Complement activation in heart diseases. Role of oxidants

Increasing evidence demonstrated that atherosclerosis is an immunologically mediated disease. Myocardial ischemia/reperfusion injury is accompanied by an inflammatory response contributing to reversible and irreversible changes in tissue viability and organ function. Three major components are recognized as the major contributing factors in reperfusion injury. These are: (1) molecular oxygen; (2) cellular blood elements (especially the neutrophils); and (3) components of the activated complement system. The latter two often act in concert. Endothelial and leukocyte responses are involved in tissue injury, orchestrated primarily by the complement cascade. Anaphylatoxins and assembly of the membrane attack complex contribute directly and indirectly to further tissue damage. Tissue damage mediated by neutrophils can be initiated by complement fragments, notably C5a, which are potent stimulators of neutrophil superoxide production and adherence to coronary artery endothelium. The complement cascade, particularly the alternative pathway, is activated during myocardial ischemia/reperfusion. Complement fragments such as the anaphylatoxins C3a and C5a, are produced both locally and systematically, and the membrane attack complex is deposited on cell membranes and subsequent release of mediators such as histamine and platelet activating factor (PAF), thereby causing an increase in vascular permeability with concomitant manifestation of cellular edema. Complement increases the expression of CD18 on the neutrophils and increases P-selectin expression on the surface of the endothelium. Mitochondria may be a source of molecules that activate complements during ischemia/reperfusion injury to myocardium, providing therewith a stimulus for infiltration of polymorphonuclear leukocytes. Tissue salvage can be achieved by depletion of complement components, thus making evident a contributory role for the complement cascade in ischemia/reperfusion injury. The complexities of the complement cascade provide numerous sites as potential targets for therapeutic interventions designed to modulate the complement response to injury. The latter is exemplified by the ability of soluble form of complement receptor 1 (sCR1) to decrease infarct size in in vitro models of ischemia/reperfusion injury. The mechanism(s) that initiates complement activation is not clearly known, although loss of CD59 (protectin) from cells compromised by ischemia/reperfusion may contribute to direct damage of the coronary vascular bed by the terminal complement complex. Therapeutic approaches to ischemia/reperfusion injury in general, and especially those involving complements, are at the very beginning and their potential benefits have still to be adequately evaluated. It may be noted that complement activation has both positive and negative effects and, therefore, might be modulated rather than abruptly blunted.     

Interactions of sulfur oxidation repressor with its promoters involve different binding geometries

The divergently transcribed sulfur oxidation (sox) operon of a sulfur chemolithotrophs, Pseudaminobacter salicylatoxidans KCT001, comprising sox TRS-VW-XYZABCD, is regulated by a repressor (SoxR). SoxR binds to two disparate operators, sv (present in between soxS and soxV) and wx (present in between soxW and soxX). Here we report details of the interaction between SoxR and these two operator regions of the sox operon, using methylation interference and hydroxyl radical footprinting. We propose that the sv operator is symmetric and compact, while the wx operator is asymmetric and extended. We report an interesting difference between the SoxR-sv interaction and the SoxR-wx interaction through a competition assay involving groove-specific ligands. SoxR binds in the major groove of the sv operator, but binds in the minor groove of the wx operator. The structural flexibility of the SoxR helps it to act differentially in its interactions with these two operators. Mutational analysis shows that SoxR uses different amino acid residues when binding to the sv operator versus the wx operator. Taken together, the results indicate that interaction between SoxR and the two operator sites involves different binding geometries. This makes SoxR the only known example of a ArsR-family protein that binds differentially to different operators.     

Association of Toll-like receptor (TLR) 2, 3 and 9 genes polymorphism with prostate cancer risk in North Indian population

Prostate cancer (PCa) is the most common cancer among men. It has been suggested that toll like receptors (TLRs) may contribute to PCa pathogenesis by stimulating prostate epithelial cell proliferation in response to infectious stimuli. We performed case control study to analyze the genetic variants of TLR2, 3 and 9 gene polymorphisms with PCa risk in a North Indian population. For this study we genotyped age matched, unrelated 195 PCa patients and 250 healthy controls of similar ethnicity in a case-control study. They were genotyped for TLR2 (-196 to -174 Del), TLR3 (c.1377C/T) [rs3775290] and TLR9 (G2848A) [rs352140] gene polymorphisms using polymerase chain reaction and restriction fragment length polymorphism method. Variant allele Del (D) carriers i.e. (ID + DD) of TLR2 (-196 to -174 Del) SNP, demonstrated 1.57 fold increased risk (p = 0.040; OR = 1.57, 95% CI = 1.02-2.24) as compared to Ins (I) allele, suggesting a dominant effect model involved in the risk of this polymorphism in PCa. However, variants of TLR3 and 9 gene polymorphisms were not associated with PCa risk. Our results suggested the low penetrance variant of TLR2 (-196 to -174 Del) to be at increased PCa risk in North Indian population. Functional studies in ethnically diverse populations may provide a more comprehensive involvement of innate immunity in identifying the disease-associated variants for PCa etiology.     

Spectroscopic investigation of collagen scaffolds impregnated with AgNPs coated by PEG/TX-100 mixed systems

Silver nanoparticles have received attention as novel antimicrobial agents due to their high surface area to volume ratio and the unique chemical and physical properties. In order to study the effects of capping agents on silver nanoparticles (AgNPs), the nanoparticles were synthesized via chemical reduction method using different concentrations (0.3 mM, 0.6 mM and 0.9 mM) of polyethylene glycol (PEG) and Triton X-100 (TX). Also, AgNPs capped by the combinations of both PEG and TX were synthesized. These coated AgNPs were incorporated into collagen, lyophilized to form scaffolds and characterized by FTIR and FT-Raman spectroscopy. Results on mechanical property of all the scaffolds displayed no significant difference in the percentage elongation at break. However, the maximum percentage of 46.67% was observed with the combinations (0.9 mM PEG+0.9 mM TX). This implies that the combinations of surfactants increase the elasticity, which is useful for biomedical applications, e.g., Heart-valve preparations.     

Biodegradation of asphalt by Garciaella petrolearia TERIG02 for viscosity reduction of heavy oil

Petroleum hydrocarbon is an important energy resource, but it is difficult to exploit due to the presence of dominated heavy constituents such as asphaltenes. In this study, viscosity reduction of Jodhpur heavy oil (2,637 cP at 50°C) has been carried out by the biodegradation of asphalt using a bacterial strain TERIG02. TERIG02 was isolated from sea buried oil pipeline known as Mumbai Uran trunk line (MUT) located on western coast of India and identified as Garciaella petrolearia by 16S rRNA full gene sequencing. TERIG02 showed 42% viscosity reduction when asphalt along with molasses was used as a sole carbon source compared to only asphalt (37%). The viscosity reduction by asphaltene degradation has been structurally characterized by Fourier transform infrared spectroscopy (FTIR). This strain also shows an additional preference to degrade toxic asphalt and aromatics compounds first unlike the other known strains. All these characteristics makes TERIG02 a potential candidate for enhanced oil recovery and a solution to degrading toxic aromatic compounds.     

Complete Genome Sequence,Phylogenetic Relationships and Molecular Diagnosis of an Indian Isolate of Potato Virus X

The complete genome of a Potato virus X (PVX) isolate from India (ptDel‐9), which occurred symptomlessly in potato but induced ringspots on Nicotiana tabacum cv. Xanthi and necrotic mosaic on Nicotiana benthamiana, was sequenced. The genome was 6435 nucleotides long ( JF430080 ) and contained five open reading frames. The isolate was closely related to those reported from the Eurasian region (95.1–97.1% sequence similarity) and distantly related to those reported from South America (77.2–77.9%). The CP gene was expressed in Escherichia coli as a 76‐kDa fusion protein with maltose‐binding protein and used to generate polyclonal antibodies, which successfully detected PVX in field samples of potato by ELISA. In 20% of field samples, for which ELISA failed, the virus was successfully detected by RT‐PCR. This is the first report of molecular characterization of PVX occurring in India.     

Virus–vector Relationships,Host Range,Detection and Sequence Comparison of Chilli leaf curl virus Associated with an Epidemic of Leaf Curl Disease of Chilli in Jodhpur,India

An epidemic of chilli leaf curl disease was recorded in 2004 in Jodhpur, a major chilli‐growing area in Rajasthan, India. Several isolates were efficiently transmitted by the whitefly (Bemisia tabaci), all of which induced severe leaf curl symptoms in chilli. A single whitefly was capable of transmitting the virus, and eight or more whiteflies per plant resulted in 100% transmission. The minimum acquisition access period (AAP) and inoculation access period (IAP) were 180 and 60 min, respectively. The virus persisted in whiteflies for up to 5 days postacquisition. Of 25 species tested, the virus infected only five (Capsicum annuum, Carica papaya, Solanum lycopersicum, Nicotiana tabacum and N. benthamiana). The virus was identified as Chilli leaf curl virus (ChiLCV), which shared the closest sequence identity (96.1%) with an isolate of ChiLCV from potato in Pakistan and showed sequence diversity up to 12.3% among the ChiLCV isolates reported from India and Pakistan. A betasatellite was identified, which resembled most closely (97.3%) that of Tomato leaf curl Bangladesh betasatellite previously reported from chilli and tomato leaf curl in India. The betasatellite was very different from that reported from chilli leaf curl in Pakistan, indicating that different betasatellites are associated with chilli leaf curl in India and Pakistan. We describe here for the first time the virus–vector relationships and host range of ChiLCV.     

Excessive zinc in diet induces leptin resistance in Wistar rat through increased uptake of nutrients at intestinal level

ProjectThe ob gene has either been found to be mutant defective resulting in a deficiency of its product leptin or leptin has been found to be resistant to its receptors in obese human and rodents. The factors inducing leptin resistance have not been identified. Since excessive bioavailability of Zn has been implicated in obesity, we investigated if its excess in diet induces leptin resistance.ProcedureFor the investigations, three groups of Wistar rats were included in this study and they were fed on equicalories semi synthetic basal diet containing 20 mg, 40 mg or 80 mg Zn/kg diet for 120 days. There after they were sacrificed for hormonal status and intestinal investigations.ResultsThe data of this study revealed that the food intake, gain in body weight, serum leptin, glucose, insulin, cortisol increased with increased Zn concentration in diet. TEM study showed a positive correlation between Zn concentration in diet and number of microvilli/unit surface area of the mucosal epithelial cells of the intestine.ConclusionThe results of this study suggest that excessive bioavailability of Zn induces leptin resistance through increased uptake of nutrients at intestinal level, leading to the growth of the fat cells which aggravated the leptin synthesis and its release in the blood stream. In spite of its higher circulating level, it was unable to reduce the food intake and gain in body weight in Zn treated rats equivalent to the control group.