Ca2+-dependent contractility of isolated and demembranated macronuclei in the hypotrichous ciliate Euplotes aediculatus.
Cell Calcium
; 33(2): 113-7, 2003 Feb.
Article
em En
| MEDLINE
| ID: mdl-12531187
ABSTRACT
The hypotrichous ciliated protozoan Euplotes aediculatus possesses a characteristic C-shaped somatic nucleus (macronucleus) within the cytoplasm, which shows dynamic shape change during the cell cycle. It is shown that isolated macronuclei possess Ca(2+)-dependent contractility. Macronuclei were isolated, stuck fast on the glass surface, and subjected to different concentrations of Ca(2+) in a Ca(2+)-EGTA buffer. The nuclei became expanded at [Ca(2+)]<10(-7)M, and they contracted on subsequent addition of higher concentrations of Ca(2+). Cycles of expansion and contraction of the nucleus could be repeated many times by alternate addition of EGTA and Ca(2+), indicating that the size of isolated nuclei can be regulated by [Ca(2+)] alone. The nuclear contraction was observed in all phases of the cell cycle, but contractility was less evident around replication bands in the S phase. In addition to the hypotrichous ciliate Euplotes, similar Ca(2+)-dependent nuclear contractility was found to exist in other cell types, including protozoans of different taxa (a heliozoon Actinophrys sol and a peniculine ciliate Paramecium bursaria), and also mammalian culture cells (HeLa cells). Our findings suggest a possibility that Ca(2+)-dependent nuclear contractility may be shared among diverse eukaryotic organisms.
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Base de dados:
MEDLINE
Assunto principal:
Movimento Celular
/
Núcleo Celular
/
Cálcio
/
Euplotes
/
Sinalização do Cálcio
/
Citoplasma
Limite:
Animals
/
Humans
Idioma:
En
Ano de publicação:
2003
Tipo de documento:
Article