ANR-DFG SYMBIONT project meeting in Paris
Inria Paris
Building C, room J.L. Lions, ground level
2 rue Simone Iff
Paris 12
see Practical information (map, recommend hotel, etc.)
Registered participants:
Orianne Bargain (Saclay, France) Eléonore Bellot (Saclay, France) Aurelien Desoeuvres (Montpellier, France) François Fages (Saclay, France) Mathieu Hemery (Saclay, France) François Lemaire (Lille, France) Alexandru Losif (Aachen, Germany) Eva Philippe (Saclay, France) Adrien Poteaux (Lille, France) Ovidiu Radulescu (Montpellier, France) Jakob Ruess (Pasteur Paris, Saclay France) Mathias Seiss (Univ. Kassel, Germany) Sylvain Soliman (Saclay, France) Andreas Weber (Bonn, Germany)
Tentative schedule
April 4 2019
9.30 Coffee
10.00 Andreas Weber, Univ. Bonn
Symbiont advances, deliverables and deadlines
10.30 Ovidiu Radulescu, Montpellier
Progress report on tropical geometry inspired model analysis
11.30 coffee
12.00 Jakob Ruess, Inbio - Pasteur, Lifeware - Inria Saclay
Molecular noise of innate immunity shapes bacteria-phage ecologies
13.15 lunch at bistro Le Repaire 100 av Daumesnil (100 meters)
14.30 Aurélien Desoeuvres, Montpellier
15.30 Mathieu Hemery, Inria Saclay
Around approximate majority processes
16.30 coffee
19.00 DInner at L'alchimiste 181 rue de Charenton (200 meters)
April 5th
9.00 Coffee
9.30 Eléonore Bellot, Inria Saclay,
On justifying chains of Michaelis-Menten reductions
10.00 François Lemaire, Lille
Slow/fast reduction in Maple using differential algebra
11.00 Alexandru Losif, Aachen
Dynamical systems with toric positive steady states
12.00 Lunch at Bistro Le Repaire
13.30 Extra talks and dIscussions
16.00 end
Abstracts of talks (20-40mn)
Andreas Weber, Univ. Bonn
Symbiont advances, deliverables and deadlines
Ovidiu Radulescu, Montpellier
Progress report on tropical geometry inspired model analysis
Aurélien Desoeuvres, Montpellier
On network robustness
Eléonore Bellot, Inria Saclay,
On justifying chains of Michaelis-Menten reductions
François Lemaire, Lille
Slow/fast reduction in Maple using differential algebra
Alexandru Losif, Aachen
Dynamical systems with toric positive steady states
Systems with toric positive steady states are generalizations of mass-action networks with binomial steady state ideal. This is of particular interest as in many applications only the positive steady states are relevant. For these systems we show that, in the space of total concentrations, multistationarity is scale invariant. Moreover, for these systems we give semialgebraic conditions for multistationarity in terms of only the total concentrations. For the sequential distributive two-site phosphorylation we show that multistationarity is possible only if the total concentration of the substrate is larger than either the concentration of the kinase or the phosphatase (Michaelis-Menten regime). In general testing for toric positive steady states is a hard problem. In this context we discuss dynamical systems with the isolation property and we show that they have toric positive steady states. This work is part of the author's PhD thesis (to be defended) and it is joint work with Carsten Conradi and Thomas Kahle.
Jakob Ruess, Inbio - Pasteur, Lifeware - Inria Saclay
Molecular noise of innate immunity shapes bacteria-phage ecologies
Mathematical models have been used successfully at diverse scales of biological organization, ranging from ecology and population dynamics to stochastic reaction events occurring between individual molecules in single cells. Generally, many biological processes unfold across multiple scales, with mutations being the best studied example of how stochasticity at the molecular scale can influence outcomes at the population scale. In many other contexts, however, an analogous link between micro- and macro-scale remains elusive, primarily due to the challenges involved in setting up and analyzing multi-scale models. We employ such a model to investigate how stochasticity propagates from individual biochemical reaction events in the bacterial innate immune system to the ecology of bacteria and bacterial viruses. We show analytically how the dynamics of bacterial populations are shaped by the activities of immunity-conferring enzymes in single cells and how the ecological consequences imply optimal bacterial defense strategies against viruses. Our results suggest that bacterial populations in the presence of viruses can either optimize their initial growth rate or their steady state population size, with the first strategy favoring simple and the second strategy favoring complex bacterial innate immunity.