Exponential Spread of Hepatitis C Virus Genotype 4a in Egypt

Hepatitis C virus (HCV) infects >10% of the general population in Egypt, in which intravenous injection with an antimony compound for endemic schistosomiasis in the past has been implicated. To simulate the epidemic history of HCV in Egypt, sera were obtained from 3608 blood donors at 13 governorates in or surrounding the Nile valley during 1999. The prevalence of antibody to HCV (anti-HCV) and genotypes was determined in them, and the molecular evolutionary analysis based on the neutral theory was applied to HCV isolates of genotype 4a, which is outstandingly prevalent in Egypt and indigenous there. Of 3608 sera, 317 (8.8%) were positive for anti-HCV. The molecular evolutionary analysis on 47 HCV genotype 4a isolates of carriers from various districts in Egypt indicated that the spread of HCV-4a would have increased exponentially during the 1940s through 1980 when oral medications became available. In conclusion, the estimated spread time is consistent with the duration of intravenous antimony campaigns in Egypt.     

DNA sequence recognition by an isopropyl substituted thiazole polyamide

We have used DNA footprinting and fluorescence melting experiments to study the sequence-specific binding of a novel minor groove binding ligand (thiazotropsin A), containing an isopropyl substituted thiazole polyamide, to DNA. In one fragment, which contains every tetranucleotide sequence, sub-micromolar concentrations of the ligand generate a single footprint at the sequence ACTAGT. This sequence preference is confirmed in melting experiments with fluorescently labelled oligonucleotides. Experiments with DNA fragments that contain variants of this sequence suggest that the ligand also binds, with slightly lower affinity, to sequences of the type XCYRGZ, where X is any base except C, and Z is any base except G.     

The role of calcium,NF-κB and NFAT in the regulation of CXCL8 and IL-6 expression in Jurkat T-cells

T-cells play an important role in host immunity against invading pathogens. Determining the underlying regulatory mechanisms will provide a better understanding of T-cell-derived immune responses. In this study, we have shown the differential regulation of IL-6 and CXCL8 by NF-κB and NFAT in Jurkat T-cells, in response to PMA, heat killed Escherichia coli and calcium. CXCL8 was closely associated with the activation pattern of NFAT, while IL-6 expression was associated with NF-κB. Furthermore, increasing the intracellular Ca²⁺ concentration by calcium ionophore treatment of the cells resulted in NFAT induction without affecting the NF-κB activity. Interestingly, NF-κB activation by heat killed E. coli, as well as CXCL8 and IL-6 expression was significantly suppressed following addition of the calcium ionophore. This indicates that calcium plays an important role in regulating protein trafficking and T-cell signalling, and the subsequent inflammatory gene expression infers an involvement of NFAT in CXCL8 regulation.Understanding these regulatory patterns provide clarification of conditions that involve altered intracellular signalling leading to T-cell-derived cytokine expression.     

Modifications of antioxidant activity and protein composition of bean leaf due to <Emphasis Type="Italic">Bean yellow mosaic virus</Emphasis> infection and salicylic acid treatments

The antioxidant status as well as protein composition of faba bean leaves infected with Bean yellow mosaic virus (BYMV) and the effect of salicylic acid application was examined in this paper. Some modifications in the antioxidant status were observed by changing some antioxidant enzymes activities and contents of antioxidant metabolites. BYMV-infected leaves revealed POD, CAT, APX and SOD induced activities while SA treatments could inhibit POD, CAT activities but induced SOD activity. The enzyme activities seemed to be SA concentration dependant. Higher H₂O₂ and MDA concentrations were recorded in virus-infected leaves than those of the corresponding controls while treatment with SA followed by virus inoculation caused lowering of MDA concentration and reducing the damage due to lipid peroxidation. Moreover, because of virus infection and/or SA treatments, an increase in the amounts of phenolics and flavonoids was noticed. As compared to the control, BYMV infection or SA application caused pronounced increase in the antioxidant activity of leaf extracts detected by DPPH assay, indicating an increase in the amounts of antioxidant compounds occurred. To test the protein composition, the contents of each protein fractions (soluble, insoluble and total) were analyzed and the change in protein patterns was visualized using SDS-PAGE. The BYMV-infected bean leaves had protein contents higher than the control indicating accumulation of pathogenesis-related proteins. Moreover, spraying SA with or without virus inoculation could accumulate soluble, insoluble and total proteins and the pattern of increase was in accordance with SA concentration. Alterations in protein patterns were observed in faba bean leaves (Vicia faba cv Giza 461) in response to BYMV infection and SA treatments. Because of BYMV infection and SA treatments, the protein profiles showed new bands in comparison to the control. Some polypeptides were highly accumulated in treatments of SA followed by virus inoculation. Changing antioxidant status and accumulation of some antioxidant metabolites as well as the pronounced alterations in the protein composition indicate a kind of plant response against pathogen invasion and in case of SA treatment it is considered a way by which a defence response was initiated and/or activated.     

Organic acids,sugars, vitamin C content and some pomological characteristics of eleven hawthorn species (Crataegus spp.) from Turkey

Background

The Hawthorn (Crateagus sp.) mostly occurs around the temperate region of the world with a high number of species, producing a fruit with numerous beneficial effects for human health. The aim of the study was to determine organic acid and sugar contents in the fruit of a number of hawthorn species grown in Erzincan province of Turkey.

Results

Citric acid was the predominant organic acid in all hawthorn species and C. pseudoheterophylla had the highest citric acid content (23.688 g/100 g). There were not statistically significant differences among hawthorn species (except C. atrosanguinea Pojark) in terms of fumaric acid content. C.pontica C.Koch had a higher content of vitamin C (9.418 mg/100 g) compared to other species. Fructose was the predominant sugar component in all species and C. monogyna subsp. monogyna Joiq had the highest fructose content (18.378 g/100 g).

Conclusions

The high fruit quality of the studied species indicates the importance of this fruit in human nutrition as a natural source. The study revealed that there were differences in terms of fruit characteristics among hawthorn species and thus better quality hawthorn genotypes can be selected within the species. Hence, this study is considered to be a valuable reference for forthcoming studies. The high fruit quality of the studied species indicates the importance of this fruit in human nutrition as a natural source.     

Distinct structural elements in the first membrane-spanning segment of the epithelial sodium channel

Epithelial Na+ channels (ENaCs) comprise three subunits that have been proposed to be arranged in either an alpha2betagamma or a higher ordered configuration. Each subunit has two putative membrane-spanning segments (M1 and M2), intracellular amino and carboxyl termini, and a large extracellular loop. We have used the TOXCAT assay (a reporter assay for transmembrane segment homodimerization) to identify residues within the transmembrane segments of ENaC that may participate in important structural interactions within ENaC, with which we identified a candidate site within alphaM1. We performed site-directed mutagenesis at this site and found that, although the mutants reduced channel activity, ENaC protein expression at the plasma membrane was unaffected. To deduce the role of alphaM1 in the pore structure of ENaC, we performed tryptophan-scanning mutagenesis throughout alphaM1 (residues 110-130). We found that mutations within the amino-terminal part of alphaM1 had effects on activity and selectivity with a periodicity consistent with a helical structure but no effect on channel surface expression. We also observed that mutations within the carboxyl-terminal part of alphaM1 had effects on activity and selectivity but with no apparent periodicity. Additionally, these mutants reduced channel surface expression. Our data support a model in which the amino-terminal half of alphaM1 is alpha-helical and packs against structural element(s) that contribute to the ENaC pore. Furthermore, these data suggest that the carboxyl-terminal half of alphaM1 may be helical or assume a different conformation and may be involved in tertiary interactions essential to proper channel folding or assembly. Together, our data suggest that alphaM1 is divided into two distinct regions.     

Decreased complex II respiration and HNE-modified SDH subunit in diabetic heart

Several lines of research suggest that mitochondria play a role in the etiopathogenesis of diabetic cardiomyopathy, although the mechanisms involved are still debated. In the present study, we report that State 3 oxygen consumption decreases by approximately 35% with glutamate and by approximately 30% with succinate in mitochondria from diabetic rat hearts compared to controls. In these mitochondria the enzymatic activities of complex I and complex II are also decreased to a comparable extent. Western blot analysis of mitochondrial protein pattern using antibodies recognizing proteins modified by the lipid peroxidation product 4-hydroxynonenal indicates the FAD-containing subunit of succinate dehydrogenase as one of the targets of this highly reactive aldehyde. In rats diabetic for 6 or 12 weeks, insulin supplementation for 2 weeks decreases the level of protein modified by 4-hydroxynonenal and restores mitochondrial respiration and enzyme activity to control level. Taken together, these results: (1) indicate that 4-hydroxynonenal is endogenously produced within diabetic mitochondria and forms an adduct with selective mitochondrial proteins, (2) identify one of these proteins as a subunit of succinate dehydrogenase, and (3) provide strong evidence that insulin treatment can reverse and ameliorate free radical damage and mitochondrial function under diabetic conditions.     

Inhibitory tract traps the epithelial Na+ channel in a low activity conformation

Proteolysis plays an important role in the maturation and activation of epithelial Na(+) channels (ENaCs). Non-cleaved channels are inactive at high extracellular Na(+) concentrations and fully cleaved channels are constitutively active. Cleavage of the α and γ subunits at multiple sites activates the channel through the release of imbedded inhibitory tracts. Peptides derived from these released tracts are also inhibitory, likely through binding at the inhibitory tract sites. We recently reported a model of the α subunit. We have now cross-linked Cys derivatives of the inhibitory peptide to the channel, using our model to predict sites at a domain interface of the α subunit that is in proximity to the N terminus of the peptide. Furthermore, peptide inhibition was mimicked in the absence of peptide by cross-linking the channel across the domain interface. Our results suggest a dynamic domain interface that can be exploited by inhibitory peptides and provides a mechanism for peptide inhibition and proteolytic activation.