ISSN:
1615-6102
Keywords:
Cyclopiazonic acid
;
Golgi apparatus
;
Micrasterias
;
Secretory pathway
;
Tunicamycin
;
Ultrastructure
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Both tunicamycin, an inhibitor of N-linked glycosylation of proteins, and cyclopiazonic acid, which inhibits the Ca2+-dependent ATPase in the ER, influence the secretory pathway at the ER level and lead to a cessation of cell growth inMicrasterias. Electron microscopical investigations reveal that the mode of action of the two inhibitors differs. While tunicamycin treatment results in a disintegration of the Golgi bodies into small vesicles, cyclopiazonic acid prevents products being supplied from the ER, resulting in the dilatation of ER cisternae and a reduction in the number of Golgi cisternae, combined with a loss of dictyosomal activity. The disturbed cell wall formation under tunicamycin indicates that N-linked glycosylation of proteins is required for normal cell growth inMicrasterias. Moreover, our studies reveal that changes in cytoplasmic free calcium concentration, as a consequence of ATPase inhibition in the ER by cyclopiazonic acid, may inhibit wall material secretion by interrupting the normal ER-dictyosome association.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01280171
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