Papers by veronique anton
Exposure to high static or pulsed magnetic fields does not affect cellular processes in the yeast Saccharomyces cerevisiae
HAL (Le Centre pour la Communication Scientifique Directe), 2010
We report results of a study of the effects of strong static (up to 16 T for 8 h) and pulsed (up ... more We report results of a study of the effects of strong static (up to 16 T for 8 h) and pulsed (up to 55 T single-shot and 4 x 20 T repeated shots) magnetic fields on Saccharomyces cerevisiae cultures in the exponential phase of growth. In contrast to previous reports restricted to only a limited number of cellular parameters, we have examined a wide variety of cellular processes: genome-scale gene expression, proteome profile, cell viability, morphology, and growth, metabolic and fermentation activity after magnetic field exposure. None of these cellular activities were impaired in response to static or pulsed magnetic field exposure. Our results confirm and extend previous reports on the absence of magnetic field effects on yeast and support the hypothesis that magnetic fields have no impact on the transcriptional machinery and on the integrity of unicellular biological systems.
Nanobiotechnologies : les nanobiotechnologies au service des biopuces, l'exemple toulousain
Les progres recents des nanotechnologies permettent d entrevoir une miniaturisation des dispositi... more Les progres recents des nanotechnologies permettent d entrevoir une miniaturisation des dispositifs jusqu a l echelle moleculaire. L utilisation des nanotechnologies dans des biopuces ou labopuces permettra de reduire considerablement les volumes de solutions biologiques au dessous du femto-litre, de detecter des interactions specifiques entre biomolecules avec une sensibilite proche de la molecule unique ou bien de positionner des biomolecules actives sur des supports avec une precision la encore proche de la molecule unique. Illustration avec la plate-forme genomique de Toulouse et le Laboratoire d Architecture et d Analyses des Systemes a travers deux exemples : le depot de biomolecules par lithographie douce et la biodetection ultrasensible a l aide de nanoelectrodes.
SummaryChromosome and plasmid segregation in bacteria are mostly driven by ParABS systems. These ... more SummaryChromosome and plasmid segregation in bacteria are mostly driven by ParABS systems. These DNA partitioning machineries rely on large nucleoprotein complexes assembled on centromere sites (parS). However, the mechanism of how a fewparS-bound ParB proteins nucleate the formation of highly concentrated ParB clusters remains unclear despite several proposed physico-mathematical models. We discriminated between these different models by varying some key parametersin vivousing the plasmid F partition system. We found that ‘Nucleation & caging’ is the only coherent model recapitulatingin vivodata. We also showed that the stochastic self-assembly of partition complexes (i) does not directly involve ParA, (ii) results in a dynamic structure of discrete size independent of ParB concentration, and (iii) is not perturbed by active transcription but is by protein complexes. We refined the ‘Nucleation & Caging’ model and successfully applied it to the chromosomally-encoded Par system ofVib...
Biotechnology. Theory and practice., 2013
Subinhibitory concentrations (sub -MICs) of antibiotics do not kill bacteria, but they are able t... more Subinhibitory concentrations (sub -MICs) of antibiotics do not kill bacteria, but they are able to interfere with important aspects of bacterial cell function, such as adhesion to host cells, surface bacterial energy, susceptibility to host defense mechanisms, inhibition of enzyme function and toxin production. In order to understand how H. pylori copes with environmental stress and what facilitates the emergence of RIF mutants in H. pylori, we used DNA microarrays to compare the gene expression profiles of H. pylori in the presence and absence of subinhibitory concentrations of rifampicin (1/16 MIC (0.1 mg/L), 1/8 MIC (0,2mg/L), ¼ MIC (0,4 mg/L), and ½ MIC (0,8 mg/L). We found that еhe expression of 57 genes (of the 1,576 genes analyzed) was increased more than ≥ 1,5 -fold, and the expression of only 29 genes was decreased more than ≤ 1,5 -fold in significant way (p-value < 0,05), when H. pylori was treated with sub -MICs of RIF. No correlation was found between the sub -MICs of RIF and gene expression. We conclude that the alteration in the transcriptional pattern of H. pylori after the exposure to sub -MICs of RIF is mainly due to a direct interaction between rifampicin and the RNA polymerase β-subunit. Finally, we propose that subinhibitory concentrations of rifampicin may lead to an increase in the number of hypermutable cells in the H. pylori population.
Silicon-based microcantilevers for multiple biological sample deposition
TRANSDUCERS '03. 12th International Conference on Solid-State Sensors, Actuators and Microsystems. Digest of Technical Papers (Cat. No.03TH8664)
Arrays of silicon-based microcantilevers with passivated aluminum electrodes properly designed ha... more Arrays of silicon-based microcantilevers with passivated aluminum electrodes properly designed have been used to generate microarrays by depositing microspots of biological samples using a direct contact deposition technique. Using this approach, with a single loading, arrays of more than a hundred spots, from the femtoliter to the picoliter range, containing fluorescent-labelled oligonucleotides (15 mers) and proteins were directly patterned on
Journal of microbiological methods, 2015
Detection of harmful algal blooms has become a challenging concern because of the direct impacts ... more Detection of harmful algal blooms has become a challenging concern because of the direct impacts on public health and economy. The identification of toxic dinoflagellates and diatoms in monitoring programs requires an extensive taxonomic expertise and is time consuming. Advances in molecular biology have allowed the development of new approaches, more rapid, accurate and cost-effective for detecting these microorganisms. In this context, we developed a new DNA microarray (called, Phytochip) for the simultaneous detection of multiple HAB species with a particular emphasis on Pseudo-nitzschia species. Oligonucleotide probes were designed along the rRNA operon. After DNA extraction, the target rDNA genes were amplified and labeled using an asymmetric PCR; then, the amplicons were hybridized to the oligonucleotide probes present on the chips. The total assay from seawater sampling to data acquisition can be performed within a working day. Specificity and sensitivity were assessed by usi...
In vitro engineered muscle: Identification and characterization of murine dermal precursor cells with myogenic potential
Neuromuscular Disorders, 2014
Our group has recently derived skeletal muscle from dermis-derived cells, by using an extracellul... more Our group has recently derived skeletal muscle from dermis-derived cells, by using an extracellular matrix that recreates the myogenic niche. After one week of differentiation, we observed isolated, twitching myotubes followed by spontaneous contractions of the entire tissue-engineered muscle construct. In vitro engineered myofibers expressed canonical markers, ultrastructure and electrophysiological characteristics of skeletal muscle. Interestingly, after one-month engineered muscle constructs showed progressive degradation of the myofibers concomitant with fatty infiltration, paralleling the natural course of muscular degeneration. However, we do not yet know how dermis-resident precursors are related with our isolated-myogenic precursors, a critical point for extrapolating our results to the human system. Knowing that dermal cells and muscle cells share a common embryonic origin from somite-derived dermomyotome and taking into account that there are different types of cells within the skin that have myogenic potential, our main objective is to identify and characterize the origin of murine dermal subpopulation with a myogenic potential, hypothesizing that may be (i) satellite cells from the Panniculus carnosus, (ii) dermomyotome-derived adult stem cells, (iii) perivascular cells and/or (iv) neural crest-derived precursor cells. For this end, lineage tracing experiments [(i) Pax3-GFP, (ii) Pax7CE, (iii) Myf5-Cre, (iv) CSPG4-Cre, and (v) Sox10-Cre] combined with FACS strategies and cellular differentiation assays have been developed. Our results show a high contribution of Myf5+ cells, a low contribution of Cspg4+ cells, and no contribution of Sox10+ cells to dermis-derived myogenic precursor cell subset. In principle, that means that dermomyotome-derived but not neural crest-derived cells are involved in subsequent engineered muscle differentiation.
PLoS ONE, 2011
We previously developed a fermentation protocol for lipid accumulation in the oleaginous yeast Y.... more We previously developed a fermentation protocol for lipid accumulation in the oleaginous yeast Y. lipolytica. This process was used to perform transcriptomic time-course analyses to explore gene expression in Y. lipolytica during the transition from biomass production to lipid accumulation. In this experiment, a biomass concentration of 54.6 g CDW /l, with 0.18 g/ g CDW lipid was obtained in ca. 32 h, with low citric acid production. A transcriptomic profiling was performed on 11 samples throughout the fermentation. Through statistical analyses, 569 genes were highlighted as differentially expressed at one point during the time course of the experiment. These genes were classified into 9 clusters, according to their expression profiles. The combination of macroscopic and transcriptomic profiles highlighted 4 major steps in the culture: (i) a growth phase, (ii) a transition phase, (iii) an early lipid accumulation phase, characterized by an increase in nitrogen metabolism, together with strong repression of protein production and activity; (iv) a late lipid accumulation phase, characterized by the rerouting of carbon fluxes within cells. This study explores the potential of Y. lipolytica as an alternative oil producer, by identifying, at the transcriptomic level, the genes potentially involved in the metabolism of oleaginous species.
OMICS: A Journal of Integrative Biology, 2007
LEC rats have a mutation in a gene related to hepatic copper excretion, the Atp7b gene. As a cons...
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Papers by veronique anton