Sharpe P T, Knight G M, Watts D J
Biochem J. 1984 Feb 1;217(3):839-43. doi: 10.1042/bj2170839.
A fluorimetric assay has been used to determine the DNA content of amoebae of Dictyostelium discoideum during growth and development. Amoebae grown in axenic culture tended to be multinucleate and had a greater DNA content than amoebae grown with a bacterial substrate, which were mononucleate. During the first 10 h of development there was little change in the DNA content of amoebae grown with a bacterial substrate, but the average DNA content per cell in amoebae grown axenically decreased as the amoebae became virtually mononucleate. Amoebae at 10 h development that had been harvested during exponential axenic growth were divided into two populations by countercurrent distribution in a polymer two-phase system. DNA content indicated that one population was largely in the G2-phase of the cell cycle, whereas the other population was largely in the G1-phase. Similar results were obtained at 10 h development with amoebae harvested during the stationary phase of axenic growth, although these amoebae start development all in the G2-phase of the cell cycle. Spores had a low DNA content, indicating that they were in G1-phase. It is proposed that all amoebae in G2-phase after early development differentiate, after mitosis, into spores and that stalk cells are formed from amoebae that remain in G1-phase after 10 h development.
一种荧光测定法已被用于测定盘基网柄菌变形虫在生长和发育过程中的DNA含量。在无菌培养中生长的变形虫往往是多核的，并且其DNA含量比在细菌底物上生长的单核变形虫更高。在发育的最初10小时内，在细菌底物上生长的变形虫的DNA含量几乎没有变化，但无菌培养生长的变形虫随着几乎变成单核，其每个细胞的平均DNA含量下降。在指数期无菌生长期间收获的处于发育10小时的变形虫，通过在聚合物两相系统中的逆流分配被分成两个群体。DNA含量表明一个群体主要处于细胞周期的G2期，而另一个群体主要处于G1期。在无菌生长稳定期收获的处于发育10小时的变形虫也得到了类似的结果，尽管这些变形虫在细胞周期的G2期开始发育。孢子的DNA含量低，表明它们处于G1期。有人提出，早期发育后处于G2期的所有变形虫在有丝分裂后分化为孢子，而柄细胞由发育10小时后仍处于G1期的变形虫形成。
