In the fall, freeze tolerant intertidal invertebrates usually produce ice-nucleating proteins that are secreted into the hemolymph. These proteins help protect against freeze damage by insuring that ice formation is limited to extracellular spaces. Geukensia demissa, a freeze tolerant, salt marsh bivalve mollusc was examined for the presence of ice nucleating proteins. The ice-nucleating temperature (INT) of the hemolymph was not significantly different from artificial seawater of the same salinity indicating the lack of an ice nucleating protein in the hemolymph. The palial fluid did have an elevated INT, indicating the presence of an ice nucleator. The INT of the palial fluid was significantly reduced by boiling and filtration through a 0.45-&mgr;m filter. High INT was also observed in the seawater associated with the bivalves, and was demonstrated in water samples collected from salt marshes but not sand and pebble beaches. Moreover, the INT of water samples collected from a salt marsh decreased in the summer. All of these data suggest that the ice-nucleating agents in the hemolymph and the seawater are ice-nucleating bacteria. One species of ice-nucleating bacteria, Pseudomonas fulva was isolated from the gills of Geukensia. These bacteria could perform the same function as hemolymph ice-nucleating proteins by limiting ice formation to extracellular compartments.

中文翻译：

---

潮间带双壳类软体动物 Geukensia demissa 鳃中冰核细菌的分离鉴定

在秋天，耐冻潮间带无脊椎动物通常会产生分泌到血淋巴中的冰核蛋白。这些蛋白质通过确保冰的形成仅限于细胞外空间来帮助防止冻害。Geukensia demissa，一种耐冻的盐沼双壳软体动物，用于检查冰核蛋白的存在。血淋巴的冰成核温度（INT）与相同盐度的人造海水没有显着差异，表明血淋巴中缺乏冰成核蛋白。苍白液确实具有升高的 INT，表明存在冰核剂。通过煮沸和通过 0.45-&mgr;m 过滤器过滤，苍白液的 INT 显着降低。在与双壳类动物相关的海水中也观察到了高 INT，并在从盐沼收集的水样中得到了证明，但没有在沙子和卵石滩中得到证明。此外，从盐沼收集的水样的 INT 在夏季下降。所有这些数据表明，血淋巴和海水中的冰核剂是冰核细菌。从 Geukensia 的鳃中分离出一种冰核细菌 Pseudomonas fulva。这些细菌可以通过限制细胞外区室的冰形成来执行与血淋巴冰核蛋白相同的功能。从 Geukensia 的鳃中分离出一种冰核细菌 Pseudomonas fulva。这些细菌可以通过限制细胞外区室的冰形成来执行与血淋巴冰核蛋白相同的功能。从 Geukensia 的鳃中分离出一种冰核细菌 Pseudomonas fulva。这些细菌可以通过限制细胞外区室的冰形成来执行与血淋巴冰核蛋白相同的功能。