Department of Biological Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada.
Int J Mol Sci. 2022 Sep 29;23(19):11505. doi: 10.3390/ijms231911505.
Common bed bugs, , can carry, but do not transmit, pathogens to the vertebrate hosts on which they feed. Some components of the innate immune system of bed bugs, such as antimicrobial peptides (AMPs), eliminate the pathogens. Here, we determined the molecular characteristics, structural properties, and phylogenetic relatedness of two new defensins (CL-defensin1 (XP_024085718.1), CL-defensin2 (XP_014240919.1)), and two new defensin isoforms (CL-defensin3a (XP_014240918.1), CL-defensin3b (XP_024083729.1)). The complete amino acid sequences of CL-defensin1, CL-defensin2, CL-defensin3a, and CL-defensin3b are strongly conserved, with only minor differences in their signal and pro-peptide regions. We used a combination of comparative transcriptomics and real-time quantitative PCR to evaluate the expression of these defensins in the midguts and the rest of the body of insects that had been injected with bacteria or had ingested blood containing the Gram-positive (Gr+) bacterium and the Gram-negative (Gr-) bacterium . We demonstrate, for the first time, sex-specific and immunization mode-specific upregulation of bed bug defensins in response to injection or ingestion of Gr+ or Gr- bacteria. Understanding the components, such as these defensins, of the bed bugs' innate immune systems in response to pathogens may help unravel why bed bugs do not transmit pathogens to vertebrates.
常见的臭虫 可以携带，但不会传播，病原体到脊椎动物宿主的，它们饲料。一些组件的固有免疫系统的臭虫，如抗菌肽（AMP），消除病原体。在这里，我们确定的分子特征，结构特性，和系统发育的关系，两个新的防御素（CL-防御素 1 （XP_024085718.1），CL-防御素 2 （XP_014240919.1）），和两个新的防御素同工型（CL-防御素 3a （XP_014240918.1），CL-防御素 3b （XP_024083729.1））。完整的氨基酸序列的 CL-防御素 1，CL-防御素 2，CL-防御素 3a，和 CL-防御素 3b 是强烈的保守，只有在他们的信号和前肽区的微小差异。我们使用了组合的比较转录组学和实时定量 PCR 来评估这些防御素的表达在中肠和身体的其余部分的昆虫已被注射细菌或已摄入血液中含有革兰氏阳性（Gr +）细菌和革兰氏阴性（Gr-）细菌 。我们证明，首次，性别特异性和免疫模式特异性上调的臭虫防御素反应注射或摄入 Gr +或 Gr-细菌。了解组件，如这些防御素，固有免疫系统的臭虫对病原体可能有助于揭示为什么臭虫不传播病原体到脊椎动物。
