Antagonistic Activity of Intestinal Lactobacteria from Domestic Fowl against Clinical Isolates of Salmonella enterica.

Strain parameters of Salmonellas and Lactobacteria affecting their antagonistic activity were studied using an original method. Real-time PCR was applied for measuring the decrease in the concentration of field isolates of Salmonellas isolated from chickens in the presence of field isolates of Lactobacteria also isolated from the gastrointestinal tract of chickens and broiler chickens. Dispersion analysis showed that the probability of suppression of Salmonella growth by Lactobacteria is determined by strain parameters of both Lactobacteria and Salmonellas (p<0.001). However, strain parameters of Lactobacteria were found to be more important that Salmonella strain parameters during co-culturing.

[Issues on evolution of CpG islands in genome of Marek's disease virus].

AIM: To study the hypothesis about influence of one form of epigenetic heredity--DNA metylation--on several criteria of pathogenicity of avian herpesviruses using Marek's disease virus (MDV) as a model. MATERIALS AND METHODS: Nucleotide sequences of genomic DNA of different serotypes of Marek's disease virus deposited in GenBank were used for the study. Analysis of distribution of CpG islands intra genome was performed with CPGPLOT program. RESULTS: Distribution and number of CpG islands differed markedly in pathogenic serotype 1 and apathogenic serotypes 2 and 3 of MDV. Diagrams of CpG islands distribution showed that serotypes 2 and 3 have significantly higher numbers of islands and they are evenly distributed across genomes. CONCLUSION: Lower numbers of CpG islands in MDV serotype 1 compared with serotypes 2 and 3 demonstrate presence of evolutionary pressure on pathogenic forms of MDV in order to escape from host cell's control of expression of viral proteins.