Calcium-regulated fusion of yolk granules is important for yolk degradation during early embryogenesis of Rhodnius prolixus Stahl.
J Exp Biol
; 210(Pt 1): 138-48, 2007 Jan.
Article
em En
| MEDLINE
| ID: mdl-17170157
ABSTRACT
This study examined the process of membrane fusion of yolk granules (YGs) during early embryogenesis of Rhodnius prolixus. We show that eggs collected at days 0 and 3 after oviposition contain different populations of YGs, for example day-3 eggs are enriched in large YGs (LYGs). Day-3 eggs also contain the highest free [Ca(2+)] during early embryogenesis of this insect. In vitro incubations of day-0 YGs with [Ca(2+)] similar to those found in day-3 eggs resulted in the formation of LYGs, as observed in vivo. Fractionation of LYGs and small YGs (SYGs) and their subsequent incubation with the fluorescent membrane marker PKH67 showed a calcium-dependent transference of fluorescence from SYGs to LYGs, possibly as the result of membrane fusion. Acid phosphatase and H(+)-PPase activities were remarkably increased in day-3 LYGs and in calcium-treated day-0 LYGs. Both fractions were found to contain vitellins as major components, and incubation of YGs with calcium induced yolk proteolysis in vitro. Altogether, our results suggest that calcium-induced membrane fusion events take part in yolk degradation, leading to the assembly of the yolk mobilization machinery.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Óvulo
/
Rhodnius
/
Cálcio
Limite:
Animals
Idioma:
En
Revista:
J Exp Biol
Ano de publicação:
2007
Tipo de documento:
Article