Evaluation of two protein extraction protocols for Pichia anomala proteome analysis.

Pichia anomala (strain Kh6) was isolated from the surface of apple fruits and selected for its high and reliable biocontrol activity against Botrytis cinerea and Penicillium expansum. Its main modes of action have until now been studied using essentially microbiological and molecular approaches. The study continues now using the proteomic approach and considering the in situ P. anomala/B. cinerea/apple interaction. Two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) is one of the most powerful tools used for proteomic analysis. It combines two sequential separation steps, the first dimension via isoelectric focusing (IEF) and the second one by SDS PAGE. Although recent advances in 2-D PAGE, the extraction of the whole proteome and the removal of interfering contaminants still limit its application. Sample preparation constitutes indeed a critical influential step for IEF which in turn affects 2-D gel quality. The objective of the present work was thus to develop an effective protein extraction protocol designed for 2-D PAGE analysis of the proteome of P. anomala strain Kh6. As a starting point, two contrasting protein extraction protocols were chosen to be evaluated in terms of protein yield and one-dimensional (1-D) SDS PAGE and 2-D PAGE gel patterns. The first protocol uses a urea/thiourea-based lysis buffer whereas the second protocol utilizes a hot SDS-based lysis buffer with an additional precipitation step. The comparison model used consisted of apples treated with strain Kh6 alone (K) and apples first treated with Kh6 and then inoculated with B. cinerea conidia (KB). Growth kinetics of strain Kh6 on wounded apples was determined and found to be not affected by the presence of B. cinerea conidia. Proteins were extracted from yeast pellets collected at both the exponential and stationary phases of strain Kh6 growth on apples. The evaluation of both extraction protocols indicates that more proteins were extracted with the SDS protocol and, according to 1-D assays, higher molecular weight proteins were obtained with the ‘urea/thiourea’ protocol and, regardless of the protocol used, more bands were obtained during the exponential phase. 2-D assays are currently underway and the corresponding results will be presented

Archéologie et espaces (protohistoire, Antiquité)

Jean-Pierre Albert, directeur d’étudesPhilippe Boissinot, maître de conférencesChristine Delaplace, maître de conférences à l’Université Toulouse-II/Le Mirail Continuités et discontinuités culturelles entre anthropologie, archéologie et histoire La première séance a été consacrée à un rappel par les trois organisateurs des acquis des années précédentes, en insistant particulièrement sur le fait que l’identité n’est ni une chose, ni une propriété, mais une relation (d’équivalence). Philippe Bo..

Archéologie et espaces (protohistoire, Antiquité)

Jean-Pierre Albert, directeur d’étudesPhilippe Boissinot, maître de conférencesChristine Delaplace, maître de conférences à l’Université Toulouse-II/Le Mirail Continuités et discontinuités culturelles entre anthropologie, archéologie et histoire La première séance a été consacrée à un rappel par les trois organisateurs des acquis des années précédentes, en insistant particulièrement sur le fait que l’identité n’est ni une chose, ni une propriété, mais une relation (d’équivalence). Philippe Bo..

Liquids' atomization with two different nozzles: Modeling of the effects of some processing and formulation conditions by dimensional analysis

Liquid atomization is a largely widespread unit operation. The disintegration of a liquid into droplets depends on the nature of the nozzle, on the process parameters as well as physicochemical characteristics of the fluid. The aim of this work is to study the contribution of the process (liquid outlet speed and air pressure) and physicochemical (viscosity and surface tension) factors on the size distribution of droplets generated by single- and two-fluid flat spray nozzles. The obtained droplet median diameters which range between 77 and 594 mu m for the single-fluid nozzle and between 11 and 599 mu m for the two-fluid nozzle, are discussed in relation with operating conditions of atomization process. Dimensional analysis was performed as a modeling approach. Despite energy input for the droplet formation is known to be influenced by different origins according to single and two-fluid nozzles, it is shown that a unique correlation, with specific values of parameters for each nozzle type, gathers all the parameters affecting droplet size. In the range of process and formulation parameters tested, this correlation is validated and gives satisfactory agreement for the single- and two-fluid nozzles

TRACES – Travaux de recherches archéologiques sur les cultures, les espaces et les sociétés

Jean-Pierre Albert, directeur d’étudesPhilippe Boissinot, maître de conférencesChristine Delaplace, maître de conférences à l’UTM Continuités, ruptures, chaos : les transformations sociales au regard de l’anthropologie, l’archéologie et l’histoire Le fait d’y prouver quelque chose plutôt que rien, est dans la définition minimale d’une science. Or, l’archéologie peut parfois se targuer d’apporter des preuves que d’autres disciplines, trop dépendantes des points de vue des acteurs, ne peuvent f..

CAS – Centre d’anthropologie sociale

Jean-Pierre Albert, directeur d’étudesPhilippe Boissinot, maître de conférencesChristine Delaplace, maître de conférences à l’UTM Continuités et discontinuités culturelles entre anthropologie, archéologie et histoire Faisant suite à plusieurs séminaires traitant de la question générale des identités, cette année a été consacrée à la question plus politique des peuples qui s’ancrent dans une origine et assurent leur maintenance par le travail de quelques acteurs, en donnant plus de place cette..

CAS – Centre d’anthropologie sociale

Jean-Pierre Albert, directeur d’étudesPhilippe Boissinot, maître de conférencesChristine Delaplace, maître de conférences à l’UTM Continuités et discontinuités culturelles entre anthropologie, archéologie et histoire Faisant suite à plusieurs séminaires traitant de la question générale des identités, cette année a été consacrée à la question plus politique des peuples qui s’ancrent dans une origine et assurent leur maintenance par le travail de quelques acteurs, en donnant plus de place cette..

Des plateformes analytiques et technologiques pour le développement de nouveaux biostimulants et agents de biocontrôle (PHENIX_BIOCONTROL_ULIEGE)

The PHENIX-BIOCONTROL-ULIEGE project relies on the analytical and technological platforms of the PHENIX portfolio to develop new biostimulants and control agents, in connection with the IIS DigiBiocontrol. This project is coordinated by Pr. Philippe Jacques from Gembloux Agro-Bio Tech (University of Liège), who is also the leader of the IIS DigiBiocontrol initiative. Four Work Packages are brached to reinforce 6 key competence axes of innovation in biostimulation and biocontrol: new screening approaches, mode of action characterization, control mode activity, production processes, formulation and texturing, and greenhouse and field demonstration.Le projet PHENIX-BIOCONTROL-ULIEGE s'appuie sur les plateformes analytiques et technologiques du portefeuille PHENIX pour développer de nouveaux biostimulants et agents de contrôle, en lien avec l'IIS DigiBiocontrol. Ce projet est coordonné par le Pr. Philippe Jacques de Gembloux Agro-Bio Tech (Université de Liège), qui est également le chef de file de l'initiative IIS DigiBiocontrol. Quatre Work Packages sont mis en place pour renforcer 6 axes de compétences clés en matière d'innovation dans le domaine de la biostimulation et du biocontrôle : nouvelles approches de criblage, caractérisation du mode d'action, activité du mode de contrôle, processus de production, formulation et texturation, et validation en serre et en champ.Projet PHENIX Biocontrol ULiège-SP

Influence of whip speed ratios on the inclusion of air into a bakery foam produced with a planetary mixer device

In the present study, dimensional analysis has been developed in order to identify the ratios governing the foam development network, with mixers combining dual whip revolution speeds. It is first suggested that, for a given planetary whip mixer and foaming solution, the set of dimensionless ratios characterizing the course of gas hold-up can be reduced to modified Froude and revolution numbers, as in the case of a classical mixing system. This requires the introduction of a characteristic velocity, instead of the two individual rotational speeds of the whip, in the corresponding list of governing parameters. An analytical expression for this characteristic velocity is then proposed, and gas hold-up measurements are made at various whip speed ratios, using a given food model-recipe, containing whole eggs and sugar. Our experimental results were evaluated, in order to validate the proposed dimensional analysis. It is shown that the aeration process requires a very low, modified revolution number to reach steady state values. It is also shown that the asymptotic values of gas hold-up are influenced by the modified Froude number. Depending on the values of the modified Froude number, it is noted that coalescence can occur, which then contributes to a reduction in gas hold-up. It has also been established that the modified Froude number can account for the eccentricity of planetary mixers, and consequently, that this number is a robust indicator for the determination of the optimum gas hold-up value, when air incorporation is produced by various planetary whipping devices. The results described in this paper enable foaming processes using planetary whipping mixers to be optimized, by proposing a framework in which the impeller speed ratio and aeration time can be set in such a way as to control the simultaneous entrainment and disentrainment of gas. Finally, this work can be further extended to other gas/liquid applications in which planetary mixers are used, such as surface aeration in wastewater treatment plants

Biocontrol proteomics:Implication of the pentoses phosphates pathway in the antagonist effect of Pichia anomala against Botrytis cinerea on apple.

Pichia anomala strain K was previously identified as an efficient biocontrol agent of the apple pathogen, Botrytis cinerea. Further study demonstrated the complexicity of the mode of action of P. anomala against B. cinerea. A molecular study revealed implication of exo-β-1,3-glucanases in the mode of action of P. anomala but suggested implication of other factors. The present study aims to increase our knowledge of the mode of action of P. anomala strain Kh6 against B. cinerea using an in situ approach allowing interactions between organisms, and the proteomic tool allowing to study the ultime expression of the genome. One wound per apple were covered by a membrane and inoculated by P. anomala then by B. cinerea or not. Samples were collected at different incubation times to identify the responses of P. anomala to the presence of B. cinerea. After extraction, proteins were separated on 2-D gels. Spots influenced were identified by MALDI-ToF. In exponential phase, P. anomala Kh6 orientates its energetic metabolism from the glycolysis to the oxidative phosphorylation and sets up the pentose phosphate pathway. Thanks to this new pathway, P. anomala probably obtains energy and nucleic acids allowing to colonize the wound as fast as in absence of B. cinerea. In stationary phase, no differences in the P. anomala energetic metabolism, in absence and in presence of B. cinerea were observed. During that phase, P. anomala seems to use the alcoholic fermentation in order to face the nutrients impoverishment of the substrate