Larsen M, Wolstrup J, Henriksen S A, Dackman C, Grønvold J, Nansen P
Department of Veterinary Microbiology, Royal Veterinary and Agricultural University, Bülowsvej, Frederiksberg, Denmark.
J Helminthol. 1991 Sep;65(3):193-200. doi: 10.1017/s0022149x00010701.
Laboratory experiments were designed to select nematophagous fungi that were able to survive in vitro conditions simulating passage through the gastro-intestinal tract of cattle. All of the tests were conducted at 39 degrees C. In a primary stress selection step in diluted rumen fluid, 21 isolates were obtained. Each of the primary stress selected isolates was tested in synthetic saliva, rumen fluid simulating the activity in the rumen, rumen fluid followed by pepsin-hydrochloric acid treatment simulating the additional effect of ruminal and abomasal activity, pepsin-hydrochloric acid solution simulating conditions in the abomasum and finally in a trypsin solution as an example of enzyme activity in the gut. The effect of the rumen fluid alone, or rumen fluid followed by pepsin-hydrochloric acid treatment, were responsible for the reduction in surviving fungal isolates. Only six of thirteen isolates belonging to the genus Arthrobotrys survived while seven of eight isolates of the genus Duddingtonia survived. Fourteen isolates were tested for their predatory capacity in a dung pat bioassay. Fungi of the genera Arthrobotrys and Duddingtonia reduced the development of Ostertagia ostertagi third stage larvae by approximately 75% and 96% respectively compared to the number of larvae that developed from fungus-free control pats.
实验室实验旨在筛选能够在模拟牛胃肠道通过情况的体外条件下存活的食线虫真菌。所有测试均在39摄氏度下进行。在稀释瘤胃液中的初级应激选择步骤中，获得了21个分离株。对每个经初级应激选择的分离株在合成唾液、模拟瘤胃活动的瘤胃液、经胃蛋白酶 - 盐酸处理以模拟瘤胃和皱胃活动附加效应的瘤胃液、模拟皱胃条件的胃蛋白酶 - 盐酸溶液中进行测试，最后在胰蛋白酶溶液中进行测试，以此作为肠道酶活性的示例。单独的瘤胃液或经胃蛋白酶 - 盐酸处理的瘤胃液导致存活真菌分离株数量减少。属于节丛孢属的13个分离株中只有6个存活，而达丁顿属的8个分离株中有7个存活。在粪便块生物测定中测试了14个分离株的捕食能力。与无真菌对照粪便块中发育的幼虫数量相比，节丛孢属和达丁顿属真菌分别使奥斯特他线虫第三期幼虫的发育减少了约75%和96%。
