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Kolkata, India

Singh A.,National Analysis Center | Singh A.,Temple University | Kashyap V.K.,National Analysis Center
Interdisciplinary Perspectives on Infectious Diseases | Year: 2012

Background. Tuberculosis, a global health problem and highly prevalent in India, has always been a serious problem with respect to definitive diagnosis. Polymerase chain reaction (PCR) techniques are now widely used for early detection and species differentiation of mycobacteria, but mostly with their own limitations. We aim to detect and differentiate Mycobacterium tuberculosis (Mtb) infections by choosing appropriate target sequences, ideally present in all mycobacterial species (MTB complex) and absent in others. Methods. Amplification of three target sequences from unrelated genes, namely, hsp 65 (165 bp), dnaJ (365 bp), and insertion element IS 6110 (541 bp) by PCR was carried out in clinical samples from suspected cases of tuberculosis/ mycobacterioses and healthy controls. Results. The sensitivity of this method ranged from 73.33 to 84.61, and the specificity was 80. The PCR method was significantly better (P = 0.03 and P = 0.009) than both smear and culture methods. Conclusion. Our trimarker-based PCR method could specifically detect M. tuberculosis and MTB complex infection from that of major pathogenic NTM and nonpathogenic mycobacteria. This method, by well distinguishing between MTB complex and NTM, presented a fast and accurate method to detect and diagnose mycobacterial infections more efficiently and could thereby help in better patient management particularly considering the increase in mycobacterial infections due to emergence of NTM over the past decades. © 2012 Anamika Singh and Vijendra Kumar Kashyap. Source

Singh A.,National Analysis Center | Singh A.,Temple University | Gaughan J.P.,Temple University | Kashyap V.K.,National Analysis Center
International Journal of Tuberculosis and Lung Disease | Year: 2011

SETTING: Despite efforts at disease control, the incidence of tuberculosis (TB) remains high in India. OBJECTIVE: To assess the role of VDR and SLC11A1 gene polymorphisms in the development of pulmonary TB (PTB) in an ethnically matched population of India. DESIGN: In this case-control study, five variants (INT4/ rs3731865, 823C/T/rs17221959, D543N/rs17235409, 577G/A/rs1059823 and TGTG deletion-3′UTR/rs172 35416) of SLC11A1 and three (BsmI/rs1544410, FokI/ rs10735810 and TaqI/rs731236) of the VDR gene were studied in 101 TB patients and 225 controls from Kolkata, India. RESULTS: Statistically significant associations were observed for INT4: GC (OR 4.54 95%CI 2.38-8.68), CC (OR 35.20, 95%CI 9.15-135.38), 3′UTR (TGTG+/-, OR 2.96, 95%CI 1.52-5.78), TGTG-/- (OR 3.52, 95%CI 1.62-7.61) and 823C/T (CT, OR 0.31, 95%CI 0.17-0.58) variants of the SLC11A1 gene. Significantly different genotype frequencies between different groups of patients elucidated the role of the INT4 (P = 0.031), 577G/A (P = 0.033) and FokI (P = 0.02) variants in disease progression and the development of cavitary disease. Five haplotypes were also identified as having a significant association with PTB. CONCLUSION: This study, the first to include evidence on 577G/A and INT4, reports a significant association between SLC11A1 gene variants and PTB with respect to susceptibility and subsequent disease progression in East India. © 2011 The Union. Source

Meganathan P.R.,National Analysis Center | Dubey B.,National Analysis Center | Batzer M.A.,Louisiana State University | Ray D.A.,Louisiana State University | Haque I.,National Analysis Center
Molecular Phylogenetics and Evolution | Year: 2010

The genus Crocodylus consists of 11 species including the largest living reptile, Crocodylus porosus. The current understanding of the intrageneric relationships between the members of the genus Crocodylus is sparse. Even though members of this genus have been included in many phylogenetic analyses, different molecular approaches have resulted in incongruent trees leaving the phylogenetic relationships among the members of Crocodylus unresolved inclusive of the placement of C. porosus. In this study, the complete mitochondrial genome sequences along with the partial mitochondrial gene sequences and a nuclear gene, C-mos were utilized to infer the intrageneric relationships among Crocodylus species with a special emphasis on the phylogenetic position of C. porosus. Four different phylogenetic methods, Neighbour Joining, Maximum Parsimony, Maximum Likelihood and Bayesian inference, were utilized to reconstruct the crocodilian phylogeny. The uncorrected pairwise distances computed in the study, show close proximity of C. porosus to C. siamensis and the tree topologies thus obtained, also consistently substantiated this relationship with a high statistical support. In addition, the relationship between C. acutus and C. intermedius was retained in all the analyses. The results of the current phylogenetic study support the well established intergeneric crocodilian phylogenetic relationships. Thus, this study proposes the sister relationship between C. porosus and C. siamensis and also suggests the close relationship of C. acutus to C. intermedius within the genus Crocodylus. © 2010 Elsevier Inc. Source

Dubey B.,National Analysis Center | Dubey B.,Center for Cellular and Molecular Biology | Meganathan P.R.,National Analysis Center | Meganathan P.R.,Mississippi State University | Haque I.,National Analysis Center
Molecular Biology Reports | Year: 2012

This paper reports the complete mitochondrial genome sequence of an endangered Indian snake, Python molurus molurus (Indian Rock Python). A typical snake mitochondrial (mt) genome of 17258 bp length comprising of 37 genes including the 13 protein coding genes, 22 tRNA genes, and 2 ribosomal RNA genes along with duplicate control regions is described herein. The P. molurus molurus mt. genome is relatively similar to other snake mt. genomes with respect to gene arrangement, composition, tRNA structures and skews of AT/GC bases. The nucleotide com-positionof the genome shows that there are more A-C % than T-G% on the positive strand as revealed by positive AT and CG skews. Comparison of individual protein coding genes, with other snake genomes suggests that ATP8 and NADH3 genes have high divergence rates. Codon usage analysis reveals a preference of NNC codons over NNG codons in the mt. genome of P. molurus. Also, the synonymous and non- synonymous substitution rates (ka/ks) suggest that most of the protein coding genes are under purifying selection pressure. The phylogenetic analyses involving the concatenated 13 protein coding genes of P. molurus molurus conformed to the previously established snake phylogeny. © 2012 Springer Science+Business Media B.V. Source

Dubey B.,National Analysis Center | Meganathan P.R.,National Analysis Center | Haque I.,National Analysis Center
Journal of Forensic Sciences | Year: 2010

Three endangered Indian snake species, Python molurus, Naja naja, and Xenochrophis piscator are known to be significantly involved in illegal trade. Effective authentication of species is required to curb this illegal trade. In the absence of morphological features, molecular identification techniques hold promise to address the issue of species identification. We present an effective PCR-restriction fragment length polymorphism method for easy identification of the three endangered snake species, Python molurus, Naja naja, and Xenochrophis piscator. A 431-bp amplicon from cytochrome b gene was amplified using novel snake-specific primers following restriction digestion with enzymes Mbo II and Fok I. The species-specific reference fragment patterns were obtained for the target species, which enabled successful identification of even highly degraded shed skin sample confirming the utility of the technique in case of poor-quality DNA. The assay could be effectively used for forensic authentication of three Indian snake species and would help strengthen conservation efforts. © 2010 American Academy of Forensic Sciences. Source

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