| Summary: | 碩士 === 國立臺灣大學 === 獸醫學系 === 84 === In order to differentiate the infectious bronchitis virus (IBV)
isolates in Taiwan, polymerase chain reaction and restric- tion
fragment length polymorphism (PCR-RFLP) were used to type 12
Taiwan isolates of IBV. Two sets of primers were used in this
study to amplify the whole length of S1 glycoprotein gene. PCR
products were digested with three restriction enzymes, i.e.,
HaeIII, XcmI and BstYI. Four RFLP patterns were obtained and
they were different from those of all foreign IBV strains; the
foreign strains are divided into 4 different genetic groups, i.
e., Dutch, American, European and Massachusetts. Two IBV Taiwan
isolates were selected for S1 gene cloning and sequencing. The
nucleotide sequences of these two isolates have 94%
similiarity, and those of the deduced amino acid sequence are
90%. The two isolates are close to the Massachusetts group by
phylogenetic analysis. The amino acid sequences of the
proteolytic cleavage site between the S1 and S2 glycoproteins
of the two isolates are both RRFRR, and it is the same with the
Massachusetts group. Four consensus-like sequence, CTT(A/T)(A/T)
G, are noted in both of the two isolates but no recombination
are found.
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