[Lipopolysaccharides from thermosensitive mutants of Escherichia coli K12 (author's transl)]

Thermosensitive mutants of Escherichia coli K12 were grown at 30 degrees C and 40 degrees C. The serologic properties and the composition of their lipopolysaccharides were investigated. The inhibition of hemagglutination by the lipopolysaccharides of various mutant strains was tested against the anti-E. coli K12 CR34 system. An inhibition was observed with all the mutants but one, CR34 T83 which had no inhibitory effect. Chemical analysis of lipopolysaccharides and mass spectrometric analysis of their methylated derivatives indicated the presence of the same components in the various lipopolysaccharides: glucose, galactopyranose, galactofuranose, heptopyranose and heptofuranose. However the 2,3,4 tri-O-methyl glucose is missing in the lipopolysaccharide of the mutant T83. This result agrees with the absence of a substituent on the 6-position of the non-reducing core-terminal glucose. The lipopolysaccharide of the T83 mutant has the complete core-type of E. coli K12. The relations of mutations with modifications of the composition of inner and outer envelopes in various mutants are discussed.