Submitted to: Comparative Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 28, 2005
Publication Date: August 24, 2005
Citation: Coudron, T.A., Brandt, S.L. 2005. Precocious induction of vitellogenin with JH III in the two-spotted stink bug, Perillus bioculatus (Heteroptera: Pentatomidae). Comparative Biochemistry and Physiology. 142A:79-83. Interpretive Summary: Hormones often occur in low concentrations and during short periods in the life of an organism. Those traits make it challenging to discover and characterize the chemical structure of hormones. It is a common practice to develop an assay that involves treatment of the live organism (bioassay), as a method to study and purify a new hormone. Frequently, those bioassays are complicated processes, thereby discouraging researchers to conduct such studies and resulting in delays in the characterization of the hormones. This paper describes a bioassay employing an electrophoretic detection method that can be used to characterize reproductive hormones in the group of insects known as the true bugs, which have been especially difficult to work with when studying hormones. The new bioassay has been designed to be clear in interpretation, easy and rapid to conduct, and to be doable by most all researchers. It is expected that this technique will be a welcomed discovery for a large group of researchers that have been conducting hormone studies with heteropteran species, and that the use of this technique will result in the characterization of their reproductive hormones.
Technical Abstract: Vitellogenesis was examined in Perillus bioculatus as a means to develop a bioassay for detecting substances with juvenile hormone (JH) activity. While the chemical identity of several JHs has been determined, isolation and characterization of JHs in Heteroptera has not been accomplished, although evidence suggests that it is different from the JH of other insect orders. Several bioassay systems have been developed to detect the presence of JHs or compounds with JH activity. Most of these bioassays are laborious and require several days to complete. We have developed a new bioassay system to detect compounds with JH activity in Perillus bioculatus. Adult females were treated topically with JH III, and the premature presence of vitellogenin in the hemolymph was then detected using electrophoresis and Western blot analyses. JH III treatment resulted in an early production of vitellogenin that was detectable 48 h before vitellogenin was present in non-treated insects. These results suggest that this bioassay may be useful in the isolation of JHs and detection and purification of chemicals with JH activity in Perillus bioculatus as well as in other species of Hereroptera. This technique is more rapid than previous methods and does not require rearing an additional insect species.