www.inequalityin.eu - Ungleichheit in Europa sichtbar machen

Das Ziel des Projektes ist es, unterschiedliche Lebensrealitäten und Spannungsfelder in der Europäischen Union sichtbar zu machen. Der Fokus liegt dabei auf Lohnunterschieden nach Berufen und Ländern. Mittels interaktiver Website wird ein niedrigschwelliger Einstieg in das Thema geboten und diese Unterschiede für eine breite Öffentlichkeit erforschbar gemacht. Das Onlineprojekt lädt zum selbstständigen Entdecken von Inhalten ein, beispielsweise von Lohndifferenzen nach Geschlecht oder typischen Berufen (Ärzt_innen, Reinigungskräfte, Büroangestellte, etc.) Begleitet wird dieser Prozess durch die Darstellung von ökonomischen und institutionellen Rahmenbedingungen, etwa Lebenserwartung oder Schadstoffbelastung. Das Projekt bietet für diese Lebenslagen und -realitäten Lösungsvorschläge an, die zu einer Verbesserung der europäischen Integration beitragen können

Quantitative evaluation of yeast's requirement for glycerol formation in very high ethanol performance fed-batch process

<p>Abstract</p> <p>Background</p> <p>Glycerol is the major by-product accounting for up to 5% of the carbon in <it>Saccharomyces cerevisiae </it>ethanolic fermentation. Decreasing glycerol formation may redirect part of the carbon toward ethanol production. However, abolishment of glycerol formation strongly affects yeast's robustness towards different types of stress occurring in an industrial process. In order to assess whether glycerol production can be reduced to a certain extent without jeopardising growth and stress tolerance, the yeast's capacity to synthesize glycerol was adjusted by fine-tuning the activity of the rate-controlling enzyme glycerol 3-phosphate dehydrogenase (GPDH). Two engineered strains whose specific GPDH activity was significantly reduced by two different degrees were comprehensively characterized in a previously developed Very High Ethanol Performance (VHEP) fed-batch process.</p> <p>Results</p> <p>The prototrophic strain CEN.PK113-7D was chosen for decreasing glycerol formation capacity. The fine-tuned reduction of specific GPDH activity was achieved by replacing the native <it>GPD1 </it>promoter in the yeast genome by previously generated well-characterized <it>TEF </it>promoter mutant versions in a <it>gpd2</it>Δ background. Two <it>TEF </it>promoter mutant versions were selected for this study, resulting in a residual GPDH activity of 55 and 6%, respectively. The corresponding strains were referred to here as <it>TEFmut7 </it>and <it>TEFmut2</it>. The genetic modifications were accompanied to a strong reduction in glycerol yield on glucose; the level of reduction compared to the wild-type was 61% in <it>TEFmut7 </it>and 88% in <it>TEFmut2</it>. The overall ethanol production yield on glucose was improved from 0.43 g g^-1in the wild type to 0.44 g g^-1measured in <it>TEFmut7 </it>and 0.45 g g^-1in <it>TEFmut2</it>. Although maximal growth rate in the engineered strains was reduced by 20 and 30%, for <it>TEFmut7 </it>and <it>TEFmut2 </it>respectively, strains' ethanol stress robustness was hardly affected; i.e. values for final ethanol concentration (117 ± 4 g L^-1), growth-inhibiting ethanol concentration (87 ± 3 g L^-1) and volumetric ethanol productivity (2.1 ± 0.15 g l^-1h^-1) measured in wild-type remained virtually unchanged in the engineered strains.</p> <p>Conclusions</p> <p>This work demonstrates the power of fine-tuned pathway engineering, particularly when a compromise has to be found between high product yield on one hand and acceptable growth, productivity and stress resistance on the other hand. Under the conditions used in this study (VHEP fed-batch), the two strains with "fine-tuned" <it>GPD1 </it>expression in a <it>gpd2</it>Δ background showed slightly better ethanol yield improvement than previously achieved with the single deletion strains <it>gpd1</it>Δ or <it>gpd2</it>Δ. Although glycerol reduction is known to be even higher in a <it>gpd1</it>Δ <it>gpd2</it>Δ double deletion strain, our strains could much better cope with process stress as reflected by better growth and viability.</p

Improved linkage analysis of Quantitative Trait Loci using bulk segregants unveils a novel determinant of high ethanol tolerance in yeast

Background: Bulk segregant analysis (BSA) coupled to high throughput sequencing is a powerful method to map genomic regions related with phenotypes of interest. It relies on crossing two parents, one inferior and one superior for a trait of interest. Segregants displaying the trait of the superior parent are pooled, the DNA extracted and sequenced. Genomic regions linked to the trait of interest are identified by searching the pool for overrepresented alleles that normally originate from the superior parent. BSA data analysis is non-trivial due to sequencing, alignment and screening errors. Results: To increase the power of the BSA technology and obtain a better distinction between spuriously and truly linked regions, we developed EXPLoRA (EXtraction of over-rePresented aLleles in BSA), an algorithm for BSA data analysis that explicitly models the dependency between neighboring marker sites by exploiting the properties of linkage disequilibrium through a Hidden Markov Model (HMM). Reanalyzing a BSA dataset for high ethanol tolerance in yeast allowed reliably identifying QTLs linked to this phenotype that could not be identified with statistical significance in the original study. Experimental validation of one of the least pronounced linked regions, by identifying its causative gene VPS70, confirmed the potential of our method. Conclusions: EXPLoRA has a performance at least as good as the state-of-the-art and it is robust even at low signal to noise ratio's i.e. when the true linkage signal is diluted by sampling, screening errors or when few segregants are available

Saccharomyces cerevisiae goes through distinct metabolic phases during its replicative lifespan

A comprehensive description of the phenotypic changes during cellular aging is key towards unraveling its causal forces. Previously, we mapped age-related changes in the proteome and transcriptome (Janssens et al., 2015). Here, employing the same experimental procedure and model-based inference, we generate a comprehensive account of metabolic changes during the replicative life of Saccharomyces cerevisiae. With age, we found decreasing metabolite levels, decreasing growth and substrate uptake rates accompanied by a switch from aerobic fermentation to respiration, with glycerol and acetate production. The identified metabolic fluxes revealed an increase in redox cofactor turnover, likely to combat increased production of reactive oxygen species. The metabolic changes are possibly a result of the age-associated decrease in surface area per cell volume. With metabolism being an important factor of the cellular phenotype, this work complements our recent mapping of the transcriptomic and proteomic changes towards a holistic description of the cellular phenotype during aging

Application of novel metabolic engineering tools for engineering of the complex trait of glycerol yield in Saccharomyces cerevisiae

The yeast, Saccharomyces cerevisiae is still the prime species used in ethanol production. Traditionally, ethanol has been produced from raw materials such as sugar cane or sugar beet and starch from corn or other grains. Future expansion of ethanol production are planed its use as a biofuel requiring the utilization new non- food resources, particularly lignocelluloses. In the present and future ethanol production process, the expenditure for the raw material is a significant cost factor. Although industrial yeast strains are very efficient in producing ethanol, the current ethanol yield (90 - 93% of the theoretical maximum) could in principle be further improved. Particularly, the synthesis of glycerol, a major by-product of alcoholic fermentation, has been regarded as a wasteful process. The overall goal of this project was to develop novel industrial yeast strains, which are able to produce more ethanol from the traditional and future raw materials by reducing the yield of the undesirable by-product glycerol. The challenge herein is that glycerol serves different important physiological functions such as redox balancing and osmotic stress tolerance. In this project, two alternative avenues were used to identify a genetic configuration for a low glycerol producer strain. The first approach was a rational engineering strategy aiming to finely tune the activity of the rate-limiting enzyme of glycerol synthesis, the glycerol 3-phosphate dehydrogenase. The basic idea here was to gradually reduce the expression of the corresponding genes, GPD1 and GPD2, by replacing their native promoters through mutated low strength TEF1 promoter versions. After the promoter exchange, the mutants were characterized for their residual glycerol formation, fermentation and growth. In the second approach, the genetic configuration of wild-type yeast with low glycerol yields were analyzed. Its genetic determinants, which cause the low glycerol phenotype were identified, using an advanced genetic mapping methodology base on next-generation pooled segregants whole-genome sequence analysis. The four genes, GPD1 SSK1 SMP1 and HOT1 were identified, which harbored mutations linked to the 'low glycerol' phenotype. The SSK1 allele of the superior low producing glycerol strain, ssk1E330N...K356N was subsequently used as novel gene tool for targeted genetic improvement of the ethanol yield of a frequently used ethanol production strain with minimal risk of affecting its other industrially important traits.status: publishe

Solidarisch Handeln: Konzeptionen, Ursachen und Implikationen

Der Begriff der „Solidarität“ bleibt, sowohl in wissenschaftlichen Auseinandersetzungen als auch in der praktisch-politischen Verwendung, zumeist diffus und weitgehend unbestimmt. Insofern stellt sich die Frage, inwiefern ein unscharfes Konzept wie jenes der Solidarität als normativer Bezugspunkt individuellen Handelns oder politischer Entscheidungsfindung taugt. Vor diesem Hintergrund versucht der vorliegende Beitrag zu einer Präzisierung des Solidaritätsbegriffs beizutragen, indem verschiedene Ursachen und Motive solidarischen Handelns gegenübergestellt und verglichen werden. Eine Anwendung der sich hieraus ergebenden Typologie auf drei Bereiche (Frauenpolitik, Gewerkschaften und Entwicklungszusammenarbeit) verdeutlicht, wie sich verschiedene Solidaritätskonzepte in unterschiedlichen politischen Positionen und Strategien manifestieren. Am Ende dieser Analyse steht die Frage nach einer fortschrittlich-emanzipativen („progressiven“) Deutung des Solidaritätsbegriffs und dessen politischen Implikationen

Sozialer Fortschritt in offenen Gesellschaften des 21. Jahrhunderts: Unrealistische Utopie oder notwendige Möglichkeit?

Die offene Gesellschaft ist ein wesentlicher Kulminationspunkt der Aufklärung und basiert auf der Vorstellung, dass sozialer Fortschritt durch eine gewaltfreie, wissenschaftsgeleitete und demokratische Auseinandersetzung, über gesellschaftliche Konfliktmomente, gefördert werden kann. Während dieses abstrakte Versprechen in der Nachkriegszeit zumindest teilweise eingelöst werden konnte, sehen sich Gesellschaften im 21. Jahrhundert mit neuen Entwicklungen konfrontiert, die bestehende offene Gesellschaften vor zusätzliche Herausforderungen stellen und zugleich die Entstehung neuer offener Gesellschaften erschweren. Vor diesem Hintergrund versucht dieser Beitrag am Beispiel dreier solcher Entwicklungen - dem globalen Standortwettbewerb, der steigenden ökonomischen Ungleichheit und dem Klimawandel - auszuloten, in welchem Maße diese spezifischen Herausforderungen des 21. Jahrhunderts mit jenen Werthaltungen in Zusammenhang stehen, die als konstitutiv oder besonders relevant für die Erhaltung und Entstehung offener Gesellschaften gelten