Adult Flies (adult + fly)

Distribution by Scientific Domains

Selected Abstracts

Correlated responses to selection for stress resistance and longevity in a laboratory population of Drosophila melanogaster

Abstract Laboratory studies on Drosophila have revealed that resistance to one environmental stress often correlates with resistance to other stresses. There is also evidence on genetic correlations between stress resistance, longevity and other fitness-related traits. The present work investigates these associations using artificial selection in Drosophila melanogaster. Adult flies were selected for increased survival after severe cold, heat, desiccation and starvation stresses as well as increased heat-knockdown time and lifespan (CS, HS, DS, SS, KS and LS line sets, respectively). The number of selection generations was 11 for LS, 27 for SS and 21 for other lines, with selection intensity being around 0.80. For each set of lines, the five stress-resistance parameters mentioned above as well as longevity (in a nonstressful environment) were estimated. In addition, preadult developmental time, early age productivity and thorax length were examined in all lines reared under nonstressful conditions. Comparing the selection lines with unselected control revealed clear-cut direct selection responses for the stress-resistance traits. Starvation resistance increased as correlated response in all sets of selection lines, with the exception of HS. Positive correlated responses were also found for survival after cold shock (HS and DS) and heat shock (KS and DS). With regard to values of resistance across different stress assays, the HS and KS lines were most similar. The resistance values of the SS lines were close to those of the LS lines and tended to be the lowest among all selection lines. Developmental time was extended in the SS and KS lines, whereas the LS lines showed a reduction in thorax length. The results indicate a possibility of different multiple-stress-resistance mechanisms for the examined traits and fitness costs associated with stress resistance and longevity. [source]

Physiological requirement for the glutamate transporter dEAAT1 at the adult Drosophila neuromuscular junction

Thomas Rival
Abstract L -Glutamate is the major excitatory neurotransmitter in the mammalian brain. Specific proteins, the Na+/K+ -dependent high affinity excitatory amino acid transporters (EAATs), are involved in the extracellular clearance and recycling of this amino acid. Type I synapses of the Drosophila neuromuscular junction (NMJ) similarly use L -glutamate as an excitatory transmitter. However, the localization and function of the only high-affinity glutamate reuptake transporter in Drosophila, dEAAT1, at the NMJ was unknown. Using a specific antibody and transgenic strains, we observed that dEAAT1 is present at the adult, but surprisingly not at embryonic and larval NMJ, suggesting a physiological maturation of the junction during metamorphosis. We found that dEAAT1 is not localized in motor neurons but in glial extensions that closely follow motor axons to the adult NMJ. Inactivation of the dEAAT1 gene by RNA interference generated viable adult flies that were able to walk but were flight-defective. Electrophysiological recordings of the thoracic dorso-lateral NMJ were performed in adult dEAAT1-deficient flies. The lack of dEAAT1 prolonged the duration of the individual responses to motor nerve stimulation and this effect was progressively increased during physiological trains of stimulations. Therefore, glutamate reuptake by glial cells is required to ensure normal activity of the Drosophila NMJ, but only in adult flies. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006 [source]

Disruption of insulin pathways alters trehalose level and abolishes sexual dimorphism in locomotor activity in Drosophila

Yesser Hadj Belgacem
Abstract Insulin signaling pathways are implicated in several physiological processes in invertebrates, including the control of growth and life span; the latter of these has also been correlated with juvenile hormone (JH) deficiency. In turn, JH levels have been correlated with sex-specific differences in locomotor activity. Here, the involvement of the insulin signaling pathway in sex-specific differences in locomotor activity was investigated in Drosophila. Ablation of insulin-producing neurons in the adult pars-intercerebralis was found to increase trehalosemia and to abolish sexual dimorphism relevant to locomotion. Conversely, hyper-insulinemia induced by insulin injection or by over-expression of an insulin-like peptide decreases trehalosemia but does not affect locomotive behavior. Moreover, we also show that in the head of adult flies, the insulin receptor (InR) is expressed only in the fat body surrounding the brain. While both male and female InR mutants are hyper-trehalosemic, they exhibit similar patterns of locomotor activity. Our results indicate that first, insulin controls trehalosemia in adults, and second, like JH, it controls sex-specific differences in the locomotor activity of adult Drosophila in a manner independent of its effect on trehalose metabolism. © 2005 Wiley Periodicals, Inc. J Neurobiol, 2006 [source]

Role of the neuropeptide CCAP in Drosophila cardiac function

Davide Dulcis
Abstract The heartbeat of adult Drosophila melanogaster displays two cardiac phases, the anterograde and retrograde beat, which occur in cyclic alternation. Previous work demonstrated that the abdominal heart becomes segmentally innervated during metamorphosis by peripheral neurons that express crustacean cardioactive peptide (CCAP). CCAP has a cardioacceleratory effect when it is applied in vitro. The role of CCAP in adult cardiac function was studied in intact adult flies using targeted cell ablation and RNA interference (RNAi). Optical detection of heart activity showed that targeted ablation of CCAP neurons selectively altered the anterograde beat, without apparently altering the cyclic cardiac reversal. Normal development of the abdominal heart and of the remainder of cardiac innervation in flies lacking CCAP neurons was confirmed by immunocytochemistry. Thus, in addition to its important role in ecdysis behavior (the behavior used by insects to shed the remains of the old cuticle at the end of the molt), CCAP may control the level of activity of the anterograde cardiac pacemaker in the adult fly. Expression of double stranded CCAP RNA in the CCAP neurons (targeted CCAP RNAi) caused a significant reduction in CCAP expression. However, this reduction was not sufficient to compromise CCAP's function in ecdysis behavior and heartbeat regulation. © 2005 Wiley Periodicals, Inc. J Neurobiol, 2005 [source]

Allee effect in larval resource exploitation in Drosophila: an interaction among density of adults, larvae, and micro-organisms

Bregje Wertheim
Abstract 1. Aggregation pheromones can evolve when individuals benefit from clustering. Such a situation can arise with an Allee effect, i.e. a positive relationship between individual fitness and density of conspecifics. Aggregation pheromone in Drosophila induces aggregated oviposition. The aim of the work reported here was to identify an Allee effect in the larval resource exploitation by Drosophila melanogaster, which could explain the evolution of aggregation pheromone in this species. 2. It is hypothesised that an Allee effect in D. melanogaster larvae arises from an increased efficiency of a group of larvae to temper fungal growth on their feeding substrate. To test this hypothesis, standard apple substrates were infested with specified numbers of larvae, and their survival and development were monitored. A potential beneficial effect of the presence of adult flies was also investigated by incubating a varying number of adults on the substrate before introducing the larvae. Adults inoculate substrates with yeast, on which the larvae feed. 3. Fungal growth was related negatively to larval survival and the size of the emerging flies. Although the fungal growth on the substrate was largely reduced at increased larval densities, the measurements of fitness components indicated no Allee effect between larval densities and larval fitness, but rather indicated larval competition. 4. In contrast, increased adult densities on the substrates prior to larval development yielded higher survival of the larvae, larger emerging flies, and also reduced fungal growth on the substrates. Hence, adults enhanced the quality of the larval substrate and significant benefits of aggregated oviposition in fruit flies were shown. Experiments with synthetic pheromone indicated that the aggregation pheromone itself did not contribute directly to the quality of the larval resource. 5. The interaction among adults, micro-organisms, and larval growth is discussed in relation to the consequences for total fitness. [source]

Population persistence of the parasitoid fly Zaira cinerea (Fallén) (Diptera: Tachinidae) utilizing multiple host carabid beetles with different seasonality and quality

Atsushi OHWAKI
Abstract Zaira cinerea (Fallén) is a parasitoid fly (Diptera: Tachinidae) that attacks adult carabid beetles. To better understand mechanisms of population persistence in this species, we examined seasonality of host beetle abundance, the frequency of parasitism, and the timing of fly eclosion. In addition, we evaluated host quality using numbers of larvae or puparia per individual beetle as a measure of quality. The fly parasitized only large carabids (,15 mm body length); the lengths of fly puparia reached 7.4,10.8 mm during development in beetle abdomens, and larger hosts are likely essential. Of the 18 large carabid species collected in this study, we chose two, Carabus maiyasanus Bates and Leptocarabus procerulus (Bates), because they were large and abundant (87% of total catch). The two carabids had different phonologies; C. maiyasanus was abundant from spring to summer, and its abundance dropped sharply in autumn, while L. procerulus was abundant in autumn and rare from spring to summer except July. Parasitism was observed in all the months from May to November except June, and adult flies eclosed more than once a year (in early summer, late summer, and mid-autumn), indicating that the species is multivoltine. Host quality of L. procerulus was higher than that of C. maiyasanus. Carabus maiyasanus was mainly used as a host from spring to summer, and L. procerulus was used in autumn. Thus, adult beetles of one or both species are available over most of spring, summer, and autumn, allowing population persistence of this fly species over time. [source]

slowmo is required for Drosophila germline proliferation

Simon Reeve
Abstract Null mutations in the Drosophila gene, slowmo (slmo), result in reduced mobility and lethality in first-instar larvae. Slowmo encodes a mitochondrial protein of unknown function, as do the two other homologs found in Drosophila. Here, we have studied a hypomorphic P-element allele of slmo demonstrating its effects on germline divisions in both testes and ovaries. Using in situ studies, enhancer-trap activity, and promoter fusions, we have shown that slmo expression in testes is found in the somatic cyst cells (SCC). The hypomorphic allele for Slmo revealed apoptotic loss of germline cells in the larval germline, culminating in a complete absence of the germline in adult flies. In females, a similar degeneration of the germarium is observed, while reporter gene expression is found in both germline and somatic cells. Using a null mutation in female germline clones, we find slmo is dispensable from the germline cells. Our results suggest that Slowmo is not required in germline cells directly, but is required in SCCs responsible for maintaining germline survival in both sexes. genesis 45:66,75, 2007. © 2007 Wiley-Liss, Inc. [source]

Functional analysis of Drosophila melanogaster hexokinase Hex-A locus: multiple Initiator-like elements enhance DPE containing promoter activity

P. C. Jayakumar
Abstract Flight muscle Hexokinase-A (HEX-A) is the most conserved and essential hexokinase isoenzyme among Drosophila species. In this study, the Hex-A locus, encoding the HEX-A isoenzyme, has been analysed for the elements regulating its expression. By sequencing the 5, ends of Hex-A cDNA amplified by 5, RACE, we identified a transcription start site that overlapped the Initiator and downstream promoter elements. A 214 bp sequence, encompassing transcription start sites and promoter elements, was required for minimal promoter activity. DNA sequence to the 5, end of the minimal promoter element did not demonstrate any promoter activity; however, its inclusion with the basal promoter element enhanced the promoter activity. Oligonucleotide competition and site-directed mutagenesis identified the Initiator-like sequences, TCAWT, present in this region that were responsible for enhancing the promoter activity. The Hex-A locus is expressed as a single protein in Drosophila cell line, whereas in pupae, larvae and adult flies, it is expressed as two distinct types. [source]

Genomic organization and functional characterization of the alcohol dehydrogenase locus of Ceratitis capitata (Medfly)

Saverio Brogna
Abstract Approximately 30 kb of genomic DNA enclosing the Adh locus from the medfly, Ceratitis capitata have been cloned and about 15 kb has been structurally and functionally characterized. The locus consists of two genes, Adh-1 and Adh-2, separated by an intergenic region, which is polymorphic in size ranging from , 6.4 kb to 8.1 kb. Both genes consist of three exons and two introns. The introns are below 200 bp in size, except the 1st intron of Adh-1, which is unexpectedly long, variable in size and contains a deleted mariner -like element (postdoc). The two genes are transcribed in different orientations. The Adh-2 gene shows the typical pattern of transcription seen in the homologous genes of Drosophilidae presenting high levels of expression in the fat body, gut and ovaries. The Adh-1 gene is only expressed in the body muscle tissues of embryos, larvae and adult flies, raising the question of what its biological function may be. A DNA fragment containing bases ,102 to ,1666 relative to the first base of the initiating ATG of Adh-1 is sufficient to drive the expression of a reporter gene in body muscles of Drosophila melanogaster embryos, larvae and adult flies. The study provides further insights into the evolution of the Adh genes of higher diptera. [source]

The seasonal abundance of blowflies infesting drying fish in south-west India

R. Wall
Summary 1Blowfly infestation of sun-drying fish is a major economic problem in many developing countries of Asia, Africa and the Pacific. To consider the ecology of infestation, adult and larval blowfly populations were monitored between 27 October 1997 and 27 April 1999 at a fish landing and drying site, approximately 5 km north of Calicut, in Kerala state on the coast of south-west India. 2During the 548-day sampling period, a total of 96 953 adult Diptera was collected from 16 sticky targets, placed inside and outside eight fish-storage sheds. Of these, 91 912 (95%) were Chrysomya megacephala, 3719 (4%) were other Calliphoridae and 1322 (1%) were other species, largely Sarcophagidae. 3The population of C. megacephala showed pronounced seasonal fluctuations in response to climate, particularly relative humidity. Significantly shorter-frequency fluctuations within fish-processing sheds were also evident, the periodicity of which corresponded approximately to C. megacephala generation cycles. Spatial variation in C. megacephala abundance was evident within the site, higher populations occurring closest to the beach and numbers declining with distance inland. 4The pattern of drying fish infestation by C. megacephala broadly followed changes in the density of adult flies and the seasonal change in weather, with peaks during the monsoon and troughs in the dry hot periods. High relative humidity played a significant but secondary role in increasing infestation. 5Quantification of the relationship between larval infestation and percentage fish loss suggests that, given the infestation levels observed, between 10% and 60% post-harvest wet weight losses would be expected in the monsoon period, depending on the species of fish landed. 6The study emphasizes the importance of developing a clear understanding of the basic ecology and spatial and temporal dynamics of an insect pest, prior to the design or implementation of any pest management programme. [source]

Trade-offs between longevity and pathogen resistance in Drosophila melanogaster are mediated by NF,B signaling

AGING CELL, Issue 6 2006
Sergiy Libert
Summary The innate immune response protects numerous organisms, including humans, from the universe of pathogenic molecules, viruses and micro-organisms. Despite its role in promoting pathogen resistance, inappropriate activation and expression of NF,B and other immunity-related effector molecules can lead to cancer, inflammation, and other diseases of aging. Understanding the mechanisms leading to immune system activation as well as the short- and long-term consequences of such activation on health and lifespan is therefore critical for the development of beneficial immuno-modulating and longevity-promoting interventions. Mechanisms of innate immunity are highly conserved across species, and we take advantage of genetic tools in the model organism, Drosophila melanogaster, to study the effects of acute and chronic activation of immunity pathways on pathogen resistance and general fitness of adult flies. Our findings indicate that fat body specific overexpression of a putative pathogen recognition molecule, peptidoglycan recognition protein (PGRP-LE), is sufficient for constitutive up-regulation of the immune response and for enhanced pathogen resistance. Primary components of fitness are unaffected by acute activation, but chronic activation leads to an inflammatory state and reduced lifespan. These phenotypes are dependent on the NF,B-related transcriptional factor, Relish, and they establish a mechanistic basis for a link between immunity, inflammation, and longevity. [source]

Temperature and clinal variation in larval growth efficiency in Drosophila melanogaster

S. J. W. Robinson
Geographic clines in ectotherm species including Drosophila melanogaster have been found throughout the world, with genetically larger body size and shorter development time occurring at high latitudes. Temperature is thought to play a major role in the evolution of this clinal variation. Laboratory thermal selection has effects similar to those seen in geographical clines. Evolution at low temperatures results in more rapid development to larger adult flies. This study investigated the effects of geographical origin and experimental temperature on larval growth efficiency in D. melanogaster. Larvae from populations that had evolved at high latitudes were found to use limited food more efficiently, so that the overall adult body size achieved was larger. Larvae reared at a lower experimental temperature (18 °C) used food more efficiently than those reared at a higher temperature (25 °C). The increases in growth efficiency found in populations from high latitudes could explain their increased body size and more rapid development. [source]

Myiasis as a risk factor for prion diseases in humans

O Lupi
Abstract Prion diseases are transmissible spongiform encephalopathies of humans and animals. The oral route is clearly associated with some prion diseases, according to the dissemination of bovine spongiform encephalopathy (BSE or mad cow disease) in cattle and kuru in humans. However, other prion diseases such as scrapie (in sheep) and chronic wasting disease (CWD) (in cervids) cannot be explained in this way and are probably more associated with a pattern of horizontal transmission in both domestic and wild animals. The skin and mucous membranes are a potential target for prion infections because keratinocytes and lymphocytes are susceptible to the abnormal infective isoform of the prion protein. Iatrogenic transmission of Creutzfeldt,Jakob disease (CJD) was also recognized after corneal transplants in humans and scrapie was successfully transmitted to mice after ocular instillation of infected brain tissue, confirming that these new routes could also be important in prion infections. Some ectoparasites have been proven to harbour prion rods in laboratory experiments. Prion rods were identified in both fly larvae and pupae; adult flies are also able to express prion proteins. The most common causes of myiasis in cattle and sheep, closely related animals with previous prion infections, are Hypoderma bovis and Oestrus ovis, respectively. Both species of flies present a life cycle very different from human myiasis, as they have a long contact with neurological structures, such as spinal canal and epidural fat, which are potentially rich in prion rods. Ophthalmomyiases in humans is commonly caused by both species of fly larvae worldwide, providing almost direct contact with the central nervous system (CNS). The high expression of the prion protein on the skin and mucosa and the severity of the inflammatory response to the larvae could readily increase the efficiency of transmission of prions in both animals and humans. [source]

Lifespan and patterns of accumulation and mobilization of nutrients in the sugar-fed phorid fly, Pseudacteon tricuspis

Henry Y. Fadamiro
Abstract., The effect of sugar feeding on the survival of adult phorid fly Pseudacteon tricuspis is investigated. Flies fed 25% sucrose in aqueous solution continuously throughout their lifespan have greater longevity (mean ± SE longevity: female = 7.9 ± 0.8 days, male = 8.9 ± 0.9 days) than completely starved (provided no water and no sugar solution) flies, sugar-starved (provided water only) flies, or flies fed sugar solution only on their first day of adult life. Completely starved flies rarely lived beyond one day. Provision of water increases longevity by 2 days, and one full day of sugar feeding further increases longevity by an additional 1,2 days. Flies fed 50% sucrose have similar survivorship as those fed 25% sucrose. The temporal patterns of nutrient accumulation and utilization are also compared in P. tricuspis fed different diets: sugar-starved, sucrose-fed on the first day of adult life only, and sucrose-fed continuously. Adult P. tricuspis emerge with no gut sugars, and only minimal amounts of body sugars and glycogen. Although the levels of body sugars and glycogen decline gradually in sugar-starved flies, a single day of sugar feeding results in the accumulation of maximum amounts of gut sugars, body sugars and glycogen. High levels of these nutrients are maintained in female and male phorid flies fed on sucrose continuously over the observation period, whereas nutrient levels decline in flies fed only on the first day of life, beginning 1 day postfeeding. Female and male P. tricuspis emerge with an estimated 12.3 ± 2.3 and 7.2 ± 1 g of lipid reserves per fly, respectively. These teneral amounts represent the highest lipid levels detected in adult flies, irrespective of their diet, and are maintained over the life times of sucrose-fed female and male flies, but declined steadily in sugar-starved females. These data suggest that adult P. tricuspis are capable of converting dietary sucrose to body sugars and glycogen, but not lipids. [source]

Spatial and temporal partitioning of behaviour by adult dacines: direct evidence for methyl eugenol as a mate rendezvous cue for Bactrocera cacuminata

S. Raghu
Abstract., Resource use in adult Dacinae (Diptera: Tephritidae) is believed to be restricted to the host plant (i.e. the plant that provides fruit for oviposition and larval development). However, studies on Bactrocera cacuminata did not support this hypothesis. Thus, it was hypothesized that adult flies partition their diurnal activities between spatially separated resources (host plant, sugar, protein and methyl eugenol) as a function of the physiological status of the fly (immature, mature,unmated, mature,mated). In accordance with a priori predictions, the results of a field-cage study show that there are significant diurnal patterns in abundance and behaviour, and that flies of different physiological status use resources differently. Immature flies spend most of their time foraging for sugar and protein to facilitate development. Sexually mature flies forage for sugars during the day, and at dusk, responded strongly to methyl eugenol and mate. The fact that polygynous males wait at methyl eugenol at dusk whereas the mated, monandrous females spend their time ovipositing in fruit and are nonresponsive to methyl eugenol, supports Metcalf's hypothesis that such phenylpropanoids serve as mate rendezvous cues. [source]

Developmental changes in Drosophila melanogaster following exposure to alternating electromagnetic fields

Ghadire Mirabolghasemi
Abstract This study investigated the biological effects of alternating electromagnetic fields (EMFs) on developmental stages of Drosophila melanogaster eggs and the first, second and third instar larvae stages. D. melanogaster eggs and larval stages were exposed to a 11 mT 50 Hz field produced by a pair of Helmholtz coils. Each stage was exposed to aEMFs for 2, 4, 6 and 8 h. Features of adult flies such as head, thorax, abdomen and other morphological changes were studied and compared. The frequency of abnormal flies was calculated using statistical methods at P,<,.05. The results obtained from exposing larvae in different stages of development showed a significant increase in the number of abnormal adult flies, whereas no significant increase was observed in the group arising from eggs exposed to aEMFs. Also, it appeared that duration of exposure correlates with the increase in the number of abnormal flies. There was no significant difference in mortality rate and sex distribution of the abnormal flies between field exposed and the control groups. Bioelectromagnetics 23:416,420, 2002. © 2002 Wiley-Liss, Inc. [source]

Genetic link between p53 and genes required for formation of the zonula adherens junction

CANCER SCIENCE, Issue 5 2004
Masamitsu Yamaguchi
Ectopic expression of human p53 in Drosophila eye imaginal disc cells induces apoptosis and results in a rough eye phenotype in the adult flies. We have screened Drosophila stocks to identify mutations that enhance or suppress the p53-induced rough eye phenotype. One of the dominant enhancers of the p53-induced rough eye phenotype corresponds to a loss-of-function mutation of the crumbs gene, which is essential for the biogenesis of the zonula adherens junction and the establishment of apical polarity in epithelial cells. Enhancement of p53-induced apoptosis in the eye imaginal discs by a half-reduction of the crumbs gene dose was confirmed by a TUNEL method. Furthermore, mutations of genes for Shotgun (Drosophila E-cadherin) and Armadillo (Drosophila,-catenin), the two main components of the adherens junction, also strongly enhanced the p53-induced rough eye phenotype. These results suggest that human p53 senses subtle abnormality at the adherens junction or in signals derived from the junction, and consequently induces apoptosis to remove abnormal cells from tissue. Thus p53 likely plays a role as a guardian of the tissue not only by sensing the damaged DNA, but also by sensing signals from the adherens junction. [source]

Role of the neuropeptide CCAP in Drosophila cardiac function

Davide Dulcis
Abstract The heartbeat of adult Drosophila melanogaster displays two cardiac phases, the anterograde and retrograde beat, which occur in cyclic alternation. Previous work demonstrated that the abdominal heart becomes segmentally innervated during metamorphosis by peripheral neurons that express crustacean cardioactive peptide (CCAP). CCAP has a cardioacceleratory effect when it is applied in vitro. The role of CCAP in adult cardiac function was studied in intact adult flies using targeted cell ablation and RNA interference (RNAi). Optical detection of heart activity showed that targeted ablation of CCAP neurons selectively altered the anterograde beat, without apparently altering the cyclic cardiac reversal. Normal development of the abdominal heart and of the remainder of cardiac innervation in flies lacking CCAP neurons was confirmed by immunocytochemistry. Thus, in addition to its important role in ecdysis behavior (the behavior used by insects to shed the remains of the old cuticle at the end of the molt), CCAP may control the level of activity of the anterograde cardiac pacemaker in the adult fly. Expression of double stranded CCAP RNA in the CCAP neurons (targeted CCAP RNAi) caused a significant reduction in CCAP expression. However, this reduction was not sufficient to compromise CCAP's function in ecdysis behavior and heartbeat regulation. © 2005 Wiley Periodicals, Inc. J Neurobiol, 2005 [source]

Argemone oil induced cellular damage in the reproductive tissues of transgenic Drosophila melanogaster: Protective role of 70 kDa heat shock protein

Indranil Mukhopadhyay
Abstract We explored the reproductive toxicity of argemone oil and its principal alkaloid fraction in transgenic Drosophila melanogaster (hsp70-lacZ) Bg9. The toxicity of argemone oil has been attributed to two of its physiologically active benzophenanthridine alkaloids, sanguinarine and dihydrosanguinarine. Freshly eclosed first instar larvae of transgenic Drosophila melanogaster were transferred to different concentrations of argemone oil and its alkaloid fraction contaminated food. Virgin flies that eclosed from the contaminated food were pair-mated to look into the effect on reproduction. The study was further extended by investigating hsp70 expression and tissue damage in larval gonads, genital discs, and reproductive organs of adult fly. Our results showed that argemone oil was more cytotoxic than its principal alkaloid fraction. Moreover, it was the male fly that was more affected compared to its opposite number. The accessory glands of male reproductive system of the fly, which did not express hsp70, exhibited severe damage as evidenced by Trypan blue staining. This prompted us to explore the ultrastructural morphology of the gland, which showed acute signs of necrosis in both the cell types as evident by necrotic nuclei, higher vacuolization, and disorganized endoplasmic reticulum, decrease in the number of Golgi vesicles and disorganized, loosely packed filamentous structures in the lumen of the accessory gland, at the higher concentrations of the adulterant. The study showed the reproductive toxicity of argemone oil and its alkaloid fraction in transgenic Drosophila melanogaster and further confirmed the cytoprotective role of hsp70. © 2003 Wiley Periodicals, Inc. J Biochem Mol Toxicol 17:223,234, 2003; Published online in Wiley InterScience ( DOI 10.1002/jbt.10082. [source]