Identification and characterization of ice nucleators transmitting from prey to predator

作为鉴定家蛛（Achaearanea tepidaroirum）外源冰核因子的第一步，研究了冰核因子在猎物（Porcellio scaber）体内的位置及其热敏感性。吞食等足类动物的肠道使蜘蛛的过冷却点从-5 ℃提高到-9 ℃，这种效果与猎物的整个身体相当。这意味着冰成核剂至少存在于猎物的消化道中，从而表明猎物在进食过程中将它们纳入其中。以加热的等足类动物肠道为食的蜘蛛比以不加热的肠道为食的蜘蛛具有更低的过冷却点。因此，从猎物到捕食者的冰成核剂传输容易受到热，从而表明它是有机的起源。为了表征冰成核剂，他们的季节和地理丰富的领域进行了检查。我发现，冰核全年都有发生，从日本北方到南部的地理范围很广。几乎所有野外采集的猎物，如蟋蟀、蚂蚁和等足类动物都含有它们。这些观测结果表明，冰核因子从猎物到捕食者的传递在野外是很常见的。细菌等冰核活性微生物因其广泛存在而成为冰核剂的候选者。

As the first step to identify the exgenous ice nucleators of the house spider, Achaearanea tepidaroirum, location of ice nucleators in the body of prey animals (Porcellio scaber) and its heat susceptibility were examined. Ingestion of the isopod's gut elevated the spider's supercooling point from -5 to -9C and this effect was comparable to that of whole body of the prey. This means that the ice nucleators exist at least in the alimentary canal of the prey animals, thus suggesting that the prey animals incorporate them in the process of feeding. Spiders that fed on a heated isopod's gut had a lower supercooling point than those fed on an unheated gut. Thus, the ice nucleators transmitting from prey to predator were susceptible to heat, thus suggesting that it is organic in origin.To characterize the ice nucleators, their seasonal and geographical abundance in the field was examined. I found that the ice nucleators occur whole the year round and wide geographical range from northern to southern Japan. Almost all field-collected prey animals such as cricket, ants and isopods contain them. These observatons strongly suggest that the ice nucleators transmitting from prey to predator are common in the field. Because of the ubiquity, ice nucleating active microorganism such as bacteria can be the candicates as the ice nucleator.