A secondary symbiosis in progress?

Entrez PubMed: "Algae have acquired plastids by developing an endosymbiotic relationship with either a cyanobacterium (primary endosymbiosis) or other eukaryotic algae (secondary endosymbiosis). We report a protist, which we tentatively refer to as Hatena, that hosts an endosymbiotic green algal partner but inherits it unevenly. The endosymbiosis causes drastic morphological changes to both the symbiont and the host cell architecture. This type of life cycle, in which endosymbiont integration has only partially converted the host from predator to autotroph, may represent an early stage of plastid acquisition through secondary symbiosis."

Okamoto N, Inouye I. A secondary symbiosis in progress? Science. 2005 Oct 14;310(5746):287.

You can find a good image here, and a concise commentary on the Science article here.