Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.
J Comp Physiol B. 2011 Jul;181(5):631-40. doi: 10.1007/s00360-011-0552-8. Epub 2011 Jan 30.
The presence of large-molecular-mass, thermal hysteresis (TH)-producing antifreezes (e.g., antifreeze proteins) has been reported in numerous and diverse taxa, including representative species of fish, arthropods, plants, fungi, and bacteria. However, relatively few of these antifreeze molecules have been chemically characterized. We screened diverse species by subjecting their homogenates to ice-affinity purification and discovered the presence of a newly identified class of antifreeze, a xylomannan-based TH-producing glycolipid that was previously reported in one species of freeze-tolerant Alaskan beetle. We isolated xylomannan-based antifreeze glycolipids from one plant species, six insect species, and the first frog species to be shown to produce a large-molecular-mass antifreeze. (1)H NMR spectra of the ice-purified molecules isolated from these diverse freeze-tolerant and freeze-avoiding organisms were nearly identical, indicating that the chemical structures of the glycolipids were highly similar. Although the exact functions remain uncertain, it appears that antifreeze glycolipids play a role in cold tolerance.
已在包括鱼类、节肢动物、植物、真菌和细菌等多种生物的代表物种中发现了具有大分子量、热滞（TH）特性的防冻剂（例如，防冻蛋白）的存在。然而，这些防冻分子中只有相对较少的分子得到了化学表征。我们通过对其匀浆进行冰亲和力纯化来筛选了多种物种，并发现了一种新鉴定的防冻剂类，即基于木聚糖的 TH 产生糖脂，先前在一种耐冻的阿拉斯加甲虫中报道过。我们从一个植物物种、六个昆虫物种以及第一个被证明产生大分子量防冻剂的青蛙物种中分离出基于木聚糖的防冻糖脂。从这些耐冻和避冻生物中分离出的冰纯化分子的（1）H NMR 谱几乎完全相同，表明糖脂的化学结构非常相似。尽管确切的功能仍不确定，但防冻糖脂似乎在耐寒性中发挥作用。
