Kazimírová M, Sulanová M, Trimnellt A R, Kozánek M, Vidlicka L, Labuda M, Nuttall P A
Institute of Zoology, Slovak Academy of Sciences, Bratislava.
Med Vet Entomol. 2002 Sep;16(3):301-9. doi: 10.1046/j.1365-2915.2002.00379.x.
Tabanid flies are telmophages (pool feeders), taking frequent and rapid bloodmeals from many different individual hosts. To investigate how they accomplish this intermittent feeding strategy, we examined the anticoagulant activities in salivary gland extracts (SGE) from 19 species representing six genera: Atylotus, Chrysops, Haematopota, Heptatoma, Hybomitra and Tabanus (Diptera: Tabanidae). Standard coagulation screen assays were used to determine thrombin time, prothrombin time and activated partial thromboplastin time. Chromogenic substrate assays were performed for thrombin and factor Xa activity. SGE of most species (except Chrysops spp.) considerably prolonged human plasma clotting time in a dose-dependent manner, and showed potent and specific antithrombin activity in the chromogenic substrate assay. Heptatoma pellucens displayed the strongest anticoagulant activity. Specific anti-factor Xa activity in tabanid SGE was not detected. Electrophoretic profiles of SGE proteins differed between genera and species. Overall, the results suggest that tabanids have evolved at least two antihaemostatic strategies.
虻类苍蝇是舔吸式口器（池式取食者），频繁且迅速地从许多不同的个体宿主身上吸食血液。为了研究它们如何实现这种间歇性取食策略，我们检测了代表六个属的19个物种唾液腺提取物（SGE）中的抗凝活性，这六个属分别是：麻虻属、斑虻属、角虻属、瘤虻属、黄虻属和虻属（双翅目：虻科）。使用标准凝血筛查试验来测定凝血酶时间、凝血酶原时间和活化部分凝血活酶时间。进行发色底物试验以检测凝血酶和因子Xa活性。大多数物种（除斑虻属物种外）的SGE以剂量依赖的方式显著延长了人血浆凝血时间，并在发色底物试验中显示出强大且特异性的抗凝血酶活性。透明瘤虻表现出最强的抗凝活性。未检测到虻类SGE中的特异性抗因子Xa活性。不同属和物种的SGE蛋白质电泳图谱有所不同。总体而言，结果表明虻类已经进化出至少两种止血策略。
