RESUMEN
The ability to restore tissue function and morphology after injury is a key advantage of many fish for a greater chance of survival. The tissue regeneration process is regulated by multiple pathways, and it can therefore be hypothesized that environmental contaminants targeting components of these signaling pathways, may disrupt the fish's capability to repair or regenerate. This could lead to higher mortality and eventually even to a decline in populations. In this study, the effects of 17αethinylestradiol (EE2), a synthetic estrogen, were assessed on the regenerative capacity of larval zebrafish. Zebrafish aged 2â¯hour post fertilization (hpf) were exposed to 1, 10, or 100â¯ng/L EE2, and the caudal fins were amputated at 72â¯hpf. It was found that EE2 exposure significantly inhibited fin regeneration and changed locomotor behavior. The transcription levels for most of the genes involved in the signaling networks regulating the fin regeneration, such as axin2, fgfr1, bmp2b and igf2b, were down-regulated in the amputated fish in response to EE2 exposure, which was in contrast to their increased patterns in the vehicle-exposed control fish. Additionally, the mRNA levels of several immune-related genes, such as il-1ß, il-6, il-10 and nf-κb2, were significantly decreased after EE2 exposure, accompanied by a lower density of neutrophils migrated into the wound site. In conclusion, the present study indicated for the first time that estrogenic endocrine disrupting chemicals (EEDCs) could inhibit the regenerative capacity of zebrafish, and this effect was speculated to be mediated through the alteration in regeneration-related signaling pathways and immune competence. This work expands our knowledge of the potential effects of EEDCs on injured aquatic organisms, and highlights the ecotoxicological significance of relationships between regenerative process and endocrine system. This study also implies the potential application of fin regeneration assay for assessing immunotoxicity in ecotoxicological risk assessment.
Asunto(s)
Aletas de Animales/fisiología , Disruptores Endocrinos/efectos adversos , Etinilestradiol/efectos adversos , Regeneración/efectos de los fármacos , Contaminantes Químicos del Agua/efectos adversos , Pez Cebra/fisiología , Aletas de Animales/efectos de los fármacos , Aletas de Animales/cirugía , Animales , Movimiento Celular/efectos de los fármacos , Inmunidad Innata/efectos de los fármacos , Inmunidad Innata/genética , Leucocitos/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Transcripción Genética/efectos de los fármacos , Pez Cebra/cirugíaRESUMEN
The frequency and intensity of cyanobacterial blooms are increasing worldwide with major societal and economic costs. Interactions between toxic cyanobacteria and eukaryotic algal competitors can affect toxic bloom formation, but the exact mechanisms of interspecies interactions remain unknown. Using metabolomic and proteomic profiling of co-cultures of the toxic cyanobacterium Microcystis aeruginosa with a green alga as well as of microorganisms collected in a Microcystis spp. bloom in Lake Taihu (China), we disentangle novel interspecies allelopathic interactions. We describe an interspecies molecular network in which M. aeruginosa inhibits growth of Chlorella vulgaris, a model green algal competitor, via the release of linoleic acid. In addition, we demonstrate how M. aeruginosa takes advantage of the cell signaling compound nitric oxide produced by C. vulgaris, which stimulates a positive feedback mechanism of linoleic acid release by M. aeruginosa and its toxicity. Our high-throughput system-biology approach highlights the importance of previously unrecognized allelopathic interactions between a broadly distributed toxic cyanobacterial bloom former and one of its algal competitors.
Asunto(s)
Alelopatía/fisiología , Chlorella vulgaris/fisiología , Ácido Linoleico/farmacología , Microcystis/efectos de los fármacos , Microcystis/fisiología , Óxido Nítrico/farmacología , Técnicas de Cocultivo , Cianobacterias/crecimiento & desarrollo , ProteómicaRESUMEN
Because brominated flame retardants are being banned or phased out worldwide, organophosphate flame retardants have been used as alternatives on a large scale and have thus become ubiquitous environmental contaminants; this raises great concerns about their environmental health risk and toxicity. Considering that previous research has identified the nervous system as a sensitive target, Japanese medaka were used as an aquatic organism model to evaluate the developmental neurotoxicity of 4 organophosphate flame retardants: triphenyl phosphate, tri-n-butyl phosphate, tris(2-butoxyethyl) phosphate, and tris(2-chloroethyl) phosphate (TCEP). The embryo toxicity test showed that organophosphate flame retardant exposure could decrease hatchability, delay time to hatching, increase the occurrence of malformations, reduce body length, and slow heart rate. Regarding locomotor behavior, exposure to the tested organophosphate flame retardants (except TCEP) for 96 h resulted in hypoactivity for medaka larvae in both the free-swimming and the dark-to-light photoperiod stimulation test. Changes of acetylcholinesterase activity and transcriptional responses of genes related to the nervous system likely provide a reasonable explanation for the neurobehavioral disruption. Overall, the present study clearly demonstrates the developmental neurotoxicity of various organophosphate flame retardants with very different potency and contribute to the determination of which organophosphate flame retardants are appropriate substitutes, as well as the consideration of whether regulations are reasonable and required. Environ Toxicol Chem 2016;35:2931-2940. © 2016 SETAC.
Asunto(s)
Retardadores de Llama/toxicidad , Oryzias/crecimiento & desarrollo , Acetilcolinesterasa/genética , Acetilcolinesterasa/metabolismo , Animales , Tamaño Corporal/efectos de los fármacos , Embrión no Mamífero/efectos de los fármacos , Proteínas de Peces/genética , Proteínas de Peces/metabolismo , Frecuencia Cardíaca/efectos de los fármacos , Locomoción/efectos de los fármacos , Organofosfatos/toxicidad , Compuestos Organofosforados/toxicidad , Oryzias/fisiología , Pruebas de Toxicidad , Transcripción Genética/efectos de los fármacosRESUMEN
With the gradual ban on brominated flame retardants (FRs), the application of organophosphate flame retardants (OPFRs) has increased remarkably. Considering the structural similarity between OPFRs and organophosphate pesticides, hypotheses that OPFRs may interfere with neurodevelopment as organophosphate pesticides are reasonable. In this study, the neurotoxicity of three OPFRs, including tri-n-butyl phosphate (TNBP), tris (2-butoxyethyl) phosphate (TBOEP) and tris (2-chloroethyl) phosphate (TCEP), was evaluated in zebrafish larvae and then compared with the neurotoxicity of organophosphate pesticide chlorpyrifos (CPF). The results showed that similar to CPF, exposure to OPFRs for 5days resulted in significant changes in locomotor behavior, either in free swimming or in photomotor response. However, given the transcriptional changes that occur in nervous system genes in response to OPFRs and CPF, as well as the altered enzyme activity of AChE and its mRNA level, the underlying mechanisms for neurotoxicity among these organophosphate chemicals might be varied. In summary, the results confirm the potential neurodevelopmental toxicity of OPFRs and underscore the importance of identifying the mechanistic targets of the OPFRs with specific moieties. Furthermore, as the neurobehavioral responses are well conserved among vertebrates and the exposure of children to OPFRs is significant, a thorough assessment of the risk of OPFRs exposure during early development should be highly emphasized in future studies.
Asunto(s)
Conducta Animal/efectos de los fármacos , Retardadores de Llama/toxicidad , Insecticidas/toxicidad , Organofosfatos/toxicidad , Efectos Tardíos de la Exposición Prenatal/metabolismo , Efectos Tardíos de la Exposición Prenatal/psicología , Acetilcolinesterasa/metabolismo , Animales , Cloropirifos/toxicidad , Femenino , Compuestos Organofosforados/toxicidad , Fosfinas/toxicidad , Embarazo , Natación , Transcripción Genética/efectos de los fármacos , Pez Cebra/genética , Pez Cebra/fisiologíaRESUMEN
ß-Agonists, which are used as human pharmaceuticals or feed additives, have been detected in aquatic environments. ß-Agonists have also been proposed for use in aquaculture. However, there are limited data available regarding the adverse effects of ß-agonists in aquatic organisms. In this study, ractopamine was selected as the representative ß-agonist, and medaka embryos were exposed at concentrations ranging from 5 to 625 µg/L for 44 days. In contrast to what has been found in mammals, ractopamine caused no growth response in medaka. However, the transcriptional changes of genes related to the hypothalamic-pituitary-gonadal (HPG) axis, especially in females, suggested that ß-agonists may have the potential to disrupt the endocrine system. Moreover, genes involved in anti-oxidative activity or detoxification were affected in a gender-specific manner. These findings, particularly the effects on the endocrine system of fish, will advance our understanding of the ecotoxicity of ß-agonists.