Absence of an electron microscopic substructure in intact flagella of Proteus mirabilis and Bacillus subtilis

Abstract

Flagella of Proteus mirabilis D 52 appeared without any regular substructure in close to focus, high resolution electron micrographs of specimens negatively contrasted with potassium phosphotungstate or uranyl acetate. The same was true for many flagella of Bacillus subtilis ATCC 6051, but frequently these flagella exhibited a longitudinal linear pattern, interpretable as a bundle of about 3 nm-thick subfibrils. However, this pattern was probably caused by a slight degradation of the flagella, since the lined specimens were about 30% wider than the structureless ones. Moreover the Bacillus flagella were easily lost when washed with water or buffer. As controls, close to focus micrographs of mixtures of flagella and T6 bacteriophages were taken. The cross striations of the phage tails were clearly seen, spaced at 4 nm.