Self-Energy Effects on the Low- to High-Energy Electronic Structure of SrVO3

The correlated electronic structure of SrVO3 has been investigated by angle-resolved photoemission spectroscopy using in-situ prepared thin films. Pronounced features of band renormalization have been observed: a sharp kink ~60 meV below the Fermi level (EF) and a broad so-called "high-energy kink" ~0.3 eV below EF as in the high-Tc cuprates although SrVO3 does not show magnetic fluctuations. We have deduced the self-energy in a wide energy range by applying the Kramers-Kronig relation to the observed spectra. The obtained self-energy clearly shows a large energy scale of ~0.7 eV which is attributed to electron-electron interaction and gives rise to the ~0.3 eV "kink" in the band dispersion as well as the incoherent peak ~1.5eV below EF. The present analysis enables us to obtain consistent picture both for the incoherent spectra and the band renormalization.Comment: 5 pages, 3 figure

Suppression subtractive hybridization coupled with microarray analysis to examine differential expression of genes in virus infected cells

High throughput detection of differential expression of genes is an efficient means of identifying genes and pathways that may play a role in biological systems under certain experimental conditions. There exist a variety of approaches that could be used to identify groups of genes that change in expression in response to a particular stimulus or environment. We here describe the application of suppression subtractive hybridization (SSH) coupled with cDNA microarray analysis for isolation and identification of chicken transcripts that change in expression on infection of host cells with a paramyxovirus. SSH was used for initial isolation of differentially expressed transcripts, a large-scale validation of which was accomplished by microarray analysis. The data reveals a large group of regulated genes constituting many biochemical pathways that could serve as targets for future investigations to explore their role in paramyxovirus pathogenesis. The detailed methods described herein could be useful and adaptable to any biological system for studying changes in gene expression

Direct Infection and Replication of Naturally Occurring Hepatitis C Virus Genotypes 1, 2, 3 and 4 in Normal Human Hepatocyte Cultures

Hepatitis C virus (HCV) infection afflicts about 170 million individuals worldwide. However, the HCV life cycle is only partially understood because it has not been possible to infect normal human hepatocytes in culture. The current Huh-7 systems use cloned, synthetic HCV RNA expressed in hepatocellular carcinoma cells to produce virions, but these cells cannot be infected with naturally occurring HCV obtained from infected patients.Here, we describe a human hepatocyte culture permissible to the direct infection with naturally occurring HCV genotypes 1, 2, 3 and 4 in the blood of HCV-infected patients. The culture system mimics the biology and kinetics of HCV infection in humans, and produces infectious virions that can infect naïve human hepatocytes.This culture system should complement the existing systems, and may facilitate the understanding of the HCV life cycle, its effects in the natural host cell, the hepatocyte, as well as the development of novel therapeutics and vaccines

An Integrated Transcriptomic and Meta-Analysis of Hepatoma Cells Reveals Factors That Influence Susceptibility to HCV Infection

Hepatitis C virus (HCV) is a global problem. To better understand HCV infection researchers employ in vitro HCV cell-culture (HCVcc) systems that use Huh-7 derived hepatoma cells that are particularly permissive to HCV infection. A variety of hyper-permissive cells have been subcloned for this purpose. In addition, subclones of Huh-7 which have evolved resistance to HCV are available. However, the mechanisms of susceptibility or resistance to infection among these cells have not been fully determined. In order to elucidate mechanisms by which hepatoma cells are susceptible or resistant to HCV infection we performed genome-wide expression analyses of six Huh-7 derived cell cultures that have different levels of permissiveness to infection. A great number of genes, representing a wide spectrum of functions are differentially expressed between cells. To focus our investigation, we identify host proteins from HCV replicase complexes, perform gene expression analysis of three HCV infected cells and conduct a detailed analysis of differentially expressed host factors by integrating a variety of data sources. Our results demonstrate that changes relating to susceptibility to HCV infection in hepatoma cells are linked to the innate immune response, secreted signal peptides and host factors that have a role in virus entry and replication. This work identifies both known and novel host factors that may influence HCV infection. Our findings build upon current knowledge of the complex interplay between HCV and the host cell, which could aid development of new antiviral strategies

New treatments for chronic hepatitis C

Treatments for chronic hepatitis C has evolved significantly in the past 15 years. The standard of care (SOC) is peginterferon alfa-2a/-2b with ribavirin for 48 weeks or 24 weeks in patients infected with HCV genotype 1 or 2/3, respectively. The treatment duration can be individualized based on the baseline viral load and the speed of the virologic response during treatment. However, current therapies are associated with side effects, complications, and poor patient tolerability. Therefore, there is an urgent need to identify better strategies for treating this disease. An improved sustained virologic response (SVR) can be achieved with new HCV-specific inhibitors against NS3/4A and NS5B polymerases. Recent trials have found SVR rates in patients with HCV genotype 1 infection of 61~68% and 67~75% for combining the SOC with the protease inhibitors telaprevir and boceprevir, respectively. Several new HCV-specific inhibitors such as protease inhibitors and nucleoside and non-nucleoside polymerase inhibitors as well as non-HCV-specific compounds with anti-HCV activity are currently in clinical evaluation. In this review we discuss these new treatments for chronic hepatitis C

Murine Coronavirus Requires Lipid Rafts for Virus Entry and Cell-Cell Fusion but Not for Virus Release

Thorp and Gallagher first reported that depletion of cholesterol inhibited virus entry and cell-cell fusion of mouse hepatitis virus (MHV), suggesting the importance of lipid rafts in MHV replication (E. B. Thorp and T. M. Gallagher, J. Virol. 78:2682-2692, 2004). However, the MHV receptor is not present in lipid rafts, and anchoring of the MHV receptor to lipid rafts did not enhance MHV infection; thus, the mechanism of lipid rafts involvement is not clear. In this study, we defined the mechanism and extent of lipid raft involvement in MHV replication. We showed that cholesterol depletion by methyl β-cyclodextrin or filipin did not affect virus binding but reduced virus entry. Furthermore, MHV spike protein bound to nonraftraft membrane at 4°C but shifted to lipid rafts at 37°C, indicating a redistribution of membrane following virus binding. Thus, the lipid raft involvement in MHV entry occurs at a step following virus binding. We also found that the viral spike protein in the plasma membrane of the infected cells was associated with lipid rafts, whereas that in the Golgi membrane, where MHV matures, was not. Moreover, the buoyant density of the virion was not changed when MHV was produced from the cholesterol-depleted cells, suggesting that MHV does not incorporate lipid rafts into the virion. These results indicate that MHV release does not involve lipid rafts. However, MHV spike protein has an inherent ability to associate with lipid rafts. Correspondingly, cell-cell fusion induced by MHV was retarded by cholesterol depletion, consistent with the association of the spike protein with lipid rafts in the plasma membrane. These findings suggest that MHV entry requires specific interactions between the spike protein and lipid rafts, probably during the virus internalization step