The Date Palm (Phoenix dactylifera L.) leaf proteome: identification of a gender biomarker to screen male parents

Abstract To establish a proteomic reference map of date palm leaves (Deglet Nour cultivar), we separated and identified leaf proteins using two-dimensional polyacrylamide gel electrophoresis and mass spectrometry, respectively. In total, 284 spots were excised from gel and analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). Among them, 158 were successfully identified (i.e, a success rate of 55.6%) conducting to the identification of 126 unique proteins. These proteins were then clustered according to their functional annotations. Identified proteins were involved in metabolism, electron transport, photosynthesis, protein synthesis, cell structure or defence. However, 29.4 % of the identifications gave unknown function. We then compared the proteome map of female and male trees. Only one discriminated spot was found to be specific of the gender. We identified the corresponding protein as an ABC superfamily ATP binding cassette transporter, ABC protein, a protein whose an ortholog in Arabidopsis thaliana was already reported as required for male fertility and pollen formation. The relevance of this protein as gender biomarker was then confirmed in four other cultivars, i.e., Aligue, Khouet Aligue, Kentichi and Kenta. Such biomarker should be helpful in rapidly distinguishing date palm gender of immature trees

Identification of Biofilm-Associated Cluster (bac) in Pseudomonas aeruginosa Involved in Biofilm Formation and Virulence

Biofilms are prevalent in diseases caused by Pseudomonas aeruginosa, an opportunistic and nosocomial pathogen. By a proteomic approach, we previously identified a hypothetical protein of P. aeruginosa (coded by the gene pA3731) that was accumulated by biofilm cells. We report here that a ΔpA3731 mutant is highly biofilm-defective as compared with the wild-type strain. Using a mouse model of lung infection, we show that the mutation also induces a defect in bacterial growth during the acute phase of infection and an attenuation of the virulence. The pA3731 gene is found to control positively the ability to swarm and to produce extracellular rhamnolipids, and belongs to a cluster of 4 genes (pA3729–pA3732) not previously described in P. aeruginosa. Though the protein PA3731 has a predicted secondary structure similar to that of the Phage Shock Protein, some obvious differences are observed compared to already described psp systems, e.g., this unknown cluster is monocistronic and no homology is found between the other proteins constituting this locus and psp proteins. As E. coli PspA, the amount of the protein PA3731 is enlarged by an osmotic shock, however, not affected by a heat shock. We consequently named this locus bac for biofilm-associated cluster

Caractérisation phénotypique et fonctionnelle de la protéine PA3731 de Pseudomonas aeruginosa

Dans le cadre d une recherche de nouvelles cibles contre les biofilms à P. aeruginosa, nous avons identifié une protéine impliquée dans l adhésion bactérienne. Nous avons alors caractérisé le phénotype du mutant pA3731 correspondant. Ce mutant est profondément altéré dans : sa capacité à adhérer, son swarming, sa production de rhamnolipides, sa virulence et sa résistance à la tobramycine. Une analyse du génome a montré que ce gène appartient à un cluster (pA3729-pA3732) codant pour des protéines hypothétiques. Par sa structure secondaire la protéine PA3731 est proche de PspA d E. coli. Néanmoins, des différences avec le cluster psp nous ont conduits à baptiser le cluster bac pour Biofilm Associated Cluster. Pour déterminer la fonction du système bac, nous avons analysé l incidence d un inhibiteur de systèmes d efflux, les sécrétomes et réalisé des études des complexomes. Ces travaux préliminaires n ont pas encore apporté d éléments probants au niveau de la fonction du système bac.Biofilms are prevalent in diseases caused by P. aeruginosa. We previously identified a hypothetical protein of this bacterium that was accumulated by biofilm cells. We showed here that a pA3731 mutant is profoundly impaired in its ability to adhere, in swarming, in the rhamnolipides production, in virulence and in resistance to tobramycin. The protein PA3731 has a predicted secondary structure similar to that of the PspA of E. coli and belonged to a cluster of 4 genes (pA3729-pA3732) not previously described. However, some differences led us to named this locus bac for biofilm-associated cluster. In the aim to provide preliminary hypotheses to bac function, we compared the effect of an inhibitor of efflux systems, on the wild-type and mutant strains. We also initiated analyses of the strain secretomes and performed complexome studies by electrophoresis blue-native. These preliminary investigations have yet to provide evidence in the function of the bac system.ROUEN-BU Sciences (764512102) / SudocSudocFranceF

Proteomics dedicated to biofilmology: What have we learned from a decade of research?

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Identification par des approches protéomiques innovantes de biomarqueurs sériques prédictifs de la réponse à l'association méthotrexate/etanercept dans la polyarthrite rhumatoïde

ROUEN-BU Sciences (764512102) / SudocSudocFranceF

Predictors of treatment response in rheumatoid arthritis

International audienceThe expanding array of drugs available for treating rheumatoid arthritis is creating challenges in drug selection for the individual patient. The identification of biomarkers that predict the treatment response prior to drug exposure is therefore a current priority. This new approach, known as theranostics, is a component of personalized medicine, which involves selecting the management strategies that are most effective for a given patient at a given point in time. Antibodies to citrullinated peptides, rheumatoid factor, and the interferon signature are the most robust and best validated biomarkers identified to date. Matrices containing clinical or laboratory parameters of diagnostic or prognostic relevance may help to select the best treatment for the individual patient. Furthermore, the development of large-scale approaches requiring no a priori knowledge, such as functional genomics and metabolomics, hold considerable promise, despite persistent difficulties in replicating findings. The complexity of the treatment response in a given patient and substantial variability across patients suggest that biomarkers may be more helpful in combination than singly. The objectives of this review article are to discuss the approaches used to identify theranostic biomarkers and to present an overview of currently available biomarkers and of their performance in everyday clinical practice. However, the range of biomarkers suitable for use in daily practice remains extremely narrow

Mise en évidence de l’expression par

Legionella pneumophila est responsable de la maladie du légionnaire. On la trouve dans les eaux naturelles où elle est capable de se multiplier au sein de protozoaires. Le séquençage du génome des trois souches de L. pneumophila : Paris (souche endémique en France), Lens (responsable des récentes épidémies dans le nord de la France) et Philadelphia (responsable de la première épidémie de légionellose) ont montré que cette bactérie possède un nombre très important de gènes codant des protéines homologues aux protéines eucaryotes. En utilisant des outils bioinformatiques, nous avons mis en évidence chez cette bactérie la présence de trois gènes (tspO, omp32 et lcy) codant des polypeptides homologues à des protéines impliquées dans la formation d’un système protéique proche d’un pore de transition mitochondrial (MPTP). Dans la présente étude, nous analysons l’expression de deux de ces gènes, omp32 et lcy, par une approche protéomique

LasB and CbpD Virulence Factors of Pseudomonas aeruginosa Carry Multiple Post-Translational Modifications on Their Lysine Residues

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Phosphate deprivation is associated with high resistance to latamoxef of gel-entrapped, sessile-like Escherichia coli cells

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