Biology subjects

Alwin Prem Anand, A.

Publications and source records attributed to Alwin Prem Anand, A..

3 recordsLinked to original sources

bioRxiv2026

Comparative analysis of polymerase chain reaction (PCR) assays in detection of Orientia tsutsugamushi from mite vectors

Orientia tsutsugamushi is the causative agent of scrub typhus infection in humans. This pathogen is transmitted into mammalian hosts including humans through Leptotrombidium mites. Till date, detection of O. tsutsugamushi in human was performed using PCR assay with 56kDa type specific antigen (TSA56), 47kDa outer membrane protein (47kDa-OMP) and groEL chaperonin gene. To understand the efficiency of different genes for the detection of O. tsutsugamushi in Leptotrombidium mites, we performed a comparative PCR assay with various universal primers targeting different genes including TSA56, 47kDa-OMP and groEL gene. We have collected 500 Leptotrombidium mites from Vellore, Tamil Nadu and, the mites were segregated into 50 pools with 10 mites in each pool were used for DNA extraction. The molecular detection of O. tsutsugamushi was performed using PCR assays (including conventional, nested and duplex PCR). The comparative PCR analysis showed nested PCR of groEL gene has high efficiency in detecting the presence of O. tsutsugamushi in chigger samples compared to other genes. Interestingly, groEL target demonstrated high efficiency for detection of O. tsutsugamushi in chigger samples and, when used with nested primers, can facilitate differentiation of O. tsutsugamushi from other rickettsial pathogens. Thus, we conclude groEL gene nested PCR assay can be used routinely to detect O. tsutsugamushi in trombiculid mites.

microbiology↗

bioRxiv2020

First report on the presence of natural Wolbachia population from major malarial vector mosquitoes Anopheles culicifacies s.l., and Anopheles stephensi from Tamil Nadu, India

Wolbachia is an alpha-proteobacteria present in several arthropods. The present study focussed on the identification of Wolbachia in Anopheles culicifacies s.l., and Anopheles stephensi, which are wild malarial vector mosquitoes in India. A total of four hundred and eighty seven adult female mosquito samples were collected using taxonomic keys and confirmed by molecular analysis where 48.25% was Anopheles culicifacies s.l., and 51.75% was Anopheles stephensi. The presence of Wolbachia was identified using 16S rRNA, wsp and FtsZ genes, where nested PCR of 16S rRNA alone was successful and sequenced. Only seven mosquitoes (1.4%) were positive for Wolbachia. In silico and restriction digestion of 16S rRNA gene product using RsaI enzyme showed that the identified Wolbachia belongs to supergroup B, which is further supported by phylogenetic analysis. Low prevalence rate of natural Wolbachia was observed in An. culicifacies s.l. (1.7%) and An. stephensi (1.2%). This is the first report on the presence of Wolbachia in Anopheles culicifacies s.l. and Anopheles stephensi.

microbiology↗

bioRxiv2018

In vivo cloning of β 1-4 endoglucanase gene of Serratia liquefaciens using Muduction and its in silico analysis

Cellulose is the major structural component in the plant cell wall. The bio-degradation of cellulose molecules is facilitated by cellulase. In the present study, in vivo cloning of cellulase ({beta}-1, 4 endoglucanase) gene from a cellulolytic bacterium Serratia liquefaciens into E. coli DH5 has been performed using mini-Mu phage transduction. The enzyme activity of cloned endoglucanase was 81.2U/mg at optimum temperature (40{degrees}C) and 80.2U/mg at optimum pH7, while the wildtype has 65.9U/mg and 64.9U/mg respectively. The conserved domain analysis shows that S. liquefaciens endoglucanase belongs to GH8 family. The nucleotide sequence analysis of wildtype and cloned endoglucanase shows that mutations were found at residues 51(Lys - Asn), 203(Trp-Cys), 246(Thr-Iso), 260(Gly-Ala) and 288(Phe-Leu). The structural analysis shows the active site of wildtype endoglucanase is a narrow groove which lies parallel to the central axis, whereas cloned endoglucanase is broad and tilted to [~]70{degrees} from the central axis. The increased enzyme activity in the cloned endoglucanase is due to the structural modification conferred by changes in amino acid resulting in widening of the cleft in the active site.

microbiology↗