Cell wall regeneration of Canadida spec. protoplasts

A yeast of the genus Candida which is able to grow on n-alkanes was characterized by biochemical investigations: Crabtree effect, inhibition of ammonium utilization by asparagine, changes in the concentration of polysaccharides mainly concentrated in the cell wall. The yeast was compared biochemically and electron-microscopically with its pure protoplast population, and the regeneration of the cell wall was studied. In correspondence with the asynchronously developing accumulation of glucan and manna, electron microscopical studies have first only revealed glucan fibrils. Matrix formation (mannan) occurs only in the second stage of regeneration. After a regeneration period of 9 hours, the polysaccharides in the former protoplast population reached the concentration of the period before enzymatic removal of the cell wall. A tube-like structure observed by light microscopy during the early stages of regeneration is shown electron-microscopically to consist of a fibrillar network without matrix. Between newly formed cell wall and plasma membrane, in some cells groups of large flat vesicles were found, whose fracture faces are free of particles. After protoplast formation the invaginations of the plasma membrane arrange themselves in rows one behind the other. These findings are supported by further evidence suggesting that the invaginations are structures on the basis of lipid domains.