273 results on '"Chandrashekhar, K."'
Search Results
252. Genome Sequence of Citrobacter freundii AMC0703, Isolated from the Intestinal Lumen of an 11-Year-Old Organ Donor.
- Author
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Marsh AJ, Chandrashekhar K, Ng S, Roach J, Magness ST, and Azcarate-Peril MA
- Abstract
Citrobacter freundii AMC0703 was isolated from the intestinal mucosa of an 11-year-old organ donor. Genome analysis revealed the presence of multiple factors potentially aiding in pathogenicity, including fimbriae, flagella, and genes encoding resistance to fluoroquinolones, cephamycin, fosfomycin, and aminocoumarin., (Copyright © 2020 Marsh et al.)
- Published
- 2020
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253. Lumen and mucosa-associated Lactobacillus rhamnosus from the intestinal tract of organ donors.
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Marsh AJ, Yaya AA, Ng S, Chandrashekhar K, Roach J, Magness ST, and Azcarate-Peril MA
- Abstract
Knowledge of the intra-individual spatial and regional distribution of intestinal microbial populations is essential to understand gut host-microbial interactions. In this study, we performed a compositional analysis of luminal and mucosal samples from the small and large intestine of four organ donors by 16S rRNA amplicon sequencing and high-throughput quantitative polymerase chain reaction. Since the human microbiota is subject to selection pressure at lower taxonomic levels, we isolated over 400 bacterial strains and investigated strain-level variation of 11 Lactobacillus rhamnosus from different intestinal regions. Results substantiate reported inter-individual variability as well as intra-individual differences along the gastrointestinal tract. Although the luminal and mucosal-associated communities were similar within individuals, relative abundance reflected the donors' demographic and potential pathologies. The total bacterial load of all donors increased from small intestine to colon, while Bifidobacterium was in greater abundance in the small intestine. Comparative genomic analysis of L. rhamnosus showed the strains segregated into two distinct clusters and identified no features specific to location. Analysis revealed genetic differences for exopolysaccharide production, carbohydrate utilization, pilus formation and vitamin K biosynthesis between clusters. This study contributes to the understanding of niche-specific microbial communities, encouraging subsequent studies to better understand microbial signatures at lower taxonomic levels., (© The Author(s) 2020.)
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- 2020
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254. Self-blood pressure measurement as compared to office blood pressure measurement in a large Indian population; the India Heart Study.
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Kaul U, Wander GS, Sinha N, Mohan JC, Kumar S, Dani S, Ponde CK, Pinto B, Dalal J, Hiremath J, Kapoor S, Baruah DK, Nair T, Alexander T, Mohan V, Joshi S, Sivakadaksham N, Omboni S, Arambam P, Suvarna V, and Verberk WJ
- Subjects
- Adult, Female, Humans, Hypertension physiopathology, India epidemiology, Male, Masked Hypertension diagnosis, Middle Aged, Office Visits, Oscillometry, Prevalence, Primary Health Care, Reproducibility of Results, White Coat Hypertension diagnosis, Blood Pressure, Blood Pressure Determination methods, Hypertension diagnosis, Self Care
- Abstract
Objective: India Heart Study (IHS) is aimed at investigating the agreement between office blood pressure measurement (OBPM) and self (S)BPM in a hypertension-naive population., Methods: A total of 18 918 individuals (aged 42.6 ± 11.7 years, 62.7% men), visiting 1237 primary care physicians across India, underwent OBPM. They performed SBPM for a period of 1 week using a validated oscillometric BP monitor that was preprogrammed to adhere to a guideline-based SBPM-schedule and blinded to the results. Thereafter, individuals underwent a second OBPM. Available laboratory results were obtained. Thresholds for elevated OBPM and SBPM were 140/90 and 135/85 mmHg, respectively., Results: On the basis of first-visit OBPM and SBPM, there were 5787 (30.6%) individuals with normotension; 5208 (27.5%) with hypertension; 4485 (23.7%) with white-coat hypertension (WCH) and 3438 (18.2%) with masked hypertension. Thus, a diagnosis contradiction between SBPM and first-visit OBPM was seen in 9870 (41.9%) individuals. On the basis of second-visit OBPM, the normotension, hypertension, WCH and masked hypertension prevalence values were 7875 (41.6%); 4857 (25.7%); 2397 (12.7%) and 3789 (20.0%). There was poor agreement (kappa value 0.37) between OBPM of visit 1 and 2 with a diagnosis difference in 6027 (31.8%) individuals. The majority of masked hypertension and WCH individuals had BP values close to thresholds., Conclusion: There was a poor agreement between OBPM of visit1 and visit 2. Likewise, the agreement between OBPM at both visits and SBPM was poor. SBPM being considered to have a better correlation with patient prognosis should be the preferred method for diagnosing hypertension.
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- 2020
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255. Silent Brain Infarcts in Patients with Non Specific Neurological Symptoms.
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Junjappanavar AS and Chandrashekhar KV
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- Humans, Risk Factors, Brain Infarction diagnostic imaging, Magnetic Resonance Imaging
- Published
- 2020
256. Association between Gut Microbiome Composition and Rotavirus Vaccine Response among Nicaraguan Infants.
- Author
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Fix J, Chandrashekhar K, Perez J, Bucardo F, Hudgens MG, Yuan L, Twitchell E, Azcarate-Peril MA, Vilchez S, and Becker-Dreps S
- Subjects
- Bacteria classification, Feces microbiology, Female, Humans, Infant, Male, Nicaragua epidemiology, Seroconversion, Gastrointestinal Microbiome, Rotavirus Infections prevention & control, Rotavirus Vaccines immunology
- Abstract
Rotavirus is the leading cause of childhood deaths due to diarrhea. Although existing oral rotavirus vaccines are highly efficacious in high-income countries, these vaccines have been demonstrated to have decreased efficacy in low- and middle-income countries. A possible explanation for decreased efficacy is the impact of gut microbiota on the enteric immune system's response to vaccination. We analyzed the gut microbiome of 50 children enrolled in a prospective study evaluating response to oral pentavalent rotavirus vaccination (RV5) to assess associations between relative abundance of bacterial taxa and seroconversion following vaccination. Stool samples were taken before the first RV5 dose, and microbiome composition characterized using 16S rRNA amplicon sequencing and Quantitative Insights Into Microbial Ecology software. Relative abundance of bacterial taxa between seroconverters following the first RV5 dose, those with ≥ 4-fold increase in rotavirus-specific IgA titers, and nonseroconverters were compared using the Wilcoxon-Mann-Whitney test. We identified no significant differences in microbiome composition between infants who did and did not respond to vaccination. Infants who responded to vaccination tended to have higher abundance of Proteobacteria and Eggerthella , whereas those who did not respond had higher abundance of Fusobacteria and Enterobacteriaceae; however, these differences were not statistically significant following a multiple comparison correction. This study suggests a limited impact of gut microbial taxa on response to oral rotavirus vaccination among infants; however, additional research is needed to improve our understanding of the impact of gut microbiome on vaccine response, toward a goal of improving vaccine efficacy and rotavirus prevention.
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- 2020
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257. Differential methylation pattern in patients with coronary artery disease: pilot study.
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Banerjee S, Ponde CK, Rajani RM, and Ashavaid TF
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- Adult, CpG Islands genetics, Epigenesis, Genetic genetics, Epigenomics, Gene Ontology, Genome, Human genetics, Genome-Wide Association Study, HLA Antigens genetics, HLA-DQ alpha-Chains genetics, HLA-DQ beta-Chains genetics, HLA-DRB1 Chains genetics, Humans, India, Male, Middle Aged, Pilot Projects, Transcriptome genetics, Coronary Artery Disease genetics, DNA Methylation genetics
- Abstract
Epidemiological studies have revealed that coronary artery disease (CAD) is highly heritable. However, genetic studies have not been able to fully elucidate its etiology. Accumulating evidences suggest that epigenetic alterations like DNA methylation may provide an alternative and additional explanation of its pathophysiology. DNA methylation regulates hypomethylation and hypermethylation of various genes which are involved in the development of CAD. Our aim was to identify differentially methylated regions (DMRs) in genome of CAD patients by using the microarray chip having a coverage of > 4,50,000 CpG sites (Illumina's Infinium HumanMethylation450 BeadChip). In this pilot study, an epigenome-wide analysis of DNA methylation from whole blood was performed in six angiographically positive male cases, who were age and gender matched with six angiographically negative controls. All subjects were non-smokers, non-diabetic, non-alcoholic, with no previous history of cardiac ailment. Illumina's GenomeStudio (v 2011.1) software was used to identify DMRs and pathway analysis, gene ontology was carried out using DAVID (Database for Annotation, Visualisation and Integrated Discovery). 429 DMRs were found to be significant of which 222 were hypomethylated and 207 were hypermethylated. Antigen processing and presentation was identified to be the most significant biological function with a statistical significance of p = 4.35 × 10
- 5 . HLA-DRB1, HLA-DQA1, HLA-DQB1 along with non-classical HLA molecules HLA-G, HLA-C are responsible for triggering the inflammatory pathway which have been identified in our study. To the best of our knowledge, this is the first study to identify a panel of DMRs using a high coverage microarray chip in India.- Published
- 2019
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258. Transducer-Like Protein in Campylobacter jejuni With a Role in Mediating Chemotaxis to Iron and Phosphate.
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Chandrashekhar K, Srivastava V, Hwang S, Jeon B, Ryu S, and Rajashekara G
- Abstract
Chemotaxis-mediated motility enables Campylobacter jejuni to navigate through complex environmental gradients and colonize diverse niches. C. jejuni is known to possess several methyl accepting chemotaxis proteins (MCPs), also called transducer-like proteins (Tlps). While the role of some of the Tlps in chemotaxis has been identified, their regulation and role in virulence is still not very clear. Here, we investigated the contribution of Tlp2 to C. jejuni chemotaxis, stress survival and colonization of the chicken gastrointestinal tract. The Δ tlp2 deletion mutant showed decreased chemotaxis toward aspartate, pyruvate, inorganic phosphate (Pi), and iron (FeSO
4 ). Transcriptional analysis of tlp2 with a promoter fusion reporter assay revealed that the tlp2 promoter (Ptlp2 ) was induced by Pi and iron, both in the ferrous (Fe2+ ) and ferric form (Fe3+ ). RT-PCR analysis using overlapping primers indicated that the phoX gene, located immediately downstream of tlp2, is co-transcribed with tlp2 . A transcription start site was identified at 53 bp upstream of the tlp2 start codon. The Δ tlp2 mutant showed decreased colonization of the chicken gastrointestinal tract. Collectively, our findings revealed that the tlp2 plays a role in C. jejuni pathogenesis and colonization in the chicken host and its expression is regulated by iron.- Published
- 2018
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259. Functional outcome of an early anterior cruciate ligament reconstruction in comparison to delayed: Are we waiting in vain?
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Manandhar RR, Chandrashekhar K, Kumaraswamy V, Sahanand S, and Rajan D
- Abstract
Background: Surgical techniques of ACL reconstruction (ACLR) have evolved over the past three decades along with debate regarding timing of reconstruction. It was a widespread belief that the timing of surgery was an important factor in determining the resulting stiffness after ACLR. Delayed rather than early reconstruction of the ACL is the current recommended treatment since it is thought to give a better functional outcome. However, there is no consensus in the literature regarding the optimal time of surgical intervention. The purpose of this study was to compare the range of motion and functional outcome in patients who underwent ACLR early with those that were delayed., Materials and Methods: The patients were randomized into two groups; patients who underwent the procedure within three weeks were kept in Group I (Early) and those patients who were reconstructed after six weeks were categorized as Group II (Delayed). Hamstring grafts were used and a standard protocol of surgery and physiotherapy was followed. The range of motion, IKDC and Tegner scores were compared., Results: A hundred and four patients underwent ACLR; fifty-three patients were grouped as Group I (Early) and fifty one as Group II (Delayed). The range of motion of both groups was comparable. The IKDC and Tegner scores were also comparable for early (Group I) ACLR and the patients who had their ACL reconstructed after a delay of at least 6 weeks (Group II)., Conclusion: There are no clinical differences in terms of range of motion and functional results between early and delayed ACLR.
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- 2018
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260. Campylobacter jejuni transducer like proteins: Chemotaxis and beyond.
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Chandrashekhar K, Kassem II, and Rajashekara G
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- Animals, Bacterial Proteins genetics, Campylobacter Infections microbiology, Campylobacter jejuni genetics, Chickens, Gastrointestinal Tract microbiology, Bacterial Proteins metabolism, Campylobacter Infections veterinary, Campylobacter jejuni physiology, Chemotaxis
- Abstract
Chemotaxis, a process that mediates directional motility toward or away from chemical stimuli (chemoeffectors/ligands that can be attractants or repellents) in the environment, plays an important role in the adaptation of Campylobacter jejuni to disparate niches. The chemotaxis system consists of core signal transduction proteins and methyl-accepting-domain-containing Transducer like proteins (Tlps). Ligands binding to Tlps relay a signal to chemotaxis proteins in the cytoplasm which initiate a signal transduction cascade, culminating into a directional flagellar movement. Tlps facilitate substrate-specific chemotaxis in C. jejuni, which plays an important role in the pathogen's adaptation, pathobiology and colonization of the chicken gastrointestinal tract. However, the role of Tlps in C. jejuni's host tissue specific colonization, physiology and virulence remains not completely understood. Based on recent studies, it can be predicted that Tlps might be important targets for developing strategies to control C. jejuni via vaccines and antimicrobials.
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- 2017
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261. Troponin T and Heart Type Fatty Acid Binding Protein (h-Fabp) as Biomarkers in Patients Presenting with Chest Pain.
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Reddy LL, Shah SA, Dherai AJ, Ponde CK, and Ashavaid TF
- Abstract
Acute coronary syndrome (ACS) is a term for a range of clinical signs and symptoms suggestive of myocardial ischemia. It results in functional and structural changes and ultimately releasing protein from injured cardiomyocytes. These cardiac markers play a major role in diagnosis and prognosis of ACS. This study aims to assess the efficacy of heart type fatty acid binding protein (h-FABP) as a marker for ACS along with the routinely used hs-TropT. In our observational study, plasma h-FABP (cut-off 6.32 ng/ml) and routinely done hs-Trop T (cutoff 0.1 and 0.014 ng/ml) were estimated by immunometric laboratory assays in 88 patients with acute chest pain. Based on the clinical and laboratory test findings the patients were grouped into ACS (n = 41) and non-ACS (n = 47). The diagnostic sensitivity, specificity, NPV, PPV and ROC curve at 95 % CI were determined. Sensitivity of hs-TropT (0.1 ng/ml), hs-TropT (0.014 ng/ml) and h-FABP were 53, 86 and 78 % respectively and specificity for the same were 98, 73 and 70 % respectively. Sensitivity, specificity and NPV calculated for a cut-off combination of hs-TropT 0.014 ng/ml and h-FABP was 100, 51 and 100 % respectively. These results were substantiated by ROC analysis. Measurement of plasma h-FABP and hs-TropT together on admission appears to be more precise predictor of ACS rather than either hs-Trop T or h-FABP.
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- 2016
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262. Limit of detection of genomic DNA by conventional PCR for estimating the load of Staphylococcus aureus and Escherichia coli associated with bovine mastitis.
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Chandrashekhar KM, Isloor S, Veeresh BH, Hegde R, Rathnamma D, Murag S, Veeregowda BM, Upendra HA, and Hegde NR
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- Animals, Bacterial Proteins genetics, Cattle, Escherichia coli genetics, Escherichia coli Infections diagnosis, Escherichia coli Infections microbiology, Female, Limit of Detection, Mastitis, Bovine diagnosis, Staphylococcal Infections diagnosis, Staphylococcal Infections microbiology, Staphylococcus aureus genetics, DNA, Bacterial genetics, Escherichia coli isolation & purification, Escherichia coli Infections veterinary, Mastitis, Bovine microbiology, Polymerase Chain Reaction methods, Staphylococcal Infections veterinary, Staphylococcus aureus isolation & purification
- Abstract
Detection of mastitis-associated bacteria can be accomplished by culturing or by molecular techniques. On the other hand, rapid and inexpensive methods to enumerate bacterial load without culturing can be better achieved by molecular methods. Staphylococcus aureus and Escherichia coli are the predominant bacterial pathogens associated with bovine mastitis. Here, we describe the application of conventional PCR for the limit of detection (LOD) of genomic DNA of S. aureus and E. coli based on single-copy genes. The selected genes were thermonuclease (nuc), aureolysin (aur), and staphopain A (scpA) for S. aureus and β-D-glucuronidase A (uidA), cytochrome d oxidase (cyd), and rodA (a gene affecting cell shape and methicillin sensitivity) for E. coli. The LOD was 5.3, 15.9, and 143 pg for aur, nuc, and scpA genes, corresponding to S. aureus genomic copies of 1.75 × 10(3), 5.16 × 10(3), and 4.71 × 10(4), respectively. The LOD was 0.45, 12.3 and 109 pg for uidA, rodA and cyd genes, corresponding to E. coli genome copies of 8.91 × 10(1), 2.43 × 10(3), and 2.16 × 10(4), respectively. Application of uidA and aur PCRs to field strains revealed that as low as approximately 100 genome copies of E. coli and 1000-10,000 copies of S. aureus could be detected. This study is the first to report LOD of genomic DNA using conventional PCR for aur and scpA genes of S. aureus, and rodA and cyd genes of E. coli. The results should be useful for developing assays to assess bacterial load in milk and to determine the load that contributes to subclinical or clinical mastitis.
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- 2015
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263. Transducer like proteins of Campylobacter jejuni 81-176: role in chemotaxis and colonization of the chicken gastrointestinal tract.
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Chandrashekhar K, Gangaiah D, Pina-Mimbela R, Kassem II, Jeon BH, and Rajashekara G
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- Animals, Bacterial Adhesion, Bacterial Proteins genetics, Biofilms growth & development, Campylobacter Infections microbiology, Campylobacter jejuni genetics, Campylobacter jejuni growth & development, Campylobacter jejuni metabolism, Cells, Cultured, Chickens, Endocytosis, Epithelial Cells microbiology, Gene Deletion, Humans, Locomotion, Membrane Proteins genetics, Methyl-Accepting Chemotaxis Proteins, Virulence Factors genetics, Bacterial Proteins metabolism, Campylobacter Infections veterinary, Campylobacter jejuni physiology, Chemotaxis, Gastrointestinal Tract microbiology, Membrane Proteins metabolism, Virulence Factors metabolism
- Abstract
Transducer Like Proteins (Tlps), also known as methyl accepting chemotaxis proteins (MCP), enable enteric pathogens to respond to changing nutrient levels in the environment by mediating taxis toward or away from specific chemoeffector molecules. Despite recent advances in the characterization of chemotaxis responses in Campylobacter jejuni, the impact of Tlps on the adaptation of this pathogen to disparate niches and hosts is not fully characterized. The latter is particularly evident in the case of C. jejuni 81-176, a strain that is known to be highly invasive. Furthermore, the cytoplasmic group C Tlps (Tlp5, 6, and 8) were not extensively evaluated. Here, we investigated the role of C. jejuni 81-176 Tlps in chemotaxis toward various substrates, biofilm formation, in vitro interaction with human intestinal cells, and chicken colonization. We found that the Δtlp6 and Δtlp10 mutants exhibited decreased chemotaxis toward aspartate, whereas the Δtlp6 mutant displayed a decreased chemotaxis toward Tri-Carboxylic Acid (TCA) cycle intermediates such as pyruvate, isocitrate, and succinate. Our findings also corroborated that more than one Tlp is involved in mediating chemotaxis toward the same nutrient. The deletion of tlps affected important phenotypes such as motility, biofilm formation, and invasion of human intestinal epithelial cells (INT-407). The Δtlp8 mutant displayed increased motility in soft agar and showed decreased biofilm formation. The Δtlp8 and Δtlp9 mutants were significantly defective in invasion in INT-407 cells. The Δtlp10 mutant was defective in colonization of the chicken proximal and distal gastrointestinal tract, while the Δtlp6 and Δtlp8 mutants showed reduced colonization of the duodenum and jejunum. Our results highlight the importance of Tlps in C. jejuni's adaptation and pathobiology.
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- 2015
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264. Transcriptome analysis of Campylobacter jejuni polyphosphate kinase (ppk1 and ppk2) mutants.
- Author
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Chandrashekhar K, Kassem II, Nislow C, Gangaiah D, Candelero-Rueda RA, and Rajashekara G
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- Base Sequence, Gene Expression, Molecular Sequence Data, Mutation, Sequence Analysis, RNA, Campylobacter jejuni enzymology, Campylobacter jejuni genetics, Gene Expression Profiling, Phosphotransferases (Phosphate Group Acceptor) genetics
- Published
- 2015
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265. Polyphosphate-mediated modulation of Campylobacter jejuni biofilm growth and stability.
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Drozd M, Chandrashekhar K, and Rajashekara G
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- Campylobacter jejuni drug effects, Campylobacter jejuni growth & development, Campylobacter jejuni metabolism, Gene Deletion, Gene Expression Profiling, Gene Expression Regulation, Bacterial, Biofilms drug effects, Biofilms growth & development, Campylobacter jejuni physiology, Polyphosphates metabolism
- Abstract
Biofilms increase C. jejuni's resilience to detergents, antibiotics, and environmental stressors. In these investigations, we studied the modulation of biofilm in response to phosphate related stressors. We found that the deletion of ppk1, phoX, and ppk2 (polyphosphate associated [poly P] genes) in C. jejuni modulated different stages of biofilm formation such as attached microcolonies, air-liquid biofilms, and biofilm shedding. Additionally, inorganic phosphate also modulated attached microcolonies, air-liquid biofilms, and biofilm shedding both independently of and additively in the poly P associated mutants. Furthermore, we observed that these different biofilm stages were affected by biofilm age: for example, the adherent microcolonies were maximum on day 2, while biofilm growth at the air-liquid interface and shedding was highest on day 3. Also, we observed altered calcofluor white reactive polysaccharides in poly P-associated mutants, as well as increased secretion of autoinducer-2 (AI-2) quorum sensing molecules in the ∆ppk2 mutant. Further, the polysaccharide and flagellar biosynthesis genes, that are associated with biofilm formation, were altered in these poly P-associated mutants. We conclude that the phosphate limiting condition modulates C. jejuni biofilm formation.
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- 2014
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266. WsSGTL1 gene from Withania somnifera, modulates glycosylation profile, antioxidant system and confers biotic and salt stress tolerance in transgenic tobacco.
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Pandey V, Niranjan A, Atri N, Chandrashekhar K, Mishra MK, Trivedi PK, and Misra P
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- Adaptor Proteins, Signal Transducing, Animals, Biological Assay, Chlorophyll metabolism, Feeding Behavior, Fluorescence, Glycosylation, Plant Leaves, Plants, Genetically Modified, Rutin, Sodium Chloride pharmacology, Spodoptera, Stress, Physiological, Nicotiana drug effects, Nicotiana physiology, Withania metabolism, Antioxidants metabolism, Gene Expression Regulation, Plant physiology, Salt-Tolerant Plants genetics, Nicotiana genetics, Transcriptome, Withania genetics
- Abstract
Glycosylation of sterols, catalysed by sterol glycosyltransferases (SGTs), improves the sterol solubility, chemical stability and compartmentalization, and helps plants to adapt to environmental changes. The SGTs in medicinal plants are of particular interest for their role in the biosynthesis of pharmacologically active substances. WsSGTL1, a SGT isolated from Withania somnifera, was expressed and functionally characterized in transgenic tobacco plants. Transgenic WsSGTL1-Nt lines showed an adaptive mechanism through demonstrating late germination, stunted growth, yellowish-green leaves and enhanced antioxidant system. The reduced chlorophyll content and chlorophyll fluorescence with decreased photosynthetic parameters were observed in WsSGTL1-Nt plants. These changes could be due to the enhanced glycosylation by WsSGTL1, as no modulation in chlorophyll biogenesis-related genes was observed in transgenic lines as compared to wildtype (WT) plants. Enhanced accumulation of main sterols like, campesterol, stigmasterol and sitosterol in glycosylated form was observed in WsSGTL1-Nt plants. Apart from these, other secondary metabolites related to plant's antioxidant system along with activities of antioxidant enzymes (SOD, CAT; two to fourfold) were enhanced in WsSGTL1-Nt as compared to WT. WsSGTL1-Nt plants showed significant resistance towards Spodoptera litura (biotic stress) with up to 27 % reduced larval weight as well as salt stress (abiotic stress) with improved survival capacity of leaf discs. The present study demonstrates that higher glycosylation of sterols and enhanced antioxidant system caused by expression of WsSGTL1 gene confers specific functions in plants to adapt under different environmental challenges.
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- 2014
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267. Functional characterization of exopolyphosphatase/guanosine pentaphosphate phosphohydrolase (PPX/GPPA) of Campylobacter jejuni.
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Malde A, Gangaiah D, Chandrashekhar K, Pina-Mimbela R, Torrelles JB, and Rajashekara G
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- Acid Anhydride Hydrolases genetics, Bacterial Proteins genetics, Biofilms, Campylobacter Infections immunology, Campylobacter jejuni genetics, Campylobacter jejuni physiology, Cell Line, Complement System Proteins immunology, Humans, Pyrophosphatases genetics, Acid Anhydride Hydrolases metabolism, Bacterial Proteins metabolism, Campylobacter Infections microbiology, Campylobacter jejuni enzymology, Pyrophosphatases metabolism
- Abstract
The inorganic polyphosphate (poly-P) is a key regulator of stress responses and virulence in many bacterial pathogens including Campylobacter jejuni. The role of exopolyphosphatases/guanosine pentaphosphate (pppGpp) phosphohydrolases (PPX/GPPA) in poly-P homeostasis and C. jejuni pathobiology remains unexplored. Here, we analyzed deletion mutants (∆ppx1, ∆ppx2) and the double knockout mutant (dkppx), all ∆ppx mutants exhibited increased capacity to accumulate poly-P; however only ∆ppx1 and dkppx mutants showed decreased accumulation of ppGpp, an alarmone molecule that regulates stringent response in bacteria, suggesting potential dual role for PPX1/GPPA. Nutrient survival defect of ∆ppx mutants was rescued by the supplementation of specific amino acids implying that survival defect may be associated with decreased ppGpp and/ or increased poly-P in ∆ppx mutants. The ppk1 and spoT were upregulated in both ∆ppx1 and ∆ppx2 suggesting a compensatory role for SpoT and Ppk1 in poly-P and ppGpp homeostasis. The lack of ppx genes resulted in defects in motility, biofilm formation, nutrient stress survival, invasion and intracellular survival indicating that maintaining a certain level of poly-P is critical for ppx genes in C. jejuni pathophysiology. Both ppx1 and ppx2 mutants were resistant to human complement-mediated killing; however, the dkppx mutant was sensitive. The serum susceptibility did not occur in the presence of MgCl 2 and EGTA suggesting an involvement of the classical or lectin pathway of complement mediated killing. Interestingly, the chicken serum did not have any effect on the ∆ppx mutants' survival. The observed serum susceptibility was not related to C. jejuni surface capsule and lipooligosaccharide structures. Our study underscores the importance of PPX/GPPA proteins in poly-P and ppGpp homeostasis, two critical molecules that modulate environmental stress responses and virulence in C. jejuni.
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- 2014
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268. Of energy and survival incognito: a relationship between viable but non-culturable cells formation and inorganic polyphosphate and formate metabolism in Campylobacter jejuni.
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Kassem II, Chandrashekhar K, and Rajashekara G
- Abstract
Campylobacter jejuni is a Gram-negative food-borne bacterium that can cause mild to serious diseases in humans. A variety of stress conditions including exposure to formic acid, a weak organic acid, can cause C. jejuni to form viable but non-culturable cells (VBNC), which was proposed as a potential survival mechanism. The inability to detect C. jejuni VBNC using standard culturing techniques may increase the risk of exposure to foods contaminated with this pathogen. However, little is known about the cellular mechanisms and triggers governing VBNC formation. Here, we discuss novel mechanisms that potentially affect VBNC formation in C. jejuni and emphasize the impact of formic acid on this process. Specifically, we highlight findings that show that impairing inorganic polyphosphate (poly-P) metabolism reduces the ability of C. jejuni to form VBNC in a medium containing formic acid. We also discuss the potential effect of poly-P and formate metabolism on energy homeostasis and cognate VBNC formation. The relationship between poly-P metabolism and VBNC formation under acid stress has only recently been identified and may represent a breakthrough in understanding this phenomenon and its impact on food safety.
- Published
- 2013
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269. Effect of CYP2C9 and VKORC1 genetic variations on warfarin dose requirements in Indian patients.
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Natarajan S, Ponde CK, Rajani RM, Jijina F, Gursahani R, Dhairyawan PP, and Ashavaid TF
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- Administration, Oral, Adult, Aged, Anticoagulants metabolism, Aryl Hydrocarbon Hydroxylases metabolism, Chi-Square Distribution, Cytochrome P-450 CYP2C9, Drug Dosage Calculations, Drug Monitoring, Female, Genotype, Humans, India, International Normalized Ratio, Logistic Models, Male, Middle Aged, Multivariate Analysis, Odds Ratio, Pharmacogenetics, Phenotype, Vitamin K Epoxide Reductases metabolism, Warfarin metabolism, Anticoagulants administration & dosage, Aryl Hydrocarbon Hydroxylases genetics, Blood Coagulation drug effects, Blood Coagulation genetics, Polymorphism, Genetic, Vitamin K Epoxide Reductases genetics, Warfarin administration & dosage
- Abstract
Background: Warfarin, an oral anticoagulant is used in patients who are at increased risk of developing blood clots. The management of warfarin therapy is challenging because it shows large inter and intra individual variability in patient response due to factors like age, gender, diet, concurrent drug interactions and variations in CYP2C9 and VKORC1 genes. Studies implicate that polymorphisms in VKORC1 and CYP2C9 genes are associated with reduced doses of warfarin. The aim of our current study was to characterize the effects of VKORC1 and CYP2C9 gene variations that contribute to variability in warfarin dosing in Indian patients., Methods: Genomic DNA was extracted from 103 patients undergoing warfarin therapy. Their mean daily warfarin dose, INR and demographics were recorded and genotyping of VKORC1 and CYP2C9 gene was performed by PCR-RFLP method., Results: Individuals with wild type genotypes required highest mean warfarin dosage of 4.72 mg/day while VKORC1 variants required 3.6 mg/day to maintain their therapeutic INR. CYP2C9*2 genotype was not found to affect the warfarin maintenance dosages. The odds ratio for developing supra therapeutic INR in patients carrying VKORC1 variant allele when compared to wild types was 13.96 (95% CI; 4.85 - 44.65. Other factors affecting warfarin dosages were age and weight., Conclusion: Inclusion of pharmacogenetic data along with clinical parameters would help better predict warfarin doses in Indian patients.
- Published
- 2013
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270. Cardiovascular disease in India.
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Ashavaid TF, Ponde CK, Shah S, and Jawanjal M
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- Biomarkers metabolism, Cardiovascular Diseases metabolism, Humans, India epidemiology, Risk Factors, Cardiovascular Diseases epidemiology
- Abstract
Cardiovascular disease (CVD) is one of the leading cause of mortality in India. It is estimated that 23.6 million CVD cases will be reported in subjects younger than 40 years of age by 2015, suggesting that young Indians are at higher cardiac risk. Evaluation of biomarkers in acute coronary syndrome (ACS) and at various stages of the disease such as inflammation, ischemia, and heart failure would indeed help to assess cardiac risk in Indian subjects. Identification of newer genetic markers through the candidate and/or genome-wide association approach would prove to be beneficial in developing a diagnostic assay for screening young asymptomatic Indian subjects.
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- 2012
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271. A 13-week dietary toxicity study in rats of a Napin-Rich Canola Protein Isolate.
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Mejia LA, Korgaonkar CK, Schweizer M, Chengelis C, Novilla M, Ziemer E, Williamson-Hughes PS, Grabiel R, and Empie M
- Subjects
- Animals, Behavior, Animal drug effects, Eating drug effects, Female, Male, Motor Activity drug effects, No-Observed-Adverse-Effect Level, Rats, Rats, Sprague-Dawley, Toxicity Tests, 2S Albumins, Plant toxicity, Body Weight drug effects, Brassica napus chemistry
- Abstract
The objective was to study the safety of a Napin-Rich Canola Protein Isolate (NRCPI) fed to rats at various levels for 13-weeks. The study included four groups (20 animals/sex/group) of young Sprague Dawley rats. They were fed ad libitum with an AIN-93G based protein-free diet containing, respectively, 5%, 10% and 20% (w/w) NRCPI (test article) or 20% (w/w) vitamin-free casein (control article). Protein levels were adjusted at 18% in all groups with vitamin-free casein. Body weights, food consumption, locomotor activity and behavioral and clinical pathology parameters were recorded at various points in the study, followed by macroscopic examination, determination of organ weights and microscopic examination at termination. There were no test article-related effects on ophthalmology, functional observations, hematology, serum chemistry, urinalysis, organ weights and macroscopic or microscopic findings. Lower body weight gains were observed in the 10% NRCPI-treated males and the 20% NRCPI-treated males and females. The lower body weight gains were associated with significantly lower food consumption. Therefore, for NRCPI the No Observed Adversed Effect Level (NOAEL) was considered to be 20% (the highest fed level); equivalent to 12.46 g/kg BW/day for males and 14.95 g/kg BW/day for females. The NRCPI was considered safe under the tested conditions.
- Published
- 2009
- Full Text
- View/download PDF
272. Evaluation of estrogenic activity of alcoholic extract of rhizomes of Curculigo orchioides.
- Author
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Vijayanarayana K, Rodrigues RS, Chandrashekhar KS, and Subrahmanyam EV
- Subjects
- Animals, Body Weight drug effects, Diethylstilbestrol pharmacology, Dose-Response Relationship, Drug, Ethanol, Female, Organ Size drug effects, Ovariectomy, Plant Extracts pharmacology, Plant Roots chemistry, Rats, Rats, Sprague-Dawley, Solvents, Uterus cytology, Uterus drug effects, Uterus metabolism, Vagina pathology, Curculigo chemistry, Estrogens, Non-Steroidal pharmacology
- Abstract
The rhizomes of Curculigo orchioides Gaertn. (Amaryllidacea) is an important Ayurvedic as well as Unani drug. It is present in several drug formulations used in the treatment of menorrhagia and other gynecological problems. In this study, we conducted a comparative study of estrogenic activity of alcoholic extract of Curculigo orchioides with diethylstilbestrol in bilaterally ovariectomized young albino rats. Bilaterally ovariectomized albino rats were divided into five groups (n=9) receiving different treatments, consisting of vehicle (0.6% w/v sodium carboxy methyl cellulose), ethanolic extract of rhizomes of Curculigo orchioides at three different doses (viz., 300, 600, 1200 mg/kg body weight) and standard drug diethylstilbestrol (DES) at a dose of 2 mg/kg body weight. All these were administered orally daily for 7 days. Estrogenic activity was assessed by taking percentage vaginal cornification, uterine wet weight, uterine glycogen content and uterine histology as parameters of assessment. Alcoholic extract of Curculigo orchioides showed a significant increase in percentage vaginal cornification, uterine wet weight (P<0.001), uterine glycogen content (P<0.001) and a proliferative changes in uterine endometrium compared to the control.
- Published
- 2007
- Full Text
- View/download PDF
273. Issues related to disability in India: a focus group study.
- Author
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Pal HR, Saxena S, Chandrashekhar K, Sudha SJ, Murthy RS, Thara R, Srinivasan TN, Gupta D, and Singh U
- Subjects
- Disability Evaluation, Focus Groups, Government Programs, Health Knowledge, Attitudes, Practice, Humans, India, Persons with Mental Disabilities, Prejudice, Disabled Persons classification, Disabled Persons legislation & jurisprudence
- Abstract
Background: Systematic research into disability has been scarce, especially from India, even though an estimated 5% of the population may have significant disability due to physical disorders. Depression as a common psychiatric disorder affects about 3%-5% of the population. Thus, the impact of disability related to physical, mental and substance use disorders is enormous and it influences resource allocation and policy planning., Methods: The issues relating to disability were addressed through a qualitative multicentered study. Focus groups were conducted at three sites in Chennai, Bangalore and Delhi on three themes: (i) parity, stigmatization and social participation; (ii) current practices and needs; and (iii) the General Disability Model as proposed by the World Health Organization. The focus groups were homogeneous and included members from six categories of participants: individuals with physical disability, individuals with mental disability, individuals with alcohol/drug-related disability, family members of mentally disabled persons, family members of physically disabled persons and health professionals. In all, 118 groups were conducted with a mean (SD) group size of 8.6 (1.6)., Results: Patients with mental and alcohol/drug-related disability were more discriminated against than those with physical disability. Awareness regarding the existing laws and social programmes was uniformly poor across the three centres. Stigmatization was a major reason for under-utilization of the meagre resources available. There was poor awareness of the Disability Act, 1996. The consumers felt more comfortable with the earlier terms of 'handicap' and 'impairment'., Conclusions: The study has implications for policy planning, clinical decision-making and social behaviour. Awareness of the laws, facilities and programmes needs to be increased, especially regarding the Disability Act, 1996 among consumers as well as health professionals. More disability-friendly facilities are required.
- Published
- 2000
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