Injection of a cumulus cell nucleus into an enucleated oocyte. (A) Dispersed cumulus cells; (B) cumulus cell nuclei (arrowheads) in injection pipette; (C) piercing the zona pellucida with the injection pipette; (D) pushing the injection pipette deep into the enucleated oocyte but not breaking the oolemma. (E) Application of the piezo pulse breaks the oolemma, causing a visual relaxation of the membrane (cf. the lengths of the double arrows in D and E). (F) Injection of the donor cumulus cell nucleus (arrowhead) into the ooplasm.