The Goldilocks principle and antibiotic resistance in bacteria.

We have designed and fabricated a microecology to mimic a naturally occurring bacterial culture, which includes the stress gradient, metapopulation, and cellular motility. In this microecology, we show that it is possible to fix the resistance to the mutagenic antibiotic Ciprofloxacin in wild-type Escherichia coli within 10 h. We found the evolution of resistance is further accelerated in microecology if bacteria have already acquired the phenotype of growth advantage at the stationary phase (GASP).

Acceleration of emergence of bacterial antibiotic resistance in connected microenvironments.

The emergence of bacterial antibiotic resistance is a growing problem, yet the variables that influence the rate of emergence of resistance are not well understood. In a microfluidic device designed to mimic naturally occurring bacterial niches, resistance of Escherichia coli to the antibiotic ciprofloxacin developed within 10 hours. Resistance emerged with as few as 100 bacteria in the initial inoculation.

Assessment of bursting activity and interspike intervals variability: a case study for methodological comparison.

The detection and characterization of bursting activity remains a topic where no consensual definition has been reached so far. We compare here three different approaches of spike trains variability: statistical characterization (average frequency, coefficient of variation), burst detection (Poisson and rank surprise) and multi-scale analysis (detrended fluctuations analysis). Using both real and simulated data, we show that Poisson surprise provides information closely related to the coefficient of variation and that rank surprise detects significant bursts which are associated with long-range correlations.

Detection of biological macromolecules on a biochip dedicated to UV specific absorption.

This work describes an ultraviolet biosensing technique based on specific molecular absorption detected with a previously developed spectrally selective aluminum gallium nitride (AlGaN) based detector. Light absorption signal of DNA and proteins, respectively at 260 nm and 280 nm, is used to image biochips. To allow detection of protein or DNA monolayers at the surface of a biochip, we develop contrast-enhancing multilayer substrates.