Characterization of duck plague virus stability at extreme conditions of temperature, pH and salt concentration.

Duck plaque virus (DPV) belongs to the family Herpesviridae. The live attenuated vaccine is the only way to protect the ducks from DPV infection. The ineffectiveness of vaccine is one of the major causes of DPV outbreaks in the field condition. DPV is not well characterized for its pathogenicity and molecular biology in poultry. In the present study, we discuss briefly about the biology of DPV and its proteins under different conditions of temperature and pH in order to evaluate its infectivity under adverse physical conditions. Our results indicate that the DPV is non-infective above 42 °C and unstable above 65 °C. In addition, change in pH or salt concentrations significantly decreases the stability of the DPV. The study will be useful in estimating an optimum storage condition for DPV vaccines without causing any deterioration in its viability and effectiveness.

Synonymous codon usage pattern in glycoprotein gene of rabies virus.

Rabies virus (RABV) is the causative agent of a fatal nervous system ailment. The disease is zoonotic and prevalent in many developing countries. The glycoprotein (G) of RABV is the major antigenic determinant of the virus and plays a pivotal role in its neurovirulence. Various aspects of 'G' protein biology have been explored, but the factors affecting the nucleotide choice and synonymous codon usage have never been reported. In the present study, we have analyzed the relative synonymous codon usage and effective number of codons (Nc) using 132 'G' protein genes of RABV. Corresponding analysis was used to calculate major trends in codon usage. The correlation between base composition and codon usage as well as the plot between Nc and GC3 suggest that mutational pressure is the major factor that influences the codon usage in the G gene of RABV. In addition, factors like aromaticity, aliphatic index and hydropathy have shown slight correlation suggesting that natural selection also contributes to the codon usage variations of the 'G' gene. In conclusion, codon usage bias in 'G' gene of RABV is mainly by mutational pressure and natural selection.

Analysis of synonymous codon usage in spike protein gene of infectious bronchitis virus.

Infectious bronchitis virus (IBV) is responsible for causing respiratory, renal, and urogenital diseases in poultry. IBV infection in poultry leads to high mortality rates in affected flocks and to severe economic losses due to a drop in egg production and a reduced gain in live weight of the broiler birds. IBV-encoded spike protein (S) is the major protective immunogen for the host. Although the functions of the S protein have been well studied, the factors shaping synonymous codon usage bias and nucleotide composition in the S gene have not been reported yet. In the present study, we analyzed the relative synonymous codon usage and effective number of codons (Nc) using the 53 IBV S genes. The major trend in codon usage variation was studied using correspondence analysis. The plot of Nc values against GC3 as well as the correlation between base composition and codon usage bias suggest that mutational pressure rather than natural selection is the main factor that determines the codon usage bias in the S gene. Interestingly, no association of aromaticity, degree of hydrophobicity, and aliphatic index was observed with the codon usage variation in IBV S genes. The study represents a comprehensive analysis of IBV S gene codon usage patterns and provides a basic understanding of the codon usage bias.