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Cell division induced by mechanical stimulation in starved Tetrahymena thermophila : cell cycle without synthesis of macronuclear DNA
Author(s) -
Iwamoto Masaaki,
Sugai Toshiro,
Nakaoka Yasuo
Publication year - 2004
Publication title -
cell biology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 77
eISSN - 1095-8355
pISSN - 1065-6995
DOI - 10.1016/j.cellbi.2004.04.004
Subject(s) - cell division , tetrahymena , macronucleus , biology , microbiology and biotechnology , dna synthesis , stimulation , cell cycle , dna , cell , mitosis , genetics , neuroscience
Starved Tetrahymena thermophila cells underwent synchronous cell division 2 h after a mechanical stimulation. The macronucleus showed no obvious increase in DNA content before the cell division in the starvation medium, and the DNA content was decreased after the cell division. On the other hand, when the starved cells were given nutrient‐supplied medium immediately after the mechanical stimulation, cell division was delayed for 3 h. This period was almost the same as that for G1 cells in the stationary culture to first division after transfer to fresh nutrient medium. These results suggest that the mechanical stimulation induces an early division of starved cells, skipping the macronuclear S‐phase with the starved cells probably becoming trapped in G1. Starved cells that had finished division soon formed mating pairs with cells of the opposite type. These observations lead us to propose that cell division in starvation conditions may be necessary to reduce macronuclear DNA content prior to the mating of T. thermophila .