How Model Organisms and Model Uncertainty Impact Our Understanding of the Risk of Sublethal Impacts of Toxicants to Survival and Growth of Ecologically Relevant Species.

Understanding how sublethal impacts of toxicants affect population-relevant outcomes for organisms is challenging. We tested the hypotheses that the well-known sublethal impacts of methylmercury (MeHg) and a polychlorinated biphenyl (PCB126) would have meaningful impacts on cohort growth and survival in yellow perch (Perca flavescens) and Atlantic killifish (Fundulus heteroclitus) populations, that inclusion of model uncertainty is important for understanding the sublethal impacts of toxicants, and that a model organism (zebrafish Danio rerio) is an appropriate substitute for ecologically relevant species (yellow perch, killifish). Our simulations showed that MeHg did not have meaningful impacts on growth or survival in a simulated environment except to increase survival and growth in low mercury exposures in yellow perch and killifish.

Bringing Real Inquiry-Based Science to Diverse Secondary Educational Environments: A Virtual Zebrafish Laboratory to Investigate Environmental Health.

The goal of the University of Wisconsin-Milwaukee WInSTEP SEPA program is to provide valuable and relevant research experiences to students and instructors in diverse secondary educational settings. Introducing an online experience allows the expansion of a proven instructional research program to a national scale and removes many common barriers. These can include lack of access to zebrafish embryos, laboratory equipment, and modern classroom facilities, which often deny disadvantaged and underrepresented students from urban and rural school districts valuable inquiry-based learning opportunities.

Altered Larval Yellow Perch Swimming Behavior Due to Methylmercury and PCB126 Detected Using Hidden Markov Chain Models.

Fish swimming behavior is a commonly measured response in aquatic ecotoxicology because behavior is considered a whole organism-level effect that integrates many sensory systems. Recent advancements in animal behavior models, such as hidden Markov chain models (HMM), suggest an improved analytical approach for toxicology. Using both new and traditional approaches, we examined the sublethal effects of PCB126 and methylmercury on yellow perch (YP) larvae () using three doses.

Mitigative effects of natural and model dissolved organic matter with different functionalities on the toxicity of methylmercury in embryonic zebrafish.

Dissolved organic matter (DOM) occurs ubiquitously in aquatic environments and plays an intrinsic role in altering the chemical speciation and toxicity of methylmercury (MeHg). However, interactions between MeHg and natural DOM remain poorly understood, especially at the functional group level. We report here the mitigative effects of three natural organic matter (NOM) and five model-DOM under different concentrations (0, 1, 3, 10, 30 and 100 mg-C/L) on the toxicity of MeHg in embryonic zebrafish (<4 h post-fertilization, hpf).

Female reproductive impacts of dietary methylmercury in yellow perch (Perca flavescens) and zebrafish (Danio rerio).

The purpose of this study was to evaluate the effects of environmentally relevant dietary MeHg exposures on adult female yellow perch (Perca flavescens) and female zebrafish (Danio rerio) ovarian development and reproduction. Yellow perch were used in the study for their socioeconomic and ecological importance within the Great Lakes basin, and the use of zebrafish allowed for a detailed analysis of the molecular effects of MeHg following a whole life-cycle exposure. Chronic whole life dietary exposure of F zebrafish to MeHg mimics realistic wildlife exposure scenarios, and the twenty-week adult yellow perch exposure (where whole life-cycle exposures are difficult) captures early seasonal ovarian development.

Developmental Methylmercury Exposure Affects Swimming Behavior and Foraging Efficiency of Yellow Perch () Larvae.

Methylmercury (MeHg) is a pervasive and ubiquitous environmental neurotoxicant within aquatic ecosystems, known to alter behavior in fish and other vertebrates. This study sought to assess the behavioral effects of developmental MeHg exposure on larval yellow perch ()-a nonmodel fish species native to the Great Lakes. Embryos were exposed to MeHg (0, 30, 100, 300, and 1000 nM) for 20 h and then reared to 25 days post fertilization (dpf) for analyses of spontaneous swimming, visual motor response (VMR), and foraging efficiency.

Mercury-induced epigenetic transgenerational inheritance of abnormal neurobehavior is correlated with sperm epimutations in zebrafish.

Methylmercury (MeHg) is a ubiquitous environmental neurotoxicant, with human exposures predominantly resulting from fish consumption. Developmental exposure of zebrafish to MeHg is known to alter their neurobehavior. The current study investigated the direct exposure and transgenerational effects of MeHg, at tissue doses similar to those detected in exposed human populations, on sperm epimutations (i.

Maternal methylmercury from a wild-caught walleye diet induces developmental abnormalities in zebrafish.

Maternal methylmercury (MeHg) exposure from a contaminated diet causes adverse effects in offspring, but the underlying mechanism(s) remains unclear. In the present study, we investigated the effects of maternal dietary MeHg-exposure on the offspring, using the zebrafish (Danio rerio) as a model system. Female zebrafish were exposed to MeHg (0.

The Nicotine-Evoked Locomotor Response: A Behavioral Paradigm for Toxicity Screening in Zebrafish (Danio rerio) Embryos and Eleutheroembryos Exposed to Methylmercury.

This study is an adaptation of the nicotine-evoked locomotor response (NLR) assay, which was originally utilized for phenotype-based neurotoxicity screening in zebrafish embryos. Zebrafish embryos do not exhibit spontaneous swimming until roughly 4 days post-fertilization (dpf), however, a robust swimming response can be induced as early as 36 hours post-fertilization (hpf) by means of acute nicotine exposure (30-240μM). Here, the NLR was tested as a tool for early detection of locomotor phenotypes in 36, 48 and 72 hpf mutant zebrafish embryos of the non-touch-responsive maco strain; this assay successfully discriminated mutant embryos from their non-mutant siblings.

Parental Whole Life Cycle Exposure to Dietary Methylmercury in Zebrafish (Danio rerio) Affects the Behavior of Offspring.

Methylmercury (MeHg) is an established neurotoxicant of concern to fish-eating organisms. While most studies have focused on the fish consumers, much less is known about the effects of MeHg on the fish themselves, especially following exposures to chronic and environmentally relevant scenarios. Here we evaluated the behavioral effects of developmental MeHg insult by exposing parental generations of zebrafish to an environmentally realistic MeHg dietary concentration (1 ppm) and two higher concentrations (3 and 10 ppm) throughout their whole life span.

Understanding Genetics and Pediatric Cardiac Health.

Unlabelled: Congenital heart defects (CHD) continue to be the most prevalent birth defect that occurs worldwide in approximately 6-8 of every 1,000 live births. High rates of morbidity and mortality in infants, children, and adults living with CHD place a growing need for health care professionals (HCPs) to better understand potentially modifiable genetic and environmental influences. This paper will present examples of research and governmental initiatives that support genetics education and research and a review of known genetic factors associated with CHD development.

Wild sex in zebrafish: loss of the natural sex determinant in domesticated strains.

Sex determination can be robustly genetic, strongly environmental, or genetic subject to environmental perturbation. The genetic basis of sex determination is unknown for zebrafish (Danio rerio), a model for development and human health. We used RAD-tag population genomics to identify sex-linked polymorphisms.

Histopathologic alterations associated with global gene expression due to chronic dietary TCDD exposure in juvenile zebrafish.

The goal of this project was to investigate the effects and possible developmental disease implication of chronic dietary TCDD exposure on global gene expression anchored to histopathologic analysis in juvenile zebrafish by functional genomic, histopathologic and analytic chemistry methods. Specifically, juvenile zebrafish were fed Biodiet starter with TCDD added at 0, 0.1, 1, 10 and 100 ppb, and fish were sampled following 0, 7, 14, 28 and 42 d after initiation of the exposure.

Zebrafish as a model system for environmental health studies in the grade 9-12 classroom.

Developing zebrafish embryos were used as a model system for high school students to conduct scientific investigations that reveal features of normal development and to test how different environmental toxicants impact the developmental process. The primary goal of the module was to engage students from a wide range of socio-economic backgrounds, with particular focus on underserved inner-city high schools, in inquiry-based learning and hands-on experimentation. In addition, the module served as a platform for both teachers and students to design additional inquiry-based experiments.

Engineered nanomaterials: an emerging class of novel endocrine disruptors.

Over the past decade, engineered nanomaterials (ENMs) have garnered great attention for their potentially beneficial applications in medicine, industry, and consumer products due to their advantageous physicochemical properties and inherent size. However, studies have shown that these sophisticated molecules can initiate toxicity at the subcellular, cellular, and/or tissue/organ level in diverse experimental models. Investigators have also demonstrated that, upon exposure to ENMs, the physicochemical properties that are exploited for public benefit may mediate adverse endocrine-disrupting effects on several endpoints of mammalian reproductive physiology (e.

An evolutionarily conserved mechanism of calcium-dependent neurotoxicity in a zebrafish model of fetal alcohol spectrum disorders.

Background: Fetal alcohol spectrum disorders (FASD) are a leading cause of neurodevelopmental disability. Nonhuman animal models offer novel insights into its underlying mechanisms. Although the developing zebrafish has great promise for FASD research, a significant challenge to its wider adoption is the paucity of clear, mechanistic parallels between its ethanol (EtOH) responses and those of nonpiscine, established models.

Familiar and novel reproductive endocrine disruptors: xenoestrogens, dioxins and nanoparticles.

Environmental contaminants are known to exert endocrine-disrupting effects on the reproductive axis of animals. Many of these molecules can affect steroid biosynthesis or estrogen-receptor signaling by behaving as estrogen-like molecules ("xenoestrogens"), or by exerting estrogenmodulatory effects. Exposure to some compounds has been correlated with the skewing of sex ratios in aquatic species, feminization and demasculinization of male animals, declines in human sperm counts, and overall diminution in fertility of birds, fish, and mammals.

Low-dose gold nanoparticles exert subtle endocrine-modulating effects on the ovarian steroidogenic pathway ex vivo independent of oxidative stress.

Gold nanoparticles (GNPs) have gained considerable attention for application in science and industry. However, the untoward effects of such particles on female fertility remain unclear. The objectives of this study were to (1) examine the effects of 10-nm GNPs on progesterone and estradiol-17β accumulation by rat ovaries ex vivo and (2) to identify the locus/loci whereby GNPs modulate steroidogenesis via multiple-reference gene quantitative real-time RT-PCR.

Gene expression and pathologic alterations in juvenile rainbow trout due to chronic dietary TCDD exposure.

The goal of this project was to use functional genomic methods to identify molecular biomarkers as indicators of the impact of TCDD exposure in rainbow trout. Specifically, we investigated the effects of chronic dietary TCDD exposure on whole juvenile rainbow trout global gene expression associated with histopathological analysis. Juvenile rainbow trout were fed Biodiet starter with TCDD added at 0, 0.

Differential gene expression associated with dietary methylmercury (MeHg) exposure in rainbow trout (Oncorhynchus mykiss) and zebrafish (Danio rerio).

The objective of this study was to identify and evaluate conserved biomarkers that could be used in most species of teleost fish at most life-stages. We investigated the effects of sublethal methylmercury (MeHg) exposure on developing rainbow trout and zebrafish. Juvenile rainbow trout and young adult zebrafish were fed food with MeHg added at 0, 0.

Effects of methylmercury on epigenetic markers in three model species: mink, chicken and yellow perch.

We previously reported that methylmercury (MeHg) exposure is associated with DNA hypomethylation in the brain stem of male polar bears. Here, we conveniently use archived tissues obtained from controlled laboratory exposure studies to look for evidence that MeHg can disrupt DNA methylation across taxa. Brain (cerebrum) tissues from MeHg-exposed mink (Neovison vison), chicken (Gallus gallus) and yellow perch (Perca flavescens) were analyzed for total Hg levels and global DNA methylation.

Comparison of neurobehavioral effects of methylmercury exposure in older and younger adult zebrafish (Danio rerio).

It is widely recognized that the nature and severity of responses to toxic exposure are age-dependent. Using active avoidance conditioning as the behavioral paradigm, the present study examined the effect of short-term methylmercury (MeHg) exposure on two adult age classes, 1- and 2-year-olds to coincide with zebrafish in relatively peak vs. declining health conditions.