Patel M N, Perry R N, Wright D J
Department of Biology, Imperial College of Science, Technology & Medicine, Ascot, Berkshire, U.K.
Int J Parasitol. 1997 Jan;27(1):61-70. doi: 10.1016/s0020-7519(96)00154-3.
The survival of exsheathed infective juveniles (IJs) of 4 Steinernema species, S. glaseri (NC), S. feltiae (UK76), S. carpocapsae (All) and S. riobravis (Biosys355), was assessed following fast and slow drying on glass slides and 1% (w/v) agarose, respectively. Freshly harvested and aged (75-day-old) IJs were desiccated on glass slides after removal of superficial water, at 0, 20, 40, 60 and 80% relative humidity (r.h.). Survival was assessed after rehydration with water, and movement was used as the criterion for survival. Evidence for an intrinsic mechanism to control water loss and survive desiccation was found in freshly harvested S. carpocapsae IJs. At all r.h.s tested, S. carpocapsae had the greatest survival and the slowest rate of water loss. For example, at 80% r.h. the survival time for 50% (S50) of S. carpocapsae IJs was ca. 45 min compared with 5-20 min for the other species. Survival of aged IJs was markedly reduced in the case of S. carpocapsae and S. riobravis, and to a lesser extent in S. feltiae and S. glaseri. The 2nd stage juvenile cuticle (sheath) was not important in aiding desiccation survival of S. carpocapsae and S. glaseri. Drying IJs slowly on 1% agarose at 80% r.h. greatly improved the survival of all 4 species, particularly S. glaseri and S. feltiae. The work is discussed in relation to possible mechanisms for survival of IJs during fast and slow drying.
分别在载玻片和1%（w/v）琼脂糖上进行快速和缓慢干燥后，评估了4种斯氏线虫（Steinernema）即格氏斯氏线虫（S. glaseri，NC）、费氏斯氏线虫（S. feltiae，UK76）、小卷蛾斯氏线虫（S. carpocapsae，All）和里奥布拉沃斯氏线虫（S. riobravis，Biosys355）脱鞘感染性幼虫（IJs）的存活情况。将刚收获的和老化（75日龄）的IJs去除表面水分后，在相对湿度（r.h.）为0、20、40、60和80%的条件下在载玻片上进行干燥处理。用水复水后评估存活率，并以活动能力作为存活的标准。在刚收获的小卷蛾斯氏线虫IJs中发现了一种控制水分流失和在干燥环境中存活的内在机制的证据。在所有测试的相对湿度条件下，小卷蛾斯氏线虫的存活率最高，水分流失速率最慢。例如，在80%相对湿度下，50%（S50）的小卷蛾斯氏线虫IJs的存活时间约为45分钟，而其他物种为5 - 20分钟。在小卷蛾斯氏线虫和里奥布拉沃斯氏线虫中，老化IJs的存活率显著降低，费氏斯氏线虫和格氏斯氏线虫的降低程度较小。第二阶段幼虫的角质层（鞘）对小卷蛾斯氏线虫和格氏斯氏线虫的干燥存活帮助不大。在80%相对湿度下于1%琼脂糖上缓慢干燥IJs大大提高了所有4个物种的存活率，尤其是格氏斯氏线虫和费氏斯氏线虫。本文结合IJs在快速和缓慢干燥过程中的可能存活机制对该研究进行了讨论。
