PURIFICATION AND CHARACTERIZATION OF A GALACTOSE-SPECIFIC LECTIN FROMTHE EGGS OF COHO SALMON ONCORHYNCHUS-KISUTCH AND ITS INTERACTION WITHBACTERIAL FISH PATHOGENS

The yolk of coho salmon Oncorhynchus kisutch eggs contains a lectin wh ich proved capable of binding to Aeromonas salmonicida cells, but show ed no such activity with other fish pathogens such as A. hydrophila, V ibrio anguillarum, V. ordalii, or Renibacterium salmoninarum. The inte raction between the lectin and A. salmonicida was demonstrated by a te st in which the protein was adsorbed onto bacterial cells. Boiling the bacterial cells for 1 h did not alter their ability to adsorb the lec tin. The lectin was purified by affinity chromatography on D-galactose -Sepharose 4B, and was shown by SDS-PAGE to be a 24.5 kDa protein; it was heat stable and its binding property was inhibited by D-galactose, D-glactosamine, and L-rhamnose. The amino acid composition and N-term inal amino acid sequence of the purified lectin were also determined. The amino acid sequence was in places reminiscent of the sequences fou nd in recognition molecules such as antibodies and certain cell recept or sites.