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Relationships between Cell Cycle and Conjugation in 3 Hypotrichs *
Author(s) -
LUPORINI PIERANGELO,
DIN FERNANDO
Publication year - 1975
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1975.tb05229.x
Subject(s) - mitosis , cell cycle , biology , dna replication , mating , meiosis , cell division , population , microbiology and biotechnology , dna synthesis , micronucleus , micronucleus test , cell , dna , genetics , chemistry , gene , toxicity , demography , organic chemistry , sociology
SYNOPSIS. Relationships between the cell cycle and the beginning of conjugation were analyzed for 3 hypotrichs: Diophrys scutum, Oxytricha bifaria , and Euplotes crassus. The first 2 species enter conjugation with micronuclei in G 1 ; the latter species with a micronucleus in G 2 . The 1st micronuclear division of conjugating E. crassus is mitotic. Thus meiotic DNA replication occurs when the cells of each species have already entered the mating process. Cells from asynchronous populations start conjugation with their macronuclei primarily in G 1 or more rarely at the beginning of the S stage in a percentage significantly different from that expected on the basis of random mating among all cells in the population. Also, macronuclear replication, when already begun, was blocked in cells undergoing conjugation. Therefore only the G 1 or the very early S stages of the cell cycle are compatible with conjugation in the 3 analyzed species.