ANTIGENICITY AND N-TERMINAL AMINO-ACID-SEQUENCE OF A 35 KDA PORIN-LIKE PROTEIN OF LISTONELLA (VIBRIO) ANGUILLARUM - COMPARISON AMONG DIFFERENT SEROTYPES AND OTHER BACTERIAL SPECIES

Listonella (Vibrio) anguillarum, an important fish pathogen, is divide d into 10 serotypes according to O-antigens present on the outer membr ane. However, the biochemical and immunological properties of porin pr oteins have not been reported. In this study, the antigenicity and N-t erminal amino acid sequence of the 35 kDa porin-like-major outer membr ane protein (Omp35La) were compared among different serotypes of L. an guillarum as well as other bacteria. In Western blotting analysis, ant isera against Omp35La from strains of J-O-1, -2 and -3 serotypes could detect Omp35La, but not other proteins, in most L. anguillarum strain s and isolates of the genera Vibrio and Photobacterium. This antigenic ity of Omp35La is unrelated to the serotype and is conserved in relate d organisms. An N-terminal sequence showed identification with OmpF an d OmpC of Escherichia coli and Salmonella typhimurium. However, this s imilarity was lower when compared to other human pathogens. Thus it wa s concluded that Omp35La does not: contribute to the serotypes of L. a nguillarum, although the N-terminal structure is well conserved among different serotypes.