Bartholomay L C, Fuchs J F, Cheng L-L, Beck E T, Vizioli J, Lowenberger C, Christensen B M
Department of Animal Health and Biomedical Sciences, University of Wisconsin, Madison, WI 53706, USA.
Insect Mol Biol. 2004 Apr;13(2):125-32. doi: 10.1111/j.0962-1075.2004.00467.x.
Defensin is the predominant inducible immune peptide in Aedes aegypti. In spite of its activity against Gram-positive bacteria in vitro, defensin expression is detected in mosquitoes inoculated with Gram-positive or negative bacteria, or with filarial worms. Defensin transcription and expression are dependent upon bacterial dose; however, translation is inconsistent with transcription because peptide is detectable only in mosquitoes inoculated with large doses. In vitro translation assays provide further evidence for post-transcriptional regulation of defensin. Clearance assays show that a majority of bacteria are cleared before defensin is detected. In gene silencing experiments, no significant difference in mortality was observed between defensin-deficient and control mosquitoes after bacteria inoculation. These studies suggest that defensin may have an alternative function in mosquito immunity.
防御素是埃及伊蚊中主要的可诱导免疫肽。尽管其在体外对革兰氏阳性菌有活性，但在接种革兰氏阳性或阴性细菌或丝虫的蚊子中都能检测到防御素表达。防御素转录和表达取决于细菌剂量；然而，翻译与转录不一致，因为只有在接种大剂量细菌的蚊子中才能检测到肽。体外翻译试验为防御素的转录后调控提供了进一步证据。清除试验表明，在检测到防御素之前，大多数细菌已被清除。在基因沉默实验中，接种细菌后，防御素缺陷型蚊子和对照蚊子之间未观察到死亡率有显著差异。这些研究表明，防御素在蚊子免疫中可能具有其他功能。
