Bekelaar Kiliana, Waghorn Tania, Tavendale Michael, McKenzie Catherine, Leathwick Dave
AgResearch Ltd, Grasslands Research Centre, Private Bag, Palmerston North, 11008, New Zealand.
Parasitol Res. 2019 Feb;118(2):707-710. doi: 10.1007/s00436-018-6183-1. Epub 2019 Jan 4.
A crucial step in the infection process of grazing ruminants by gastro-intestinal nematodes is the exsheathment of the infective third-stage larva following ingestion. Recently, heat shock was shown to play an important role in the carbon dioxide (CO)-dependent exsheathment response in Haemonchus contortus. The current in vitro study set out to evaluate the role of heat shock in other abomasal species. In rumen fluid, all species tested exsheathed rapidly and efficiently in response to heat shock and CO This response was significantly higher compared to slow temperature changes, supporting the hypothesis that heat shock plays an important role in vivo. However, in artificial buffer, the effect of heat shock was species-dependent. For H. contortus and Ostertagia leptospicularis, the response in artificial buffer was similar to rumen fluid. In contrast, Ostertagia ostertagi and Teladorsagia circumcincta exsheathment was significantly lower and/or slower in artificial buffer, and there was no benefit of heat shock. For these two species, it appears that there are co-factors in the rumen fluid, in addition to heat shock and CO, contributing to exsheathment. Overall, the data indicate that there are significant differences between abomasal species in their response to exsheathment triggers.
胃肠道线虫感染放牧反刍动物过程中的一个关键步骤是，感染性第三期幼虫在被摄入后脱去鞘膜。最近的研究表明，热休克在捻转血矛线虫依赖二氧化碳（CO）的脱鞘反应中起重要作用。当前的体外研究旨在评估热休克在其他皱胃线虫物种中的作用。在瘤胃液中，所有受试物种对热休克和CO的反应都能快速且高效地脱鞘。与缓慢的温度变化相比，这种反应明显更高，这支持了热休克在体内起重要作用的假设。然而，在人工缓冲液中，热休克的效果因物种而异。对于捻转血矛线虫和细颈奥斯特线虫，在人工缓冲液中的反应与瘤胃液相似。相比之下，在人工缓冲液中，奥氏奥斯特线虫和环形泰勒虫的脱鞘明显更低和/或更慢，热休克没有益处。对于这两个物种，除了热休克和CO外，瘤胃液中似乎还有其他辅助因子有助于脱鞘。总体而言，数据表明，皱胃线虫物种对脱鞘触发因素的反应存在显著差异。
