Genetic diversity of species Fowl aviadenovirus D and Fowl aviadenovirus E

Complete genomes of eight reference strains representing different serotypes within species Fowl aviadenovirus D (FAdV-D) and Fowl aviadenovirus E (FAdV-E) were sequenced. The sequenced genomes of FAdV-D and FAdV-E members comprise 43,287 to 44,336 bp, and have a gene organization identical to that of an earlier sequenced FAdV-D member (strain A-2A). Highest diversity was noticed in the hexon and fiber genes and ORF19. All genomes, sequenced in this study, contain one fiber gene. Phylogenetic analyses and G+C content support the division of the genus Aviadenovirus into the currently recognized species. Our data also suggest that the strain SR48 should be considered as FAdV-11 instead of FAdV-2 and similarly the strain HG as FAdV-8b. The present results complete the list of genome sequences of reference strains representing all serotypes in species FAdV-D and FAdV-E

Genetic Diversity of Serine Protease Inhibitors in Myxozoan (Cnidaria, Myxozoa) Fish Parasites

We studied the genetic variability of serine protease inhibitors (serpins) of Myxozoa, microscopic endoparasites of fish. Myxozoans affect the health of both farmed and wild fish populations, causing diseases and mortalities. Despite their global impact, no effective protection exists against these parasites. Serpins were reported as important factors for host invasion and immune evasion, and as promising targets for the development of antiparasitic therapies. For the first time, we identified and aligned serpin sequences from high throughput sequencing datasets of ten myxozoan species, and analyzed 146 serpins from this parasite group together with those of other taxa phylogenetically, to explore their relationship and origins. High intra- and interspecific variability was detected among the examined serpins. The average sequence identity was 25-30% only. The conserved domains (i.e. motif and signature) showed taxon-level differences. Serpins clustered according to taxonomy rather than to serpin types, and myxozoan serpins seemed to be highly divergent from that of other taxa. None of them clustered with their closest relative free-living cnidarians. The genetic distinction of myxozoan serpins further strengthens the idea of an independent origin of Myxozoa, and may indicate novel protein functions potentially related to parasitism in this animal group

Species Fowl aviadenovirus B Consists of a Single Serotype despite Genetic Distance of FAdV-5 Isolates

Fowl adenoviruses (FAdVs) are infectious agents, mainly of chickens, which cause economic losses to the poultry industry. Only a single serotype, namely FAdV-5, constitutes the species Fowl aviadenovirus B (FAdV-B); however, recently, phylogenetic analyses have identified divergent strains of the species, implicating a more complex scenario and possibly a novel serotype. Therefore, field isolates of the species were collected to investigate the contemporary diversification within FAdV-B, including traditional serotyping. Full genomes of fourteen FAdV-B strains were sequenced and four strains, possessing discriminatory mutations in the antigenic domains, were compared using virus cross-neutralization. Essentially, strains with identical antigenic signatures to that of the first described divergent strain were found in the complete new dataset. While chicken antiserum against FAdV-5 reference strain 340 could not neutralize any of the newly isolated viruses, low homologous/heterologous titer ratios were measured reciprocally. Although they argue against a new serotype, our results indicate the emergence of escape variants in FAdV-B. Charge-influencing amino acid substitutions accounted for only a few mutations between the strains; still, these enabled one-way cross-neutralization only. These findings underline the continued merit of the cross-neutralization test as the gold standard for serotyping, complementary to advancing sequence data, and provide a snapshot of the actual diversity and evolution of species FAdV-B

A pathogenitásért és az állati sejtek manipulálásáért felelős, új adenovírus fehérjék keresése = Search for novel adenovirus proteins responsible for pathogenicity and the manipulation of animal cells

Az adenovírusok sejtreceptorokhoz történő kapcsolódásában részt vevő kapszidfehérjék (a pentonbázis és fiberfej) határozzák meg a vírus szöveti és sejt-specificitását. A sejtek manipulálásáért és az adenovírusok kórokozó képességéért azonban alapvetően a korai kifejeződésű gének által kódolt fehérjék felelősek. Eddig ismeretlen adenovírusokat találva főleg hüllőkben, vadmadarakban, rágcsálókban, denevérekben és majmokban, valamint vírusgenom szekvenálást és elemzést végezve (pl. teljes hal-, gyík-, liba-, egér-, denevér-, majom- és humán adenovírus genomok) számos feltehetően korai, új gén létezését sikerült kimutatni. Vizsgáltuk az ezek által kódolt fehérjék evolúcióját, sokféleségét, változékonyságát, természetes mutáció okozta rövidülését, delécióját vagy duplikációját, a sejtreceptor-kötő helyek meglétét vagy hiányát. A hal-adenovírus feltételezett szulfotranszferáz homológjának génjét és több állati adenovírusból a fiberfejet kódoló génszakaszt bakteriális kifejező rendszerbe klónoztuk és teszteltük kifejeződésüket. Következtetéseket vontunk le a vizsgált gének funkciójára, esetleges nélkülözhetőségükre, valamint az egyes vírusok között megfigyelhető pathogenitási és más biológiai különbségek okára vonatkozóan. | The capsid proteins (penton base and the fiber knob), which take part in the attachment to the cellular receptors, play crucial role in the organ and tissue tropism of adenoviruses. Nonetheless, the proteins coded by the early genes are primarily responsible for the manipulation of cells and for the pathogenicity of these viruses. By finding novel adenoviruses mainly in reptiles, wild birds, rodents, bats and monkeys, and by sequencing and analysing adenovirus genomes (e.g., the full genome of the sturgeon, lizard, goose, mouse, bat, monkey and human adenoviruses), the existence of numerous such supposedly early genes was revealed. We studied the evolution, diversity, variability, truncation caused by natural mutation, deletion, duplication of these proteins as well as the presence or lack of cellular receptor binding sites. The gene of a sulfotransferase homologue of sturgeon adenovirus and gene fragments coding the fiber knobs of several animal adenoviruses were cloned and expressed in bacterial expression systems. We drew several conclusions concerning the function, possible non-essential status of these genes, and the reason for the observed differences in the pathogenicity and other biological properties of the adenoviruses examined