Mihok S, Stiles J K, Mpanga E, Olubayo R O
International Centre of Insect Physiology and Ecology, Nairobi, Kenya.
Med Vet Entomol. 1994 Jan;8(1):47-50. doi: 10.1111/j.1365-2915.1994.tb00383.x.
Midgut protease activity in Glossina morsitans centralis and G.m. morsitans, at 48 h post bloodmeal averaged 1.8IU of trypsin-like activity. These two tsetse subspecies differ in their susceptibility to trypanosome infection. Except for low levels in flies fed on waterbuck blood (0.7 IU), activity did not differ in flies fed a variety of host bloods (goat, pig, cow, buffalo, eland) and trypanosome species (Trypanosoma congolense, T. brucei, T. simiae). Protease activity was also not correlated with infection rates, despite large differences in infection rates among experiments. Nevertheless, addition of 0.06 M D(+)-glucosamine to parasitaemic blood resulted in a three-fold reduction in protease activity, coincident with a large increase in infection rate. This effect did not occur when parasites or D(+)-glucosamine were added alone to the bloodmeal, suggesting that the effect was due to metabolism of D(+)-glucosamine by parasites.
在采采蝇吸食血餐48小时后，莫氏舌蝇指名亚种（Glossina morsitans centralis）和莫氏舌蝇（G.m. morsitans）的中肠蛋白酶活性平均为1.8国际单位的类胰蛋白酶活性。这两个采采蝇亚种对锥虫感染的易感性不同。除了以水羚血为食的苍蝇中蛋白酶活性较低（0.7国际单位）外，以各种宿主血液（山羊、猪、牛、水牛、大羚羊）和锥虫种类（刚果锥虫、布氏锥虫、西氏锥虫）为食的苍蝇中，蛋白酶活性没有差异。尽管不同实验中的感染率差异很大，但蛋白酶活性也与感染率无关。然而，向含有寄生虫血症的血液中添加0.06 M D(+)-葡萄糖胺会导致蛋白酶活性降低三倍，同时感染率大幅增加。当单独向血餐中添加寄生虫或D(+)-葡萄糖胺时，这种效果不会出现，这表明这种效果是由于寄生虫对D(+)-葡萄糖胺的代谢所致。
