Insect Biochemistry and Molecular Biology 30 2000 775–783 www.elsevier.comlocateibmb
Stress-reactivity and juvenile hormone degradation in Drosophila melanogaster
strains having stress-related mutations
N.E. Gruntenko
a,
, T.G. Wilson
b
, M. Monastirioti
c
, I.Y. Rauschenbach
a
a
Institute of Cytology and Genetics, Russian Academy of Sciences, Siberian Division, Novosibirsk 630090, Russia
b
Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
c
Institute of Molecular Biology and Biotechnology, FORTH, 711-10 Heraklion, Crete, Greece Received 31 October 1999; received in revised form 31 December 1999; accepted 25 January 2000
Abstract
Juvenile hormone JH degradation was studied under normal and stress conditions in young and matured females of Drosophila melanogaster
strains having mutations in different genes involved in responses to stress It was shown that 1 the impairment in heat shock response elicits an alteration in stress-reactivity of the JH system; 2 the impairment JH reception causes a decrease
of JH-hydrolysing activity and of stress-reactivity in young females, while in mature ones stress reactivity is completely absent; 3 the absence of octopamine results in higher JH-hydrolysis level under normal conditions and altered JH stress-reactivity; 4
the higher dopamine content elicits a dramatic decrease of JH degradation under normal conditions and of JH stress-reactivity. Thus, the impairments in any component of the Drosophila stress reaction result in changes in the reponse of JH degradation
system to stress. The role of JH in the development of the insect stress reaction is discussed.
2000 Elsevier Science Ltd. All
rights reserved.
Keywords: Drosophila melanogaster ; ts403; Met; T
bh; ebony; Juvenile hormone; Stress reactivity
1. Introduction
Juvenile hormone JH, a sesquiterpenoid involved in the regulation of developmental transitions and repro-
duction in insects reviews: Riddiford and Ashburner, 1991; Nijhout, 1994; Wyatt and Davey, 1996, is well
known to play a main role in the development of the insect stress reaction reviews: Cymborowski, 1991 Rau-
schenbach 1991, 1997. Two other important compo- nents of this multi-faceted response are the metabolism
of biogenic amines, dopamine DA and octopamine OA, and the heat shock response HSR Orchard and
Loughton, 1981; Davenport and Evans, 1984; Woodring et al., 1989; Hirashima et al., 1993, 1999; Rauschenbach
et al. 1993, 1997; Rauschenbach, 1997; Sukhanova et al., 1997; Khlebodarova et al., 1998.
We have previously shown that the JH metabolic sys-
Corresponding author. Tel.: +
383-2-333-526; fax: +
383-2-331- 278.
E-mail address: kiselevabionet.nsc.ru N.E. Gruntenko.
0965-174800 - see front matter
2000 Elsevier Science Ltd. All rights reserved. PII: S 0 9 6 5 - 1 7 4 8 0 0 0 0 0 4 9 - 7
tem of wild type females of Drosophila melanogaster and D. virilis responds to stress conditions termed here
stressors with a decrease in JH-hydrolysing activity. Males do not respond to stressors in this manner
Rauschenbach et al. 1995, 1996. The metabolic sys- tems of DA and OA respond to stress, in both sexes, by
an increase in the amine content and by a decrease in the activity of their synthetic enzymes Rauschenbach et
al., 1993; Hirashima et al., 1999. We have also demon- strated that a mutation disturbing the development of the
stress reaction in D. virilis also elicits the impairment of HSR Khlebodarova et al., 1998.
How do impairments of the different components of the stress reaction, such as HSR and the metabolism of
DA and OA, affect JH metabolism in D. melanogaster females under normal and stress conditions? Previous
work has demonstrated that biogenic amines are involved in the regulation of JH biosynthesis and
secretion by the corpora allata and that the expression of some HSR genes is JH dependent Piulachs and
Belles, 1989; Thompson et al., 1990; Berger et al., 1992; Granger et al., 1996.
776 N.E. Gruntenko et al. Insect Biochemistry and Molecular Biology 30 2000 775–783
In this work, we analysed the mutations ts403, Met, T
bh and ebony e with respect to the response of JH- degradation system to stress. The recessive temperature
sensitive lethal mutation llts403 results in the failure of heat shock protein HSP83 and HSP35 to be
expressed, and a number of HSP70 proteins are only par- tially expressed Evgen’ev and Denisenko, 1990. Met
27
is a null allele of the Methoprene-tolerant gene that shows resistance to the toxic effects of both JH and a
JH analog, methoprene. The mechanism of the resistance appears to be altered JH receptionWilson and Fabian,
1986; Shemshedini and Wilson, 1990. Met
27
completely lacks Met transcript and is clearly a null allele Wilson
and Ashok, 1998. T bh
nM18
is a null mutation at the Tyr- amine
b-hydroxylase locus, which results in complete absence of the tyramine
β -hydroxylase protein and
blockage of octopamine biosynthesis Monastirioti et al., 1996. e is postulated to be the mutation of N-
b-alanyl dopamine synthetase
gene, based on the fact that e has twice as much DA as normal Hodgetts, 1972; Hodgetts
and Konopka, 1973; Ramadan et al., 1993. Here we asked whether these mutations would affect
the decrease in JH degradation occurring in D. mel- anogaster
when stressed. In order to answer this ques- tion, we studied the JH degradation in individuals of
ts403, n Met
27
, T bh
nM18
and Ste strains carring llts403, Met
27
, T bh and e mutations, respectively, under normal
and stress conditions, and compared their stress-reac- tivity calculated as percent change in JH hydrolysis
under stress compared to hydrolysis under normal conditions with that in a number of wild type and lab-
oratory strains.
We demonstrated 1 that ts403 females respond to stress by a decrease in JH degradation, as occurs in wild
type females, but that their stress-reactivity significantly differs from that of wild type; 2 that in young v Met
27
females, similar to wild type flies, JH hydrolysis is decreased upon stress, but their stress-reactivity is sig-
nificantly lower than in wild type; 3 that JH degra- dation is unaffected in older v Met
27
females under stress; 4 that T
bh
nM18
females show a significantly higher JH-hydrolysis level and different stress-reactivity
than does the wild type; and 5 that young Ste females demonstrate significantly lower JH-hydrolysis and
stress-reactivity, compared to the wild type.
2. Materials and methods
