Cryopreservation is today one of the most accepted and promising techniques for the long-term maintenance of biological material at very low temperatures, offering the possibility of thawing it, and making it survive the freezing and thawing processes. The application of these techniques for preserving organisms could have unsuspected limits, especially in the future, also in the field of aquaculture, where their application could represent a revolution. This is argued by the team of specialists who, led by researcher Estefanía Paredes, work from the Toralla Marine Science Station, Ecimat, in the research of cryopreservation protocols under the auspices of the European project Assemble+. Cryopreservation is today one of the most accepted and promising techniques for the long-term maintenance of biological material at very low temperatures, offering the possibility of thawing it, and making it survive the freezing and thawing processes. The application of these techniques for preserving organisms could have unsuspected limits, especially in the future, also in the field of aquaculture, where their application could represent a revolution. This is argued by the team of specialists who, led by researcher Estefanía Paredes, work from the Toralla Marine Sciences Station, Ecimat, in the research of cryopreservation protocols under the auspices of the European project Assemble+.
They focus their work on the conservation of commercial species and of interest in aquaculture of marine invertebrates in the Galician area, especially echinoderms and molluscs, and the main objective is, as they explain, to achieve the implementation of this type of techniques in this sector, a priority in Galicia, to promote its development and increase its competitive capacity. They work with species that have never been used in cryopreservation experiments, among others, the mussel Mytilus galloprovincialis or the clam Venerupis corrugata.
Techniques that could solve many of the problems facing the industry
The application of cryopreservation techniques to aquaculture would solve many of the problems that this industry currently faces. “For example, individuals of a given species could be obtained at any time of the year,” explains Pablo Heres, one of the group’s researchers. “This would be very interesting, especially for species that have a seasonal reproductive cycle. Cryopreservation of adult individuals or even gametes or embryos would allow specimens to be obtained at any time, according to need or demand,” emphasizes Heres. They emphasize that this could be very useful in the trade of mollusc species, such as mussels or clams, and could even eliminate the impossibility of obtaining the product due to the appearance of red tides or scarcity in the natural environment. “Ultimately, a sustainable source of biological resources would be obtained,” they emphasize.
Furthermore, they explain, individuals could be selected that better withstand the conditions of intensive cultivation or that possess certain conditions that are of interest, either for applications in the biotechnological or molecular research sector, allowing the possibility of obtaining descendants over a very long period of time through their cryopreservation, thereby extending their lifespan. “Taking into account an ecological and conservationist point of view, cryopreservation could play a fundamental role in the conservation of threatened species, contributing to preventing their extinction,” Heres emphasizes.
How can you freeze animals and ‘revive’ them?
When asked how animals can be frozen and “revived”, the Ecimat team explains that this is achieved by using chemical substances that are capable of protecting the cells throughout the process, called cryoprotectants. “These compounds prevent the formation of ice crystals inside the cells, which could be lethal”, explains the researcher.
The complexity of developing a protocol that serves to cryopreserve a type of cells of a given species is marked, the researchers highlight, by a series of stages, with which the aim is to establish the optimal conditions for their preservation at very low temperatures. The first of these consists of selecting the cryoprotectant that has the most protective effect, since not all chemicals established as such have the same effect on all cells, but rather their protective effect against freezing varies depending on the cell type, and even between species. “These differences in their function are due to the fact that the cryoprotectant must cross the cell membrane to perform its cryoprotection function. As cell membranes are different depending on the function of the cell and organism that they compose, the cryoprotectant agent has more or less difficulty crossing this membrane”, explains Heres. On the other hand, not only must the best chemical substance that protects a given organism or cell be chosen, but also its concentration, since if it is too high it can be lethal. “Therefore, initially, its toxicity is evaluated by determining the effect of different concentrations on the survival of cells or organisms after subjecting them to freezing experiments. “Finally, that cryoprotectant that offers greater survival and a lower toxic effect is selected”, emphasizes the researcher.
Source: DUVI
