Nabavi Zohreh, Baniardalani Mozhgan, Basseri Hamidreza
Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
J Arthropod Borne Dis. 2020 Jun 30;14(2):144-152. doi: 10.18502/jad.v14i2.3732. eCollection 2020 Jun.
Lectin molecules have crucial biological role in insects' immune system. The aim of present study was to find the agglutinin activities in haemolymph of German cockroach, with appropriate screening and purification.
The heamolymph of cockroach was collected and agglutinin test performed against different animal and human red blood cells (RBC). Then sugar inhibition assay was carried out to find carbohydrate specific binding lectin. The proteins of haemolymph was purified using ion-exchange chromatography (HPLC) and each fraction was tested for agglutinin activity. Finally the molecular weight of the agglutinin protein was determined using SDS-page.
The most agglutinin activity of haemolymph was found against RBC of mouse at titer 1/128ml/L dilution and sugar inhibition assay showed that fucos, N-acetyglucoseamine and galactose reduced titer of agglutinin to ½ml/L. Only one fraction of heamolymph at rotation time of 36 minute showed agglutinin activity. The molecular weight of this lectin was measured as 120Kds.
The range of agglutinin activities against different RBC indicates that the isolated lectin is not specific for a particular carbohydrate. In addition, the isolated lectin at low concentration present in heamolymph should be an innate lactin not secreted, because we found it without any trigger immunity of the insect.
凝集素分子在昆虫免疫系统中具有关键的生物学作用。本研究的目的是通过适当的筛选和纯化，在德国小蠊的血淋巴中发现凝集素活性。
收集蟑螂的血淋巴，并对不同动物和人类的红细胞（RBC）进行凝集素测试。然后进行糖抑制试验以找到碳水化合物特异性结合凝集素。使用离子交换色谱法（HPLC）纯化血淋巴中的蛋白质，并对每个馏分进行凝集素活性测试。最后，使用SDS-聚丙烯酰胺凝胶电泳测定凝集素蛋白的分子量。
在1/128ml/L稀释度下，血淋巴对小鼠红细胞的凝集素活性最高，糖抑制试验表明，岩藻糖、N-乙酰葡糖胺和半乳糖可将凝集素滴度降低至1/2ml/L。在36分钟的旋转时间下，血淋巴只有一个馏分显示出凝集素活性。该凝集素的分子量测定为120千道尔顿。
针对不同红细胞的凝集素活性范围表明，分离出的凝集素对特定碳水化合物不具有特异性。此外，血淋巴中存在的低浓度分离凝集素应该是一种未分泌的先天性凝集素，因为我们发现它时昆虫没有任何触发免疫反应。
