Decreased Life Span Research Articles

Extension of life span by down-regulation of enzymes catalyzing tryptophan conversion into kynurenine: Possible implications for mechanisms of aging.

The end products of catabolism of tryptophan (Trp), an essential amino acid, are known to affect mechanism(s) of aging, a neurodegenerative condition. This review focuses on the possible role of the initial step of Trp catabolism, kynurenine (Kyn) formation from Trp, in aging mechanism(s). Rate-limiting enzymes of Trp conversion into Kyn are tryptophan 2,3-dioxygenase 2 (TDO) or indoleamine 2,3-dioxygenase (IDO). Aging is associated with up-regulated production of cortisol, an activator of TDO, and pro-inflammatory cytokines, inducers of IDO. The other rate-limiting enzyme of Kyn formation from Trp is ATP-binding cassette (ABC) transporter that regulates Trp availability as a substrate for TDO. Inhibitors of TDO (alpha-methyl tryptophan) and ABC transporter (5-methyltryptophan) extended life span of wild-type Drosophila. Life span prolongation was observed in TDO knockdown of Caenorhabditis elegans and in TDO or ABC transporter-deficient Drosophila mutants. Down-regulation of enzymes catalyzing Kyn conversion into kynurenic acid (KYNA) and 3-hydroxykynurenine decreases life span. Considering that down-regulation of Methuselah (MTH) gene prolonged life span, aging-accelerating effect of KYNA, a GPR35/MTH agonist, might depend on MTH gene activation. Mice treated with TDO inhibitor, benserazide, an ingredient of anti-Parkinson medication carbidopa, and TDO-deficient Drosophila mutants were resistant to inducement of aging-associated Metabolic Syndrome by high-sugar or high-fat diets. Up-regulation of Kyn formation was associated with accelerated aging and increased mortality in human subjects. Trp-Kyn pathway is evolutionary conserved (from yeasts, through insects, worms, vertebrates to humans). Further studies might explore possible antiaging effect of down-regulation of Kyn formation from Trp by dietary, pharmacological, and genetic interventions.

Increased Fibrosis in White Adipose Tissue of Male and Female bGH Transgenic Mice Appears Independent of TGF-β Action.

Fibrosis is a pathological state caused by excess deposition of extracellular matrix proteins in a tissue. Male bovine growth hormone (bGH) transgenic mice experience metabolic dysfunction with a marked decrease in lifespan and with increased fibrosis in several tissues including white adipose tissue (WAT), which is more pronounced in the subcutaneous (Sc) depot. The current study expanded on these initial findings to evaluate WAT fibrosis in female bGH mice and the role of transforming growth factor (TGF)-β in the development of WAT fibrosis. Our findings established that female bGH mice, like males, experience a depot-dependent increase in WAT fibrosis, and bGH mice of both sexes have elevated circulating levels of several markers of collagen turnover. Using various methods, TGF-β signaling was found unchanged or decreased-as opposed to an expected increase-despite the marked fibrosis in WAT of bGH mice. However, acute GH treatments in vivo, in vitro, or ex vivo did elicit a modest increase in TGF-β signaling in some experimental systems. Finally, single nucleus RNA sequencing confirmed no perturbation in TGF-β or its receptor gene expression in any WAT cell subpopulations of Sc bGH WAT; however, a striking increase in B lymphocyte infiltration in bGH WAT was observed. Overall, these data suggest that bGH WAT fibrosis is independent of the action of TGF-β and reveals an intriguing shift in immune cells in bGH WAT that should be further explored considering the increasing importance of B cell-mediated WAT fibrosis and pathology.

Combustion and Stubble Burning: A Major Concern for the Environment and Human Health

Combustion is an essential process for humanity, but it has created turbulence in society due to the pollutant emissions from the partial completion of its process and its byproducts. The regular population is unaware of the repercussions being faced in terms of health deterioration, product quality degradation, biodiversity loss, and environmental harm. Although strategic planning against the effects is being applied sideways by the authorities to the local population and industrial facilities, the awareness in the local population is still minimal. The indicators for bioremediation being required, observed through increased sales of pharmaceutical medicines and supplements, air filters, and new techniques, include smog, elevation in respiratory disease, health immune system deterioration, decreasing life span, increasing mortality rate, and degradation in the food and water quality. This article gives a brief overview of the problems being faced due to uncontrolled combustion activities, the sources of pollutants, their creation, emission, and dispersal process, along with the mitigation techniques developed to overcome the after-effects on human health and environment.

The antioxidant effect of chitosan on virgin and mated Drosophila females

Mating causes decreased life span and oxidative damage in female Drosophila. We investigated the effect of under mating and virginity oxidative stress-induced damage and soluble Chitosan (Ch) supplementation. It was determined as antioxidant capacity (TAS) and total oxidation (TOS), triacylglycerol (TAG), protein and glycogen concentration of Ch (1–20 mg/mL) on young-old mated and virgin flies (Drosophila melanogaster). We were found that females of mating and aging groups feeding with Ch were lower levels of stress. Feeding with high concentrations of Ch in aging decreased the amount of TAG and glycogen, while increasing the amount of protein. The study suggests that higher antioxidant defenses in virgin and old females confer resistance to oxidative stress, because of feeding with 20% Ch. Data shows that mating status affects fly physiology and metabolism in free radical processes.

Why supercontinents became shorter lived as the Earth evolved

Periodic assembly and break-up of supercontinents since at least two billion years ago (Ga), dubbed the supercontinent cycle, provides the first-order tectonic control on the evolution of the Earth System including episodic orogenic events, mineralization, the formation and closure of oceans and superoceans, and even the evolution of life. However, the lifespan of the supercontinents appears to decrease with time, from ∼300 million years (Myr) for Nuna/Columbia, to 200–250 Myr for Rodinia and ∼150 Myr for the youngest supercontinent Pangaea. To understand what caused such a secular decrease in supercontinental lifespan, we conduct 3-D geodynamic modeling using realistic tectonic settings. The results show that the yield stress of newly formed orogens during the assembly of a supercontinent provides the dominant control on the lifespan of the supercontinent, implying that the yield stress of young orogens becomes lower with time. We hypothesize that the decreasing mantle temperature due to Earth’s secular cooling might have caused new orogens to become weaker.

Azot expression in the Drosophila gut modulates organismal lifespan

ABSTRACT Cell Competition emerged in Drosophila as an unexpected phenomenon, when confronted clones of fit vs unfit cells genetically induced. During the last decade, it has been shown that this mechanism is physiologically active in Drosophila and higher organisms. In Drosophila, Flower (Fwe) eliminates unfit cells during development, regeneration and disease states. Furthermore, studies suggest that Fwe signaling is required to eliminate accumulated unfit cells during adulthood extending Drosophila lifespan. Indeed, ahuizotl (azot) mutants accumulate unfit cells during adulthood and after physical insults in the brain and other epithelial tissues, showing a decrease in organismal lifespan. On the contrary, flies carrying three functional copies of the gene, unfit cell culling seems to be more efficient and show an increase in lifespan. During aging, Azot is required for the elimination of unfit cells, however, the specific organs modulating organismal lifespan by Azot remain unknown. Here we found a potential connection between gut-specific Azot expression and lifespan which may uncover a more widespread organ-specific mechanism modulating organismal survival.

A screen of small molecule and genetic modulators of life span in female Drosophila identifies etomoxir, RH5849 and unanticipated temperature effects

ABSTRACT Mifepristone increases life span in female Drosophila melanogaster, and its molecular target(s) remain unclear. Here small molecule and genetic interventions were tested for ability to mimic mifepristone, or to decrease life span in a way that can be rescued by mifepristone. Etomoxir inhibits lipid metabolism, and significantly increased life span in virgin and mated females, but not males, at 50 µM concentration. Pioglitazone is reported to activate both mammalian PPARγ and its Drosophila homolog Eip75B. Pioglitazone produced minor and inconsistent benefits for female Drosophila life span, and only at the lowest concentrations tested. Ecdysone is a Drosophila steroid hormone reported to regulate responses to mating, and RH5849 is a potent mimic of ecdysone. RH5849 reduced virgin female life span, and this was partly rescued by mifepristone. Mifepristone did not compete with RH5849 for activation of an ecdysone receptor (EcR)-responsive transgenic reporter, indicating that the relevant target for mifepristone is not EcR. The conditional GAL4/GAL80ts system was used in attempt to test the effect of an Eip75B RNAi construct on female life span. However, the 29°C temperature used for induction reduced or eliminated mating-induced midgut hypertrophy, the negative life span effects of mating, and the positive life span effects of mifepristone. Even when applied after mating was complete, a shift to 29°C temperature reduced mating-induced midgut hypertrophy by half, and the life span effects of mating by 4.8-fold. Taken together, these results identify promising small molecules for further analysis, and inform the design of experiments involving the GAL4/GAL80ts system.

Ozone reduces lifespan and alters gene expression profiles in Rhyzopertha dominica (Fabricius).

Rhyzopertha dominica is one of the most important stored grain pests that seriously damage rice and wheat. At present, the method of controlling stored grain pests mainly relies on insecticide fumigation. However, the excessive use of pesticides not only leaves pesticide residues, with harmful effects on human health and the environment, but also induces insect resistance. Ozone is a strong oxidant with the characteristics of easy decomposition and without residue. Although ozone has been widely used in the food industry in recent years, research on the control of stored grain pests is limited. In this research, we used ozone treatment to control R. dominica adults and explore the molecular mechanisms that affect them. Here, we found that ozone treatment on R. dominica adults could decrease life span and increase malondialdehyde (MDA) content, as well as reduce activity of total superoxide dismutase (SOD) and catalase (CAT). Using RNA-seq technology, we identified 641 genes that were differentially expressed between ozone-treated and control R. dominica adults [fold-change of ≥ 2 (q-value < 5%)]. When comparing ozone treatment with control R. dominica adults, 330 genes were significantly upregulated and 311 were downregulated. RT-qPCR confirmed that 11 genes were differentially expressed in ozone-treated and control R. dominica adults. These genes were involved in insect cuticle protein and antioxidant system. This research showed that ozone treatment could reduce the lifespan of R. dominica through antioxidant system. It is an environmentally benign method for the control of stored grain pests and has great development potential.

Therapeutic Evaluation of Vrikshamla (Garcinia Cambogia) in the Management of Sthaulya (Obesity) w.s.r Dyslipidemia - A Case Report

Human community is in agony of grave metabolic disorder i.e., obesity/Sthaulya roga. It is inclined to become miserable because of the attenuated Dosha in the body. Sedentary lifestyle, hampered sexual life, extreme lassitude, will be prone to engulf the normalcy of an individual, which ultimately leads to decreased life span. It is widely recognized that obesity has emerged as an epidemic in developed nations. It continues to be an issue of great concern. In addition, we now face the emergence of obesity as a worldwide phenomenon, affecting affluent and ordinary group of class. Here in this case report the objective is to find out the efficacy of Vrikshamla (Garcinia Cambogia) in the management of Sthaulya (Obesity). Materials: A 32 years old male patient K/C/O obesity since three year. Accustomed him with sedentary lifestyle which leads to an drastic gain in the weight. Through physical findings, BMI of a patient is 32.3 and by investigations the diagnosis led to Sthaulya as well as dyslipidemia. The study was assessed by both subjective and objective criteria. The treatment plan opted was Ayurveda internal medicine “Vrikshamla are best in the management of Sthaulya, selected as per criteria and examined by means of Roga and Rogi Pariksha methods. Administered Vrikshamla 2gm per day for 60 days and subjective as well as objective parameters were Assessed based on before and after treatment. Discussion: Difference in the values of subjective and objective parameters, illustrate all the clinical observations in respect of incidences of Nidana, Lakshana and percentage of relief in the subject. Conclusion: In the present research work undertaken, Vrikshamla an herbal formulation prove its efficacy against dyslipidaemia.

Rapamycin Supplementation: Effect on Longevity in Drosophila melanogaster

Target of rapamycin (TOR) regulates a number of cellular responses, including autophagy. The purpose of this study was to investigate the effect on life span of supplementation with rapamycin dissolved in either dimethylsulfoxide (DMSO) or ethanol, in male and female flies of three strains of Drosophila melanogaster: Oregon R, w1118, and y w. The hypothesis was that longevity would be decreased regardless of strain, sex or solvent, consistent with an unpublished prior study using y w males in this laboratory, or alternatively that it would be increased as in publications from other laboratories. Flies were exposed to food supplemented with 200 µM rapamycin dissolved in one of the two solvents before being mixed into a standard agar‐yeast‐cornmeal‐sucrose medium. Supplementation was continuous beginning 2 d posteclosion. The mean life span of Oregon R females was diminished by rapamycin in both ethanol and DMSO solvents, by 17% and 13%, respectively (P &lt; 0.0005). Oregon R males also exhibited a shortened mean life span, which was significant in DMSO (8%, P = 0.008) but not ethanol (3%, P = 0.9). In contrast, w1118 female flies had a 4% increase in mean life span with rapamycin dissolved in ethanol (P &lt; 0.0005) but not DMSO (1% increase, P = 0.2). Rapamycin decreased life span in w1118 males, but the effect was significant only in DMSO (22%, P = 0.002), not ethanol (10%, P = 0.6). It decreased longevity significantly in y wflies of both sexes on both solvents, by 9% in females and 7‐12% in males (all P &lt; 0.0005 except male/DMSO P = 0.04). Notably, the life spans of control flies differed significantly between the solvents, being longer with ethanol for y w of both sexes and longer with DMSO for Oregon R males and w1118 males. In conclusion, these results show that effects of rapamycin on life span of Drosophila are sex‐, strain‐ and solvent‐dependent.

Chromosome Segregation in the Oocyte: What Goes Wrong during Aging.

Human female fertility and reproductive lifespan decrease significantly with age, resulting in an extended post-reproductive period. The central dogma in human female reproduction contains two important aspects. One is the pool of oocytes in the human ovary (the ovarian reserve; approximately 106 at birth), which diminishes throughout life until menopause around the age of 50 (approximately 103 oocytes) in women. The second is the quality of oocytes, including the correctness of meiotic divisions, among other factors. Notably, the increased rate of sub- and infertility, aneuploidy, miscarriages, and birth defects are associated with advanced maternal age, especially in women above 35 years of age. This postponement is also relevant for human evolution; decades ago, the female aging-related fertility drop was not as important as it is today because women were having their children at a younger age. Spindle assembly is crucial for chromosome segregation during each cell division and oocyte maturation, making it an important event for euploidy. Consequently, aberrations in this segregation process, especially during the first meiotic division in human eggs, can lead to implantation failure or spontaneous abortion. Today, human reproductive medicine is also facing a high prevalence of aneuploidy, even in young females. However, the shift in the reproductive phase of humans and the strong increase in errors make the problem much more dramatic at later stages of the female reproductive phase. Aneuploidy in human eggs could be the result of the non-disjunction of entire chromosomes or sister chromatids during oocyte meiosis, but partial or segmental aneuploidies are also relevant. In this review, we intend to describe the relevance of the spindle apparatus during oocyte maturation for proper chromosome segregation in the context of maternal aging and the female reproductive lifespan.

Dietary cadmium induced declined locomotory and reproductive fitness with altered homeostasis of essential elements in Drosophila melanogaster

Cadmium (Cd) exerts detrimental effects on multiple biological processes of the living organisms along with epigenetic transgenerational effect. Drosophila melanogaster offers unique opportunity to evaluate Cd toxicity when studying important life traits in short duration of time by designing distinct behavioural assays. Present study utilized this model organism to assess Cd induced lethality, retarded growth, decreased life span and altered behaviour of the animals either at larval or adult stage. Our investigations revealed reduced locomotion and reproductive fitness of the animals upon Cd exposure. Transgenerational effect on locomotion was found to be behaviour specific as larval crawling was affected, but adult fly negative geotaxis was comparable to the control. Mechanistically, decreased antioxidant enzymes activity, superoxide dismutase (SOD) and catalase (CAT) together with altered homeostasis of essential elements (Fe, Zn and Mg) may be responsible for the observed effects. Altogether our work showed extensive range of Cd altered Drosophila behaviour which warrants need to control environmental Cd toxicity.

Disclosing the Antioxidant and Neuroprotective Activity of an Anthocyanin-Rich Extract from Sweet Cherry (Prunus avium L.) Using In Vitro and In Vivo Models.

In this study, an autochthonous variety of sweet cherry (Prunus avium L.), namely “Moretta di Vignola”, was processed to prepare extracts rich in polyphenols, which were characterized by high-performance liquid chromatography (HPLC) separation coupled to UV/DAD and ESI-MSn analysis. Then, a sweet cherry anthocyanin-rich extract (ACE) was prepared, fully characterized and tested for its activity against Parkinson’s disease (PD) in cellular (BV2 microglia and SH-SY5Y neuroblastoma) and in Drosophila melanogaster rotenone (ROT)-induced model. The extract was also evaluated for its antioxidant activity on Caenorhabditis elegans by assessing nematode resistance to thermal stress. In both cell lines, ACE reduced ROT-induced cell death and it decreased, alone, cellular reactive oxygen species (ROS) content while reinstating control-like ROS values after ROT-induced ROS rise, albeit at different concentrations of both compounds. Moreover, ACE mitigated SH-SY5Y cell cytotoxicity in a non-contact co-culture assay with cell-free supernatants from ROT-treated BV-2 cells. ACE, at 50 µg/mL, ameliorated ROT (250 μM)-provoked spontaneous (24 h duration) and induced (after 3 and 7 days) locomotor activity impairment in D. melanogaster and it also increased survival and counteracted the decrease in fly lifespan registered after exposure to the ROT. Moreover, heads from flies treated with ACE showed a non-significant decrease in ROS levels, while those exposed to ROT markedly increased ROS levels if compared to controls. ACE + ROT significantly placed the ROS content to intermediate values between those of controls and ROT alone. Finally, ACE at 25 µg/mL produced a significant increase in the survival rate of nematodes submitted to thermal stress (35 °C, 6–8 h), at the 2nd and 9th day of adulthood. All in all, ACE from Moretta cherries can be an attractive candidate to formulate a nutraceutical product to be used for the prevention of oxidative stress-induced disorders and related neurodegenerative diseases.

Evaluation of lifespan promoting effects of biofortified wheat in Drosophila melanogaster.

Evaluation of nutritionally enhanced biofortified dietary interventions that increase lifespan may uncover cost-effective and sustainable approaches for treatment of age-related morbidities and increasing healthy life expectancy. In this study, we report that anthocyanin rich, high yielding crossbred blue wheat prolongs lifespan of Drosophila melanogaster in different dietary contexts. In addition to functioning as an antioxidant rich intervention, the biofortified blue wheat also works through modulating expression of DR pathway genes including AMPK alpha, SREBP, PEPCK and Cry. Supplementation with blue- or purple-colored wheat provided better protection against paraquat-induced oxidative stress than control diet and increased survivability of flies in which superoxide dismutase 2 was knocked down conditionally in adults. Lastly, our findings indicate that supplementing biofortified blue wheat formulated diet prevented the decrease in lifespan and cardiac structural pathologies associated with intake of high fat diet. Overall, our findings indicate that plant-based diets formulated with biofortified cereal crops promote healthy ageing and delay progression of diseases that are exacerbated by accumulation of oxidative damage.

AN AYURVEDIC MANAGEMENT OF SPINAL MUSCULAR ATROPHY (SMA) – A CASE STUDY

Spinal Muscular Atrophy (SMA) is the second leading genetic disorder inherited in the autosomal recessive pattern due to the absence of the SMN1 gene characterized by loss of motor neurons and progressive muscle wasting, often leading to dependent life and decreased life span. In Ayurveda, this condition can be considered as Kulaja Vyadhi wherein the patient’s Mamsa and Snayu is affected by Vata. This can be regarded as Mamsa-Snayugata Sarvanga Vata. It is said that Prakruta Vata dosha is the life, it is the strength, it is the sustainer of the body, it holds the body and life together. If it is Vikruta it produces Sankocha, Khanja, Kubjatva, Pangutva, Khalli and Soshana of Anga. So, in this disease aggravated Vata does the vitiation of Mamsa and Snayu thus leading to Soshana of both, resulting in Stambha, Nischalikarana of Avayava. A 21years female patient was admitted to our I.P.D with c/o of reduced strength in all four limbs leading to the inability to walk and to maintain erect posture during standing and sitting positions. Based on Ayurvedic principles the patient was initially subjected to Avaranahara Chikitsa followed by Brimhana line of management. Keywords: Mamsagata vata, Snayugata vata, Sarvanga vata, Spinal muscular atrophy (SMA)

P.090 Evaluation of Mutant Alleles of Engrailed and Invected in Drosophila Melanogaster Models of Parkinson Disease

Background: Parkinson Disease (PD) is a neurodegenerative disorder, resulting in a gradual decline in voluntary movement, where lifespan remains stable. Drosophila melanogaster offer comparable gene sequences to those targeted in PD; among them are two transcription factors, engrailed (en) and invected (inv). Methods: Wild-type homozygous allele Oregon-R(en+, inv+) was compared to heterozygous mutants of en1, en4, en7, en54, en58, invW, inv30, and Df (2R) enEinvE. Nine climbing and aging studies were executed from crosses with w1118(en+, inv+) as the maternal genotype. Results: Independent-samples t-tests were conducted to compare the percent survival (in days). No significant differences were observed between the experimental groups and the control group. A mixed Analysis of Variance was conducted to compare climbing behaviour over time (in weeks) for all nine groups. Both main effects (group, time), and the interaction (group x time) were significant. Post hoc Fisher’s Least Significant Difference tests revealed a significant difference between the control group and en1, en4, en54, invW, and Df (2R) enEinvE groups. Conclusions: These results support the hypothesis that mutations of en, inv, or both will result in a PD phenotype and consequent decreased motor function of D. melanogaster PD models, with or without a significant decrease in lifespan.

Reevaluation of the effect of dietary restriction on different recombinant inbred lines of male and female mice.

Dietary restriction (DR) was reported to either have no effect or reduce the lifespan of the majority of the 41‐recombinant inbred (RI) lines studied by Liao et al. (Aging Cell, 2010, 9, 92). In an appropriately power longevity study (n > 30 mice/group), we measured the lifespan of the four RI lines (115‐RI, 97‐RI, 98‐RI, and 107‐RI) that were reported to have the greatest decrease in lifespan when fed 40% DR. DR increased the median lifespan of female RI‐115, 97‐RI, and 107‐RI mice and male 115‐RI mice. DR had little effect (<4%) on the median lifespan of female and male 98‐RI mice and male 97‐RI mice and reduced the lifespan of male 107‐RI mice over 20%. While our study was unable to replicate the effect of DR on the lifespan of the RI mice (except male 107‐RI mice) reported by Liao et al. (Aging Cell, 2010, 9, 92), we found that the genotype of a mouse had a major impact on the effect of DR on lifespan, with the effect of DR ranging from a 50% increase to a 22% decrease in median lifespan. No correlation was observed between the changes in either body composition or glucose tolerance induced by DR and the changes observed in lifespan of the four RI lines of male and female mice. These four RI lines of mice give the research community a unique resource where investigators for the first time can study the anti‐aging mechanism of DR by comparing mice in which DR increases lifespan to mice where DR has either no effect or reduces lifespan.

EIF2A-knockout mice reveal decreased life span and metabolic syndrome.

Eukaryotic initiation factor 2A (eIF2A) is a 65 kDa protein that functions in minor initiation pathways, which affect the translation of only a subset of messenger ribonucleic acid (mRNAs), such as internal ribosome entry site (IRES)‐containing mRNAs and/or mRNAs harboring upstream near cognate/non‐AUG start codons. These non‐canonical initiation events are important for regulation of protein synthesis during cellular development and/or the integrated stress response. Selective eIF2A knockdown in cellular systems significantly inhibits translation of such mRNAs, which rely on alternative initiation mechanisms for their translation. However, there exists a gap in our understanding of how eIF2A functions in mammalian systems in vivo (on the organismal level) and ex vivo (in cells). Here, using an eIF2A‐knockout (KO) mouse model, we present evidence implicating eIF2A in the biology of aging, metabolic syndrome and central tolerance. We discovered that eIF2A‐KO mice have reduced life span and that eIF2A plays an important role in maintenance of lipid homeostasis, the control of glucose tolerance, insulin resistance and also reduces the abundance of B lymphocytes and dendritic cells in the thymic medulla of mice. We also show the eIF2A KO affects male and female mice differently, suggesting that eIF2A may affect sex‐specific pathways. Interestingly, our experiments involving pharmacological induction of endoplasmic reticulum (ER) stress with tunicamycin did not reveal any substantial difference between the response to ER stress in eIF2A‐KO and wild‐type mice. The identification of eIF2A function in the development of metabolic syndrome bears promise for the further identification of specific eIF2A targets responsible for these changes.

Age-specific mortality and fecundity of a spider mite under diet restriction and delayed mating.

Numerous experimental life-history studies on aging are mainly baised on two classical models-fruit fly Drosophila melanogaster (Meigen) and nematode Caenorhabditis elegans (Maupas)-with relatively little attention given to other organisms with different life-history characters. Two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) differs from many other arthropods in that the females continue their growth in the early adult stage and can reproduce sexually and asexually. In this study, the influences of dietary restriction and delayed mating on the aging patterns of the spider mite were examined with the prevailing survival and reproduction trade-off hypothesis of aging being tested. Significant sex-specific responses of the spider mites were found. The females showed longevity extension on diet restriction (fasting for 2days in every 4days) compared with their counterparts being fed ad libitum, and after delayed mating for 9days, while the males displayed a decrease in lifespan when experiencing diet restriction but were not significantly influenced by delayed mating. Path analysis was used to investigate the relationship between mite survival and reproduction traits, including longevity, female lifetime reproduction, age at first reproduction, early reproductive efforts and late reproductive efforts, yielding no evidence for trade-offs between these life-history traits. The additive effects of dietary restriction and delayed mating in lifespan extension of female spider mites were confirmed, proving that diet restriction is a robust anti-aging intervention, and that later onset of reproduction can prolong adult lifespan in females.

Inbreeding effects in Drosophila congenic strains: the influence of genetic background of different origin

Aim. To compare reproductive indices and stress resistance of Drosophila at outbreeding and inbreeding. Methods. Drosophila melanogaster congenic strains with incomplete development of the radial wing vein – radius incompletus – were used: the laboratory one and the strain, in which the mutation was placed into the genetic background of wild type strain, which originates from the natural population from radiation contaminated territory. Before the experiment strains have passed 65 generations of inbreeding. Viability (number of individuals, pupa stage mortality), dominant lethal mutations frequency and life span of imago at starvation were analysed. Results. After inbreeding, there was a decrease in the frequency of dominant lethal mutations and an increase in viability of the strain, which originates from the natural population, and a decrease of mortality at the pupal stage in both strains. Decreased life span of imago at starvation has been shown only for the inbred strain, which originates from the natural population. Conclusions. Inbreeding for 65 generations has no significant negative effect on reproductive indices; reduction of stress resistance during inbreeding has been shown only for the strain, which originates from the radiation contaminated territory. &#x0D; Keywords: Drosophila, viability, dominant lethal mutations, life span of imago at starvation, inbreeding.