leaf rot. Two closely placed distinct protein bands of 43 kDa and 46 kDa were invariably present in all the isolates causing spotted leaf rot. The dendrogram constructed with the help of protein profile so obtained was found to be divided into two prominent clusters. The representative isolate (L-Sph) was also investigated for pectinase, cellulase and xylanase production. The presence of hydrolytic enzymes is significant for contributing pathogenicity to the fungus. © 2013 Copyright Taylor and Francis Group, LLC.