Molecular Characteristics of S1 Gene of Infectious Bronchitis Virus Isolated from Chicken Proventric

<正> Infectious bronchitis virus was isolated from swollen proventriculi of clinically ill chicken. The suspected virus samples (2/97, 3/97, 1/98) were adapted in SPF chicken embryos for virus isolation and identification. All the virus isolates were able to agglutinate chicken erythrocytes after treatment with trypsin, and interfer with the reproduction of Newcastle disease virus in chicken embryos, and have low antigenic relat-edness values with reference positive IBV. The isolates 2/97, 3/97, 1/98 RNAs extracted from the allantoic fluid of inoculated embryonated eggs were converted to cDNA by reverse transcription with 3’-primer of S1 gene of (IBV). Polymerase chain reaction (PCR) was performed with two primers which span the S1 gene. Amplified product of 1. 93 kb was subjected to EcoR I and BamH I digestion and the fragments obtained were the same as expected size. The PCR product was ligated to pBlueScript-SK ( + ) vector, and its nucleotide sequence was determined by the dideoxy-mediated chain terminat