Cryopreservation of a Thermotolerant Lineage of the Coral Reef Dinoflagellate .

Dinoflagellates of the genus form symbiotic relationships with corals, other marine invertebrates, and protists; thus, they are considered as important species in coral reef ecosystems. If could be successfully cryopreserved, the cell bank generated could prove to be a valuable resource for researchers interested in basic biological research of -invertebrate symbioses. Herein, successful cryopreservation of clade D was achieved using a two-step freezing protocol. cells were exposed to cryoprotectants (CPAs) for 30 minutes before being vapor frozen for 20 minutes in liquid nitrogen (LN); afterward, cells were immediately immersed in LN for 2 hours or 10 days. The initial experiment was conducted with the following CPAs at 1, 2, and 3 M concentrations: methanol, dimethyl sulfoxide, glycerol, ethylene glycol (EG), and propylene glycol (PG). It was found that infiltration with 2 M EG and PG yielded cells with the highest percentage viability. Upon thawing, culture of these was carried out for 2 months in a growth chamber, and cells continued to grow and proliferate over this period. This represents successful cryopreservation of a dominant reef coral symbiont, a feat that will ideally aid in future research of this important lineage of dinoflagellate.