Ref ID : 7565
Nicola Ricci, R. Banchetti, and R. Cetera; Initiation of Meiosis and Other Nuclear Changes in Two Species of Oxytricha. Protistologica XVI(3):413-417, 1980
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The conjugation of Oxytricha bifaria and O. hymenostoma (Ciliata, Hypotricha) was investigated as a cellular model, in which only two types of cells are involved in processes leading to the induction of meiosis and to the other nuclear changes (macronuclear breakdown, formation of synkarion), typical of the sexual reproduction of Ciliates. Partners of the two species were split at successive stages of a sterotyped preconjugant behaviour ("Visible Reaction"), leading to pair formation, namely after 10 to 20 minutes from the beginning of the cortical cell interactions. The meiosis was found to be irreversibly induced soon after the partner membrane fusion. The rotating partner is irreversibly induced to such a nuclear process about three minutes earlier than the left, still partner. In O. hymenostoma moreover, a new kind of para-vegetative reproduction (= S.M.R., for Slow Macronuclear Reduplication) was reported for the split partners belonging to the mating type 301. It was also found that the rotating partner, always belonging of the 301 type, unable to undergo meiosis, inhibits the meiotic processes, although already triggered, in its potentially normal, still partner, when it fuses with it.