Euglena gracilis green cells were treated for 1-5 min with 0.5-1 mM tetracaine (TC), a local anaesthetic known to displace membrane-bound calcium. One or 2 min exposure was sufficient to stop cell motility, induce cell rounding and alter the main organelles, except for the nucleus. The chloroplasts became irregularly shaped and displayed dilated locula; the mitochondria and Golgi apparatus lost their normal morphology; the reservoir microtubules (MTs) disappeared, whereas pellicular and flagellar MTs were unmodified. After 5 min treatment, mitochondria and plastids aggregated in clusters. In the nucleus, the chromatinic masses were fewer and smaller than normal and the nucleoplasm was infiltrated by inclusions of uncertain nature. The observed alterations suggest that TC alters the network which motility and scaffolding to both cytoplasmic and nuclear structures. Such effects may be interpreted in terms of increased intracellular Ca2+ even if additional mechanisms of action of the molecule cannot be excluded.
Ultrastructural effects of tetracaine in Euglena gracilis
VANNINI, Gian Luigi;POLI, Ferruccio;PANCALDI, Simonetta;FASULO, Maria Palmira
1988
Abstract
Euglena gracilis green cells were treated for 1-5 min with 0.5-1 mM tetracaine (TC), a local anaesthetic known to displace membrane-bound calcium. One or 2 min exposure was sufficient to stop cell motility, induce cell rounding and alter the main organelles, except for the nucleus. The chloroplasts became irregularly shaped and displayed dilated locula; the mitochondria and Golgi apparatus lost their normal morphology; the reservoir microtubules (MTs) disappeared, whereas pellicular and flagellar MTs were unmodified. After 5 min treatment, mitochondria and plastids aggregated in clusters. In the nucleus, the chromatinic masses were fewer and smaller than normal and the nucleoplasm was infiltrated by inclusions of uncertain nature. The observed alterations suggest that TC alters the network which motility and scaffolding to both cytoplasmic and nuclear structures. Such effects may be interpreted in terms of increased intracellular Ca2+ even if additional mechanisms of action of the molecule cannot be excluded.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
