The Arabidopsis Target of Rapamycin kinase regulates ammonium assimilation and glutamine metabolism.

In eukaryotes, a target of rapamycin (TOR) is a well-conserved kinase that controls cell metabolism and growth in response to nutrients and environmental factors. Nitrogen (N) is an essential element for plants, and TOR functions as a crucial N and amino acid sensor in animals and yeast. However, knowledge of the connections between TOR and the overall N metabolism and assimilation in plants is still limited.

High-throughput site-directed mutagenesis using oligonucleotides synthesized on DNA chips.

Site-directed mutagenesis has greatly helped researchers both to understand the precise role of specific residues in coding sequences and to generate variants of proteins that have acquired new characteristics. Today's demands for more complete functional cartographies of proteins and advances in selection and screening technologies require that site-directed mutagenesis be adapted for high-throughput applications. We describe here the first generation of a library of single and multiple site-directed mutants using a mixture of oligonucleotides synthesized on DNA chips.

Droplet evaporation study applied to DNA chip manufacturing.

DNA chips are potentially powerful technologies for genotyping and gene expression profiling that rely on comparative analyses of up to thousands of "spots of analysis" on a glass support. The spot quality throughout the support influences spot-to-spot variations within an array and the repeatability of data across experiments. For glass slide DNA microarrays, droplets of DNA solution are deposited on functionalized glass slides and left to react through complete evaporation of the droplet.

New method for DNA microarrays development: applied to human platelet antigens polymorphisms.

DNA microarrays are a powerful experimental tool for the detection of specific genomic sequences and are invaluable to a broad array of applications: clinical diagnosis, personalized medicine, drug research and development, gene therapy, food control technologies, and environmental sciences. Alloimmunization to human platelet antigens (HPAs) is commonly responsible for neonatal alloimmune thrombocytopenia, post-transfusional purpura and platelet transfusion refractoriness. Using DNA microarrays, we developed a diagnosis to type the biallelic HPA-1 platelet group.

Implementation of DNA chips obtained by microprojection for diagnostic and personalized medicine.

It is expected that rapidly emergent new fields of application for DNA chips will be Diagnostic and Personalized Medicine. These new applications will require a limited number of probes, generally from 100 to 1000. So, after a brief review of the existing techniques to manufacture DNA chips, which are efficient for R&D applications and which often require a higher number of probes, we shall first report some advances in the silanization of the substrates and the grafting of probes to improve the robustness and the reliability of the devices.