Culture of cells at perfluorocarbon-aqueous interfaces

Protoplasts (wall-less cells) isolated enzymatically from leaf tissues of Manihot esculenta, Passiflora edulis and Petunia parodii, and from cell suspensions of Oryza sativa, Passiflora giberti, Petunia hybrida and Salpiglossis sinuata, were cultured for up to 35 d at an interface between the inert, oxygen-gassed perfluorocarbon (PFC) liquid, perfluorodecalin, overlaid with liquid or semi-solidified aqueous media. The maximum increase in mitotic division, as assessed by initial plating efficiency (IPE) occurred with protoplasts of O. sativa, which showed a 4-fold increase above the control over 35 d. Similar, but less pronounced increases in IPE of 90-103% occurred with S. sinuata, P. giberti and P. parodii following culture with oxygenated PFC. The least responsive species was M. esculenta, where the mean IPE after 25 d was increased by 33% over control. For those totipotent protoplast systems (e.g. P. edulis, P. giberti, O. sativa and P. parodii) phenotypically normal plants were regenerated following initial culture with oxygenated PFC. The advantages of such an interface system include (1) ease of sterilisation of the PFC by autoclaving, (2) the recycleability and, hence, recovery of the PFC, thereby offsetting the high initial costs, and (3) the ability to aspirate cells at the interface.