Rakesh Sharma

Bio: Rakesh Sharma is an academic researcher from Indian Institute of Technology, Jodhpur. The author has contributed to research in topics: Medicine & Catalysis. The author has an hindex of 60, co-authored 673 publications receiving 14157 citations. Previous affiliations of Rakesh Sharma include University of Grenoble & Centre national de la recherche scientifique.

CopA: An Escherichia coli Cu(I)-translocating P-type ATPase

Abstract: The copA gene product, a putative copper-translocating P-type ATPase, has been shown to be involved in copper resistance in Escherichia coli. The copA gene was disrupted by insertion of a kanamycin gene through homologous recombination. The mutant strain was more sensitive to copper salts but not to salts of other metals, suggesting a role in copper homeostasis. The copper-sensitive phenotype could be rescued by complementation by a plasmid carrying copA from E. coli or copB from Enterococcus hirae. Expression of copA was induced by salts of copper or silver but not zinc or cobalt. Everted membrane vesicles from cells expressing copA exhibited ATP-coupled accumulation of copper, presumably as Cu(I). The results indicate that CopA is a Cu(I)-translocating efflux pump that is similar to the copper pumps related to Menkes and Wilson diseases and provides a useful prokaryotic model for these human diseases.

High prevalence of diabetes, obesity and dyslipidaemia in urban slum population in northern India.

Abstract: BACKGROUND AND AIMS: In this study, a prevalence survey of various atherosclerosis risk factors was carried out on hitherto poorly studied rural–urban migrants settled in urban slums in a large metropolitan city in northern India, with the aim of studying anthropometric and metabolic characteristics of this population in socio-economic transition. DESIGN: A cross-sectional epidemiological descriptive study. SUBJECTS: A total of 532 subjects (170 males and 362 females) were included in the study (response rate approximately 40%). METHODS AND RESULTS: In this study, diabetes mellitus was recorded in 11.2% (95% CI 6.8–16.9) of males and 9.9% (95% CI 7.0–13.5) of females, the overall prevalence being 10.3% (95% CI 7.8–13.2). Based on body mass index (BMI), obesity was more prevalent in females (15.6%; 95% CI 10.7–22.3) than in males (13.3%; 95% CI 8.5–19.5). On the other hand, classifying obesity based on percentage body fat (%BF), 10.6% (95% CI 6.4–16.2) of males and 40.2% (95% CI 34.9–45.3) of females were obese. High waist–hip ratio (WHR) was observed in 9.4% (95% CI 5.4–14.8) of males and 51.1% (95% CI 45.8–56.3) of the females. All individual skinfolds and sum of skinfolds were significantly higher in females (P 30%). Furthermore, total cholesterol and low-density lipoprotein cholesterol were high in both males and females. Stepwise multiple linear regression analysis showed that for both males and females BMI, WHR and %BF were positive predictors of biochemical parameters, except for HDL-c, for which these parameters were negatively associated. CONCLUSIONS: Appreciable prevalence of obesity, dyslipidaemia, diabetes mellitus, substantial increase in body fat, generalised and regional obesity in middle age, particularly in females, need immediate attention in terms of prevention and health education in such economically deprived populations.

Radioprotection by plant products: present status and future prospects.

Abstract: The development of radioprotective agents has been the subject of intense research in view of their potential for use within a radiation environment, such as space exploration, radiotherapy and even nuclear war. However, no ideal, safe synthetic radioprotectors are available to date, so the search for alternative sources, including plants, has been on going for several decades. In Ayurveda, the traditional Indian system of medicine, several plants have been used to treat free radical-mediated ailments and, therefore, it is logical to expect that such plants may also render some protection against radiation damage. A systematic screening approach can provide leads to identifying potential new candidate drugs from plant sources, for mitigation of radiation injury. This article reviews some of the most promising plants, and their bioactive principles, that are widely used in traditional systems of medicine, and which have rendered significant radioprotection in both in vitro and in vivo model systems. Plants and their constituents with pharmacological activities that may be relevant to amelioration of radiation-mediated damage, including antiemetic, antiinflammatory, antioxidant, cell proliferative, wound healing and haemopoietic stimulatories are also discussed.

Genome-wide prediction of G4 DNA as regulatory motifs: Role in Escherichia coli global regulation

Abstract: The role of nonlinear DNA in replication, recombination, and transcription has become evident in recent years. Although several studies have predicted and characterized regulatory elements at the sequence level, very few have investigated DNA structure as regulatory motifs. Here, using G-quadruplex or G4 DNA motifs as a model, we have researched the role of DNA structure in transcription on a genome-wide scale. Analyses of >61,000 open reading frames (ORFs) across 18 prokaryotes show enrichment of G4 motifs in regulatory regions and indicate its predominance within promoters of genes pertaining to transcription, secondary metabolite biosynthesis, and signal transduction. Based on this, we predict that G4 DNA may present regulatory signals. This is supported by conserved G4 motifs in promoters of orthologous genes across phylogenetically distant organisms. We hypothesized a regulatory role of G4 DNA during supercoiling stress, when duplex destabilization may result in G4 formation. This is in line with our observations from target site analysis for 55 DNA-binding proteins in Escherichia coli, which reveals significant (P 1000 genes in the early growth phase and are believed to be induced by supercoiled DNA. We also predict G4 motif-induced supercoiling sensitivity for >30 operons in E. coli, and our findings implicate G4 DNA in DNA-topology-mediated global gene regulation in E. coli.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Analysis of nanoparticle delivery to tumours

Abstract: This Perspective explores and explains the fundamental dogma of nanoparticle delivery to tumours and answers two central questions: ‘how many nanoparticles accumulate in a tumour?’ and ‘how does this number affect the clinical translation of nanomedicines?’