Biomedical subjects

E K Karpova

Publications and source records attributed to E K Karpova.

14 recordsLinked to original sources

PubMed2005

Effects of dopamine on juvenile hormone metabolism and fitness in Drosophila virilis.

The effects of dopamine (DA) on juvenile hormone (JH) metabolism and fitness (estimated as fecundity and viability levels under heat stress (38 degrees C)) in Drosophila virilis have been studied. An increase of DA level obtained by feeding with DA reduced fitness of wild-type (wt) flies under stress, and decreased JH degradation in young wt females while increasing it in sexually mature wt females. A decrease in DA levels resulted from 3-iodo-tyrosine treatment and caused a decrease in JH degradation in sexually mature wt and heat sensitive (hs) mutant females (DA level in hs females is twice as high in wt females). A dramatic decrease in viability under stress and fecundity under normal conditions in wt, but not hs, females was observed. 3-iodo-tyrosine treatment also reduced the number of oocytes at stages 8-14, delayed oocyte transition to stage 10 and resulted in the accumulation of mature eggs in wt females. It delayed maturation of wt, but not hs, males as well, but did not affect their fertility. This advances our understanding of the regulation of JH metabolism by DA in Drosophila and suggests a crucial role for the basal DA level in fitness.

Age Factors↗

PubMed2005

Juvenile hormone, 20-hydroxyecdysone and dopamine interaction in Drosophila virilis reproduction under normal and nutritional stress conditions.

To elucidate the role of the juvenile hormone (JH) in the control of Drosophila reproduction under stress, JH degradation, dopamine (DA) content and reproduction were studied upon 20E treatment in Drosophila virilis females of wild type (wt) and a mutant, with increased 20E level and decreased fertility, under normal and nutritional stress conditions. 20E treatment of wt flies for 7 days results in an increase of DA content in young females, but a decrease in mature females, a decrease of JH degradation in both young and mature females, an 1-day delay in onset of oviposition and a decrease of fecundity to the level typical of mutant flies. One day of 20E treatment in 7-day-old fed and starved flies results in a small decrease of JH degradation in the fed females and a great decrease in the starved ones. Fecundity decreases in the fed flies to the levels of the starved untreated flies in both wt and mutant strains. An oviposition arrest is observed in the treated and the untreated starved, but not in the treated fed, females of both strains. The data obtained suggest ecdysone control of JH metabolism mediated via DA.

Animals↗

PubMed2005

[The ecdysoneless1 gene regulates metabolism of the juvenile hormone and dopamine in Drosophila melanogaster].

The dopamine (DA) content and the level of juvenile hormone (JH) degradation were studied in females of the wild-type Canton S strain and the ecdysoneless1 (ecd1) mutant, which does not produce ecdysone at a restrictive temperature (29 degrees C). Exposure at the restrictive temperature considerably increased the JH-hydrolyzing activity and the DA content in five-day ecd1 females compared with flies of both strains growing at 19 degrees C and Canton S females exposed at 29 degrees C. In one-day ecd1 females, the level of JH degradation also increased at the restrictive temperature, but the DA content was low. The effect of ecdysone deficiency on the stress response in Drosophila melanogaster females was studied using changes in DA content and JH degradation were used as indices. The ecd1 mutation did not prevent the initiation of the stress response in females exposed at the restrictive temperature, but changed its intensity (stress reactivity). The interaction of 20-hydroxyecdysone with JH and DA in regulating Drosophila reproduction under normal conditions and in stress is discussed.

Animals↗

PubMed2004

The effect of mutations altering biogenic amine metabolism in Drosophila on viability and the response to environmental stresses.

Dopamine (DA) content, tyrosine decarboxylase (TDC) activity and survival were studied under normal and environmental stress conditions in the ste and e strains carrying ebony mutation increasing DA level and the octopamineless strain Tbetah(nM18) of Drosophila melanogaster. Wild-type strains Canton S and Oregon R, and strain p845 from which Tbetah(nM18) strain was derived were used as controls. Sexual dimorphism of TDC activity, DA content, and survival in flies of all D. melanogaster strains under study was found. Tbetah(nM18) mutation sharply reduced TDC activity in females, while ebony had no such effect. DA content and survival under heat stress in Tbetah(nM18) flies did not differ from those in the wild type. ste and e flies had drastically increased DA content under normal conditions, dramatically decreased survival under heat stress, but increased survival under starvation. DA content and survival under heat stress were also studied in the reciprocal hybrids (males) F(1) of the cross D. virilis strains 101 (wild type) and 147 with X-linked mutation, which significantly increases DA content. 147x101 males had a considerably higher DA content and lower survival than 101x147 ones. Individuals of all D. melanogaster strains under study developed the stress reaction, as judged by changes in TDC activity and DA levels. The role of biogenic amines in the stress reaction development and adaptation to environmental stresses in Drosophila is discussed. Arch. Insect Biochem. Physiol. 55:55-67, 2004.

Adaptation, Physiological↗

PubMed2004

The role of juvenile hormone in the control of reproductive function in Drosophila virilis under nutritional stress.

To investigate the role of juvenile hormone (JH) in the control of Drosophila reproduction under stress, JH degradation and reproduction were studied under nutritional stress and JH treatment in Drosophila virilis females of wild type (wt) and a heat stress (hs) mutant: this mutant does not respond to heat stress by alterations in JH metabolism and has decreased JH level and fertility under normal conditions. One day of starvation results in a decrease of JH degradation, a delay in oocyte maturation, degradation of early vitellogenic egg chambers, accumulation of mature oocytes and a 24 h oviposition arrest in both wt and hs females. A fertility decrease was observed in both wt and hs females 24 h following the end of starvation. JH treatment leads to a decrease of JH degradation and an arrest of oviposition for 24 h in fed females. JH treatment prior to starvation seems to protect some oocytes from resorption: in JH-treated wt females, fertility increases rapidly following the end of starvation. The dynamics of JH degradation and fertility are similar following starvation and JH treatment. The role of JH in the accumulation of mature oocytes and the delay of oviposition under stress are discussed.

Animals↗

PubMed2002

Stress response in Drosophila melanogaster strain inactive with decreased tyramine and octopamine contents.

Juvenile hormone hydrolysis, tyrosine decarboxylase activity, dopamine content and fitness (viability and fertility) were studied under normal and stress conditions in the adults of Drosophila melanogaster inactive strain carrying a mutation that decreases tyrosine decarboxylase activity and results in the lower contents of tyramine and octopamine. A sexual dimorphism of tyrosine decarboxylase activity, dopamine level and survival under heat stress in inactive flies was found. inactive adults showed higher dopamine levels and lower survival levels under heat stress as compared to wild type (Canton S) adults. Juvenile hormone degradation is decreased in young and increased in mature inactive females as compared to wild type. Fertility of the inactive strain did not differ from that of wild type strain under normal conditions, but after heat exposure the dynamics of its restoration was different. inactive females were found to develop the stress reaction, with juvenile hormone degradation, tyrosine decarboxylase activity, dopamine content and fertility levels used as the reaction indicators.

Animals↗

PubMedDate not supplied