实验动物技术

Intact, enveloped coronavirus particles vary widely in size and contour, and are thus refractory to study by traditional structural means such as X-ray crystallography. Electron microscopy (EM) overcomes some problems associated with particle variability and has been an importa ...

Chicken tracheal organ cultures (TOCs), comprising transverse sections of chick embryo trachea with beating cilia, have proved useful in the isolation of several respiratory viruses and as a viral assay system, using ciliostasis as the criterion for infection. A simple technique for the ...

Calculation of infectious viral titers represents a basic and essential experimental approach for virologists. Classical plaque assays cannot be used for viruses that do not cause significant cytopathic effects, which is the case for strains 229E and OC43 of human coronavirus (HCoV). An ...

In general, a whole virion serves as a simple vaccine antigen and often essential material for the analysis of immune responses against virus infection. However, to work with highly contagious pathogens, it is necessary to take precautions against laboratory-acquired infection. We have ...

The embryonated egg is a complex structure comprising an embryo and its supporting membranes (chorioallantoic, amniotic, yolk). The developing embryo and its membranes provide the diversity of cell types that are needed for successful replication of a wide variety of different viruse ...

Virus discovery based on cDNA-AFLP (amplified fragment length polymorphism) (VIDISCA) is a novel approach that provides a fast and effective tool for amplification of unknown genomes, e.g., of human pathogenic viruses. The VIDISCA method is based on double restriction enzyme processi ...

Severe acute respiratory syndrome is a novel human disease caused by a coronavirus of animal origin. Soon after the discovery SARS-CoV, several molecular assays were described for the detection of this virus. Of these, conventional and quantitative RT-PCR approaches were the primary too ...

Group 2a of the Coronaviridae family contains human and animal pathogens that include mouse hepatitis virus, rat coronavirus, human respiratory coronaviruses OC43 and the recently identified HKU1 strain, a newly recognized canine respiratory coronavirus, porcine hemagglut ...

Of the many primer combinations that we have investigated for the detection of avian coronaviruses, two have worked better than any of the others: they worked with the largest number of strains/samples of a given coronavirus and the most species of avian coronavirus, and they also produced the most ...

A remarkably conserved 43-nucleotide-long motif present at the 3′-end of the genomes of several members of the polyadenylated RNA virus families Astroviridae, Coronaviridae, and Picornaviridae can be used for the detection and sequence characterization of the viruses harboring i ...

The zoonotic transmission of SARS coronavirus from animals to humans revealed the potential impact of coronaviruses on mankind. This incident also triggered several surveillance programs to hunt for novel coronaviruses in human and wildlife populations. Using classical RT-PCR ...

The recent discoveries of novel human coronaviruses, including the coronavirus causing SARS, and the previously unrecognized human coronaviruses HCoV-NL63 and HCoV-HKU1, indicate that the family Coronaviridae harbors more members than was previously assumed. All human coro ...

Since the advent of efficient cell-culture methods for HCV replication and, more recently, infection, there has been a need to efficiently sequence the viral RNA in these systems. This need is especially urgent in light of the error-prone nature of HCV RNA replication, which leads to a variety of int ...

Subgenomic replicons have been the first efficient cell-culture system for HCV and still are a valuable tool for studying different aspects of RNA replication. A variety of replicons based on different viral isolates and vector designs have been established. Here, I give a brief overview of vi ...

RNA replication of HCV occurs in the multiprotein complexes associated with the endoplasmic reticular (ER) membranes. The HCV NS3 to NS5B proteins are necessary and sufficient for HCV RNA replication in the cell, but cellular proteins in the HCV replication complex (RC) have not been determi ...

HCV replication complexes are well-organized protein and lipid structures responsible for HCV RNA replication. The nonstructural protein NS5B, an RNA-dependent RNA polymerase, is the catalytic subunit of these replication complexes. After being isolated from HCV replicon-c ...

Formation of a membrane-associated replication complex, composed of viral proteins, replicating RNA, altered cellular membranes, and other host factors, is a hallmark of all positive-strand RNA viruses. In the case of HCV, RNA replication takes place in a likely endoplasmic reticulum– ...

Interferon regulatory factor 3 (IRF-3) is a ubiquitously expressed latent cellular transcription factor that plays a pivotal role in control of innate, type I interferon (IFN) antiviral responses. After viral infections, IRF-3 is activated by specific C-terminal phosphorylation, ...

Because HCV RNA-dependent RNA polymerase is error-prone and the viral RNA has a high turnover rate, the genetic diversity of HCV is very high both in vitro and in vivo. The mutation rate in long-term replicon cultures approaches 3.0 � 10-3 base substitutions/site/year in this in vitro replication mo ...

Efforts to find effective treatment for hepatitis C virus (HCV) have been hampered by the lack of a robust in vitro infectious tissue-culture system for this virus. A subgenomic replicon system was first developed in 1999 and has since been extensively optimized to accommodate the need for conv ...