Nasr Nadia M, Fallon Ann M
Department of Entomology, University of Minnesota, 1980 Folwell Avenue, St. Paul, MN 55108, USA.
J Invertebr Pathol. 2003 Mar;82(3):162-6. doi: 10.1016/s0022-2011(03)00030-2.
Using molecular approaches, we have recently shown that the C7-10 mosquito cell line from Aedes albopictus, and the Aag-2 line from Aedes aegypti, secrete a variety of immune peptides into the culture medium, including cecropins, defensins, transferrin, and lysozyme. The diversity of these peptides makes it difficult to quantify the relative activities of each molecule, because possible synergistic interactions may occur. Using a microtiter plate assay with live bacteria, we now show that C7-10 cells secrete an activity that is more potent against the Gram-positive bacterium, Micrococcus luteus, than against Gram-negative Escherichia coli. This lysozyme-like activity is accompanied by production of a lytic zone in an agarose plate assay containing commercially available, lyophilized M. luteus. Properties of the lysozyme-like activity from C7-10 cells included a broad pH optimum from 5.5 to 6.5, and heat-sensitivity above 42 degrees C. Amounts of secreted activity increased during the initial 24h of incubation with heat-killed bacteria. During this induction, lysozyme-like activity was found primarily in the cell culture supernatant.
利用分子生物学方法，我们最近发现，白纹伊蚊的C7 - 10蚊细胞系和埃及伊蚊的Aag - 2细胞系会向培养基中分泌多种免疫肽，包括天蚕素、防御素、转铁蛋白和溶菌酶。这些肽的多样性使得难以量化每个分子的相对活性，因为可能会发生协同相互作用。通过使用含有活细菌的微量滴定板测定法，我们现在发现C7 - 10细胞分泌的一种活性物质对革兰氏阳性菌藤黄微球菌的作用比对革兰氏阴性菌大肠杆菌更强。这种类似溶菌酶的活性在含有市售冻干藤黄微球菌的琼脂平板测定中伴随着溶菌区的产生。C7 - 10细胞中类似溶菌酶活性的特性包括5.5至6.5的宽pH最佳值以及42摄氏度以上的热敏感性。在与热灭活细菌孵育的最初24小时内，分泌活性的量增加。在此诱导过程中，类似溶菌酶的活性主要存在于细胞培养上清液中。
