Unidad de Investigación en Helmintología, Centro Nacional de Investigación Disciplinaria en Salud Animal e Inocuidad, Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias, Boulevar Paseo Cuauhnahuac No. 8534, Col. Progreso, 62550, Jiutepec, Morelos, Mexico.
Unidad de Biotecnología, Centro de Investigación Científica de Yucatán A.C., Calle 43 No. 130 x 32 y 34, Chuburná de Hidalgo, 97205, Mérida, Yucatán, Mexico.
Acta Parasitol. 2022 Jun;67(2):678-686. doi: 10.1007/s11686-021-00502-4. Epub 2022 Jan 11.
This study was designed to investigate if culturing nematophagous fungi (NF) in the presence of a Haemonchus contortus larva crude extract (HcCE) enhances the nematocidal activity of nematophagous fungi liquid culture filtrates (NFCF).
Four NF Arthrobotrys oligospora, A. musiformis, Duddingtonia flagrans and Clonostachys rosea were cultured in flasks (n = 5) containing Czapek-Dox broth medium (CDB) in the presence or absence of HcCE. NFCF recovered by filtration of each fungus (200 mg/mL) were assessed on H. contortus infective larvae (L3) using 96-well micro-titer plates (n = 4). Additionally, CDB and water were considered negative controls, while Ivermectin acted as a positive control. After 48 h confrontation, ten 10-μL aliquots of each well were deposited on slides and observed under the microscope (40 ×). Dead and alive larvae in the aliquots were quantified, and a mortality rate (MR) was estimated.
The MR of the different NFCF was greatly enhanced by the presence of HcCE. The four NF incubated in the absence of HcCE showed low mortality percentages from 8.2 to 25.8%; in contrast, when the assessed NF growth in the presence of HcCE showed a lethal activity ranging from 66.8 to 80.5%. Only C. rosea showed a moderate increase in the presence of the elicitor (42.7%).
This study shows evidence about the HcCE enhances the production of nematocidal activity in NFCF. Future studies should be performed to elucidate the compounds responsible of the nematocidal activity that could have important implications in the control of sheep haemonchosis.
本研究旨在探讨在旋毛虫幼虫粗提物（HcCE）存在的情况下培养食线虫真菌（NF）是否能增强食线虫真菌液体培养滤液（NFCF）的杀线虫活性。
将 4 种 NF （寡孢节丛孢菌、弯孢节丛孢菌、厚垣轮枝孢和淡紫拟青霉）分别在含有察氏培养基（CDB）的培养瓶中（n=5）进行培养，分别在有/无 HcCE 的情况下培养。通过 96 孔微量滴定板（n=4）评估每种真菌（200 mg/mL）过滤后获得的 NFCF 对感染性幼虫（L3）的影响。此外，CDB 和水被认为是阴性对照，伊维菌素作为阳性对照。48 小时后，将每个孔的 10 个 10 μL 等分试样滴在载玻片上，在显微镜下（40×）观察。对等分试样中的死幼虫和活幼虫进行定量，并估计死亡率（MR）。
HcCE 的存在大大增强了不同 NFCF 的 MR。在没有 HcCE 的情况下培养的 4 种 NF 显示出较低的死亡率，从 8.2%到 25.8%；相比之下，当评估的 NF 在 HcCE 存在下生长时，其致死活性范围从 66.8%到 80.5%。只有玫瑰拟青霉在存在诱导剂的情况下显示出适度的增加（42.7%）。
本研究表明，HcCE 增强了 NFCF 产生的杀线虫活性。未来的研究应该阐明负责杀线虫活性的化合物，这可能对控制绵羊血矛线虫病具有重要意义。
