Adult Flies Research Articles

BdcSP10 is a prophenoloxidase-activating protease in Bactrocera dorsalis

Insects rely on a powerful and efficient innate immune system against microbial invaders. One of the most important immune processes is the melanization reaction, in which eumelanin is synthesized and deposited on the physically injured site or the surface of invading pathogens. The melanization reaction is mediated by prophenoloxidase (PPO), which is synthesized as an inactive zymogen and requires proteolytic activation through a clip serine protease cascade. This cascade has been characterized in several Lepidoptera insect species, but it is less understood in most Diptera insects. Here, with the means of reverse genetics and biochemistry, we characterized the function of a clip serine protease BdcSP10 from the oriental fruit fly Bactrocera dorsalis (Hendel), a significant agriculture pest to a broad variety of fruit and vegetable crops. BdcSP10 knockdown inhibited the melanization reaction and rendered adult flies more vulnerable to pathogenic infections. In addition, purified and activated BdcSP10 proteases promoted the melanization reaction in larval hemolymph and directly cleaved and activated purified PPO1 and PPO2 in vitro. Taken together, we identified BdcSP10 as a PPO-activating protease and validated its important role in the defense against microbial infection in B. dorsalis. This work broadens the understanding of the activation mechanism of the melanization reaction in Diptera insects.

PSXIII-B-1 Black Soldier fly Larvae Were More Digestible Than Adult Flies, and Nutrient Disappearance in Black Soldier fly Larvae can be Predicted Using Acid Detergent Fiber Based on in Vitro Assays for Pigs

Abstract The objectives were to evaluate the nutrient utilization of fish meal, black soldier fly (BSF, Hermetia illucens) larvae, and adult BSF meal and to develop equations for estimating in vitro nutrient disappearance of BSF larvae for pigs. Two-step and 3-step in vitro procedures were used to simulate the digestion and absorption of nutrients in the gastrointestinal tract of pigs. In Exp. 1, defatted BSF larva meal had less (P < 0.05) in vitro ileal disappearance (IVID) of dry matter (DM; 81.2% vs. 91.6% and 61.6%) and crude protein (CP; 81.8% vs. 92.2% and 67.2%) and in vitro total tract disappearance (IVTTD) of DM (82.6% vs. 93.6% and 65.7%) and organic matter (OM; 78.1% vs. 91.5% and 63.2%) than fish meal and greater (P < 0.05) values than adult BSF. In Exp. 2, CP concentrations in BSF larvae were negatively correlated with ether extract (r = −0.91) but positively correlated with acid detergent fiber (ADF; r = 0.98) and chitin (r = 0.95). Acid detergent fiber and chitin concentrations in BSF larvae were negatively correlated with IVID of DM (r = −0.98 and −0.88) and CP (r = −0.87 and −0.84) and IVTTD of DM (r = −1.00 and −0.94) and OM (r = −0.99 and −0.98). Equations for in vitro nutrient disappearance of BSF larvae using ADF (% DM) as an independent variable were developed: IVID of CP, % = −0.95×ADF + 95 (r2 = 0.75 and P = 0.058) and IVTTD of OM, % = −2.60×ADF + 115 (r2 = 0.98 and P < 0.01). In conclusion, in vitro nutrient utilization of defatted BSF larva meal was less compared with fish meal but was greater compared with adult flies and in vitro nutrient utilization of BSF larvae can be predicted using ADF as an independent variable.

PSXVI-13 Standardized Ileal Digestibility of Amino Acids in Fish Meal, Defatted Black Soldier fly Larva Meal and Adult Black Soldier fly fed to Pigs

Abstract The objective was to determine standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AA) in fish meal, defatted black soldier fly (BSF; Hermetia illucens) larva meal, and adult BSF fed to pigs. Eight barrows with an initial body weight of 72.6 kg (SD = 10.4) fitted with T-cannulas in the distal ileum were individually housed in pens that were equipped with a feeder and a nipple drinker. The pigs were allotted to a replicated 4 × 5 incomplete Latin square design with 4 diets and 5 periods. Three experimental diets containing fish meal (68.6% CP, 5.24% Lys, and 7.5% ether extract), defatted BSF larva meal (59.5% CP, 3.82% Lys, and 7.6% ether extract), and adult BSF (59.0% CP, 2.80% Lys, and 26.8% ether extract) as the sole source of AA were prepared. Additionally, a nitrogen-free diet was formulated to determine the basal endogenous losses of CP and AA. All diets contained 0.5% chromium oxide as an indigestible index. Each period consisted of 4 days of adaptation and 2 days of ileal digesta collection. The SID of CP in defatted BSF larva meal was less (73.8% vs. 88.3%; P < 0.05) than that in fish meal but was greater (P < 0.05) than that in adult BSF (56.1%). The SID of all indispensable AA except for Met and Phe in defatted BSF larva meal was less (P < 0.05) than that in fish meal. The SID of all AA in defatted BSF larva meal was greater (P < 0.05) than that in adult BSF. In conclusion, AA in defatted BSF larva meal are less digestible than those in fish meal when fed to pigs but are more digestible than those in in adult BSF.

Capture of Anastrepha striata Schiner1 with Pheromones and Organic Insecticides and Guava Phenology

Guava (Psidium guajava L.) is an economically important crop in the State of Guerrero. A study was done in a commercial guava orchard with a history of severe damage from fruit fly infestations, in the town of Coaxtlahuacán, municipality of Mochitlán, Guerrero. The objective of the experiment was to evaluate incorporation of recycled plastic artisan traps with chemical attractants for pest management. Treatments were the attractant CeraTrap® and the insecticide Azanim® in the traps. Infestations were evaluated every 15 days from July 2018 to February 2019, with the number of flies captured and phenology of guava plants recorded. Data were subjected to analysis of variance (ANOVA) and Tukey means test (P ≤ 0.05). Months with most pests were July (960 adult flies) and December (1,057 adult flies); treatments with greatest efficiency as attractants were 100 ml of CeraTrap® and 150 ml of CeraTrap® (18.74 and 21.49 flies per trap, respectively).

Metabolic reserves of diapausing western cherry fruit fly (Diptera: Tephritidae) pupae in relation to chill duration and post-chill rearing conditions.

How different macronutrients are utilized at various stages of pupal diapause and the effects of winter length on nutrient reserves remain poorly studied for most insects. Western cherry fruit fly, Rhagoletis indifferens (Diptera: Tephritidae), is a specialist on cherries in higher latitudes or elevations in western North America that exhibits a obligate pupal diapause requiring chilling before adult development can occur. We determined the relationship between metabolic reserves and diapause status in R. indifferens pupae, testing the hypotheses that lipids are the primary reserves utilized during diapause and that long periods of warmth deplete these reserves more than periods of cold. Effects of 0- to 20-week durations at 3°C and subsequent exposure to 23°C and 16:8 L:D (warm rearing conditions) for 0 to 7 weeks on lipid, protein, soluble carbohydrates, and glycogen reserves of R. indifferens pupae were determined. During diapause, lipid reserves were the primary source of energy utilized by R. indifferens, while protein and soluble carbohydrates levels were stable throughout diapause and thus less utilized. At post-diapause, glycogen levels fluctuated the most, indicating that lipid reserves were utilized to produce glycogen to support metabolism for adult fly development. Unchilled pupae did not deplete lipid reserves, unlike chilled pupae, likely because unchilled pupae remained in diapause. Rhagoletis indifferens may have evolved a nutrient utilization strategy typical of rigid diapausing insects in higher latitude environments.

Effect of alloxan on the locomotor ability and developmental stages of Drosophila melanogaster (Oregon-R)

BackgroundVarious bleaching agents are used in food industries among which some reacts to form alloxan. Therefore, the alloxan can indirectly enter a human body and thus form an important aspects for studying its effect on the development. In the present study, the effect of alloxan was studied on the climbing ability, pupation and emergence of flies. Fifty first instar larvae were introduced separately in the vials containing 0.001, 0.002, 0.003 and 0.004 M of alloxan. Then, the duration of pupation as well as the emergence of flies was noted each day till 20 days. The climbing assay was performed on the emerged flies.ResultsThe results suggest that alloxan at 0.002, 0.003 and 0.004 M is potent in inducing the delay in pupation, emergence (of adult flies) and decreased locomotor activity of Drosophila melanogaster.ConclusionsAlloxan exhibits toxic effects at 0.002, 0.003 and 0.004 M in Drosophila.

The Drosophila melanogaster ACE2 ortholog genes are differently expressed in obesity/diabetes and aging models: Implications for COVID-19 pathology

The Spike glycoprotein of SARS-CoV-2, the virus responsible for coronavirus disease 2019, binds to its ACE2 receptor for internalization in the host cells. Elderly individuals or those with subjacent disorders, such as obesity and diabetes, are more susceptible to COVID-19 severity. Additionally, several SARS-CoV-2 variants appear to enhance the Spike-ACE2 interaction, which increases transmissibility and death. Considering that the fruit fly is a robust animal model in metabolic research and has two ACE2 orthologs, Ance and Acer, in this work, we studied the effects of two hypercaloric diets (HFD and HSD) and aging on ACE2 orthologs mRNA expression levels in Drosophila melanogaster. To complement our work, we analyzed the predicted binding affinity between the Spike protein with Ance and Acer. We show for the first time that Ance and Acer genes are differentially regulated and dependent on diet and age in adult flies. At the molecular level, Ance and Acer proteins exhibit the potential to bind to the Spike protein in different regions, as shown by a molecular docking approach. Acer, in particular, interacts with the Spike protein in the same region as in humans. Overall, we suggest that the D. melanogaster is a promising animal model for translational studies on COVID-19 associated risk factors and ACE2.

APKC regulates apical constriction to prevent tissue rupture in the Drosophila follicular epithelium

Apical-basal polarity is an essential epithelial trait controlled by the evolutionarily conserved PAR-aPKC polarity network. Dysregulation of polarity proteins disrupts tissue organization during development and in disease, but the underlying mechanisms are unclear due to the broad implications of polarity loss. Here, we uncover how Drosophila aPKC maintains epithelial architecture by directly observing tissue disorganization after fast optogenetic inactivation in living adult flies and ovaries cultured exvivo. We show that fast aPKC perturbation in the proliferative follicular epithelium produces large epithelial gaps that result from increased apical constriction, rather than loss of apical-basal polarity. Accordingly, we can modulate the incidence of epithelial gaps by increasing and decreasing actomyosin-driven contractility. We traced the origin of these large epithelial gaps to tissue rupture next to dividing cells. Live imaging shows that aPKC perturbation induces apical constriction in non-mitotic cells within minutes, producing pulling forces that ultimately detach dividing and neighboring cells. We further demonstrate that epithelial rupture requires a global increase of apical constriction, as it is prevented by the presence of non-constricting cells. Conversely, a global induction of apical tension through light-induced recruitment of RhoGEF2 to the apical side is sufficient to produce tissue rupture. Hence, our work reveals that the roles of aPKC in polarity and actomyosin regulation are separable and provides the first invivo evidence that excessive tissue stress can break the epithelial barrier during proliferation.

Quality control traceability during the packing and release process of Ceratitis capitata for sterile insect technique

AbstractIn programmes applying the sterile insect technique (SIT), the quality of insects deployed in the field determines the success in preventing, suppressing, containing or eradicating the pest population. In the fruit fly emergence and release facility (ERF) of the Moscamed Program in Mexico, irradiated pupae of Ceratitis capitata are packed in Mexico‐type towers, and key adult quality parameters, such as emergence, fliers and survival, are determined throughout the packing, handling and release process. However, different methodologies are used to estimate the percentage of fliers in the different stages of the process, raising doubts of whether observed differences are due to the effect of each stage or to the methodology used. With this in mind, we developed an alternative called ‘Adult Flier device’ (=AF‐device) to evaluate the adult flier parameter following a critical evaluation path of five steps: (1) upon arrival at ERF, (2) post‐packing, (3) post‐holding, (4) post‐chilling and (5) post‐release, where adult fliers and survival under stress were evaluated. We also compared the current methodologies for the estimation of ‘absolute fliers’ available in different operating manuals. Our results suggest that the AF‐device allows reliable traceability of sterile insect quality parameters throughout the packing and release process, since no significant differences were observed with the control treatments. In the chilling stage, the five methodologies tested were equivalent, but the AF‐device was less time‐consuming and required less manpower and biological material than the other methodological options. Our results demonstrate that the use of the AF‐device can be a feasible, versatile, innovative and efficient alternative to evaluate quality control parameters throughout the process of packing and releasing sterile insects, providing reliable results in a timely manner with less hand labour using minimal biological material.

Evaluation of Methyl Eugenol Doses against Bactrocera zonata S. (Diptera: Tephritidae) in Ber fruit Orchard in Bahawalpur, Pakistan

Among the fruit flies, Bactrocera zonata S. (Diptera: Tephritidae) is native to South and Southeast Asia. It is commonly found in India and Pakistan but it is also found in more than 20 countries in Asian and African regions. In this study, fruit fly male annihilation traps containing different doses of methyl eugenol (ME) attractant, ranging from 0.1, 0.2, 0.3, 0.4, 0.5, 0.75, 1.0 ml dose, and a control treatment (water only) were analyzed. Additionally, a uniform application of one milligram of toxicant Trichlorfon applied in all traps was installed in a Ber orchard in Bahawalpur, Pakistan. The prime purpose of this study was to evaluate the relative efficacy of ME doses against B. zonata in this region. Apart from this, knowledge of seasonal population change could help in controlling these pest insects. Therefore, experiment data for the population was recorded on fortnightly basis from Feb 7, 2018-April 04, 2018 and onward on a weekly basis till May16, 2021 after which the population started to decline. No fruit fly adults were attracted to traps containing water only during all observed dates. Maximum population of B. zonata on Feb 7, 2018, was 3 at ME concentrations of 0.2 ml, 0.75 ml, and 1.0 ml, on Feb 21, 2018, its population was 0.667 at 0.2 ml concentration, on March 07, 2018 the population was 14.667 at 1.0 ml concentration, on March 21, 2018, the population was 3.667 at 0.5 ml concentration, on April 04, 2018, the population was 60.333, on April 11, 2018, the population was 69.000 at 1.0 ml concentration, on April 18, 2018, the population was 94.667 at 0.5ml concentration, on April 26, 2018, the population was 400.670, on May 02,2018, the population was 247.333, on May 9, 2018, the population was 181.667, and on May16, 2018, population was 20.667 at 1.0 ml concentration of methyl eugenol. Thus, more concentrations of ME usually attracted more flies. B. zonata population remained low in February and March. In April the population started to build up and reached its peak at the end of April. In May, the population started to decrease and it declined after mid-May. Correlation with weather factors showed that temperature had a positive while relative humidity showed a negative effect on B. zonata population. This above collected data gave useful information about the population dynamics of fruit flies in the Asian region and an effective attractant dose for the better management of these fruit flies.

Toxicity and sublethal effects of diafenthiuron on life table parameters of Musca domestica L. (Diptera: Muscidae)

Housefly, Musca domestica L. (Diptera: Muscidae), is an important insect-pest owing to its disease transmitting capability in both humans and animals e.g. diarrhea, gastroenteritis diseases, lumpy skin disease, cholera. Residual insecticides are widely used to control houseflies that pose serious threat to human and animal health as well as to the environment. The population resurgence after insecticidal spray is also a common problem in many cases. Transgenerational studies can be very helpful to see the fate of insecticidal sprays. In the current study, we determined transgenerational effects of sublethal doses of diafenthiuron using Age-stage two-sex life table analysis, while focusing on potential use of diafenthiuron in baits. After treating adult flies with three different doses of diafenthiuron viz. LC10, LC20 and LC50, the progeny depicted significant changes regarding pre-adult duration (shorter in control), male and female longevity of their progeny were observed (more adult longevity in control). Additionally, population growth parameters viz. intrinsic rate of growth (r) (−0.03-0.12 per day), net reproductive rate (R0) (0.50–9.98), limiting rate of growth (λ) (0.96–1.13 per day) were also significantly reduced in the progeny of treated adults. Based on the decreased biotic potential i.e. intrinsic rate of growth and other population parameters, diafenthiuron can be recommended as an effective insecticide even at lower doses.

The recurrent de novo c.2011C>T missense variant in MTSS2 causes syndromic intellectual disability

MTSS2, also known as MTSS1L, binds to plasma membranes and modulates their bending. MTSS2 is highly expressed in the central nervous system (CNS) and appears to be involved in activity-dependent synaptic plasticity. Variants in MTSS2 have not yet been associated with a human phenotype in OMIM. Here we report five individuals with the same heterozygous de novo variant in MTSS2 (GenBank: NM_138383.2: c.2011C>T [p.Arg671Trp]) identified by exome sequencing. The individuals present with global developmental delay, mild intellectual disability, ophthalmological anomalies, microcephaly or relative microcephaly, and shared mild facial dysmorphisms. Immunoblots of fibroblasts from two affected individuals revealed that the variant does not significantly alter MTSS2 levels. We modeled the variant in Drosophila and showed that the fly ortholog missing-in-metastasis (mim) was widely expressed in most neurons and a subset of glia of the CNS. Loss of mim led to a reduction in lifespan, impaired locomotor behavior, and reduced synaptic transmission in adult flies. Expression of the human MTSS2 reference cDNA rescued the mim loss-of-function (LoF) phenotypes, whereas the c.2011C>T variant had decreased rescue ability compared to the reference, suggesting it is a partial LoF allele. However, elevated expression of the variant, but not the reference MTSS2 cDNA, led to similar defects as observed by mim LoF, suggesting that the variant is toxic and may act as a dominant-negative allele when expressed in flies. In summary, our findings support that mim is important for appropriate neural function, and that the MTSS2 c.2011C>T variant causes a syndromic form of intellectual disability.

Carrion flies (Insecta: Diptera) found on human cadavers in Chiba prefecture, Honshu, Japan, with the first record of Fannia prisca from a human corpse.

Forensic entomology (FE) involves the collection and analysis of necrophagous insects and arthropods for postmortem interval estimation based on their growth and succession. In Japan, research on FE is limited, and the predominant species of necrophagous insects and their distribution have not been clarified. The present study aimed to clarify the actual situation of insects, targeting Diptera collected from human cadavers, in Chiba Prefecture. We targeted the cases for which specimens could be collected from forensic autopsies conducted at the Legal Medicine Department of Chiba University Graduate School of Medicine or from human bodies handled by the Chiba Police in 2019. We specifically chose cases from which adult insects could be bred. Fifty cases were applicable, and 47 cases were successful in rearing adult flies. Sixteen species of Diptera were identified: six species of Calliphoridae, four species of Sarcophagidae, and a few species of Fanniidae, Muscidae, Phoridae, Piophilidae, and Stratiomyidae. The most frequently observed species were Lucilia sericata (20 cases) and Chrysomya pinguis (18 cases). For the first time, globally, we recorded the presence of Fannia prisca in a human cadaver. In conclusion, this is the first report to reveal the presence of carrion flies in human death cases in Chiba Prefecture, Japan. Research in FE is important in the context of the Japanese natural and social environment since this can aid forensic investigations conducted by authorities.

Establishing and characterising a new cell line from Calliphora vicina (diptera: calliphoridae) fly embryonic tissues

Insect cell lines represent a promising and expanding field as they have several research applications including biotechnology, virology, immunity, toxicology, cell signalling mechanisms and evolution. They constitute a powerful tool having a direct impact on human and veterinary medicine and agriculture. Although more than 1000 cell lines have currently been established from various insect species, Calliphora vicina-derived fly cell lines are lacking. This study was aimed at establishing a new C. vicina embryonic tissue-derived cell line. Adult flies were collected and embryonated eggs were mechanically homogenised and seeded in four types of culture media (L15, Grace's insect medium, Grace's/L15 and DMEM). Cell growth and morphological characteristics were recorded and cytogenetic and molecular patterns were determined. The CV-062020-PPB cell line was established and was shown to have optimal growth in Grace's/L15 medium. CV-062020-PPB cell monolayers that had been sub-cultured over 16 times consisted of firmly adhering cells having different morphologies; a fibroblast-like shape dominated and the karyotype had a 12-chromosome diploid number. RAPD-PCR analysis of the CV-062020-PPB cell line revealed a high similarity index and strong intraspecific relationship with C. vicina adult flies and a weaker relationship with the Lutzomyia longipalpis-derived cell line (Lulo). The CV-062020-PPB cell line constitutes the first cell line obtained from C. vicina embryonic tissues and represents an important basic and applied research tool.

Peppers in Diet: Genome-Wide Transcriptome and Metabolome Changes in Drosophila melanogaster.

The habanero pepper (Capsicum chinense) is an increasingly important spice and vegetable crop worldwide because of its high capsaicin content and pungent flavor. Diets supplemented with the phytochemicals found in habanero peppers might cause shifts in an organism’s metabolism and gene expression. Thus, understanding how these interactions occur can reveal the potential health effects associated with such changes. We performed transcriptomic and metabolomic analyses of Drosophila melanogaster adult flies reared on a habanero pepper diet. We found 539 genes/59 metabolites that were differentially expressed/accumulated in flies fed a pepper versus control diet. Transcriptome results indicated that olfactory sensitivity and behavioral responses to the pepper diet were mediated by olfactory and nutrient-related genes including gustatory receptors (Gr63a, Gr66a, and Gr89a), odorant receptors (Or23a, Or59a, Or82a, and Orco), and odorant-binding proteins (Obp28a, Obp83a, Obp83b, Obp93a, and Obp99a). Metabolome analysis revealed that campesterol, sitosterol, and sucrose were highly upregulated and azelaic acid, ethyl phosphoric acid, and citric acid were the major metabolites downregulated in response to the habanero pepper diet. Further investigation by integration analysis between transcriptome and metabolome data at gene pathway levels revealed six unique enriched pathways, including phenylalanine metabolism; insect hormone biosynthesis; pyrimidine metabolism; glyoxylate, and dicarboxylate metabolism; glycine, serine, threonine metabolism; and glycerolipid metabolism. In view of the transcriptome and metabolome findings, our comprehensive analysis of the response to a pepper diet in Drosophila have implications for exploring the molecular mechanism of pepper consumption.

Fruit fly (Diptera: Tephritidae) Fauna of Amasya and Samsun Provinces, with Two New Records for Turkey

In this study, the fruit fly (Diptera: Tephritidae) fauna of Amasya and Samsun Provinces were determined by adult fruit fly specimens collected from host plants in spring and summer between 2015 and 2018. The specimens were collected from host plants with sweeping nets, and killed in ethyl acetate jars. The collected materials were examined as morphological and the species were diagnosed under a stereo microscope. Fifty-six species and 21 genera belonging to five subfamilies were determined for the fruit fly fauna of Amasya and Samsun Provinces. The genera Anomoia Walker and Philophylla Rondani as well as the species Anomoia purmunda (Harris) and Philophylla caesio (Harris) are recorded for the first time for the fauna of Turkey. Material examined and wing photographs belonging to all the species determined in research region are given. In addition to adult body and aculeus figures, their host plants and zoogeographic distribution of the new record species are presented for the fauna of Turkey.

Effects of four chemosterilants on Bactrocera tau

Bactrocera tau (Walker) is a fly pest species mainly distributed in Southeast Asia and the South Pacific; it causes substantial ecological and economic issues because of its destructiveness and rapid reproduction. Chemical sterilization technology can reduce the use of insecticides and is widely applied for insect pest control. In this study, the sterilization efficacy of varying concentrations of four chemosterilants, namely, hexamethylphosphoramide (HMPA), CSII Aqua, 5-fluorouracil (5-FU), and colchicine, on adult pumpkin flies was investigated. The results indicated that a solution of 0.03% HMPA had the highest sterilization efficacy. When the number of sterile males was equal to or exceeded 20 times that of untreated males, the hatching rate of offspring eggs was less than 10%. Chemosterilant treatment significantly altered the levels of acid phosphatase (ACP), alkaline phosphatase (AKP), and B. tau vitellogenin (BtVg); these substances have an important impact on reproductive development. The treatment also decreased the size of the reproductive organs (i.e., testes and ovaries). Our results suggest that 0.03% HMPA has unique sterilization properties and may represent a new chemical agent for the control of B. tau populations in agricultural settings.

Excreted secreted products from the parasitic nematode Steinernema carpocapsae manipulate the Drosophila melanogaster immune response

Steinernema carpocapsae is an entomopathogenic nematode (EPN) that rapidly infects and kills a wide range of insect hosts and has been linked to host immunosuppression during the initial stages of infection. The lethal nature of S. carpocapsae infections has previously been credited to its symbiotic bacteria; however, it has become evident that the nematodes are able to effectively kill their hosts independently through their excretion/secretion products (ESPs). Here we examined how the adult Drosophila melanogaster immune system is modulated in response to S. carpocapsae ESPs in an attempt to ascertain individual pathogenic contributions of the isolated compound. We found that the S. carpocapsae ESPs decrease the survival of D. melanogaster adult flies, they induce the expression of certain antimicrobial peptide-encoding genes, and they cause significant reduction in phenoloxidase enzyme activity and delay in the melanization response in males flies. We also report that S. carpocapsae ESPs affect hemocyte numbers in both male and female individuals. Our results indicate the manipulative role of EPN ESPs and reveal sex-specific differences in the host response against nematode infection factors. These findings are beneficial as they promote our understanding of the molecular basis of nematode pathogenicity and the parasite components that influence nematode-host interactions.

Octopamine signaling via OctαR is essential for a well-orchestrated climbing performance of adult Drosophila melanogaster

The biogenic amine octopamine (OA) orchestrates many behavioural processes in insects. OA mediates its function by binding to OA receptors belonging to the G protein-coupled receptors superfamily. Despite the potential relevance of OA, our knowledge about the role of each octopaminergic receptor and how signalling through these receptors controls locomotion still limited. In this study, RNA interference (RNAi) was used to knockdown each OA receptor type in almost all Drosophila melanogaster tissues using a tubP-GAL4 driver to investigate the loss of which receptor affects the climbing ability of adult flies. The results demonstrated that although all octopaminergic receptors are involved in normal negative geotaxis but OctαR-deficient flies had impaired climbing ability more than those deficient in other OA receptors. Mutation in OA receptors coding genes develop weak climbing behaviour. Directing knockdown of octαR either in muscular system or nervous system or when more specifically restricted to motor and gravity sensing neurons result in similar impaired climbing phenotype, indicating that within Drosophila legs, OA through OctαR orchestrated the nervous system control and muscular tissue responses. OctαR-deficient adult males showed morphometric changes in the length and width of leg parts. Leg parts morphometric changes were also observed in Drosophila mutant in OctαR. Transmission electron microscopy revealed that the leg muscles OctαR-deficient flies have severe ultrastructural changes compared to those of control flies indicating the role played by OctαR signalling in normal muscular system development. The severe impairment in the climbing performance of OctαR-deficient flies correlates well with the completely distorted leg muscle ultrastructure in these flies. Taken together, we could conclude that OA via OctαR plays an important multifactorial role in controlling locomotor activity of Drosophila.

Astragalus membranaceus Extract Prevents Calcium Oxalate Crystallization and Extends Lifespan in a Drosophila Urolithiasis Model.

Approximately 1 in 20 people develops kidney stones at some point in their life. Although the surgical removal of stones is common, the recurrence rate remains high and it is therefore important to prevent the occurrence of kidney stones. We chose Astragalus membranaceus (AM), which is a traditional Chinese medicine, to study the prevention of urolithiasis using a Drosophila model based on our previous screening of traditional Chinese herbs. Wild-type Drosophila melanogaster Canton-S adult fruit flies were used in this study. Ethylene glycol (EG, 0.5%) was added to food as a lithogenic agent. The positive control agent (2% potassium citrate (K-citrate)) was then compared with AM (2, 8, and 16 mg/mL). After 21 days, the fruit flies were sacrificed under carbon dioxide narcotization, and the Malpighian tubules were dissected, removed, and processed for polarized light microscopy examination to observe calcium oxalate (CaOx) crystallization. Then, the ex vivo dissolution of crystals in the Malpighian tubules was compared between K-citrate and AM. Survival analysis of the EG, K-citrate, and AM groups was also performed. Both 2% K-citrate and AM (16 mg/mL) significantly inhibited EG-induced CaOx crystal formation. Mean lifespan was significantly reduced by the administration of EG, and the results were significantly reversed in the AM (8 and 16 mg/mL) groups. However, AM extract did not directly dissolve CaOx crystals in Drosophila Malpighian tubules ex vivo. In conclusion, AM extract decreased the ratio of CaOx crystallization in the Malpighian tubules and significantly ameliorated EG-induced reduction of lifespan. AM prevented CaOx crystal formation in the Drosophila model.