Antimicrobial effects of laurel extract, laurel essential oil, zahter extract, and zahter essential oil on chicken wings contaminated with Salmonella Typhimurium

BACKGROUND

This study aimed to evaluate the antimicrobial effects of zahter extract, zahter essential oil, laurel extract, and laurel essential oil on Salmonella Typhimurium inoculated on chicken wings.

METHODS

A total of 10 groups, including eight study groups and two control groups were formed, consisting of zahter extract and zahter essential oil and laurel extract and laurel essential oil in different proportions. In the study, laurel extract at 6.4% and 12.8% concentrations, laurel essential oil at 0.2% and 0.4% concentrations, zahter extract at 0.2% and 0.4% concentrations, and zahter essential oil at 0.2% and 0.4% concentrations were used.

RESULTS

The broth microdilution method was used to evaluate the antimicrobial activity of the extract and essential oils on the S. Typhimurium. Minimum inhibitory concentrations of the extracts and essential oils used in the study against S. Typhimurium were determined. The highest inhibitory effect on S. Typhimurium was observed in the 0.4% laurel essential oil group. It was determined that the inhibitory effect increased as the concentration of laurel essential oil increased. In addition, the antimicrobial activity of zahter essential oil is less inhibitory than the laurel extract, laurel essential oil, and zahter extract.

CONCLUSION

According to the results of this study, it has been revealed that extracts and essential oils obtained from zahter and laurel plants, which have been shown to be natural antimicrobial, can be used in foods as an alternative to chemical additives. To develop research results, the applicability of these extracts and essential oils in different foodstuffs should be examined using different ingredients and concentrations.

Phenotypic plasticity, canalisation and developmental stability of Triatoma infestans wings: effects of a sublethal application of a pyrethroid insecticide

BACKGROUND

Triatomine control campaigns have traditionally consisted of spraying the inside of houses with pyrethroid insecticides. However, exposure to sublethal insecticide doses after the initial application is a common occurrence and may have phenotypic consequences for survivors. Here, using Triatoma infestans (the main vector of Chagas disease in the Southern Cone of South America) as a model species, we quantified the effects of exposure to a sublethal dose of pyrethroid insecticide on wing morphology. We tested if the treatment (i) induced a plastic effect (change in the character mean); (ii) altered environmental canalisation (higher individual variation within genotypes); (iii) altered genetic canalisation (higher variation among genotypes); and (iv) altered developmental stability (higher fluctuating asymmetry [FA]).

METHODS

Each of 25 full-sib families known to be susceptible to pyrethroid insecticides were split in two groups: one to be treated with a sublethal dose of deltamethrin (insecticide-treated group) and the other to be treated with pure acetone (control group). Wings of the emerging adults were used in a landmark-based geometric morphometry analysis to extract size and shape measurements. Average differences among treatments were measured. Levels of variation among families, among individuals within families and among sides within individuals were computed and compared among treatments.

RESULTS

Wing size and shape were affected by a sublethal dose of deltamethrin. The treated insects had larger wings and a more variable wing size and shape than control insects. For both wing size and shape, genetic variation was higher in treated individuals. Individual variations and variations in FA were also greater in deltamethrin-treated insects than in control ones for all full-sib families; however, the patterns of shape variation associated with genetic variation, individual variation and FA were different.

CONCLUSIONS

Insects exposed to a sublethal dose of deltamethrin presented larger, less symmetrical and less canalised wings. The insecticide treatment jointly impaired developmental stability and genetic and environmental canalisation. The divergent patterns of shape variation suggest that the related developmental buffering processes differed at least partially. The morphological modifications induced by a single sublethal exposure to pyrethroids early in life may impinge on subsequent flight performance and consequently affect the dynamics of house invasion and reinfestation, and the effectiveness of triatomine control operations.

Lepidopteran wing scales contain abundant cross-linked film-forming histidine-rich cuticular proteins

Scales are symbolic characteristic of Lepidoptera; however, nothing is known about the contribution of cuticular proteins (CPs) to the complex patterning of lepidopteran scales. This is because scales are resistant to solubilization, thus hindering molecular studies. Here we succeeded in dissolving developing wing scales from Bombyx mori, allowing analysis of their protein composition. We identified a distinctive class of histidine rich (His-rich) CPs (6%-45%) from developing lepidopteran scales by LC-MS/MS. Functional studies using RNAi revealed CPs with different histidine content play distinct and critical roles in constructing the microstructure of the scale surface. Moreover, we successfully synthesized films in vitro by crosslinking a 45% His-rich CP (BmorCPR152) with laccase2 using N-acetyl- dopamine or N-β-alanyl-dopamine as the substrate. This molecular study of scales provides fundamental information about how such a fine microstructure is constructed and insights into the potential application of CPs as new biomaterials.

Ribosomopathy-associated mutations cause proteotoxic stress that is alleviated by TOR inhibition

Ribosomes are multicomponent molecular machines that synthesize all of the proteins of living cells. Most of the genes that encode the protein components of ribosomes are therefore essential. A reduction in gene dosage is often viable albeit deleterious and is associated with human syndromes, which are collectively known as ribosomopathies1-3. The cell biological basis of these pathologies has remained unclear. Here, we model human ribosomopathies in Drosophila and find widespread apoptosis and cellular stress in the resulting animals. This is not caused by insufficient protein synthesis, as reasonably expected. Instead, ribosomal protein deficiency elicits proteotoxic stress, which we suggest is caused by the accumulation of misfolded proteins that overwhelm the protein degradation machinery. We find that dampening the integrated stress response4 or autophagy increases the harm inflicted by ribosomal protein deficiency, suggesting that these activities could be cytoprotective. Inhibition of TOR activity-which decreases ribosomal protein production, slows down protein synthesis and stimulates autophagy5-reduces proteotoxic stress in our ribosomopathy model. Interventions that stimulate autophagy, combined with means of boosting protein quality control, could form the basis of a therapeutic strategy for this class of diseases.

A Survey of Chemoreceptive Responses on Different Mosquito Appendages

Research on the functions of insect chemoreceptors have primarily focused on antennae (olfactory receptors) and mouthparts (gustatory receptors). However, chemoreceptive sensilla are also present on other appendages, such as the leg tarsi and the anterior wing margin, and their specific roles in chemoreception and mosquito behavior remain largely unknown. In this study, electrophysiological analyses in an electroantennogram recording format were performed on Aedes aegypti (L., Diptera: Culicidae) antennae, mouthparts, tarsi, and wings during exposure to a variety of insect repellent and attractant compounds. The results provide evidence that the tarsi and wings can sense chemicals in a gaseous form, and that the odors produce differing responses on different appendages. The most consistent and strongest response occurred when exposed to triethylamine (TEA). Antennae and mouthparts showed nearly identical responses pattern to all tested compounds, and their rank orders of effectiveness were similar to those of fore- and mid-leg tarsi. Hindleg tarsi only responded to TEA, indicating that the hind legs are not as chemoreceptive. Wings responded to a range of odorants, but with a different rank order and voltage amplitude. Insights gleaned into the function of these appendages in insect chemoreception are discussed.

Changes in the wing shape and size in Drosophila melanogaster treated with food grade titanium dioxide nanoparticles (E171) - A multigenerational study

Drosophila is among the most commonly used models for toxicity assessment of different types of nanoparticles. This study aims to examine the effects of a constant exposure to the low concentration of human food grade titanium dioxide nanoparticles (TiO₂ E171) on Drosophila melanogaster wing morphology over multiple generations. Subsequently, the Geometric Morphometrics Analysis was employed to examine possible changes in the wing shape and size of the treated flies. The treatment resulted in the diminishment but not a disruption in the sexual dimorphism in wings. Consequently, the female flies were clearly separated from the male flies by the differences in wing morphology as in the control group. A splitting by generations was overly similar within the control and the treatment, but it was slightly more pronounced in the treatment. However, the observed generational differences seemed mostly random between generations, irrespective of the treatment. Specifically, the treated groups displayed slightly higher splitting by generations in females than in males. Regardless of the generation, the results show a clear splitting by the differences in the wing shape between the treated flies and the flies from control. The mean value of centroid size, which refers to the wing size, of both female and male wings was smaller in the treatment when compared to the control. The overall effect of TiO₂ was to induce significant difference in Drosophila wing morphology but it did not alter the general wing morphology pattern. Therefore, the change in the wings occurred only within the normally allowed wing variation.

Radioprotective effect of chloropyllin, protoporphyrin-IX and bilirubin compared with amifostine® in Drosophila melanogaster

The identification of substances that prevent or minimize the detrimental effects of ionizing radiation is an essential undertaking. The aim of this paper was to evaluate and compare the radioprotective potential of chlorophyllin, protoporphyrin and bilirubin, with amifostine®, an US Food & Drug Administration approved radioprotector Using the somatic mutation and recombination assay in the Drosophila melanogaster wing, it was found that pretreatment (1-9 h) with any of the porphyrins or amifostine® alone, did not affect the larva-adult viability or the basal frequency of mutation. However, they were associated with significant reductions in frequency of somatic mutation and recombination compared with the gamma-irradiated (20 Gy) control as follows: bilirubin (69.3 %)> chlorophyllin (40.0 %)> protoporphyrin (39.0 %)> amifostine® (19.7 %). Bilirubin also caused a 16 % increase in larva-adult viability with 3 h of pretreatment respect to percentage induced in 20 Gy control group. Whilst amifostine® was associated with lower genetic damage after pre-treatment of 1 and 3 h, this did not attain significance. These findings suggest that the tested porphyrins may have some potential as radioprotectant agents.

Genetic Variation Influences Tolerance to a Neonicotinoid Insecticide in 3 Butterfly Species

Neonicotinoid pesticides harm nontarget insects, but their sublethal effects on butterflies are understudied. We exposed larvae of 3 butterfly species (Pieris rapae, Colias philodice, and Danaus plexippus) to low levels of the neonicotinoid imidacloprid in their host plants and followed individuals to adulthood. Imidacloprid altered adult body size, especially in female monarchs, but its effects varied across maternal families, highlighting the importance of considering genetic variation in ecotoxicological testing. Environ Toxicol Chem 2020;39:2228-2236. © 2020 SETAC.

Genes regulating wing patterning in Drosophila melanogaster show reduced expression under exposure of Daminozide, the fruit ripening retardant

In our previous study we demonstrated that the fruit ripening retardant Daminozide or Alar causes change in life history traits, distortion of adult wing structure, DNA damage in brain cells and mutagenic effects in fruit fly Drosophila melanogaster. As a continuation of the previous study the present work is designed to explore the metabolic modification of Daminozide following ingestion, the effects of Daminozide on the expression of genes which are pivotal for wing development and molecular interactions of Daminozide with those proteins involved in wing patterning. We demonstrated through reporter gene construct assay using X-gal staining method and transgenic Drosophila melanogaster stocks that the vestigial, wingless and decapentaplegic genes in wing imaginal disc from 3^rd instar larvae exhibited reduced expression when exposed to Daminozide in compare to control larvae. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) of those genes confirmed that exposure to Daminozide reduces the transcription level of those genes. In silico approach with molecular docking study revealed Daminozide may bind and interfere with the optimal functioning of expressed wing signaling proteins.

Evaluation of Culex quinquefasciatus wings asymmetry after exposure of larvae to sublethal concentration of ivermectin

The surviving insects submitted to chemical control have morphological alterations that impact on their mechanisms of resistance and their final development. Those changes are detected and measured using physical features related to symmetry, specifically named fluctuating asymmetry. This is detected when deviations from the perfect bilateral symmetry for specific morphological characteristic is influenced by genetics or environmental stress. Thus, in this paper we analyze the wing in adult of Culex quinquefasciatus (Diptera - Culicidae) after larvae exposure to ivermectin LC₅₀. Three hundred larvae of C. quinquefasciatus were exposed to ivermectin in 1.5 μg/L (LC₅₀) concentration during 30 min, and three hundred larvae were exposed to distilled pure water as control group. For fluctuating asymmetry, adult males and adult females were selected from each group (n = 83) from the untreated group and (n = 79) from treated group. Wings from adults of each group were mounted in glass microscope slides and coverslip in Canada's balsam and analyzed with a stereomicroscope with a video camera attached. The treatment effect on M_3 + 4 was marginally significant with higher asymmetry values in the control group. The data obtained here suggest the importance of future experiments to elucidate the mechanisms associated with FA. Moreover, according to the results obtained, it may be suggested that FA is present in females in ornaments, or secondary sexual characters, as an indicator of phenotypic quality of the partners.

Polyphenism of visual and chemical secondary sexually-selected wing traits in the butterfly Bicyclus anynana: How different is the intermediate phenotype?

Polyphenism is a type of phenotypic plasticity supposedly adaptive to drastic and recurrent changes in the environment such as seasonal alternation in temperate and tropical regions. The butterfly Bicyclus anynana shows polyphenism with well-described wet and dry seasonal forms in sub-Saharan Africa, displaying striking morphological, physiological and behavioural differences in response to higher or lower developmental temperatures. During the seasonal transition in the wild, the intermediate phenotype co-occurs with wet and dry phenotypes. In this study, we aimed to characterize the secondary sexually-selected wing traits of the intermediate form to infer its potential fitness compared to wet and dry phenotypes. Among the previously described wing morphological traits, we first showed that the area of the fifth eyespot on the ventral hindwing is the most discriminant trait to identify wet, dry and intermediate phenotypes in both sexes. Second, we characterized the intermediate form for two secondary sexually-selected wing traits: the area and UV reflectance of the dorsal forewing pupil and the composition of the male sex pheromone. We showed that values of these two traits are often between those of the wet and dry phenotypes. Third, we observed increasing male sex pheromone production in ageing dry and wet phenotypes. Our results contrast with previous reports of values for sexually-selected traits in wet and dry seasonal forms, which might be explained by differences in rearing conditions or sample size effects among studies. Wet, dry and intermediate phenotypes display redundant sexually dimorphic traits, including sexually-selected traits that can inform about their developmental temperature in sexual interactions.

Fluctuating asymmetry and exposure to pyrethroid insecticides in Triatoma infestans populations in northeastern Argentina

Fluctuating asymmetry (FA), a phenotypic marker used as indicator of developmental stress or instability, is sometimes associated with insecticide application and resistance. Here we investigated the occurrence and amount of wing size and wing shape FA in Triatoma infestans females and males collected before and 4 months after a community-wide pyrethroid spraying campaign in a well-defined rural area of Pampa del Indio, Argentina. Moderate levels of pyrethroid resistance were previously confirmed for this area, and postspraying house infestation was mainly attributed to this condition. In the absence of insecticide-based selective pressures over the previous 12 years, we hypothesized that 1- if postspraying triatomines were mostly survivors to insecticide spraying (pyrethroid resistant), they would have higher levels of FA than prespraying triatomines. 2- if postspraying triatomines have a selective advantage, they would have lower FA levels than their prespraying counterparts, whereas if postspraying infestation was positively associated with immigrants not exposed to the insecticide, prespraying and postspraying triatomines would display similar FA levels. For 243 adult T. infestans collected at identified sites before insecticide spraying and 112 collected 4 months postspraying, wing size and wing shape asymmetry was estimated from landmark configurations of left and right sides of each individual. At population level, wing size and shape FA significantly decreased in both females and males after spraying. Males displayed greater wing size and shape FA than females. However, at a single peridomestic site that was persistently infested after spraying, FA declined similarly in females whereas the reverse pattern occurred in males. Our results suggest differential survival of adults with more symmetric wings. This pattern may be related to a selective advantage of survivors to insecticide spraying, which may be mediated or not by their pyrethroid-resistant status or to lower triatomine densities after insecticide spraying and the concomitant increase in feeding success.

Different radiation dose rate as radioprotection and the cross effect with chromium using in vivo somatic cells of Drosophila

Ionizing radiation plays a key role in the adaptation of an individual organism to environmental pollution, at the same time, it has biological effects that depend on radiation intensity or dose rate (DR). Although the effect of DR has been studied in vitro, the phenomenon known as the inverse effect of DR, which indicates as it decreases that the induction of damage is greater, has not been widely studied in vivo. The present study is aimed to test 0.5 and 1 Gy in somatic cells of the wing of D. melanogaster, administered at 5.4 or 34.3 Gy/h and from 0.037 to 0.3 mM of CrO₃ as conditioning treatment. No changes were found in larva-to-adult viability. A protective as well as a cross effect of pre-exposure to different DR and CrO₃ concentrations against genetic damage induced by 20 Gy or 1 mM CrO₃ was evident.

Evidence that the radioprotector effect of ascorbic acid depends on the radiation dose rate

Many studies have revealed that ascorbic acid (Aa) acts as a powerful inhibitor of genetic damage. The objetive of the present study was to evaluate the radioprotector effect of Aa at two diferent radiation dose rates. The somatic mutation and recombination test in Drosophila melanogaster was used. 48 h larvae were treated for 24 h with 25, 50 and 100 mM of Aa. After pretreatment, larvae were irradiated with 20 Gy of gamma rays administered at 36 or 960 Gy/h. Toxicity, development rate and frequency of mutant spots were recorded. Results provide evidence of a radioprotective effect for all tested concentrations of Aa only when 20 Gy were delivered at 36 Gy/h and only with 25 mM using the 960 Gy/h. To consider the use of Aa as radioprotector or therapeutic agent, it is necessary to know its potential under different situations to avoid unwanted injuries.

Antimutagenic action of the live yeast can be transmitted to the offspring of Drosophila melanogaster. A genetic study using the wing spot assay

The present study evaluates whether the protective effect of live yeast (LY) against direct and indirect mutagenic agents, persists in the offspring from individuals fed with LY. The wing-spot test in Drosophila was used; four different mates were performed: a) neither females nor males were fed with LY-enriched food (NLYxNLY); b) only females were fed (LYxNLY); c) males were fed (NLYxLY) or d) both progenitors were fed (LYxLY). Results confirm that LY strongly stimulates fecundity in females but not in males and provides strength to the egg for survive. A greater reduction in mutation rate was observed when females were feed, in the following relationship: LYxNLY>LYxLY>NLYxLY. No protection was found against action in any of the promutagens tested. Results suggest that LY has a very powerful antimutagenic action, predominantly against the action of ionizing radiation and Chromium trioxide that can be transmitted mainly through the female.

Trans-generational transmission of altered phenotype resulting from flubendiamide-induced changes in apoptosis in larval imaginal discs of Drosophila melanogaster

The eye and wing morphology of Drosophila melanogaster maintain unique, stable pattern of genesis from larval eye and wing imaginal discs. Increased apoptosis in cells of eye and wing discs was found to be associated with flubendiamide (fluoride containing insecticide) exposure (at the range 0.25-10μg/mL) in D. melanogaster larvae. The chemical fed larvae on attaining adulthood revealed alterations in morphology and symmetry of their compound eyes and wings through scanning electron microscopy. Nearly 40% and 30% of flies (P generation) demonstrated alterations in eyes and wings respectively. Transmission electron microscopic study (at the range 1-20μg/mL) also established variation in the rhabdomere and pigment cell orientation as well as in the shape of the ommatidium. Subsequent SEM study with F₁ and F₂ generation flies also revealed structural variation in eye and wing. Decrease in percentage of altered eye and wing phenotype was noted in subsequent generations (P> F₁>F₂). Thus, the diamide insecticide, flubendiamide, expected to be environmentally safe at sub-lethal concentrations was found to increase apoptosis in larvae and thereby cause morphological alteration in the adult D. melanogaster. This study further demonstrated trans-generational transmission of altered phenotype in three subsequent generations of a non-target insect model, D. melanogaster.

Forewing structure of the solitary bee Osmia bicornis developing on heavy metal pollution gradient

Wild bees in natural conditions can develop under various environmental stressors. Heavy metal pollution of the environment is one of the most widely studied stressors in insects, yet its effect is poorly described in bees. We have measured how pollution of the environment along a zinc, cadmium and lead contamination gradient in Poland affects bee development, using red mason bees (Osmia bicornis) as a model and their forewing asymmetry measures to assess possible developmental instabilities. We have also described wing asymmetry measures in the red mason bee-an important managed pollinator species-for the first time. The development of bee larvae in a contaminated environment did not affect forewing asymmetry measures, but it did lead to a negative correlation of wing size with contamination in females. Bees also showed a clear change in their asymmetry measures between various seasons, suggesting other, unknown environmental factors affecting wing asymmetry more than pollution. Sexes were found to have different forewing shape and size, larger females having larger forewings than the smaller males. The direction of size asymmetry was in favour of the left side in both sexes and also shape differences between the left and right wings showed similar tendencies in males and females. The levels of forewing shape and size asymmetry were smaller in females, making them the more symmetrical sex.

Trouble on takeoff: Crude oil on feathers reduces escape performance of shorebirds

The ability to takeoff quickly and accelerate away from predators is crucial to bird survival. Crude oil can disrupt the fine structure and function of feathers, and here we tested for the first time how small amounts of oil on the trailing edges of the wings and tail of Western sandpipers (Calidris mauri) affected takeoff flight performance. In oiled birds, the distance travelled during the first 0.4s after takeoff was reduced by 29%, and takeoff angle was decreased by 10° compared to unoiled birds. Three-axis accelerometry indicated that oiled sandpipers produced less mechanical power output per wingbeat during the initial phase of flight. Slower and lower takeoff would make oiled birds more likely to be targeted and captured by predators, reducing survival and facilitating the exposure of predators to oil. Whereas the direct mortality of heavily-oiled birds is often obvious and can be quantified, our results show that there are significant sub-lethal effects of small amounts crude oil on feathers, which must be considered in natural resource injury assessments for birds.

Antimutagenic evaluation of traditional medicinal plants from South America Peumus boldus and Cryptocarya alba using Drosophila melanogaster

Peumus boldus Mol. ("Boldo") and Cryptocarya alba Mol. Looser ("Peumo") are medicinal shrubs with wide geographical distribution in South America. Their leaves and fruits are commonly used in traditional medicine because they exhibit natural medicinal properties for treatment of liver disorders and rheumatism. However, there are no apparent data regarding potential protective effects on cellular genetic components. In order to examine potential mutagenic and/or antimutagenic effects of these medicinal plants, the Drosophila melanogaster (D. melanogaster) wing-spot test was employed. This assay detects a wide range of mutational events, including point mutations, deletions, certain types of chromosomal aberrations (nondisjunction), and mitotic recombination. Qualitative and quantitative analyses of phenolic and anthocyanin compounds were carried out using biochemical and high-performance liquid chromatography methodologies. In addition, the antioxidant capacity of P. boldus and C. alba leaf extracts was also analyzed. P. boldus and C. alba extracts did not induce significant mutagenic effects in the D. melanogaster model. However, simultaneous treatment of extracts concurrently with the mutagen ethyl methane sulphonate showed a decrease of mutant spots in somatic cells of D. melanogaster, indicating desmutagenic effects in this in vivo model. Flavonoids and anthocyanins were detected predominantly in the extracts, and these compounds exerted significant antioxidant capacity. The observed antimutagenic effects may be related to the presence of phytochemicals with high antioxidant capacity, such as flavonoids and antohocyanins, in the extracts.

Ecdysone signaling underlies the pea aphid transgenerational wing polyphenism

The wing polyphenism of pea aphids is a compelling laboratory model with which to study the molecular mechanisms underlying phenotypic plasticity. In this polyphenism, environmental stressors such as high aphid density cause asexual, viviparous adult female aphids to alter the developmental fate of their embryos from wingless to winged morphs. This polyphenism is transgenerational, in that the pea aphid mother experiences the environmental signals, but it is her offspring that are affected. Previous research suggested that the steroid hormone ecdysone may play a role in this polyphenism. Here, we analyzed ecdysone-related gene expression patterns and found that they were consistent with a down-regulation of the ecdysone pathway being involved in the production of winged offspring. We therefore predicted that reduced ecdysone signaling would result in more winged offspring. Experimental injections of ecdysone or its analog resulted in a decreased production of winged offspring. Conversely, interfering with ecdysone signaling using an ecdysone receptor antagonist or knocking down the ecdysone receptor gene with RNAi resulted in an increased production of winged offspring. Our results are therefore consistent with the idea that ecdysone plays a causative role in the regulation of the proportion of winged offspring produced in response to crowding in this polyphenism. Our results also show that an environmentally regulated maternal hormone can mediate phenotype production in the next generation, as well as provide significant insight into the molecular mechanisms underlying the functioning of transgenerational phenotypic plasticity.

Copper oxide nanoparticles and copper sulphate act as antigenotoxic agents in drosophila melanogaster

The biological reactivity of metal and metal oxide nanomaterials is attributed to their redox properties, which would explain their pro- or anti-cancer properties depending on exposure circumstances. In this sense, copper oxide nanoparticles (CuONP) have been proposed as a potential anti-tumoral agent. The aim of this study was to assess if CuONP can exert antigenotoxic effects using Drosophila melanogaster as an in vivo model. Genotoxicity was induced by two well-known genotoxic compounds, namely potassium dichromate (PD) and ethyl methanesulfonate (EMS). The wing-spot assay and the comet assay were used as biomarkers of genotoxic effects. In addition, changes in the expression of Ogg1 and Sod genes were determined. The effects of CuONP cotreatment were compared with those induced by copper sulfate (CS), an agent releasing copper ions. Using the wing-spot assay, CuONP and CS were not able to reduce the genotoxic effects of EMS exposure, but had the ability to decrease the effects induced by PD, reducing the frequency of mutant twin-spots that arise from mitotic recombination. In addition, CuONP and CS were able to reduce the DNA damage induced by PD as determined by the comet assay. In general, similar qualitative antigenotoxic effects were obtained with both copper compounds. The antigenotoxic effects of environmentally relevant and non-toxic doses of CuONP and CS may be explained by their ability to partially restore the expression levels of the repair gene Ogg1 and the antioxidant gene Cu,ZnSod, both of which are inhibited by PD treatment. Environ. Mol. Mutagen. 58:46-55, 2017. © 2016 Wiley Periodicals, Inc.

Assessment of the mutagenic, recombinogenic and carcinogenic potential of fipronil insecticide in somatic cells of Drosophila melanogaster

Fipronil (FP) is an insecticide that belongs to the phenylpyrazole chemical family and is used to control pests by blocking GABA receptor at the entrance channel of the chlorine neurons. The aim of this study was to evaluate the mutagenic, recombinogenic and carcinogenic potential of FP. The mutagenic and recombinogenic effects were evaluated using the somatic mutation and recombination test (SMART) on wing cells of Drosophila melanogaster. Third instar larvae from standard (ST) and high bioactivation (HB) crosses were treated with different concentrations of FP (0.3, 0.7, 1.5 or 3.0 × 10^-5 mM). The results showed mutagenic effects at all concentrations tested in the HB cross; and all concentrations tested in the ST cross, except at concentration of 0.7 × 10^-5 mM. The carcinogenic effect of FP was assayed through the test for detection of epithelial tumor (warts) in D. melanogaster. Third instar larvae from wts/TM3 virgin females mated to mwh/mwh males were treated with different concentrations of FP (0.3, 0.7, 1.5 or 3.0 × 10^-5 mM). All these concentrations induced a statistically significant increase in tumor frequency. In conclusion, FP proved to be mutagenic, recombinogenic and carcinogenic in somatic cells of D. melanogaster.

Study on the relationship of genotoxic and oxidative potential of a new mixed chelate copper antitumoral drug, Casiopeina II-gly (Cas II-gly) in Drosophila melanogaster

The present study evaluates the superoxide dismutase (SOD) and catalase (CAT) activities in a wild strain of Drosophila melanogaster and the genotoxic potential induced by Cas II-gly (a new antineoplastic drug) using the somatic mutation and recombination test. Larvae 48h old were treated with Cas II-gly in a range of 0-1.5mM and aliquot were taken every 24h to have individuals treated for 24, 48, 72h and adulthood as well. A dose-dependent toxicity and a significant increase in SOD and CAT activities were found after a 24 and 48h treatment with 0.5-1.5mM concentrations. The comparison of the effect in enzymes with mutation indicated a positive correlation with increased genetic damage, after 24 and 48h of exposure for all concentrations tested. The addition of the genetic damage induced in each exposure time showed a significant effect, but only the small single spots had a concentration-related increase.

Long-Chain Omega-3 Polyunsaturated Fatty Acids Have Developmental Effects on the Crop Pest, the Cabbage White Butterfly Pieris rapae

Nutritional enhancement of crops using genetic engineering can potentially affect herbivorous pests. Recently, oilseed crops have been genetically engineered to produce the long-chain omega-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) at levels similar to that found in fish oil; to provide a more sustainable source of these compounds than is currently available from wild fish capture. We examined some of the growth and development impacts of adding EPA and DHA to an artificial diet of Pieris rapae, a common pest of Brassicaceae plants. We replaced 1% canola oil with EPA: DHA (11:7 ratio) in larval diets, and examined morphological traits and growth of larvae and ensuing adults across 5 dietary treatments. Diets containing increasing amounts of EPA and DHA did not affect developmental phenology, larval or pupal weight, food consumption, nor larval mortality. However, the addition of EPA and DHA in larval diets resulted in progressively heavier adults (F _{4, 108} = 6.78; p = 0.011), with smaller wings (p < 0.05) and a higher frequency of wing deformities (R = 0.988; p = 0.001). We conclude that the presence of EPA and DHA in diets of larval P. rapae may alter adult mass and wing morphology; therefore, further research on the environmental impacts of EPA and DHA production on terrestrial biota is advisable.

Wings as a new route of exposure to pesticides in the honey bee

In pesticide risk assessment, estimating the routes and levels of exposure is critical. For honey bees subjected to pesticide spray, toxicity is assessed by thorax contact to account for all possible contact exposures. In the present study, the authors tested 6 active substances with different hydrophobicity. For the first time, the authors demonstrated that it is possible to induce mortality by pesticide contact with only the wings of the honey bee. The toxicities induced by contact with the wings and thorax were similar, with the wing median lethal dose (LD50) being 0.99 to 2.23 times higher than that of the thorax. This finding demonstrates that the wings represent a relevant route of exposure in the honey bee. In a second approach, the authors estimated the air volume displaced by the wings during 1 beating cycle to be 0.51 ± 0.03 cm(3), which corresponds to a volume of 116.8 ± 5.8 cm(3)  s(-1) at a wing beat frequency of 230 Hz. The authors then tested realistic scenarios of exposure for bees flying through a pesticide cloud at different concentrations. In the worst-case scenario, the dose accumulated during the flight reached 525 ng bee(-1)  s(-1). These results show that the procedure used to assess the risk posed by contact with pesticides could be improved by accounting for wing exposure.

Pyrethroids and Nectar Toxins Have Subtle Effects on the Motor Function, Grooming and Wing Fanning Behaviour of Honeybees (Apis mellifera)

Sodium channels, found ubiquitously in animal muscle cells and neurons, are one of the main target sites of many naturally-occurring, insecticidal plant compounds and agricultural pesticides. Pyrethroids, derived from compounds found only in the Asteraceae, are particularly toxic to insects and have been successfully used as pesticides including on flowering crops that are visited by pollinators. Pyrethrins, from which they were derived, occur naturally in the nectar of some flowering plant species. We know relatively little about how such compounds--i.e., compounds that target sodium channels--influence pollinators at low or sub-lethal doses. Here, we exposed individual adult forager honeybees to several compounds that bind to sodium channels to identify whether these compounds affect motor function. Using an assay previously developed to identify the effect of drugs and toxins on individual bees, we investigated how acute exposure to 10 ng doses (1 ppm) of the pyrethroid insecticides (cyfluthrin, tau-fluvalinate, allethrin and permethrin) and the nectar toxins (aconitine and grayanotoxin I) affected honeybee locomotion, grooming and wing fanning behaviour. Bees exposed to these compounds spent more time upside down and fanning their wings. They also had longer bouts of standing still. Bees exposed to the nectar toxin, aconitine, and the pyrethroid, allethrin, also spent less time grooming their antennae. We also found that the concentration of the nectar toxin, grayanotoxin I (GTX), fed to bees affected the time spent upside down (i.e., failure to perform the righting reflex). Our data show that low doses of pyrethroids and other nectar toxins that target sodium channels mainly influence motor function through their effect on the righting reflex of adult worker honeybees.

Genotoxic and Antigenotoxic Assessment of Chios Mastic Oil by the In Vitro Micronucleus Test on Human Lymphocytes and the In Vivo Wing Somatic Test on Drosophila

Chios mastic oil (CMO), the essential oil derived from Pistacia lentiscus (L.) var. chia (Duham), has generated considerable interest because of its antimicrobial, anticancer, antioxidant and other beneficial properties. In the present study, the potential genotoxic activity of CMO as well as its antigenotoxic properties against the mutagenic agent mitomycin-C (MMC) were evaluated by employing the in vitro Cytokinesis Block MicroNucleus (CBMN) assay and the in vivo Somatic Mutation And Recombination Test (SMART). In the in vitro experiments, lymphocytes were treated with 0.01, 0.05 and 0.10% (v/v) of CMO with or without 0.05 μg/ml MMC, while in the in vivo assay Drosophila larvae were fed with 0.05, 0.10, 0.50 and 1.00% (v/v) of CMO with or without 2.50 μg/ml MMC. CMO did not significantly increase the frequency of micronuclei (MN) or total wing spots, indicating lack of mutagenic or recombinogenic activity. However, the in vitro analysis suggested cytotoxic activity of CMO. The simultaneous administration of MMC with CMO did not alter considerably the frequencies of MMC-induced MN and wing spots showing that CMO doesn’t exert antigenotoxic or antirecombinogenic action. Therefore, CMO could be considered as a safe product in terms of genotoxic potential. Even though it could not afford any protection against DNA damage, at least under our experimental conditions, its cytotoxic potential could be of interest.

Metamorphosis enhances the effects of metal exposure on the mayfly, Centroptilum triangulifer

The response of larval aquatic insects to stressors such as metals is used to assess the ecological condition of streams worldwide. However, nearly all larval insects metamorphose from aquatic larvae to winged adults, and recent surveys indicate that adults may be a more sensitive indicator of stream metal toxicity than larvae. One hypothesis to explain this pattern is that insects exposed to elevated metal in their larval stages have a reduced ability to successfully complete metamorphosis. To test this hypothesis we exposed late-instar larvae of the mayfly, Centroptilum triangulifer, to an aqueous Zn gradient (32-476 μg/L) in the laboratory. After 6 days of exposure, when metamorphosis began, larval survival was unaffected by zinc. However, Zn reduced wingpad development at concentrations above 139 μg/L. In contrast, emergence of subimagos and imagos tended to decline with any increase in Zn. At Zn concentrations below 105 μg/L (hardness-adjusted aquatic life criterion), survival between the wingpad and subimago stages declined 5-fold across the Zn gradient. These results support the hypothesis that metamorphosis may be a survival bottleneck, particularly in contaminated streams. Thus, death during metamorphosis may be a key mechanism explaining how stream metal contamination can impact terrestrial communities by reducing aquatic insect emergence.

[Variability patterns of nest construction, physiological state, and morphometric traits in honey bee]

High variability of cells size is used selectively for reproduction of working bees and drones. A decrease in both distance between cells and cells size themselves causes similar effects to body mass and morphometric traits of developing individuals. Adaptation of honey bees to living in shelters has led to their becoming tolerant to hypoxia. Improvement of ethological and physiological mechanisms of thermal regulation is associated with limitation of ecological valence and acquiring of stenothermic features by breed. Optimal thermal conditions for breed are limited by the interval 33-34.5 degrees C. Deviations of temperature by 3-4 degrees C beyond this range have minimum lethal effect at embryonic stage of development and medium effect at the stage of pre-pupa and pupa. Developing at the low bound of the vital range leads to increasing, while developing at the upper bound--to decreasing of body mass, mandibular and hypopharyngeal glands, as well as other organs, which, later, affects the variability of these traits during the adult stage of development. Eliminative and teratogenic efficiency of ecological factors that affect a breed is most often manifested in underdevelopment of wings. However, their size (in case of wing laminas formation). is characterized by relatively low variability and size-dependent asymmetry. Asymmetry variability of wings and other pair organs is expressed through realignment of size excess from right- to left-side one with respect to their increase. Selective elimination by those traits whose emerging probability increases as developmental conditions deviate from the optimal ones promotes restrictions on individual variability. Physiological mechanisms that facilitate adaptability enhancement under conditions of increasing anthropogenic contamination of eivironment and trophic substrates consumed by honey bees, arrear to be toxicants accumulation in rectum and crops' ability to absorb contaminants from nectar in course of its processing to honey.

Ecdysteroid-induced programmed cell death is essential for sex-specific wing degeneration of the wingless-female winter moth

The winter moth, Nyssiodes lefuarius, has a unique life history in that adults appear during early spring after a long pupal diapause from summer to winter. The moth exhibits striking sexual dimorphism in wing form; males have functional wings of normal size, whereas females lack wings. We previously found that cell death of the pupal epithelium of females appears to display condensed chromatin within phagocytes. To provide additional detailed data for interpreting the role of cell death, we performed light microscopy, transmission electron microscopy, and TUNEL assay. We consequently detected two modes of cell death, i.e., dying cells showed both DNA fragmentation derived from epithelial nuclei and autophagic vacuole formation. To elucidate the switching mechanism of sex-specific wing degeneration in females of N. lefuarius, we tested the effects of the steroid hormone 20-hydroxyecdysone (20E) on pupal diapause termination and wing morphogenesis in both sexes. When 20E (5.4 µg) was injected into both sexes within 2 days of pupation, wing degeneration started 4 days after 20E injection in females, whereas wing morphogenesis and scale formation started 6 days after 20E injection in males. We discuss two important findings: (1) degeneration of the pupal wing epithelium of females was not only due to apoptosis and phagocytotic activation but also to autophagy and epithelial cell shrinkage; and (2) 20E terminated the summer diapause of pupae, and triggered selective programmed cell death only of the female-pupal wing epithelium in the wingless female winter moth.

Transgenic Anopheles gambiae expressing an antimalarial peptide suffer no significant fitness cost

Mosquito-borne diseases present some of the greatest health challenges faced by the world today. In many cases, existing control measures are compromised by insecticide resistance, pathogen tolerance to drugs and the lack of effective vaccines. In light of these difficulties, new genetic tools for disease control programmes, based on the deployment of genetically modified mosquitoes, are seen as having great promise. Transgenic strains may be used to control disease transmission either by suppressing vector populations or by replacing susceptible with refractory genotypes. In practice, the fitness of the transgenic strain relative to natural mosquitoes will be a critical determinant of success. We previously described a transgenic strain of Anopheles gambiae expressing the Vida3 peptide into the female midgut following a blood-meal, which exhibited significant protection against malaria parasites. Here, we investigated the fitness of this strain relative to non-transgenic controls through comparisons of various life history traits. Experiments were designed, as far as possible, to equalize genetic backgrounds and heterogeneity such that fitness comparisons focussed on the presence and expression of the transgene cassette. We also employed reciprocal crosses to identify any fitness disturbance associated with inheritance of the transgene from either the male or female parent. We found no evidence that the presence or expression of the effector transgene or associated fluorescence markers caused any significant fitness cost in relation to larval mortality, pupal sex ratio, fecundity, hatch rate or longevity of blood-fed females. In fact, fecundity was increased in transgenic strains. We did, however, observe some fitness disturbances associated with the route of inheritance of the transgene. Maternal inheritance delayed male pupation whilst paternal inheritance increased adult longevity for both males and unfed females. Overall, in comparison to controls, there was no evidence of significant fitness costs associated with the presence or expression of transgenes in this strain.

Absence of mutagenic and recombinagenic activity of multi-walled carbon nanotubes in the Drosophila wing-spot test and Allium cepa test

In order to assess the safety of the carbon nanotubes to human health and the environment, we investigated the potential toxicity and ability of multi-walled carbon nanotubes (NT), to induce DNA damage by employing the Allium cepa genotoxicity/mutagenicity test and the Somatic Mutation and Recombination Test (SMART) in the fruitfly, Drosophila melanogaster. The results demonstrated that NT did not significantly induce genotoxic or mutagenic effects in the Allium cepa test. All concentrations evaluated in the SMART assay showed survival rates higher than 90percent, indicating the absence of chronic toxicity for NT. Furthermore, the various treatments showed no significant increase in the NT mutation and recombination frequencies in mwh/flr(3) genotype compared to respective negative controls, demonstrating the absence of DNA damage caused by NT.

Genotoxic, antigenotoxic and phytochemical assessment of Terminalia actinophylla ethanolic extract

Terminalia actinophylla has been used for anti-diarrheic and haemostatic purposes in Brazil. The fly spot data obtained after exposure of marker-heterozygous Drosophila melanogaster larvae to T. actinophylla ethanolic extract (TAE) in the standard (ST) and high bioactivation (HB) crosses revealed that TAE did not induce any statistically significant increment in any spot categories. Differences between the two crosses are related to cytochrome P450 (CYPs) levels. In this sense, our data pointed out the absence of TAE-direct and indirect mutagenic and recombinagenic action in the Somatic Mutation and Recombination Test (SMART). When the anti-genotoxicity of TAE was analyzed, neither mitomycin C (MMC) nor ethylmethanesulfonate (EMS) genotoxicity was modified by the post-exposure to TAE, which suggests that TAE has no effect on the mechanisms involved in the processing of the lesions induced by both genotoxins. In the mwh/flr(3) genotype, co-treatment with TAE may lead to a significant protection against the genotoxicity of MMC and a weak but significant effect in the toxic genetic action of EMS. The overall findings suggested that the favorable modulations by TAE could be, at least in part, due to its antioxidative potential.

Detection of transfluthrin and metofluthrin genotoxicity in the ST cross of the Drosophila Wing Spot Test

In this study, different concentrations of transfluthrin and metofluthrin have been assayed for genotoxicity by using the Wing Spot Test on Drosophila melanogaster. Standard cross was used in the experiment. Third-instar larvae that were trans-heterozygous for the two genetic markers mwh and flr(3) were treated at different concentrations (0.0103mgmL(-1), 0.103mgmL(-1) for transfluthrin and 6μgmL(-1), 60μgmL(-1) for metofluthrin) of the test compounds. Feeding ended with pupation of the surviving larvae and the genetic changes induced in somatic cells of the wing's imaginal discs lead to the formation of mutant clones on the wing blade. Results indicated that two experimental concentrations of transfluthrin and 60μgmL(-1) metofluthrin showed mutagenic and recombinogenic effects in both the marker-heterozygous (MH) flies and the balancer-heterozygous (BH) flies.

Evaluation of the genotoxic and antigenotoxic effects of Chios mastic water by the in vitro micronucleus test on human lymphocytes and the in vivo wing somatic test on Drosophila

Chios mastic gum, a plant-derived product obtained by the Mediterranean bush Pistacia lentiscus (L.) var. chia (Duham), has generated considerable interest because of its antimicrobial, anticancer, antioxidant and other beneficial properties. Its aqueous extract, called Chios mastic water (CMW), contains the authentic mastic scent and all the water soluble components of mastic. In the present study, the potential genotoxic activity of CMW, as well as its antigenotoxic properties against the mutagenic agent mitomycin-C (MMC), was evaluated by employing the in vitro Cytokinesis Block MicroNucleus (CBMN) assay and the in vivo Somatic Mutation And Recombination Test (SMART). In the former assay, lymphocytes were treated with 1, 2 and 5% (v/v) of CMW with or without MMC at concentrations 0.05 and 0.50 µg/ml. No significant micronucleus induction was observed by CMW, while co-treatment with MMC led to a decrease of the MMC-induced micronuclei, which ranged between 22.8 and 44.7%. For SMART, larvae were treated with 50 and 100% (v/v) CMW with or without MMC at concentrations 1.00, 2.50 and 5.00 µg/ml. It was shown that CMW alone did not modify the spontaneous frequencies of spots indicating lack of genotoxic activity. Τhe simultaneous administration of MMC with 100% CMW led to considerable alterations of the frequencies of MMC-induced wing spots with the total mutant clones showing reduction between 53.5 and 74.4%. Our data clearly show a protective role of CMW against the MMC-induced genotoxicity and further research on the beneficial properties of this product is suggested.

Sodium copper chlorophyllin (SCC) induces genetic damage in postmeiotic and somatic wing cells of Drosophila melanogaster

There is no apparent evidence to indicate that sodium copper chlorophyllin (SCC) is mutagenic. The aim of the present study was thus to determine the mutagenic effect of SCC, in postmeiotic germ cells of the adult male Drosophila. This investigation was based on the ability to examine whether SCC induced sex-linked recessive lethal mutations (SLRL), as well as the somatic mutation and recombination test (SMART). Four different SCC concentrations were used: 0, 45, 69, 80, and 100 mM. For SLRL, two broods were generated to test sperm and primarily spermatids. Results showed a significant frequency of recessive lethal mutations compared with control sperm cells with SCC at 69, 80, and 100 mM. In contrast, the frequency of somatic mutations rose by 0.21 only with 100 mM of SCC. These findings provide evidence that SCC is a weak mutagen in both cell lines. The differential response may be attributed to repair mechanisms that are active in somatic cells but almost absent in germ cells.

The physiological effect of ingested β-N-methylamino-L-alanine on a glutamatergic synapse in an in vivo preparation

The neurotoxin, BMAA (β-N-methylamino-L-alanine), may be a risk factor for amyotrophic lateral sclerosis (ALS), Parkinson's (PD) and Alzheimer's (AD) disease. In vivo experiments have demonstrated that BMAA can cause a number of motor dysfunctions if ingested or injected, and in vitro experiments show that this toxin binds to glutamate receptors with deleterious results. Also, BMAA exists in the human food chain worldwide, and has been detected in the brains of ALS and AD patients. This paper offers the first demonstration by intracellular recording of the effect of ingested BMAA on the postsynaptic response of an identified glutamatergic cell in a living, undissected organism (Drosophila melanogaster), and correlates these observations with the specific motor dysfunctions that result from ingestion. The results suggest that BMAA acts as a glutamate agonist, causing NMDA receptor channels to remain open for prolonged periods of time, thereby damaging the cell by excitotoxicity. The effect on the postsynaptic response became apparent days before the function of the postsynaptic cell (wing beat) became affected. Severely depolarized cells were able to fully recover with the removal of BMAA from the food source, suggesting that blocking BMAA binding in the brain might be a good treatment strategy.

Evaluation of potential genotoxicity of five food dyes using the somatic mutation and recombination test

In this study, different concentrations of five food dyes (amaranth, patent blue, carminic acid, indigotine and erythrosine) have been evaluated for genotoxicity in the Somatic Mutation and Recombination Test (SMART) of Drosophila melanogaster. Standard cross was used in the experiment. Larvae including two linked recessive wing hair mutations were chronically fed at different concentrations of the test compounds in standard Drosophila Instant Medium. Feeding ended with pupation of the surviving larvae. Wings of the emerging adult flies were scored for the presence of spots of mutant cells which can result from either somatic mutation or somatic recombination. For the evaluation of genotoxic effects, the frequencies of spots per wing in the treated series were compared to the control group, which was distilled water. The present study shows that carminic acid and indigotine demonstrated negative results while erythrosine demonstrated inconclusive results. In addition 25 mg mL(-1) concentration of patent blue and 12.5, 25 and 50 mg mL(-1) concentrations of amaranth demonstrated positive results in the SMART.

Plant terpenoids: acute toxicities and effects on flight motor activity and wing beat frequency in the blow fly Phaenicia sericata

We evaluated the acute toxicities and the physiological effects of plant monoterpenoids (eugenol, pulegone, citronellal and alpha-terpineol) and neuroactive insecticides (malathion, dieldrin and RH3421) on flight muscle impulses (FMI) and wing beat signals (WBS) of the blow fly (Phaenicia sericata). Topically-applied eugenol, pulegone, citronellal, and alpha-terpineol produced neurotoxic symptoms, but were less toxic than malathion, dieldrin, or RH3421. Topical application of eugenol, pulegone, and citronellal reduced spike amplitude in one of the two banks of blow fly dorsolongitudinal flight muscles within 6-8 min, but with citronellal, the amplitude of FMIs reverted to a normal pattern within 1 hr. In contrast to pulegone and citronellal, where impulse frequency remained relatively constant, eugenol caused a gradual increase, then a decline in the frequency of spikes in each muscle bank. Wing beating was blocked permanently within 6-7 min of administering pulegone or citronellal and within 16 mins with eugenol. alpha-Terpineol-treated blow flies could not beat their wings despite normal FMI patterns. The actions of these monoterpenoids on blow fly flight motor patterns are discussed and compared with those of dieldrin, malathion, RH3421, and a variety of other neuroactive substances we have previously investigated in this system. Eugenol, pulegone and citronellal readily penetrate blow fly cuticle and interfere with flight muscle and/or central nervous function. Although there were differences in the effects of these compounds, they mainly depressed flight-associated responses, and acted similarly to compounds that block sodium channels and facilitate GABA action.

Identification of a classical bipartite nuclear localization signal in the Drosophila TEA/ATTS protein scalloped

Drosophila melanogaster wing development has been shown to rely on the activity of a complex of two proteins, Scalloped (Sd) and Vestigial (Vg). Within this complex, Sd is known to provide DNA binding though its TEA/ATTS domain, while Vg modulates this binding and provides transcriptional activation through N- and C-terminal activation domains. There is also evidence that Sd is required for the nuclear translocation of Vg. Indeed, a candidate sequence which shows consensus to the bipartite family of nuclear localization signals (NLSs) has been identified within Sd previously, though it is not known if it is functional, or if additional unpredicted signals that mediate nuclear transport exist within the protein. By expressing various enhanced green fluorescent protein (eGFP) tagged constructs within Drosophila S2 cells, we demonstrate that this NLS is indeed functional and necessary for the proper nuclear localization of Sd. Additionally, the region containing the NLS is critical for the wildtype function of ectopically expressed Sd, in the context of wing development. Using site-directed mutagenesis, we have identified a group of five amino acids within this NLS which is critical for its function, as well as another group of two which is of lesser importance. Together with data that suggests that this sequence mediates interactions with Importin-α3, we conclude that the identified NLS is likely a classical bipartite signal. Further dissection of Sd has also revealed that a large portion of the C-terminal domain of the protein is required its proper nuclear localization. Finally, a Leptomycin B (LB) sensitive signal which appears to facilitate nuclear export is identified, raising the possibility that Sd also contains a nuclear export signal (NES).

Physiological characterization of the cold-shock-induced humoral factor for wing color-pattern changes in butterflies

Butterfly wing color patterns can be modified by the application of temperature shock to pupae immediately after pupation, which has been attributed to a cold-shock-induced humoral factor called cold-shock hormone (CSH). Here, we physiologically characterized CSH and pharmacological action of tungstate, using a nymphalid butterfly Junonia orithya. We first showed that the precise patterns of modification were dependent on the time-point of the cold-shock treatment after pupation, and confirmed that the modification properties induced in a cold-shocked pupa were able to be transferred to another pupa in a parabiosis experiment. Cold-shock application after removal of the head and prothorax together still produced modified wings, excluding major involvement of the brain-retrocerebral neuroendocrine complex. Furthermore, tungstate injection induced modifications even in individuals whose head and prothorax were removed. Importantly, transplantation of tracheae isolated from cold-shocked pupae induced modifications in the recipient wings. We identified a chemical peak in hemolymph of the cold-shocked individuals using HPLC, which corresponded to dopamine, and demonstrated that dopamine and its related biogenic amines have ability to induce small color-pattern changes. Taken together, the present study suggests that CSH is likely to be secreted from trachea-associated endocrine cells upon cold-shock treatment and that tungstate may change color patterns via its direct action on wings.

Selective imaging of nano-particle contrast agents by a single-shot x-ray diffraction technique

Iron oxide nano-particles have very different x-ray diffraction properties from tissue. They can be clearly visualized against suppressed tissue background in a single-shot x-ray diffraction imaging technique. This technique is able to acquire both diffraction and absorption images from a single grating-modulated projection image through analysis in the spatial frequency domain. We describe the use of two orthogonal transmission gratings to selectively retain diffraction signal from iron oxide particles that are larger than a threshold size, while eliminating the background signal from soft tissue and bone. This approach should help the tracking of functionalized particles in cell labeling and targeted therapy.

A switch in the control of growth of the wing imaginal disks of Manduca sexta

BACKGROUND

Insulin and ecdysone are the key extrinsic regulators of growth for the wing imaginal disks of insects. In vitro tissue culture studies have shown that these two growth regulators act synergistically: either factor alone stimulates only limited growth, but together they stimulate disks to grow at a rate identical to that observed in situ. It is generally thought that insulin signaling links growth to nutrition, and that starvation stops growth because it inhibits insulin secretion. At the end of larval life feeding stops but the disks continue to grow, so at that time disk growth has become uncoupled from nutrition. We sought to determine at exactly what point in development this uncoupling occurs.

METHODOLOGY

Growth and cell proliferation in the wing imaginal disks and hemolymph carbohydrate concentrations were measured at various stages in the last larval instar under experimental conditions of starvation, ligation, rescue, and hormone treatment.

PRINCIPAL FINDINGS

Here we show that in the last larval instar of M. sexta, the uncoupling of nutrition and growth occurs as the larva passes the critical weight. Before this time, starvation causes a decline in hemolymph glucose and trehalose and a cessation of wing imaginal disks growth, which can be rescued by injections of trehalose. After the critical weight the trehalose response to starvation disappears, and the expression of insulin becomes decoupled from nutrition. After the critical weight the wing disks loose their sensitivity to repression by juvenile hormone, and factors from the abdomen, but not the brain, are required to drive continued growth.

CONCLUSIONS

During the last larval instar imaginal disk growth becomes decoupled from somatic growth at the time that the endocrine events of metamorphosis are initiated. These regulatory changes ensure that disk growth continues uninterrupted when the nutritive and endocrine signals undergo the drastic changes associated with metamorphosis.

Effects of the essential oil constituent thymol and other neuroactive chemicals on flight motor activity and wing beat frequency in the blowfly Phaenicia sericata

BACKGROUND

The effects were evaluated of the plant terpenoid thymol and eight other neuroactive compounds on flight muscle impulses (FMIs) and wing beat frequency (WBF) of tethered blowflies (Phaenicia sericata Meig.).

RESULTS

The electrical activity of the dorsolongitudinal flight muscles was closely linked to the WBF of control insects. Topically applied thymol inhibited WBF within 15-30 min and reduced FMI frequency. Octopamine and chlordimeform caused a similar, early-onset bursting pattern that decreased in amplitude with time. Desmethylchlordimeform blocked wing beating within 60 min and generated a profile of continuous but lower-frequency FMIs. Fipronil suppressed wing beating and induced a pattern of continuous, variable-frequency spiking that diminished gradually over 6 h. Cypermethrin- and rotenone-treated flies had initial strong FMIs that declined with time. In flies injected with GABA, the FMIs were generally unidirectional and frequency was reduced, as was seen with thymol.

CONCLUSIONS

Thymol readily penetrates the cuticle and interferes with flight muscle and central nervous function in the blowfly. The similarity of the action of thymol and GABA suggests that this terpenoid acts centrally in blowflies by mimicking or facilitating GABA action.

Recombinagenic activity of water and sediment from Sinos River and Araçá and Garças Streams (Canoas, Brazil), in the Drosophila wing spot test

This study characterizes the likely interaction of surface water and sediment samples with DNA to quantitatively and qualitatively establish their mutagenic and/or recombinagenic activity. Samples were collected at 5 different sites within the area of Araçá Stream and 2 different sites within the Sinos River mouth and Garças Stream in the municipality of Canoas, RS, Brazil. The area is impacted by untreated urban discharges (sites 1-7), agricultural pesticides (sites 5 and 7), hospital waste (site 3), animal dejects (site 5), small industries (sites 4, 5 and 6) and vehicular discharges (sites 2, 4, 5 and 6). The wing Somatic Mutation and Recombination Test (SMART) in Drosophila melanogaster was used. The test detects simultaneously mutations and recombination induced by the activity of genotoxins of direct and indirect action. All the samples displayed a massive recombinagenic response, but no mutagenic activity was detected in any of the evaluated samples. This study was done in D. melanogaster with unprocessed water and sediment samples attributing a massive and exclusive recombinagenic action associated to the induction of homologous recombination--a genetic phenomenon involved in the loss of heterozygosity.

Fluctuating wing asymmetry and hepatic concentrations of persistent organic pollutants are associated in European shag (Phalacrocorax aristotelis) chicks

In aquatic birds, high body burdens of persistent organic pollutants (POPs) have been associated with developmental effects related to growth, increased fluctuating wing asymmetry, and disruption of the thyroid hormone, vitamin A (retinol) and vitamin E (tocopherol) homeostasis. The aim of the present study was to examine if morphological variables (body mass, liver mass, wing length, tarsus length and head length), fluctuating asymmetry of the wings and tarsus, growth rates and endocrine variables (thyroid hormones, retinol and tocopherol) were associated with hepatic levels of POPs (PCBs, OCPs and PBDEs) in 21 day old chicks of European shag (Phalacrocorax aristotelis). Partial Least Squares (PLS) analysis showed that fluctuating asymmetry of wing bone length (FA(WBL)) was affected by PCB-105, -118, -138, -153, and -180 (r(2)x=0.88, r(2)y=0.35, q(2)=0.29). Bivariate correlation confirmed significant positive relationships between FA(WBL) and each of these PCB congeners. In the PLS model no other biological variables were significantly affected by any of the POPs. Levels of POPs were much lower in the shag chicks than in eggs and in hatchlings from the same breeding colony, most likely due to growth dilution of the compounds. We suggest that the effects of the PCBs on FA(WBL) may be due to effects of these compounds on bone growth and bone structure. FA(WBL) may have functional effects on the fitness if it persists after fledging.

Translocation of neonicotinoid insecticides from coated seeds to seedling guttation drops: a novel way of intoxication for bees

The death of honey bees, Apis mellifera L., and the consequent colony collapse disorder causes major losses in agriculture and plant pollination worldwide. The phenomenon showed increasing rates in the past years, although its causes are still awaiting a clear answer. Although neonicotinoid systemic insecticides used for seed coating of agricultural crops were suspected as possible reason, studies so far have not shown the existence of unquestionable sources capable of delivering directly intoxicating doses in the fields. Guttation is a natural plant phenomenon causing the excretion of xylem fluid at leaf margins. Here, we show that leaf guttation drops of all the corn plants germinated from neonicotinoid-coated seeds contained amounts of insecticide constantly higher than 10 mg/l, with maxima up to 100 mg/l for thiamethoxam and clothianidin, and up to 200 mg/l for imidacloprid. The concentration of neonicotinoids in guttation drops can be near those of active ingredients commonly applied in field sprays for pest control, or even higher. When bees consume guttation drops, collected from plants grown from neonicotinoid-coated seeds, they encounter death within few minutes.

Antigenotoxic effects of Citrus aurentium L. fruit peel oil on mutagenicity of two alkylating agents and two metals in the Drosophila wing spot test

Antigenotoxic effects of Citrus aurentium L. (Rutaceae) fruit peel oil (CPO) in combination with mutagenic metals and alkylating agents were studied using the wing spot test of D. melanogaster. The four reference mutagens, potassium dichromate (K2Cr2O7), cobalt chloride (CoCl2), ethylmethanesulfonate (EMS), and N-ethyl-N-nitrosourea (ENU) were clearly genotoxic. CPO alone at doses from 0.1 to 0.5% in Tween 80 was not mutagenic and did not enhance the mutagenic effect of the reference mutagens. However, antigenotoxic effects of CPO were clearly demonstrated in chronic cotreatments with mutagens and oil, by a significant decrease in wing spots induced by all four mutagens. The D. melanogaster wing spot test was found to be a suitable assay for detecting antigenotoxic effects in vivo.

Genotoxic evaluation of two halonitromethane disinfection by-products in the Drosophila wing-spot test

Few studies on the genotoxicity of halonitromethanes (HNMs) have been done. This limited information on their potential genotoxic risk gives special relevance to the collection of new data on their potential genotoxic activity. In the present study we have analyzed the genotoxicity of two HNMs namely bromonitromethane (BNM) and trichloronitromethane (TCNM) in the in vivo wing somatic mutation and recombination test in Drosophila, also known as the wing-spot assay. This test is based on the principle that loss of heterozygosis and the corresponding expression of the suitable recessive markers, multiple wing hairs (mwh) and flare-3 (flr(3)), can lead to the formation of mutant clones in larval cells, which are then expressed as spots on the wings of adult flies. BNM and TCNM were supplied to third instar larvae (72+/-4 h-old) at concentrations ranging from 0.1 to 2 mM. The results showed that none of the three categories of mutant spots recorded (small, large, and twin) increased significantly by the treatments, independently of the dose supplied, indicating that the selected HNMs exhibit a lack of genotoxic activity in the wing-spot assay of Drosophila melanogaster. These results contribute to increase the genotoxicity database on the HNMs.

Sublethal effects of four insecticides on the reproduction and wing formation of brown planthopper, Nilaparvata lugens

BACKGROUND

The brown planthopper (BPH), Nilaparvata lugens Stål, is a major rice pest in many parts of Asia. Neonicotinoids such as imidacloprid and dinotefuran are widely used for control of this pest, and resistance to these insecticides has developed in recent years. This pest has also been widely exposed to triazophos and fenvalerate, although these insecticides are not used for the control of the pest directly. Here, the effects of sublethal doses of these four insecticides on the reproduction and wing formation in BPH were examined.

RESULTS

Imidacloprid and dinotefuran reduced the fecundity of BPH to 68.8% and 52.4% in macropterous families, and to 57.9% and 43.1% in brachypterous families, when compared with the untreated controls. By contrast, triazophos and fenvalerate increased fecundity. In both macropterous and brachypterous families, sublethal doses of imidacloprid and dinotefuran showed significant induction of macropterous adults.

CONCLUSION

Imidacloprid and dinotefuran could reduce the fecundity of BPH to a significant extent, demonstrating further activity against this pest in addition to their direct toxicity. The significant induction of macropterous adults by sublethal doses of imidacloprid and dinotefuran is of importance in the management of this pest, particularly in the areas of predicting the size of emigrating populations and the numbers of insects likely to occur in newly colonized areas.