Ref ID : 7531

Antonio Torres, C. Morenza, C. Fedriani, and A.M. Gutierrez-Navarro; Nuclear Cycles and DNA Contents in Laurentia acuminata (Hypotrichida, Oxytrichidae). Protistologica XV(2):133-138, 1979

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By using cytophotometric techniques the cellular cycle and the relative DNA contents in both macro and micronucleus of Feulgen-stained Laurentia acuminata have been established. The cellular cycle requires 9.5+/-1 hours at 20+/-1 degrees C. For the macronuclear cycle stages the following aproximate durations were estimated: G1, 4.5 hours; S, 4 hours; division, 1 hour; G2, very short or lacking. Those for micronuclear cycle: G1, 7.5 hours; S, 1 hour; division, 1 hour; G2, absent. The average DNA content per micronucleus (mi) was 43.57 a.u. The total macronuclear DNA content per cell (average: 154.65 x mi) found in cells with four macronuclear fragments was not significantly different from that (average: 157.93 x mi) found in cells with five fragments. This was not the case for the average DNA content per fragment, which proved to be significantly lower in the latter cells (31.59 x mi versus 38.65 x mi).