Expression analyses and antiviral properties of the Beijing-You and White Leghorn myxovirus resistance gene with different amino acids at position 631.

Influenza is a topic of wide public concern, particularly because of the recent emergence of avian flu. The myxovirus resistance (Mx) protein has been shown to have an inhibitory effect on influenza virus and is therefore of great interest. This study examines the Mx protein in 8 local Chinese chicken breeds and 2 exotic chicken breeds. Amino acid 631, found in the Mx GTPase effector domain, was examined in 534 individuals by comparing PCR results, and individuals were separated into the A/A genotype or the G/G genotype, depending on whether amino acid 631 is an Asn or Ser. In the native breed, the frequency of G/G homozygotes is 0.780 (294/377). The Mx expression levels in tissues and chicken embryo fibroblast cells with different genotypes were also studied. The A/A individuals from Beijing-You and White Leghorn breeds had higher Mx expression levels than G/G individuals. The liver, heart, and spleen had higher expression levels than muscle or kidney. The A/A chicken embryo fibroblast cells had higher antiviral activity against vesicular stomatitis virus and Newcastle disease. We provide the first report examining the expression level and antiviral activity of different Mx alleles of nucleotide 2216(S631N) genotypes. This study lays a good foundation for correlative studies examining genotype and antiviral function.

Toxicity of organic pollutants to seven aquatic organisms: effect of polarity and ionization.

The toxicity of organic chemicals to Vibrio fischeri, river bacteria, algae, Daphnia magna and fishes were analysed. The results showed that the toxicity of chemicals to narcotics was dependent on hydrophobicity. A single model for both polar and non-polar narcotics was developed by inclusion of a polarity descriptor as well as the hydrophobic parameter. The highly hydrophobic polar narcotics could be treated as non-polar narcotics because their polar functional group(s) make(s) a relatively small contribution to polarity as compared with their hydrophobicity. In order to investigate the toxic mechanism of action for reactive compounds, the response-surface approach was used to develop models derived from easily calculated descriptors. The stepwise analysis selected the octanol/water partition coefficient and a polarity descriptor to parameterize bio-uptake and reactivity, respectively, for seven species. Benzoic acids can be easily absorbed into the unicellular bacteria, but this is not the case for multicellular D. magna and fish. Their toxicity to V. fischeri is much higher than that to D. magna and carp. Regression analysis was performed based on the model that we developed for ionizable compounds. Good correlations were observed by introducing the correction factor for ionizable compounds. The toxic mechanisms are discussed.