Pregnancy - associated human listeriosis: Virulence and genotypic analysis of Listeria monocytogenes from clinical samples

Dharmendra Kumar Soni,Durg Vijai Singh,Suresh Kumar Dubey 한국미생물학회 2015 The journal of microbiology Vol.53 No.9

cccListeria monocytogenes, a life-threatening pathogen, poses severe risk during pregnancy, may cause abortion, fetal death or neonatal morbidity in terms of septicemia and meningitis. The present study aimed at characterizing L. monocytogenes isolated from pregnant women based on serotyping, antibiotic susceptibility, virulence genes, in vivo pathogenicity test and ERIC- and REP-PCR fingerprint analyses. The results revealed that out of 3700 human clinical samples, a total of 30 (0.81%) isolates [12 (0.80%) from placental bit (1500), 18 (0.81%) from vaginal swab (2200)] were positive for L. monocytogenes. All the isolates belonged to serogroup 4b, and were + ve for virulence genes tested i.e. inlA, inlC, inlJ, plcA, prfA, actA, hlyA, and iap. Based on the mice inoculation tests, 20 isolates showed 100% and 4 isolates 60% relative virulence while 6 isolates were non-pathogenic. Moreover, 2 and 10 isolates were resistant to ciprofloxacin and cefoxitin, respectively, while the rest susceptible to other antibiotics used in this study. ERIC- and REP-PCR collectively depicted that the isolates from placental bit and vaginal swab had distinct PCR fingerprints except a few isolates with identical patterns. This study demonstrates prevalence of pathogenic strains mostly resistant to cefoxitin and/or ciprofloxacin. The results indicate the importance of isolating and characterizing the pathogen from human clinical samples as the pre-requisite for accurate epidemiological investigations. Listeria monocytogenes, a life-threatening pathogen, poses severe risk during pregnancy, may cause abortion, fetal death or neonatal morbidity in terms of septicemia and meningitis. The present study aimed at characterizing L. monocytogenes isolated from pregnant women based on serotyping, antibiotic susceptibility, virulence genes, in vivo pathogenicity test and ERIC- and REP-PCR fingerprint analyses. The results revealed that out of 3700 human clinical samples, a total of 30 (0.81%) isolates [12 (0.80%) from placental bit (1500), 18 (0.81%) from vaginal swab (2200)] were positive for L. monocytogenes. All the isolates belonged to serogroup 4b, and were + ve for virulence genes tested i.e. inlA, inlC, inlJ, plcA, prfA, actA, hlyA, and iap. Based on the mice inoculation tests, 20 isolates showed 100% and 4 isolates 60% relative virulence while 6 isolates were non-pathogenic. Moreover, 2 and 10 isolates were resistant to ciprofloxacin and cefoxitin, respectively, while the rest susceptible to other antibiotics used in this study. ERIC- and REP-PCR collectively depicted that the isolates from placental bit and vaginal swab had distinct PCR fingerprints except a few isolates with identical patterns. This study demonstrates prevalence of pathogenic strains mostly resistant to cefoxitin and/or ciprofloxacin. The results indicate the importance of isolating and characterizing the pathogen from human clinical samples as the pre-requisite for accurate epidemiological investigations.

Green and proficient process for industrial-scale preparation of Gymnema sylvestre standardized-extract enriched with Gymnemic acids through polymer-matrix-adsorption to reduce hyperglycemia

Deepak Kumar,Vipin Kumar Singh,Narayan Prasad Yadav,Sudeep Tandon,Karuna Shanker,Chandan Singh Chanotiya,Narendra Kumar,Puja Khare,Anirban Pal,Debabrata Chanda,Dharmendra Saikia,Yusuf Hussain,Abha Mee 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.116 No.-

Gymnema sylvestre is an important medicinal plant, but a method for preparing standardized extractenriched with biomarkers is not available. The practiced crude hydro-alcoholic extracts of G. sylvestrecontained a few percentage of gymnemic acids (GAs). The enrichment of GAs in preprared extracts isessential from a pharmacology point of view. Presently, a scale-up process has been developed forpreparing G. sylvestre standardized extract (Gym-EEXT). Crude extract (Gym-Crude) was prepared in10-kg batches to obtain a yield of 268.1 mg/g, but GAs was merely 9 mg/g (GA-IV 6.7 mg/g, and GAXVII2.3 mg/g) in 30 % ethanol–water solvent at 50 C in 5 h. Further, Gym-Crude was processed throughpolymer-matrix-adsorption techniques for getting Gym-EEXT (150.9 mg/g) with improved percentage ofGAs (>10 %) comprised of deacylgymnemic acid (DGA: 8.9 mg/g), gymnemagenin (2.3 mg/g), GA-IV(78.6 mg/g), and GA-XVII (10.2 mg/g). For safety aspects, the pesticide residues, solvent residues, heavymetal, aflatoxins, and mutagenicity in Gym-EEXT were below the detection limits. Hence, Gym-EEXT wasenriched with GAs, and fully safe with compliance according to USP-561. An insignificant effect of Gym-EEXT on vitals of experimental mice was observed in acute and sub-acute oral-toxicityexperiments. Gym-EEXT significantly improved the blood glucose metabolism, and hence, it potentiallyreduces hyperglycaemia. Unique chromatographic protocols were developed for the isolation of biomarkerson a 1-kg scale from Gym-Crude with yield of gymnemagenin (5.5 %), and DGA (4.6 %). Finally, a novel,scientifically validated, and the scale-up process has been developed for the preparation of Gym-EEXTalong with an exclusive protocol for isolating its biomarkers.

Tuning phase retardation behaviour of nematic liquid crystal using quantum dot

Swadesh Kumar Gupta,Dharmendra Pratap Singh,Rajiv Manohar,Sandeep Kumar 한국물리학회 2016 Current Applied Physics Vol.16 No.1

We here report on the phase retardation behavior of nematic liquid crystal (NLC) doped with CdSe quantum dot (QD). A study of birefringence and relative permittivity in 4-octyl-40-cyanobiphenyl (8CB) NLC and its variation with doping of QDs has been presented. The study shows improvement of NLC ordering after addition of QDs. The observed higher value of birefringence in QD doped NLC system has been attributed to improved alignment due to additional order in NLC by self assembled QDs. The improved order of NLC system has also been explained by a schematic illustration for pristine and QD doped NLC system. Study of relative permittivity has also revealed the ordering effect in QD dispersed NLC system.

A bridged ruthenium dimer (Ru–Ru) for photoreduction of CO2 under visible light irradiation

Anurag Kumar,Pawan Kumar,Aathira M.S.,Dharmendra Pratap Singh,Babita Behera,Suman L. Jain 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.61 No.-

A bridged binuclear complex consisting of two ruthenium units (Ru–Ru) connected through a bridging ligand was synthesized, in which one unit serves as a photosensitizer, while another unit works as a catalyst. The synthesized Ru–Ru photocatalyst was tested for photoreduction of CO2 to give CO and HCOOH under visible light irradiation in the presence of triethanolamine as a sacrificial donor. The yield of CO and HCOOH was found to be 54 ppm and 28 ppm respectively after 12 h of irradiation. Due to the binding of photosensitizer and catalyst units in a single molecule via bridging ligand provides faster and efficient electron transfer from sensitizer to catalyst unit which resulted in the higher activity and better product yields.

Roles of RECQ helicases in recombination based DNA repair, genomic stability and aging.

Singh, Dharmendra Kumar,Ahn, Byungchan,Bohr, Vilhelm A Kluwer Academic Publishers 2009 Biogerontology Vol.10 No.3

<P>The maintenance of the stability of genetic material is an essential feature of every living organism. Organisms across all kingdoms have evolved diverse and highly efficient repair mechanisms to protect the genome from deleterious consequences of various genotoxic factors that might tend to destabilize the integrity of the genome in each generation. One such group of proteins that is actively involved in genome surveillance is the RecQ helicase family. These proteins are highly conserved DNA helicases, which have diverse roles in multiple DNA metabolic processes such as DNA replication, recombination and DNA repair. In humans, five RecQ helicases have been identified and three of them namely, WRN, BLM and RecQL4 have been linked to genetic diseases characterized by genome instability, premature aging and cancer predisposition. This helicase family plays important roles in various DNA repair pathways including protecting the genome from illegitimate recombination during chromosome segregation in mitosis and assuring genome stability. This review mainly focuses on various roles of human RecQ helicases in the process of recombination-based DNA repair to maintain genome stability and physiological consequences of their defects in the development of cancer and premature aging.</P>

Phytochemistry and pharmacological activity of the genus artemisia

Dheeraj Bisht,Deepak Kumar,Dharmendra Kumar,Kamal Dua,Dinesh Kumar Chellappan 대한약학회 2021 Archives of Pharmacal Research Vol.44 No.5

Artemisia and its allied species have beenemployed for conventional medicine in the Northern temperateregions of North America, Europe, and Asia for thetreatments of digestive problems, morning sickness, irregularmenstrual cycle, typhoid, epilepsy, renal problems, bronchitismalaria, etc. The multidisciplinary use of artemisiaspecies has various other health benefi ts that are related toits traditional and modern pharmaceutical perspectives. Themain objective of this review is to evaluate the traditional,modern, biological as well as pharmacological use of theessential oil and herbal extracts of Artemisia nilagirica,Artemisia parvifl ora, and other allied species of Artemisia. It also discusses the botanical circulation and its phytochemicalconstituents viz disaccharides, polysaccharides,glycosides, saponins, terpenoids, flavonoids, and carotenoids. The plants have diff erent biological importance likeantiparasitic, antimalarial, antihyperlipidemic, antiasthmatic, antiepileptic, antitubercular, antihypertensive, antidiabetic,anxiolytic, antiemetic, antidepressant, anticancer, hepatoprotective,gastroprotective, insecticidal, antiviral activities, andalso against COVID-19. Toxicological studies showed thatthe plants at a low dose and short duration are non or lowtoxic. In contrast, a high dose at 3 g/kg and for a longer durationcan cause toxicity like rapid respiration, neurotoxicity,reproductive toxicity , etc. However, further in-depth studiesare needed to determine the medicinal uses, clinical effi cacyand safety are crucial next steps.

Electroosmotic flow of biorheological micropolar fluids through microfluidic channels

Mithilesh Kumar Chaube,Ashu Yadav,Dharmendra Tripathi,O. Anwar Bég 한국유변학회 2018 Korea-Australia rheology journal Vol.30 No.2

An analytical analysis is presented in this work to assess the influence of micropolar nature of fluids in fully developed flow induced by electrokinetically driven peristaltic pumping through a parallel plate microchannel. The walls of the channel are assumed as sinusoidal wavy to analyze the peristaltic flow nature. We consider that the wavelength of the wall motion is much larger as compared to the channel width to validate the lubrication theory. To simplify the Poisson Boltzmann equation, we also use the Debye-Hückel linearization. We consider governing equation for micropolar fluid in absence of body force and couple effects however external electric field is employed. The solutions for axial velocity, spin velocity, flow rate, pressure rise, and stream functions subjected to given physical boundary conditions are computed. The effects of pertinent parameters like Debye length and Helmholtz-Smoluchowski velocity which characterize the EDL phenomenon and external electric field, coupling number and micropolar parameter which characterize the micropolar fluid behavior, on peristaltic pumping are discussed through the illustrations. The results show that peristaltic pumping may alter by applying external electric fields. This model can be used to design and engineer the peristalsis-lab-on-chip and micro peristaltic syringe pumps for biomedical applications.

Molecular docking, QSAR and ADMET studies of withanolide analogs against breast cancer

Yadav, Dharmendra K,Kumar, Surendra,Saloni,Singh, Harpreet,Kim, Mi-hyun,Sharma, Praveen,Misra, Sanjeev,Khan, Feroz Dove Medical Press 2017 Drug design, development and therapy Vol.11 No.-

<P>Withanolides are a group of pharmacologically active compounds present in most prodigal amounts in roots and leaves of <I>Withania somnifera</I> (Indian ginseng), one of the most important medicinal plants of Indian traditional practice of medicine. Withanolides are steroidal lactones (highly oxygenated C-28 phytochemicals) and have been reported to exhibit immunomodulatory, anticancer and other activities. In the present study, a quantitative structure activity relationship (QSAR) model was developed by a forward stepwise multiple linear regression method to predict the activity of withanolide analogs against human breast cancer. The most effective QSAR model for anticancer activity against the SK-Br-3 cell showed the best correlation with activity (<I>r</I><SUP>2</SUP>=0.93 and rCV<SUP>2</SUP> =0.90). Similarly, cross-validation regression coefficient (rCV<SUP>2</SUP>=0.85) of the best QSAR model against the MCF7/BUS cells showed a high correlation (<I>r</I><SUP>2</SUP>=0.91). In particular, compounds CID_73621, CID_435144, CID_301751 and CID_3372729 have a marked antiproliferative activity against the MCF7/BUS cells, while 2,3-dihydrowithaferin A-3-beta-<I>O</I>-sulfate, withanolide 5, withanolide A, withaferin A, CID_10413139, CID_11294368, CID_53477765, CID_135887, CID_301751 and CID_3372729 have a high activity against the Sk-Br-3 cells compared to standard drugs 5-fluorouracil (5-FU) and camptothecin. Molecular docking was performed to study the binding conformations and different bonding behaviors, in order to reveal the plausible mechanism of action behind higher accumulation of active withanolide analogs with β-tubulin. The results of the present study may help in the designing of lead compound with improved activity.</P>

Vision based rail track extraction and monitoring through drone imagery

Arun Kumar Singh,Anushka Swarup,Ankush Agarwal,Dharmendra Singh 한국통신학회 2019 ICT Express Vol.5 No.4

Track detection and gauge measurement are considered as crucial aspects of railway inspection systems. Traditionally, monitoring by human inspectors was done. Nowadays, computer vision-based systems are used due to their flexibility and ease of use. In recent years, various prototypes of vision based inspection system have been proposed, most have a camera mounted on carts or trains. Employing drones for such monitoring systems provides a cost effective and accurate means for monitoring tracks. This paper explores the possibilities of computer vision based monitoring through drone imagery. The experimental results ensure that the proposed method provides high reliability and accuracy.

SWCNT doped ferroelectric liquid crystal : The electro-optical properties with enhanced dipolar contribution

Swadesh Kumar Gupta,Dharmendra Pratap Singh,Rajiv Manohar 한국물리학회 2013 Current Applied Physics Vol.13 No.4

Effect of single wall carbon nanotubes (SWCNTs) on electro-optical performance of a ferroelectric liquid crystal (FLC) has been studied. Voltage dependent spontaneous polarization and response time measurement has been made for the pure and SWCNT doped FLC system. Dielectric measurement has also been performed to understand the existing interaction between SWCNTs and FLC molecules. The results have shown increase in the value of spontaneous polarization and relative permittivity with slight slower response for the doped system. The observed properties of doped system revealed that the SWCNTs can perform well with FLC at low applied electric field to enhance the performance of LC devices.