Egg activation inPimpla turionellae (Hym.)

Modulation of MAPK Activities During Egg Activation in Drosophila

“…1C and D). We detected phospho-ERK in early (stages 1-10) oocytes at levels comparable to older (stages [11][12][13][14] oocytes (data not shown). Having confirmed that we can detect MAP kinases by this method in oocytes, and given their potential involvement in egg activation, we examined MAPK and active (phospho-) MAPK levels in activated eggs and embryos.…”

“…1 However, in the four insects examined to date (Drosophila and three wasps), fertilization is not needed for egg activation; instead, activation appears to be triggered by stimuli imparted to the ovulated egg as it passes through the reproductive tract. 2,[9][10][11] Recent studies have shown that, despite this difference in initial trigger, many of the downstream activation events in Drosophila including a requirement for calcium signaling 3,12 are analogous to those in other animals. Drosophila can thus serve as a model in which to identify the genes that regulate activation.…”

Transitioning from egg to embryo: Triggers and mechanisms of egg activation

“…This has been experimentally validated: when P. turionellae eggs dissected from the ovary are squeezed through a narrow capillary tube, over 70% of eggs activate, as measured by their ability to develop into male larvae ( Fig. 1B; Went and Krause, 1974). In another example of mechanical stress triggering egg activation, 23% of eggs dissected from ovaries of the haplodiploid wasp, Nasonia vitripennis, and pressed with a needle were able to develop to larvae (King and Rafai, 1970).…”

“…B: Mechanical stimulation triggers egg activation in some insects. In Pimpla turionellae (reprinted with permission from the homepage of ETH Applied Entomology Group: http://www.em.ipw.agrl.ethz.ch/), passage of the oocyte through the ovipositor (red box) during egg laying can be imitated by pressing eggs dissected from the ovary (a) through a capillary tube (b) (Went and Krause, 1974). This mechanical cue stimulates development (c) [reprinted from Went and Krause (1974) with permission from Macmillan Publishers Ltd. http://www.nature.com/index.html].…”

“…In Pimpla turionellae (reprinted with permission from the homepage of ETH Applied Entomology Group: http://www.em.ipw.agrl.ethz.ch/), passage of the oocyte through the ovipositor (red box) during egg laying can be imitated by pressing eggs dissected from the ovary (a) through a capillary tube (b) (Went and Krause, 1974). This mechanical cue stimulates development (c) [reprinted from Went and Krause (1974) with permission from Macmillan Publishers Ltd. http://www.nature.com/index.html]. In Drosophila melanogaster, movement of oocytes from the ovary into the small and tight oviducts triggers egg activation (Heifetz et al, 2001) [reprinted from Heifetz et al (2001), with permission from Elsevier].…”