Didinium captures Paramecium. A moment after initial contact when toxicysts enter Paramecium. The strand of toxicysts can be seen between the two organisms, and Didinium will use the anchored toxicysts to reel in Paramecium to the awaiting proboscis which is opening to accept its prey. The opening of the proboscis might be seen better in the same pair taken at a slightly different angle (CIL:21993). Also showing metachronous waves of cilia within the two characteristic ciliary girdles of Didinium nasutum; the waves on Paramecium may be paralyzed due to the effects of the attached toxicysts. This micrograph was taken in 1968 by G. Antipa on a Cambridge Mark IIA operating at 20kV. The negative magnification is 495X. Further details are available at Wessenberg, H. and Antipa, G. 1970. Capture and ingestion of Paramecium by Didinium nasutum. J. Protozool. 17:250-270.
Biological Process: Phagocytosis, Phagocytosis, engulfment
Author: Gregory Antipa (San Francisco State University)
Source: The Cell: An Image Library