Figure 3.

Effect of collagenase and acidified Tyrode's solution on the fragmented eggs. a Before collagenase treatment (control). b After collagenase treatment. c, d Two fragmented eggs before and after acidified Tyrode's solution treatment. Eggs shown in d are the same as those in c; images were taken immediately after eggs shown in c were transferred into acidified Tyrode's solution (d). a, b The ZP of the fragmented eggs (arrows in a and b) and some eggs that have normal morphology (arrowheads in b) were not removed by collagenase treatment. (c, d) The ZP of these two fragmented eggs became completely dissolved by acidified Tyrode's solution. Bars 100 μm