Browsing by Author "Rishi Shanker"

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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.
Enterococci in river Ganga surface waters: Propensity of species distribution, dissemination of antimicrobial-resistance and virulence-markers among species along landscape
(2009) Pushpa Lata; Siya Ram; Madhoolika Agrawal; Rishi Shanker
Background. Surface waters quality has declined in developing countries due to rapid industrialization and population growth. The microbiological quality of river Ganga, a life-sustaining surface water resource for large population of northern India, is adversely affected by several point and non-point sources of pollution. Further, untreated surface waters are consumed for drinking and various household tasks in India making the public vulnerable to water-borne diseases and outbreaks. Enterococci, the 'indicator' of water quality, correlates best with the incidence of gastrointestinal diseases as well as prevalence of other pathogenic microorganisms. Therefore, this study aims to determine the distribution of species diversity, dissemination of antimicrobial-resistance and virulence-markers in enterococci with respect to rural-urban landscape along river Ganga in northern India. Results. Enterococci density (χ2: 1900, df: 1; p < 0.0001) increased from up-to-down gradient sites in the landscape. Species diversity exhibit significant (χ2: 100.4, df: 20; p < 0.0001) and progressive distribution of E. faecalis, E. faecium, E. durans and E. hirae down the gradient. Statistically discernible (p: 0.0156 - < 0.0001) background pool of resistance and virulence was observed among different Enterococcus spp. recovered from five sites in the up-to-down gradient landscape. A significant correlation was observed in the distribution of multiple-antimicrobial- resistance (viz., erythromycin-rifampicin-gentamicin-methicillin and vancomycin-gentamicin-streptomycin; rs: 0.9747; p: 0.0083) and multiple-virulence-markers (viz., gelE+esp+; r s: 0.9747; p: 0.0083; gelE+efaA+; r s: 0.8944; p: 0.0417) among different Enterococcus spp. Conclusion. Our observations show prevalence of multiple-antimicrobial-resistance as well as multiple-virulence traits among different Enterococcus spp. The observed high background pool of resistance and virulence in enterococci in river waters of populous countries has the potential to disseminate more alarming antimicrobial-resistant pathogenic bacteria of same or other lineage in the environment. Therefore, the presence of elevated levels of virulent enterococci with emerging vancomycin resistance in surface waters poses serious health risk in developing countries like India. © 2009 Lata et al; licensee BioMed Central Ltd.
Involvement of multiple molecular events in pyrogallol-induced hepatotoxicity and silymarin-mediated protection: Evidence from gene expression profiles
(2010) Ghanshyam Upadhyay; Manindra Nath Tiwari; Om Prakash; Anurag Jyoti; Rishi Shanker; Mahendra Pratap Singh
In this study, the involvement of various molecular events in pyrogallol-mediated hepatotoxicity was deciphered by differential mRNA transcription profiles of control and pyrogallol treated mice liver. The modulatory effects of silymarin on pyrogallol-induced differentially expressed transcripts were also looked into. Swiss albino mice were treated with or without pyrogallol. In some set of experiments, mice were also treated with silymarin 2. h prior to pyrogallol. Total RNA was isolated from liver and polyadenylated RNA was reverse-transcribed into Cye 3 or Cye 5 labelled cDNA. Equal amounts of labelled cDNA from two different groups were mixed and hybridized with mouse 15. k array. The hybridized arrays were scanned, analyzed and the expression level of each transcript was calculated. The differential expression was validated by quantitative real time polymerase chain reaction. Comparative transcription pattern showed an alteration in the expression of 183 transcripts (150 up-regulated and 33 down-regulated) associated with oxidative stress, cell cycle, cytoskeletal network, cell-cell adhesion, extra-cellular matrix, inflammation, apoptosis, cell-signaling and intermediary metabolism in pyrogallol-exposed liver and silymarin pre-treatment modulated the expression of many of these transcripts. Results obtained thus suggest that pyrogallol induces multiple molecular events leading to hepatotoxicity and silymarin effectively counteracts pyrogallol-mediated alterations. © 2010 Elsevier Ltd.
Q-PCR based culture-independent enumeration and detection of enterobacter: An emerging environmental human pathogen in riverine systems and potable water
(Frontiers Research Foundation, 2016) Chandra B. Patel; Rishi Shanker; Vijai K. Gupta; Ram S. Upadhyay
The availability of safe and pristine water is a global challenge when large numbers of natural and anthropogenic water resources are being depleted with faster rate. The remaining water resources are severely contaminated with various kinds of contaminants including microorganisms. Enterobacter is one of the fecal coliform bacteria of family Enterobacteriaceae. Enterobacter was earlier used as an indicator bacterium along with other fecal Coliforms namely Escherichia coli, Citrobacter, and Klebsiella, but it is now known to cause various diseases in human beings. In this study, we have collected 55 samples from potable water and riverine system and proved their presence using their conserved sequences of 16S rRNA and 23S rRNA genes with the help of SYBR green real-time PCR, which showed very high specificity for the detection of Enterobacter. The Enterobacter counts in potable water were found to 1290 ± 32.89 to 1460 ± 39.42 cfu/100 ml. The Enterobacter levels in surface water were 1.76 × 104 ± 492, 1.33 × 104 ± 334, 1.15 × 104 ± 308, 2.56 × 104 ± 802, 2.89 × 104 ± 962, 8.16 × 104 ± 3443 cfu/100 ml; the levels of Enterobacter contamination associated with hydrophytes were 4.80 × 104 ± 1804, 3.48 × 104 ± 856, 8.50 × 104 ± 2074, 8.09 × 104 ± 1724, 6.30 × 104 ± 1738, 3.68 × 104 ± 949 cfu/10 g and the Enterobacter counts in sediments of the river, were 2.36 × 104 ± 703, 1.98 × 104 ± 530, 9.92 × 104 ± 3839, 6.80 × 104 ± 2230, 8.76 × 104 ± 3066 and 2.34 × 104 ± 732 cfu/10 g at the sampling Site #1, Site #2, Site #3, Site #4, Site #5, and Site #6, respectively. The assay could be used for the regular monitoring of potable water and other water reservoirs to check waterborne outbreaks. © 2016 Patel, Shanker, Gupta and Upadhyay.
Rapid detection of enterotoxigenic Escherichia coli gene using bio-conjugated gold nano-particles
(2011) Anurag Jyoti; Surinder P. Singh; Madhu Yashpal; Premendra D. Dwivedi; Rishi Shanker
In this study, a simple gold nanoparticle based colorimetric detection system for on site diagnostics of Enterotoxigenic Escherichia coli (ETEC) has been developed. The developed assay could detect LT1 gene as evident from UV-visible spectra, the broadening of peak on hybridization of GNP probes with different copy numbers of the target gene.The present study suggests that hybridization induced changes in optical properties of GNPs can be translated into a rapid and simple colorometric" spot and read test detection method for ETEC. Copyright © 2011 American Scientific Publishers All rights reserved.
Real time PCR for the rapid detection of vanA gene in surface waters and aquatic macrophyte by molecular beacon probe
(2009) Pushpa Lata; Siya Ram; Madhoolika Agrawal; Rishi Shanker
Enterococci serve as an "indicator" of fecal contamination for recreational water quality. The vancomycin-resistant-enterococci (VRE) are emerging environmental contaminants in the surface waters. The aim of this study was to develop a rapid and specific molecular beacon probe (MBP)-based real-time PCR assay for detection of vanA gene in surface waters and aquatic macrophyte. The limit of detection (LOD) of the MBP assay was 1 CFU/mL of VRE [r ) 0.943; PCR efficiency ) 99.7%] in 2-fold dilution format within 2.5 h and demonstrated high specificity for environmental enterococci isolates exhibiting VanA phenotype (n ) 25). VRE were detected from downstream surface waters of the rivers impacted by point sources of pollution andrecreationalactivities. TheprobedetectedvanA geneinroot-mat associated microbiota of E. crassipes (Mart.) Solms. an aquatic nuisance weed, at eutrophic sites of the surface waters(ANOVA p < 0.001).Inaddition,theassayenableddetection of otherwise nondetectable vanA gene concentration in the upstream sites of two Indian rivers (Student's t test p < 0.001). The MBP assay developed can be used for sensitive and rapid detection of VRE in surface waters and identification of nonpoint sources of pollution for implementation of preventive measures to protect human health. © 2009 American Chemical Society.