
Full text loading...
Summary: Seven flagella-shape mutants were isolated from a curly-flagella strain of Salmonella abortusequi. The motility in broth and spreading ability on semi-solid medium of these mutants as well as flagellar morphology were examined by dark field and electron microscopy. They were classified into the following five mutant types, heteromorphous, small-amplitude, para-curly, short and hooked-curly.
Each of these mutants manifests its characteristic flagellar shape and motility, and the spreading ability of these mutants on semi-solid medium decreases in the order: normal, heteromorphous, small-amplitude, para-curly, short, hooked-curly, curly.
Except in the small-amplitude and short mutants, the shape of a flagellar bundle of living bacteria under the dark-field microscope corresponded in each mutant to a spiral of the flagella observed under the electron microscope. In the small-amplitude mutant, transconformation of the flagellar bundle from small-amplitude to curly was observed in organisms suspended in 0.5% (w/v) methylcellulose solution. In the short mutant, the flagellar bundle was not seen in the dark-field microscope.
Difference of antigenic specificities between the flagella of the parental curly and each of the mutants were not detected when examined by absorption-agglutination tests.
From transduction analyses with P 22 phage, it was found that the traits of each of the four mutants heteromorphous, small-amplitude, para-curly, short were transferred with the structural gene of phase-2 flagellin and had no effect on the flagellar shape and motility in phase-1. From this, it is inferred that the characteristic flagellar shape and motility of these mutants are primarily to be attributed to the conformation of the flagellin which composes the mutant flagella.