RESUMEN
Sites along the Elizabeth River are contaminated with polycyclic aromatic hydrocarbons (PAHs) from historical creosote production and other industrial processes. Previous studies have demonstrated that Atlantic killifish collected from sites throughout the Elizabeth River display resistance to the teratogenic effects of PAH-exposure in a manner commensurate with sediment PAH concentrations. The current study characterized various chemical pollutants in sediment and investigated the effects of aqueous sediment extracts from sites along the Elizabeth River to the cardiac development of Atlantic killifish embryos from fish collected from an uncontaminated reference site. Embryonic cardiac deformities were more prevalent after exposure to extracts from sites with high PAH loads. However, activation of cytochrome P4501A, a gene up-regulated by PAH-induction of the aryl hydrocarbon receptor and measured using an in ovo EROD assay, did not consistently increase with PAH concentrations. This work further characterizes sediments in the Elizabeth River, as well as provides insight into the evolutionary pressures at each ER site.
Asunto(s)
Fundulidae/fisiología , Sedimentos Geológicos/química , Hidrocarburos Policíclicos Aromáticos/toxicidad , Contaminantes Químicos del Agua/toxicidad , Animales , Embrión no Mamífero/efectos de los fármacos , Metales/toxicidad , Bifenilos Policlorados/toxicidad , Ríos , VirginiaRESUMEN
Anthropogenic stressors, including pollutants, are key evolutionary drivers. It is hypothesized that rapid evolution to anthropogenic changes may alter fundamental physiological processes (e.g., energy metabolism), compromising an organism's capacity to respond to additional stressors. The Elizabeth River (ER) Superfund site represents a "natural-experiment" to explore this hypothesis in several subpopulations of Atlantic killifish that have evolved a gradation of resistance to a ubiquitous pollutant-polycyclic aromatic hydrocarbons (PAH). We examined bioenergetic shifts and associated consequences in PAH-resistant killifish by integrating genomic, physiological, and modeling approaches. Population genomics data revealed that genomic regions encoding bioenergetic processes are under selection in PAH-adapted fish from the most contaminated ER site and ex vivo studies confirmed altered mitochondrial function in these fish. Further analyses extending to differentially PAH-resistant subpopulations showed organismal level bioenergetic shifts in ER fish that are associated with increased cost of living, decreased performance, and altered metabolic response to temperature stress-an indication of reduced thermal plasticity. A movement model predicted a higher energetic cost for PAH-resistant subpopulations when seeking an optimum habitat. Collectively, we demonstrate that pollution adaption and inhabiting contaminated environments may result in physiological shifts leading to compromised organismal capacity to respond to additional stressors.
Asunto(s)
Adaptación Fisiológica , Fundulidae/fisiología , Hidrocarburos Policíclicos Aromáticos/toxicidad , Contaminantes Químicos del Agua/toxicidad , Animales , Metabolismo Energético , RíosRESUMEN
The use of antibacterial silver nanomaterials in consumer products ranging from textiles to toys has given rise to concerns over their environmental toxicity. These materials, primarily nanoparticles, have been shown to be toxic to a wide range of organisms; thus methods and materials that reduce their environmental toxicity while retaining their useful antibacterial properties can potentially solve this problem. Here we demonstrate that silver nanocubes display a lower toxicity toward the model plant species Lolium multiflorum while showing similar toxicity toward other environmentally relevant and model organisms (Danio rerio and Caenorhabditis elegans) and bacterial species (Esherichia coli, Bacillus cereus, and Pseudomonas aeruginosa) compared to quasi-spherical silver nanoparticles and silver nanowires. More specifically, in the L. multiflorum experiments, the roots of silver nanocube treated plants were 5.3% shorter than the control, while silver nanoparticle treated plant roots were 39.6% shorter than the control. The findings here could assist in the future development of new antibacterial products that cause less environmental toxicity after their intended use.