RESUMO
Gamma radiation produces DNA instability and impaired phenotype. Previously, we observed negative effects on phenotype, DNA methylation, and gene expression profiles, in offspring of zebrafish exposed to gamma radiation during gametogenesis. We hypothesize that previously observed effects are accompanied with changes in the expression profile of non-coding RNAs, inherited by next generations. Non-coding RNA expression profile was analysed in F1 offspring (5.5 h post-fertilization) by high-throughput sequencing 1 year after parental irradiation (8.7 mGy/h, 5.2 Gy total dose). Using our previous F1-γ genome-wide gene expression data (GSE98539), hundreds of mRNAs were predicted as targets of differentially expressed (DE) miRNAs, involved in pathways such as insulin receptor, NFkB and PTEN signalling, linking to apoptosis and cancer. snRNAs belonging to the five major spliceosomal snRNAs were down-regulated in the F1-γ group, Indicating transcriptional and post-transcriptional alterations. In addition, DEpiRNA clusters were associated to 9 transposable elements (TEs) (LTR, LINE, and TIR) (p = 0.0024), probable as a response to the activation of these TEs. Moreover, the expression of the lincRNAs malat-1, and several others was altered in the offspring F1, in concordance with previously observed phenotypical alterations. In conclusion, our results demonstrate diverse gamma radiation-induced alterations in the ncRNA profiles of F1 offspring observable 1 year after parental irradiation.
Assuntos
Raios gama/efeitos adversos , RNA não Traduzido/genética , Peixe-Zebra/genética , Animais , Dano ao DNA/genética , Dano ao DNA/efeitos da radiação , Metilação de DNA/genética , Metilação de DNA/efeitos da radiação , Gametogênese/genética , Gametogênese/efeitos da radiação , Transdução de Sinais/genética , Transdução de Sinais/efeitos da radiação , Transcriptoma/genética , Transcriptoma/efeitos da radiaçãoRESUMO
Artificial light at night (ALAN) can have negative impacts on the health of humans and ecosystems.1-4 Marine organisms, including coral reefs in particular, rely on the natural light cycles of sunlight and moonlight to regulate various physiological, biological, and behavioral processes.5-8 Here, we demonstrate that light pollution caused delayed gametogenesis and unsynchronized gamete release in two coral species, Acropora millepora and Acropora digitifera, from the Indo-Pacific Ocean. Given the urbanization along major coasts, light pollution could thus further threaten coral communities' populations, which are already under severe degradation. A worldwide-modeled light pollution impact assessment is provided, which can help incorporate an important variable in coral reef conservation planning.
Assuntos
Antozoários/fisiologia , Gametogênese/efeitos da radiação , Iluminação/efeitos adversos , Fotoperíodo , Urbanização , Animais , Antozoários/efeitos da radiação , Conservação dos Recursos Naturais , Recifes de Corais , Oceano PacíficoRESUMO
Ionizing radiation is a recognized genotoxic agent, however, little is known about the role of the functional form of DNA in these processes. Post translational modifications on histone proteins control the organization of chromatin and hence control transcriptional responses that ultimately affect the phenotype. The purpose of this study was to investigate effects on chromatin caused by ionizing radiation in fish. Direct exposure of zebrafish (Danio rerio) embryos to gamma radiation (10.9 mGy/h for 3h) induced hyper-enrichment of H3K4me3 at the genes hnf4a, gmnn and vegfab. A similar relative hyper-enrichment was seen at the hnf4a loci of irradiated Atlantic salmon (Salmo salar) embryos (30 mGy/h for 10 days). At the selected genes in ovaries of adult zebrafish irradiated during gametogenesis (8.7 and 53 mGy/h for 27 days), a reduced enrichment of H3K4me3 was observed, which was correlated with reduced levels of histone H3 was observed. F1 embryos of the exposed parents showed hyper-methylation of H3K4me3, H3K9me3 and H3K27me3 on the same three loci, while these differences were almost negligible in F2 embryos. Our results from three selected loci suggest that ionizing radiation can affect chromatin structure and organization, and that these changes can be detected in F1 offspring, but not in subsequent generations.
Assuntos
Raios gama/efeitos adversos , Loci Gênicos/efeitos da radiação , Código das Histonas/efeitos da radiação , Salmo salar/genética , Peixe-Zebra/genética , Animais , Desenvolvimento Embrionário/genética , Desenvolvimento Embrionário/efeitos da radiação , Gametogênese/efeitos da radiação , Loci Gênicos/genética , Histonas/química , Histonas/metabolismo , Lisina/metabolismo , Metilação/efeitos da radiação , Salmo salar/embriologia , Salmo salar/fisiologia , Peixe-Zebra/embriologia , Peixe-Zebra/fisiologiaRESUMO
The biological effects of gamma radiation may exert damage beyond that of the individual through its deleterious effects on reproductive function. Impaired reproductive performance can result in reduced population size over consecutive generations. In a continued effort to investigate reproductive and heritable effects of ionizing radiation, we recently demonstrated adverse effects and genomic instability in progeny of parents exposed to gamma radiation. In the present study, genotoxicity and effects on the reproduction following subchronic exposure during a gametogenesis cycle to 60Co gamma radiation (27 days, 8.7 and 53â¯mGy/h, total doses 5.2 and 31â¯Gy) were investigated in the adult wild-type zebrafish (Danio rerio). A significant reduction in embryo production was observed one month after exposure in the 53â¯mGy/h exposure group compared to control and 8.7â¯mGy/h. One year later, embryo production was significantly lower in the 53â¯mGy/h group compared only to control, with observed sterility, accompanied by a regression of reproductive organs in 100% of the fish 1.5 years after exposure. Histopathological examinations revealed no significant changes in the testis in the 8.7â¯mGy/h group, while in 62.5% of females exposed to this dose rate the oogenesis was found to be only at the early previtellogenic stage. The DNA damage determined in whole blood, 1.5 years after irradiation, using a high throughput Comet assay, was significantly higher in the exposed groups (1.2 and 3-fold increase in 8.7 and 53â¯mGy/h females respectively; 3-fold and 2-fold increase in 8.7 and 53â¯mGy/h males respectively) compared to controls. A significantly higher number of micronuclei (4-5%) was found in erythrocytes of both the 8.7 and 53â¯mGy/h fish compared to controls. This study shows that gamma radiation at a dose rate of ≥â¯8.7â¯mGy/h during gametogenesis causes adverse reproductive effects and persistent genotoxicity (DNA damage and increased micronuclei) in adult zebrafish.
Assuntos
Dano ao DNA , Gametogênese/efeitos da radiação , Raios gama/efeitos adversos , Reprodução/efeitos dos fármacos , Peixe-Zebra/genética , Animais , Ensaio Cometa , Relação Dose-Resposta à Radiação , Feminino , Gametogênese/genética , Instabilidade Genômica/efeitos da radiação , Masculino , Óvulo/efeitos da radiação , Reprodução/genética , Testículo/efeitos da radiação , Peixe-Zebra/crescimento & desenvolvimentoRESUMO
Gamma radiation represents a potential health risk to aquatic and terrestrial biota, due to its ability to ionize atoms and molecules in living tissues. The effects of exposure to 60Co gamma radiation in zebrafish (Danio rerio) were studied during two sensitive life stages: gametogenesis (F0: 53 and 8.7mGy/h for 27 days, total doses 31 and 5.2Gy) and embryogenesis (9.6mGy/h for 65h; total dose 0.62Gy). Progeny of F0 exposed to 53mGy/h showed 100% mortality occurring at the gastrulation stage corresponding to 8h post fertilization (hpf). Control and F0 fish exposed to 8.7mGy/h were used to create four lines in the first filial generation (F1): control, G line (irradiated during parental gametogenesis), E line (irradiated during embryogenesis) and GE line (irradiated during parental gametogenesis and embryogenesis). A statistically significant cumulative mortality of GE larva (9.3%) compared to controls was found at 96 hpf. E line embryos hatched significantly earlier compared to controls, G and GE (48-72 hpf). The deformity frequency was higher in G and GE, but not E line compared to controls at 72 hpf. One month after parental irradiation, the formation of reactive oxygen species (ROS) was increased in the G line, but did not significantly differ from controls one year after parental irradiation, while at the same time point it was significantly increased in the directly exposed E and GE lines from 60 to 120 hpf. Lipid peroxidation (LPO) was significantly increased in the G line one year after parental irradiation, while significant increase in DNA damage was detected in both the G and GE compared to controls and E line at 72 hpf. Radiation-induced bystander effects, triggered by culture media from tissue explants and observed as influx of Ca2+ ions through the cellular membrane of the reporter cells, were significantly increased in 72 hpf G line progeny one month after irradiation of the parents. One year after parental irradiation, the bystander effects were increased in the E line compared to controls, but not in progeny of irradiated parents (G and GE lines). Overall, this study showed that irradiation of parents can result in multigenerational oxidative stress and genomic instability in irradiated (GE) and non-irradiated (G) progeny of irradiated parents, including increases in ROS formation, LPO, DNA damage and bystander effects. The results therefore highlight the necessity for multi- and transgenerational studies to assess the environmental impact of gamma radiation.
Assuntos
Gametogênese/efeitos da radiação , Raios gama/efeitos adversos , Instabilidade Genômica/efeitos da radiação , Reprodução/efeitos da radiação , Peixe-Zebra/fisiologia , Animais , Embrião não Mamífero/efeitos da radiação , Peixe-Zebra/genéticaRESUMO
Understanding how toxic contaminants affect wildlife species at various levels of biological organization (subcellular, histological, physiological, organism, and population levels) is a major research goal in both ecotoxicology and radioecology. A mechanistic understanding of the links between different observed perturbations is necessary to predict the consequences for survival, growth, and reproduction, which are critical for population dynamics. In this context, experimental and modeling studies were conducted using the nematode Caenorhabditis elegans. A chronic exposure to external gamma radiation was conducted under controlled conditions. Results showed that somatic growth and reproduction were reduced with increasing dose rate. Modeling was used to investigate whether radiation effects might be assessed using a mechanistic model based upon the dynamic energy budget (DEB) theory. A DEB theory in toxicology (DEB-tox), specially adapted to the case of gamma radiation, was developed. Modelling results demonstrated the suitability of DEB-tox for the analysis of radiotoxicity and suggested that external gamma radiation predominantly induced a direct reduction in reproductive capacity in C. elegans and produced an increase in costs for growth and maturation, resulting in a delay in growth and spawning observed at the highest tested dose rate.
Assuntos
Caenorhabditis elegans/efeitos da radiação , Raios gama/efeitos adversos , Testes de Toxicidade Crônica , Animais , Relação Dose-Resposta à Radiação , Gametogênese/efeitos da radiação , Masculino , Modelos Biológicos , Reprodução/efeitos da radiaçãoRESUMO
The study of radiation effect in Caenorhabditis (C.) elegans has been carried out over three decades and now allow for understanding at the molecular, cellular and individual levels. This review describes the current knowledge of the biological effects of ionizing irradiation with a scope of the germ line, aging and behavior. In germ cells, ionizing radiation induces apoptosis, cell cycle arrest and DNA repair. Lots of molecules involved in these responses and functions have been identified in C. elegans, which are highly conserved throughout eukaryotes. Radiosensitivity and the effect of heavy-ion microbeam irradiation on germ cells with relationship between initiation of meiotic recombination and DNA lesions are discussed. In addition to DNA damage, ionizing radiation produces free radicals, and the free radical theory is the most popular aging theory. A first signal transduction pathway of aging has been discovered in C. elegans, and radiation-induced metabolic oxidative stress is recently noted for an inducible factor of hormetic response and genetic instability. The hormetic response in C. elegans exposed to oxidative stress is discussed with genetic pathways of aging. Moreover, C. elegans is well known as a model organism for behavior. The recent work reported the radiation effects via specific neurons on learning behavior, and radiation and hydrogen peroxide affect the locomotory rate similarly. These findings are discussed in relation to the evidence obtained with other organisms. Altogether, C. elegans may be a good "in vivo" model system in the field of radiation biology.
Assuntos
Envelhecimento/efeitos da radiação , Comportamento Animal/efeitos da radiação , Caenorhabditis elegans/efeitos da radiação , Células Germinativas/efeitos da radiação , Animais , Apoptose/efeitos da radiação , Caenorhabditis elegans/embriologia , Caenorhabditis elegans/crescimento & desenvolvimento , Caenorhabditis elegans/fisiologia , DNA de Helmintos/efeitos da radiação , Transtornos do Desenvolvimento Sexual , Gametogênese/efeitos da radiação , Aprendizagem/efeitos da radiação , Locomoção/efeitos da radiação , Meiose/efeitos da radiação , Modelos Animais , Estresse Oxidativo , Tolerância a Radiação , Transdução de Sinais/efeitos da radiaçãoRESUMO
Cancer in women or men during reproductive life raises fears and dilemmas regarding the ability to have a healthy child. Chemotherapy and radiotherapy increase genetic defects in germ cells, depending on the agent used and the stage of gamete maturation. No increase in miscarriage or congenital malformation rates is detected among children born years post-cancer treatment. However, when pregnancy occurred shortly after treatment, increased abortion and malformation risk was reported. Until more data are available, monitoring of chromosomal aberrations and birth defects is recommended. Complexity of cancer treatment is significantly amplified in women exposed to chemotherapy during pregnancy due to concerns regarding direct maternal risks caused by treatment and risk to the developing embryo-fetus. The potential teratogenic effect of cancer treatment depends upon the developmental stage of the fetus at exposure and on drugs used. During the first trimester, abortion and malformation rates are increased, while second- and third-trimester chemotherapy may increase the risk of stillbirth, fetal growth restriction, and premature birth. Maternal myelosuppression increases bleeding and infection tendency, which can harm the fetus. A multidisciplinary team alerted to possible consequences of cancer treatment on pregnancy outcome should provide the optimal treatment options for these patients.
Assuntos
Antineoplásicos/efeitos adversos , Antineoplásicos/uso terapêutico , Complicações na Gravidez/induzido quimicamente , Resultado da Gravidez , Lesões por Radiação , Aborto Espontâneo , Animais , Ensaios Clínicos como Assunto , Anormalidades Congênitas/etiologia , Modelos Animais de Doenças , Feminino , Gametogênese/efeitos dos fármacos , Gametogênese/efeitos da radiação , Humanos , Recém-Nascido , Masculino , Gravidez , Fatores de RiscoRESUMO
The paper summarises some methodological approaches which may be used in experimental modelling and study of hereditary radiation effects in mammals. These approaches are aimed to the elucidation of the possible specific character (aggravation) of radiation damage in the offspring determined by the participation of two exposed parents in conception. The main attention is drawn to the dependence of hereditary radiation effects yield on the stages of the cell cycle of the parent germ cells at the moment of exposure and to criteria of evaluation of radiation damage in the offspring during the ontogenetic development.
Assuntos
Modelos Animais de Doenças , Efeitos Tardios da Exposição Pré-Natal , Lesões Experimentais por Radiação/genética , Animais , Pai , Feminino , Gametogênese/efeitos da radiação , Masculino , Gravidez , Radiogenética/métodosRESUMO
In experiments with Wistar rats it was shown that the efficiency of mexamine as radioprotector was substantially lower when sex cells of both parents (spermatozoids, spermatids, ovocytes) were irradiated with a dose of 2-4 Gy than after irradiation one parent only. It may be associated with the aggravation of effects in the posterity being conceived from gametes of both exposed parents.
Assuntos
5-Metoxitriptamina/farmacologia , Efeitos Tardios da Exposição Pré-Natal , Animais , Relação Dose-Resposta à Radiação , Pai , Feminino , Gametogênese/efeitos dos fármacos , Gametogênese/efeitos da radiação , Raios gama , Tamanho da Ninhada de Vivíparos/efeitos dos fármacos , Tamanho da Ninhada de Vivíparos/efeitos da radiação , Masculino , Gravidez , Ratos , Ratos Wistar , Irradiação Corporal TotalRESUMO
Acute gamma-irradiation with a dose of 4 Gy of germinal cells of both parents in postmeiotic stages of gametogenesis results in increase of ineffective copulation rate. Antenatal and postnatal ontogenesis of first generation progeny shows worse consequences as compared with only one parent germinal cell irradiation.
Assuntos
Gametogênese/efeitos da radiação , Células Germinativas/efeitos da radiação , Lesões Experimentais por Radiação , Anormalidades Induzidas por Radiação , Animais , Animais Recém-Nascidos , Feminino , Infertilidade/etiologia , Masculino , Óvulo/efeitos da radiação , Gravidez , Doses de Radiação , Ratos , Ratos Wistar , Espermatozoides/efeitos da radiaçãoRESUMO
The data on antenatal and postnatal periods of ontogenesis of the posterity of the first generation of Wistar rats exposed by doses of 2-4 Gy at various terms before conception showed that the realization of radiation effects depended on the stage of gametogenesis of sex cells of both parents at radiation exposure. Stimulating radiation effect (hyperovulation) is accompanied by the higher rate of antenatal and early postnatal death of the posterity. In the rest cases it died mainly at embryogenesis. The most unfavourable factor for ontogenesis of the posterity appeared to be a participation in the fertilization of sex cells exposed at postmeiotic stages of gametogenesis, with the degree of manifestation of radiation effects depending on radiation dose.