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PubMed1992

Tobamovirus-plant interactions.

It is clear that the genetic information responsible for the phenomenon we think of as TMV not only consists of the genes carried in the viral genome, but that numerous plant genes are equally important in viral gene functions. These gene products not only allow the virus to replicate, but may effect functions of evolution that determine what the virus is. Even the processes of pathogenesis and resistance appear to involve similarly precise plant interactions. The challenge of the future is to identify the plant genes involved in these precise interactions and to understand both components of genetic information that comprise plant viruses.

Biological Evolution↗
PubMed2005

Evolution in the hypervariable region of the hepatitis C virus in two infants infected by mother-to-infant transmission.

BACKGROUND: There is little data on the evolution of hepatitis C virus (HCV) quasispecies in infants infected by mother-to-infant transmission during long-term follow up. The hypervariable region 1 (HVR1) of the HCV genome was investigated in two mother-infant pairs from birth to 7.6 and 10.2 years, respectively. METHODS: Ten cDNA clones of HVR1 generated from HCV-RNA and extracted from serum samples of both pairs were analyzed. The sequences were compared with regard to variability, identity, and hydrophobia profile, and analyzed by phylogenetic studies. RESULTS: The alanine aminotransferase (ALT) level was high with fluctuation in infant A and almost within the normal range in infant B. Sequence diversity was higher in infant A at 7.6 years than in infant B at 9.3 years (sequence identity with the mothers'; 69.3-70.7% vs 85.3-90.7% for nucleotides, and 48% vs 68-72% for amino acids, respectively). Compared to the first samples, amino acid changes greatly increased in infant A (35.2% at 4.9 years and 52% at 7.6 years), but not in infant B (4% at 5.6 years and 27.5% at 9.3 years). Phylogenetic studies revealed that quasispecies in infant A evolved to a greater extent than that in infant B. Hydrophobia profile analyses revealed that dynamic shifts between hydrophilia and hydrophobia occurred in both infants. CONCLUSIONS: As in adults, the evolution of HVR1 and variability of quasispecies increased in infants infected through mother-to-infant transmission for 10 years after birth. A large episode of ALT elevation suggested the emergence of escape mutants and the evolution of new quasispecies.

Alanine Transaminase↗
PubMed1994

Evolution and selection of hepatitis C virus variants in patients with chronic hepatitis C.

It has been shown that hepatitis C virus (HCV) populations in vivo are composed of different but highly homologous HCV genomes (quasispecies) as shown in the hypervariable region (HVR) that exists in the N-terminal of the envelope 2 gene of HCV, and that the predominant sequence of the HVR of HCV genomes changes rapidly over time. To further investigate genetic backgrounds of the change in the HVR of HCV genomes, 45 plasma samples serially obtained from nine patients with chronic hepatitis C were studied using population-based analyses. Total RNA was recovered and the envelope gene containing the HVR was amplified by the reverse transcription and nested polymerase chain reaction. The amplified cDNA was examined by the single strand conformation polymorphism (SSCP) analysis. Furthermore, 43 HCV sequences, separated by the SSCP analysis from three patients were determined by the dideoxy chain termination method, and the phylogenetic analysis was performed using the neighbor joining method. The SSCP analysis demonstrated that HCV population within each individual were composed of 1 to 6 quasispecies. These quasispecies populations in vivo changed sequentially in eight of nine patients. Gradual selections of coexisting quasispecies were observed over 6- to 18-month periods in three patients, whereas complete replacements of previous quasispecies by new quasispecies were repeatedly observed over few-month intervals in five patients. The phylogenetic analysis on these quasispecies revealed the continuous accumulation of mutations in two patients and discontinuous appearance of evolutionarily distant quasispecies in one patient. These results indicate that HCV genomes in vivo form quasispecies populations, and that these quasispecies populations change during the natural course of chronic infection. Genetic mechanisms underlining the change of the HVR of HCV genome appear to be either continuous accumulation of mutations or selective overgrowth of preexisting minor variants from the large spectrum of quasispecies populations.

Aged↗
PubMed1994

Evolutionary pattern of human respiratory syncytial virus (subgroup A): cocirculating lineages and correlation of genetic and antigenic changes in the G glycoprotein.

The genetic and antigenic variability of the G glycoproteins from 76 human respiratory syncytial (RS) viruses (subgroup A) isolated during six consecutive epidemics in either Montevideo, Uruguay, or Madrid, Spain, have been analyzed. Genetic diversity was evaluated for all viruses by the RNase A mismatch cleavage method and for selected strains by dideoxy sequencing. The sequences reported here were added to those published for six isolates from Birmingham, United Kingdom, and for two reference strains (A2 and Long), to derive a phylogenetic tree of subgroup A viruses that contained two main branches and several subbranches. During the same epidemic, viruses from different branches were isolated. In addition, closely related viruses were isolated in distant places and in different years. These results illustrate the capacity of the virus to spread worldwide, influencing its mode of evolution. The antigenic analysis of all isolates was carried out with a panel of anti-G monoclonal antibodies that recognized strain-specific (or variable) epitopes. A close correlation between genetic relatedness and antigenic relatedness in the G protein was observed. These results, together with an accumulation of amino acid changes in a major antigenic area of the G glycoprotein, suggest that immune selection may be a factor influencing the generation of RS virus diversity. The pattern of RS virus evolution is thus similar to that described for influenza type B viruses, expect that the level of genetic divergence among the G glycoproteins of RS virus isolates is the highest reported for an RNA virus gene product.

Amino Acid Sequence↗
PubMed1985

Influence of cellular functions on the evolution of persistent infections with Junin virus.

Vero cell cultures persistently infected with Junin virus and subjected to different cultural conditions were established. The production of infectious plaque-forming virus, ts mutants and interfering viral particles was determined at different times during 110 days after infection. Carrier cultures maintained in stationary conditions continuously released PFU while proliferating persistent cultures exhibited a cyclical pattern which tends to a rapid PFU disappearance. Concomitantly, in stationary cultures the production of interfering particles was delayed and was lower than in actively growing persistent cells. The metabolic state of the infected cells did not affect the release of ts mutants. The results suggest that a cellular function is involved on the regulation of Junin virus persistent infections.

Animals↗
PubMed2005

Oryctes virus--time for a new look at a useful biocontrol agent.

The introduction of Oryctes virus into outbreak areas of the rhinoceros beetle, Oryctes rhinoceros (Coleoptera: Scarabaeidae), has been a major success for "classical" biocontrol with a virus and has led to a dramatic reduction in palm damage in many areas of the Asia/Pacific region. In recent years, however, there have been new reports of high levels of rhinoceros beetle damage to palms. Damage has been especially intense in SE Asia following the introduction of no-burn polices for land clearance and replanting, but outbreaks have also been reported from some Pacific Islands where control seems to have diminished over time. SE Asian studies show that there is considerable genetic variation among endemic Oryctes virus isolates and studies in new island release areas have shown rapid evolution of the virus. The consequences of such genetic variation are in need of further study. Furthermore, the taxonomic position of the virus is unclear, with its removal from the Baculoviridae to an "unassigned' virus, reflecting its novel characteristics. Genomic sequencing could help resolve the taxonomy of the virus and provide a basis for studying strain variation. Oryctes virus has achieved wide success in the past without the benefit of molecular analysis and identification techniques. In order to fully take advantage of this unique pathogen for protection of palms, a renewed, coordinated effort centered on genetic selection and distribution of effective strains is required.

Animals↗
PubMed1999

CTL granules: evolution of vesicles essential for combating virus infections.

Viral strategies for escaping apoptosis have co-evolved with the immune system, resulting in a complex balance of pro- and anti-apoptotic forces in virus-infected cells under attack by cytotoxic T lymphocytes (CTLs). Here, Joseph Trapani and colleagues argue that CTL cytolytic granules are the principal apoptotic means of eliminating viruses and possess multiple independent mechanisms to counter the viral anti-apoptotic machinery.

Animals↗
PubMed1977

Evolution of primate oncornaviruses: An endogenous virus from langurs (Presbytis spp.) with related virogene sequences in other Old World monkeys.

Gene sequences related to a retrovirus (oncornavirus type D) isolated from a lung cell culture from spectacled langur (Presbytis obscurus) are found in multiple copies (20-40 per haploid genome) in langur cellular DNA; partially homologous virogene sequences are present in the DNA of related Old World monkey species. Primates thus contain gene sequences for at least two distinct classes of genetically transmitted oncornaviruses, the type C class (isolated from baboons) and the type D class described here. The langur virus is partially related to Mason-Pfizer monkey virus, a type D retrovirus isolated from rhesus monkeys. Nucleic acid hybridization studies suggest that Mason-Pfizer monkey virus, now infectious among primates, was derived from an endogenous virus of langurs or from another member of the primate sub-family Colobinae.

Journal Article↗
PubMed1982

Evolution of influenza A and B viruses: conservation of structural features in the hemagglutinin genes.

The complete nucleotide sequence of the hemagglutinin (HA) gene of a type B influenza virus (B/Lee/40) was obtained by using cloned cDNA derived from the RNA segment. The gene is 1,882 nucleotides long and can code for a protein precursor of 584 amino acids. Structural features common to type A virus HAs are also conserved in the B virus HA. These include a hydrophobic signal peptide, hydrophobic NH2 and COOH termini of the HA2 subunit, and a HA1/HA2 cleavage site involving an arginine residue. The sequence of the B HA gene and its deduced amino acid sequence were compared to those of a type A influenza virus (A/PR/8/34). When these two genes were aligned, it was found that 24% of the amino acids in the HA1 subunits and 39% of the amino acids in the HA2 subunits are conserved. This degree of relatedness between type B virus and type A virus HAs (intertypic comparison) is similar to the homologies observed among certain type A virus HAs (intratypic comparison). A close evolutionary relationship is therefore suggested between the HAs of type A and type B influenza viruses.

Amino Acid Sequence↗
PubMed2001

Evolution of coinfection with human immunodeficiency virus and hepatitis C virus in patients treated with highly active antiretroviral therapy.

A retrospective analysis of data from a cohort of patients coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) who were treated with highly active antiretroviral therapy (HAART) at 3 infectious diseases units in northern Italy was performed. While the patients were receiving HAART, CD4(+) cell counts significantly increased and HIV RNA serum levels decreased. However, no significant overall changes in alanine aminotransferase (ALT) levels and HCV RNA serum levels were observed. Fifteen (4.6%) of 323 patients died within 3 years of follow-up; death was related to cirrhosis in 5 patients (1.6%). No significant difference was observed between cirrhosis-related mortality and mortality related to other causes. Patients with ALT levels >4 times the normal values at initiation of HAART showed a significant decrease in ALT levels, whereas patients with normal ALT levels at initiation of HAART showed a significant increase over time, suggesting that HAART may have long-term beneficial or detrimental effects, depending on patient characteristics.

Alanine Transaminase↗
PubMed2004

Studies of genetically defined chimeras of a European type A virus and a South African Territories type 2 virus reveal growth determinants for foot-and-mouth disease virus.

The three South African Territories (SAT) types of foot-and-mouth disease virus (FMDV) display great genetic and antigenic diversity, resulting from the independent evolution of these viruses in different geographical localities. For effective control of the disease in such areas, the use of custom-made vaccines is required. To circumvent the tedious process of vaccine strain selection, an alternative in the control process is being investigated. Specifically, it is proposed to replace the antigenic determinants of an infectious genome-length cDNA copy of a good SAT vaccine strain with those of appropriate field strains, producing custom-made FMDV chimeras for use in vaccine production. Here the construction of an infectious genome-length cDNA copy of the SAT2 vaccine strain, ZIM/7/83, is described, created utilizing an exchange-cassette strategy with an existing A(12) genome-length cDNA clone. The virus derived from this cDNA (designated vSAT2) displayed excellent growth properties in cell culture, indicating its potential usefulness in the production of custom-made vaccine strains. Evaluation of the growth of various SAT2/A12 chimeras created during the derivation of SAT2 infectious cDNA suggested incompatibilities between the non-structural proteins of ZIM/7/83 and the 5' UTR of A(12).

Animals↗
PubMed2006

Characterization of the archaeal thermophile Sulfolobus turreted icosahedral virus validates an evolutionary link among double-stranded DNA viruses from all domains of life.

Icosahedral nontailed double-stranded DNA (dsDNA) viruses are present in all three domains of life, leading to speculation about a common viral ancestor that predates the divergence of Eukarya, Bacteria, and Archaea. This suggestion is supported by the shared general architecture of this group of viruses and the common fold of their major capsid protein. However, limited information on the diversity and replication of archaeal viruses, in general, has hampered further analysis. Sulfolobus turreted icosahedral virus (STIV), isolated from a hot spring in Yellowstone National Park, was the first icosahedral virus with an archaeal host to be described. Here we present a detailed characterization of the components forming this unusual virus. Using a proteomics-based approach, we identified nine viral and two host proteins from purified STIV particles. Interestingly, one of the viral proteins originates from a reading frame lacking a consensus start site. The major capsid protein (B345) was found to be glycosylated, implying a strong similarity to proteins from other dsDNA viruses. Sequence analysis and structural predication of virion-associated viral proteins suggest that they may have roles in DNA packaging, penton formation, and protein-protein interaction. The presence of an internal lipid layer containing acidic tetraether lipids has also been confirmed. The previously presented structural models in conjunction with the protein, lipid, and carbohydrate information reported here reveal that STIV is strikingly similar to viruses associated with the Bacteria and Eukarya domains of life, further strengthening the hypothesis for a common ancestor of this group of dsDNA viruses from all domains of life.

Amino Acid Sequence↗
PubMedDate not supplied

[Temporal evolution of tuberculosis and human immunodeficiency virus infection in a population cared for in a hospital in Málaga].

BACKGROUND: We have studied the incidence of tuberculosis++ disease, HIV infection and their association during a period of 6 years using samples analysed in a third level hospital laboratory. MATERIAL AND METHOD: 21,242 samples for mycobacteria and 63,425 for HIV antibodies were analysed between 1993 and 1998. The protocol used for mycobacteria consisted of Lowenstein-Jensen, hemoculture, biochemical tests for identification and DNA probe. The diagnosis of HIV was performed using screening with mix EIA HIV 1 + 2, confirmed with Western-blot. Spearman coefficient correlation was used for study of tendency. RESULTS: 1,613 samples (7.5%) positive for mycobacteria from 566 patients (98 females and 428 males) aging between 31 and 40 years (46.9%) were detected. The highest incidence for tuberculosis was observed in 1995 (49.2 x 10(5) and was followed by a decreasing linear tendency. Mycobacterium tuberculosis (96%) and M. bovis (2.7%) were most frequent agents. 2,295 samples (3.6%) showed anti-HIV (406 females and 1,889 males). 54.1% of the infected patients belonged to the age interval 21 to 40 years. The highest incidence was observed in 1994 and was followed by a significant decrease (p < 0.05). The percentage of patients co-infected with tuberculosis-HIV was 39.7% with a maximum in 1995 followed by a linear decrease. CONCLUSIONS: The incidence of both infections and co-infection was very high in the first triennium and was followed by a progressive decrease. The decrease of HIV preceded tuberculosis. The result suggest a possible epidemiological correlation between both infections.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

[Combined experimental infection of Microtus gregalis by tick-borne encephalitis and rabies viruses and probable interference].

Narrow-skulled voles (Microtus gregalis) were inoculated with tick-borne encephalitis (TBE) and rabies (RV) viruses isolated in the steppe zone of West Siberia. TBE infection was asymptomatic and nonlethal in all voles. The virus was eliminated from the voles between days 14 and 60 postinoculation. Only 1 of 26 tested animals produced anti-TBE antibodies in titer 1:20. RV infection was acute and lethal. All sick animals contained RV in the brain, 42.1% in salivary glands, 5.3% in the lungs and kidneys. The voles which survived RV inoculation had no RV. The voles inoculated with RV after TBE were less sensitive and had a longer incubation period in comparison with the animals challenged with RV alone. The differences augmented from day 0 to day 14 after TBE inoculation and became statistically significant on day 14. Later, 21 day after challenge with TBE virus, the differences almost disappeared. The role of possible interference in the evolution of virus-host interaction of Lyssaviruses is discussed.

Animals↗