[The Antioxidant and Geroprotective Properties of an Extract of Mountain Ash (Sorbus aucuparia L.) Fruits].

Plant polyphenols are characterized by a wide range of biological activities, including antioxidant properties, and have a high geroprotective potential. The purpose of this work was to investigate the effect of the extract of rowan berries (Sorbus aucuparia L.) on the lifespan and stress resistance of Drosophila melanogaster with the identification of possible mechanisms of its biological activity. It has been established that an ethanol extract of S. aucuparia berries, the main components of which are rutin and cyanidin-3-rutinoside, has a pronounced antioxidant activity in vitro. At the same time, treatment with rowan berry extract increased the resistance of D. melanogaster males to starvation, but reduced resistance to hyperthermia. In females, the extract reduced resistance to oxidative stress but increased resistance to hyperthermia. The effects of rowan berry extract on longevity depended both on its concentration and on the sex of fruit flies. In response to treatment with rowan berry extract, D. melanogaster males and females showed slight differences in the background level of expression of cellular stress response genes, including heat shock genes (hsp27, hsp68, and hsp83), oxidative stress resistance genes (hif1, nrf2, and sod1), circadian rhythm genes (clk and per), and the longevity gene sirt1, which may explain the differences in the observed effects.

[Drosophila melanogaster Lifespan Is Regulated by nejire Gene Expression in Peripheral Tissues and Nervous System].

Histone acetyltransferases of the CBP/p300 family are involved in transcriptional regulation and many biological processes (cell proliferation and differentiation, development, and regulation of the stress response and metabolism). Overexpression and knockdown of the nejire (nej) gene (codes for an ortholog of human CBP/p300 proteins) in various tissues (the fat body, intestine, and nervous system) and at various stages of the life cycle (throughout all developmental stages or in adulthood only) were tested for effect on lifespan in the fruit fly Drosophila melanogaster. The activation of nej exerted a positive or a negative effect on the lifespan, depending on the induction mode and the sex. A 6-15% greater lifespan was observed in females with conditional overexpression of nej in the intestine and constitutive overexpression of nej in the nervous system. A decrease (to 44%) or lack of significant changes in lifespan was detected in all other cases observed. In addition, stress response genes (Sod1, Gadd45, Hsp27, Hsp68, and Hif1) were regulated by nej activation. nej knockdown caused a pronounced negative effect on the D. melanogaster lifespan in most variants of the experiment.

[Key Molecular Mechanisms of Aging, Biomarkers, and Potential Interventions].

The mechanisms of aging are described at the molecular, cell, tissue, and systemic levels. Primary age-dependent molecular lesions activate the cell stress response to compensate for the resulting defects, but the mechanisms that recover and maintain homeostasis are gradually deteriorated. When the amount of errors reaches a critical threshold in regulatory networks, a phase transition from health to disease occurs at the systemic level. The review considers the approaches to quantitative assessment of the aging process (biomarkers of aging) and promising interventions to slow down the aging process and to reduce the risk of age-dependent diseases.

[The relationship of lifespan with characteristics of life cycle and stress resistance in 12 species of Drosophila].

In the present study, we investigated the relationship of lifespan with different characteristics of the life history (length of the developmental period, imago body weight, fecundity) and stress resistance (response to oxidative stress, hyperthermia, starvation, and ionizing radiation) in flies of 12 species of the Drosophila genus. It was shown, that D. virilis has the highest maximum lifespan, but the lifespan of D. kikkawai was lowest. The investigated features have a positive (length of the developmental period, imago body weight, stress resistance) or negative (fecundity) correlation with species lifespan. Apparently, the observed differences are caused by adaptations of the species to different environmental conditions of their natural habitat, and lifespan is a key indicator of integrative fitness, reflecting the viability and various characteristics of life history and stress resistance.

Geroprotective effects of activation of D-GADD45 DNA reparation gene in Drosophila melanogaster nervous system.

The expression of D-GADD45 gene involved in DNA reparation in Drosophila melanogaster decreases with age. Overexpression of D-GADD45 in the drosophila nervous system prolongs the median and maximum life span without deterioration of the quality of life parameters (fertility and neuromuscular activity). The life span prolongation effect is due to more effective DNA reparation, as spontaneous level of DNA aberrations in the nerve tissue of larvae with D-GADD45 overexpression is reduced significantly.

Effect of PARP-1 overexpression and pharmacological inhibition of NF-kB on the lifespan of Drosophila melanogaster.

Age-dependent accumulation of genome rearrangements leads to cellular senescence, overall aging and lifespan decreasing of the organism. In this respect, it is important to study the effect of overexpression of DNA repair genes on the lifespan and aging parameters (rates of age-related decline of fertility and locomotor activity). The present work investigates how the overexpression of the PARP-1 gene, which is involved in various mechanisms of DNA repair (base excision repair and DNA double-strand breaks repair), combined with a pharmacological inhibition of the NF-kB transcription factor that controls the genes of inflammatory response, affects the lifespan of Drosophila melanogaster. It is demonstrated that in males, constitutive activation of PARP-1 overexpression in the nervous system throughout the lifetime results in reduced median (by 14%) and maximum (by 8%) lifespan, whereas in females the median (by 14%) and maximum (by 20%) lifespan increases. Activation of PARP-1 overexpression in the imago (conditionally) results in extension of the median (by 3-16%) and the maximum (by 10-15%) lifespan in females and males, respectively. The lifespan increase in females with PARP-1 conditional overexpression was accompanied by decrease of fertility. Selective pharmacological inhibition of transcription factor NF-kB with pyrrolidine dithiocarbamate increases the median (by 13-20%) and the maximum (by 11-14%) lifespan in females and males, respectively. No synergic effect between conditionally activated PARP-1 expression and NF-kB inhibition is observed. The geroprotective effect of PARP-1 overexpression depends on the sex and the life history stage of overexpression induction.

Radiation hormesis and radioadaptive response in Drosophila melanogaster flies with different genetic backgrounds: the role of cellular stress-resistance mechanisms.

The purpose of this work is to investigate the role of cellular stress-resistance mechanisms in the low-dose irradiation effects on Drosophila melanogaster lifespan. In males and females with the wild type Canton-S genotype the chronic low dose irradiation (40 cGy) induced the hormetic effect and radiation adaptive response to acute irradiation (30 Gy). The hormesis and radioadaptive responses were observed in flies with mutations in autophagy genes (atg7, atg8a) but absent in flies with mutations in FOXO, ATM, ATR, and p53 homologues. The hormetic effect was revealed in Sirt2 mutant males but not in females. On the contrary, the females but not males of JNK/+ mutant strain showed adaptive response. The obtained results demonstrate the essential role of FOXO, SIRT1, JNK, ATM, ATR, and p53 genes in hormesis and radiation adaptive response of the whole organism.

Increase of Drosophila melanogaster lifespan due to D-GADD45 overexpression in the nervous system.

The GADD45 protein family plays an important role in stress signaling and participates in the integration of cellular response to environmental and physiological factors. GADD45 proteins are involved in cell cycle control, DNA repair, apoptosis, cell survival and aging, and inflammatory response by complicated protein-protein interactions. In Drosophila melanogaster a single D-GADD45 ortholog (GG1086) has been described. Our data show that overexpression of the D-GADD45 gene in the nervous system leads to a significantly increase of Drosophila lifespan without a decrease in fecundity and locomotor activity. The lifespan extension effect is more pronounced in males than in females, which agrees with the sex-dependent expression of this gene. The longevity of D. melanogaster with D-GADD45 overexpression is apparently due to more efficient recognition and repair of DNA damage, as the DNA comet assay showed that the spontaneous DNA damage in the larva neuroblasts is reduced with statistical significance.

[FOXO tanscription factor role in radiation adaptive response and hormisis in Drosophila melanogaster].

Previously we put forward a hypothesis about the role of FOXO-dependent mechanisms of stress-response gene activation after irradiation in radiation hormesis (Moskalev, 2008). To testify this assumption we analyze the influence of gamma-irradiation on duration of larvae development and imago lifespan in Drosophila strains with different FOXO function activity. We revealed that in FOXO hypomorphic allele homozygote strains the hormesis and adaptive response (increasing of larvae stage duration and longevity) were absent, in contrast to B wild type strain Canton-S and FOXO-heterozygotes.

[Pharmacological PI 3-kinase inhibitors induce radioprotective effect in Drosophila melanogaster imago].

Phosphatidylinositol 3-kinase (PI3K) signaling cascade is involved in many cell processes that are required for radioresistance, including proliferation, survival, growth, metabolism, and death. At the whole organism level PI3K signaling cascade is involved in lifespan control. In this study the contribution of PI3-signaling cascade to radioresistance of Drosophila melanogaster imago was investigated. It is shown that pretreatment with Pl3-kinase specific inhibitor LY294002 (5, 100 micromol/l) and wortmannin (5 micromol/1) leads to increase of male and female survival after acute irradiation in dose of 30 Gy. The obtained results demonstrate that PI3K specific inhibition induces radioprotective effect on Drosophila melanogaster imago.

Pharmacological inhibition of phosphoinositide 3 and TOR kinases improves survival of Drosophila melanogaster.

Recent progress in our understanding of genetic mechanisms of aging and longevity provides an opportunity to select some enzymes as targets for pharmacological correction. The phosphoinositide 3-kinase (PI3K) and TOR-kinase cascades are affected in some long-lived mutants of different animals, such as nematodes and mice. The purpose of this study was to investigate the geroprotector efficiency of the inhibitors of enzymes that are known to be affected in long-lived mutants. Experimental animals were exposed to low dozes of LY-294002 (5 microM), wortmannin (0.5 microM), and rapamycin (0.5 microM) separately during their lifetimes. We have shown that the specific PI3K inhibitors (LY-294002 and wortmannin) and the TOR-kinase inhibitor rapamycin slightly increase the median and maximal lifespan of the fruit fly, Drosophila melanogaster.

[Low-dose rate irradiation induced hormesis, hypersensitivity and adaptive response in Drosophila melanogaster of radiosensitive strains].

We have studied the adaptive response after chronic low dose irradiation (2.5 mGy/h) in wild type Drosophila melanogaster strains (Canton-S and Oregon-R), as well as mutant strains on DNA damage sensing (mei-41), DNA repair (mus209, mus210, mus309, rad54) and free radicals detoxification (sod). The effects of irradiation on the prolongation of the larval stage, pupa lethality, and imago whole body weight have been analyzed. The high dose irradiation (30 Gy, 0.05 Gy/s) induced prolongation of the prepupal period and lethality in all wild type and mutant strains under investigation. The chronic low dose irradiation resulted in shortening of the larval development period (hormetic effect) was observed in wild type (Oregon-R) and mutant (mus209) strains (absorbed dose was 20 cGy) of Drosophila. At the same time these strains demonstrated the hormetic effect after chronic low dose irradiation. The hypersensitivity effect was found in sod and rad54 larvae (20 cGy, prolongation of the prepural period), and rad54 and mei-41 pupa (40 cGy, increase of death rate). The larvae of hypersensitive strains and pupa of all strains under investigation did not have the adaptive response. The chronic irradiation in 6 and 60 cGy with the dose rate of 0.25 and 2.5 mGy/h induced the hormetic effect (imago whole body weight enhancement) Canton-S. The obtained results suggest the important role of free radical detoxification, of DNA damage sensing, and of DNA repair mechanisms in the whole organism radiation induced effects. The appearance of the adaptive response depends on the investigated effect and developmental stage of fly.

[Adaptive response on life span alteration in Drosophila melanogaster strains with mutations in heat shock factor and heat shock proteins genes].

The survival adaptive response (the life span alteration) induced by low-level radiation was studied in Drosophila using wild type strain (Canton-S) and strains mutant in genes of heat shock factor Hsf (1-4 alleles) and heat shock proteins (Hsp70Ba(304), Hsp83(e6A), Hsp22(EY09909)). The inductive doses of gamma-radiation were 6 and 60 cGy at a dose of 0.017 and 0.17 cGy/h. As a challenging dose we used feeding of flies by 20 mM paraquat in 5% sucrose solution during 24 h. The adaptive response was induced by chronic low dose irradiation in all experimental variants except Hsf4 and Hsp70Ba(304) homozygous strains. In Hsp22 homozygous strain the adaptive response was found only in males but wasn't in females. Thus the Drosophila strain homozygous on Hsp and Hsfmutations do not demonstrate the adaptive response in the most of studied variants. These results indicate the direct involvement of Hsp and Hsf genes to the formation of adaptive response.

[Life span sexual dimorphism].

The most of the studied species have extended life span of females compared to males. This is due to increased extrinsic (behavioral-independent) and intrinsic (age-related) mortality ratio of males. Evolutionary theory predicts that high rate of extrinsic mortality should increase the rate of aging. We suggest testing the evolutionary theory by estimation of male life span in Drosophila sex behavioral mutants. The intrinsic mortality ratio may be affected by hormonal signals from gonads, which modify insulin/IGF-1 signaling by sex-specific mode. Investigation of life span in flies mutant in insulin/IGF-1 signaling pathway may help to understand the molecular mechanism of sex differences in lifespan.

[Longevity extension by specific inhibition of pI3K in Drosophila melanogaster].

Mutational decreasing of phosphoinositide 3-kinase (PI3K) cascade genes function leads to a life span increase in a lot of model organisms. However the geroprotector effect of pharmacological inhibition of PI3K has not yet been studied. In this connection, we analyzed life span of D. melanogaster wild type laboratory strain Canton-S after treatment by LY-294002 (5 microM), that is a specific inhibitor of PI3K at preimaginal stages of development and imago. It is shown that imago feeding by LY-294002 results in lifespan increase. The median lifespan increases by 14% in males and by 14.3% in females, the maximal--by 22.5% in males, and by 16.3% in females. The obtained results demonstrate that specific inhibition of P13K has a geroprotector effect on D. melanogaster imago.

[The influence of dysgenic sterility on sexual dimorphism of life span in Drosophila Melanogaster].

It was analyzed the life span of fertile and sterile (as a result of P-M hybrid dysgenesis) flies. In investigation the F1 hybrids from the crosses of wild type Drosophila strains Canton-S (M) and Harwich (P) were used. Reciprocal crosses of these strains enable to obtain fertile and sterile hybrids with the same genotypes. It is shown the reduction of life span in sterile females and an increase of life span in sterile males. The obtained results indicate that signals from male and female gonads have opposite effects on longevity. Whereas in fertile flies sexual dimorphism that manifested in greater female longevity was observed, in sterile flies females had duration of life close to males. The leveling of the life span characteristics in sterile females and males shows that mechanism of sexual life span differences relates to reproductive system. It seems to be possible that testicles induce some mechanism that shortens males life span, and ovaries are the source of the signal extending females life span.

[The influence of ecdysone-containing phytopreparations on life span of Drosophila melanogaster strains depending on the genotype].

The longevity of Drosophila strains has been investigated after treatment by a hormone 20-hydroxyecdysone (80% solution) and a phytoecdysteroid-containing metaverone preparation (contains 5-7% of 20-hydroxyecdysone) in preimaginal stages of development. It is shown, that life expectancy of ecdysone-deficient woc strain exceeds life expectancy of wild type Canton-S strain by 46%, whereas ecdysone or metaverone treatment removes these distinctions. At the same time, treatment by ecdysteroid-containing preparations of Canton-S has not induced any essential alteration of life span. Thus, the new ageing gene woc has been discovered, the woc mutation essentially increases the life span of Drosophila, and its effect is mediated by a hormone 20-hydroxyecdysone and has the threshold corresponding natural physiological concentration of this hormone in an insect organism. The data have confirmed the conception of "antagonistic pleiotropy" according to which only mutations having advantages during the prereproductive and reproductive period are fixed in evolution, and their negative effect is delayed up to a postreproductive stage of life cycle. As a result we can see accumulation with age of structural and functional damages which increase probability of death. Indeed, genes of ecdysone synthesis play fundamentally important role in early development and sexual reproduction of insects, however essentially reduce their life span.

[Genetic aspects of the irradiation in small doses of laboratory lines and experimental populations Drosophila melanogaster].

One of explanations of revealed effects of small doses of an irradiation is induced genetic instability on which background there is a realization of the various radiobiological reactions resulting as to stimulation, and significant oppression of the vital functions of a cell or an organism. In work the given estimations of consequences of an irradiation in small doses of mutant lines of the drosophila are submitted. Paramount value in definition of their size and an orientation of reaction of a genotype is supposed, that, have processes leaders to change of activity of mobile genetic elements and programmed destruction of a cell.

[The genetic effects induced by an irradiation in low doses at Drosophila melanogaster].

This article generalizes the results received by authors in researches of genetic effects of an irradiation for Drosophila. It is supposed, that the main effect of low intensity irradiation is connected with the induced genetic instability on which background the realization of effects of a different direction is possible.