FIG. 7.

Comparison of the spore wall and the vegetative cell wall. An electron micrograph of a germinating ascospore is shown. On the left side, the cell is surrounded by spore wall with its four layers, mannan, beta-glucan, chitosan, and dityrosine (indicated by M, B, C, and D, respectively, in the close-up and in the cartoon). On the right side, the tip of the germinating cell is bounded by vegetative cell wall with it predominant beta-glucan and mannan layers (indicated by B and M). The mannan layer of the cell wall appears to be continuous with that of the spore wall. PM, plasma membrane.