| Summary: | 碩士 === 國立臺灣大學 === 獸醫學系 === 84 === Sixty strains of Riemerella anatipestifer(RA) were isolated
from ducks and geese with infectious serositis in Taiwan. The
strains were analysed by the biochemical tests, hemolytic test,
the sero- typing identification, proteins profile,
antimicrobial agent se- nsitivity, plasmids profile and
sequencing,cloning and expression of recombinant DNA genes,
electron microscope immunocytochemistry test. RA was Gram(-)
and short-rod bacteria. Carbohydrates were not oxidized and
fermented. They had β-hemolysis on blood agar. Serotypes of
the strains were distributed in 1-3 and 5-10. 60% of them were
serotype 2(36/60). In antimicrobial agent susceptibili- ty
tests, flumequine, nitrofurantoin and ceftiofur were the most
susceptible. Among the MIC90, penicillin(18μg/mL), ceftiofur(29
μg/mL) and flumequine(48μg/mL) minimum value. 76.7%(46/60) of
the isolates had plasmids. 60%(36/60) of them had 3.9Kb
plasmids, 11.7%(7/60) of them had 6.5Kb plasmids and 5%(3/60)
of them had 2.9Kb plasmids. The 3.9Kb plasmid was sequenced and
had 3,967bp. They were 57.4% homologous to the genes of the
virulence associa- ted proteins of the chromosomal DNA in
Dichelobcater nodosus. We used the 3.9Kb plasmids to designed
primers and processed polyme- rase chain reaction(PCR). The PCR
products could be found if pla- smids existed,the size about
290bp. The PCR products were ligated with vector and transfered
to E.coli. The fusion protein of the recombinant DNA was
produced by the bacteria and used to immunize rabbits. The
antiserum titer were 1024 times, test by agarose gel
immunodiffsion.By using western blotting test, we could find
the specific proteins although they had no plasmids. Under the
ele- ctron microscope, the size of RA was about 0.2-0.4μm×1-5
μm and it was a short-rod bacterium. The proteins of the 3.9Kb
plasmids could be produced and secreted.
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