Hepatitis C virus molecular evolution:Transmission,disease progression and antiviral therapy

Hepatitis C virus(HCV)infection represents an important public health problem worldwide.Reduction of HCV morbidity and mortality is a current challenge owned to several viral and host factors.Virus molecular evolution plays an important role in HCV transmission,disease progression and therapy outcome.The high degree of genetic heterogeneity characteristic of HCV is a key element for the rapid adaptation of the intrahost viral population to different selection pressures(e.g.,host immune responses and antiviral therapy).HCV molecular evolution is shaped by different mechanisms including a high mutation rate,genetic bottlenecks,genetic drift,recombination,temporal variations and compartmentalization.These evolutionary processes constantly rearrange the composition of the HCV intrahost population in a staging manner.Remarkable advances in the understanding of the molecular mechanism controlling HCV replication have facilitated the development of a plethora of direct-acting antiviral agents against HCV.As a result,superior sustained viral responses have been attained.The rapidly evolving field of anti-HCV therapy is expected to broad its landscape even further with newer,more potent antivirals,bringing us one step closer to the interferon-free era.

Multiphasic characterization of a plant growth promoting bacterial strain, Burkholderia sp.7016 and its effect on tomato growth in the field

Aiming at searching for plant growth promoting rhizobacteria (PGPR), a bacterium strain coded as 7016 was isolated from soybean rhizosphere and was characterized in the present study. It was identiifed as Burkholderia sp. based on 16S rDNA sequence analysis, as wel as phenotypic and biochemical characterizations. This bacterium presented nitrogenase activity, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity and phosphate solubilizing ability;inhibited the growth of Sclerotinia sclerotiorum, Gibberel a zeae and Verticil ium dahliae;and produced smal quantities of indole acetic acid (IAA). In green house experiments, signiifcant increases in shoot height and weight, root length and weight, and stem diameter were observed on tomato plants in 30 d after inoculation with strain 7016. Result of 16S rDNA PCR-DGGE showed that 7016 survived in the rhizosphere of tomato seedlings. In the ifeld experiments, Burkholderia sp. 7016 enhanced the tomato yield and signiifcantly promoted activities of soil urease, phosphatase, sucrase, and catalase. Al these results demonstrated Burkholderia sp. 7016 as a valuable PGPR and a candidate of biofertilizer.

mRNA levels of TLR4 and TLR5 are independent of H pylori

AIM:To determine if the presence H pylori or its viru- lence affect toll-like receptor 4 (TLR4) and TLR5 mRNA expression levels. METHODS:For the in vivo assays, gastric biopsies were obtained from 40 patients and H pylori status was determined. For the in vitro assays, human gastric adenocarcinoma mucosal cells (AGS) were cultured in the presence or absence of twelve selected H pylori strains. H pylori strains isolated from culture-positive patients and selected strains were genotyped for cagA and vacA. The cDNA was obtained from mRNA extracted from biopsies and from infected AGS cells. TLR4 and TLR5 mRNA levels were examined by real-time PCR. RESULTS: The presence of H pylori did not affect the mRNA levels of TLR4 or TLR5 in gastric biopsies. The mRNA levels of both receptors were not influenced by the vacA status (P > 0.05 for both receptors) andthere were no differences in TLR4 or TLR5 mRNA levels among the different clinical presentations/histological fi ndings (P > 0.05). In the in vitro assay, the mRNA levels of TLR4 or TLR5 in AGS cells were not influenced by the vacAs1 status or the clinical condition as-sociated with the strains (P > 0.05 for both TLR4 and TLR5). CONCLUSION: The results of this study show that the mRNA levels of TLR4 and TLR5 in gastric cells, both in vivo and in vitro, are independent of H pylori colonization and suggest that vacA may not be a significant player in the first step of innate immune recognition mediated by TLR4 or TLR5.