- Volume 91, Issue 3, 2010
Volume 91, Issue 3, 2010
- Animal
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- DNA viruses
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Characterization of novel polyomaviruses from Bornean and Sumatran orang-utans
Serological screening of sera from orang-utans demonstrated a high percentage of sera that cross-reacted with antigens of the polyomavirus (PyV) simian virus 40. Analysis of archival DNA samples from 71 Bornean and eight Sumatran orang-utans with a broad-spectrum PCR assay resulted in the detection of PyV infections in 11 animals from both species. Sequence analysis of the amplicons revealed considerable differences between the PyVs from Bornean and Sumatran orang-utans. The genome from two PyVs, one from each species, was therefore amplified and sequenced. Both viral genomes revealed a characteristic PyV architecture, but lacked an obvious agnogene. Neighbour-joining analysis positioned the viruses in a large cluster together with viruses from bats, bovines, rodents and several primate PyVs from chimpanzees, African green monkeys, squirrel monkeys and the human Merkel cell PyV.
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Identification of protein–protein interactions of the occlusion-derived virus-associated proteins of Helicoverpa armigera nucleopolyhedrovirus
More LessThe purpose of this study was to identify protein–protein interactions among the components of the occlusion-derived virus (ODV) of Helicoverpa armigera nucleopolyhedrovirus (HearNPV), a group II alphabaculovirus in the family Baculoviridae. To achieve this, 39 selected genes of potential ODV structural proteins were cloned and expressed in the Gal4 yeast two-hybrid (Y2H) system. The direct-cross Y2H assays identified 22 interactions comprising 13 binary interactions [HA9–ODV-EC43, ODV-E56–38K, ODV-E56–PIF3, LEF3–helicase, LEF3–alkaline nuclease (AN), GP41–38K, GP41–HA90, 38K–PIF3, 38K–PIF2, VP80–HA100, ODV-E66–PIF3, ODV-E66–PIF2 and PIF3–PIF2] and nine self-associations (IE1, HA44, LEF3, HA66, GP41, CG30, 38K, PIF3 and P24). Five of these interactions – LEF3–helicase and LEF3–AN, and the self-associations of IE1, LEF3 and 38K – have been reported previously in Autographa californica multiple nucleopolyhedrovirus. As HA44 and HA100 were two newly identified ODV proteins of group II viruses, their interactions were further confirmed. The self-association of HA44 was verified with a His pull-down assay and the interaction of VP80–HA100 was confirmed by a co-immunoprecipitation assay. A summary of the protein–protein interactions of baculoviruses reported so far, comprising 68 interactions with 45 viral proteins and five host proteins, is presented, which will facilitate our understanding of the molecular mechanisms of baculovirus infection.
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- Plant
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Structural homology between bamboo mosaic virus and its satellite RNAs in the 5′untranslated region
More LessA structural element was identified in the 5′-proximal sequence of the bamboo mosaic virus (BaMV) RNA. Mutational analysis of the hairpin showed that disruptions of the secondary structure or substitutions of the loop sequences resulted in reduced accumulation of BaMV genomic RNA. Phylogenetic analysis further suggested the presence of structural homologues of this hairpin in all other potexviruses. In addition, remarkable structural homology was discovered between the BaMV hairpin and a stem–loop in the 5′untranslated region of satellite RNAs responsible for attenuation of BaMV in co-infected plants. The role of this homology in the helper–satellite interaction is discussed.
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Evolutionary trajectory of turnip mosaic virus populations adapting to a new host
More LessLittle is known about how some plant viruses establish successful cross-species transmission whilst others do not; the genetic basis for adaptation is largely unknown. This study investigated the genetic changes that occurred using the progeny of an infectious clone, p35Tunos, derived from the turnip mosaic virus (TuMV) UK 1 isolate, which has a Brassica host type, but rarely infects Raphanus systemically and then only asymptomatically. The genetic trajectory leading to viral adaptation was studied in a TuMV isolate passaged in Nicotiana benthamiana (parental), Brassica rapa, the old (susceptible) host and Raphanus sativus, the new (almost insusceptible) host. Almost-complete consensus genomic sequences were obtained by RT-PCR of viral populations passaged up to 35 times together with 59 full sequences of 578 200 nt. There were significant differences in the nucleotide and encoded amino acid changes in the consensus genomes from the old and new hosts. Furthermore, a 3264 nt region corresponding to nt 3222–6485 of the UK 1 genome was cloned, and 269 clones from 23 populations were sequenced; this region covered 33 % of the genome and represented a total of 878 016 nt. The results showed that the nucleotide diversity and the non-synonymous/synonymous ratio of the populations from the new host were higher than those from the old host. An analysis of molecular variance showed significant differences among the populations from the old and new hosts. As far as is known, this is the first report comparing the evolutionary trajectory dynamics of plant virus populations in old and new hosts.
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Transcriptomic analysis of intestinal genes following acquisition of pea enation mosaic virus by the pea aphid Acyrthosiphon pisum
Viruses in the family Luteoviridae are strictly transmitted by aphids in a non-propagative, circulative and persistent mode. Virions ingested by aphids successively cross the gut and the accessory salivary gland epithelia before being released, together with saliva, into the plant vasculature. Virion transport through aphid cells occurs by a transcytosis mechanism. This study conducted a transcriptomic analysis of intestinal genes of the pea aphid Acyrthosiphon pisum following uptake of pea enation mosaic virus. Among the 7166 transcripts analysed, 128 were significantly regulated (105 genes downregulated and 23 upregulated). Of these genes, 5 % were involved in intracellular trafficking, endocytosis and signal transduction, three important steps in the internalization and transport of virions. The limited levels of downregulation (maximum of 3.45-fold) and upregulation (maximum of 1.37-fold) suggest that the virus hijacks a constitutive endocytosis–exocytosis mechanism without heavily perturbing cell metabolism. Although limited to about 20 % of the pea aphid genes, this work represents the first large-scale analysis of aphid gene regulation following virus acquisition. A better knowledge of this virus–vector interaction will be possible only when tools representing the complete genomic capacity of the aphid become available.
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- Other Agents
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Mouse vaccination with dendritic cells loaded with prion protein peptides overcomes tolerance and delays scrapie
Prion diseases are presumed to be caused by the accumulation in the brain of a pathological protein called prion protein (PrP) scrapie which results from the transconformation of cellular PrP, a ubiquitous glycoprotein expressed in all mammals. Since all isoforms of PrP are perceived as self by the host immune system, a major problem in designing efficient immunoprophylaxis or immunotherapy is to overcome tolerance. The present study was aimed at investigating whether bone-marrow-derived dendritic cells (DCs) loaded with peptides previously shown to be immunogenic in PrP-deficient mice, can overcome tolerance in PrP-proficient wild-type mice and protect them against scrapie. Results show that, in such mice, peptide-loaded DCs elicit both lymphokine release by T cells and antibody secretion against native cellular PrP. Repeated recalls with peptide-loaded DCs reduces the attack rate of 139A scrapie inoculated intraperitoneally and retards disease duration by 40 days. Most interestingly, survival time in individual mice appears to be correlated with the level of circulating antibody against native cellular PrP.
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Volumes and issues
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Volume 105 (2024)
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Volume 35 (1977)
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Volume 8 (1970)
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Volume 7 (1970)
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Volume 6 (1970)
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Volume 5 (1969)
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Volume 4 (1969)
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Volume 3 (1968)
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Volume 2 (1968)
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Volume 1 (1967)