A leech capable of surviving exposure to extremely low temperatures
Physiology study published in PLoS ONE (2014)
Abstract
It is widely considered that most organisms cannot survive prolonged exposure to temperatures below 0°C, primarily because of the damage caused by the water in cells as it freezes. However, some organisms are capable of surviving extreme variations in environmental conditions. In the case of temperature, the ability to survive subzero temperatures is referred to as cryobiosis. We show that the ozobranchid leech, Ozobranchus jantseanus, a parasite of freshwater turtles, has a surprisingly high tolerance to freezing and thawing. This finding is particularly interesting because the leach can survive these temperatures without any acclimation period or pretreatment. Specifically, the leech survived exposure to super-low temperatures by storage in liquid nitrogen (-196°C) for 24 hours, as well as long-term storage at temperatures as low as -90°C for up to 32 months. The leech was also capable of enduring repeated freeze-thaw cycles in the temperature range 20°C to -100°C and then back to 20°C. The results demonstrated that the novel cryotolerance mechanisms employed by O. jantseanus enable the leech to withstand a wider range of temperatures than those reported previously for cryobiotic organisms. We anticipate that the mechanism for the observed tolerance to freezing and thawing in O. jantseanus will prove useful for future studies of cryopreservation.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
Demonstrates Ozobranchus jantseanus leech survival at extremely low temperatures (-196°C) — exceptional cold tolerance relevant to ASH storage and shipping protocols.
Why This Matters for Hirudotherapy
This study demonstrated that the freshwater turtle leech Ozobranchus jantseanus has remarkable cryotolerance, surviving storage in liquid nitrogen (-196°C) for 24 hours, long-term storage at -90°C for up to 32 months, and repeated freeze-thaw cycles between 20°C and -100°C, all without acclimation or pretreatment. The authors suggest the underlying cryotolerance mechanisms may inform future cryopreservation research. While this concerns a leech species, O. jantseanus is a turtle ectoparasite with no established role in medicinal hirudotherapy. Its relevance to ASH's domain is indirect, limited to basic comparative biology of leeches rather than therapeutic applications of the leech secretome.
Citation
A leech capable of surviving exposure to extremely low temperatures.
Suzuki D et al. · PloS one, 2014
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