Biomedical subjects

Delphine Vincent

Publications and source records attributed to Delphine Vincent.

5 recordsLinked to original sources

PubMed2006

Water and salinity stress in grapevines: early and late changes in transcript and metabolite profiles.

Grapes are grown in semiarid environments, where drought and salinity are common problems. Microarray transcript profiling, quantitative reverse transcription-PCR, and metabolite profiling were used to define genes and metabolic pathways in Vitis vinifera cv. Cabernet Sauvignon with shared and divergent responses to a gradually applied and long-term (16 days) water-deficit stress and equivalent salinity stress. In this first-of-a-kind study, distinct differences between water deficit and salinity were revealed. Water deficit caused more rapid and greater inhibition of shoot growth than did salinity at equivalent stem water potentials. One of the earliest responses to water deficit was an increase in the transcript abundance of RuBisCo activase (day 4), but this increase occurred much later in salt-stressed plants (day 12). As water deficit progressed, a greater number of affected transcripts were involved in metabolism, transport, and the biogenesis of cellular components than did salinity. Salinity affected a higher percentage of transcripts involved in transcription, protein synthesis, and protein fate than did water deficit. Metabolite profiling revealed that there were higher concentrations of glucose, malate, and proline in water-deficit-treated plants as compared to salinized plants. The metabolite differences were linked to differences in transcript abundance of many genes involved in energy metabolism and nitrogen assimilation, particularly photosynthesis, gluconeogenesis, and photorespiration. Water-deficit-treated plants appear to have a higher demand than salinized plants to adjust osmotically, detoxify free radicals (reactive oxygen species), and cope with photoinhibition.

Dehydration↗

PubMed2006

Optimization of protein extraction and solubilization for mature grape berry clusters.

Protein extraction from grape berries has been challenging, particularly in mature berries, which can have sugar concentrations as high as 26%. Grape skins and seeds contain large amounts of polyphenols, which can also interfere with efficient protein extraction. In plants, two extraction protocols, TCA/acetone-based and phenol-based methods, have been mainly used to extract proteins from different organs or tissues on many species. However, few results have been reported for grape berry clusters. We wanted to determine which of these protocols was optimal for berry clusters in order to achieve both efficient protein extraction and high spot resolution on 2-D gels. Four protocols, derived from either TCA/acetone or phenol procedures, were tested on mature Cabernet Sauvignon whole berry clusters. The phenol-based protocols were superior to the TCA/acetone methods, showing larger protein yields and greater spot resolution on 2-D gels. One method was clearly superior to the rest, a phenol-based extraction method combined with resuspension in the presence of both urea and thiourea as chaotropes. A total of 81 spots were excised and identified following MALDI-TOF/TOF MS analyses. Their identification helped further characterize the specificity of each extraction procedure.

Acetone↗

PubMed2005

Water deficits affect caffeate O-methyltransferase, lignification, and related enzymes in maize leaves. A proteomic investigation.

Drought is a major abiotic stress affecting all levels of plant organization and, in particular, leaf elongation. Several experiments were designed to study the effect of water deficits on maize (Zea mays) leaves at the protein level by taking into account the reduction of leaf elongation. Proteomic analyses of growing maize leaves allowed us to show that two isoforms of caffeic acid/5-hydroxyferulic 3-O-methyltransferase (COMT) accumulated mostly at 10 to 20 cm from the leaf point of insertion and that drought resulted in a shift of this region of maximal accumulation toward basal regions. We showed that this shift was due to the combined effect of reductions in growth and in total amounts of COMT. Several other enzymes involved in lignin and/or flavonoid synthesis (caffeoyl-CoA 3-O-methyltransferase, phenylalanine ammonia lyase, methylenetetrahydrofolate reductase, and several isoforms of S-adenosyl-l-methionine synthase and methionine synthase) were highly correlated with COMT, reinforcing the hypothesis that the zone of maximal accumulation corresponds to a zone of lignification. According to the accumulation profiles of the enzymes, lignification increases in leaves of control plants when their growth decreases before reaching their final size. Lignin levels analyzed by thioacidolysis confirmed that lignin is synthesized in the region where we observed the maximal accumulation of these enzymes. Consistent with the levels of these enzymes, we found that the lignin level was lower in leaves of plants subjected to water deficit than in those of well-watered plants.

Gene Expression Regulation, Enzymologic↗

PubMed2005

PROTICdb: a web-based application to store, track, query, and compare plant proteome data.

PROTICdb is a web-based application, mainly designed to store and analyze plant proteome data obtained by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and mass spectrometry (MS). The purposes of PROTICdb are (i) to store, track, and query information related to proteomic experiments, i.e., from tissue sampling to protein identification and quantitative measurements, and (ii) to integrate information from the user's own expertise and other sources into a knowledge base, used to support data interpretation (e.g., for the determination of allelic variants or products of post-translational modifications). Data insertion into the relational database of PROTICdb is achieved either by uploading outputs of image analysis and MS identification software, or by filling web forms. 2-D PAGE annotated maps can be displayed, queried, and compared through a graphical interface. Links to external databases are also available. Quantitative data can be easily exported in a tabulated format for statistical analyses. PROTICdb is based on the Oracle or the PostgreSQL Database Management System and is freely available upon request at the following URL: http://moulon.inra.fr/ bioinfo/PROTICdb.

Computer Graphics↗

PubMed2004

Deciphering genetic variations of proteome responses to water deficit in maize leaves.

The proteome of the basal part of growing Zea mays leaves was analyzed from 4 to 14 d after stopping watering and in well watered controls. The relative quantity of 46 proteins was found to increase in leaves of plants submitted to water deficit. Different types of responses were observed, some proteins showing a constant increase during water deficit, while others showed stabilization after a first increase or a transient increase. Isoforms encoded by the same gene showed different responses. The response to water deficit showed genetic variation. Some increased proteins were induced specifically in one of the two studied genotypes (e.g. ASR1) while others were significantly induced in both genotypes but to a different level or with different kinetics. Analyses of relations between protein quantities, relative water content (RWC) and abscisic acid (ABA) concentration allowed us to show that the quantitative variation of some proteins (e.g. ABA45 and OSR40 proteins) was linked to differences in ABA accumulation between the genotypes. Other proteins showed genetic variations that were not related to differences in water status or ABA concentration (e.g. a cystatin). Data obtained from these experiments, together with data from other experiments, contribute to the characterization of maize proteome response to drought in different conditions and in different genotypes. This characterization allows the search for candidate proteins, i.e. for protein whose genetic variation of expression could be partly responsible for the variability of plant responses to drought.

Dehydration↗