Cédric Astier

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The photosynthetic apparatus of Synechocystis sp. PCC 6714 cells grown chemoheterotrophically (dark with glucose as a carbon source) and photoautotrophically (light in a mineral medium) were compared. Dark-grown cells show a decrease in phycocyanin content and an even greater decrease in chlorophyll content with respect to light-grown cells. Analysis of(More)
Mutations conferring herbicide resistance in 3 mutant strains of the cyanobacterium Synechocystis 6714 have been characterized by gene cloning and sequencing. The mutants display very different phenotypes: DCMU-IIA is DCMU-resistant and atrazine-resistant, DCMU-IIB is DCMU-resistant and atrazine-sensitive, and Az-V is DCMU-sensitive, atrazine-resistant and(More)
Carotenoid biosynthesis in the photosynthetic bacterium Rubrivivax gelatinosus leads to the formation of hydroxyspheroidene and spirilloxanthin as the products of a branched pathway. In this study we investigated the role of the desaturase encoded by crtD which catalyses the introduction of C-3,4 double bonds into acyclic carotenoids. The desaturase was(More)
Gene transfer systems were developed inRubrivivax (Rx.) gelatinosus S1. First, a system for conjugative transfer of mobilizable plasmids fromEscherichia coli toRx. gelatinosus S1 was established. Secondly, optimal conditions for the transformation ofRx. gelatinosus S1 by electroporation were determined. A Δpuf strain was constructed. Complementation with(More)
Fish alpha-actinin purified from sea-trout and bass white muscle by means of two different extraction procedures was used to investigate the eventual presence of different muscle isoforms in Z-disks. These fish alpha-actinins have the same apparent molecular weight (100 kDa) and the same isoelectric point (pI = 5.6), and also have a total antigenic identity(More)
AIM The ubiquitin-proteasome system is known to be involved in many situations leading to skeletal muscle atrophy. However, the cellular mechanisms triggering the atrophic process initiation are still poorly understood. For short periods of rat hindlimb unloading, we assessed the specific ubiquitin targeting of sarcoplasmic or myofibrillar proteins in slow(More)
Systematic studies of the parameters influencing transformation efficiencies in Synechococcus R2 and its spontaneous pUH24 plasmid-minus variant S60, have led to substantial increases in these frequencies (up to 70 times for R2 and 9 times for S60) compared to those obtained by using previously published procedures. Important factors are the physiological(More)
The cyanobacteria Synechocystis 6803 and 6714 contain three genes (psbA) coding for the D1 protein. This protein is an essential subunit of photosystem II (PSII) and is the target for herbicides. We have used herbicide-resistant mutants to study the role of the two homologous copies of the psbA genes in both strains (the third copy is not expressed).(More)
The mechanism of excitation energy distribution between the two photosystems (state transitions) is studied in Synechocystis 6714 wild type and in wild type and a mutant lacking phycocyanin of Synechocystis 6803. (i) Measurements of fluorescence transients and spectra demonstrate that state transitions in these cyanobacteria are controlled by changes in the(More)
In rat (König et al. [1998] 28th Annual Meeting of the Society of Neuroscience, Los Angeles. 24:314.6) and mouse (Métin et al. [2000] J. Neurosci. 20:696-708), neurons migrating tangentially in the intermediate zone (IZ) of the neocortical anlage express functional AMPA receptors permeable to calcium. The role of these receptors is as yet unknown. We(More)