Selection for Improved Saccharification Efficiency in Alfalfa Stems Assessed by Enzyme-Released Glucose

Alfalfa (Medicago sativa L.) has a high potential for sustainable bioethanol production, particularly because of its low reliance on N fertilizer (Samac et al. 2006). Genetic improvement for the accumulation of readily fermentable non-structural carbohydrates (NSC) and the saccharification of structural carbohydrate (SC) could significantly increase ethanol conversion rate. Genetic gains for these traits are tributary to the availability of screening techniques for the precise identification of superior genotypes with increased potential for the production of fermentable carbohydrates. When assessing the genetic variability of parameters linked to cellulosic ethanol production (concentrations of NSC and SC), our results showed a large genetic variability within and among winter hardy- and biomass-type alfalfa cultivars (Duceppe et al. 2012). We also developed an efficient enzymatic assay to measure alfalfa stem degrade-ability, based on the quantity of glucose released by a customized commercially available enzyme cocktail. Despite its robustness, this test is labour intensive, thus limiting analytical capabilities. Near-infrared reflectance spectroscopy (NIRS) was previously shown to successfully predict enzyme released glucose in corn stover (Lewis et al. 2010). This approach allowed us to screen a large number of lignified alfalfa stem samples and to identify superior genotypes. Our objective was to determine if it is possible to develop alfalfa cultivars with superior cell wall (CW) degradability

Les parcs scientifiques du Québec : la perspective des entreprises : rapport de recherche

RÉSUMÉ: Cette recherche, financée par la Ville de Lévis, vise à avancer les connaissances sur les facteurs de succès des entreprises établies dans un parc scientifique. Afin de bien comprendre ces facteurs de succès, 12 entrevues semi-dirigées ont été menées entre septembre 2016 et avril 2017 auprès d’entreprises, d’organismes gouvernementaux et d’acteurs du milieu académique établis dans les parcs scientifiques du Québec, au Canada. Une approche exploratoire a été adoptée afin de réaliser cette recherche. En effet, une démarche inductive permet de mieux comprendre un phénomène, tel que la dynamique d’un parc scientifique. Les résultats présentés dans ce document traitent premièrement des diverses définitions du concept de parc scientifique ainsi que du portrait des parcs scientifiques au Québec. Les motivations des entreprises à s’établir dans un parc scientifique, leurs attentes face à leur parc scientifique ainsi que les incitatifs mis en place par les parcs seront ensuite présentés. Les résultats des entrevues ont permis d’identifier les effets des parcs scientifiques sur chacune des phases du processus d’innovation (Tiwari, 2007) : conception, développement et marketing. L’analyse de ces résultats permettra finalement d’identifier les facteurs de succès des entreprises établies dans les parcs scientifiques. Bref, les résultats de cette recherche permettent de fournir des pistes de réflexion pour la gestion des parcs scientifiques ainsi que pour les entreprises qui souhaitent s’établir dans un parc scientifique. -- ABSTRACT: This research, funded by the City of Lévis, aims to advance knowledge on the success factors of businesses established in a science park. In order to fully understand these success factors, 12 semi-structured interviews were conducted between September 2016 and April 2017 with businesses, government agencies and academic stakeholders in science parks in the province of Québec, Canada. An exploratory approach was adopted to carry out this research. Indeed, an inductive approach allows a better understanding of a phenomenon, such as the dynamics of a science park. The results presented in this document firstly deal with the various definitions of the concept of a science park as well as the portrait of the science parks in the province of Québec. The motivations of businesses to establish themselves in a science park, their expectations of their science park and the incentives proposed by the parks will be presented. The results of the interviews identified the effects that the science parks have on each phase of the innovation process (Tiwari, 2007): conception, implementation and marketing. The analysis of these results will ultimately identify the success factors of businesses established in science parks. In short, the results of this research help to provide insights for the management of science parks as well as for businesses wishing to establish themselves in a science park

Microscopie à deux photons pour l’imagerie cellulaire fonctionnelle : avantages et enjeux. ou Un photon c’est bien… mais deux c’est mieux !

L’observation de la dynamique des événements moléculaires dans la cellule in situ présente une série de défis, notamment la capacité de suivre ces événements avec le maximum de résolution spatiale et temporelle tout en minimisant l’interférence avec la biologie du tissu et de la cellule. L’exploitation récente d’approches fondées sur l’optique non-linéaire, telle que la microscopie par balayage laser de fluorescence produite par excitation à deux photons, a permis de faire des progrès énormes dans ce domaine, notamment parce qu’elle permet de faire des mesures dans un espace très confiné à l’intérieur du tissu intact et à des profondeurs inaccessibles avec la microscopie linéaire conventionnelle. En minimisant l’excitation indésirable du tissu en dehors du point focal, on améliore la résolution et la sensibilité, on simplifie le système optique et on minimise la phototoxicité. Ces avantages sont à la source du succès de la microscopie à deux photons pour l’imagerie cellulaire fonctionnelle. Des percées récentes en optique/photonique permettent d’envisager d’améliorer davantage la résolution spatiale et temporelle de ce type d’imagerie et la capacité de sonder encore plus profondément dans le tissu pour repousser les limites de la biochimie fonctionnelle et de la biologie cellulaire actuelles.One of the main challenges of modern biochemistry and cell biology is to be able to observe molecular dynamics in their functional context, i.e. in live cells in situ. Thus, being able to track ongoing molecular events with maximal spatial and temporal resolution (within subcellular compartments), while minimizing interference with tissue biology, is key to future developments for in situ imaging. The recent use of non-linear optics approaches in tissue microscopy, made possible in large part by the availability of femtosecond pulse lasers, has allowed major advances on this front that would not have been possible with conventional linear microscopy techniques. Of these approaches, the one that has generated most advances to date is two-photon laser scanning fluorescence microscopy. While this approach does not really provide improved resolution over linear microscopy in non absorbing media, it allows us to exploit a window of low absorbance in live tissue in the near infrared range. The end result is much improved tissue penetration, minimizing unwanted excitation outside the focal area, which yields an effective improvement in resolution and sensitivity. The optical system is also simplified and, more importantly, phototoxicity is reduced. These advantages are at the source of the success of two-photon microscopy for functional cellular imaging in situ. Yet, we still face further challenges, reaching the limits of resolution that conventional optics can offer. Here we review some recent advances in optics/photonics approaches that hold promises to improve our ability to probe the tissue in finer areas, at faster speed, and deeper into the tissue. These include super-resolution techniques, introduction of non paraxial optics in microscopy and use of amplified femtosecond lasers, yielding enhanced spatial and temporal resolution as well as tissue penetration

The Expectations of Businesses Settled in a Science Park

Science parks are created to support the development and growth of knowledge-based businesses and to foster the economic development of a region. Based on an exploratory qualitative study, this research project aims, firstly, to understand the expectations of businesses established in science parks, which is not very well documented in the literature and, secondly, to highlight the motivations of a business to settle in a science park. In order to do so, the research is based on a constructivist approach. Twelve semi-structured interviews were conducted between September 2016 and April 2017 with managers of organizations established in seven science parks in the province of Quebec, Canada. The analysis these interviews identified six major motivations of businesses to settle in a science park. It also revealed eleven major expectations of the science park's contributions for a business established. As a contribution, this research provides some recommendations not only for the managers of science parks, but also for the managers of businesses who want to be established in a science park. This research provides insights for science park managers about the incentives to set up to attract new business and about the support to provide for the business established in a science park in their development

Increased Sugar Concentration with PM-Cutting and Wide Swathing Improves Alfalfa Silage Fermentation

Extensive protein degradation during silage fermentation reduces the efficiency of N utilization by ruminants and excess N is excreted in the environment. Forage nonstructural carbohydrates (NSC) represent the main source of readily fermentable energy for lactic bacteria during silage fermentation. Increasing forage NSC concentration can enhance silage fermentation, lactic acid production, and the decline in pH with an overall reduction in the extent of protein degradation. The NSC concentration increases during the day in alfalfa (Medicago sativa L.) to reach a maximum by the end of the afternoon. Under good wilting conditions, PM-cut alfalfa wilted in wide swaths had a greater NSC concentration than AM-cut alfalfa (Morin et al. 2012). Our objective was to study the effect of PM cutting and wide swathing on alfalfa silage quality attributes

High-Sugar Alfalfa for Dairy Cows

Alfalfa proteins are extensively degraded during wilting, silage fermentation, and in the rumen. To efficiently use alfalfa non protein N, rumen microbes need a readily available energy source such as nonstructural carbohydrates (NSC); otherwise, surplus N in the form of rumen ammonia is converted into urea and excreted in the environment. Increasing the NSC concentration of alfalfa was thus the focus of our research program. Our objectives were to assess the impact of high NSC alfalfa on digestibility and microbial protein synthesis measured in vitro, and on ingestion, rumen metabolism, N use efficiency, and dairy cow performance. Increasing NSC concentration of alfalfa significantly enhanced in vitro dry matter (DM) digestibility and decreased NH3-N concentration in rumen fluid. An increase of 23 g/kg in alfalfa NSC concentration can improve forage DM intake (+5 %) and energy corrected milk production (+8 %). Feeding high-NSC alfalfa led to a higher rumen pH, suggesting that sugars do not cause rumen acidosis, and to a lower milk urea N (MUN) indicating an improvement in N utilization. Increasing NSC concentration of alfalfa is a low-cost tool to improve its utilisation in dairy rations and potentially mitigate the environmental footprint of milk production

Improving Forage Nonstructural Carbohydrates through Management and Breeding

Nonstructural carbohydrates (NSC) are an important source of readily fermentable energy available to rumen microbes. Limited concentrations of readily available energy in forages combined with fast and intensive protein degradation contribute to poor N use efficiency by dairy cows and other ruminants. Increasing NSC in forages has been shown to improve intake, milk yield, and N use efficiency (Brito et al. 2009). We assessed several strategies to increase forage NSC accumulation, including PM-cutting, species selection and genetic improvement

Efficacy of Synaptic Inhibition Depends on Multiple, Dynamically Interacting Mechanisms Implicated in Chloride Homeostasis

Chloride homeostasis is a critical determinant of the strength and robustness of inhibition mediated by GABAA receptors (GABAARs). The impact of changes in steady state Cl− gradient is relatively straightforward to understand, but how dynamic interplay between Cl− influx, diffusion, extrusion and interaction with other ion species affects synaptic signaling remains uncertain. Here we used electrodiffusion modeling to investigate the nonlinear interactions between these processes. Results demonstrate that diffusion is crucial for redistributing intracellular Cl− load on a fast time scale, whereas Cl−extrusion controls steady state levels. Interaction between diffusion and extrusion can result in a somato-dendritic Cl− gradient even when KCC2 is distributed uniformly across the cell. Reducing KCC2 activity led to decreased efficacy of GABAAR-mediated inhibition, but increasing GABAAR input failed to fully compensate for this form of disinhibition because of activity-dependent accumulation of Cl−. Furthermore, if spiking persisted despite the presence of GABAAR input, Cl− accumulation became accelerated because of the large Cl− driving force that occurs during spikes. The resulting positive feedback loop caused catastrophic failure of inhibition. Simulations also revealed other feedback loops, such as competition between Cl− and pH regulation. Several model predictions were tested and confirmed by [Cl−]i imaging experiments. Our study has thus uncovered how Cl− regulation depends on a multiplicity of dynamically interacting mechanisms. Furthermore, the model revealed that enhancing KCC2 activity beyond normal levels did not negatively impact firing frequency or cause overt extracellular K− accumulation, demonstrating that enhancing KCC2 activity is a valid strategy for therapeutic intervention