[1] In the related process of kleptoplasty, the predator sequesters plastids (especially chloroplasts) from dietary algae.
The chloroplasts can still photosynthesize, but do not last long after the prey's cells are metabolised.
If the predator can also sequester cell nuclei from the prey to encode proteins for the plastids, it can sustain them.
Johnson et al. described and named karyoklepty in 2007 after observing it in the ciliate species Mesodinium rubrum.
[1] Karyoklepty is a Greek compound of the words karydi ("kernel") and kleftis ("thief").