Cell Walls of Pseudomonas Species Sensitive to Ethylenediaminetetraacetic Acid

Abstract

Cell walls of 12 pseudomonads considered to be sensitive to ethylenediaminetetraacetic acid (EDTA) were prepared and analyzed. The wall of each species contained protein, peptidoglycan, loosely bound lipid, and lipopolysaccharide. The walls of Pseudomonas stutzeri and P. syncyanea were unusually susceptible to mechanical disintegration. The wall of P. syncyanea had an unusually high content of lipid and low contents of protein and peptidoglycan. Except for P. syncyanea , all the walls contained less phosphorus than the walls of the highly EDTA-sensitive P. aeruginosa and P. alcaligenes , but more than the walls of EDTA-resistant pseudomonads. The amino acid compositions of wall proteins were similar for all species. Amino sugars detected were glucosamine, galactosamine, muramic acid, and at least five unidentified components (possibly including fucosamine and quinovosamine). Glucose and rhamnose were the major neutral sugars in most walls. Galactose, mannose, fucose, and ribose were also detected, the last two each in a single species. Except for P. stutzeri and P. syncyanea , the walls had rather low contents of phospholipids (mainly cardiolipin, phosphatidylethanolamine, and phosphatidylglycerol in all species). An ornithine-containing nonphospholipid was present in all walls, and a hexuronosyldiglyceride was probably present in most walls. The fatty acid compositions of loosely bound lipids were qualitatively similar for all species: saturated C 16 and monoenoic C 16 and C 18 acids were the major components. Except for P. aureofaciens , the extraction of phosphorus on treatment of walls with EDTA at p H 9.2 was much less than for P. aeruginosa and P. alcaligenes .