[The dopamine system stress reaction in adults of Drosophila virilis is controlled by genes of Chromosome 6]. / Stress-reaktivnost' sistemy dofamina u imago Drosophila virilis kontroliruetsia genom khromosomy 6.

A linkage group of the gene responsible for changes of DA titer under stress in adults of D. virilis was determined. Line 160 of D. virilis, all autosomes of which bear visible recessive mutations, was used as an analyzer. Flies of lines 160 and 147 were shown to differ in DA content under normal conditions and in the way DA metabolic system reacts to stress. Among the offspring of the analyzing cross, groups of flies were found with one testable autosome from line 147 and all other chromosomes from line 160. Results of the DA titer measurements in flies of these groups under stress conditions have proved that the gene in question is linked to chromosome 6.

[Some regularities in the genetic control of the stress reaction in Drosophila]. / O nekotorykh zakonomernostiakh geneticheskogo kontrolia stress-reaktsii drozofily.

The heat-shock response was studied in Drosophila virilis strains with normal and impaired neurohormonal stress reaction. Flies from the latter strain were shown to have the impaired heat-shock response. In this strain, transcription of the heat shock gene hsp83 is reduced and synthesis of all heat shock proteins is suppressed. The neurohormonal stress reaction (status of dopamine, octopamine, and juvenile hormone metabolic systems) was examined in D. melanogaster strains having normal and impaired heat-shock response. The impairment of this response did not prevent the development of the stress reaction: in flies of both strains, the stress exposure resulted in an increase in the dopamine content and in a decrease in the activity of tyrosine decarboxylase (the first enzyme of dopamine synthesis) and in the level of juvenile hormone degradation. However, stress reactivity in mutant individuals differed from that in flies that did not carry stress-related mutations.

[The heat-shock reaction is disturbed in a Drosophila virilis strain incapable of a neurohormonal stress reaction]. / Reaktsiia teplovogo shoka narushena u ne sposobnoi k neirogormonal'noi stress-reaktsii linii Drosophila virilis.

Cellular stress response was investigated in two lines of D. virilis: wild type and line with disturbed neurohormonal stress-reaction. Analysis of proteins, synthesized in salivary glands of larvae of both lines under heat stress, revealed malfunction in heat shock reaction of mutant specimen. This malfunction expresses in decreased level of heat shock protein synthesis. Analysis of electrophoretic spectra of proteins from homogenates of imagoes of both lines maintained under normal conditions and those exposed to heat (38 degrees C, 60 min.) revealed correlation between protein spectrum and physiological state of the organism. Interlinear differences by proteins spectra in normal condition, controlled by a single gene (or by block of closely linked genes), were found. The question if there is a common genetic control for the neurohormonal stress-reaction and cellular stress response is discussed.

Stress-reactivity of a Drosophila melanogaster strain with impaired juvenile hormone action.

Met(27) is a null allele of the Methoprene-tolerant gene of D. melanogaster that shows resistance to the toxic effects of both juvenile hormone (JH) and a JH analog, methoprene. The mechanism of resistance appears to be altered JH reception. We measured fertility, JH-hydrolyzing activity, and dopamine (DA) levels in Met(27) and Met(+) flies under normal (25 degrees C) and heat-stress (38 degrees C) conditions. We show that under normal conditions Met(27) females have JH-hydrolyzing activity and fertility lower than Met(+), but DA content did not differ between the two strains. At 38 degrees C Met(27) flies show no impairment in JH-hydrolyzing activity in response to stress, but they do show lower DA levels and impaired reproduction. The results with Met(27) are consistent with the previous hypothesis that the alteration in fertility that follows heat stress in D. melanogaster could result from alteration in the JH endocrine system.

Prolonged negative selection of Drosophila melanogaster for a character of adaptive significance disturbs stress reactivity.

The metabolism of juvenile hormone by JH-esterase and JH-epoxide hydrolase, and octopamine by tyrosine decarboxylase were studied under normal and stress conditions in flies of two related lines of D. melanogaster. One was selected for high (HA line) and another for low (LA line) male sexual activity for more than 700 generations. It was demonstrated that prolonged selection for low male sexual activity results in considerable changes in both systems. Tyrosine decarboxylase activity in males and females of the LA line was sharply reduced as compared with those of the HA and control Canton-S lines; JH-esterase and JH-epoxide hydrolase activities were decreased in females, and not in males, of the LA line. It was demonstrated that the response of both metabolic systems to heat stress is impaired in individuals of the LA line: the system of juvenile hormone metabolism does not respond to stress, and that of octopamine metabolism is decelerated. The role of juvenile hormone metabolism in male reproductive function is discussed.

[Genes, regulating activity of alkaline phosphatase and tyrosine decarboxylase in Drosophila virilis, linked to chromosome 6]. / Geny, reguliruiushchie aktivnost' shchelochnoi fosfatazy i tirozindekarboksilazy u Drosophila virilis, stsepleny s khromosomoi 6.

The linkage group of genes controlling alkaline-phosphatase (AP) and tyrosine-decarboxylase (TDC) activities in Drosophila virilis adults was determined. D. virilis strain 160, with all autosomes marked with recessive morphological mutations, was used for the analysis. AP and TDC activities were significantly higher in strain 160 than in strain 147. The analysis of F2 hybrids, which carried one chromosome (one or both homologues) of strain 147 and the rest of strain 160, allowed the assignment of the genes controlling AP and TDC activities in D. virilis adults to chromosome 6.

[Genes, controlling the response of the juvenile hormone degradation system to stress in the Drosophila virilis imago, linked to chromosome 6]. / Gen, kontroliruiushchii otvet sistemy degradatsii iuvenil'nogo gormona na stress u imago Drosophila virilis, stseplen s khromosomoi 6.

Chromosome localization of the gene controlling the stress response of DFP-sensitive juvenile hormone (JH) esterase in females of Drosophila virilis was conducted. Line 160 of D. virilis carrying recessive markers on all chromosomes was used as a tester. Mature females of line 160 were shown to exhibit a high level of JH hydrolysis; these flies responded to stress by a sharp decrease in JH hydrolysis. Flies from line 147 lacked this response. Thus, mature females of lines 160 and 147 had different levels of JH hydrolysis under heat stress. F2 hybrids that inherited one chromosome pair from flies of line 147 and the remaining chromosomes, from flies of line 147 were analyzed. This analysis showed that the D. virilis gene controlling the stress response of the JH degradation system is linked with chromosome 6.

[Selection for sex behavior changes the metabolism of juvenile hormone in Drosophila melanogaster]. / Selektsiia po polovomu povedeniiu izmeniaet metbolizm iuvenil'nogo gormona u Drosophila melanogaster.

The metabolism of juvenile hormone (JH) was studied in two lines of Drosophila melanogaster selected for differences in mating behavior. The lines were tested under normal conditions and after short-term heat shock. Females of the HA line (selected for high male mating activity) were shown to exhibit a high level of JH hydrolyzing activity under normal conditions. By contrast, females of the LA line (selected for low male mating activity) and males of both lines had a low level of JH hydrolysis. Stress exposure resulted in a decrease of JH hydrolysis in females of the HA line; this effect was absent in females of the LA line and males of both lines.