Missions

Photosynthesis is arguably the most biologically important process on Earth. The conversion of light into chemically useful energy is essential for virtually all life, either directly (photosynthetic organisms) or indirectly (herbivores and their predators). It also largely sustains human activities via the combustion of fossil fuels.
While light is one of the substrates for carbon reduction, plants and photosynthetic microbes often find themselves in a situation of excess excitation. A plethora of short- and long-term response mechanisms have evolved, including several types of excess energy dissipation, facilitating the plant-light interaction. Nonetheless, despite their presence, light leads to the destruction of the photosynthetic apparatus and a decrease in photosynthetic performance. This process is called photoinhibition. Notably, upon photoinhibition, the multimeric pigment-protein complex that produces all oxygen on Earth, Photosystem II (PSII), becomes damaged in several ways.
Given the phenomenal variability of the light-harvesting antenna across photosynthetic phyla, to date it has not been possible to compare the rates of photoinhibition at constant absorbed photon flux. We have recently developed methods that allow such explorations. The aim of this project is twofold: to validate these methodologies in a number of phylogenetically unrelated microalgae, with the goal of evolutionary comparison of the PSII damage process; and secondly, to tackle singular case studies in those microalgae to unravel species-specific behavior of the PSII lifecycle.

Activités

Photosynthetic reaction centers are conserved across photosynthetic phyla, with only a single event resulting in oxygenic photosynthesis. The situation is dramatically different in terms of the light-harvesting antenna – pigment-protein complexes that surround reaction centers to increase their light absorption rate. Depending on the organism, the pigment type, their absorption spectrum, location of the antenna, and presence of photoprotective mechanisms vary strongly, providing a selective advantage for every environmental niche. Due to these differences and optical properties of the samples, identical light – even monochromatic – does not result in comparable Photosystem II rates, thus making photoinhibition resistance comparisons between species impossible.
We have recently developed a method to normalize actinic illumination to PSII charge separation rate using fluorescence spectroscopy. The method has the advantage of providing information that is light color-independent (and agnostic to antenna type), but requires preparing experiments directly in the spectrophotometer cuvettes. The study engineer will be tasked with validating a number of protocols in various species within the spectroscopic setup.

Activities include:
• Validation of experimental protocols for various microalgae species.
• Use of fluorescence spectroscopy to normalize actinic illumination.
• Collaboration with international researchers for complementary studies.
• Data analysis and writing scientific reports.
• Participation in team meetings and scientific discussions.

Compétences

Technical and Scientific Skills:
• Master's degree or Engineering degree in biology, biochemistry, biophysics, or related field.
• Experience in laboratory techniques, particularly in spectroscopy and biochemistry.
• Knowledge of scientific programming (Python, MATLAB) are a plus.
• Interest in transdisciplinary projects between observations and modeling.
• Scientific communication skills (written and oral) in English.
Other Skills:
• Good organizational skills.
• Ability to work in a team and collaborate with international partners.

Contexte de travail

The laboratory is located in the centre of Paris and offers a multidisciplinary environment with world-class experimental facilities and a substantial theoretical base for research work. The recruited study engineer will join the team responsible for analyzing the variability of biological systems and will work closely with international researchers.

Contraintes et risques

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Informations complémentaires

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