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Seasonal Preservation Success of the Marine Dinoflagellate Coral Symbiont, Symbiodinium sp.

Hagedorn M, Carter VL - PLoS ONE (2015)

Bottom Line: Only the ultra-rapid procedure called vitrification resulted in success whereas conventional slow freezing protocols did not.Additionally, there also was a seasonal influence on vitrification success as the best post-thaw survival of F. scutaria occurred in winter and spring compared to summer and fall (P < 0.05).These findings lay the foundation for developing a viable genome resource bank for the world's Symbiodinium that, in turn, will not only protect this critical element of coral functionality but serve as a resource for understanding the complexities of symbiosis, support selective breeding experiments to develop more thermally resilient strains of coral, and provide a 'gold-standard' genomics collection, allowing for full genomic sequencing of unique Symbiodinium strains.

View Article: PubMed Central - PubMed

Affiliation: Department of Reproductive Sciences, Smithsonian Conservation Biology Institute- National Zoological Park, Front Royal, VA, United States of America; Hawai'i Institute of Marine Biology, University of Hawaii, Kaneohe, HI, United States of America.

ABSTRACT
Coral reefs are some of the most diverse and productive ecosystems on the planet, but are threatened by global and local stressors, mandating the need for incorporating ex situ conservation practices. One approach that is highly protective is the development of genome resource banks that preserve the species and its genetic diversity. A critical component of the reef are the endosymbiotic algae, Symbiodinium sp., living within most coral that transfer energy-rich sugars to their hosts. Although Symbiodinium are maintained alive in culture collections around the world, the cryopreservation of these algae to prevent loss and genetic drift is not well-defined. This study examined the quantum yield physiology and freezing protocols that resulted in survival of Symbiodinium at 24 h post-thawing. Only the ultra-rapid procedure called vitrification resulted in success whereas conventional slow freezing protocols did not. We determined that success also depended on using a thin film of agar with embedded Symbiodinium on Cryotops, a process that yielded a post-thaw viability of >50% in extracted and vitrified Symbiodinium from Fungia scutaria, Pocillopora damicornis and Porites compressa. Additionally, there also was a seasonal influence on vitrification success as the best post-thaw survival of F. scutaria occurred in winter and spring compared to summer and fall (P < 0.05). These findings lay the foundation for developing a viable genome resource bank for the world's Symbiodinium that, in turn, will not only protect this critical element of coral functionality but serve as a resource for understanding the complexities of symbiosis, support selective breeding experiments to develop more thermally resilient strains of coral, and provide a 'gold-standard' genomics collection, allowing for full genomic sequencing of unique Symbiodinium strains.

No MeSH data available.


Schematic of cryopreservation methods used in all these experiments in this study.
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pone.0136358.g001: Schematic of cryopreservation methods used in all these experiments in this study.

Mentions: Cryotop (Kitazato Corporation, Tokyo, Japan) methods have been used to manipulate human oocytes for ultra-rapid warming to produce successful vitrification [40]. To determine the applicability of these devices to cryopreserving Symbiodinium, we used a 2-μl drop of zooxanthellae on the Cryotop (Experiment 1 only) or a 1.5 μl drop spread as a thin agar film the following four treatments with Symbiodinium embedded within as mentioned in Fig 1 (used in all other Experiments) melted on to the top of the Cryotop. Conditions (i.e. temperatures and times for embedding) are given below in part 2. With this agar-and-Symbiodinium film method, the Symbiodinium did not fall off during the passage from solution-to-solution and during freezing or culture because they were embedded within the agar, making Symbiodinium manipulations easier. The conditions (i.e. temperatures and times for embedding) are given below in part 2. The agar-and-Symbiodinium film covered an area of the Cryotop approximately 0.5 cm in length from the tip of the Cryotop surface and had a domed shape (see schematic in Fig 1). During these protocols, Symbiodinium health was assessed after loading into agar and onto a Cryotops and then again during certain intervals post-thaw. Cryotops samples were moved through solutions and afterwards set into shallow dishes to await viability assessment with the PAM.


Seasonal Preservation Success of the Marine Dinoflagellate Coral Symbiont, Symbiodinium sp.

Hagedorn M, Carter VL - PLoS ONE (2015)

Schematic of cryopreservation methods used in all these experiments in this study.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4589415&req=5

pone.0136358.g001: Schematic of cryopreservation methods used in all these experiments in this study.
Mentions: Cryotop (Kitazato Corporation, Tokyo, Japan) methods have been used to manipulate human oocytes for ultra-rapid warming to produce successful vitrification [40]. To determine the applicability of these devices to cryopreserving Symbiodinium, we used a 2-μl drop of zooxanthellae on the Cryotop (Experiment 1 only) or a 1.5 μl drop spread as a thin agar film the following four treatments with Symbiodinium embedded within as mentioned in Fig 1 (used in all other Experiments) melted on to the top of the Cryotop. Conditions (i.e. temperatures and times for embedding) are given below in part 2. With this agar-and-Symbiodinium film method, the Symbiodinium did not fall off during the passage from solution-to-solution and during freezing or culture because they were embedded within the agar, making Symbiodinium manipulations easier. The conditions (i.e. temperatures and times for embedding) are given below in part 2. The agar-and-Symbiodinium film covered an area of the Cryotop approximately 0.5 cm in length from the tip of the Cryotop surface and had a domed shape (see schematic in Fig 1). During these protocols, Symbiodinium health was assessed after loading into agar and onto a Cryotops and then again during certain intervals post-thaw. Cryotops samples were moved through solutions and afterwards set into shallow dishes to await viability assessment with the PAM.

Bottom Line: Only the ultra-rapid procedure called vitrification resulted in success whereas conventional slow freezing protocols did not.Additionally, there also was a seasonal influence on vitrification success as the best post-thaw survival of F. scutaria occurred in winter and spring compared to summer and fall (P < 0.05).These findings lay the foundation for developing a viable genome resource bank for the world's Symbiodinium that, in turn, will not only protect this critical element of coral functionality but serve as a resource for understanding the complexities of symbiosis, support selective breeding experiments to develop more thermally resilient strains of coral, and provide a 'gold-standard' genomics collection, allowing for full genomic sequencing of unique Symbiodinium strains.

View Article: PubMed Central - PubMed

Affiliation: Department of Reproductive Sciences, Smithsonian Conservation Biology Institute- National Zoological Park, Front Royal, VA, United States of America; Hawai'i Institute of Marine Biology, University of Hawaii, Kaneohe, HI, United States of America.

ABSTRACT
Coral reefs are some of the most diverse and productive ecosystems on the planet, but are threatened by global and local stressors, mandating the need for incorporating ex situ conservation practices. One approach that is highly protective is the development of genome resource banks that preserve the species and its genetic diversity. A critical component of the reef are the endosymbiotic algae, Symbiodinium sp., living within most coral that transfer energy-rich sugars to their hosts. Although Symbiodinium are maintained alive in culture collections around the world, the cryopreservation of these algae to prevent loss and genetic drift is not well-defined. This study examined the quantum yield physiology and freezing protocols that resulted in survival of Symbiodinium at 24 h post-thawing. Only the ultra-rapid procedure called vitrification resulted in success whereas conventional slow freezing protocols did not. We determined that success also depended on using a thin film of agar with embedded Symbiodinium on Cryotops, a process that yielded a post-thaw viability of >50% in extracted and vitrified Symbiodinium from Fungia scutaria, Pocillopora damicornis and Porites compressa. Additionally, there also was a seasonal influence on vitrification success as the best post-thaw survival of F. scutaria occurred in winter and spring compared to summer and fall (P < 0.05). These findings lay the foundation for developing a viable genome resource bank for the world's Symbiodinium that, in turn, will not only protect this critical element of coral functionality but serve as a resource for understanding the complexities of symbiosis, support selective breeding experiments to develop more thermally resilient strains of coral, and provide a 'gold-standard' genomics collection, allowing for full genomic sequencing of unique Symbiodinium strains.

No MeSH data available.