From the phosphoenolpyruvate phosphotransferase system (PTS) to selfish metabolism: a story retraced in Pseudomonas putida

Although DNA is the ultimate repository of biological information, deployment of its instructions is constrained by the metabolic and physiological status of the cell. To this end, bacteria have evolved intricate devices that connect exogenous signals (e.g. nutrients, physicochemical conditions) with endogenous conditions (metabolic fluxes, biochemical networks) that coordinately influence expression or performance of a large number of cellular functions. The phosphoenolpyruvate:carbohydrate-phosphotransferase system (PTS) is a bacterial multi-protein phosphorylation chain which computes extracellular (e.g. sugars) and intracellular (e.g. phosphoenolpyruvate, nitrogen) signals and translates them into post-translational regulation of target activities through protein-protein interactions. The PTS of Pseudomonas putida KT2440 encompasses one complete sugar (fructose)-related system and the 3 enzymes that form the so-called nitrogen-related PTS (PTSNtr), which lacks connection to transport of substrates. These two PTS branches cross-talk to each other, as the product of the fruB gene (a polyprotein EI-HPr-EIIA) can phosphorylate PtsN (EIIANtr) in vivo. This gives rise to a complex actuator device where diverse physiological inputs are ultimately translated into phosphorylation or not of PtsN (EIIANtr) which, in turn, checks the activity of key metabolic and regulatory proteins. Such a control of bacterial physiology highlights the prominence of biochemical homeostasis over genetic ruling –and not vice versa.This study was supported by the BIO Program of the Spanish Ministry of Science and Innovation, the ST-FLOW and ARYSIS Contracts of the EU, the ERANET-IB Program and the PROMT Project of the CAMPeer reviewe

A mass-conserving sparse grid combination technique with biorthogonal hierarchical basis functions for kinetic simulations

The exact numerical simulation of plasma turbulence is one of the assets and challenges in fusion research. For grid-based solvers, sufficiently fine resolutions are often unattainable due to the curse of dimensionality. The sparse grid combination technique provides the means to alleviate the curse of dimensionality for kinetic simulations. However, the hierarchical representation for the combination step with the state-of-the-art hat functions suffers from poor conservation properties and numerical instability. The present work introduces two new variants of hierarchical multiscale basis functions for use with the combination technique: the biorthogonal and full weighting bases. The new basis functions conserve the total mass and are shown to significantly increase accuracy for a finite-volume solution of constant advection. Further numerical experiments based on the combination technique applied to a semi-Lagrangian Vlasov--Poisson solver show a stabilizing effect of the new bases on the simulations

Ökonomisierung universitärer Lehre?

In der Wissenschafts- und Hochschulforschung wird intensiv über eine Ökonomisierung der Forschung als Auswirkung von kompetitiven Mittelvergaben wie der Exzellenz-Initiative diskutiert. Selten wird neben der Rolle als ForschendeR die als LehrendeR fokussiert, die ebenfalls zum Kernbereich der akademischen Tätigkeit zählt.  Dieser Beitrag wirft die Frage auf, wie sich zentrale Wandlungstendenzen in den Rahmenbedingungen universitärer Lehre, vor allem durch den Qualitätspakt Lehre (QPL),  im Governance-Regime von Hochschulen auswirken. Ausgehend von der These, dass der QPL zu nicht-intendierten Folgen auf Universität und Lehre führt, werden am Beispiel des Lehrkonzepts ‚Forschendes Lernen‘  empirische Befunde diskutiert.  Diese lassen Parallelen zu den Debatten einer Ökonomisierung der Forschung erkennen

Lehrende sind Forschende: Die Lehrpraxis des "Forschenden Lernens" soziologisch betrachtet

Forschendes Lernen ist eines der zentralen hochschuldidaktischen Leitprinzipien zur Gestaltung des "shift from teaching to learning", das zunehmend von Hochschulen institutionell verankert wird. Es liegen zahlreiche empirische Untersuchungen zu Wirkungsweisen und Potenzialen des Formats für Studierende vor. Lehrende werden bislang vorrangig als Kontextfaktor betrachtet, der strukturelle Rahmenbedingungen umsetzt. Um die Ausgestaltung von Formaten Forschenden Lernens zu verstehen, scheint es sinnvoll, Lehrende in den Fokus zu rücken und das die akademische Tätigkeit prägende Spannungsfeld zwischen Forschung und Lehre zu betrachten. In ihrem Beitrag untersuchen Katharina Mojescik, Jessica Pflüger, Carla Scheytt und Martina Schmohr die vielfältige Lehrpraxis in der Umsetzung von Forschendem Lernen (auch im fachdisziplinären Vergleich) an der Ruhr-Universität Bochum (RUB) aus soziologischer Perspektive. Sie zeigen, dass sich Forschungsverständnis und -erfahrung in dem Lehrformat nicht nur widerspiegeln, sondern auch maßgeblich strategische Entscheidungen zur Lehrpraxis beeinflussen, woraus sich neue Ableitungen (auch) für die Hochschuldidaktik ergeben.Research-based learning is one of the central didactic principles of the "shift from teaching to learning", which is increasingly implemented by universities. While numerous empirical studies focus on the effects of research-based learning for students, the role of teachers in such formats has so far been neglected. Hitherto, teachers are primarily referred to as translators of structural conditions into teaching practice. In order to understand research-based learning more fully, this paper discusses how teachers and their academic identities influence their teaching practices. Based on a qualitative study, our paper examines teaching practices of research-based learning in a disciplinary comparison at one German university (Ruhr-University Bochum, RUB) from a sociological perspective. As we will show, disciplinary cultures and academic identities considerably influence teaching practices of research-based learning, which leads to implications for university didactics

Metabolic engineering of Halomonas elongata: Ectoine secretion is increased by demand and supply driven approaches

The application of naturally-derived biomolecules in everyday products, replacing conventional synthetic manufacturing, is an ever-increasing market. An example of this is the compatible solute ectoine, which is contained in a plethora of treatment formulations for medicinal products and cosmetics. As of today, ectoine is produced in a scale of tons each year by the natural producer Halomonas elongata. In this work, we explore two complementary approaches to obtain genetically improved producer strains for ectoine production. We explore the effect of increased precursor supply (oxaloacetate) on ectoine production, as well as an implementation of increased ectoine demand through the overexpression of a transporter. Both approaches were implemented on an already genetically modified ectoine-excreting strain H. elongata KB2.13 (ΔteaABC ΔdoeA) and both led to new strains with higher ectoine excretion. The supply driven approach led to a 45% increase in ectoine titers in two different strains. This increase was attributed to the removal of phosphoenolpyruvate carboxykinase (PEPCK), which allowed the conversion of 17.9% of the glucose substrate to ectoine. For the demand driven approach, we investigated the potential of the TeaBC transmembrane proteins from the ectoine-specific Tripartite ATP-Independent Periplasmic (TRAP) transporter as export channels to improve ectoine excretion. In the absence of the substrate-binding protein TeaA, an overexpression of both subunits TeaBC facilitated a three-fold increased excretion rate of ectoine. Individually, the large subunit TeaC showed an approximately five times higher extracellular ectoine concentration per dry weight compared to TeaBC shortly after its expression was induced. However, the detrimental effect on growth and ectoine titer at the end of the process hints toward a negative impact of TeaC overexpression on membrane integrity and possibly leads to cell lysis. By using either strategy, the ectoine synthesis and excretion in H. elongata could be boosted drastically. The inherent complementary nature of these approaches point at a coordinated implementation of both as a promising strategy for future projects in Metabolic Engineering. Moreover, a wide variation of intracelllular ectoine levels was observed between the strains, which points at a major disruption of mechanisms responsible for ectoine regulation in strain KB2.13.This work has been funded by the German Federal Ministry of Education and Research (BMBF) through project HOBBIT (031B03)

Adaptation to Varying Salinity in Halomonas elongata: Much More Than Ectoine Accumulation

The halophilic γ-proteobacterium Halomonas elongata DSM 2581 T thrives at salt concentrations well above 10 % NaCl (1.7 M NaCl). A well-known osmoregulatory mechanism is the accumulation of the compatible solute ectoine within the cell in response to osmotic stress. While ectoine accumulation is central to osmoregulation and promotes resistance to high salinity in halophilic bacteria, ectoine has this effect only to a much lesser extent in non-halophiles. We carried out transcriptome analysis of H. elongata grown on two different carbon sources (acetate or glucose), and low (0.17 M NaCl), medium (1 M), and high salinity (2 M) to identify additional mechanisms for adaptation to high saline environments. To avoid a methodological bias, the transcripts were evaluated by applying two methods, DESeq2 and Transcripts Per Million (TPM). The differentially transcribed genes in response to the available carbon sources and salt stress were then compared to the transcriptome profile of Chromohalobacter salexigens, a closely related moderate halophilic bacterium. Transcriptome profiling supports the notion that glucose is degraded via the cytoplasmic Entner-Doudoroff pathway, whereas the Embden-Meyerhoff-Parnas pathway is employed for gluconeogenesis. The machinery of oxidative phosphorylation in H. elongata and C. salexigens differs greatly from that of non-halophilic organisms, and electron flow can occur from quinone to oxygen along four alternative routes. Two of these pathways via cytochrome bo' and cytochrome bd quinol oxidases seem to be upregulated in salt stressed cells. Among the most highly regulated genes in H. elongata and C. salexigens are those encoding chemotaxis and motility proteins, with genes for chemotaxis and flagellar assembly severely downregulated at low salt concentrations. We also compared transcripts at low and high-salt stress (low growth rate) with transcripts at optimal salt concentration and found that the majority of regulated genes were down-regulated in stressed cells, including many genes involved in carbohydrate metabolism, while ribosome synthesis was up-regulated, which is in contrast to what is known from non-halophiles at slow growth. Finally, comparing the acidity of the cytoplasmic proteomes of non-halophiles, extreme halophiles and moderate halophiles suggests adaptation to an increased cytoplasmic ion concentration of H. elongata. Taken together, these results lead us to propose a model for salt tolerance in H. elongata where ion accumulation plays a greater role in salt tolerance than previously assumed

A novel methodological approach for group classification during fission of a semi-free-ranging group of Japanese macaques (Macaca fuscata)

The self-initiated split of a social group, known as fission, is a challenge faced by many group-living animals. The study of group fission and the social restructuring process in real time provides insights into the mechanism of this biologically important process. Previous studies on fission in Japanese macaques (Macaca fuscata) assigned individuals to newly reorganized groups mainly using behavioral observations and group attendance records based on periods before or after fission itself. Here, we present a novel framework for group classification during the process of fission that uses quantifiable behavioral variables and statistical analyses. The framework was tested on a group fission process at Affenberg Landskron (Austria), a park that housed around 160 semi-free-ranging Japanese macaques. The behavioral data were collected for 26 days during fission. We analyzed three behavioral developments recurrent in fissions in Japanese macaques, that is, independence of behavior, participation in group movements, and separation of nomadic ranges. These analyses were combined to assign individuals to different groups. Our study resulted in one main group (N = 33), one subgroup (N = 36) and 56 individuals whose group membership was still undefined. The demographic characteristics of these newly formed groups were comparable with those of fissioned groups in wild populations. Furthermore, we found that these newly forming groups showed early social dynamics of fission five months before group level movements, that is: grouping based on spatial proximity and spatial withdrawal of the subgroup to the periphery. These results underline the validity of our novel framework to study social dynamics in Japanese macaques during the process of fission. It represents an important addition to existing methods, and we recommend testing its scope in other primate societies

Father-son relationships in the stories „Ein Haus aus lauter Liebe“ and „Jäger des Spotts“ by Siegfried Lenz

Problemem tej pracy licencjackiej jest analiza konfliktów między ojcem, a synem w opowiadaniach „Ein Haus aus lauter Liebe“ ("Dom z czystej miłości") i „Jäger des Spotts” („Łowca kpiny”) Siegfrieda Lenza. Wybrałam ten temat, ponieważ w literaturze relacje rodzinne i kontakty interpersonalne są niewyczerpanym źródłem badań. W mojej pracy będę próbowała udowodnić czy ciężkie doświadczenia z dzieciństwa i zaginiona osoba ojca wpłynęły na twórczość Siegfrieda Lenza.Historie „Ein Haus aus lauter Liebe“ i „Jäger des Spotts“ pochodzą z kolekcji opowiadań „Geschichten aus dieser Zeit”(„Opowieści z tych czasów“). Dlaczego ta książka nosi taki tytuł? Ponieważ są to historie ponadczasowe. Opisane postacie mają te same problemy, co my w dzisiejszych czasach. Opowiadania, które będę badała opisują zaburzone relacje ojca z synem. Problem relacji rodzicielskich powtarza się w życiu każdego człowieka, bez względu na epokę.Istnieje wiele pytań dotyczący opowiadań Siegfrieda Lenza, na które należy odpowiedzieć. Relacje interpersonalne zazwyczaj odnoszą się do psychologii. Wielu pisarzy posługuje się teoriami Freunda. Jednym z nich jest wspomniany Siegfried Lenz z opowiadaniem „Ein Haus aus lauter Liebe“. W książce „Totem und Tabu” Freud opisuje relacje ojcowskie. Najbardziej znaną tezą tej książki jest morderstwo hordy braci na swoim ojcu. W opowiadaniu „Jäger des Spotts“ zbadam powiązania ze średniowieczną heroiczną pieśnią, jaką jest „Hildebrandslied” i znaleźć odpowiednie powiązania. „Hildebrandslied” to najwcześniejsze świadectwo poetyckiego tekstu w języku niemieckim. W obu tekstach chodzi o relację ojciec-syn. Bohaterowie, których będę opisywała mają różne cechy, ale problem ojcowskiej akceptacji i uznania dominuje w obu historiach.The problem of this bachelor's thesis is the analysis of conflicts between father and son in the stories "Ein Haus aus lauter Liebe" ("The House of Pure Love") and "Jäger des Spotts" ("Hunter mockery") by Siegfried Lenz. I chose this topic because in the literature family relations and interpersonal contacts are an inexhaustible source of research. In my work, I will try to prove whether the heavy childhood experiences and the missing father person influenced the work of Siegfried Lenz.The stories "Ein Haus aus lauter Liebe" and "Jäger des Spotts" come from the collection of stories "Geschichten aus dieser Zeit" ("Tales from these times"). Why does this book bear such a title? Because they are timeless stories. Described characters have the same problems as we do today. The stories that I will study describe the distorted relationship between father and son. The problem of parental relations is repeated in the life of every person, regardless of the age.There are many questions about the stories of Siegfried Lenz, which must be answered. Interpersonal relationships usually refer to psychology. Many writers use Freund's theories. One of them is the mentioned Siegfried Lenz with the short story "Ein Haus aus lauter Liebe". In the book "Totem und Tabu", Freud describes paternal relations. The most-known thesis of this book is the murder of a horde of brothers on his father. In the story "Jäger des Spotts" I will examine the links with the medieval heroic song, which is "Hildebrandslied" and find the appropriate connections. "Hildebrandslied" is the earliest testimony of a poetic text in German. Both texts are about the father-son relationship. The heroes I will describe have different features, but the problem of paternal acceptance and recognition dominates in both stories.DieProblematik dieser Bachelorarbeit ist die Konfliktanalyse zwischen Vater und Sohn in den Geschichten "Ein Haus aus lauter Liebe" und "Jäger des Spotts" von Siegfried Lenz. Ich wählte dieses Thema, weil in der Literatur Familienbeziehungen und zwischenmenschliche Kontakte eine unerschöpfliche Quelle der Forschung sind. In meiner Arbeit werde ich versuchen zu beweisen, ob die schweren Kindheitserfahrungen und der vermisste Vater die Arbeit von Siegfried Lenz beeinflusst haben.Die Geschichten "Ein Haus aus lauter Liebe" und "Jäger des Spotts" stammen aus der Erzählsammlung "Geschichten aus dieser Zeit". Warum trägt dieses Buch einen solchen Titel? Weil sie zeitlose Geschichten sind. Beschriebene Charaktere haben die gleichen Probleme wie heute. Die Geschichten, die ich durchforschen werde, beschreiben die verzerrte Beziehung zwischen Vater und Sohn. Das Problem der elterlichen Beziehungen wiederholt sich im Leben jedes Menschen, unabhängig vom Alter.Es gibt viele Fragen zu den Geschichten von Siegfried Lenz, die beantwortet werden müssen. Zwischenmenschliche Beziehungen beziehen sich normalerweise auf die Psychologie. Viele Autoren benutzen Freunds Theorien. Einer von ihnen ist der erwähnte Siegfried Lenz mit der Kurzgeschichte "Ein Haus aus lauter Liebe". In dem Buch "Totem und Tabu" beschreibt Freud väterliche Beziehungen. Die bekannteste These dieses Buches ist der Mord an einer Horde von Brüdern an seinem Vater. In der Geschichte "Jäger des Spotts" werde ich die Verbindungen zum mittelalterlichen Heldenlied, dem "Hildebrandslied", untersuchen und die entsprechenden Zusammenhänge finden. "Hildebrandslied" ist das früheste Zeugnis eines poetischen Textes auf Deutsch. Beide Texte handeln von der Vater-Sohn-Beziehung. Die Helden, die ich beschreiben werde, haben unterschiedliche Merkmale, aber das Problem der väterlichen Akzeptanz und Anerkennung dominiert in beiden Geschichten

Evidence of In Vivo Cross Talk between the Nitrogen-Related and Fructose-Related Branches of the Carbohydrate Phosphotransferase System of Pseudomonas putida▿

The genome of Pseudomonas putida KT2440 encodes only five recognizable proteins belonging to the phosphoenolpyruvate (PEP)-carbohydrate phosphotransferase system (PTS). Two of these PTS constituents (FruA and FruB) form a complete system for fructose intake. The other three products, encoded by ptsP (EINtr), ptsO (NPr), and ptsN (EIIANtr), comprise a branch of the system unrelated to sugar traffic but thought to have an influence on coordination of N and C metabolism. We used a genetic approach to clarify the course of high-energy phosphate through this reduced set of PTS proteins. To this end, we monitored the phosphorylation state in vivo of the EIIANtr enzyme in various genetic backgrounds and growth conditions. Our results show that the source of phosphate available to the system is PEP and that the primary flow of phosphate through the N/C-sensing PTS proceeds from PEP to EINtr to NPr to EIIANtr. We also found that in the presence of fructose, unlike in the presence of succinate, EIIANtr can be phosphorylated in a ptsP strain but not in a ptsP fruB double mutant. This result revealed that the fructose transport system has the ability to cross talk in vivo with the N-related PTS branch. The data reported here thus document an unexpected connection in vivo between the sugar-dependent and sugar-independent PTSs