RESUMO
The effect of the ubiquitous downregulation of insulin receptor (InR) gene expression on the metabolism of juvenile hormone (JH) and dopamine (DA) in young females of D. melanogaster under normal conditions and heat stress is studied. The activity ofJH degradation and alkaline phosphatase (ALP, an enzyme regulating DA synthesis) were used as indicators of JH and DA levels, respectively. We demonstrated that, under normal conditions, the ubiquitous inhibition of the InR gene expression in D. melanogaster females induced an increase in the JH degradation and ALP activity. As we have already shown, this is indicative of the decrease in the concentration of the above hormones. It was also found that the total inactivation of InR does not affect the initiation ofJ H and DA metabolic system response to heat stress; however, it does affect its intensity. Thus, the involvement of the insulin signaling pathway in the regulation of the JH and DA metabolism in Drosophila females was demonstrated in vivo under normal and stress conditions.
Assuntos
Regulação para Baixo , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Resposta ao Choque Térmico , Hormônios Juvenis/metabolismo , Receptores Proteína Tirosina Quinases/genética , Fosfatase Alcalina/metabolismo , Animais , Dopamina/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Feminino , Receptores Proteína Tirosina Quinases/metabolismoRESUMO
Tissue-specific inhibition of the expression of the D2-like dopamine receptor gene (DD2R) in the corpus allatum (CA), which is a gland that synthesizes the juvenile hormone (JH), was tested for effect on alkaline phosphatase (AP) activity and the intensity of the AP response to heat stress (stress reactivity) in female Drosophila melanogaster. AP activity and AP stress reactivity in transgenic females with lower DD2R expression in the CA were higher than in control flies. A pharmacological elevation in JH increased AP activity in females of the control strains. DD2R was assumed to mediate the inhibitory effect of dopamine of JH synthesis in the CA of D. melanogaster.
Assuntos
Fosfatase Alcalina , Regulação Enzimológica da Expressão Gênica , Hormônios Juvenis , Receptores de Dopamina D2 , Fosfatase Alcalina/genética , Fosfatase Alcalina/metabolismo , Animais , Animais Geneticamente Modificados , Corpora Allata/metabolismo , Dopamina/genética , Dopamina/metabolismo , Antagonistas dos Receptores de Dopamina D2 , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Feminino , Expressão Gênica , Temperatura Alta , Hormônios Juvenis/genética , Hormônios Juvenis/metabolismo , Receptores de Dopamina D2/genética , Receptores de Dopamina D2/metabolismo , Estresse Fisiológico/fisiologiaAssuntos
Dopamina/metabolismo , Drosophila/efeitos dos fármacos , Drosophila/metabolismo , Gonadotropinas/farmacologia , Acetiltransferases/metabolismo , Fosfatase Alcalina/metabolismo , Animais , Drosophila/crescimento & desenvolvimento , Proteínas de Drosophila/metabolismo , Ecdisterona/farmacologia , Feminino , Hormônios Juvenis/farmacologiaRESUMO
Alkaline phosphatase (AP) and N-acetyltransferase (NAT) activities were studied in 1-day-old Drosophila melanogaster females of the apterous56f (ap56f) strain, having an elevated level of the juvenile hormone (JH) and a decreased level of dopamine as a result of the mutation, and in the Canton S ancestral wild-type strain in the normal conditions and upon an experimental increase in JH titer. The AP and NAT activities in ap56f females were significantly lower than in Canton S females in the norm. JH application increased the AP activity of mutant females to the level characteristic to JH-treated wild-type females.
Assuntos
Acetiltransferases/genética , Fosfatase Alcalina/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/enzimologia , Proteínas de Homeodomínio/genética , Fatores de Transcrição/genética , Acetiltransferases/metabolismo , Fosfatase Alcalina/metabolismo , Animais , Animais Recém-Nascidos , Dopamina/metabolismo , Feminino , Hormônios Juvenis/metabolismo , Proteínas com Homeodomínio LIM , MutaçãoRESUMO
The effects of L-dihydroxyphenylalanine (L-DOPA) and 20-hydroxyecdysone (20E) were studied with respect to the content of dopamine (DA), intensity of the juvenile hormone (JH) degradation, and fecundity of the wildtype flies (Canton S) and JH-deficient apterous56f mutants (in young females, carrying this mutation, the levels of DA and 20E production were strongly increased). Fly feeding with L-DOPA proved to increase the level of DA in a dose-dependent manner and reduce JH degradation in 2-day-old females of both strains. Feeding with 20E produced the same effect. Treating the wild-type flies with 2.5 mg L-DOPA caused a 24-h delay in beginning of oviposition and reduction in fecundity throughout the experiment. An L-DOPA dose of 1 mg caused no such changes. An experimental increase in 20E titer led to reduced fecundity of the wild-type flies, though no delay in oviposition was observed. In mutant flies, an increase in DA and 20E levels accelerated beginning of oviposition and increased fecundity of young females, though the latter parameter was reduced in mature individuals. Thus, an increase in endogenous DA and 20E characteristic of young apterous56f females is assumed to be a compensatory response that leads to a higher JH titer and induction of vitellogenesis.
Assuntos
Proteínas de Drosophila/genética , Proteínas de Homeodomínio/genética , Mutação , Oviposição/genética , Fatores de Transcrição/genética , Vitelogênese/genética , Animais , Dopamina/genética , Dopamina/metabolismo , Dopaminérgicos/farmacologia , Proteínas de Drosophila/metabolismo , Drosophila melanogaster , Ecdisterona/farmacologia , Feminino , Proteínas de Homeodomínio/metabolismo , Hormônios Juvenis/genética , Hormônios Juvenis/metabolismo , Proteínas com Homeodomínio LIM , Levodopa/farmacologia , Masculino , Oviposição/efeitos dos fármacos , Reprodução/efeitos dos fármacos , Reprodução/genética , Fatores de Transcrição/metabolismo , Vitelogênese/efeitos dos fármacosAssuntos
Drosophila/efeitos dos fármacos , Drosophila/metabolismo , Ecdisterona/metabolismo , Octopamina/farmacologia , Animais , Drosophila melanogaster/efeitos dos fármacos , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Feminino , Masculino , Oxigenases de Função Mista/deficiência , Oxigenases de Função Mista/genética , Mutação , Octopamina/deficiência , Octopamina/genética , Octopamina/metabolismoRESUMO
Degradation of juvenile hormone and reproductive function during starvation and experimental increase of the juvenile hormone titer were studied in wild type and mutant D. virilis females incapable to respond to heat stress by changes in juvenile hormone metabolism and fertility. After 24-hour starvation, the females of both lines were characterized by a decreased level of juvenile hormone degradation, 24-hour delay of egg laying, increased egg laying within 3 h after the termination of starvation, and decreased fertility within three days. Application of exogenous juvenile hormone also led to a decreased level of its degradation and 24-hour arrest of egg laying. Experimental increase of the juvenile hormone titer before the beginning of starvation led to a sharply increased fertility (number of laid eggs and number of progenies) within the first 24 h after the termination of starvation. The dynamics of juvenile hormone degradation and of fertility were similar after starvation and upon application of the exogenous hormone. The role of juvenile hormone in the control of egg maturation and laying under stress conditions has been discussed.
