Raymond James A, Knight Charles A
Department of Biological Sciences, University of Nevada, 4505 Maryland Pkwy S., Las Vegas, NV 89154, USA.
Cryobiology. 2003 Apr;46(2):174-81. doi: 10.1016/s0011-2240(03)00023-3.
Extracellular macromolecules associated with Antarctic sea ice diatoms were previously shown to have ice-binding activities. The function of these ice-active substances (IASs) has not been identified. Here we show that two of the IASs have a strong ability to inhibit the recrystallization of ice, possibly signifying a cryoprotectant function. To test this possibility, two species of marine diatom (one Antarctic and one temperate) were subjected to a single freeze-thaw cycle (approximately 20h at -4 or -5 degrees C) in the presence or absence of IAS. Viability, based on a double staining technique, was 15-29% higher in the presence of IAS. Etching of single crystal ice hemispheres grown from dilute IAS solutions indicated that the IASs bind to specific faces of ice and are incorporated into the ice lattice. Together, these results suggest that the IASs acts as a cryoprotectant, probably through some ice-binding mechanism.
先前的研究表明，与南极海冰硅藻相关的细胞外大分子具有冰结合活性。这些冰活性物质（IASs）的功能尚未确定。在此我们表明，其中两种IASs具有很强的抑制冰重结晶的能力，这可能意味着它们具有抗冻保护功能。为了验证这一可能性，在有或没有IASs的情况下，将两种海洋硅藻（一种来自南极，一种来自温带）进行单次冻融循环（在-4或-5摄氏度下约20小时）。基于双重染色技术的活力测定表明，在有IASs的情况下，活力要高出15%-29%。从稀IASs溶液中生长的单晶冰半球的蚀刻表明，IASs与冰的特定面结合并融入冰晶格。这些结果共同表明，IASs可能通过某种冰结合机制起到抗冻保护剂的作用。
