Supervisors: 

• Hélène Licandro (helene.licandro(at)agrosupdijon.fr) 
• Eric Neyraud (eric.neyraud(at)inrae.fr)

Duration: 5 to 6 months (January to June 2025, with flexibility)

Lab: 

AFIM team, UMR PAM, l’Institut Agro Dijon, France (https://umr-pam.fr/en/our-teams/food-fermentation-interaction-microbiota-afim)

The internship will be conducted within the AFIM team of the UMR PAM, in collaboration with the FFOPP team of the UMR CSGA (https://www2.dijon.inrae.fr/csga/site_engl/equipe_1.php)

Application process:

Please send the following documents to helene.licandro(at)agrosupdijon.fr: 

• CV

• cover letter

• letter(s) of recommendation or contact details of previous internship supervisors.

Context and objectives:

The oral cavity experiences a significant influx of microorganisms, particularly lactic acid bacteria (LAB), during the consumption of fermented foods. However, the interactions between the oral cavity and LAB remain underexplored. In a study using a rat model, we demonstrated a considerable interindividual variability in the persistence of LAB in the hours following the consumption of fermented food (1-3). Our ongoing research indicates that certain variations in salivary biochemistry are correlated with LAB persistence in this rat model, thus partially explaining this variability. Furthermore, we have also found associations between taste perception and the composition of the oral microbiota (4, 5). The activity of LAB in the mouth has not yet been evaluated. Active LAB from fermented foods could directly modulate oral biology, including sensory perception. They also could modulate the oral microbiota, which could, in turn, affect sensory perception.

During this internship, the student will investigate the interaction between LAB and human saliva by exploring LAB activities in relation to the biological properties of saliva. The research may involved a variety of methodologies such as chromogenic or fluorescent probes, enzymatic activity assays, targeted gene expression analysis, microscopy, and cloning techniques.

This project offers a unique opportunity to deepen our understanding of LAB in the oral cavity and their impact on sensory perception, with potential applications in improving the quality of life for individuals with eating behaviour disorders. The project is funded by the French National Research Agency (ANR) and may be extended into a PhD opportunity.

Desired Skills and Qualifications:

• Final-year Master’s student or equivalent (e.g., engineering school)

• Strong background in microbiology, biochemistry, or a related field

• Experience with laboratory techniques such as culture of microorganisms, enzymatic assays, microscopy, and molecular biology

• Ability to quickly become autonomous and reliable in conducting experiments

• Proficiency in researching and analysing scientific literature, particularly methodological information

• Analytical thinking and problem-solving abilities

• Good communication skills and ability to work collaboratively

References:

1. Ibarlucea-Jerez M, Monnoye M, Chambon C, Gerard P, Licandro H, Neyraud E. 2024. Fermented food consumption modulates the oral microbiota. NPJ Sci Food 8:55.

2. Ibarlucea-Jerez M, Canivenc-Lavier MC, Beuvier E, Barbet P, Menetrier F, Neyraud E, Licandro H. 2022. Persistence of fermented food bacteria in the oral cavity of rats after one week of consumption. Food Microbiol 107:104087.

3. Ibarlucea-Jerez M. 2022. Persistence of lactic acid bacteria from fermented foods in the oral cavity of rats, potential links with oral microbiota, salivary composition and taste perception. PhD. thesis. Université Bourgogne Franche-Comté.

4. Feng Y, Licandro H, Martin C, Septier C, Zhao M, Neyraud E, Morzel M. 2018. The Associations between Biochemical and Microbiological Variables and Taste Differ in Whole Saliva and in the Film Lining the Tongue. Biomed Res Int 2018:2838052.

5. Licandro H, Truntzer C, Fromentin S, Morabito C, Quinquis B, Pons N, Martin C, Blottiere HM, Neyraud E. 2023. The bacterial species profiles of the lingual and salivary microbiota differ with basic tastes sensitivity in human. Sci Rep 13:20339.