Shashi Sharma

Dr. Shashi Sharma

Division of Microbiology, Office of Regulatory Science, CFSAN/US Food and Drug Administration, MD 20740, USA

Research Focus & Metrics

Academic Career Length

18Years (2009-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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22 June 2018 in Frontiers in Bioengineering and Biotechnology
Verified
Journal Article
Open access
PDF file
NTNagarajan Thirunavukkarasu
Nagarajan Thirunavukkarasu
EJEric Johnson
Eric Johnson
SPSegaran Pillai
Segaran Pillai
DHDavid Hodge
David Hodge
LSLarry Stanker
Larry Stanker
SSShashi Sharma
Shashi Sharma
Botulism outbreak due to consumption of food contaminated with botulinum neurotoxins (BoNTs) is a public health emergency. The threat of bioterrorism through deliberate distribution in food sources and/or aerosolization of BoNTs raises global public health and security concerns due to the potential for high mortality and morbidity. Rapid and reliable detection methods are necessary to support clinical diagnosis and surveillance for identifying the source of contamination, performing epidemiological analysis of the outbreak, preventing and responding to botulism outbreaks. This review considers the applicability of various BoNT detection methods and examines their fitness-for-purpose in safeguarding the public health and security goals.


24 December 2014 in Microbiology Resource Announcements
Verified
Journal Article
Open access
PDF file
Narjol Gonzalez-EscalonaNarjol Gonzalez-Escalona
Narjol Gonzalez-Escalona
NTNagarajan Thirunavukkarasu
Nagarajan Thirunavukkarasu
ASAjay Singh
Ajay Singh
MTMagaly Toro
Magaly Toro
EBEric W. Brown
Eric W. Brown
SSShashi Sharma
Shashi Sharma
Here we report the genome sequence of a Clostridium botulinum strain IBCA10-7060 producing botulinum neurotoxin serotype B and a new toxin serotype. Multilocus sequence typing analysis revealed that this strain belongs to a new sequence type, and whole-genome single nucleotide polymorphism analysis showed that this strain clustered with strains in lineage 2 from group I.

7 February 2019 in Scientific Reports
Verified
Journal Article
Open access
PDF file
MMMichael James Mansfield
Michael James Mansfield
TWTravis Gwynn Wentz
Travis Gwynn Wentz
SZSicai Zhang
Sicai Zhang
ELElliot Jeon Lee
Elliot Jeon Lee
MDMin Dong
Min Dong
ADAndrew Charles Doxey
Andrew Charles Doxey
Clostridial neurotoxins (CNTs), which include botulinum neurotoxins (BoNTs) and tetanus neurotoxin (TeNT), are the most potent toxins known to science and are the causative agents of botulism and tetanus, respectively. The evolutionary origins of CNTs and their relationships to other proteins remains an intriguing question. Here we present a large-scale bioinformatic screen for putative toxin genes in all currently available genomes. We detect a total of 311 protein sequences displaying at least partial homology to BoNTs, including 161 predicted toxin sequences that have never been characterized. We focus on a novel toxin family from Chryseobacterium piperi with homology to BoNTs. We resequenced the genome of C. piperi to confirm and further analyze the genomic context of these toxins, and also examined their potential toxicity by expression of the protease domain of one C. piperi toxin in human cells. Our analysis suggests that these C. piperi sequences encode a novel family of metalloprotease toxins that are distantly related to BoNTs with similar domain architecture. These toxins target a yet unknown class of substrates, potentially reflecting divergence in substrate specificity between the metalloprotease domains of these toxins and the related metalloprotease domain of clostridial neurotoxins.

3 May 2023 in Environmental Technology Reviews
Verified
Journal Article
Closed access
MCMridula Chaturvedi
Mridula Chaturvedi
SJSam Joy
Sam Joy
RGRinkoo Devi Gupta
Rinkoo Devi Gupta
SPSangeeta Pandey
Sangeeta Pandey
SSShashi Sharma
Shashi Sharma
Growing population, increasing industrial and agricultural activities have resulted in the exponential release of high concern emerging pollutants into the environment, categorized under endocrine disrupting chemicals (EDCs). The hydrophobic and lipophilic properties of these persisting EDCs comprising of pharmaceuticals, personal care products, pesticides, surfactants, several industrial chemicals result in generation of complexes with soil organic matter favoring their bioaccumulation via food chain. At each trophic level, these cause negative reproductive, developmental, and neurological impacts in both humans and animals even at low concentrations of ng/L to μg/L. In soil, these impose ecotoxicological effects on soil organisms, reduce microbial activity and change the soil’s physio-chemical properties. The present review provides an insight about its chemical fate in the environment with respect to their physiochemical properties, mechanisms and corresponding impacts in ecosystems. To mitigate EDCs, various regulatory frameworks designed around the globe have also been highlighted. Due to the unambiguous identification of EDCs structures and their amounts, the focus of this review has been also directed on the development of various analytical methods for their precise determination. Further, this review highlights the various physical and chemical methods for their removal with main focus towards the use of eco-friendly cost–effective approaches as phytoremediation, microbial remediation using bacteria, algae, yeasts, fungi and enzymatic remediation using ligninolytic enzyme systems of white rot fungi (WRF), generating no or minimum secondary pollutants. The prospects of immobilized microbes and enzymes on suitable nano supports to enhance their sensitivity against negative environmental factors, have also been summarized. GRAPHICAL ABSTRACT

30 November 2017 in Microbiology Resource Announcements
Verified
Journal Article
Open access
PDF file
TWTravis G. Wentz
Travis G. Wentz
TMTim Muruvanda
Tim Muruvanda
SLSara Lomonaco
Sara Lomonaco
NTNagarajan Thirunavukkarasu
Nagarajan Thirunavukkarasu
MHMaria Hoffmann
Maria Hoffmann
SSShashi Sharma
Shashi Sharma
Clostridial neurotoxins, including botulinum and tetanus neurotoxins, are among the deadliest known bacterial toxins. Until recently, the horizontal mobility of this toxin gene family appeared to be limited to the genus Clostridium . We report here the closed genome sequence of Chryseobacterium piperi , a Gram-negative bacterium containing coding sequences with homology to clostridial neurotoxin family proteins.