Saga Y, Yanagisawa K
J Cell Sci. 1982 Jun;55:341-52. doi: 10.1242/jcs.55.1.341.
In Dictyostelium discoideum, cytological and physiological studies on macrocyst formation revealed that this process consists of at least two steps: the production of giant cells, which are believed to be formed from the fusion of cells of two opposite mating types, and the subsequent induction of macrocyst development by the giant cells. The conditions that had been considered formerly to be required for macrocyst formation, such as darkness at the presence of two cells of complementary mating types in heterothallic strains, were actually required only for the production of the giant cells. Once giant cells are produced, the surrounding cells can aggregate and form macrocysts even in the light. Furthermore, it was demonstrated that giant cells can switch the developmental mode of the surrounding cells to macrocyst formation. That is, if a critical number of the isolated giant cells are introduced into a cell population of a single strain of NC4, which normally would produce only fruiting-bodies, macrocysts are formed instead. When in the presence of giant cells, the development of macrocysts may be initiated by starvation. Therefore, if all cells are made to starve simultaneously development begins and proceeds synchronously. Using this technique of synchronous development, the developmental kinetics of enzyme activities were assayed during macrocyst and fruiting-body formation. Considerable differences in the patterns of those enzyme activities were demonstrated between the two developmental modes of D. discoideum.
在盘基网柄菌中，对大囊泡形成的细胞学和生理学研究表明，这个过程至少包括两个步骤：产生巨型细胞，据信这些巨型细胞是由两种相反交配型的细胞融合形成的；随后由巨型细胞诱导大囊泡发育。以前被认为是大囊泡形成所必需的条件，比如在异宗配合菌株中存在两种互补交配型细胞时处于黑暗环境，实际上仅对巨型细胞的产生是必需的。一旦产生了巨型细胞，即使在光照下，周围的细胞也能聚集并形成大囊泡。此外，已证明巨型细胞能够将周围细胞的发育模式转变为大囊泡形成。也就是说，如果将临界数量的分离巨型细胞引入通常只会产生子实体的单一NC4菌株的细胞群体中，反而会形成大囊泡。当存在巨型细胞时，大囊泡的发育可能由饥饿引发。因此，如果让所有细胞同时饥饿，发育就会开始并同步进行。利用这种同步发育技术，在大囊泡和子实体形成过程中测定了酶活性的发育动力学。结果表明，盘基网柄菌的这两种发育模式在那些酶活性模式上存在相当大的差异。
