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Cell cycle analysis in a multinucleate green alga, Boergesenia forbesii (Siphonocladales, Chlorophyta) *
Author(s) -
Motomura Taizo
Publication year - 1996
Publication title -
phycological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.438
H-Index - 44
eISSN - 1440-1835
pISSN - 1322-0829
DOI - 10.1111/j.1440-1835.1996.tb00033.x
Subject(s) - multinucleate , biology , mitosis , cell cycle , nucleus , aphidicolin , cell division , microbiology and biotechnology , interphase , prophase , cell nucleus , telophase , biophysics , cell , anaphase , genetics , meiosis , gene
SUMMARY The cell cycle (nuclear division cycle) of a multinucleate green alga, Boergesenia forbesii (Harvey) Feldmann was studied using microspectrophotometry and BrdU incorporation techniques. Mitosis was observed frequently 1‐4 h after the beginning of the light period, on a 16:8 h LD cycle at 25°C. Mitotic nuclei formed discrete patches. Other nuclei remained in the G 1 period. The DNA synthetic phase (S phase) was estimated to last about 12 h from microspectrophotometric study using aphidicolin inhibition just before the S phase and release from it. The G 2 period was estimated to be about 2 h, because a labeled prophase nucleus could be detected when the samples were labeled with BrdU continuously over 3 h. The incorporation pattern of BrdU changed through the S phase nucleus. In early S phase, BrdU staining was detected as many dots in the entire nucleus, while in late S phase, it was detected as several discrete regions along the nuclear membrane. Almost all nuclei in B. forbesii were in the G 1 stage after nuclear division, and the nuclei in several patches of the cell simultaneously initiated DNA synthesis. Once the nuclei entered into S phase, these nuclei continued into G 2 and mitosis. In other words, the cell cycle regulation of entrance into S phase from G 1 is an important factor in the growth and morphogenesis in B. forbesii.