Structure and Chemistry of Walls of Rods, Cocci and Cystites of Arthrobacter globiformis

Abstract

A. globiformis NCIB10683 was grown under different conditions in continuous and batch culture to produce rods, cocci and cystites. All forms were resistant to lysozyme and enzyme L1 [from Cytophaga] and did not autolyse readily. Walls contained polysaccharide, made up of glucose, galactose and rhamnose, and peptidoglycan and P. The polysaccharide constituted about 60% of the wall of each form, although the molar ratios of glucose, galactose and rhamnose varied from 1:1:1 in the cystites to 1:3:2 in rods and 1:3.5:3 in cocci. The molar ratios of alanine, glutamic acid, threonine and lysine in the peptidoglycan were similar in all 3 preparations (4:1:1:1). EM showed that the wall was structurally homogeneous but was thicker in cocci (10-27 nm) than in rods (6-12 nm). The wall in cystites varied in thickness (6-40 nm) and was sometimes distorted due to the accumulation of large amounts of glycogen which expanded the organism and displaced the ribosomes from most parts of the organism. Glycogen granules were also seen in rods but never in cocci. Division of Arthrobacter was by binary fission and budding. Buds could usually be distinguished from parent organisms since the latter contained less ribosomes and mesosomes. Large periplasmic spaces were found, especially in budding cells. Cross-wall formation differed in binary fission and budding.