Molecular identification of reovirus in broiler type flocks in Golestan province, Iran

BACKGROUND

Avian reovirus (ARV) has a global distribution in nature and most clinical signs are found in broiler type chickens.

AIMS

This study was conducted to detect and identify reovirus infections from vaccinated breeder chickens and their progenies.

METHODS

A total of 20 tissue and blood samples were collected from vaccinated broiler breeders and their progenies with gastrointestinal or performance problems during peak production. Antibody titers were measured by indirect enzyme-linked immunosorbent assay (ELISA) tests. RNA extraction from tissue samples was performed and cDNA was prepared and directly used in the polymerase chain reaction (PCR). Nucleotide sequences were bilaterally determined using internal primers. The analysis of the nucleotide sequences and their related amino acids was performed by the specialized Molecular Evolutionary Genetics Analysis software (6th version).

RESULTS

The virus variant was detected in two vaccinated broiler breeders and five broiler flocks. The vaccine strains in breeder flocks included S1133, SS412, 1733, 2408 belonging to genotype 1 from the reovirus phylogenetic tree. Sequence 7 from the isolated reovirus based on the σC revealed that they were different from the reovirus vaccine, and that 6 isolates belonged to genotype 1 of the phylogenetic tree while 1 isolate belonged to branch 4 of the phylogenetic tree.

CONCLUSION

The study showed that the new reovirus strain isolated from vaccinated birds differs from common strains used in the vaccines. It is therefore essential to prevent the effects of the field reovirus on the performance of industrial poultry, by updating and inventing new commercial vaccines, live and killed, against the reovirus.

The cytosolic cochaperone Sti1 is relevant for mitochondrial biogenesis and morphology

Most mitochondrial proteins are synthesized in the cytosol prior to their import into the organelle. It is commonly accepted that cytosolic factors are required for delivering precursor proteins to the mitochondrial surface and for keeping newly synthesized proteins in an import-competent conformation. However, the identity of such factors and their defined contribution to the import process are mostly unknown. Using a presequence-containing model protein and a site-directed photo-crosslinking approach in yeast cells we identified the cytosolic chaperones Hsp70 (Ssa1) and Hsp90 (Hsp82) as well as their cochaperones, Sti1 and Ydj1, as putative cytosolic factors involved in mitochondrial protein import. Deletion of STI1 caused both alterations in mitochondrial morphology and lower steady-state levels of a subset of mitochondrial proteins. In addition, double deletion of STI1 with the mitochondrial import factors, MIM1 or TOM20, showed a synthetic growth phenotype indicating a genetic interaction of STI1 with these genes. Moreover, recombinant cytosolic domains of the import receptors Tom20 and Tom70 were able to bind in vitro Sti1 and other cytosolic factors. In summary, our observations point to a, direct or indirect, role of Sti1 for mitochondrial functionality.