Apoptotic cell death and cellular surface negative charge increase in maize roots exposed to cytotoxic stresses

Citation
Sb. Ning et al., Apoptotic cell death and cellular surface negative charge increase in maize roots exposed to cytotoxic stresses, ANN BOTANY, 87(5), 2001, pp. 575-583
Citations number
38
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Plant Sciences
Journal title
ANNALS OF BOTANY
ISSN journal
0305-7364 → ACNP
Volume
87
Issue
5
Year of publication
2001
Pages
575 - 583
Database
ISI
SICI code
0305-7364(200105)87:5<575:ACDACS>2.0.ZU;2-J
Abstract
Maize root meristematic tissues were exposed to cytotoxic reagents, the RNA -synthesis inhibitor Actinomycin D (ActD), the protein-synthesis inhibitor cycloheximide (CHX) and the mitosis inhibitor colchicine (COL). Morphologic al and biochemical evidence of specific apoptotic nuclei and chromosomes in individual treated cells was identified using a simple and highly efficien t chromosome spreading-based TUNEL assay, DNA laddering and DNA gel blottin g. All of these drugs induced DNA cleavage, dose-dependent oligomeric ladde rs, and characteristic nuclear and chromosomal condensations. Results from DNA gel blotting showed that DNA ladders could be induced by exposure to 0. 1 mg l(-1) ActD, 100 mg l(-1) CHX and 500 mg l(-1) COL for 6 h, 6 h and 12 h respectively. The sequence of changes in single cells was studied in deta il. DNA cleavage was found to occur before condensation and disorganization of the nucleus, followed by deformation and condensation of metaphase chro mosomes, and marginalization of chromatin. Finally, nucleoli disappeared an d fragmentation of the nucleus occurred. Meanwhile, changes in the outer su rface charge of apoptotic cells were assessed by electrophoresis. Results i ndicated quantitatively that the surface negative charge increased during t hese apoptotic processes. Our results also showed that the apoptotic pathwa y induced by each of these drugs could be reversed before serious cleavage of DNA into oligonucleosomal fragments and universal chromatin condensation . (C) 2001 Annals of Botany Company.