0022-1910(94)00084-0 J. Insect Physiol. Vol. 41, No. 2, pp. 179-189, 1995 Elsevier Science Ltd. Printed in Great Britain Metabolism of the Juvenile Hormone in zyxwvutsrqponmlkji Drosophila Adults under Normal Conditions and Heat Stress: Genetical and Biochemical Aspects I. Y. RAUSCHENBACH,*t T. M. KHLEBODAROVA,* N. A. CHENTSOVA,* N. E. GRUNTENKO,* L. G. GRENBACK,* E. I. YANTSEN,$ M. L. FILIPENKOS Received IO February 1994; revised 12 July 1994 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA By means of ion exchange chromatography two forms of JH-esterase were identified in D. virilis. One was sensitive to diisopropylphosphofluridate (DFP) and one was DFP-insensitive. It was found that both forms are inhibited by 3-octylthio-1,1-1-trifluoropropan-2-one. By means of immunoblotting analysis with the use of antiserum produced against pupal DFP-insensitive JH-esterase, it was shown that this form is present in adults and that it lacks the capacity to hydrolyze naphthyl acetate at a significant rate. The metabolism of the juvenile hormone (JH) was studied in adults of two Drosophifa species (D. virilis and D. melunogaster) under normal thermal conditions and short-term heat stress. It was demonstrated that females of both species respond to stress by a decrease in the activity of JH-esterase. This decrease is effected through a decrease in protein. JH metabolism in males of both species does not change under heat stress. A genetic analysis of the differences in the activity of DFP-insensitive JH-esterase between lines of D. virilis sensitive and resistant to stress was carried out. It was demonstrated that the given differences are under the control of a single autosomal gene. Juvenile hormone Drosophila Heat stress INTRODUCTION It is known that the juvenile hormone (JH) plays a very important role in development and function of insects: it controls metamorphosis (see reviews, Hammock, 1985; Riddiford, 1985); it regulates the maturation of the reproductive functions (Koeppe et al., 1985; Shapiro et al., 1986); it is involved in the control of diapause (Delinger and Tanaka, 1989) and the determination of castes (Rachinsky and Hartfelder, 1990). It has been demonstrated that some insects respond to stress by either delay (or block) of metamorphosis or by passage into a state of diapause and that these two events are under hormonal control (see review, Rauschenbach, 1991). The response of the JH metabolic system to stress has been studied. It has been shown, in some cases, that the content of JH increases, and the activity of JH- *Institute of Cytology and Genetics, Siberian Department, Russian Academy of Sciences, Novosibirsk 630090, Russia. tTo whom correspondence should be addressed. IInstitute of Bioorganic Chemistry, Siberian Department, Russian Academy Sciences, Novosibirsk 630090, Russia. esterase, an enzyme degrading JH, decreases in develop- ing insects exposed to long-term stress (see reviews, Cymborovski, 1991; Rauschenbach, 1991). The gene system controlling these events in Drosophila virilis has been identified, and the mechanism providing its func- tion has been studied in detail (Rauschenbach, 1988, 1991). However, very little is known about the state of the JH metabolic system under stress and virtually nothing is known about its genetic control in adult insects. An advantageous model for providing data filling these gaps of our knowledge involves the use of two lines of Drosophila virilis we previously established. The two lines differ in the response of larvae and pupae to heat stress. In individuals of line 101 developing under con- ditions of heat stress (32”(Z), there develops a hormonal response to stress providing adaptation to unfavorable conditions and the normal course of metamorphosis. In individuals of the other line (147), a temperature- sensitive mutation disturbs one of the links of the stress response (under stressful conditions the activity of JH- esterase does not decrease), and they are incapable of 179