Orwik

Hantaviruses in small mammals and humans in the coastal region of Zhejiang Province, China.

To gain more insights into the epidemiology of hantaviruses in the coastal region of Zhejiang Province, China, the morbidity and mortality of hemorrhagic fever with renal syndrome (HFRS) were analyzed in two coastal areas: Cixi (hilly terrain) and We... expand abstractnzhou (mountainous terrain). More HFRS cases have been reported in Cixi than in Wenzhou. Annual incidence rate of HFRS in Cixi had been on the level of approximately 1.5/100,000 from 1968 (when the first HFRS case was reported) to 2007, with the highest incidence rate of 8.54/100,000 in 1999. The annual incidence rate in Wenzhou has been relatively low, less than 0.5/100,000 since the first HFRS case was reported in 1981. A total of 461 rodents and 199 shrews were captured in these two areas. Hantavirus antibodies were detected in 16 of 241 (6.64%) Rattus norvegicus and 13 of 122 (10.66%) R. flavipectus. Interestingly, hantavirus antigens were identified in 6 of 196 (3.06%) Suncus murinus. Genetic analysis showed that partial M and S segment sequences recovered from rats in the two regions belong to Seoul virus (SEOV) and can be assigned into two genetic lineages. SEOV variants that belong to these two lineages of viruses are distributed widely in China and have been found outside China. As most trapped rodents were rats and SEOV was the only hantavirus detected, these results suggested that SEOV plays an important role in human hantavirus infections. They also reinforce the need for vigilance in preventing HFRS caused by hantaviruses in the coastal region. collapse abstract

The roles of chemokines in rabies virus infection: overexpression may not always be beneficial.

It was found previously that induction of innate immunity, particularly chemokines, is an important mechanism of rabies virus (RABV) attenuation. To evaluate the effect of overexpression of chemokines on RABV infection, chemokines macrophage inflamma... expand abstracttory protein 1alpha (MIP-1alpha), RANTES, and IP-10 were individually cloned into the genome of attenuated RABV strain HEP-Flury. These recombinant RABVs were characterized in vitro for growth properties and expression of chemokines. It was found that all the recombinant viruses grew as well as the parent virus, and each of the viruses expressed the intended chemokine in a dose-dependent manner. When these viruses were evaluated for pathogenicity in the mouse model, it was found that overexpression of MIP-1alpha further decreased RABV pathogenicity by inducing a transient innate immune response. In contrast, overexpression of RANTES or IP-10 increased RABV pathogenicity by causing neurological diseases, which is due to persistent and high-level expression of chemokines, excessive infiltration and accumulation of inflammatory cells in the central nervous system, and severe enhancement of blood-brain barrier permeability. These studies indicate that overexpression of chemokines, although important in controlling virus infection, may not always be beneficial to the host. collapse abstract

Human metapneumovirus establishes persistent infection in the lungs of mice and is reactivated by glucocorticoid treatment.

Human metapneumovirus (HMPV) has been identified as a worldwide agent of serious upper and lower respiratory tract infections in infants and young children. HMPV is second only to respiratory syncytial virus (RSV) as a leading cause of bronchiolitis,... expand abstract and, like RSV, consists of two major genotypes that cocirculate and vary among communities year to year. Children who have experienced acute HMPV infection may develop sequelae of wheezing and asthma; however, the features contributing to this pathology remain unknown. A possible mechanism for postbronchiolitis disease is that HMPV might persist in the lung providing a stimulus that could contribute to wheezing and asthma. Using immunohistochemistry to identify HMPV-infected cells in the lungs of mice, we show that HMPV mediates biphasic replication in respiratory epithelial cells then infection migrates to neuronal processes that innervate the lungs where the virus persists with no detectable infection in epithelial cells. After glucocorticoid treatment, the virus is reactivated from neural fibers and reinfects epithelial cells. The findings show that HMPV persists in neural fibers and suggest a mechanism for disease chronicity that has important implications for HMPV disease intervention strategies. collapse abstract

Role of chemokines in the enhancement of BBB permeability and inflammatory infiltration after rabies virus infection.

Induction of innate immunity, particularly through the induction of interferon and chemokines, by rabies virus (RABV) infection has been reported to be inversely correlated with pathogenicity. To further investigate the association between the expres... expand abstractsion of chemokines and RABV infection, laboratory-attenuated RABV (B2C) and wild-type (wt) RABV (DRV) were administered to Balb/c mice intramuscularly. Chemokine expression, inflammatory cell infiltration, and blood-brain barrier (BBB) permeability were evaluated at various time points after infection. At day 3 post-infection (p.i.) there was very little inflammation in the central nervous system (CNS) and BBB permeability did not change in mice infected with either virus when compared with mock-infected mice. At 6 day p.i., infection with B2C induced the expression of inflammatory chemokines and infiltration of inflammatory cells into the CNS, while these changes were minimal in DRV-infected mice. Furthermore, infection with B2C significantly enhanced BBB permeability comparing to infection with DRV. Among the upregulated chemokines, the expression of IP-10 was best correlated with infiltration of inflammatory cells into the CNS and enhancement of BBB permeability. These data indicate that laboratory-attenuated RABV induces expression of chemokines and infiltration of inflammatory cells into the CNS. Upregulation of chemokines by B2C may have triggered the change in BBB permeability, which helps infiltration of inflammatory cells into the CNS, and thus attenuation of RABV. collapse abstract

Genetic diversity of Chinese rabies viruses: evidence for the presence of two distinct clades in China.

There have been three major rabies epidemics in China since the 1950s. To gain more insights into the molecular epidemiology of rabies viruses (RVs) for the third (the current) epidemic, we isolated RV from dogs and humans in major endemic areas, and... expand abstract characterized these isolates genetically by sequencing the entire glycoprotein (G) gene and the G-L non-coding region. These sequences were also compared phylogenetically with RVs isolated in China during previous epidemics and those around the world. Comparison of the entire G genes among the Chinese isolates revealed up to 21.8% divergence at the nucleotide level and 17.8% at the amino acid level. The available Chinese isolates could be divided into two distinct clades, each of which could be further divided into six lineages. Viruses in clade I include most of the Chinese viruses as well as viruses from southeast Asian countries including Indonesia, Malaysia, the Philippines, Thailand, and Vietnam. The viruses in the other clade were found infrequently in China, but are closely related to viruses distributed worldwide among terrestrial animals. Interestingly, most of the viruses isolated during the past 10 years belong to lineage A viruses within clade I whereas most of the viruses isolated before 1996 belong to other lineages within clades I and II. Our results indicated that lineages A viruses have been predominant during the past 10 years and thus are largely responsible for the third and the current epidemic in China. Our results also suggested that the Chinese RV isolates in clade I share a common recent ancestor with those circulating in southeast Asia. collapse abstract

The rabies situation in Far East Asia.

This study evaluated rabies epidemiology in Far EastAsia. Questionnaires were sent by the OIE to Far East Asian countries and eight questionnaires were returned. Data were collected from these returns, as well as from recent publications, to gather i... expand abstractnformation regarding rabies epidemiology in these countries. More than 29,000 human deaths were reported in 2006 in Far East Asia, representing more than 50% of all human rabies cases around the globe. There are only a few countries or regions from which no human rabies was reported in 2006 such as Japan, Singapore, South Korea, Malaysia, Hong Kong, and Taiwan. In many of these rabies endemic countries, the number of human rabies cases has not changed much during the past decade. The only country with a steady decline is Thailand, where the number of cases has decreased from around 200 to about 20 cases per year. The most dramatic changes were observed in China. Human rabies cases declined from around 5,000 cases per year in the 1980s to about 160 in the mid-1990s. However, these trends have since been reversed. A steady increase has been reported over the past 10 years with more than 3,200 cases reported in 2006. Although there are many factors that contribute to the epidemic or endemic nature of rabies in these countries, the single most important factor is the failure to immunize domestic dogs, which transmit rabies to humans. Dog vaccination is at or below 5% in many of these countries, and cannot stop the transmission of rabies from dogs to dogs, thus to humans. It is thus most importantforthese countries to initiate mass vaccination campaigns in dog populations in order to stop the occurrence of human rabies in Far East Asia. collapse abstract

Pathogenic rabies virus alters host protein expression in the central nervous system: implications for neuronal dysfunction.

Proteomics technology was employed to profile host responses to rabies virus (RABV) infection in order to understand how RABV infection results in neuronal dysfunction. In mice infected with wild-type (wt) RABV, the expression of proteins involved in... expand abstract ion homeostasis was altered. H+ ATPase and Na+/K+ ATPase were up-regulated while Ca2+ ATPase was downregulated, which resulted in reduction of intracellular Na+ and Ca2+ concentrations. Furthermore, infection with wt RABV resulted in down-regulation of SNAREs such as alpha-SNAP, TRIM9, syntaxin, and pallidin, all of which are involved in docking and fusion of synaptic vesicles to and with the presynaptic membrane. As a consequence, the accumulation of synaptic vesicles was observed in the presynapses of mice infected with wt RABV. These data demonstrate that infection with wt RABV results in the alteration of host protein expression, particularly those involved in ion homeostasis and docking and the fusion of synaptic vesicles to the presynaptic membrane, which may lead to neuronal dysfunction. collapse abstract

Molecular diversity and phylogeny of Hantaan virus in Guizhou, China: evidence for Guizhou as a radiation center of the present Hantaan virus.

To gain further insight into the molecular epidemiology of Hantaan virus (HTNV) in Guizhou, China, rodents were captured in this region in 2004 and 2005. In addition, serum samples were collected from four patients. Ten hantaviruses were isolated suc... expand abstractcessfully in cell culture from four humans, two Apodemus agrarius, three Rattus norvegicus and one Rattus nitidus. The nucleotide sequences for their small (S), medium (M) and partial large (L) segments were determined. Phylogenetic analysis of the S and M segment sequences revealed that all of these isolates belong to the species HTNV, suggesting a spillover of HTNV from A. agrarius to Rattus rats. All available isolates from Guizhou were divided into four distinct groups either in the S segment tree or in the M segment tree. The clustering pattern of these isolates in the S segment tree was not in agreement with that in the M or L segment tree, showing that genetic reassortment between HTNV had occurred naturally. Analysis of the S segment sequences from available HTNV strains indicated that they formed three clades. The first clade, which comprised only viruses from Guizhou, was the outgroup of clades II and III. The viruses in the second clade were found in Guizhou and mainly in the far-east Asian region, including China. However, the viruses in the third clade were found in most areas of China, including Guizhou, in which haemorrhagic fever with renal syndrome (HFRS) is endemic. Our results reveal that the highest genetic diversity of HTNV is in a limited geographical region of Guizhou, and suggest that Guizhou might be a radiation centre of the present form of HTNV. collapse abstract

Rabies in small animals.

Rabies in small animals has been dramatically reduced in the United States since the introduction of rabies vaccination of domestic animals in the 1940s. As a consequence, the number of human rabies cases has declined to only a couple per year. Durin... expand abstractg the past several years, the dog rabies variant has almost disappeared completely. Rabies in wildlife has skyrocketed, however. Each wildlife species carries its own rabies variant(s). These wildlife epizootics present a constant public health threat in addition to the danger of reintroducing rabies to domestic animals. Vaccination is the key to prevent rabies in small animals and rabies transmission to human beings. collapse abstract

Investigation of the role of healthy dogs as potential carriers of rabies virus.

To investigate whether healthy animals are potential carriers of rabies virus in China, 153 domestic dogs were collected from a rabies enzootic area, Anlong county in Guizhou Province, and monitored for 6 months. Initially, findings of rabies virus a... expand abstractntigen in the saliva of 15 dogs by an enzyme-linked immunosorbent assay (ELISA) test suggested they might be carriers. These 15 dogs were kept under observation for 6 months. None of the dogs showed any clinical signs of rabies during the observation period. Moreover, using the ELISA test alone, detection of rabies virus antigen in saliva of some animals was not consistent during the observation period. However, none of the saliva samples collected either at the time of acquisition or during the observation period was found to be positive for rabies virus RNA by reverse transcriptase-polymerase chain reaction (RT-PCR). Furthermore, neither viral antigen nor viral RNA was detected in the brain samples collected at the time of euthanasia. These results do not provide support for the contention that healthy dogs act as carriers in rabies. Caution is urged when preliminary and nondefinitive tests, such as ELISA, are used to infer clinical status related to rabies. collapse abstract

Genetic characterization of hantaviruses isolated from Guizhou, China: evidence for spillover and reassortment in nature.

To gain more insights into the epidemiology of hantaviruses in the Guizhou province, China, rodents were captured in Guizhou during the period from 2001 to 2003. In addition, serum sample was collected from one patient. Virus isolation was attempted ... expand abstractfrom human serum and rodent samples. Four hantaviruses were isolated successfully in cell culture from one human, two A. agrarius, and one R. norvegicus. The nucleotide sequences for the entire S and M and partial L segment were determined from these four isolates as well as six viruses isolated in 1980s. Phylogenetic analysis revealed that the S segment from all isolates belong to the Hantaan virus (HTNV) clade, regardless of the sources from which they were derived. According to the S sequences, these viruses could be divided into three distinct phylogroups, showing geographical clustering. Analysis of the entire M and the partial L segment sequences demonstrated that 8 out of the 10 isolates belong to the HTNV clade. However, two isolates (CGRn8316 and CGRn9415) isolated from R. norvegicus belong to the Seoul virus (SEOV) clade. In addition, these two isolates were distinct from other known members of SEOV clade. Together, the data suggest that at least three groups of HTNV are co-circulating and one new variant of SEOV may be present in Guizhou. Our results also suggest that HTNV from A. agrarius spilled over to R. norvegicus and natural reassortment between HTNV and SEOV occurred during or after the spillover. collapse abstract

Proteomic profiling and neurodegeneration in West-Nile-virus-infected neurons.

West Nile virus, a mosquito-borne flavivirus, is a human, equine, and avian pathogen. High-resolution two-dimensional differential-gel electrophoresis (2D-DIGE) was used to characterize protein expression in primary rat neurons and to examine the pro... expand abstractteomic profiling to understand the pathogenesis of West-Nile-associated meningoencephalitis. Three pH ranges, 3-10, 4-7, and 5-6, were used to analyze the protein spots. The proteins are labeled with fluorescent dyes Cy3 and Cy5 before being separated on the basis of charge and size respectively on a two-dimensional platform. About 55 proteins showed altered expression levels. These were then subsequently digested and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis using peptide mass fingerprinting and database searching. These cellular proteins could represent distinct roles during infection related to apoptosis. Our findings show that two-dimensional differential gel electrophoresis combined with mass spectrometry is a powerful approach that permits the identification of proteins whose expression was altered due to West Nile virus infection. collapse abstract

Detection of phylogenetically distinct Puumala-like viruses from red-grey vole Clethrionomys rufocanus in China.

In order to investigate whether Puumala virus (PUUV) or PUUV-like virus is present in China, Clethrionomys rufocanus and C. rutilus were captured in the Jilin province during the spring and autumn of 2002-2003 for detection of PUUV viral RNA by RT-PC... expand abstractR and confirmation of PUUV-positive antigens by an immunofluorescence assay. PUUV-positive RNA was identified in six out of 121 C. rufocanus but not in any of the 41 C. rutilus. Complete S and partial M sequences (nt 1,316-1,598 and 2,687-3,089) were amplified by RT-PCR directly from some of the antigen positive lung tissues and subjected to nucleic acid sequencing. It was found that the Chinese PUUV-like viruses were related most closely with the PUUV strains with 77.7-81.7% identity at the nucleotide level and 91.7-97% identity at the amino acid level for S segment, and with 77-78.8% identity at the nucleotide level and 91.5-92.6% identity at the amino acid level for the partial M segment (nt 1,316-1,598). Genetic analysis indicated that the Chinese PUUV-like viruses shared the highest level of identity with the viruses which circulate in C. rufocanus in the Far East region of Russia with 85.1-87.4% identity at the nucleotide level and 95.9% identity at the amino acid level for the partial M segment (nt 2,687-3,089), respectively. Phylogenetic analysis revealed that the Chinese PUUV-like viruses are distinct from those identified from Japan, South Korea, Europe or Russia. These results indicate that PUUV-like virus is present in China in addition to Hantaan, Seoul and Dabieshan viruses. collapse abstract

Isolation and characterization of hantavirus carried by Apodemus peninsulae in Jilin, China.

To provide a better understanding of hantavirus epidemiology in China, Korean field mice (Apodemus peninsulae) and striped field mice (Apodemus agrarius) were captured in Jilin province, China, where haemorrhagic fever with renal syndrome (HFRS) is e... expand abstractndemic. Hantavirus antigens were detected in eight of the 130 A. peninsulae individuals and in four of the 193 A. agrarius individuals by using an immunofluorescence assay. Partial S and M segments were amplified from all of the antigen-positive samples. Furthermore, two hantaviruses (CJAp89 and CJAp93) were isolated successfully in cell culture and the entire S and M segments were amplified from one of them (CJAp93). Phylogenetic analysis of these sequences (partial or complete) showed that hantaviruses carried by A. peninsulae and A. agrarius form two distinct lineages, although viruses carried by A. peninsulae are similar to those isolated previously from A. agrarius in China and from HFRS patients in Russia. However, the viruses detected in A. peninsulae in China are genetically different from those detected in A. peninsulae in other countries. These data suggest that A. peninsulae is also a natural host for HTNV in north-eastern China. collapse abstract

Proteomic profiling reveals that rabies virus infection results in differential expression of host proteins involved in ion homeostasis and synaptic physiology in the central nervous system.

To understand how rabies virus (RV) infection results in neuronal dysfunction, the authors employed proteomics technology to profile host responses to RV infection. In mice infected with wild-type (wt) RV, the expression of proteins involved in ion h... expand abstractomeostasis was altered. H(+) ATPase and Na(+)/K(+) ATPase were up-regulated whereas Ca(2+) ATPase was down-regulated, which resulted in reduction of the intracellular Na(+) and Ca(2+) concentrations. Furthermore, infection with wt RV resulted in down-regulation of soluble NSF attachment receptor proteins (SNAREs) such as alpha-synaptosome-associated protein (SNAP), tripartite motif-containing 9 (TRIM9), syntaxin, and pallidin, all of which are involved in docking and fusion of synaptic vesicles to and with presynaptic membrane. As a consequence, accumulation of synaptic vesicles was observed in the presynapses of mice infected with wt RV. These data demonstrate that infection with wt RV results in alteration of host protein expression, particularly those involved in ion homeostasis and docking and fusion of synaptic vesicles to presynaptic membrane, which may lead to neuronal dysfunction. On the other hand, attenuated RV up-regulated the expression of proteins involved in the induction of apoptosis, explaining why apoptosis is observed only in cells or animals infected with attenuated RV in previous studies. collapse abstract

Molecular characterization of rabies virus isolates in China during 2004.

Human rabies cases have been on the rise during the past few years in China and a total of 2651 cases were reported in 2004. To better understand the current rabies epidemics in China, we isolated rabies viruses from dogs and humans from five provinc... expand abstractes and characterized these isolates genetically by sequencing the entire nucleoprotein (N) gene. Comparison of the N genes among these isolates revealed 86.6-99.9% homology and these viruses can be grouped into three lineages. Phylogenetic analysis indicates that all the Chinese isolates have a close relationship with viruses circulating in Asian canine population. When compared with rabies viruses isolated previously, the three lineages were similar to three of the four groups. Thus, our data suggest that rabies viruses currently circulating in China were similar, if not identical, to those reported in the previous epidemics. collapse abstract

Rabies virus-induced apoptosis involves caspase-dependent and caspase-independent pathways.

Previously, it has been shown that the laboratory attenuated rabies virus CVS-B2C, but not the wild-type virus SHBRV, induces apoptosis in mice and the induction of apoptosis is mediated by viral glycoprotein. Induction of apoptosis by CVS-B2C limits... expand abstract the spread of the virus in the CNS. In the present study, we characterized the pathways by which CVS-B2C induces apoptosis. BSR cells were infected with CVS-B2C or SHBRV and harvested at different time points for detection of apoptosis by immunofluorescence and flow cytometry. Apoptosis was detected only in cells infected with CVS-B2C, but not SHBRV. Caspase activity and expression of several apoptotic proteins were analyzed by fluorometric assay and Western blotting. Activation of caspase-8 and -3, but not of caspase-9, was observed in CVS-B2C-infected cells. In addition, the level of expression of Apaf-1 did not change. Furthermore, PARP was cleaved confirming activation of downstream caspases. All these data suggest that CVS-B2C infection activates the extrinsic, but not the intrinsic, apoptotic pathway. In addition, AIF, a caspase-independent apoptotic protein was up-regulated and translocated from the cytoplasm to the nucleus post-infection, suggesting that apoptosis induced by CVS-B2C also involves the activation of a caspase-independent pathway. collapse abstract

Respiratory syncytial virus (RSV) infects neuronal cells and processes that innervate the lung by a process involving RSV G protein.

Respiratory syncytial virus (RSV) is a primary cause of morbidity and life-threatening lower respiratory tract disease in infants and young children. Children with acute RSV bronchiolitis often develop respiratory sequelae, but the disease mechanisms... expand abstract are poorly understood. Mounting evidence suggests that RSV may mediate persistent infection. Using immunohistochemistry to identify RSV and RSV-infected cell types, we show that RSV infects primary neurons and neuronal processes that innervate the lungs through a process that involves RSV G protein and the G protein CX3C motif. These findings suggest a mechanism for disease chronicity and have important implications for RSV disease intervention strategies. collapse abstract

Glycoprotein-mediated induction of apoptosis limits the spread of attenuated rabies viruses in the central nervous system of mice.

Induction of apoptosis by rabies virus (RV) has been reported to be associated with the expression of the glycoprotein (G), but inversely correlated with pathogenicity. To further delineate the association between the expression of the G and the indu... expand abstractction of apoptosis, recombinant RVs with replacement of only the G gene were used to infect mice by the intracerebral route. Recombinant viruses expressing the G from attenuated viruses expressed higher level of the G and induced more apoptosis in mice than recombinant RV expressing the G from wild-type (wt) or pathogenic RV, demonstrating that it is the G gene that determines the level of G expression and, consequently, the induction of apoptosis. Likewise, recombinant viruses expressing the G from wt or pathogenic RV are more pathogenic in mice than those expressing G from attenuated RV, confirming the inverse correlation between RV pathogenicity and the induction of apoptosis. To investigate the mechanism by which induction of apoptosis attenuates viral pathogenicity, mice were infected with wt or attenuated RV by the intramuscular route. It was found that low doses of attenuated RV induced apoptosis in the spinal cord and failed to spread to the brain or produce neurological disease. On the other hand, apoptosis was not observed in the spinal cord of mice infected with the same doses of wt RV and the virus spread to various parts of the brain and induced fatal neurologic disease. These results suggest that glycoprotein-mediated induction of apoptosis limits the spread of attenuated rabies viruses in the central nervous system (CNS) of mice. collapse abstract

Human rabies in China.

Attenuated rabies virus activates, while pathogenic rabies virus evades, the host innate immune responses in the central nervous system.

Rabies virus (RV) induces encephalomyelitis in humans and animals. However, the pathogenic mechanism of rabies is not fully understood. To investigate the host responses to RV infection, we examined and compared the pathology, particularly the inflam... expand abstractmatory responses, and the gene expression profiles in the brains of mice infected with wild-type (wt) virus silver-haired bat RV (SHBRV) or laboratory-adapted virus B2C, using a mouse genomic array (Affymetrix). Extensive inflammatory responses were observed in animals infected with the attenuated RV, but little or no inflammatory responses were found in mice infected with wt RV. Furthermore, attenuated RV induced the expression of the genes involved in the innate immune and antiviral responses, especially those related to the alpha/beta interferon (IFN-alpha/beta) signaling pathways and inflammatory chemokines. For the IFN-alpha/beta signaling pathways, many of the interferon regulatory genes, such as the signal transduction activation transducers and interferon regulatory factors, as well as the effector genes, for example, 2'-5'-oligoadenylate synthetase and myxovirus proteins, are highly induced in mice infected with attenuated RV. However, many of these genes were not up-regulated in mice infected with wt SHBRV. The data obtained by microarray analysis were confirmed by real-time PCR. Together, these data suggest that attenuated RV activates, while pathogenic RV evades, the host innate immune and antiviral responses. collapse abstract

Equine herpesvirus type 1 (EHV-1) infection and vaccination with an inactivated EHV-1 vaccine.

Genetic comparison of the rhabdoviruses from animals and plants.

There are more than 160 viral species in the Rhabdovidae family, most of which can be grouped into one of the six genera including Vesiculovirus, Lyssavirus, Ephemerovirus, Novirhabdovirus, Cytorhabdovirus, and Nucleorhabdovirus. These viruses are no... expand abstractt only morphologically similar but also genetically related. Analysis of viral genes shows that rhabdoviruses are more closely related to each other than to viruses in other families. With the development of reverse genetics, the functions of many cis- and trans-elements important in the process of viral transcription and replication have been clearly defined such as the leader, trailer, and the intergenic sequences. Furthermore, it has been shown that there are two entry sites for the RNA-dependent RNA polymerase: 3' entry for leader synthesis and RNA replication, and direct entry at the N gene start sequence for transcription of the monocistronic mRNAs. collapse abstract

New frontiers in proteomics research: a perspective.

Substantial advances have been made in the fundamental understanding of human biology, ranging from DNA structure to identification of diseases associated with genetic abnormalities. Genome sequence information is becoming available in unprecedented ... expand abstractamounts. The absence of a direct functional correlation between gene transcripts and their corresponding proteins, however, represents a significant roadblock for improving the efficiency of biological discoveries. The success of proteomics depends on the ability to identify and analyze protein products in a cell or tissue and, this is reliant on the application of several key technologies. Proteomics is in its exponential growth phase. Two-dimensional electrophoresis complemented with mass spectrometry provides a global view of the state of the proteins from the sample. Proteins identification is a requirement to understand their functional diversity. Subtle difference in protein structure and function can contribute to complexity and diversity of life. This review focuses on the progress and the applications of proteomics science with special reference to integration of the evolving technologies involved to address biological questions. collapse abstract

Degeneration of neuronal processes after infection with pathogenic, but not attenuated, rabies viruses.

The structural alterations of neuronal processes in mice were investigated after the mice were infected with rabies virus (RV). Silver staining of infected brain sections showed severe destruction and disorganization of neuronal processes in mice inf... expand abstractected with pathogenic RV but not with attenuated RV. However, neuronal bodies showed very little pathological changes. Electron microscopy revealed the disappearance of intracellular organelles, as well as the disappearance of synaptic structures and vesicles. Infection of primary neurons with pathogenic, but not attenuated, RV resulted in the destruction of neuronal processes and disappearance of microtubule-associated protein 2 and neurofilament immunoreactivity, which suggests that pathogenic RV causes degeneration of neuronal processes possibly by interrupting cytoskeletal integrity. collapse abstract