Transformation of PbCTRP-KO ookinetes in Anopheles gambiae. Phase contrast image of a PbCTRP-KO oocyst (arrow) attached to the midgut of An. gambiae KIL mosquito. The trachea (arrow heads) and Malpighian tubules (MT) are also shown. Plasmodium berghei CTRP-KO ookinetes were injected 18 h post-culture into the haemocoel of 4-day old An. gambiae KIL females and allowed to develop for 7 days prior to mosquito dissection.