Euplotes focardii

Two diterpenoids, focardin (Structure 7.171) and an epoxide derivative (Structure 7.172), are produced by the marine ciliate Euplotes focardii, collected from Ross Sea coastal waters.195 Focardin is autotoxic and inhibits other ciliates, including one sympatric species, suggesting they are present... 

Scarce resources, such as food or space, in some marine environments can lead to production of compounds for the offensive role of reducing competition. Focardin (Structure 7.171) and its 11,12-epoxide (Structure 7.172), produced by the Antarctic ciliate Euplotes focardii, are autotoxic and cytotoxic toward a sympatric ciliate and a selection of temperate and tropical predatory ciliates.195... 

Guella, G., Dini, F., and Pietra, F., Epoxyfocardin and its putative biogenic precursor, focardin, bioactive, new-skeleton diterpenoids of the marine ciliate Euplotes focardii from Antarctica, Helv. Chim. Acta, 79, 439, 1996. 

Diterpenes are currently represented among ciliates by two compounds, focardin and epoxyfocardin, both isolated from cultures of the species Euplotes focardii, collected from the Italian Antarctic base located on the Ross Sea. Like the previous derivatives, these diterpenes are toxic to other species of ciliates and could therefore be used for chemical defense by E. focardii (Guella, Dini, and Pietra, 1996b). Currently, no more lactones seem to have been found in ciliates, but it is interesting to note that the carbon skeleton of focardin and its epoxy is an isoprenolog of that of rarisetenolide - both are mixtures of epimers. 

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