title: Pleiotropic consequences of mutations towards antibiotic-hypersensitivity in Serratia marcescens.
abstract: Various mutants (oxas) were isolated from Serratia marcescens SM-6 by selecting for hypersensitivity towards oxacillin. All mutants found are highly pleiotropic and able to yield spontaneous revertants which behave like the wild-type. Mutant W 1421 mostly studied shows the following phenotypic properties not found in the wild-type: (1) The growth is hypersensitive to various antibiotics, detergents and dyes which differ remarkably in their chemical structure and antibacterial action-mechanism, (2) the cells can be easily solubilized by 0;05% Sodium-dodecyl-sulfate, (3) the cells allow the adsorption of the rough-mutant specific Salmonella phage 6SR; (4) strong cellular binding of crystal violet, (5) agglutination of the cells in 0.3% auramin solution and (6) reduced formation of red pigment. Strain W 1421 is assumed to be a lipopolysaccharide-defective mutant. The outer membrane of mutant W 1421 analyzed by Sodium-dodecylsulfate-polyacrylamide gel electrophoresis possesses a single protein less than that of the wild-type. Mutant W 1421 is further characterized by its low exolipase activity; exoprotease and exonuclease activities are as in the wild-type. This specific exoenzyme deficiency can be overcome either by backmutation to oxacillin-resistance or by growing mutant W 1421 in a medium supplemented with certain non-metabolizable polysaccharides, e.g. glycogen or pectin B. Both polysaccharides increase the exolipase activity of the wild-type too.
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000032:analysis; D002462:Cell Membrane / Q000648:ultrastructure; D004396:Coloring Agents / Q000494:pharmacology; D003902:Detergents / Q000494:pharmacology; D009154:Mutation; D010068:Oxacillin / Q000494:pharmacology; D010403:Penicillin Resistance; D012706:Serratia marcescens / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004396:Coloring Agents; D003902:Detergents; D010068:Oxacillin