Biomedical subjects

Balázs Harrach

Publications and source records attributed to Balázs Harrach.

11 recordsLinked to original sources

PubMed2005

Complete genome sequence of simian adenovirus 1: an Old World monkey adenovirus with two fiber genes.

Simian adenovirus 1 (SAdV-1) is one of many adenovirus strains that were isolated from Old World monkey cells during poliomyelitis vaccine production several decades ago. Despite the availability of these viruses, knowledge of their genetic content and phylogeny is rudimentary. In the present study, the genome sequence of SAdV-1 (34,450 bp) was determined and analysed. In regions where genetic content varies between primate adenoviruses, SAdV-1 has a single virus-associated RNA gene, six genes in each of the E3 and E4 regions and two fiber genes. SAdV-1 clusters phylogenetically with HAdV-40, a member of human adenovirus species HAdV-F, which also has two fiber genes. However, based on phylogenetic distances and other taxonomic criteria, SAdV-1 is proposed to represent a novel adenovirus species.

Adenoviruses, Simian↗

PubMed2004

A parvovirus isolated from royal python (Python regius) is a member of the genus Dependovirus.

Parvoviruses were isolated from Python regius and Boa constrictor snakes and propagated in viper heart (VH-2) and iguana heart (IgH-2) cells. The full-length genome of a snake parvovirus was cloned and both strands were sequenced. The organization of the 4432-nt-long genome was found to be typical of parvoviruses. This genome was flanked by inverted terminal repeats (ITRs) of 154 nt, containing 122 nt terminal hairpins and contained two large open reading frames, encoding the non-structural and structural proteins. Genes of this new parvovirus were most similar to those from waterfowl parvoviruses and from adeno-associated viruses (AAVs), albeit to a relatively low degree and with some organizational differences. The structure of its ITRs also closely resembled those of AAVs. Based on these data, we propose to classify this virus, the first serpentine parvovirus to be identified, as serpentine adeno-associated virus (SAAV) in the genus Dependovirus.

Amino Acid Sequence↗

PubMed2004

DNA sequencing and analysis of the right-hand part of the genome of the unique bovine adenovirus type 10.

The prototype strain of bovine adenovirus (BAdV) type 10 and four additional isolates that were indistinguishable in serum-neutralization tests have been shown to have remarkable variation in their genome size and restriction maps. In the present study, more than 40 % of the DNA sequence of the BAdV-10 isolate with the longest genome was determined. A biased base composition resulting in low (<41 %) GC content was noticed. Analysis of the genes of the DNA-binding protein, 100K, 33K, pVIII and fibre proteins, as well as early regions E3 and E4, which are encoded by the genome fragment examined, confirmed that BAdV-10 is different from the other known BAdV types regarding its phylogenetic distance and the organization of its exceptionally short E3 region, apparently containing only two genes. A comparative analysis of the E3 and E4 regions of BAdV-10 with various animal adenoviruses revealed interesting features accounting for the very short genome of BAdV-10. In the examined BAdV-10 isolate, duplicated sequences were localized in and around the fibre gene. Since BAdV-10 appears to be pathogenic to cattle and is genetically distant from the other BAdVs, we suggest that BAdV-10 is not a genuine bovine virus, but has recently switched host and is now undergoing an adaptation process in its new host. In accordance with this hypothesis, the remarkable predominance of AT-rich codons along with the variable fibre gene might be signs of adaptation.

Amino Acid Sequence↗

PubMed2004

Analysis of the first complete genome sequence of an Old World monkey adenovirus reveals a lineage distinct from the six human adenovirus species.

Simian adenovirus 3 (SAdV-3) is one of several adenoviruses that were isolated decades ago from Old World monkeys. Determination of the complete DNA sequence of SAdV-3 permitted the first full genomic comparison of a monkey adenovirus with adenoviruses of humans (HAdVs) and chimpanzees, which are recognized formally as constituting six of the species (HAdV-A to HAdV-F) within the genus Mastadenovirus. The SAdV-3 genome is 34 246 bp in size and has a G+C content of 55.3 mol%. It contains all the genes that are characteristic of the genus Mastadenovirus and has a single VA-RNA gene and six genes in each of the E3 and E4 regions. The genetic organization is the same as that of HAdV-12, a member of the HAdV-A species. Phylogenetic analyses showed that although SAdV-3 is related marginally more closely to HAdV-A and HAdV-F than to other species, it represents a unique lineage that branched at an early stage of primate adenovirus divergence. The results imply that the genetic layout in SAdV-3 and HAdV-12 may also have characterized the common ancestor of all sequenced primate adenoviruses.

Adenoviruses, Simian↗

PubMed2004

Detection and analysis of six lizard adenoviruses by consensus primer PCR provides further evidence of a reptilian origin for the atadenoviruses.

A consensus nested-PCR method was designed for investigation of the DNA polymerase gene of adenoviruses. Gene fragments were amplified and sequenced from six novel adenoviruses from seven lizard species, including four species from which adenoviruses had not previously been reported. Host species included Gila monster, leopard gecko, fat-tail gecko, blue-tongued skink, Tokay gecko, bearded dragon, and mountain chameleon. This is the first sequence information from lizard adenoviruses. Phylogenetic analysis indicated that these viruses belong to the genus Atadenovirus, supporting the reptilian origin of atadenoviruses. This PCR method may be useful for obtaining templates for initial sequencing of novel adenoviruses.

Amino Acid Sequence↗

PubMed2003

Genetic content and evolution of adenoviruses.

This review provides an update of the genetic content, phylogeny and evolution of the family Adenoviridae. An appraisal of the condition of adenovirus genomics highlights the need to ensure that public sequence information is interpreted accurately. To this end, all complete genome sequences available have been reannotated. Adenoviruses fall into four recognized genera, plus possibly a fifth, which have apparently evolved with their vertebrate hosts, but have also engaged in a number of interspecies transmission events. Genes inherited by all modern adenoviruses from their common ancestor are located centrally in the genome and are involved in replication and packaging of viral DNA and formation and structure of the virion. Additional niche-specific genes have accumulated in each lineage, mostly near the genome termini. Capture and duplication of genes in the setting of a 'leader-exon structure', which results from widespread use of splicing, appear to have been central to adenovirus evolution. The antiquity of the pre-vertebrate lineages that ultimately gave rise to the Adenoviridae is illustrated by morphological similarities between adenoviruses and bacteriophages, and by use of a protein-primed DNA replication strategy by adenoviruses, certain bacteria and bacteriophages, and linear plasmids of fungi and plants.

Adenoviridae↗

PubMed2002

Molecular confirmation of an adenovirus in brushtail possums (Trichosurus vulpecula).

Partial genome characterisation of a non-cultivable marsupial adenovirus is described. Adenovirus-like particles were found by electron microscopy (EM) in the intestinal contents of brushtail possums (Trichosurus vulpecula) in New Zealand. Using degenerate PCR primers complementary to the most conserved genome regions of adenoviruses, the complete nucleotide sequence of the penton base gene, and partial nucleotide sequences of the DNA polymerase, hexon, and pVII genes were obtained. Phylogenetic analysis of the penton base gene strongly suggested that the brushtail possum adenovirus (candidate PoAdV-1) belongs to the recently proposed genus Atadenovirus. Sequence analysis of the PCR products amplified from the intestinal contents of brushtail possums originating from different geographical regions of New Zealand identified a single genotype. This is the first report of molecular confirmation of an adenovirus in a marsupial.

Adenoviridae Infections↗

PubMed2002

Genomic and phylogenetic analyses of an adenovirus isolated from a corn snake (Elaphe guttata) imply a common origin with members of the proposed new genus Atadenovirus.

Approximately 60% of the genome of an adenovirus isolated from a corn snake (Elaphe guttata) was cloned and sequenced. The results of homology searches showed that the genes of the corn snake adenovirus (SnAdV-1) were closest to their counterparts in members of the recently proposed new genus ATADENOVIRUS: In phylogenetic analyses of the complete hexon and protease genes, SnAdV-1 indeed clustered together with the atadenoviruses. The characteristic features in the genome organization of SnAdV-1 included the presence of a gene homologous to that for protein p32K, the lack of structural proteins V and IX and the absence of homologues of the E1A and E3 regions. These characteristics are in accordance with the genus-defining markers of atadenoviruses. Comparison of the cleavage sites of the viral protease in core protein pVII also confirmed SnAdV-1 as a candidate member of the genus ATADENOVIRUS: Thus, the hypothesis on the possible reptilian origin of atadenoviruses (Harrach, Acta Veterinaria Hungarica 48, 484-490, 2000) seems to be supported. However, the base composition of DNA sequence (>18 kb) determined from the SnAdV-1 genome showed an equilibrated GC content of 51%, which is unusual for an atadenovirus.

Adenoviridae↗

PubMed2002

First molecular evidence for the existence of distinct fish and snake adenoviruses.

From adenovirus-like viruses originating from a fish and a snake species, a conserved part of the adenoviral DNA polymerase gene was PCR amplified, cloned and sequenced. Phylogenetic analysis showed that the snake adenovirus is closely related to the members of the proposed genus Atadenovirus, whereas the fish isolate seems to represent a separate cluster, likely a new genus.

Adenoviridae↗

PubMed2002

Sequence analysis of old and new strains of porcine circovirus associated with congenital tremors in pigs and their comparison with strains involved with postweaning multisystemic wasting syndrome.

The entire genomes of 7 isolates of porcine circovirus (PCV) from pigs with congenital tremors (CT), type A2, or postweaning multisystemic wasting syndrome (PMWS) were cloned and sequenced. One isolate (CT-PCV-P7) originated from the late 1960s from a neonatal pig with CT, type A2. Two recent PCV isolates (CT-PCV-P5, CT-PCV-P6) were from 2 affected neonatal pigs, from different farms, with unrelated outbreaks of CT; type A2. Four isolates (PMWS-PCV-P1, PMWS-PCV-P2, PMWS-PCV-P3, PMWS-PCV-P4) originated from pigs with PMWS from 4 different farms. A comparative analysis of these PMWS and PCV isolates demonstrated 99% sequence identity with each other, and over 96% sequence identity with previously sequenced PCV2 isolates. The CT-PCV-P5 and CT-PCV-P6 isolates, however, shared 99% of the same identity with each other, and interestingly also with PMWS PCV isolates. There were no consistent genomic differences between PMWS and recent CT isolates. The CT-PCV-P7 showed 98% identity similarity to PK-15-derived PCV1 and demonstrated only 72% identity similarity to either CT-PCV-P5 or CT-PCV-P6. Phylogenetic analysis confirmed that the old isolate (CT-PCV-P7), and the new isolates (CT-PCV-P5, CT-PCV-P6, PMWS-PCV-P1, PMWS-PCV-P2, PMWS-PCV-P3, PMWS-PCV-P4) were correctly classified as PCV1 and PCV2, respectively.

Amino Acid Sequence↗

PubMed2000

DNA sequence of frog adenovirus.

The genome of frog adenovirus (FrAdV-1) was sequenced and found to be the smallest of all known adenovirus genomes. The sequence obtained was 26163 bp in size and contains a substantial direct repeat near the right terminus, implying that it was derived by recombination from a parental genome of only 25517 bp. The closest relative of FrAdV-1 proved to be turkey adenovirus 3, an avian adenovirus with no previously known near relative. Sequence comparisons showed that the two viruses have equivalent gene complements, including one gene the product of which is related to sialidases. Phylogenetic analyses supported the establishment of a fourth adenovirus genus containing these two viruses, in addition to the established genera Mastadenovirus: and Aviadenovirus: and the proposed genus Atadenovirus: Sixteen genes were identified as being conserved between these four lineages and were presumably inherited from an ancestral adenovirus.

Adenoviridae↗