Effect of paraquat on cellular defense enzymes and glutathione level of Funalia trogii

The effect of paraquat on the activities of antioxidant defense and detoxifying enzymes of the white-rot fungusFunalia trogii was determined. Paraquat increased the activities of glutathione reductase (GR), glutathione transferase (GT) and superoxide dismutase at 1 mmol/L, while at 0.1 mmol/L it did not affect the activity of GR and GT. It depressed the catalase activity and the amount of glutathione at all concentrations used. Paraquat treatment probably depresses antioxidant defense components such as catalase and glutathione.     

Evaluation of heavy metals uptake by wheat growing in sewage water irrigated soil

Present research work was carried out in Sahiwal, Sargodha, Pakistan. Diverse treatments of domestic wastewater were used for ascertaining the contamination level in grains of wheat crop. Food crop exposure to heavy metals has been a subject of great concern due to potential health risks to humans. It was observed that increased proportion of wastewater resulted in elevation of heavy metals both in soil and wheat grains. The iron was found to be higher in comparison to all other studied metals in soil. Similarly, wheat grains had high Cd level. Cadmium had the highest values for daily metal intake, health risk index, and pollution load index. Except Co, all metals were positively and significantly correlated between wheat grains and soil. Zinc had the highest bioavailability due to its highest bioconcentration factor. Value of enrichment factor was highest for Mn. It was thus concluded, on the basis of this study, that wastewater-irrigated crops accumulate more metals. Treatment of wastewater prior to application to plants must be commonly practiced to save crops from contamination.     

Association of PON1 and PON2 Polymorphisms with PON1 Activity and Significant Coronary Stenosis in a Tunisian Population

PON1 and PON2 have attracted considerable attention as candidate genes for coronary heart disease because their enzymes function as key factors in lipoprotein catabolism pathways. We studied the distribution of PON1 and PON2 polymorphisms, including genotyping, lipid profile, and PON1 activity, and their association with PON1 activity and significant coronary stenosis (SCS) in a Tunisian population. PON1 activity was lower in patients with SCS than in controls. It increased with the R allele (QQ < QR < RR) in PON1-192 genotypes and with the L allele (MM < ML < LL) in PON1-55 genotypes. In the presence of metabolic syndrome and diabetes, PON1-192RR and PON2-311CC were associated with an increased risk of SCS and PON1-55MM seems to have lower risk. This association was evident among nonsmokers for PON1-55MM and among smokers for PON1-192RR and PON2-311CC. The GTGC haplotype seemed to increase the risk of SCS compared with the wild haplotype in a Tunisian population.     

Biocontrol and Plant Growth Promotion Characterization of Bacillus Species Isolated from Calendula officinalis Rhizosphere

The phenotypic and genotypic diversity of the plant growth promoting Bacillus genus have been widely investigated in the rhizosphere of various agricultural crops. However, to our knowledge this is the first report on the Bacillus species isolated from the rhizosphere of Calendula officinalis. 15 % of the isolated bacteria were screened for their important antifungal activity against Fusarium oxysporum, Botrytis cinerea, Aspergillus niger, Cladosporium cucumerinium and Alternaria alternata. The bacteria identification based on 16S r-RNA and gyrase-A genes analysis, revealed strains closely related to Bacillus amyloliquefaciens, B. velezensis, B. subtilis sub sp spizezenii and Paenibacillus polymyxa species. The electro-spray mass spectrometry coupled to liquid chromatography (ESI-LC MS) analysis showed that most of the Bacillus isolates produced the three lipopeptides families. However, the P. polymyxa (18SRTS) didn’t produce any type of lipopeptides. All the tested Bacillus isolates produced cellulase but the protease activity was observed only in the B. amyloliquefaciens species (9SRTS). The Salkowsky colorimetric test showed that the screened bacteria synthesized 6–52 μg/ml of indole 3 acetic acid. These bacteria produced siderophores with more than 10 mm wide orange zones on chromazurol S. The greenhouse experiment using a naturally infested soil with Sclerotonia sclerotiorum showed that the B. amyloliquefaciens (9SRTS) had no significant (P > 0.05) effect on the pre-germination of the chickpea seeds. However, it increased the size of the chickpea plants and reduced the stem rot disease (P < 0.05).These results suggested that the Bacillus strains isolated in this work may be further used as bioinoculants to improve the production of C. officinalis and other crop systems.     

Structural insight into a novel human CCR5-V130I variant associated with resistance to HIV-1 infection

We report the identification of a novel CC chemokine receptor 5 (CCR5) variant that seems associated with resistance to HIV-1 infection. The V130I mutation of the CCR5 receptor is located in the intracellular loop ICL2 known as DRY box and described in the literature as a nonsynonymous mutation present in nonhuman primates group. Extensive molecular modeling and dynamics simulations were performed to elucidate the mechanism by which the V130I mutation may induce conformational change of the CCR5 folding protein and prevent the interaction with the β-arrestin protein. Our study provides new mechanistic insight into how a specific mutation in the regulatory domain of CCR5 might alter the structural folding of the DRY box and the possible ICL2 loop binding with the β-arrestin protein, as described in our previous computational study. The results from our large-scale simulations complement recent experimental results and clinical features and offer useful insights into the mechanism behind CCR5 protein folding and signal transduction. In order for HIV, the entry of the virus to the cells must fuse with the CCR5 receptor that sits on the surface of T-helper immune cells. The described V130I mutation in the gene encoding the CCR5 protein may results in a defective CCR5-Arrestin binding complex that blocks entry of the virus.     

Molecular screening of phytochemicals from Amelanchier Alnifolia against HCV NS3 protease/helicase using computational docking techniques

Hepatitis C is serious health concern worldwide caused by HCV. It causes liver cirrhosis and hepato-cellular carcinoma. Development of prevention solutions is under progress. Meanwhile, the treatment of the viral disease using compounds isolated from natural medicinal plants is promising. The traditional use of photo-chemicals from medicinal plants like Amelanchier alnifolia for viral treatment is hopeful. Therefore, it is of interest to screen for flavonoids from Amelanchier alnifolia against protein targets of HCV. Hence, we assessed the binding of flavonoids to HCV NS3/4A protease and helicase proteins. Results show that Quercitin 3- galactoside and 3-glucosideshowed good binding score with protease and helicase respectively. Their interaction/binding sites are documented in this report. This data provide insights for the consideration of flavonoids as potential inhibitors of HCV/NS3/4A protease and helicase.     

Selection of Specific Protein Binders for Pre-Defined Targets from an Optimized Library of Artificial Helicoidal Repeat Proteins (alphaRep)

We previously designed a new family of artificial proteins named αRep based on a subgroup of thermostable helicoidal HEAT-like repeats. We have now assembled a large optimized αRep library. In this library, the side chains at each variable position are not fully randomized but instead encoded by a distribution of codons based on the natural frequency of side chains of the natural repeats family. The library construction is based on a polymerization of micro-genes and therefore results in a distribution of proteins with a variable number of repeats. We improved the library construction process using a “filtration” procedure to retain only fully coding modules that were recombined to recreate sequence diversity. The final library named Lib2.1 contains 1.7×10⁹ independent clones. Here, we used phage display to select, from the previously described library or from the new library, new specific αRep proteins binding to four different non-related predefined protein targets. Specific binders were selected in each case. The results show that binders with various sizes are selected including relatively long sequences, with up to 7 repeats. ITC-measured affinities vary with K_d values ranging from micromolar to nanomolar ranges. The formation of complexes is associated with a significant thermal stabilization of the bound target protein. The crystal structures of two complexes between αRep and their cognate targets were solved and show that the new interfaces are established by the variable surfaces of the repeated modules, as well by the variable N-cap residues. These results suggest that αRep library is a new and versatile source of tight and specific binding proteins with favorable biophysical properties.     

Partitioning of the plasma membrane Ca2+-ATPase into lipid rafts in primary neurons: effects of cholesterol depletion

Spatial and temporal alterations in intracellular calcium [Ca(2+)](i) play a pivotal role in a wide array of neuronal functions. Disruption in Ca(2+) homeostasis has been implicated in the decline in neuronal function in brain aging and in neurodegenerative disorders. The plasma membrane Ca(2+)-ATPase (PMCA) is a high affinity Ca(2+) transporter that plays a crucial role in the termination of [Ca(2+)](i) signals and in the maintenance of low [Ca(2+)](i) essential for signaling. Recent evidence indicates that PMCA is uniquely sensitive to its lipid environment and is stimulated by lipids with ordered acyl chains. Here we show that both PMCA and its activator calmodulin (CaM) are partitioned into liquid-ordered, cholesterol-rich plasma membrane microdomains or 'lipid rafts' in primary cultured neurons. Association of PMCA with rafts was demonstrated in preparations isolated by sucrose density gradient centrifugation and in intact neurons by confocal microscopy. Total raft-associated PMCA activity was much higher than the PMCA activity excluded from these microdomains. Depletion of cellular cholesterol dramatically inhibited the activity of the raft-associated PMCA with no effect on the activity of the non-raft pool. We propose that association of PMCA with rafts represents a novel mechanism for its regulation and, consequently, of Ca(2+) signaling in the central nervous system.