Essential oils from 22 plant species were tested for their insecticidal activities against spotted wing drosophila (SWD), Drosophila suzukii Matsumura, using fumigation and contact bioassay. Responses varied with the essential oils, their constituents and concentrations. Strong fumigation activities were observed from the essential oils of wintergreen (Gaultheria fragrantissima), croton (Croton anisatum) and star anise (Illicium verum). Strong contact activities were observed in the essential oils of oriental sweetgum (Liquidambar orientalis), cassia (Cinnamomum cassia), damask rose (Rosa damascena) and sandalwood (Santalum album). The compositions of these selected essential oils were identified using gas chromatographymass spectrophotometer. The compounds identified were tested individually for their insecticidal activities against SWD. Responses varied by doses for each compound. The results showed that natural materials are as effective as synthetic pesticides.

Spotted wing drosophila, Drosophila suzukii, native to eastern and southeastern Asia, has become one of the most harmful pests causing serious damage to fruits such as blueberry, cherry, and others in Northern America and Europe. For quarantine sanitary purpose, methyl bromide (MeBr) has been used for a long time. However, it is under regulation because of its adverse effect of ozone layer depletion. Thus, alternative strategies to MeBr are needed to meet the quarantine requirement. In this study, we investigated effects of gamma ray irradiation (0, 50, 100, 200 and 300 Gy) on the development and reproduction of D. suzukii to offer a guideline in using gamma ray for dis-infestation of this pest. The higher doses of gamma ray caused more adverse effects on development and hatchability of D. suzukii. Development and oviposition of D. suzukii was significantly depressed at above certain doses, respective to each developmental stage. When eggs were treated with the doses of gamma ray, eggs hatched in some ratios at all doses. Even though some larvae developed to pupae under 100 Gy irradiation, all these pupae did not emerge to adults at all doses. When larvae were treated with gamma ray, some of them pupated at each doses. However these pupae did not emerge to adults at all under all doses. When pupae were irradiated, the emerged adults did not oviposit eggs above 100 Gy. When adults were irradiated, oviposition occurred normally, but fecundity and hatchability of the eggs were reciprocal to the doses.

Internal sperm storage after mating is important for insect reproduction, because it permits delayed fertilisation, and post-copulatory mate choice in polyandrous females. The polyandry is common in many animal taxa including insects, because it increases female fitness by reducing the risk of infertility and providing opportunities for sperm competition and choice. The reproductive success of males, on the other hand, often depends upon avoidance of sperm competition by preventing mated females from copulating and receiving sperm from other male suitors. A widespread strategy used by males is the use of the male seminal fluid proteins (SFPs) that form the mating plug and alter female behaviors, for example by suppressing mating receptivity and elevating egg-laying. Under these circumstances, females are expected to evolve mechanism(s) to control exposure to the male SFPs in order to maximize fitness by balancing the positive and negative impacts of polyandry. Here, we discover that Drosophila melanogaster females eject male ejaculates 1-6 h after mating with a stereotypic behaviour, and that this is regulated by a brain neuropeptide pathway composed of diuretic hormone 44 (Dh44), and its receptor Dh44R1. We showed that suppressing Dh44 or Dh44R1 signals in the brain expedites sperm ejection, whereas enhancing Dh44 or Dh44R1 signals delays sperm ejection. This study uncovers a molecular mechanism by which females can influence sperm competition and selection, and counter actively the negative impact of polyandry.

The spotted-wing drosophila (SWD), Drosophila suzukii (Diptera: Drosophilidae), was originally observed in a few Asian countries, but is now found even in North America and Europe. Genetic information on geographic variation and relationship may broaden our understanding of origin and migration. As a first step, in this study, a portion of mitochondrial COI gene was sequenced to understand genetic relationship and diversity in Korea. Sequencing of 104 individuals provided 57 haplotypes, with the maximum sequence divergence of 1.5%, suggesting high haplotype diversity and moderate sequence divergence. Comparison to GenBankregistered D. suzukii haplotypes (possibly from Spain, Portugal, USA) has shown 100% sequence identity to most of the haplotypes found in this study, but two USA sequences were found to be independent haplotypes, with the sequence divergence ranging from 0.5% ~ 1.4% from our samples in the 553-bp comparison. Phylogenetically, no separable group was found, but, population genetically, the only Chinese population, Sandong, was significantly differentiated (p < 0.05) from all Korean populations, without sharing any haplotype. Among 28 pairwise comparisons of Korean populations only two comparisons showed a significant genetic differentiation, indicating that no population in Korea is completely isolated. Geographically, one haplotype (SWDBA06) was relatively widespread (five among nine localities) and a few haplotypes were found in more than one locality, but most haplotypes were restricted in a locality as a single individual. Overall, high rate of per generation female migration (Nm = 0.75 ~ infinite) and low level of geographic separation (FST=0~0.40) among localities were characteristic. Current data is limited mainly to Korean localities, thus, an expanded study may provide further scrutinized analysis for the fly.

Mating elicits a dramatic changes in physiology, behavior, and life-history traits in insects, but little is known about the relationship between mating and the capacity of insects to resist environmental stressors. Starvation is one of the most ubiquitous forms of environmental stress faced by all insects under natural conditions. Previous studies using Drosophila melanogaster flies has shown that mated females lived longer under starvation than did virgin females, but the mechanistic basis for such post-mating increase in starvation resistance remains largely unexplored. The objective of this study was to investigate the behavioral and physiological mechanisms of mating-induced alteration in starvation resistance and its heritable genetic variations in D. melanogaster. In the first experiment (Experiment 1), we compared starvation resistance (measured as starving time before death), body compositions, and food intake between mated and unmated flies of both sexes using a large outbred population. In the second experiment (Experiment 2), starvation resistance and body composition were quantified for mated male and female flies derived from each of 19 highly inbred genetic lines. Results from Experiment 1 showed that mated females were better able to resist starvation than virgin females and males because they ate more and thus laid down more fats in their body. Results from Experiment 2 revealed a significant heritable genetic variation in starvation resistance and its correlated body composition parameters for both sexes. Overall, females had a higher starvation resistance than males, but the magnitude of such intersexual difference varied among genetic lines, as suggested by a significant sex-by-line interaction. Cross-sex genetic correlations were highly significant and positive for starvation resistance, indicating that the genetic factors controlling the starvation resistance in D. melanogaster are shared between the two sexes.

Starvation resistance is an important fitness trait that is controlled by both environmental and heritable factors. The main objective of this study is to explore the genotype-by-nutrient interactions for starvation resistance and its correlating physiological traits in Drosophila melanogaster. In this study, we conducted a split-family quantitative genetic experiment, in which female adults of Drosophila from 19 isofemale genetic lines were allowed to ingest one of two synthetic diets that differed in protein-to-carbohydrate ratio (P:C = 4:1 or 1:16 with the P+C concentration of 120 g L-1) before they were assayed for starvation time and lipid storage. In all genetic lines, Drosophila flies that had fed carbohydrate-rich diet (P:C=1:16) resisted starvation better and stored more lipids than did those that had fed protein-rich diet (4:1). Importantly, the extent to which both starvation resistance and lipid reserves were affected by dietary P:C ratio varied greatly among different genetic lines of Drosophila, as indicated by significant genotypeby-nutrient interactions for these two traits. When the patterns of the bivariate reaction norm for body lipid and starvation resistance were compared across the genotypes, we found strong evidence for genetic variations in the pattern of energy storage and usage associated with maintaining survival under starvation in Drosophila.

Early onset torsion dystonia is caused by mutations in DYT1 gene in humans. Two deletion mutations and one missense mutation were found from patients with this devastating disorder. The molecular and cellular etiology underlying this disorder is not still understood yet. Because vertebrates have more than 4 homologs in their genomes, it is very hard to elucidate the exact in vivo functions of Torsin1A. Instead, Drosophila has only one homolog named Torsin. To investigate the in vivo functions of Torsin, we generated and characterized transgenic flies expressing coding regions of Torsin mRNA or double stranded inhibitory DNA constructs (RNAi). The specific antibodies for Drosophila Torsin (DTor) also were generated. The transgenic expression of DTor cDNA or RNAi in all tissue induced significant changes in DTor proteins levels. Even though expression of DTor cDNA in neuronal system increased the amount of DTor proteins, expression of DTor RNAi did not significantly altered the amount of DTor. Consistent with this result, the numbers of flies with motor-activity were not discernible among neuronal expression lines. However, flies expressing DTor cDNA or RNAi on muscles showed significantly altered locomotor ability, suggesting that DTor plays important roles in regulating motor-activity at the post-synaptic terminals of motor neurons. In addition, DTor over-expressing flies showed increased resistance to H2O2. In the future study, we will found how those phenotypes were accomplished by performing various experiments. (NRF-2012R1A1A4A01011674: HRF-S-201.-6)

Alzheimer’s disease (AD) is the most common type of presenile and senile dementia. Human β-amyloid precursor cleavage enzyme (BACE-1) is a key enzyme responsible for amyloid plaque production. We assessed anti-BACE-1 and behavioral activities of curcuminoids from Curcuma longa, curcumin (CCN), demethoxycurcumin (DMCCN), and bisdemethoxycurcumin (BDMCCN) against AD fly models. Neuro-protective ability of curcuminoids was assessed using fly model system overexpressing BACE-1 and its substrate APP in compound eyes and entire neurons. BDMCCN has the strongest inhibitory activity toward BACE-1 with 17 μM IC50, which was 20 and 13 times lower than those of CCN and DMCCN respectively. Expression of APP/BACE-1 resulted in the progressive and measurable defects in morphology of eyes and locomotion. Supplementing diet with either 1 mM BDMCCN or CCN rescued APP/BACE1 expressing flies and kept them from developing both morphological and behavioral defects. Structural characteristics and hydrophobicity appear to play a role in determining inhibitory potency of curcuminoids on BACE-1.

Phytoncides are volatile substances diffused largely from trees to protect themselves against harmful factors. Many people are attracted to forest bathing and the effects of forest bathing involve the effect of protecting human dermal cell against reactive oxygen species (ROS), the activation of immune function and the reduction of stress hormones. Since phytoncides are released to prevent plants from rotting or being eaten by animals, we expect that phytoncides have negative effects on insects. However, there is almost no study to show the effects of phytoncides of Chamaecyparis obtusa on insects so far. Therefore, we examined the effects of phytoncides on insects using fruit fly, Drosophila melanogaster. Our results showed that the exposure to phytoncides scents reduced the lifespan of Drosophila in a dose-dependent manner. Moreover, development rate, locomotion and fecundity of fruit flies were also decreased with phytoncides exposure. In food preference test, fruit flies and house flies showed strong avoidance behavior to the food containing phytoncides in a dose dependent manner. Overall, these results suggest the possibility of phytoncides as human-friendly insect repellent.

Early onset torsion dystonia is caused by mutations in DYT1 gene in humans. The molecular and cellular etiology underlying this disorder is not still understood yet. Because vertebrates have more than 4 homologs in their genomes, it is very hard to elucidate the exact in vivo functions of Torsin1A. Instead, Drosophila has only one homolog named Torsin. To investigate the in vivo functions of Torsin, we generated and characterized transgenic flies expressing coding regions of Drosophial Torsin (DTor) cDNA or double stranded inhibitory DNA constructs (RNAi). The transgenic expression of DTor cDNA or RNAi in all tissue induced significant changes in DTor proteins levels as well as ability of motor controls. In addition, DTor over-expressing flies showed increased resistance to H2O2 or paraquat. In the future study, we will found how those phenotypes were accomplished by performing various experiments.

Food limitation is the most common environmental challenge faced by animals and the capacity of animals to survive prolonged periods of starvation is linked to their diet and nutritional status. The objective of this study is to investigate the effects of nutrition on starvation resistance in Drosophila melanogaster. Experimental flies were given ad libitum access to artificial diets differing in concentrations and ratios of protein and carbohydrate for 5 days before they were assayed for starvation time, body composition and life-history parameters. Starvation resistance in Drosophila was greatly influenced by the dietary protein:carbohydrate (P:C) ratio, but neither by the caloric content of the diet nor by dietary carbohydrate alone. Starvation resistance was strongest at the lowest P:C ratio and declined with rising P:C ratio. While starving, Drosophila underwent a dramatic transition in the utilization of physiological fuels, switching from the early phase characterized by preferential consumption of non-lipid substrates to the next phase in which they began to mobilize lipids as fuels for enduring starvation. Our results highlight the importance of nutrition as a key factor determining starvation responses of Drosophila.

An assessment was made of beta-site amyloid precursor protein (APP) cleaving enzyme (BACE1) inhibitory, feeding, climbing activities and lifespan of the diarylalkyls curcumin (CCN), demethoxycurcumin (DCCN) and bisdemethoxycurcumin (BDCCN) identified in the rhizomes of Curcuma longa. Based on IC50 values, BDCCN (0.024 mM) was the most inhibitory constituent, followed by DCCN (0.31 mM) and CCN (0.59 mM). Overall the three curcuminoids were significantly less inhibitory than BACE1 inhibitor IV isophthalamide (8.5 × 10-5 mM). The expression of human APP and BACE1 in compound eye of Drosophila melangaster presented rough abnormal ommatidial lattice. Co-expression of APP and BACE1 within the developing nervous system of drosophila showed climbing defects. These transgenic flies kept on media containing 1 mM of CCN and BDCCN were observed to ameliorate eye degeneration, significantly suppress locomotive dysfunctions, and increase media life time, as well as isophthalamide. CCN and BDCCN as human BACE1 inhibitory constituents may be used as potential therapeutics or lead molecules to develop Alzheimer's disease treatment drugs.

I conducted experiments in Drosophila to investigate the consequences of altered acetylcholinesterase (AChE) activity in the nervous system. In ace hypomorphic mutant larvae, the amount of ace mRNA and the activity of AChE both in vivo and in vitro were significantly reduced compared with those of controls. Reduced Ace in Drosophila larvae resulted in significant down-regulation of branch length and the number of boutons in Type 1 glutamatergic neuromuscular junctions (NMJs). These defects in ace hypomorphic mutant larvae were suppressed when Musca domestica AChE was transgenically expressed. Because AChE inhibitors are utilized for medications for Alzheimer’s disease, we investigated whether pharmacological inhibition of AChE activity induced any synaptic defects. I found that controls exposed to a sublethal dose of DDVP phenocopied the synaptic structural defects of the ace hypomorphic mutant. These results suggest that down-regulation of AChE activity, regardless of whether it is due to genetic or pharmacological manipulations, results in altered synaptic architecture. This study suggests that exposure to AChE inhibitors for 6-12 months may induce altered synaptic architectures in human brains with Alzheimer’s diseases, similar to those reported here. These changes may underlie or contribute to the loss of efficacy of AChE inhibitors after prolonged treatment.

Cinnamaldehyde as the main component of Cinnamomum plants is well known as mammalian transient receptor potential ankyrin 1 (TRPA1) agonist, also activated by low temperature stimuli and mechanosensation. The other TRP subfamily, transient receptor potential vanilloid-1 (TRPV1) sensitive to pungent compounds such as capsaicin and allicin mediates the feeling of warmth. Both TRPA1 and TRPV1 channels are abundantly distributed in sensory neurons. Thus, there is possibility that these channels modulate repellent behaviors of mosquitoes and Drosophila through olfactory receptor neurons (ORNs). In order to confirm this hypothesis, we carried out laboratory repellent tests with cinnamaldehyde to Aedes aegypti females using arm-in-cage test and to a wild type and two TRP channel mutants Drosophila lines using a choice assay. Cinnamaldehyde showed strong repellency against Ae. aegypti and Drosophila wild adults at tested concentrations. However, a mutant fly line did not discriminate or detect the existence of the repellent. These behavioral data suggest that cinnamaldehyde may directly target the TRP channel. More studies to elucidate neural correlates of repellency to ainnamaldehyde compound are as follows: 1) Identifying the ORNs mediating cinnamaldehyde detection using single-sensillum recording techniques, 2) Co-localization of TRP genes on olfactory organs of Ae. aegypti and Drosophila using in situ hybridization and 3) Whether the Aedes TRP homologs might function in cinnamaldehyde repellency using rescued TRP chennels of Drosophila.

Upon mating, females of many animal species undergo dramatic changes in their behavior. In Drosophila melanogaster, post-mating behaviors are triggered by sex peptide (SP), a key modulatory substance produced in the male seminal fluid and transferred to female during copulation. SP modulates female behaviors by acting on the sex peptide receptor (SPR) located in a small subset of internal sensory neurons that innervate the female uterus and project to the central nervous system (CNS). Interestingly, however, SPR is also expressed broadly in the CNS of both sexes. Moreover, SPR is also encoded in the genomes of insects that lack obvious SP orthologs. Based on these observations, we speculated that SPR may have additional ligands that are only distantly related to SP, if at all. If so, then this also raises questions on the evolution of SP-SPR signaling. To begin to address these questions, we set out to identify additional ligands for SPR. Here, we identify myoinhibitory peptides (MIPs) as a second family of SPR ligands that is conserved across a wide range of invertebrate species. MIPs are potent agonists for Drosophila, Aedes and Aplysia SPRs in vitro, yet are unable to trigger post-mating responses in vivo. In contrast to SP, MIPs are not produced in male reproductive organs, and are not required for post-mating behaviors in Drosophila females. We conclude that MIPs are evolutionarily conserved ligands for SPR, which are likely to mediate functions other than the regulation of female reproductive behaviors. Therefore, we propose that SPR has a different ancestral function, with a role in post-mating behavior arising only recently in Drosophila evolution, concomitant with the emergence of its novel SP ligand.

Inflammatory bowel disease (IBD) is a group of chronic disorders of unknown etiology characterized by inflammation of the gastrointestinal tract. Recent data showed that the development of IBD is associated with the interplay of genetic, bacterial, and environmental factors and dysregulation of the intestinal immune system. We investigated how the gut cells were repaired after injury in Drosophila melanogaster. In this study we made D. melanogaster intestine damage model by oral feeding with variety IBD inducer such as pathogenic bacteria Serratia marcescens, Dextran Sulfate Sodium (DSS) and bleomycin, because its function is very similar with human, even though D. melanogaster has relatively simple organism. We repeated oral feeding with variety IBD inducer and got the survival rate and 50% lethal dose (LD50). After feeding with IBD inducer, we investigated the change of the intestinal stem cells, innate immune-related gene expression, and apoptosis in D. melanogaster gut. We examined the Delta, stem cell marker, staining image in the gut after feeding with DSS and S. marcescens with LD50 concentration. The Delta positive cells greatly increased in gut cells damaged by DSS or S. marcescens. This result supports the idea that intestinal gut stem cells are increased after gut cell damage and play very important role in damaged cell repair. Expression level of antimicrobial peptides was dramatically up-regulation after gut damage. As a result of TUNEL (terminal deoxynucleotidyl transferase mediated X-dUTP nick end labeling) assay, we confirmed that cell death by apoptosis was very increased in DSS feeding flies. Accordingly, we suggest that D. melanogaster is a proper IBD model organism to study how intestine damage can be repaired.