<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hi Richard, <div class=""><br class=""></div><div class="">I have experienced the similar situation, and it could also be due to “bad” sperms, i.e., they may have activated eggs so that you can see pigment contraction but no fertilization actually happened. When I changed a male (i.e., used new testes), the same eggs could be fertilized. If you happen to have <i class="">laevis </i>eggs when you use trop, you can also test if those sperms make <i class="">laevis </i>eggs fertilized (cleaved), then you can tell if the problem is bad eggs or bad sperms.</div><div class="">Thanks.</div><div class=""><br class=""></div><div class="">Takuya</div><div><br class=""><blockquote type="cite" class=""><div class="">On Oct 22, 2020, at 14:47, Richard Harland <<a href="mailto:harland@berkeley.edu" class="">harland@berkeley.edu</a>> wrote:</div><br class="Apple-interchange-newline"><div class="">
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class=""><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span style="font-size: 11pt;" class="">Our use of trops declined to zero over the COVID period, and now they often produce good looking eggs, which appear to fertilize (polar body extrusion), but then all but a couple fail to cleave. We are cycling them through ovulation to hope for better eggs next time, and ordering some more from the excellent NXR. But do others have this experience, and is there a short cut to healthy eggs?</span></div></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span style="font-size: 11pt;" class="">thanks</span></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span style="font-size: 11pt;" class="">Richard</span></div></div>_______________________________________________<br class="">Xenopus mailing list<br class=""><a href="mailto:Xenopus@lists.mbl.edu" class="">Xenopus@lists.mbl.edu</a><br class="">https://lists.mbl.edu/mailman/listinfo/xenopus<br class=""></div></blockquote></div><br class=""></body></html>