Study On The Biological Character Of 25 Strains Of Aeromonas And Their Outer Membrane Protein Patterns

25 strains of Aeromonas were isolated from aquatic animals such as turtles and fishes in some aqua-farms in Anhui province. On the basis of their morphologic, physiological and biochemical characters, the 18 strains of them were identified as Aeromonas sobria, other 7 strains as Aeromonas hydrophila.In the immunoelectrophoresis (IE) 3-8 bands of precipitable protein would be observed between the antigen of A. hydrophila or A. sobria and its special anti-serum or the anti-serum to other species. This phenomenon of the cross-reaction indicated that there might be some common antigens in different species or strains,, of Aeromonas.The 22 strains of Aeromonas were pathogenic to mice except 3 strains (XA4, BA5, BA6). 7 strains of Aeromonas (BA1, BA3, BA10, BAH, BA15, BA16, XA23) were pathogenic to crucian carp, BA1, BA3 were A. hydrophila and had a lethal rate of 66.7% and 100% to"crucian carp respectively. Other 5 strains were Aeromonas sobria and had a lethal rate to crucian carp from 33.3% to 100%. These suggest that these strains of Aeromonas had pathogenicity in the different degree to mice and crucian carp.The outer membrane proteins (OMPs) of 8 strains of Aeromonas (BA1, BA3, BA6, Ml, BA16, BA15, BA10, XA23) were extracted with ultrasonic breaking bacterial cells-sarcosyl insoluble method and analyzed by SDS-PAGE. 5 strains of A. sobria (Ml, BA16, BA15, BA10, XA23) and 3 strains of A. hydrophila (BA1. BA3, BA6) respectively had themselves OMP profiles, namely A. sobria had total 7-9 bands between the molecular weight (MW) from 2.01 X 104 to 6.62X 104and 4 common bands with the MW 2.4X 104, 3.0X 104, 3.7X JO4, 4.2 X 104 and A. hydrophila had total 6 bands with the MW from 2.01 XTO4 to 6.62 X 104 and 4 common bands with the MW 2.3 X104, 3.1 X 104, 3.75 X 104, 4.0 X 104. In addition, there would be the difference of the protein bands in the quantity and mobility between the A. hydrophila and A. sobria and among the strains, which might possibly because the resources of bacteria from the animals. According to the average linkage cluster analysis of the OMPs of 8 strains of Aeromonas., there would be a little relationship between two species and a close relationship between strains in the same species.