Macromolecular Structure and Morphology of Native Glycogen Particles Isolated from Candida albicans

Abstract

A polysaccharide-rich particulate fraction was isolated from cytoplasmic extracts of Candida albicans by a procedure using differential centrifugation. The polysaccharide particles obtained after purification with deoxycholate treatment were essentially free of nitrogen and were identified chemically as polyglucosan, in which the glucosidic links were of alpha type. Both the response to amylolytic enzymes and the spectral characteristics of the iodine complexes of the polysaccharide particles were similar to those of rabbit liver glycogen. They also precipitated with concanavalin A, the glycogen value being assessed at 1.04. These data strongly indicated that the polysaccharide particles have the macromolecular structure characteristic of glycogen. The sedimentation analysis revealed that they were polydisperse, with a weight average sedimentation coefficient of 340 S . In negatively stained specimens, the glycogen particles were seen to form rosette-like structures consisting of a complex unit 40 to 150 nm in diameter. Such complex particles were composed of smaller globules that were fairly uniform in size with an average diameter of 32 nm.