Folgueira López, IriaFelipe González, Ana Paula deSueiro Benavides, Rosa AnaLamas Fernández, JesúsLeiro Vidal, José Manuel2019-01-302019-01-302018-02Folgueira I, de Felipe AP, Sueiro RA, Lamas J, Leiro J. (2017). Protocol for cryopreservation of the turbot parasite Philasterides dicentrarchi (Ciliophora, Scuticociliatia). Cryobiology 80:77-83. doi: 10.1016/j.cryobiol.2017.11.0100011-2240http://hdl.handle.net/10347/18172This is the accepted manuscript of the following article: Folgueira, I., de Felipe, A.P., Sueiro, R.A., Lamas, J. & Leiro, J. (2018). Protocol for cryopreservation of the turbot parasite Philasterides dicentrarchi (Ciliophora, Scuticociliatia). Cryobiology, 80, 77-83. doi: 10.1016/j.cryobiol.2017.11.010Philasterides dicentrarchi is a free-living marine ciliate that can become an endoparasite that causes a severe disease called scuticociliatosis in cultured fish. Long-term maintenance of this scuticociliate in the laboratory is currently only possible by subculture, with periodic passage in fish to maintain the virulence of the isolates. In this study, we developed and optimized a cryopreservation protocol similar to that used for the long-term storage of scuticociliates of the genus Miamiensis. The cryogenic medium comprised ATCC medium 1651 and a combination of 11% dimethylsulfoxide and 5% glycerol. We have verified that the most important factor ensuring the efficiency of the cryopreservation procedure is the growth phase of the culture, and that ciliates should be cryopreserved at the stationary phase (around the sixth day of culture). The cryopreservation protocol described here can be used for all strains of P. dicentrarchi as well as commercial strains of Miamiensis and enables the virulence of the strains to be maintained. Finally, this cryopreservation protocol has been shown to be more effective than others routinely applied to scuticociliates, yielding a higher survival rate with a lower initial concentration of ciliates. The results obtained indicate that the cropreservation protocol enables the long-term storage of scuticociliate parasites while maintaining the virulence of the isolates. The protocol is therefore suitable for use in vaccine production and related studieseng© 2017 Elsevier B.V. This manuscript version is made available under the CC-BY-NC-ND 4.0 license (http://creativecommons.org/licenses/by-nc-nd/4.0/)http://creativecommons.org/licenses/by-nc-nd/4.0/Philasterides dicentrarchiMiamiensis avidusFreezingCryoprotectantsCryopreservationOptimizationjournal article10.1016/j.cryobiol.2017.11.010open access