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Natural Ice-Nucleating Bacteria Increase The Freezing Tolerance Of The Intertidal Bivalve Geukensia Demissa, Alexander M. Mccorkle

Biology Honors Papers

Instead of avoiding freezing, freeze tolerant invertebrates actively initiate controlled ice nucleation at relatively high sub-zero temperatures in extracellular compartments. Most produce proteinaceous ice-nucleators in their hemolymph, however the intertidal bivalve mollusc Geukensia demissa lacks this ability. Instead it utilizes at least one strain of ice-nucleation active (INA) bacteria, Pseudomonas fulva, present in seawater, to induce crystallization in the pallial fluid that fills its mantle cavity. In this study, two additional INA bacteria strains were isolated from the palial fluid of Geukensia demissa: Psychrobacter sp. and Shewanella sp. The ice-nucleation activity of both strains was characterized and Psychrobacter was found …