FrancaisEnglish (United Kingdom)
 

Responsable de publication :
Olivier Martin

Responsable éditoriale :
Rozenn Le Guyader

Administrateur de l'infoservice :
Thierry Balliau

portrait de Judith LegrandJudith LEGRAND

____________________________________________________________

Assistant professor in biomathematics and biostatistics at Université-Paris Sud
Génétique Quantitative et Évolution - Le Moulon
INRA – Université Paris-Sud – CNRS – AgroParisTech
Ferme du Moulon
91190 Gif-sur-Yvette
Phone : 33 1 69 33 23 49
E-mail : Cette adresse email est protégée contre les robots des spammeurs, vous devez activer Javascript pour la voir.

 

> Position and education

Since 2011: Assistant professor Université Paris-Sud, Génétique Quantitative et Évolution - Le Moulon

2010-2011: Post-doctoral researcher, Risk modeling and surveillance for health safety lab, Conservatoire national des Arts et Métiers and Epidemiology, Information systems, Modeling lab, INSERM-UPMC UMR-S 707, Paris - Dynamics of methicillin-resistant Staphylococcus aureus in a rehabilitation centre

2007-2010: Post-doctoral position in the MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College, London - Methodological development to characterize epidemics. Applications to anthrax and influenza.

2006-2007: Research engineer, Epidemiology, Information systems, Modeling lab, INSERM-UPMC UMR-S 707, Paris

2006: PhD in biomathematics, Université Pierre et Marie Curie, Paris - Mathematical modeling and the preparedness against bioterrorist attacks: an application to Ebola hemorrhagic fever and smallpox.

 

> Research interests

I use mathematical and statistical modelling to understand the role of adaptation in the evolution of life-history strategies and the structure of communities.

Key words: adaptation, life-history strategies, intra and inter-specific interactions, mathematical models, yeast.

 

> Current research projects

. Adaptation and life-history strategies

coll. Delphine Sicard and Thibault Nidelet (SPO, INRA), Sylvie Mélard (Ecole Polytechnique) - past student: Dorian Collot, PhD thesis, June 2018.

Adaptation of organisms to their environment relies on many phenotypic traits called life-history traits. Due to physical and biological constraints, selection cannot maximize all those traits together. Hence analyzing the evolution of several traits jointly will enhance our understanding of adaptation dynamics.

We are interested in the adaptation of the yeast Saccharomyces cerevisiae via several traits related to fermentation and respiration such as resource consumption rate, biomass yield or mortality. Two extreme life-history strategies have been identified from experimental data. We are developing models to highlight the components of fitness in a seasonal environment and to understand how the seasonality can shape the evolution of traits and their relation.

. Structure of microbial communities in natural sourdough

coll. Delphine Sicard and Elisa Michel (SPO, INRA), Xavier Doucet and Bernard Onno (Oniris) - past post-doc: Johan Ramsayer, past-student : Charlotte Urien

Microbial communities are ubiquitous across earth ecosystems. The recent –omics technics have highlighted their complex structure but very little is known about the ecological processes and the interactions between species shape their pattern. Wheat sourdough's microbial communities are relatively simple communities which can provide a useful model to study ecological processes structuring communities. Sourdough communities are composed of an assemblage of lactic acid bacteria and yeasts species, varying from one sourdough to another. With my collaborators, we are mixing experimental and theoretical approaches to understand how intra and inter-specific interactions shape the structure of the microbial communities observed in sourdough.

. Impact of maize development on the sensitivity to parasitism

coll. Laure Kaiser, François Rebaudo (EGCE, Paris-Saclay), Christine Dillmann, Adrienne Ressayre, Élodie Marchadier, Inoussa Sanane (GQE-Le Moulon)

Plants can escape herbivores either by building up defenses such as plant secondary compounds, or by shortening their life-cycle so that they become mature before herbivore attacks. In France, Lepidoptera stem borers have a two-generations/year life-cycle. In spring, adult females lay eggs on young leaves. During summer, second generation caterpillars enter plant stems and dig galleries until ears. Completion of life-cycle occurs in non-harvested cobs during winter. Among tools for biological pest controls, sowing early maize varieties is recommended because maize stems are stronger when the second-generation larvae arise and better resist invasion. We are investigating how plant phenology shifts interfere with Lepidoptera stem borers life-cycle using theoretical and experimental approaches in the field.

 

> Teaching

Licence:

. Statistical tests for biologists
. Ecology and statistics
. Modeling biological systems with ordinary differential equations
. Introduction to programming
. Co-director of the "double licence Biologie et Mathématiques" (bachelor degree in both biology and mathematics)

Master 1:

. Biostatistics

Master 2:

. Introduction to mathematical models of infectious diseases dynamics
. Introduction to statistical data analysis for optometrists and ergonomists
. Big data

 

> Publications

Collot D., Nidelet T., Ramsayer J., Martin C. O., Méléard S., Dillmann C., Sicard D., Legrand J. (2018) Feedback between environment and traits under selection in a seasonal environment: consequences for experimental evolution. Proc. R. Soc. B, 285 (1876)

Legrand J.*,  Bolotin-Fukuhara M.*, Bourgais A., Fairhead C., Sicard D. (2016) Life-history strategies and carbon metabolism gene dosage in the Nakaseomyces yeasts. FEMS Yeast Res, 16(2)

Obadia T.,  Silhol R., Opatowski L., Temime L., Legrand J., Thiébaut A.C.M. ,  Herrmann J.-L., Fleury E., Guillemot D., Boëlle P.-Y., on behalf of the I-Bird Study Group (2015)  Detailed Contact Data and the Dissemination of Staphylococcus aureus in Hospitals. Plos Computational Biology, 11(3)

Legrand J., Temime L., Lawrence C., Herrmann J. L. , Boelle P. Y. and Guillemot D., on behalf of the iBird Study Group (2015), Occupational Determinants of Methicillin-Resistant Staphylococcus aureus Colonization Among Healthcare Workers: A Longitudinal Study in a Rehabilitation Center. Infection Control and Hospital Epidemiology, 36(7).

Lhomme E., Urien C., Legrand J., Dousset X., Onno B., Sicard D. (2015), Sourdough microbial community dynamics: An analysis during French organic bread-making processes. Food Microbiology, 53(Part A)

Spor A, Kvitek DJ, Nidelet T, Martin J, Legrand J, Dillmann C, Bourgais A, de Vienne D, Sherlock G, Sicard D (2013) Phenotypic and genotypic convergences are influenced by historical contingency and environment in yeast. Evolution, 68(3)

Egan JR, Legrand J, Hall IM, Cauchemez S, Ferguson NM, Leach S (2010) Re-assessment of mitigation strategies for deliberate releases of anthrax using a real-time outbreak characterization tool. Epidemics 2:189-194

Legrand J, Egan JR, Hall IM, Cauchemez S, Leach S, Ferguson NM (2009) Estimating the location and spatial extent of a covert anthrax release. PLoS Comput Biol 5: e1000356.

Garske T, Legrand J, Donnelly CA, Ward H, Cauchemez S, et al. (2009) Assessing the severity of the novel influenza A/H1N1 pandemic. BMJ 339: b2840.

Egan JR, Legrand J, Hall IM, Cauchemez S, Ferguson NM, Leach S (2010) Re-assessment of mitigation strategies for deliberate releases of anthrax using a real-time outbreak characterization tool. Epidemics 2:189-194

Legrand J, Egan JR, Hall IM, Cauchemez S, Leach S, Ferguson NM (2009) Estimating the location and spatial extent of a covert anthrax release. PLoS Comput Biol 5: e1000356.

Garske T, Legrand J, Donnelly CA, Ward H, Cauchemez S, et al. (2009) Assessing the severity of the novel influenza A/H1N1 pandemic. BMJ 339: b2840.

Legrand J, Sanchez A, Le Pont F, Camacho L, Larouze B (2008) Modeling the impact of tuberculosis control strategies in highly endemic overcrowded prisons. PLoS One 3: e2100.

Massin L, Legrand J, Valleron AJ, Flahault A (2007) Modelling outbreak control for pneumonic plague. Epidemiol Infect 135: 733-739.

Legrand J, Grais RF, Boelle PY, Valleron AJ, Flahault A (2007) Understanding the dynamics of Ebola epidemics. Epidemiol Infect 135: 610-621.

Legrand J, Vergu E, Flahault A (2006) Real-time monitoring of the influenza vaccine field effectiveness. Vaccine 24: 6605-6611.

Le Menach A, Legrand J, Grais RF, Viboud C, Valleron AJ, et al. (2005) Modeling spatial and temporal transmission of foot-and-mouth disease in France: identification of high-risk areas. Vet Res 36: 699-712.

Legrand J, Viboud C, Boelle PY, Valleron AJ, Flahault A (2004) Modelling responses to a smallpox epidemic taking into account uncertainty. Epidemiol Infect 132

Legrand J, Flahault A (2003) Modélisation mathématique de la diffusion spatio-temporelle de la variole. Env., Risques & Santé ;2:211-219.