References of "Lecler, Renaud"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailFunction of the chloroplastic NADP(H) dehydrogenase NDA2 for the H2 photoproduction in sulphur-deprived Chlamydomonas reinhardtii
Mignolet, Emmanuel ULg; Lecler, Renaud ULg; Ghysels, Bart ULg et al

in Journal of Biotechnology (2012), 162

The relative contributions of the PSII-dependent and Nda2-dependent pathways for H2 photoproduction were investigated in the green microalga Chlamydomonas reinhardtii after suphur-deprivation. For this ... [more ▼]

The relative contributions of the PSII-dependent and Nda2-dependent pathways for H2 photoproduction were investigated in the green microalga Chlamydomonas reinhardtii after suphur-deprivation. For this purpose, H2 gas production was compared for wild-type and Nda2-deficient cells with or without DCMU (a PSII-inhibitor) in the same experimental conditions. Nda2-deficiency caused a 30 % decrease of the maximal H2 photoevolution rate observed shortly after the establishment of anoxia, and an acceleration of the decline of H2 photoevolution rate with time. DCMU addition to Nda2-deficient cells completely inhibited H2 photoproduction, showing that the PSII-independent H2 photoproduction relies on the presence of Nda2, which feeds the photosynthetic electron transport chain with electrons derived from oxidative catabolism. Nda2-protein abundance increased as a result of sulphur deprivation and further during the H2 photoproduction process, resulting in high rates of non-photochemical plastoquinone reduction in control cells. Nda2-deficiency had no significant effect on photosynthetic and respiratory capacities in sulphur-deprived cells, but caused changes in the cell energetic status (ATP and NADPH/NADP+ ratio). The rapid decline of H2 photoevolution rate with time in Nda2-deficient cells revealed a more pronounced inhibition of H2 photoproduction by accumulated H2 in the absence of non-photochemical plastoquinone reduction. Nda2 is therefore important for linking H2 photoproduction with catabolism of storage carbon compounds, and seems also involved in regulating the redox poise of the photosynthetic electron transport chain during H2 photoproduction. [less ▲]

Detailed reference viewed: 46 (12 ULg)
Full Text
Peer Reviewed
See detailInterplay between non-photochemical plastoquinone reduction and re-oxidation in pre-illuminated Chlamydomonas reinhardtii: a chlorophyll fluorescence study
Houyoux, Pierre-Alain; Ghysels, Bart ULg; Lecler, Renaud ULg et al

in Photosynthesis Research (2011), 110

In photosynthetic eukaryotes, the redox state of the plastoquinone (PQ) pool is an important sensor for mechanisms that regulate the photosynthetic electron transport. In higher plants, a multimeric ... [more ▼]

In photosynthetic eukaryotes, the redox state of the plastoquinone (PQ) pool is an important sensor for mechanisms that regulate the photosynthetic electron transport. In higher plants, a multimeric nicotinamide adenine dinucleotide (phosphate) (NAD(P))H dehydroge- nase (NDH) complex and a plastid terminal oxidase (PTOX) are involved in PQ redox homeostasis in the dark. We recently demonstrated that in the microalgae Chla- mydomonas reinhardtii, which lacks the multimeric NDH complex of higher plants, non-photochemical PQ reduction is mediated by a monomeric type-II NDH (Nda2). In this study, we further explore the nature and the importance of non-photochemical PQ reduction and oxidation in relation to redox homeostasis in this alga by recording the ‘dark’ chlorophyll fluorescence transients of pre-illuminated algal samples. From the observation that this fluorescence tran- sient is modified by addition of propyl gallate, a known inhibitor of PTOX, and in a Nda2-deficient strain we conclude that it reflects post-illumination changes in the redox state of PQ resulting from simultaneous PTOX and Nda2 activity. We show that the post-illumination fluo- rescence transient can be used to monitor changes in the relative rates of the non-photochemical PQ reduction and reoxidation in response to different physiological situa- tions. We study this fluorescence transient in algae acclimated to high light and in a mutant deficient in mitochondrial respiration. Some of our observations indi- cate that the chlororespiratory pathway participates in redox homeostasis in C. reinhardtii. [less ▲]

Detailed reference viewed: 30 (15 ULg)
Full Text
See detailLa (photo)production d'hydrogène par les microorganismes
Lecler, Renaud ULg

Conference (2011, April 04)

Detailed reference viewed: 61 (15 ULg)
Full Text
Peer Reviewed
See detailFunctional analysis of hydrogen photoproduction in respiratory-deficient mutants of Chlamydomonas reinhardtii
Lecler, Renaud ULg; Godaux, Damien ULg; Vigeolas, Hélène ULg et al

in International Journal of Hydrogen Energy (2011), 36

In this paper, mitochondrial mutants of Chlamydomonas reinhardtii defective for respiratory complex I (NADH:ubiquinone oxidoreductase), complex III (ubiquinol cytochrome c oxidoreductase) and both ... [more ▼]

In this paper, mitochondrial mutants of Chlamydomonas reinhardtii defective for respiratory complex I (NADH:ubiquinone oxidoreductase), complex III (ubiquinol cytochrome c oxidoreductase) and both complexes I and III were analyzed for H2 photoproduction. Several parameters were followed during the S-deficiency stage and the anaerobic stage leading to H2 photoproduction. At the early aerobic S-deficiency stage, starch and neutral lipids accumulated in all strains but their amount was significantly decreased in mutants compared to wild type. During the H2 photoproduction process, whereas starch content strongly decreased in all strains, neutral lipid amount remained nearly unchanged, suggesting that starch degraded by glycolysis is the preferential substrate for energy production during anaerobiosis. The mutants displayed a decrease in H2 photoproduction correlating to the number of active mitochondrial proton-pumping sites lost in the strains. Our results thus highlight the critical role of oxidative phosphorylation during the first (aerobic) stage of S-starvation when carbon resources are accumulated. [less ▲]

Detailed reference viewed: 91 (55 ULg)
Full Text
See detail(Functionnal) analysis of hydrogen production in Chlamydomonas reinhardtii mitochondrial mutants
Lecler, Renaud ULg; Godaux, Damien ULg; Hamilton, Christopher ULg et al

Poster (2010, June 27)

Mitochondrial Chlamydomonas mutants for respiratory complexes present a decreased dark respiration and apparent yield of photosynthetic linear electron flow. They accumulate reducing power such as NAD(P)H ... [more ▼]

Mitochondrial Chlamydomonas mutants for respiratory complexes present a decreased dark respiration and apparent yield of photosynthetic linear electron flow. They accumulate reducing power such as NAD(P)H and show lower levels of ATP. Under restrictive conditions, like sulfur depletion and anoxia, Chlamydomonas is able to produce hydrogen towards the activation of a chloroplatic O2-sensitive Fe-hydrogenase which catalyses the reduction of electrons to H2. In this study we used an adapted Melis protocol to analyse hydrogen evolution of mitochondrial mutants. For this aim a simple-flask system was built with gaz collecting tubes. A parallel flask was used for GC analyses. [less ▲]

Detailed reference viewed: 45 (13 ULg)
Full Text
See detailNADH pathway and H2 production in Chlamydomonas reinhardtii
Lecler, Renaud ULg

Scientific conference (2009, December 12)

Detailed reference viewed: 10 (5 ULg)