Biology session

I joined a year ago a research team that primarily focuses on deciphering the phylogenetics of adeno- and herpesviruses. My aim was to detect adenoviruses in samples of representatives of the order of rodents. Little data is available on adenoviruses occurring in this particular group of mammals. It seemed, from a theoretical point of view, interesting to examine the presumed co-evolution between hosts and their adenoviruses in the case of rodents. It is important to know the infectiousnes of this group, as rodents are very common pets nowdays. We have to () a method to () the experimental an wild animals. The method to survey the experimental and wild animals is necessary.

In the course of my project I primarily examined DNA extracted from ther liver and gut of dead animals. I also studied feces samples from live animals and nucleic acid extracts previously screened for other viruses. I received samples from the Budapest Zoo, the Central Veterinary Institute and from the animal house of Sanofi Aventis pharmaceutics. Dr. Miklós Gyuranecz accomodated me with a part of his field rodent samples collected for other purposes. One or more samples were examined from the following species: Guinea pig, Chinchilla, Agouti, Common hamster, European hare, Syrian hamster, and Red squirrel. The nested PCR I used is suitable to detect a fragment of the adenoviral DNA polymerase gene. This is the most conserved gene in adenoviruses examined so far. Information of the DNA fragment of 300 basepairs is sufficient to classify the viruses on the level of genus, on the basis of which I also attempted to amplify by PCR further genes like hexon or IVa2. I determined by applying the PCR primers the nucleotide sequence of the DNA products of the positive samples. It was occasionally necessary to clone the amplified genome fragment. Using the derived amino acid sequence and by means of phylogenetic analysis I carried out phylogenetic tree reconstructions.

In the course of parallel laboratory experiments, according to phylogenetic tree reconstruction, a sequence closely related to the mouse adenovirus was derived from gut and lung samples of a Common buzzard as well as from two environmental samples coming from the floors of zoo cages. In the first case we presumed that it was the adenovirus of the animal’s prey that had likely been detected. In the case of the environmental samples the role of free ranging pests (mouse or rat populations) can be suspected. I have been further experimenting with these samples.

The phylogenetic results confirm the research team’s former theories relating to co-evolution, in so far as the phylogenetic lineage of the identified rodent adenoviruses correspond to that of their vertebrate hosts.