title: Gene expression responses for detecting sublethal effects of xenobiotics and whole effluents on a Xenopus laevis embryo assay.
abstract: In the present study, the authors investigated the effects of bisphenol A, chlorpyrifos, methylparaben, and 2 effluent samples from wastewater treatment plants located in the province of Madrid, Spain, on the messenger RNA expression of specific genes involved in early development (ESR1, pax6, bmp4, and myf5) and a gene involved in the general stress response (hsp70) during Xenopus laevis embryo development. Gene expression was analyzed after 4 h, 24 h, and 96 h of exposure by semiquantitative reverse-transcriptase-polymerase chain reaction. Concentration ranges of the compounds and dilutions for the samples were selected to cause morphological alterations in embryos after 96 h of exposure. Transcript levels of ESR1, pax6, and hsp70 were differentially altered at early developmental stages with patterns specific to the contaminant and the exposure time. However, further studies are needed to establish transcript levels of specific genes as biomarkers of sublethal effects in an environmental risk-assessment framework. Besides, studies including more generic responses, such as genes encoding antioxidant enzymes, together with genes related to embryonic development have to be developed to look for a battery of mechanistic endpoints for the evaluation of chemical exposure at the molecular level in a first-tier assessment.
authors: Department of the Environment, National Institute for Agricultural and Food Research and Technology, Madrid, Spain. san-segundo.laura@inia.es
authors: Laura
authors: L
authors: San Segundo
authors: Federica
authors: F
authors: Martini
authors: M Victoria
authors: MV
authors: Pablos
mesh_terms: D000818:Animals; D001559:Benzhydryl Compounds / Q000633:toxicity; D001681:Biological Assay; D004390:Chlorpyrifos / Q000633:toxicity; D004625:Embryo, Nonmammalian / Q000002:abnormalities / Q000187:drug effects / Q000378:metabolism; D047108:Embryonic Development / Q000187:drug effects* / Q000235:genetics; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D010226:Parabens / Q000633:toxicity; D010636:Phenols / Q000633:toxicity; D012333:RNA, Messenger / Q000378:metabolism; D013030:Spain; D013997:Time Factors; D062065:Wastewater / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015262:Xenobiotics / Q000633:toxicity*; D014982:Xenopus laevis; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D004390:Chlorpyrifos; D010226:Parabens; D010636:Phenols; D012333:RNA, Messenger; D062065:Wastewater; D014874:Water Pollutants, Chemical; D015262:Xenobiotics; C015358:methylparaben; C006780:bisphenol A; D000098826:Bisphenol A Compounds
keywords: Developmental toxicity; Gene expression; Wastewater treatment plant effluent; Xenopus laevis