Behavior and DNA synthesis of the nuclei produced after meiosis in Paramecium caudatum

Copyright © 1992 Gustav Fischer Verlag · Stuttgart · Jena · New York. Published by Elsevier GmbH.. All rights reserved..

Haploid micronuclei produced by meiosis in Paramecium caudatum are destined either to survive or to degenerate depending upon their position in the cytoplasm. The behavior of the four meiotic division products in living cells and their DNA synthesis patterns were examined to determine whether there were differences between nuclei destined to survive and those destined for degeneration. Some prospective degenerating nuclei divided, as did the surviving nuclei, but then became pycnotic immediately after division. This indicates that division and pycnosis are not alternative nuclear fates, but are independent processes. Microspectrophotometric measurements of DNA content showed that each meiotic product had 1 C amount of DNA at the second meiotic telophase and then increased the amount to 2 C linearly with time after the telophase. The time course of the DNA synthesis in the prospective degenerating nuclei was not different from that in the surviving ones. These results suggest that the determination of survival or degeneration of meiotic products is a process independent of division and DNA replication. But spindles and daughter nuclei of prospective degenerating nuclei showed some morphological differences from those of surviving ones. Furthermore, the degenerating nuclei became indistinct and small at the beginning of the degeneration, whereas this change was not observed in the surviving ones. Most of the surviving nuclei were surrounded by a clear region of the cytoplasm before their division. These morphological differences between the prospective surviving and degenerating nuclei may be related to their eventual outcomes.

Medienart:

E-Artikel

Erscheinungsjahr:

1992

Erschienen:

1992

Enthalten in:

Zur Gesamtaufnahme - volume:28

Enthalten in:

European journal of protistology - 28(1992), 1 vom: 21. Feb., Seite 37-42

Sprache:

Englisch

Beteiligte Personen:

Yanagi, A [VerfasserIn]

Links:

Volltext

Themen:

Journal Article

Anmerkungen:

Date Completed 03.12.2012

Date Revised 30.11.2012

published: Print-Electronic

Citation Status PubMed-not-MEDLINE

doi:

10.1016/S0932-4739(11)80317-2

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM223015962