Tissue and stage-specific juvenile hormone esterase (JHE) and epoxide hydrolase (JHEH) enzyme activities and Jhe transcript abundance in lines of the cricket Gryllus assimilis artificially selected for plasma JHE activity: Implications for JHE microe

摘要

Fat body and midgut juvenile hormone esterase (JHE) and juvenile hormone epoxide hydrolase (JHEH) specific activities, and plasma JHE activity, were measured throughout the last stadium in two pairs (blocks) of lines of the cricket Gryllus assimilis, each pair of-which had been artificially selected for high- or low-plasma JHE activity. Highly significant differences were observed between high- and low-activity lines of each block on most days for fat body JHE, and on one day for midgut JHE activity. In each block, line differences in developmental profiles for fat body JHE activity paralleled line differences in plasma JHE activity during the early-mid stadium, but not during the latter part of the stadium. The developmental profile of midgut JHE activity differed front that of plasma and fat body JHE activity, exhibiting peaks during the early and latter parts of the stadium. Midgut and fat body JHEH activities exhibited a mid-stadium peak in all lines, but activities were very similar in all lines. Fat body JHE appears JHE. During the middle of the last to be a more significant contributor to plasma JHE than is midgut stadium (day 4), Jhe transcript abundance was significantly higher in fat body Or midgut Of high- VS. low-JHE-activity lines. Jhe transcript abundance was positively correlated with JHE enzyme activity in either fat body or midgut and with plasma JHE activity. Natural populations of G. assimilis harbor genetic variation for Jhe gene expression which appears to contribute to genetic variation in JHE specific activity in fat body and midgut. These genes appeal to have been the targets of artificial selection that resulted in lines that differ dramatically in high- or low-plasma JHE activity. These genes appeal to have little, if any, pleiotropic effects on JHEH specific activity. (C) 2008 published by Elsevier Ltd.