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Cellular and physiological strategies of a marine microalga during polar night

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Published on 26 March 2021
Project summary
Microalgae in the oceans are pivotal for the carbon cycle, atmospheric oxygen and trophic networks. These single-celled photosynthetic organisms constantly face environmental variations (nutrients and light), and their physiological responses determine ecosystem functioning. In polar regions, the survival of microalgae in prolonged darkness during the polar night is one of the most intriguing physiological phenomena. These productive regions are important for carbon sequestration but are facing perturbations due to climate change. The microalga Phaeocystis antarctica is an important primary producer in the Antarctic (i.e. 60 % of the primary production). This microalga survives long periods of darkness (e.g. 5 months). During the austral spring, the microalga resumes growth and photosynthesis and can form massive blooms. Because of logistical difficulties that prevent winter sampling in these regions, our knowledge on the physiology and cellular adaptation of this microalga in polar night/day remain very limited. Here, we propose to simulate the winter-spring transition in the laboratory and investigate the photo-physiology and metamorphosis of the microalga Phaeocystis antarctica that we maintain in culture. The student will measure different photosynthetic parameters (collab. with LPM) and quantify carbon fixation in light/dark transitions. In parallel, she/he will reconstruct in 3D the cellular architecture of microalgae using FIB-SEM (collab. with MEM and IBS), with a focus on the morphometrics (volume, surface) of mitochondria, plastids (thylakoids and pyrenoid), and carbon reserves. This will be also carried out on natural free-living Phaeocystis cells collected in the Antarctic by the Tara-Oceans expedition. To identify underpinning molecular players, he/she will search for gene homologs involved in chloroplast biogenesis at dark/light transition in plants (e.g. photoreceptors, PEP) and quantify their activity (collab. with ChromDev). The candidate will be trained to photophysiology, 3D image analysis and molecular methods and will benefit from a collaborative network at IRIG.

Host laboratory
Photosymbiosis team.

Polar microalga, cellular architecture, plastid metamorphosis.

Johan Decelle
Robert Blanvillain ChromDev Team

Call for students applications. Academic year 2021-2022

In the framework of the Chemistry Biology Health (CBH) Graduate School of Université Grenoble Alpes, the GRAL research programme funds MSc (Master 2) research scholarships.

We seek motivated candidates planning to:

attend one of the following Master programmes (2nd year MSc / Master 2 / M2) at Université Grenoble Alpes (taught in English):
Master in Biology:
Structural Biology of Pathogens
Immunology, Microbiology, Infectious Diseases
Neurobiology, Neurosciences
Physiology, Epigenetics Development, Cell Differentiation

Master in Plant Biology:
PLANTA International

& do a research internship in Integrated & Structural Cell Biology at one of the labs associated with the GRAL programme in Grenoble: IBS, PCV, BS, and CBM.

A maximum of 6 GRAL scholarships of 8 000 € are offered to cover the academic year from September 2021 to June 2022, which includes 4 months of courses and 6 months of research internship.

The call is open to EU and non-EU students.

The candidates must send their application in a unique pdf file to anne-mathilde.thierry _at_ (e-mail subject: M2-2021-LastName) before May 14th 2021 (23:59, CET), including:

A cover letter indicating the selected MSc programme at Université Grenoble Alpes, and 2 choices (ranked) for the 6-month research internship project
Diplomas and copies of academic transcripts for the last 2 academic years (translated to French or English if appropriate)
For non-native English speakers, level of language proficiency (e.g. TOEIC, Bulats, etc.)
One letter of recommendation
E-candidate portal application number

We strongly recommend that the candidates take contact with the potential supervisor(s) for the research project(s) of interest.

The applications will be evaluated by a selection committee composed of representatives of the GRAL Directory and the Master programmes.

The scholarship is conditional to the registration to one of the above programmes of the master’s degree in Biology of Université Grenoble Alpes, and to the recipient maintaining a satisfactory academic record in the programme. The admission to a 2nd year MSc programme (M2) at Université Grenoble Alpes is fully independent of the GRAL Scholarship. Application deadlines may differ between the different programmes. See admission requirements on Université Grenoble Alpes’s website:


Opening of the call for applications: March 1st 2021
Applications must be submitted by May 14th 2021
Results: June 2021

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