Membrane modifications in nutritionally induced filamentous Escherichia coli B.

Nutritionally induced filamentous cell forms of Escherichia coli B were examined for their morphological and biochemical lesions. The filamentous forms showed no significant alteration in total DNA concentration, RNA synthesis, ability to form beta-galactosidase in response to isopropylthiogalactoside, or insensitivity to actinomycin D as compared to the normal cell form. The filamentous cells showed a marked decrease in the ability to incorporate N-acetylglucosamine-UL-(14)C into a phenol-soluble glycoprotein fraction relative to the normal cell form or relative to strain E-26 of E. coli grown in the filament-inducing medium. The filaments yielded an envelope-specific phenol-soluble protein fraction markedly reduced in or lacking three proteins as determined by acrylamide gel electrophoresis. Amino acid analysis, and chemical and enzymatic treatments of the envelope-specific phenol-soluble proteins showed striking differences between the fractions obtained from normal and filamentous cells. Electron microscope studies of divalent cation-induced aggregates of the envelope proteins showed different aggregation patterns dependent upon the cell form yielding the protein fraction.