title: The cell wall of the obligate intracellular bacterial parasite of small free-living amoebae. I. Morphology and chemical composition of the rigid layer and peptidoglycan.
abstract: The obligate intracellular bacterial parasite "OIBP" of small free-living amoebae, discovered by Drozański (1956) was propagated in axenic culture of Acanthamoeba castellanii. The peptidoglycan prepared by chemical extraction of intact cells of the bacterium was examined in a transmission electron microscope and analysed chemically. Electron micrographs of heavy metal shadowed preparations revealed a bag-shaped membraneous structure resembling that of the peptidoglycan sacculi of Escherichia coli and the other gram-negative bacteria so far studied. The peptidoglycan may be present in a lipoprotein-peptidoglycan complex, as proteolytic enzyme treatment resulted in changes of the ultrastructure and in chemical composition. Results of chemical analysis of acid hydrolysed peptidoglycan indicate the presence of two aminosugars; glucosamine and muramic acid and also significant amounts of glycine together with three major amino acids; alanine, glutamic acid and diaminopimelic acid. It was shown that the peptidoglycan was, however, resistant to the hydrolytic action of egg-white lysozyme and to the lysosomal endo N-acetylmuramidases of amoebael origin.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000656:Amoeba / Q000382:microbiology* / Q000648:ultrastructure; D001419:Bacteria / Q000032:analysis*; D002473:Cell Wall / Q000032:analysis / Q000648:ultrastructure; D008854:Microscopy, Electron; D009113:Muramidase / Q000494:pharmacology; D010457:Peptidoglycan / Q000032:analysis* / Q000378:metabolism
chemical_list: D000596:Amino Acids; D010457:Peptidoglycan; D009113:Muramidase