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101.
Jyoti Kushwah Puneet Kumar Veena Garg Vishal Singh Somvanshi 《Indian journal of microbiology》2017,57(1):125-128
Photorhabdus is an insect-pathogenic Gram negative enterobacterium found in the gut of Heterorhabditis nematodes. Photorhabdus is highly virulent to insects, and can kill insects rapidly upon injection at very low concentrations of one to few cells. We characterized the virulence of Photorhabdus symbionts isolated from the Heterorhabditis nematodes collected from various parts of India by injecting different concentrations of bacterial cells into fourth instar larval stage of insect Galleria mellonella. Photorhabdus luminescens ssp. akhurstii strain IARI-SGMG3 from Meghalaya was identified as the most virulent of all the tested strains on the basis of LT50 and LC50 values. This study forms a basis for further investigations on the genetic basis of virulence in Photorhabdus bacteria. 相似文献
102.
Extraction of good-quality metagenomic DNA from extreme environments is quite challenging, particularly from high elevation hot spring sediments. Low microbial load, high humic acid content and other contaminants complicate the process of extraction of metagenomic DNA from hot spring sediments. In the present study, efficacy of five manual DNA extraction protocols with modifications has been evaluated for metagenomic DNA extraction from boron–sulfur rich high elevation Puga hot spring sediments. Best suited protocol was identified based on the cell lysis efficiency, DNA yield, humic acid content, PCR reproducibility and representation of bacterial diversity. Quantity as well as quality of crude metagenomic DNA differed remarkably between various protocols used and were not pure enough to give PCR amplification using 16S rRNA bacterial and archaeal primers. Crude metagenomic DNA extracted using five different DNA extraction protocols was purified using spin column based purification method. Even after purification, only three protocols C, D and E yielded metagenomic DNA that could be amplified using both archaeal and bacterial primers. To evaluate the degree of microbial diversity represented by protocols C, D and E, phylogenetic genes amplified were subjected to amplified ribosomal DNA restriction analysis (ARDRA) and denaturing gradient gel electrophoresis analysis (DGGE) analysis. ARDRA banding pattern of amplicons generated for all the three extraction protocols, i.e., C, D and E were found to be similar. DGGE of protocol E derived amplicons resulted in the similar number of dominant bands but a greater number of non-dominant bands, i.e., the highest microbial diversity in comparison to protocols C and D, respectively. In the present study, protocol E developed from Yeates et al. protocol has been found to be best in terms of DNA yield, DNA purity and bacterial diversity depiction associated with boron–sulfur rich sediment of high elevation hot springs. 相似文献
103.
Debleena Guin Manish Kumar Mishra Puneet Talwar Chitra Rawat Suman S. Kushwaha Shrikant Kukreti Ritushree Kukreti 《BMC medical genomics》2017,10(1):56
Background
PD is a progressive neurodegenerative disorder commonly treated by levodopa. The findings from genetic studies on adverse effects (ADRs) and levodopa efficacy are mostly inconclusive. Here, we aim to identify predictive genetic biomarkers for levodopa response (LR) and determine common molecular link with disease susceptibility. A systematic review for LR was conducted for ADR, and drug efficacy, independently. All included articles were assessed for methodological quality on 14 parameters. GWAS of PD were also reviewed. Protein-protein interaction (PPI) analysis using STRING and functional enrichment using WebGestalt was performed to explore the common link between LR and PD.Results
From 37 candidate studies on levodopa toxicity, 18 genes were found associated, of which, CAn STR 13, 14 (DRD2) was most significantly associated with dyskinesia, followed by rs1801133 (MTHFR) with hyper-homocysteinemia, and rs474559 (HOMER1) with hallucination. Similarly, 8 studies on efficacy resulted in 4 genes in which rs28363170, rs3836790 (SLC6A3) and rs4680 (COMT), were significant. To establish the molecular connection between LR with PD, we identified 35 genes significantly associated with PD. With 19 proteins associated with LR and 35 with PD, two independent PPI networks were constructed. Among the 67 nodes (263 edges) in LR, and 62 nodes (190 edges) in PD pathophysiology, UBC, SNCA, FYN, SRC, CAMK2A, and SLC6A3 were identified as common potential candidates.Conclusion
Our study revealed the genetically significant polymorphism concerning the ADRs and levodopa efficacy. The six common genes may be used as predictive markers for therapy optimization and as putative drug target candidates.104.
105.
Xenorhabdus nematophila produces type 1 fimbriae on the surface of Phase I cells. Fimbriae mediate recognition and adhesion of the bacteria to its target cell. To investigate the role of fimbriae in the biology of X. nematophila , we have produced a fimbrial mutant strain by insertional inactivation of the mrx A gene, encoding the structural subunit of type 1 fimbriae. Phenotypic characterization of the mutant revealed loss of fimbriae on the cell surface. Cell surface characteristics like dye absorption, biofilm formation, red blood cell agglutination remained unaltered. The mrx A mutant was defective in swarming on soft agar, although swimming motility was not affected. Flagellar expression was suppressed in the mrxA strain under swarming conditions, but not swimming conditions. Agglutination and cytotoxicity of the mutant to larval haemocytes was also reduced. When the mutant cells were injected in the haemocoel of the fourth instar larvae of Helicoverpa armigera , an increase in the LT50 of 9–12 h was observed relative to the wild-type strain. The nematode growth was slow on the lawn of the fimbrial mutant. The mrxA negative strain was unable to colonize the nematode gut efficiently. This study demonstrates importance of type 1 fimbriae in establishment of bacteria-nematode symbiosis, a key to successful pest management program. 相似文献
106.
107.
Epithelial cells respond to mechanical stimuli by increasing exocytosis, endocytosis, and ion transport, but how these processes are initiated and coordinated and the mechanotransduction pathways involved are not well understood. We observed that in response to a dynamic mechanical environment, increased apical membrane tension, but not pressure, stimulated apical membrane exocytosis and ion transport in bladder umbrella cells. The exocytic response was independent of temperature but required the cytoskeleton and the activity of a nonselective cation channel and the epithelial sodium channel. The subsequent increase in basolateral membrane tension had the opposite effect and triggered the compensatory endocytosis of added apical membrane, which was modulated by opening of basolateral K+ channels. Our results indicate that during the dynamic processes of bladder filling and voiding apical membrane dynamics depend on sequential and coordinated mechanotransduction events at both membrane domains of the umbrella cell. 相似文献
108.
Andrew C. Bishop Beth A. Surlow Puneet Anand Katherine Hofer Matthew Henkel Jana Patton-Vogt 《Eukaryotic cell》2009,8(11):1808-1811
Saccharomyces cerevisiae produces extracellular glycerophosphoinositol through phospholipase-mediated turnover of phosphatidylinositol and transports glycerophosphoinositol into the cell upon nutrient limitation. A screening identified the RAS GTPase-activating proteins Ira1 and Ira2 as required for utilization of glycerophosphoinositol as the sole phosphate source, but the RAS/cyclic AMP pathway does not appear to be involved in the growth phenotype. Ira1 and Ira2 affect both the production and transport of glycerophosphoinositol.Membrane phospholipids are continually synthesized and degraded as cells grow and respond to environmental conditions. A major pathway of phosphatidylinositol (PI) turnover in Saccharomyces cerevisiae is its deacylation to produce extracellular glycerophosphoinositol (GroPIns) (3). Plb3, an enzyme with phospholipase B (PLB)/lysophospholipase activity, is thought to be primarily responsible for the production of extracellular GroPIns, with Plb1 playing a lesser role (11, 12, 13). GroPIns is transported into the cell by the Git1 permease (17). GIT1 expression is upregulated by phosphate limitation and inositol limitation. In fact, GroPIns can act as the cell''s sole source of both inositol (17) and phosphate (1).A screening for gene products involved in the process by which GroPIns enters the cellular metabolism identified Ira1 and Ira2, yeast homologs of the mammalian protein neurofibromin. Alterations in NF1, the gene encoding neurofibromin, are associated with the pathogenesis of neurofibromatosis type 1, an autosomal dominant genetic disease (4, 5, 25). Ira1 and Ira2 and neurofibromin function as RAS GTPase-activating proteins (RAS GAPs). S. cerevisiae Ras1 and Ras2 activate adenylate cyclase to modulate cyclic AMP (cAMP) levels. The binding of cAMP to the regulatory subunits of protein kinase A (Bcy1) results in dissociation and activation of the catalytic subunits (Tpk1 to Tpk3). Ira1 and Ira2 inactivate RAS and thereby downregulate the pathway (18, 19). Hydrolysis of cAMP by the phosphodiesterases encoded by PDE1 and PDE2 also downregulate the pathway (7, 20, 23). The RAS/cAMP pathway responds to nutrient signals to modulate fundamental cellular processes, including stress resistance, metabolism, and cell proliferation (7, 20, 21). 相似文献
109.
Beena E. Thomas Puneet K. Dewan Sophia Vijay Aleyamma Thomas Lakhdir Singh Chauhan Chandrasekaran Vedachalam Preetish Vaidyanathan Soumya Swaminathan 《PloS one》2009,4(12)
Background
The acceptability and feasibility of provider-initiated HIV testing and counseling (PITC) in many settings across Asia with concentrated HIV epidemics is not known. A pilot study of the PITC policy undertaken within the public health care systems in two districts in India offered the opportunity to understand patient''s perspectives on the process of referral for HIV testing and linking to HIV treatment and care.Methods
We conducted a cross-sectional study of randomly selected TB patients registered by the TB control program between July and November 2007 in two districts in south India. Trained interviewers met patients shortly after TB diagnosis and administered a structured questionnaire. Patients were assessed regarding their experience with HIV status assessment, referral for counseling and testing, and for HIV-infected patients the counseling itself and subsequent referral for HIV treatment and care.Results
Of the 568 interviewed TB patients, 455 (80%) reported being referred for HIV testing after they presented to the health facility for investigations or treatment for TB. Over half the respondents reported having to travel long distances and incurred financial difficulties in reaching the Integrated Counselling and Testing Centre (ICTC) and two-thirds had to make more than two visits. Only 48% reported having been counseled before the test. Of the 110 HIV-infected patients interviewed, (including 43 with previously-known positive HIV status and 67 detected by PITC), 89 (81%) reported being referred for anti-retroviral treatment (ART); 82 patients reached the ART centre but only 44 had been initiated on ART.Conclusions
This study provides the first evidence from India that routine, provider-initiated voluntary HIV testing of TB patients is acceptable, feasible and can be achieved with very high efficiency under programmatic conditions. While PITC is useful in identifying new HIV-infected patients so that they can be successfully linked to ART, the convenience and proximity of testing centres, quality of HIV counseling, and efficiency of ART services need attention. 相似文献110.
Sophia Vijay Soumya Swaminathan Preetish Vaidyanathan Aleyamma Thomas L. S. Chauhan Prahlad Kumar Sonali Chiddarwar Beena Thomas Puneet K. Dewan 《PloS one》2009,4(11)