title: When isolated at full receptivity, in vitro fertilized wheat (Triticum aestivum, L.) egg cells reveal [Ca2+]cyt oscillation of intracellular origin.
abstract: During in vitro fertilization of wheat (Triticum aestivum, L.) in egg cells isolated at various developmental stages, changes in cytosolic free calcium ([Ca2+]cyt) were observed. The dynamics of [Ca2+]cyt elevation varied, reflecting the difference in the developmental stage of the eggs used. [Ca2+]cyt oscillation was exclusively observed in fertile, mature egg cells fused with the sperm cell. To determine how [Ca2+]cyt oscillation in mature egg cells is generated, egg cells were incubated in thapsigargin, which proved to be a specific inhibitor of the endoplasmic reticulum (ER) Ca2+-ATPase in wheat egg cells. In unfertilized egg cells, the addition of thapsigargin caused an abrupt transient increase in [Ca2+]cyt in the absence of extracellular Ca2+, suggesting that an influx pathway for Ca2+ is activated by thapsigargin. The [Ca2+]cyt oscillation seemed to require the filling of an intracellular calcium store for the onset of which, calcium influx through the plasma membrane appeared essential. This was demonstrated by omitting extracellular calcium from (or adding GdCl3 to) the fusion medium, which prevented [Ca2+]cyt oscillation in mature egg cells fused with the sperm. Combined, these data permit the hypothesis that the first sperm-induced transient increase in [Ca2+]cyt depletes an intracellular Ca2+ store, triggering an increase in plasma membrane Ca2+ permeability, and this enhanced Ca2+ influx results in [Ca2+]cyt oscillation.
authors.affiliation: Department of Plant Production and Plant Protection, Institute of Plant Science, Faculty of Agricultural and Environmental Sciences, Kaposvár University, Kaposvár H-7400, Hungary. ponyazs@yahoo.com.
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Pónya
authors.affiliation: Dipartimento di Scienze Ambientali "G. Sarfatti", University of Siena, Siena 53100, Italy. ilaria.corsi@unisi.it.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Corsi
authors.affiliation: Department of Plant Production and Plant Protection, Institute of Plant Science, Faculty of Agricultural and Environmental Sciences, Kaposvár University, Kaposvár H-7400, Hungary. hoffmann.richard@ke.hu.
authors.forename: Richárd
authors.initials: R
authors.lastname: Hoffmann
authors.affiliation: Institute of Physiology, Biochemistry and Animal Health, Faculty of Agricultural and Environmental Sciences, Kaposvár University, Kaposvár H-7400, Hungary. kovacs.melinda@ke.hu.
authors.forename: Melinda
authors.initials: M
authors.lastname: Kovács
authors.affiliation: Department of Plant Production and Plant Protection, Institute of Plant Science, Faculty of Agricultural and Environmental Sciences, Kaposvár University, Kaposvár H-7400, Hungary. aniko.dobosy@esolution.hu.
authors.forename: Anikó
authors.initials: A
authors.lastname: Dobosy
authors.affiliation: Department of Technology of Animal Breeding and Management, Faculty of Agricultural and Environmental Sciences Kaposvár University, Kaposvár H-7400, Hungary. kovacs.attila@ke.hu.
authors.forename: Attila Zoltán
authors.initials: AZ
authors.lastname: Kovács
authors.affiliation: Dipartimento di Scienze Ambientali "G. Sarfatti", University of Siena, Siena 53100, Italy. cresti@unis.it.
authors.forename: Mauro
authors.initials: M
authors.lastname: Cresti
authors.affiliation: Department of Plant Cell Biology, Agricultural Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Martonvàsàr H-2462, Hungary. barnabas.beata@agrar.mta.hu.
authors.forename: Beáta
authors.initials: B
authors.lastname: Barnabás
mesh_terms: D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects; D005307:Fertilization in Vitro / Q000379:methods; D042541:Intracellular Space / Q000378:metabolism; D007783:Lactones / Q000494:pharmacology; D057054:Molecular Imaging; D012717:Sesquiterpenes / Q000494:pharmacology; D014908:Triticum / Q000378:metabolism*
chemical_list: D007783:Lactones; D012717:Sesquiterpenes; C046319:thapsigargicin; D002118:Calcium