Toxicity assessment of titanium dioxide nanoparticles on microorganisms through topological data analysis of high dimensional single-cell nanomechanical data.

There is a growing interest in the development of methods for the detection of nanoparticle (NP) toxicity to living organisms based on the analysis of relevant multidimensional data sets. In particular the detection of preliminary signs of NPs toxicity effects would benefit from the selection of data featuring NPs-induced alterations of biological barriers. Accordingly, we present an original Topological Data Analysis (TDA) of the nanomechanical properties of Escherichia coli cell surface, evaluated by multiparametric Atomic Force Microscopy (AFM) after exposure of the cells to increasing concentrations of titanium dioxide nanoparticles (TiONPs).

Principles, barriers and enablers to agroecological animal production systems: a qualitative approach based on five case studies.

Agroecology is among the most promising options to alleviate the negative impacts of animal farming on the environment and build local food systems based on ethically acceptable production methods. So far, most of the research on agroecological animal production systems was conducted at farm scale, and the potential of agroecological principles addressing social dimensions and food system-level approaches has been underexplored. Here, we analyse how the whole set of agroecological principles was mobilised in five case studies on grassland-based, silvopastoral or integrated crop-livestock systems in Switzerland, Guadeloupe, French uplands, Bulgaria and Andalucía.

Electrostatic interactions between soft nanoparticles beyond the Derjaguin approximation: Effects of finite size of ions and charges, dielectric decrement and ion correlations.

Hypothesis: Electrostatic interactions between colloids are governed by the overlap of their electric double layers (EDLs) and the ionic screening of the structural charges distributed at their core surface and/or in their peripheral ion-permeable shell, relevant to soft particles like polymer colloids and microorganisms. Whereas ion size-mediated effects on the organization of isolated EDLs have been analysed, their contribution to the electrostatic energy of interacting soft particles has received less attention THEORY AND SIMULATIONS: Herein, we elaborate a formalism to evaluate the electrostatic interaction energy profile between spherical core/shell particles, building upon a recent Poisson-Boltzmann theory corrected for the sizes of ions and particle structural charges, for ion correlations and dielectric decrement. Interaction energy is derived from pairwise disjoining pressure and exact Surface Element Integration method, beyond the Derjaguin approximation.

Biophysical insights into sugar-dependent medium acidification promoting YfaL protein-mediated self-aggregation, biofilm formation and acid stress resistance.

The ability of bacteria to interact with their environment is crucial to form aggregates and biofilms, and develop a collective stress resistance behavior. Despite its environmental and medical importance, bacterial aggregation is poorly understood and mediated by few known adhesion structures. Here, we identified a new role for a surface-exposed protein, YfaL, which can self-recognize and induce bacterial autoaggregation.