The Functional Significance of Sporopollenin in the Morphogenesis of the Cellular Slime Moulds

点击翻译按钮获取中文摘要

During the morphogenetic events of culmination of the cellular slime moulds, the biosynthesis and deposition of stalk sheath and cell wall are of particular for an understanding of the mechanism of morphogenesis as well as the establishment of cell shape and rigidity. An alkali- and acid-resistant polymer (sporopollenin) is located on the stalk sheath of fruiting bodies as a bundle of fine fibrils (ca. 4 nm thick). Both the stalk sheath-constituting polymer (referred as to SSM) and the intact stalk cell wall were shown by several kinds of chemical analysis to be a homo-polymer of glucose. The stalk cell wall seemed to be composed of cellulose, as described previously. However, it is unlikely that the SSM is cellulose, because it is quite resistant to extensive cellulase-treatment and also is negative to PAS (periodic acid Schiff) reaction. Taken together these results, it is supposed that the SSM is a tight network of homo-polymer of glucose with a great many of branchings, thus being highly resistant to various chemical treatments. The biological significance of SSM is discussed, with special reference to the late developmental stages of slime mould cells.