Liu Feng, Xia Xiaoming, Liu Nannan
Department of Entomology and Plant Pathology, Auburn UniversityAuburn, AL, United States.
Front Physiol. 2017 Jun 20;8:418. doi: 10.3389/fphys.2017.00418. eCollection 2017.
As the most extensively used chemical repellent, N,N-diethyl-3-methylbenzamide (DEET) displayed repellency to a wide range of insects, including the common bed bug, . While the neuronal or molecular basis involved in DEET's repellency have been majorly focused on mosquitos and fruit flies, DEET's repellency to the common bed bug is largely unreached. To gain new insights into the cellular and molecular mechanisms in DEET's repellency to the common bed bug, we characterized the neuronal response of bed bugs to DEET, identified the olfactory receptors targeted by DEET and demonstrated the interfering effect of DEET on bed bug's responses to human odorants. High doses of DEET were required for activating the olfactory receptor neurons in the sensilla of bed bugs and at least three DEET-sensitive receptors were functionally deciphered. These DEET-sensitive receptors presented even more sensitive to certain botanical terpenes/terpenoids which also displayed repellency at varying levels for bed bugs. In addition, DEET produced a blocking effect on the neuronal responses of bed bugs to specific human odors and showed inhibitory effect on the function of odorant receptors in responding to certain human odors. Taken together, our results indicate that DEET may function as a stimulus that triggers avoidance behaviors and a molecular "confusant" for interrupting the host odor recognition in the odorant receptors of bed bugs. The receptors that coincidently responded to both synthetic DEET and botanical terpenes/terpenoids suggested that DEET probably target on receptors that originally responded to terpenes/terpenoids. This study gave novel insight into the mechanisms of DEET's repellency to bed bugs and also provided valuable information for developing new reagents for bed bug control.
作为使用最广泛的化学驱避剂，N,N-二乙基-3-甲基苯甲酰胺（避蚊胺）对包括普通臭虫在内的多种昆虫都有驱避作用。虽然避蚊胺驱避作用的神经或分子基础主要集中在蚊子和果蝇上，但避蚊胺对普通臭虫的驱避作用在很大程度上尚未得到研究。为了深入了解避蚊胺对普通臭虫驱避作用的细胞和分子机制，我们对臭虫对避蚊胺的神经反应进行了表征，确定了避蚊胺靶向的嗅觉受体，并证明了避蚊胺对臭虫对人类气味反应的干扰作用。激活臭虫感器中的嗅觉受体神经元需要高剂量的避蚊胺，并且至少有三种对避蚊胺敏感的受体在功能上得到了解析。这些对避蚊胺敏感的受体对某些植物萜类/萜烯类化合物表现出更高的敏感性，这些化合物对臭虫也有不同程度的驱避作用。此外，避蚊胺对臭虫对特定人类气味的神经反应产生了阻断作用，并对气味受体在响应某些人类气味时的功能表现出抑制作用。综上所述，我们的结果表明，避蚊胺可能作为一种触发回避行为的刺激物，以及一种分子“混淆剂”，用于中断臭虫气味受体中的宿主气味识别。同时对合成避蚊胺和植物萜类/萜烯类化合物有反应的受体表明，避蚊胺可能靶向最初对萜类/萜烯类化合物有反应的受体。这项研究为避蚊胺对臭虫的驱避机制提供了新的见解，也为开发新的臭虫控制试剂提供了有价值的信息。
