NONMOTILE MINI-TRANSPOSON MUTANTS OF BORDETELLA-BRONCHISEPTICA EXHIBIT ALTERED ABILITIES TO INVADE AND SURVIVE IN EUKARYOTIC CELLS

Non-motile mutants of Bordetella bronchiseptica were generated after m ini-transposon mutagenesis. One non-motile mutant (designated VMM1) wa s derived from the bvg-positive strain BB7865 and four mutants (design ated AMM1-4) were derived from the isogenic bvg-negative strain BB7866 . Southern hybridisation analysis indicated that loss of motility was not due to the disruption of the flagellin subunit gene. Western blot and transmission electron microscopic analysis indicated that three of the five mutants expressed neither the flagellin subunit (40 kDa) nor flagella whereas one mutant expressed intact flagella under all condi tions tested. One unique bvg-negative mutant, AMM4, exhibited temperat ure-dependent repression of flagella biosynthesis and motility at 37 d egrees C. The ability of AMM4 to invade and survive in HeLa cells was significantly decreased.