Investigation of limiting metabolic steps in the utilization of xylose by recombinant Saccharomyces cerevisiae using metabolic engineering

A Saccharomyces cerevisiae screening strain was designed by combining multiple genetic modifications known to improve xylose utilization with the primary objective of enhancing xylose growth and fermentation in xylose isomerase (XI)-expressing strains. Strain TMB 3045 was obtained by expressing the XI gene from Thermus thermophilus in a strain in which the GRE3 gene coding for aldose reductase was deleted, and the genes encoding xylulokinase (XK) and the enzymes of the non-oxidative pentose phosphate pathway (PPP) [transaldolase (TAL), transketolase (TKL), ribose 5-phosphate ketol-isomerase (RKI) and ribulose 5-phosphate epimerase (RPE)] were overexpressed. A xylose-growing and fermenting strain (TMB 3050) was derived from TMB 3045 by repeated cultivation on xylose medium. Despite its low XI activity, TMB 3050 was capable of aerobic xylose growth and anaerobic ethanol production at 30 degrees C. The aerobic xylose growth rate reached 0.17 l/h when XI was replaced with xylose reductase (XR) and xylitol dehydrogenase (XDH) genes expressed from a multicopy plasmid, demonstrating that the screening system was functional. Xylose growth had not previously been detected in strains in which the PPP genes were not overexpressed or when overexpressing the PPP genes but having XR and XDH genes chromosomally integrated. This demonstrates the necessity to simultaneously increase the conversion of xylose to xylulose and the metabolic steps downstream of xylulose for efficient xylose utilization in S. cerevisiae.     

Barriers and drivers for sustainable building

What are the actual barriers and drivers for sustainable building? A literature review, interviews and case studies are presented to address this question. Sustainable building is not hindered by a lack of technologies and assessment methods, but is instead beset with organizational and procedural difficulties entailed by the adoption of new methods. New technologies are resisted because they require process changes entailing risks and unforeseen costs. These hindrances can be reduced by learning what kind of decision-making phases, new tasks, actors, roles and ways of networking are needed. The barriers are outlined as steering mechanisms, economics, a lack of client understanding, process (procurement and tendering, timing, cooperation and networking), and underpinning knowledge (knowledge and common language, the availability of methods and tools, innovation). The most important actions to promote sustainable building are the development of the awareness of clients about the benefits of sustainable building, the development and adoption of methods for sustainable building requirement management, the mobilization of sustainable building tools, the development of designers' competence and team working, and the development of new concepts and services. The interviews and case studies were carried out in Finland, but the results may be applicable or interesting to other countries as well.

Quels sont les obstacles et les vecteurs actuels en matière de construction de bâtiments durables ? Il est présenté une analyse bibliographique, des entretiens et des études de cas afin d'examiner cette question. La construction de bâtiments durables n'est pas entravée par un manque de technologies et de méthodes d'évaluation, mais est plutôt en butte à de multiples difficultés organisationnelles et procédurales occasionnées par l'adoption de méthodes nouvelles. Il y a une résistance aux nouvelles technologies parce qu'elles nécessitent des modifications des processus entraînant des risques et des coûts imprévus. Il est possible de réduire ces entraves en faisant l'apprentissage de ce qui est nécessaire, s'agissant des phases de prise de décision, des nouvelles tâches, des nouveaux acteurs, des nouvelles fonctions et des nouveaux modes de mise en réseau. Les obstacles passés en revue concernent les mécanismes de pilotage, l'économie, un manque de compréhension des clients, les processus (achats et appels d'offres, timing, coopération et mise en réseau) et les connaissances de base (connaissances et langage commun, disponibilité des méthodes et des outils, innovation). Les mesures les plus importantes pour promouvoir la construction de bâtiments durables sont le développement de la sensibilisation des clients aux avantages d'un bâtiment durable, le développement et l'adoption de méthodes de gestion des exigences propres aux bâtiments durables, la mobilisation des outils de construction durable, le développement des compétences des concepteurs et du travail d'équipe, et le développement de concepts et de services nouveaux. Les entretiens et les études de cas ont été réalisés en Finlande, mais les résultats peuvent également s'appliquer à d'autres pays ou présenter un intérêt pour d'autres pays.

Mots clés: obstacles, industrie du bâtiment, vecteurs, gestion, changement organisationnel, professionnalisme, processus de construction durable, bâtiment durable     

Lipidomic Profiling of Chylomicron Triacylglycerols in Response to High Fat Meals

Using lipidomic methodologies the impact that meal lipid composition and metabolic syndrome (MetS) exerts on the postprandial chylomicron triacylglycerol (TAG) response was examined. Males (9 control; 11 MetS) participated in a randomised crossover trial ingesting two high fat breakfast meals composed of either dairy-based foods or vegetable oil-based foods. The postprandial lipidomic molecular composition of the TAG in the chylomicron-rich (CM) fraction was analysed with tandem mass spectrometry coupled with liquid chromatography to profile CM TAG species and targeted TAG regioisomers. Postprandial CM TAG concentrations were significantly lower after the dairy-based foods compared with the vegetable oil-based foods for both control and MetS subjects. The CM TAG response to the ingested meals involved both significant and differential depletion of TAG species containing shorter- and medium-chain fatty acids (FA) and enrichment of TAG molecular species containing C16 and C18 saturated, monounsaturated and diunsaturated FA. Furthermore, there were significant changes in the TAG species between the food TAG and CM TAG and between the 3- and 5-h postprandial samples for the CM TAG regioisomers. Unexpectedly, the postprandial CM TAG concentration and CM TAG lipidomic responses did not differ between the control and MetS subjects. Lipidomic analysing of CM TAG molecular species revealed dynamic changes in the molecular species of CM TAG during the postprandial phase suggesting either preferential CM TAG species formation and/or clearance.     

Maternal Affection Moderates the Impact of Psychological Control on a Child's Mathematical Performance.

This study investigated the extent to which mothers' psychological control predicts their children's mathematical performance during the children's transition from preschool to primary school over and above the impact of maternal affection and behavioral control. Also investigated was the extent to which maternal affection and behavioral control moderate the impact of mothers' psychological control. Children 5-6 years old at baseline (N=196) were followed up 6 times to measure their performance in mathematics over a 3-year period from preschool to 2nd grade. Mothers were asked to fill in a questionnaire measuring their parenting styles once every year over the 3-year period. A high level of psychological control exercised by mothers predicted their children's slow progress in mathematics. However, this impact was particularly evident among those children whose mothers reported a high level of affection. No evidence was found that children's mathematical performance had any effect on their mothers' parenting styles. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of enzyme‐aided pressing on anthocyanin yield and profiles in bilberry and blackcurrant juices

Bilberries (Vaccinium myrtillus) and blackcurrants (Ribes nigrum) were treated with extensive dosages of commercial cell wall degrading enzyme preparations, i.e. Econase CE, Pectinex Ultra SP‐L, Pectinex Smash, Pectinex BE 3‐L and Biopectinase CCM. The enzymes were dosed based on the polygalacturonase activity. The juice yield was improved in both berries as a result of the enzymatic treatment. The improvement was more pronounced with blackcurrants owing to their thicker cell walls. The impact of the enzymatic treatment on anthocyanins present in the juices was investigated using HPLC‐DAD. The enzyme preparations affected the contents and composition of anthocyanins in the juices. Pectinex Ultra SP‐L, Pectinex Smash, Pectinex BE 3‐L and Biopectinase CCM increased the total content of anthocyanins by 13–41% in the bilberry juices and by 18–29% in the blackcurrant juices. Econase CE, however, produced a dramatic decrease in the total anthocyanin content in the bilberry juice due to its enzyme profile, whereas no such effect was observed with the blackcurrant juice. All the enzyme mixtures tested produced a total or extensive loss of anthocyanidin galactosides in bilberry juice. Commercial enzyme preparations used in the production of berry juices can improve extraction of anthocyanins into the juice. However, they may effectively hydrolyse certain glycosides and thus affect the profile of extracted anthocyanins. Copyright © 2005 Society of Chemical Industry     

The Role of Household Food Waste in Comparing Environmental Impacts of Packaging Alternatives

This paper examines the environmental impacts of food waste and the influence that packaging alternatives can have on causing food waste. This paper presents the results of three life cycle assessment case studies on packed food products. The life cycle assessments were conducted for ham, dark bread and Soygurt drink (fermented soy‐based drink). In each case study, the environmental impacts of the products were assessed with different assumptions about the packaging sizes and alternative materials. The studies especially considered the environmental impacts resulting from food waste generated by consumers as a function of the variable packaging options. The food waste of other parts of the production chain of the studied products was also taken into account. A consumer survey was carried out to estimate the amounts of product waste generated in Finnish households connected to the three investigated products. The environmental impacts of the food products, household food waste and packaging were modelled by scenarios with varying rates of household food waste and different waste management options. The results indicated that the significance of the production and post‐consumer life of packaging was relatively low for climate change, eutrophication and acidification, in comparison with the production chain of the ham, dark bread and Soygurt. According to the results, packaging solutions that minimize the waste generation in households as well as in distribution and retail will lead to the lowest environmental impacts of the entire product‐packaging chain. Therefore, it is important to design packages that protect the food properly and allow the consumer to use the product fully. Copyright © 2013 John Wiley & Sons, Ltd.     

Application of a Bayesian model for the quantification of the European methodology for qualification of non-destructive testing

The European methodology for qualification of non-destructive testing is a well-established approach adopted by nuclear utilities in many European countries. According to this methodology, qualification is based on a combination of technical justification and practical trials. The methodology is qualitative in nature, and it does not give explicit guidance on how the evidence from the technical justification and results from trials should be weighted. A Bayesian model for the quantification process was presented in a previous paper, proposing a way to combine the “soft” evidence contained in a technical justification with the “hard” evidence obtained from practical trials.This paper describes the results of a pilot study in which such a Bayesian model was applied to two realistic Qualification Dossiers by experienced NDT qualification specialists. At the end of the study, recommendations were made and a set of guidelines was developed for the application of the Bayesian model.     

An Experimentally Simple Method for Measuring Sorption Isotherms

We describe a simple, yet practical and precise, way of measuring sorption isotherms with each sample in its own glass jar with a saturated salt solution. The measurements are done with below-balance weighing and with the sample kept inside the closed jar during the whole measurement period, providing constant relative humidity (RH) conditions. The technique has been tested on microcrystalline cellulose and bentonite clay. The agreement with literature values was good; the differences seen for bentonite at high RH are discussed in terms of the slow attainment of equilibrium for this material.     

Energy and transport in comparison: Immaterialisation,dematerialisation and decarbonisation in the EU15 between 1970 and 2000

This article compares the development of transport and energy use with a focus on carbon dioxide (CO₂) emissions in the EU15 countries between 1960 and 2000, and separately by each individual EU country between 1970 and 2000. Based on a review on the literature, immaterialisation can be defined as the reduction of energy intensity and transport intensity; dematerialisation can be defined as the reduction in carbon intensity of energy production and the carbon intensity of transport; decarbonisation can be defined as the reduction in (total and transport) carbon intensity of the whole economy. Although there is a clear pattern of reduction in energy intensity of the economy and carbon intensity of energy production, a similar pattern cannot be found in transport. Neither the transport intensity of the economy nor the carbon intensity of transport has been reduced. In particular, freight transport intensity has grown between 1985 and 2000. Data presented by country have shown even more variation. The EU15 countries were aggregated into six groups by cluster analysis to establish the different patterns on each of the three measures. It is concluded that the EU15 countries will have problems in achieving the EU White Paper target of decoupling transport growth from economic growth and the Kyoto target of reducing total CO₂ emissions by 8% from the 1990 level between 2008 and 2012. However, there are some weak signals suggesting a more sustainable passenger transport system.     

Efficient hybrid methods for global continuous optimization based on simulated annealing

We introduce several hybrid methods for global continuous optimization. They combine simulated annealing and a local proximal bundle method. Traditionally, the simplest hybrid of a global and a local solver is to call the local solver after the global one, but this does not necessarily produce good results. Besides, using efficient gradient-based local solvers implies that the hybrid can only be applied to differentiable problems. We show several ways how to integrate the local solver as a genuine part of simulated annealing to enable both efficient and reliable solution processes. When using the proximal bundle method as a local solver, it is possible to solve even nondifferentiable problems. The numerical tests show that the hybridization can improve both the efficiency and the reliability of simulated annealing.