Missions

The postdoctoral researcher will develop a research project aimed at assessing the effects of microplastics (MPs) on early development and thyroid physiology in a model aquatic vertebrate, the amphibian Xenopus laevis. The main missions will be:

To conduct and analyze exposure experiments of blastulas/embryos to polyethylene (PE) MPs of different sizes (nano: 200 nm; micro: 5 µm), including fluorescent ones, in order to study their uptake kinetics and their accumulation in tissues and organs.

To evaluate the impact of these MPs on thyroid function using the regulatory XETA assay (TG 248), developed and mastered in the laboratory, on transgenic lines. An additional study on neuronal and oligodendrocyte development is planned.

To analyze the long-term effects of developmental exposure up to the critical metamorphosis stage.

To assess the carrier effect of MPs through co-exposure with plasticizers known to have endocrine-disrupting effects.

The candidate will be involved in writing scientific articles and presenting results at conferences.

Activités

The postdoctoral researcher will be responsible for the culture and maintenance of the amphibian model Xenopus laevis (wild-type and transgenic lines). He/she will design and carry out developmental exposure protocols to microplastics. He/she will use the advanced imaging techniques available, including confocal microscopy for tracking fluorescent MPs and developmental analyses, as well as Scanning Electron Microscopy (SEM) available at the MNHN site. He/she will perform molecular and cellular analyses such as RNA extraction, RT-qPCR, and immunohistochemistry on embryonic and larval tissues. Behavioral analyses related to developmental stages and metamorphosis will also be conducted. Close collaboration with partners (IPREM, CNRS-UPPA, Pau; Plastic@Sea, Banyuls) will be essential for quantitative and qualitative analyses of MPs in biological samples and exposure media.

Compétences

A PhD in developmental biology, ecotoxicology, endocrinology, or a related field is required. Solid experience in vertebrate developmental biology, as well as a strong command of basic molecular and cellular biology techniques (PCR, immunohistochemistry) are expected. An affinity for bioinformatics analyses is a plus. Experience in imaging (confocal) and/or particle manipulation (nanoparticles, microplastics) constitutes a major asset. Knowledge in thyroid physiology/endocrinology and neuroendocrinology is appreciated. The candidate must demonstrate autonomy, experimental rigor, and strong scientific writing skills in English. The ability to work in a team and coordinate collaborations is essential. Supervisory work with an intern is anticipated.

Contexte de travail

The position is funded for a full-time basis over an initial period of 18 months. The postdoctoral fellow will be integrated into the RodEO team within the PhyMA research unit (Molecular Physiology and Adaptation), a Joint Research Unit of the National Museum of Natural History (MNHN) associated with the CNRS (UMR 7221). The unit, located in the Jardin des Plantes in Paris, offers a stimulating scientific environment and state-of-the-art technical platforms (amphibian animal facility, confocal microscopy, access to SEM, CT scan).

Contraintes et risques

Working with a model organism requiring authorization for an experimental project (in accordance with current regulations on animal experimentation, mandatory training level required). Handling of chemicals and synthetic particles. Refer to appropriate safety protocols. Flexibility is required for certain long-duration experiments (developmental monitoring).

Informations complémentaires

Applications (detailed CV, cover letter, and contact information for 2 referees) must be submitted before January 10, 2026.