Wild-type Canton-S Flies Research Articles

Melatonin Increases Life Span, Restores the Locomotor Activity, and Reduces Lipid Peroxidation (LPO) in Transgenic Knockdown Parkin Drosophila melanogaster Exposed to Paraquat or Paraquat/Iron.

Parkinson's disease (PD) is a complex progressive neurodegenerative disorder involving impairment of bodily movement caused by the specific destruction of dopaminergic (DAergic) neurons. Mounting evidence suggests that PD might be triggered by an interplay between environmental neurotoxicants (e.g., paraquat, PQ), heavy metals (e.g., iron), and gene alterations (e.g., PARKIN gene). Unfortunately, there are no therapies currently available that protect, slow, delay, or prevent the progression of PD. Melatonin (Mel, N-acetyl-5-methoxy tryptamine) is a natural hormone with pleiotropic functions including receptor-independent pathways which might be useful in the treatment of PD. Therefore, as a chemical molecule, it has been shown that Mel prolonged the lifespan and locomotor activity, and reduced lipid peroxidation (LPO) in wild-type Canton-S flies exposed to PQ, suggesting antioxidant and neuroprotective properties. However, it is not yet known whether Mel can protect or prevent the genetic model parkin deficient in flies against oxidative stress (OS) stimuli. Here, we show that Mel (0.5, 1, 3mM) significantly extends the life span and locomotor activity of TH > parkin-RNAi/ + Drosophila melanogaster flies (> 15days) compared to untreated flies. Knock-down (K-D) parkin flies treated with PQ (1mM) or PQ (1mM)/iron (1mM) significantly diminished the survival index and climbing abilities (e.g., 50% of flies were dead and locomotor impairment by days 4 and 3, respectively). Remarkably, Mel reverted the noxious effect of PQ or PQ/iron combination in K-D parkin. Indeed, Mel protects TH > parkin-RNAi/ + Drosophila melanogaster flies against PQ- or PQ/iron-induced diminish survival, locomotor impairment, and LPO (e.g., 50% of flies were death and locomotor impairment by days 6 and 9, respectively). Similarly, Mel prevented K-D parkin flies against both PQ and PQ/iron. Taken together, these findings suggest that Mel can be safely used as an antioxidant and neuroprotectant agent against OS-stimuli in selective individuals at risk to suffer early-onset Parkinsonism and PD.

Mating experience modifies locomotor performance and promotes episodic motor activity in Drosophila melanogaster

Sexual behavior is a routine among animal species. Sexual experience has several behavioral consequences in insects, but its physiological basis is less well-understood. The episodic motor activity with a periodicity around 19 s was unintentionally observed in the wildtype Canton-S flies and was greatly reduced in the white-eyed mutant w1118 flies. Episodic motor activity co-exists with several consistent locomotor performances in Canton-S flies whereas reduced episodic motor activity is accompanied by neural or behavioral abnormalities in w1118 flies. The improvements of both episodic motor activity and locomotor performance are co-inducible by a pulsed light illumination in w1118. Here we show that mating experience of w1118 males promoted fast and consistent locomotor activities and increased the power of episodic motor activities. Compared with virgin males, mated ones showed significant increases of boundary preference, travel distance over 60 s, and increased path increments per 0.2 s. In contrast, mated males of Canton-S showed decreased boundary preference, increased travel distance over 60 s, and increased path increments per 0.2 s. Additionally, mated males of w1118 displayed increased power amplitude of periodic motor activities at 0.03-0.1 Hz. These data indicated that mating experience promoted fast and consistent locomotion and improved episodic motor activities in w1118 male flies.

Ellagic acid prolongs the lifespan of Drosophila melanogaster.

Wild-type Canton-S flies of Drosophila melanogaster were treated with ellagic acid at 100μM and 200μM concentrations. Longevity assay showed male flies fed with 200 μM ellagic acid displayed longer mean lifespan and maximum lifespan than control flies. Female flies fed with 200 μM ellagic acid laid less number of eggs than control. The eclosion time was less in female flies fed with 200 μM ellagic acid. Ellagic acidfed female flies performed better than male flies and control flies for heat shock tolerance and starvation stress. Male flies treated with 100 μM ellagic acid recovered faster from cold shock compared with control flies. Male and female flies treated with ellagic acid displayed increased survival following exposure to 5% hydrogen peroxide. Gene expression studies displayed upregulated expressions of CAT, dFOXO, ATG1, and SOD2 in ellagic acid-treated male flies, and upregulated expressions of dFOXO, CAT, and SOD2 in ellagic acid-treated female flies. Results from these studies show the pro-longevity effect of ellagic acid on Drosophila melanogaster.

The role of DNA repair genes in radiation-induced adaptive response in Drosophila melanogaster is differential and conditional.

Studies in human and mammalian cell cultures have shown that induction of DNA repair mechanisms is required for the formation of stimulation effects of low doses of ionizing radiation, named "hormesis". Nevertheless, the role of cellular defense mechanisms in the formation of radiation-induced hormesis at the level of whole organism remains poorly studied. The aim of this work was to investigate the role of genes involved in different mechanisms and stages of DNA repair in radioadaptive response and radiation hormesis by lifespan parameters in Drosophila melanogaster. We studied genes that control DNA damage sensing (D-Gadd45, Hus1, mnk), nucleotide excision repair (mei-9, mus210, Mus209), base excision repair (Rrp1), DNA double-stranded break repair by homologous recombination (Brca2, spn-B, okr) and non-homologous end joining (Ku80, WRNexo), and the Mus309 gene that participates in several mechanisms of DNA repair. The obtained results demonstrate that in flies with mutations in studied genes radioadaptive response and radiation hormesis are absent or appear to a lesser extent than in wild-type Canton-S flies. Chronic exposure of γ-radiation in a low dose during pre-imaginal stages of development leads to an increase in expression of the studied DNA repair genes, which is maintained throughout the lifespan of flies. However, the activation of conditional ubiquitous overexpression of DNA repair genes does not induce resistance to an acute exposure to γ-radiation and reinforces its negative impact.

Epigallocatechin-3-Gallate Protects and Prevents Paraquat-Induced Oxidative Stress and Neurodegeneration in Knockdown dj-1-β Drosophila melanogaster.

Epigallocatechin-3-gallate (EGCG) is a polyhydroxyphenol constituent of green tea (e.g., Camellia sinensis) with known antioxidant properties. Due to these properties, others have proposed it as a potential therapeutic agent for the treatment of Parkinson's disease (PD). Previously, we demonstrated that EGCG prolonged the lifespan and locomotor activity in wild-type Canton-S flies exposed to the neurotoxicant paraquat (PQ), suggesting neuroprotective properties. Both gene mutations and environmental neurotoxicants (e.g., PQ) are factors involved in the development of PD. Thus, the first aim of this study was to create a suitable animal model of PD, which encompasses both of these factors. To create the model, we knocked down dj-1-β function specifically in the dopaminergic neurons to generate TH > dj-1-β-RNAi/+ Drosophila melanogaster flies. Next, we induced neurotoxicity in the transgenic flies with PQ. The second aim of this study was to validate the model by comparing the effects of vehicle, EGCG, and chemicals with known antioxidant and neuroprotective properties in vivo (e.g., propyl gallate and minocycline) on life-span, locomotor activity, lipid peroxidation, and neurodegeneration. The EGCG treatment provided protection and prevention from the PQ-induced reduction in the life-span and locomotor activity and from the PQ-induced increase in lipid peroxidation and neurodegeneration. These effects were augmented in the EGCG-treated flies when compared to the flies treated with either PG or MC. Altogether, these results suggest that the transgenic TH > dj-1-β-RNAi/+ flies treated with PQ serve as a suitable PD model for screening of potential therapeutic agents.

The white gene controls copulation success in Drosophila melanogaster

Characteristics of male courtship behavior in Drosophila melanogaster have been well-described, but the genetic basis of male-female copulation is largely unknown. Here we show that the white (w) gene, a classical gene for eye color, is associated with copulation success. 82.5% of wild-type Canton-S flies copulated within 60 minutes in circular arenas, whereas few white-eyed mutants mated successfully. The w+ allele exchanged to the X chromosome or duplicated to the Y chromosome in the white-eyed genetic background rescued the defect of copulation success. The w+-associated copulation success was independent of eye color phenotype. Addition of the mini-white (mw+) gene to the white-eyed mutant rescued the defect of copulation success in a manner that was mw+ copy number-dependent. Lastly, male-female sexual experience mimicked the effects of w+/mw+ in improving successful copulation. These data suggest that the w+ gene controls copulation success in Drosophila melanogaster.

Hypnotic effects of a novel anti-insomnia formula on Drosophila insomnia model.

To assess the biological effects of the six-herb mixture Anti-Insomia Formula (AIF) extract using caffeine-induced insomnia Drosophila model and short-sleep mutants. Caffeineinduced insomnia wild-type Drosophila and short-sleep mutant flies minisleep (mns) and Hyperkinetic(Y) (Hk(Y)) were used to assess the hypnotic effects of the AIF in vivo. The night time activity, the amount of night time sleep and the number of sleep bouts were determined using Drosophila activity monitoring system. Sleep was defined as any period of uninterrupted behavioral immobility (0 count per minute) lasting > 5 min. Night time sleep was calculated by summing up the sleep time in the dark period. Number of sleep bouts was calculated by counting the number of sleep episodes in the dark period. AIF at the dosage of 50 mg/mL, effectively attenuated caffeine-induced wakefulness (P<0.01) in wild-type Canton-S flies as indicated by the reduction of the sleep bouts, night time activities and increase of the amount of night time sleep. AIF also significantly reduced sleeping time of short-sleep Hk(Y) mutant flies (P<0.01). However, AIF did not produce similar effect in mns mutants. AIF might be able to rescue the abnormal condition caused by mutated modulatory subunit of the tetrameric potassium channel, but not rescuing the abnormal nerve firing caused by Shaker gene mutation. This study provides the scientific evidence to support the use of AIF in Chinese medicine for promoting sleep quality in insomnia.

Circadian expression of the presynaptic active zone protein bruchpilot in the lamina of Drosophila melanogaster

In the fly's visual system, the morphology of cells and the number of synapses change during the day. In the present study we show that in the first optic neuropil (lamina) of Drosophila melanogaster, a presynaptic active zone protein Bruchpilot (BRP) exhibits a circadian rhythm in abundance. In day/night (or light/dark, LD) conditions the level of BRP increases two times, in the morning and in the evening. The same pattern of changes in the BRP level was detected in whole brain homogenates, thus indicating that the majority of synapses in the brain peaks twice during the day. However, these two peaks in BRP abundance, measured as the fluorescence intensity of immunolabeling, seem to be regulated differently. The peak in the morning is predominantly regulated by light and involves the transduction pathway in the retina photoreceptors. This peak is present neither in wild-type Canton-S flies in constant darkness (DD), nor in norpA(7) phototransduction mutant in LD. However, it also depends on the clock gene per, because it is abolished in the per(0) arrhythmic mutant. In turn, the peak of BRP in the evening is endogenously regulated by an input from the pacemaker located in the brain. This peak is present in Canton-S flies in DD, as well as in the norpA(7) mutant in LD, but is absent in per(01), tim,(01) and cry(01) mutants in LD. In addition both peaks seem to depend on clock gene-expressing photoreceptors and glial cells of the visual system.

Remembering Nutrient Quality of Sugar in Drosophila

Taste is an early stage in food and drink selection for most animals [1, 2]. Detecting sweetness indicates the presence of sugar and possible caloric content. However, sweet taste can be an unreliable predictor of nutrient value because some sugars cannot be metabolized. In addition, discrete sugars are detected by the same sensory neurons in the mammalian [3] and insect [4, 5] gustatory systems, making it difficult for animals to readily distinguish the identity of different sugars using taste alone [6-8]. Here we used an appetitive memory assay in Drosophila [9-11] to investigate the contribution of palatability and relative nutritional value of sugars to memory formation. We show that palatability and nutrient value both contribute to reinforcement of appetitive memory. Nonnutritious sugars formed less robust memory that could be augmented by supplementing with a tasteless but nutritious substance. Nutrient information is conveyed to the brain within minutes of training, when it can be used to guide expression of a sugar-preference memory. Therefore, flies can rapidly learn to discriminate between sugars using a postingestive reward evaluation system, and they preferentially remember nutritious sugars.

Sleep Deprivation Specifically Impairs Short-term Olfactory Memory in Drosophila

Sleep is crucial to memory consolidation in humans and other animals; however, the effect of insufficient sleep on subsequent learning and memory remains largely elusive. Learning and memory after 1-day sleep deprivation (slpD) was evaluated using Pavlovian olfactory conditioning in Drosophila, and locomotor activity was measured using the Drosophila Activity Monitoring System in a 12:12 light-dark cycle. We found that slpD specifically impaired 1-h memory in wild type Canton-S flies, and this effect could persist for at least 2 h. However, alternative stresses (heat stress, oxidative stress, starvation, and rotation stress) did not result in a similar effect and left the flies' memory intact. Mechanistic studies demonstrated that flies with either silenced transmission of the mushroom body (MB) during slpD or down-regulated cAMP levels in the MB demonstrated no slpD-induced 1-h memory impairment. We found that slpD specifically impaired 1-h memory in Drosophila, and either silencing of MB transmission during slpD or down-regulation of the cAMP level in the MB protected the flies from slpD-induced impairment.

Response of Drosophila to Wasabi Is Mediated by painless, the Fly Homolog of Mammalian TRPA1/ANKTM1

A number of repellent compounds produced by plants elicit a spicy or pungent sensation in mammals . In several cases, this has been found to occur through activation of ion channels in the transient receptor potential (TRP) family . We report that isothiocyanate (ITC), the pungent ingredient of wasabi, is a repellent to the insect Drosophila melanogaster, and that the painless gene, previously known to be required for larval nociception, is required for this avoidance behavior. A painless reporter gene is expressed in gustatory receptor neurons of the labial palpus, tarsus, and wing anterior margin, but not in olfactory receptor neurons, suggesting a gustatory role. Indeed, painless expression overlaps with a variety of gustatory-receptor gene reporters. Some, such as Gr66a, are known to be expressed in neurons that mediate gustatory repulsion . painless mutants are not taste blind; they show normal aversive gustatory behavior with salt and quinine and attractive responses to sugars and capsaicin. The painless gene is an evolutionary homolog of the mammalian "wasabi receptor" TRPA1/ANKTM1 , also thought to be involved in nociception. Our results suggest that the stinging sensation of isothiocyanate is caused by activation of an evolutionarily conserved molecular pathway that is also used for nociception.

Sleep homeostasis in Drosophila melanogaster.

The fruit fly Drosophila melanogaster is emerging as a promising model system for the genetic dissection of sleep. As in mammals, sleep in the fruit fly is a reversible state of reduced responsiveness to the external world and has been defined using an array of behavioral, pharmacologic, molecular, and electrophysiologic criteria. A central feature of mammalian sleep is its homeostatic regulation by the amount of previous wakefulness. Dissecting the mechanisms of homeostatic regulation is likely to provide key insights into the functions of sleep. Thus, it is important to establish to what extent sleep homeostasis is similar between mammals and flies. This study was designed to determine whether in flies, as in mammals, (1) sleep rebound is dependent on prior time awake; (2) sleep deprivation affects the intensity, in addition to the duration, of sleep rebound; (3) sleep loss impairs vigilance and performance; (4) the sleep homeostatic response is conserved among different wild-type lines, and between female and male flies of the same line. Motor activity of individual flies was recorded at 1-minute intervals using the infrared Drosophila Activity Monitoring System during 2 baseline days; during 6, 12, and 24 hours of sleep deprivation; and during 2 days of recovery. Sleep was defined as any period of uninterrupted behavioral immobility lasting > 5 minutes. Sleep continuity was measured by calculating the number of brief awakenings, the number and duration of sleep episodes, and a sleep continuity score. Vigilance before and after sleep deprivation was assessed by measuring the escape response triggered by 2 different aversive stimuli. Fly sleep research laboratory at UW-Madison. Adult flies of the Canton-S (CS) strain and 116 other wild-type lines (> or = 16 female and > or = 16 male flies per line). In wild-type CS flies, as in mammals, the amount of sleep recovered after sleep deprivation was dependent on prior time awake. Relative to baseline sleep, recovery sleep in CS flies was less fragmented, with longer sleep episodes, and was associated with a higher arousal threshold. Sleep deprivation in CS flies also reduced performance. Sleep duration and continuity increased after 24 hour of sleep deprivation in all the other wild-type lines tested. The sleep homeostatic response in fruit flies is a stable phenotype and shares most of, if not all, the major features of mammalian sleep homeostasis, thus supporting the use of Drosophila as a model system for the genetic dissection of sleep mechanisms and functions.

Dissociation of visual associative and motor learning in Drosophila at the flight simulator.

Ever since operant conditioning was studied experimentally, the relationship between associative learning and possible motor learning has become controversial. Although motor learning and its underlying neural substrates have been extensively studied in mammals, it is still poorly understood in invertebrates. The visual discriminative avoidance paradigm of Drosophila at the flight simulator has been widely used to study the flies' visual associative learning and related functions, but it has not been used to study the motor learning process. In this study, newly-designed data analysis was employed to examine the flies' solitary behavioural variable that was recorded at the flight simulator-yaw torque. Analysis was conducted to explore torque distributions of both wild-type and mutant flies in conditioning, with the following results: (1) Wild-type Canton-S flies had motor learning performance in conditioning, which was proved by modifications of the animal's behavioural mode in conditioning. (2) Repetition of training improved the motor learning performance of wild-type Canton-S flies. (3) Although mutant dunce(1) flies were defective in visual associative learning, they showed essentially normal motor learning performance in terms of yaw torque distribution in conditioning. Finally, we tentatively proposed that both visual associative learning and motor learning were involved in the visual operant conditioning of Drosophila at the flight simulator, that the two learning forms could be dissociated and they might have different neural bases.

Influence of food on frequency-dependent sexual activity ofDrosophila Melanogaster

When two types of Drosophila are in competition, the frequency dependence of mating successes frequently is measured by direct observation of copulating pairs in "Elens-Wattiaux" observation chambers, the relative frequency of both types being varied. The present experiments, concerning white-ebony mutants in competition with wild-type Canton-S flies, show that the presence of food in the mating chamber influences the sexual activity of flies, this influence differing in the two types when food is present. Thus, in order to have a realistic estimation of frequency dependence, it would seem prudent to conduct these experiments with food in the chamber. Three methods are used to analyze observation data: K coefficients of Petit and Ehrman, regression equations of Ayala and Campbell, and regression equations of Wattiaux and Lichtenberger. These three methods are compared and discussed.

Regulation of phosphorylase kinase in Drosophila melanogaster

The regulation of phosphorylase kinase has been studied in crude homogenates of adult flies and larval brains of Drosophila melanogaster. The kinase has an alkaline pH optimum (about pH 8.6), is inhibited by an excess of Mg 2+ and is stimulated by Ca 2+ in the homogenates. Incubation of larval brains with octopamine, especially in the presence of theophylline, or with forskolin, markedly elevated the level of cAMP with no, or marginal, activation of phosphorylase. In contrast, Ca 2+ in the presence of A-23187 caused a two-fold increase in phosphorylase a. The mutant dunce M11 flies contain six to seven times as much cAMP as the wild type Canton-S flies and have a somewhat elevated phosphorylase a level.