首页 | 本学科首页   官方微博 | 高级检索  
   检索      


Causal connection between detoxification enzyme activity and consumption of a toxic plant compound
Authors:M J Snyder  J I Glendinning
Institution:(1) Department of Entomology, University of Arizona, 85721 Tucson, AZ, USA;(2) ARL Division of Neurobiology, and Center for Insect Science, University of Arizona, 85721 Tucson, AZ, USA;(3) Present address: Bodega Marine Laboratory, P.O. Box 247, 94923 Bodega Bay, CA, USA
Abstract:Insect herbivores can increase their detoxification activities against a particular plant poison in response to prolonged ingestion of the same compound. For example, larval tobacco hornworms (Manduca sexta) experience a dramatic increase in cytochrome P450 activity against nicotine after ingesting nicotine. While it is generally assumed that this induction process permits increased consumption of toxic plant tissues, we are not aware of any direct experimental support for this assumption. Using a two-tiered approach, we examined the functional significance of P450 induction to M. sexta larvae ingesting a toxic but non-deterrent concentration of nicotine. First, we related the time-course of P450 induction in midgut microsomes to changes in nicotine consumption. When offered a nicotine diet, larvae failed to show a significant increase in consumption before 36 h, which was coincident with the time-course of the induction of midgut P450 activities against aldrin and nicotine. Second, we determined whether inhibiting the induced P450 activities affected nicotine consumption. We found that the increase in nicotine consumption following the induction of nicotine metabolism could be strongly inhibited by treatment with piperonyl butoxide, which by itself did not inhibit consumption. These results provide direct evidence for a causal connection between P450-mediated detoxification activity and consumption of a toxic plant compound.Abbreviation PB piperonyl butoxide
Keywords:Insect feeding  P450 enzyme induction  Nicotine  Detoxification enzymes  Allelochemicals
本文献已被 SpringerLink 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号