A Systematic Analysis of Metal and Metalloid Concentrations in Eight Zebrafish Recirculating Water Systems.

Metals and metalloids are integral to biological processes and play key roles in physiology and metabolism. Nonetheless, overexposure to some metals or lack of others can lead to serious health consequences. In this study, eight zebrafish facilities collaborated to generate a multielement analysis of their centralized recirculating water systems.

Altered non-coding RNA expression profile in F progeny 1 year after parental irradiation is linked to adverse effects in zebrafish.

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.

Inhibition of methyltransferase activity of enhancer of zeste 2 leads to enhanced lipid accumulation and altered chromatin status in zebrafish.

Background: Recent studies indicate that exposure to environmental chemicals may increase susceptibility to developing metabolic diseases. This susceptibility may in part be caused by changes to the epigenetic landscape which consequently affect gene expression and lead to changes in lipid metabolism. The epigenetic modifier enhancer of zeste 2 (Ezh2) is a histone H3K27 methyltransferase implicated to play a role in lipid metabolism and adipogenesis.

Epigenetic, transcriptional and phenotypic responses in two generations of exposed to the DNA methylation inhibitor 5-azacytidine.

The water flea is a keystone species in freshwater ecosystems and has been widely used as a model organism in environmental ecotoxicology. This aquatic crustacean is sensitive to environmental stressors and displays considerable plasticity in adapting to changing environmental conditions. Part of this plasticity may be due to epigenetic regulation of gene expression, including changes to DNA methylation and histone modifications.

Zebrafish: Housing and husbandry recommendations.

This article provides recommendations for the care of laboratory zebrafish () as part of the further implementation of Annex A to the European Convention on the protection of vertebrate animals used for experimental and other scientific purposes, EU Commission Recommendation 2007/526/EC and the fulfilment of Article 33 of EU Directive 2010/63, both concerning the housing and care of experimental animals. The recommendations provide guidance on best practices and ranges of husbandry parameters within which zebrafish welfare, as well as reproducibility of experimental procedures, are assured. Husbandry procedures found today in zebrafish facilities are numerous.

The Nordic Zebrafish and Husbandry Meeting 2018.

The Nordic zebrafish and husbandry meeting took place at Karolinska Institutet in Stockholm, November 7-9, 2018. More than 120 scientists from Europe joined this meeting, which also attracted world-leading keynote speakers such as Zoltan Varga, Didier Stainier, and Hernán Lopez-Schier. The meeting comprised both scientific as well as zebrafish husbandry and animal welfare sessions.

Gamma radiation induces locus specific changes to histone modification enrichment in zebrafish and Atlantic salmon.

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.

Ionizing radiation induces transgenerational effects of DNA methylation in zebrafish.

Ionizing radiation is known to cause DNA damage, yet the mechanisms underlying potential transgenerational effects of exposure have been scarcely studied. Previously, we observed effects in offspring of zebrafish exposed to gamma radiation during gametogenesis. Here, we hypothesize that these effects are accompanied by changes of DNA methylation possibly inherited by subsequent generations.

Gamma irradiation during gametogenesis in young adult zebrafish causes persistent genotoxicity and adverse reproductive effects.

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.

Parental exposure to gamma radiation causes progressively altered transcriptomes linked to adverse effects in zebrafish offspring.

Ionizing radiation causes a variety of effects, including DNA damage associated to cancers. However, the effects in progeny from irradiated parents is not well documented. Using zebrafish as a model, we previously found that parental exposure to ionizing radiation is associated with effects in offspring, such as increased hatching rates, deformities, increased DNA damage and reactive oxygen species.

Parental gamma irradiation induces reprotoxic effects accompanied by genomic instability in zebrafish (Danio rerio) embryos.

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 Co 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.

Dose-dependent effects of gamma radiation on the early zebrafish development and gene expression.

Ionizing radiation from natural sources or anthropogenic activity has the potential to cause oxidative stress or genetic damage in living organisms, through the ionization and excitation of molecules and the subsequent production of free radicals and reactive oxygen species (ROS). The present work focuses on radiation-induced biological effects using the zebrafish (Danio rerio) vertebrate model. Changes in developmental traits and gene expression in zebrafish were assessed after continuous external gamma irradiation (0.

Differential DNA methylation at conserved non-genic elements and evidence for transgenerational inheritance following developmental exposure to mono(2-ethylhexyl) phthalate and 5-azacytidine in zebrafish.

Background: Exposure to environmental stressors during development may lead to latent and transgenerational adverse health effects. To understand the role of DNA methylation in these effects, we used zebrafish as a vertebrate model to investigate heritable changes in DNA methylation following chemical-induced stress during early development. We exposed zebrafish embryos to non-embryotoxic concentrations of the biologically active phthalate metabolite mono(2-ethylhexyl) phthalate (MEHP, 30 µM) and the DNA methyltransferase 1 inhibitor 5-azacytidine (5AC, 10 µM).

Parental exposure to natural mixtures of persistent organic pollutants (POP) induced changes in transcription of apoptosis-related genes in offspring zebrafish embryos.

Apoptosis is an integral element of development that may also be initiated by environmental contaminants. The aim of the present study was to assess potential changes in the regulation of apoptotic genes in zebrafish embryos following parental exposure to two natural mixtures of persistent organic pollutants (POP). The mixture from Lake Mjøsa contained exceptionally high concentrations of polybrominated diphenyl ethers (PBDE), as well as relatively high levels of polychlorinated biphenyls (PCB) and dichlorodiphenyltrichloroethane (DDT).

Endocrine effects of real-life mixtures of persistent organic pollutants (POP) in experimental models and wild fish.

A series of studies have assessed the occurrence, levels, and potential adverse effects of persistent organic pollutants (POP) in fish from Lake Mjøsa. In this lake, high levels of various POP were detected in biota. Fish from the nearby Lake Losna contain background levels of POP and served as reference (controls) in these studies.

European Zebrafish Meeting 2015 Husbandry Session Report.

A workshop to address husbandry and animal welfare was held during the 9th European Zebrafish Meeting in Oslo, Norway, from June 28 to July 2, 2015. The husbandry workshop took place on Monday, June 29, and was well attended by ∼100 audience members. It highlighted problems arising from the diversity of current husbandry practices and included presentations on recent efforts to find common husbandry and animal welfare standards from a variety of international contributors, from Norway, Portugal, the United Kingdom, as well as the United States and Japan.

Effects of microgravity simulation on zebrafish transcriptomes and bone physiology-exposure starting at 5 days post fertilization.

Physiological modifications in near weightlessness, as experienced by astronauts during space flight, have been the subject of numerous studies. Various animal models have been used on space missions or in microgravity simulation on ground to understand the effects of gravity on living animals. Here, we used the zebrafish larvae as a model to study the effect of microgravity simulation on bone formation and whole genome gene expression.

Fish from Head to Tail: The 9th European Zebrafish Meeting in Oslo.

The 9th European Zebrafish Meeting took place recently in Oslo (June 28-July 2, 2015). A total of 650 participants came to hear the latest research news focused on the zebrafish, Danio rerio, and to its distant evolutionary relative medaka, Oryzias latipes. The packed program included keynote and plenary talks, short oral presentations and poster sessions, workshops, and strategic discussions.

Zebrafish Bone and General Physiology Are Differently Affected by Hormones or Changes in Gravity.

Teleost fish such as zebrafish (Danio rerio) are increasingly used for physiological, genetic and developmental studies. Our understanding of the physiological consequences of altered gravity in an entire organism is still incomplete. We used altered gravity and drug treatment experiments to evaluate their effects specifically on bone formation and more generally on whole genome gene expression.

Dynamics of DNA hydroxymethylation in zebrafish.

During embryonic development in mammals, most of the methylated cytosines in the paternal genome are converted to 5-hydroxymethyldeoxycytidine (hmC), as part of DNA methylation reprogramming. Recent data also suggest tissue-specific functional roles of hmC, perhaps as an epigenetic mark. However, limited data are available on the levels and tissue distribution in zebrafish.

The specific alteration of histone methylation profiles by DZNep during early zebrafish development.

Early embryo development constitutes a unique opportunity to study acquisition of epigenetic marks, including histone methylation. This study investigates the in vivo function and specificity of 3-deazaneplanocin A (DZNep), a promising anti-cancer drug that targets polycomb complex genes. One- to two-cell stage embryos were cultured with DZNep, and subsequently evaluated at the post-mid blastula transition stage for H3K27me3, H3K4me3 and H3K9me3 occupancy and enrichment at promoters using ChIP-chip microarrays.

Zebrafish as a model to study the role of DNA methylation in environmental toxicology.

Environmental epigenetics is a rapidly growing field which studies the effects of environmental factors such as nutrition, stress, and exposure to compounds on epigenetic gene regulation. Recent studies have shown that exposure to toxicants in vertebrates is associated with changes in DNA methylation, a major epigenetic mechanism affecting gene transcription. Zebra fish, a well-known model in toxicology and developmental biology, are emerging as a model species in environmental epigenetics despite their evolutionary distance to rodents and humans.

Normalization of RNA-sequencing data from samples with varying mRNA levels.

Methods for normalization of RNA-sequencing gene expression data commonly assume equal total expression between compared samples. In contrast, scenarios of global gene expression shifts are many and increasing. Here we compare the performance of three normalization methods when polyA(+) RNA content fluctuates significantly during zebrafish early developmental stages.

Transcriptome dynamics and diversity in the early zebrafish embryo.

Recent years advances in high-throughput sequencing have improved our understanding of how transcripts regulate early vertebrate development. Here, we review the transcriptome dynamics and diversity during early stages of zebrafish embryogenesis. Transcriptome dynamics is characterized by different patterns of mRNA degradation, activation of dormant transcripts and onset of transcription.