title: Morphological apoptotic characteristics of the post-meiotic micronuclei in Paramecium caudatum.
abstract: In a previous study, the apoptotic degeneration of meiotic products outside the paroral region of Paramecium caudatum was indirectly demonstrated by means of "apofluor" staining. In this experiment, conjugating pairs and exconjugants of P. caudatum were stained with either "apofluor" or carbol fuchsin or both to find some direct evidence to demonstrate the apoptotic characteristics of this process. As a result, asynchronous meiotic nuclear degeneration was observed. Furthermore, a number of additional meiotic nuclei were found. Disintegrating/dividing meiotic nuclei outside the paroral region were observed, which might be the origin of these additional meiotic nuclei. Condensed chromatin and disintegrated chromatin attached to the nuclear membrane were also observed in degenerating nuclei, which are the typical morphological characteristics of apoptosis. Comparison of the cells stained by the above two methods indicated that "apofluor"-stained meiotic nuclei could not be detected by carbol fuchsin in some cells, which suggests a time lag between meiotic nuclear DNA degradation and their eventual disappearance. In this study, some direct evidence was found to show that the meiotic nuclear degeneration in P. caudatum is of apoptotic nature, which further confirmed our previous study (Yang et al. 2007) and indicated that morphological apoptotic characteristics discovered in multicellular organisms do exist in unicellular eukaryotic ciliate protozoa.
authors.affiliation: School of Forestry and Biotechnology, Zhejiang Argriculture and Forestry University, 88 Huancheng Beilu, Lin'An Zhejiang 311300, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Gao
authors.forename: Xinjiong
authors.initials: X
authors.lastname: Zhang
authors.forename: Xianyu
authors.initials: X
authors.lastname: Yang
mesh_terms: D017209:Apoptosis; D002467:Cell Nucleus / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism; D016054:DNA, Protozoan / Q000378:metabolism*; D005456:Fluorescent Dyes / Q000378:metabolism; D008540:Meiosis; D048488:Paramecium caudatum / Q000166:cytology*; D012394:Rosaniline Dyes / Q000378:metabolism; D013194:Staining and Labeling
chemical_list: D002843:Chromatin; D016054:DNA, Protozoan; D005456:Fluorescent Dyes; D012394:Rosaniline Dyes; C006898:carbol-fuchsin solution