RESUMEN
Ionizing radiation (IR) is used to treat half of all cancer patients because of its ability to kill cells. IR, however, can induce stem cell-like properties in non-stem cancer cells, potentiating tumor regrowth and reduced therapeutic success. We identified previously a subpopulation of cells in Drosophila larval wing discs that exhibit IR-induced stem cell-like properties. These cells reside in the future wing hinge, are resistant to IR-induced apoptosis, and are capable of translocating, changing fate, and participating in regenerating the pouch that suffers more IR-induced apoptosis. We used here a combination of lineage tracing, FACS-sorting of cells that change fate, genome-wide RNAseq, and functional testing of 42 genes, to identify two key changes that are required cell-autonomously for IR-induced hinge-to-pouch fate change: (1) repression of hinge determinants Wg (Drosophila Wnt1) and conserved zinc-finger transcription factor Zfh2 and (2) upregulation of three ribosome biogenesis factors. Additional data indicate a role for Myc, a transcriptional activator of ribosome biogenesis genes, in the process. These results provide a molecular understanding of IR-induced cell fate plasticity that may be leveraged to improve radiation therapy.
Asunto(s)
Proteínas de Drosophila/genética , Drosophila melanogaster/fisiología , Perfilación de la Expresión Génica/métodos , Regeneración/efectos de la radiación , Animales , Apoptosis , Plasticidad de la Célula , Separación Celular , Supervivencia Celular/efectos de la radiación , Proteínas de Unión al ADN/genética , Drosophila melanogaster/genética , Drosophila melanogaster/efectos de la radiación , Citometría de Flujo , Regulación del Desarrollo de la Expresión Génica/efectos de la radiación , Larva/genética , Larva/fisiología , Larva/efectos de la radiación , RNA-Seq , Factores de Transcripción/genética , Secuenciación del Exoma , Alas de Animales/fisiología , Alas de Animales/efectos de la radiación , Proteína Wnt1/genéticaRESUMEN
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 (1-9â¯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 (20â¯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 3â¯h of pretreatment respect to percentage induced in 20â¯Gy control group. Whilst amifostine® was associated with lower genetic damage after pre-treatment of 1 and 3â¯h, this did not attain significance. These findings suggest that the tested porphyrins may have some potential as radioprotectant agents.
Asunto(s)
Amifostina/farmacología , Bilirrubina/farmacología , Clorofilidas/farmacología , Drosophila melanogaster/efectos de los fármacos , Drosophila melanogaster/efectos de la radiación , Protoporfirinas/farmacología , Protectores contra Radiación/farmacología , Animales , Drosophila melanogaster/genética , Femenino , Masculino , Pruebas de Mutagenicidad , Mutación/efectos de los fármacos , Recombinación Genética/efectos de los fármacos , Alas de Animales/efectos de los fármacos , Alas de Animales/efectos de la radiaciónRESUMEN
The wings of Lepidoptera contain a matrix of living cells whose function requires appropriate temperatures. However, given their small thermal capacity, wings can overheat rapidly in the sun. Here we analyze butterfly wings across a wide range of simulated environmental conditions, and find that regions containing living cells are maintained at cooler temperatures. Diverse scale nanostructures and non-uniform cuticle thicknesses create a heterogeneous distribution of radiative cooling that selectively reduces the temperature of structures such as wing veins and androconial organs. These tissues are supplied by circulatory, neural and tracheal systems throughout the adult lifetime, indicating that the insect wing is a dynamic, living structure. Behavioral assays show that butterflies use wings to sense visible and infrared radiation, responding with specialized behaviors to prevent overheating of their wings. Our work highlights the physiological importance of wing temperature and how it is exquisitely regulated by structural and behavioral adaptations.
Asunto(s)
Adaptación Fisiológica/fisiología , Conducta Animal , Mariposas Diurnas/fisiología , Termotolerancia/fisiología , Alas de Animales/fisiología , Animales , Metabolismo Energético/fisiología , Hemolinfa/fisiología , Rayos Infrarrojos , Modelos Biológicos , Nanoestructuras , Energía Solar , Temperatura , Termodinámica , Sensación Térmica , Alas de Animales/anatomía & histología , Alas de Animales/citología , Alas de Animales/efectos de la radiaciónRESUMEN
The role of dose rate (DR) on biological effects of ionizing radiation is an area of significant research focus and relevant to environmental exposures. The present investigation was aimed to examine the direct relationship between viability and genotoxicity in Drosophila melanogaster, induced by gamma rays in a range of doses from 2 to 35 Gy administered at three different DR. Results indicated that larval-adult viability was reduced in relation to dose but not DR. No marked differences were found in the LD50 produced by differing DR tested. Frequencies of somatic mutation and recombination increased in direct correlation with dose and DR. Data demonstrate the importance of determination of the relationship between viability and genotoxicity induced by DR in in vivo systems for toxicological and radioprotection studies.
Asunto(s)
Daño del ADN/efectos de la radiación , Drosophila melanogaster/efectos de la radiación , Rayos gamma/efectos adversos , Alas de Animales/efectos de la radiación , Animales , Relación Dosis-Respuesta en la Radiación , Femenino , Larva/efectos de la radiación , Pruebas de Mutagenicidad , Alas de Animales/crecimiento & desarrolloRESUMEN
Purpose: To reveal the effects of Ultraviolet-C (UV-C) on the elytra and hindwing morphology of Tribolium castaneum. Material and methods: Zero-day-old-pupae were irradiated with UV-C at a distance of 35 cm for 1, 2, 4, 8, 16, 32, or 64 min. Changes in wing morphologies were examined using light and scanning electron microscope. Results: UV-C radiation decreased the adult emergence rate and the insect body mass. Morphological changes of the elytra and hindwings in the adults were classified into nine grades. The treated insects had wrinkled and split elytra, and hindwings were not folded properly. Radiation altered the size of elytra, hindwings and wing shape. An analysis of the color intensity indicated that the irradiated beetles had darker elytra. The veins of hindwings became darker, while the membranous area had a lighter color than the control. UV-C radiation also affected the thickness of the elytra. Scanning electron microscopy revealed that UV-C caused deformity of elytra surface and decreased the number of hair sensilla. Conclusions: Results indicate that the elytra and hindwing morphology were altered by UV-C radiation. However, further analysis is required to evaluate the response of T. castaneum to UV-C radiation at the gene level.
Asunto(s)
Control de Plagas/métodos , Pupa/anatomía & histología , Pupa/efectos de la radiación , Tribolium/anatomía & histología , Tribolium/efectos de la radiación , Rayos Ultravioleta , Alas de Animales/efectos de la radiación , Animales , Tamaño Corporal/efectos de la radiación , Tamaño de los Órganos/efectos de la radiación , Pigmentación/efectos de la radiación , Tribolium/crecimiento & desarrollo , Alas de Animales/anatomía & histología , Alas de Animales/metabolismoRESUMEN
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.
Asunto(s)
Compuestos de Cromo/farmacología , Drosophila melanogaster/genética , Alas de Animales/citología , Animales , Medios de Cultivo Condicionados , Daño del ADN/efectos de los fármacos , Relación Dosis-Respuesta en la Radiación , Drosophila melanogaster/efectos de los fármacos , Drosophila melanogaster/efectos de la radiación , Femenino , Tolerancia a Radiación , Radiación Ionizante , Alas de Animales/efectos de los fármacos , Alas de Animales/efectos de la radiaciónRESUMEN
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.
Asunto(s)
Antioxidantes/farmacología , Ácido Ascórbico/farmacología , Drosophila melanogaster/efectos de los fármacos , Rayos gamma/efectos adversos , Protectores contra Radiación/farmacología , Animales , Daño del ADN , Relación Dosis-Respuesta en la Radiación , Drosophila melanogaster/genética , Drosophila melanogaster/efectos de la radiación , Femenino , Larva/efectos de los fármacos , Larva/genética , Larva/efectos de la radiación , Masculino , Mutación , Alas de Animales/anomalías , Alas de Animales/efectos de los fármacos , Alas de Animales/efectos de la radiaciónRESUMEN
Mre11 is a key player for DNA double strand break repair. Previous studies have shown that mammalian Mre11 is methylated at multiple arginines in its C-terminal Glycine-Arginine-Rich motif (GAR) by protein arginine methyltransferase PRMT1. Here, we found that the Drosophila Mre11 is methylated at arginines 559, 563, 565, and 569 in the GAR motif by DART1, the Drosophila homolog of PRMT1. Mre11 interacts with DART1 in S2 cells, and this interaction does not require the GAR motif. Arginines methylated Mre11 localizes exclusively in the nucleus as soluble nuclear protein or chromatin-binding protein. To study the in vivo functions of methylation, we generated the single Arg-Ala and all Arginines mutated flies. We found these mutants were sensitive to ionizing radiation. Furthermore, Arg-Ala mutated flies had no irradiation induced G2/M checkpoint defect in wing disc and eye disc. Thus, we provided evidence that arginines in Drosophila Mre11 are methylated by DART1 methytransferase and flies loss of arginine methylation are sensitive to irradiation.
Asunto(s)
Arginina/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Drosophila melanogaster/efectos de la radiación , Endodesoxirribonucleasas/metabolismo , Radiación Ionizante , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Animales , Puntos de Control del Ciclo Celular/genética , Puntos de Control del Ciclo Celular/efectos de la radiación , Línea Celular , Daño del ADN , Proteínas de Drosophila/química , Endodesoxirribonucleasas/química , Ojo/citología , Ojo/metabolismo , Ojo/efectos de la radiación , Fase G2/genética , Fase G2/efectos de la radiación , Técnicas de Silenciamiento del Gen , Metilación , Metiltransferasas/metabolismo , Mitosis/genética , Mitosis/efectos de la radiación , Mutación/genética , Análisis de Supervivencia , Alas de Animales/metabolismo , Alas de Animales/efectos de la radiaciónRESUMEN
Strategies to deal with global radiation may be related to important aspects of species biology and ecology by reflecting, transmitting or absorbing the radiation of varying wavelengths differently. The elytra capacity to manage infrared, visible and ultraviolet radiations (from 185 to 1400 nm) was assessed with a spectrophotometric analysis in five Canthon species of dung beetles; we calculated the reflectance, transmittance and absorbance capacity of the elytra of these species. These species have different ecologies: two species preferentially inhabit forest areas (Canthon angularis and Canthon lividus lividus), two species preferentially inhabit open areas (Canthon chalybaeus and Canthon tetraodon) including agricultural crops, and one species does not present a clear habitat preference and can be found in both habitats (Canthon quinquemaculatus). All the species show a similar pattern in which the light from shorter wavelengths and higher frequencies is almost entirely absorbed by the elytra, while radiation from longer wavelengths and lower frequencies can mostly pass through the elytra. However, C. quinquemaculatus seems to have significantly higher rates of reflectance and transmittance in the visible- and near-infrared spectrum. This different pattern found in C. quinquemaculatus may be associated with its capacity to establish populations both in agricultural and forest areas.
Asunto(s)
Escarabajos/efectos de la radiación , Rayos Infrarrojos , Rayos Ultravioleta , Alas de Animales/efectos de la radiación , Animales , Escarabajos/clasificación , Escarabajos/fisiología , Productos Agrícolas/parasitología , Ecosistema , Especificidad de la Especie , Espectrofotometría Infrarroja , Espectrofotometría UltravioletaRESUMEN
We report here a study of regeneration in Drosophila larval wing imaginal discs after damage by ionizing radiation. We detected faithful regeneration that restored a wing disc and abnormal regeneration that produced an extra wing disc. We describe a sequence of changes in cell number, location and fate that occur to produce an ectopic disc. We identified a group of cells that not only participate in ectopic disc formation but also recruit others to do so. STAT92E (Drosophila STAT3/5) and Nurf-38, which encodes a member of the Nucleosome Remodeling Factor complex, oppose each other in these cells to modulate the frequency of ectopic disc growth. The picture that emerges is one in which activities like STAT increase after radiation damage and fulfill essential roles in rebuilding the tissue. But such activities must be kept in check so that one and only one wing disc is regenerated.
Asunto(s)
Proteínas de Drosophila/genética , Pirofosfatasas/genética , Regeneración/genética , Factores de Transcripción STAT/genética , Proteína Wnt1/genética , Animales , Apoptosis/efectos de la radiación , Drosophila melanogaster/genética , Drosophila melanogaster/crecimiento & desarrollo , Drosophila melanogaster/efectos de la radiación , Regulación del Desarrollo de la Expresión Génica/efectos de la radiación , Discos Imaginales/crecimiento & desarrollo , Discos Imaginales/lesiones , Discos Imaginales/efectos de la radiación , Larva/genética , Larva/crecimiento & desarrollo , Larva/efectos de la radiación , Regeneración/efectos de la radiación , Alas de Animales/crecimiento & desarrollo , Alas de Animales/efectos de la radiaciónRESUMEN
While white-nose syndrome (WNS) has decimated hibernating bat populations in the Nearctic, species from the Palearctic appear to cope better with the fungal skin infection causing WNS. This has encouraged multiple hypotheses on the mechanisms leading to differential survival of species exposed to the same pathogen. To facilitate intercontinental comparisons, we proposed a novel pathogenesis-based grading scheme consistent with WNS diagnosis histopathology criteria. UV light-guided collection was used to obtain single biopsies from Nearctic and Palearctic bat wing membranes non-lethally. The proposed scheme scores eleven grades associated with WNS on histopathology. Given weights reflective of grade severity, the sum of findings from an individual results in weighted cumulative WNS pathology score. The probability of finding fungal skin colonisation and single, multiple or confluent cupping erosions increased with increase in Pseudogymnoascus destructans load. Increasing fungal load mimicked progression of skin infection from epidermal surface colonisation to deep dermal invasion. Similarly, the number of UV-fluorescent lesions increased with increasing weighted cumulative WNS pathology score, demonstrating congruence between WNS-associated tissue damage and extent of UV fluorescence. In a case report, we demonstrated that UV-fluorescence disappears within two weeks of euthermy. Change in fluorescence was coupled with a reduction in weighted cumulative WNS pathology score, whereby both methods lost diagnostic utility. While weighted cumulative WNS pathology scores were greater in the Nearctic than Palearctic, values for Nearctic bats were within the range of those for Palearctic species. Accumulation of wing damage probably influences mortality in affected bats, as demonstrated by a fatal case of Myotis daubentonii with natural WNS infection and healing in Myotis myotis. The proposed semi-quantitative pathology score provided good agreement between experienced raters, showing it to be a powerful and widely applicable tool for defining WNS severity.
Asunto(s)
Ascomicetos/fisiología , Quirópteros/microbiología , Enfermedades de la Piel/patología , Alas de Animales/microbiología , Alas de Animales/patología , Animales , Ascomicetos/genética , Quirópteros/metabolismo , ADN de Hongos/genética , Modelos Lineales , Imagen Óptica , Filogenia , Índice de Severidad de la Enfermedad , Enfermedades de la Piel/microbiología , Rayos Ultravioleta , Alas de Animales/efectos de la radiaciónRESUMEN
While numerous papers have investigated the effects of thermal stress on the pigmentary colours of butterfly wings, such studies regarding structural colours are mostly lacking, despite the important role they play in sexual communication. To gain insight into the possible differences between the responses of the two kinds of colouration, we investigated the effects of prolonged cold stress (cooling at 5 °C for up to 62 days) on the pupae of Polyommatus icarus butterflies. The wing surfaces coloured by photonic crystal-type nanoarchitectures (dorsal) and by pigments (ventral) showed markedly different behaviours. The ventral wing surfaces exhibited stress responses proportional in magnitude to the duration of cooling and showed the same trend for all individuals, irrespective of their sex. On the dorsal wing surface of the males, with blue structural colouration, a smaller magnitude response was found with much more pronounced individual variations, possibly revealing hidden genetic variations. Despite the typical, pigmented brown colour of the dorsal wing surface of the females, all cooled females exhibited a certain degree of blue colouration. UV-VIS spectroscopy, optical microscopy, and scanning and transmission electron microscopy were used to evaluate the magnitude and character of the changes induced by the prolonged cold stress.
Asunto(s)
Mariposas Diurnas/fisiología , Mariposas Diurnas/efectos de la radiación , Frío , Pigmentos Biológicos/metabolismo , Estrés Fisiológico , Alas de Animales/fisiología , Alas de Animales/efectos de la radiación , Animales , Femenino , Masculino , Microscopía , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Pupa/fisiología , Pupa/efectos de la radiación , EspectrofotometríaRESUMEN
Here we report how interference and scattering-enhanced absorption act together to produce the golden wing patches of the burnished brass moth. The key mechanism is scattering on rough internal surfaces of the wing scales, accompanied by a large increase of absorption in the UV-blue spectral range. Unscattered light interferes and efficiently reflects from the multilayer composed of the scales and the wing membranes. The resulting spectrum is remarkably similar to the spectrum of metallic gold. Subwavelength morphology and spectral and absorptive properties of the wings are described. Theories of subwavelength surface scattering and local intensity enhancement are used to quantitatively explain the observed reflectance spectrum.
Asunto(s)
Color , Mariposas Nocturnas , Alas de Animales , Animales , Microscopía , Microscopía Electrónica de Rastreo , Modelos Biológicos , Mariposas Nocturnas/anatomía & histología , Mariposas Nocturnas/efectos de la radiación , Dispersión de Radiación , Alas de Animales/anatomía & histología , Alas de Animales/efectos de la radiaciónRESUMEN
We studied a set of Drosophila melanogaster strains that could be potentially suitable for testing a variety of mutagenic factors. Their genomes contained insertions of the enhancer trap P{lacW} in which the activity of the LacZ reporter is under the control of the reparation genes' regulatory region. We demonstrated that the beta-galactosidase reporter, which is encoded by insertion of P{lacW} element in the gene mus209, is induced by irradiation in the cells of the salivary glands and wing imaginal discs. Despite the fact that the reporting coloration is not associated with the dose of radiation treatment, we found that the induction threshold of the reporter is different for these tissues. Thus, coloration in salivary glands is detectable after the dose of 200 rad and above, whereas the imaginal discs get colored with 500 rad and above. Thereby, multiple thresholds for induction of the reporter in the various tissues allow approximating the received dose.
Asunto(s)
Reparación del ADN/efectos de la radiación , Drosophila melanogaster/efectos de la radiación , Endonucleasas/genética , Rayos gamma/efectos adversos , Operón Lac/efectos de la radiación , beta-Galactosidasa/genética , Animales , Color , Elementos Transponibles de ADN , Relación Dosis-Respuesta en la Radiación , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Endonucleasas/metabolismo , Elementos de Facilitación Genéticos , Regulación de la Expresión Génica , Genes Reporteros , Discos Imaginales/metabolismo , Discos Imaginales/efectos de la radiación , Especificidad de Órganos , Dosis de Radiación , Glándulas Salivales/metabolismo , Glándulas Salivales/efectos de la radiación , Alas de Animales/metabolismo , Alas de Animales/efectos de la radiación , beta-Galactosidasa/metabolismoRESUMEN
Electroactive materials that change shape in response to electrical stimulation can serve as actuators. Electroactive actuators of this type have great utility in a variety of technologies, including biomimetic artificial muscles, robotics, and sensors. Electroactive actuators developed to date often suffer from problems associated with the need to use electrolytes, slow response times, high driving voltages, and short cycle lifetimes. Herein, we report an electrolyte-free, single component, polymer electroactive actuator, which has a fast response time, high durability, and requires a low driving voltage (<5 V). The process employed for production of this material involves wet-spinning of a preorganized camphorsulfonic acid (CSA)-doped polyaniline (PANI) gel, which generates long, flexible, and conductive (â¼270 S/cm) microfibers. Reversible bending motions take place upon application of an alternating current (AC) to the PANI polymer. This motion, promoted by a significantly low driving voltage (<0.5 V) in the presence of an external magnetic field, has a very large swinging speed (9000 swings/min) that lies in the range of those of flies and bees (1000-15000 swings/min) and is fatigue-resistant (>1000000 cycles).
Asunto(s)
Biomimética , Campos Magnéticos , Nanotubos de Carbono/química , Alas de Animales/fisiología , Animales , Estimulación Eléctrica , Electrólitos/química , Movimiento (Física) , Polímeros/química , Robótica , Alas de Animales/efectos de la radiaciónRESUMEN
Curcumin, belonging to a class of natural phenol compounds, has been extensively studied due to its antioxidative, anticancer, anti-inflammatory, and antineurodegenerative effects. Recently, it has been shown to exert dual activities after irradiation, radioprotection, and radiosensitization. Here, we investigated the protective effect of curcumin against radiation damage using D. melanogaster. Pretreatment with curcumin (100 µM) recovered the shortened lifespan caused by irradiation and increased eclosion rate. Flies subjected to high-dose irradiation showed a mutant phenotype of outstretched wings, whereas curcumin pretreatment reduced incidence of the mutant phenotype. Protein carbonylation and formation of γH2Ax foci both increased following high-dose irradiation most likely due to generation of reactive oxygen species. Curcumin pretreatment reduced the amount of protein carbonylation as well as formation of γH2Ax foci. Therefore, we suggest that curcumin acts as an oxidative stress reducer as well as an effective protective agent against radiation damage.
Asunto(s)
Envejecimiento/efectos de los fármacos , Curcumina/farmacología , Drosophila melanogaster/efectos de los fármacos , Drosophila melanogaster/fisiología , Rayos gamma , Estrés Oxidativo/efectos de los fármacos , Animales , Daño del ADN , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/efectos de la radiación , Femenino , Longevidad/efectos de los fármacos , Longevidad/efectos de la radiación , Estrés Oxidativo/efectos de la radiación , Fenotipo , Carbonilación Proteica/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Alas de Animales/efectos de los fármacos , Alas de Animales/efectos de la radiaciónRESUMEN
BACKGROUND: Circadian clocks have been postulated to regulate development time in several species of insects including fruit flies Drosophila melanogaster. Previously we have reported that selection for faster pre-adult development reduces development time (by ~19 h or ~11%) and clock period (by ~0.5 h), suggesting a role of circadian clocks in the regulation of development time in D. melanogaster. We reasoned that these faster developing flies could serve as a model to study stage-specific interaction of circadian clocks and developmental events with the environmental light/dark (LD) conditions. We assayed the duration of three pre-adult stages in the faster developing (FD) and control (BD) populations under a variety of light regimes that are known to modulate circadian clocks and pre-adult development time of Drosophila to examine the role of circadian clocks in the timing of pre-adult developmental stages. RESULTS: We find that the duration of pre-adult stages was shorter under constant light (LL) and short period light (L)/dark (D) cycles (L:D = 10:10 h; T20) compared to the standard 24 h day (L:D = 12:12 h; T24), long LD cycles (L:D = 14:14 h; T28) and constant darkness (DD). The difference in the duration of pre-adult stages between the FD and BD populations was significantly smaller under the three LD cycles and LL compared to DD, possibly due to the fact that clocks of both FD and BD flies are driven at the same pace in the three LD regimes owing to circadian entrainment, or are rendered dysfunctional under LL. CONCLUSIONS: These results suggest that interaction between light regimes and circadian clocks regulate the duration of pre-adult developmental stages in fruit flies D. melanogaster.
Asunto(s)
Relojes Circadianos/fisiología , Drosophila melanogaster/efectos de la radiación , Luz , Fotoperiodo , Análisis de Varianza , Animales , Oscuridad , Drosophila melanogaster/crecimiento & desarrollo , Larva/crecimiento & desarrollo , Larva/efectos de la radiación , Óvulo/crecimiento & desarrollo , Óvulo/efectos de la radiación , Pigmentación/fisiología , Pigmentación/efectos de la radiación , Factores de Tiempo , Alas de Animales/crecimiento & desarrollo , Alas de Animales/fisiología , Alas de Animales/efectos de la radiaciónRESUMEN
We report a phenomenon wherein induction of cell death by a variety of means in wing imaginal discs of Drosophila larvae resulted in the activation of an anti-apoptotic microRNA, bantam. Cells in the vicinity of dying cells also become harder to kill by ionizing radiation (IR)-induced apoptosis. Both ban activation and increased protection from IR required receptor tyrosine kinase Tie, which we identified in a genetic screen for modifiers of ban. tie mutants were hypersensitive to radiation, and radiation sensitivity of tie mutants was rescued by increased ban gene dosage. We propose that dying cells activate ban in surviving cells through Tie to make the latter cells harder to kill, thereby preserving tissues and ensuring organism survival. The protective effect we report differs from classical radiation bystander effect in which neighbors of irradiated cells become more prone to death. The protective effect also differs from the previously described effect of dying cells that results in proliferation of nearby cells in Drosophila larval discs. If conserved in mammals, a phenomenon in which dying cells make the rest harder to kill by IR could have implications for treatments that involve the sequential use of cytotoxic agents and radiation therapy.
Asunto(s)
Muerte Celular/genética , Discos Imaginales , MicroARNs/genética , Tolerancia a Radiación/genética , Animales , Muerte Celular/efectos de la radiación , Supervivencia Celular/genética , Supervivencia Celular/efectos de la radiación , Drosophila melanogaster/genética , Drosophila melanogaster/efectos de la radiación , Larva/efectos de la radiación , MicroARNs/efectos de la radiación , Radiación Ionizante , Alas de Animales/metabolismo , Alas de Animales/efectos de la radiaciónRESUMEN
Biological effects of exposure to red light (lambda = 660 +/- 10 nm) on the viability and morphophysiological characteristics of Drosophila melanogaster have been studied. The ability of this physical agent to modify these features is shown. The degree of expression and impact of biological effects depend on the dose, functional and genetic status of the organism. The study of the life expectancy of the exposed to EHF and white light D. melanogaster has revealed that expression of the features depends on the radiation doses, genotype, sex, the nature of the position of wings and lighting conditions. It has been found that the dark mode (24 h-night) is more favorable than the artificial lighting. Individuals with the left wing at the top are more sensitive to the external factors.