SENSITIVITY OF THE PSEUDOMUREIN-CONTAINING GENUS METHANOBACTERIUM TO INHIBITORS OF MUREIN SYNTHESIS

The sensitivity to inhibitors of various steps of murein synthesis was studied with 6 strains of methanogenic bacteria. Four strains belong to the genus Methanobacterium, which contains pseudomurein in its cell walls. Neither this polymer nor murein is present in the 2 control organisms, Methanosarcina barkeri and Methanospirillum hungatii, which were resistant to all inhibitors of murein synthesis. The 4 strains of Methanobacterium were resistant to the antibiotics fosfomycin, D-cycloserine, vancomycin, penicillin G and cephalosporin C, all of which inhibit the synthesis or function of the peptide subunits of murein. The 4 strains were susceptible to bacitracin, nisin, gardimycin and enduracidin. The biosynthesis of murein and pseudomurein, respectively, may have some reactions of the so-called lipid cycle and the polymerization of the heteroglycan strands in common.