Prognose künftiger Problemunkräuter im Maisanbau durch Artverbreitungsmodellierung

Die starke Zunahme des Maisanbaus in den letzten Jahren und Veränderungen in der Anbautechnik haben die Selektion typischer Maisunkräuter gefördert, die auch in besonderem Maße von den Folgen des Klimawandels profitieren könnten. Für die Pflanzenproduktion ist es von hohem Interesse, zukünftige Probleme mit Unkräutern abzuschätzen. Im Projekt KLIFF wurden darum neben experimentellen Arbeiten auch Artverbreitungsmodellierungen für das Gebiet von Niedersachsen durchgeführt. Für die vorliegende Studie wurden für neun Unkrautarten, die in verschiedenen Ländern Europas große Bedeutung im Maisanbau haben und weitverbreitet auftreten, die ökologische Nische und die Schadensnische ermittelt. Die ökologische Nische beschreibt die Umweltbedingungen, die günstig für das dauerhafte Vorkommen einer Art sind, die „Schadensnische“ jene Umweltbedingungen, unter denen eine Art darüber hinaus Schaden in landwirtschaftlichen Kulturen hervorruft. Dazu wurden Vorkommensdaten aus verschiedenen Vegetationsdatenbanken mit hochaufgelösten Klima-, Boden- und Landnutzungsdaten kombiniert. Durch die Projektion der Modelle auf simulierte Klimawerte für die Zeit 2070 - 2100 wurden Effekte des Klimawandels abgeschätzt.Die Ergebnisse zeigen, dass in Niedersachsen bereits heute fast flächendeckend günstige Bedingungen für typische Maisunkräuter herrschen, aber nur einzelne Arten weitverbreitet hohe Bedeutung im Maisanbau besitzen (Echinochloa crus-galli, Chenopodium album, Polygonum convolvulus). Die Ergebnisse decken sich sehr gut mit Daten eines früheren Maisunkraut-Monitorings. Die Reaktion auf die veränderten Klimabedingungen zum Ende dieses Jahrhunderts ist artspezifisch sehr unterschiedlich. Einige Arten reagieren im potentiellen Vorkommen neutral (E. crus-galli), andere mit großflächigen Zugewinnen (Polygonum persicaria) oder Verlusten (Viola arvensis) geeigneter Habitate. Alle Arten, die heute bereits hohes Schadpotential aufweisen, behalten dieses; weitere Arten gewinnen regional Schadenspotential (Calystegia sepium, Setara viridis).Stichwörter: Klimawandel, MaxEnt, Niedersachsen, potentielle Verbreitung, ökologische Nische, Schadensnische, Echinochloa crus-galli, Chenopodium albumPredicting weed problems in maize cropping by species distribution modellingAbstractIncreasing maize cultivation and changed cropping practices promote the selection of typical maize weeds that may also profit strongly from climate change. Predicting potential weed problems is of high interest for plant production. Within the project KLIFF, experiments were combined with species distribution modelling for this task in the region of Lower Saxony, Germany. For our study, we modelled ecological and damage niches of nine weed species that are significant and wide spread in maize cropping in a number of European countries. Species distribution models describe the ecological niche of a species, these are the environmental conditions under which a species can maintain a vital population. It is also possible to estimate a damage niche, i.e. the conditions under which a species causes damage in agricultural crops. For this, we combined occurrence data of European national data bases with high resolution climate, soil and land use data. Models were also projected to simulated climate conditions for the time horizon 2070 - 2100 in order to estimate climate change effects.Modelling results indicate favourable conditions for typical maize weed occurrence virtually all over the study region, but only a few species are important in maize cropping. This is in good accordance with the findings of an earlier maize weed monitoring. Reaction to changing climate conditions is species-specific, for some species neutral (E. crus-galli), other species may gain (Polygonum persicaria) or loose (Viola arvensis) large areas of suitable habitats. All species with damage potential under present conditions will remain important in maize cropping, some more species will gain regional importance (Calystegia sepium, Setara viridis).Keywords: Chenopodium album, climate change, damage niche, Echinochloa crus-galli, ecological niche, Lower Saxony, MaxEnt, potential distributio

Klimafolgenforschung zu Ackerunkräutern – Daten, Methoden und Anwendungen auf verschiedenen Skalen

Eine große Anzahl an Einzeluntersuchungen hat sich in den vergangenen Jahren mit unterschiedlichen Aspekten der Folgen des Klimawandels für Biologie und Schadpotential von Ackerunkräutern befasst. Allerdings finden sich wenige Beispiele, die für einen definierten geographischen Raum und für einzelne Unkrautarten oder Anbausysteme ein umfassendes Bild liefern. Im Rahmen des Projektverbunds zur Klimafolgenforschung in Niedersachsen (KLIFF) wurde ein Forschungsansatz erprobt, der mehrere Skalenebenen übergreift und unterschiedliche Methoden verbindet. Dieser Ansatz sollte eine Möglichkeit liefern, die Folgen veränderter Klimabedingungen für Verbreitung und Leistungsfähigkeit einzelner Unkrautarten umfassend und mit möglichst hoher Vorhersagegenauigkeit abzuschätzen. Die Arten Abutilon theophrasti, Amaranthus retroflexus, Echinochloa crus-galli, Datura stramonium, Iva xanthiifolia und Setaria viridis wurden anhand eines solchen Vorgehens untersucht. Hierzu wurde eine korrelative Artverbreitungsmodellierung (regionale Skalenebene) mit kontrollierten Gefäßversuchen zu vegetativer und generativer Leistungsfähigkeit der Arten unter den für das Ende des Jahrhunderts für Niedersachsen erwarteten Klimabedingungen (lokale Skalenebene) verbunden. Bei der Zusammenführung der Daten zeigte sich, dass die Ergebnisse von der Modellierung und den empirischen Experimenten im Wesentlichen gut übereinstimmen. Für A. retroflexus, D. stramonium, E. crus-galli und S. viridis wiesen die Ergebnisse beider Untersuchungsmethoden auf eine neutrale bis positive Wirkung zukünftiger Klimabedingungen hin, für I. xanthiifolia hingegen auf eine negative Wirkung. Lediglich für A. theophrasti ließen sich die Ergebnisse von der Artverbreitungsmodellierung und den Gefäßversuchen nicht vollständig zur Deckung bringen. Insgesamt lassen unsere Ergebnisse die Einschätzung zu, dass der Ansatz, die Folgen von Klimawandel auf Ackerunkräuter mit einer mehrere Methoden und Skalenebenen verbindenden Herangehensweise zu untersuchen, zahlreiche Stärken aufweist. Diese Vorgehensweise erlaubt es, für eine definierte Untersuchungsregion unterschiedliche Datensätze zu einem detaillierten Gesamtergebnis aneinanderzupassen, und kann aus diesem Grunde, ggf. um weitere Aspekte erweitert, für die Untersuchung regionaler Klimawandelfolgen für Ackerunkräuter empfohlen werden.Stichwörter: Bioklimatische Nische, Habitateignung, korrelative Artverbreitungsmodellierung, regionales Klimamodell, tatsächliche VerbreitungClimate change impact research on arable weeds – data, methods and applications at various scale levelsAbstractIn the past years, a large number of studies have examined various aspects of possible consequences of climate change for the biology and damage potential of arable weeds. However, there are merely a few examples that have comprehensively investigated individual weed species or arable crop systems within a clearly delimited geographical area. In the frame of the research co-operation KLIFF (Climate change impact and adaptation research for Lower Saxony), we tested an approach that combines a number of methods to span several scale levels and types of environmental factors, which was intended to provide as accurate as possible an estimate of the potential distribution and performance of individual arable weed species under the predicted future climate conditions. This approach was put to practice for the species Abutilon theophrasti, Amaranthus retroflexus, Echinochloa crus-galli, Datura stramonium, Iva xanthiifolia and Setaria viridis. We combined projections of the potential future distribution of the individual weed species based on a correlative distribution modelling approach (regional scale level) with pot experiments (local scale level) on the vegetative and generative performance of these species under climatic conditions predicted for the end of the current century for Lower Saxony. A synopsis revealed that the results obtained from the different approaches corresponded to a large extent. For A. retroflexus, D. stramonium, E. crus-galli, and S. viridis, both approaches indicated a neutral or positive effect of the predicted future climate on their potential distribution and performance, whereas the opposite was found for I. xanthiifolia. Merely for A. theophrasti, results of the two methods did not fully concur. Altogether, our results highlight that investigating climate change impact on weeds by combining several methods to span several scale levels allows fitting various data sets to a comprehensive picture for a delimited region. It has a number of strengths which may be augmented by the inclusion of further aspects. Therefore, this approach can be recommended for research of the regional impacts of climate change on arable weeds.Keywords: Bioclimatic niche, correlative distribution modelling, habitat suitability, regional climate model, realized distributio

Kinome and mRNA expression profiling of high-grade osteosarcoma cell lines implies Akt signaling as possible target for therapy

Background: High-grade osteosarcoma is a primary malignant bone tumor mostly occurring in adolescents and young adults, with a second peak at middle age. Overall survival is approximately 60%, and has not significantly increased since the introduction of neoadjuvant chemotherapy in the 1970s. The genomic profile of high-grade osteosarcoma is complex and heterogeneous. Integration of different types of genome-wide data may be advantageous in extracting relevant information from the large number of aberrations detected in this tumor. Methods: We analyzed genome-wide gene expression data of osteosarcoma cell lines and integrated these data with a kinome screen. Data were analyzed in statistical language R, using LIMMA for detection of differential expression/phosphorylation. We subsequently used Ingenuity Pathways Analysis to determine deregulated pathways in both data types. Results: Gene set enrichment indicated that pathways important in genomic stability are highly deregulated in these tumors, with many genes showing upregulation, which could be used as a prognostic marker, and with kinases phosphorylating peptides in these pathways. Akt and AMPK signaling were identified as active and inactive, respectively. As these pathways have an opposite role on mTORC1 signaling, we set out to inhibit Akt kinases with the allosteric Akt inhibitor MK-2206. This resulted in inhibition of proliferation of osteosarcoma cell lines U-2 OS and HOS, but not of 143B, which harbors a KRAS oncogenic transformation. Conclusions: We identified both overexpression and hyperphosphorylation in pathways playing a role in genomic stability. Kinome profiling identified active Akt signaling, which could inhibit proliferation in 2/3 osteosarcoma cell lines. Inhibition of PI3K/Akt/mTORC1 signaling may be effective in osteosarcoma, but further studies are required to determine whether this pathway is active in a substantial subgroup of this heterogeneous tumor

Site-specific chromatin immunoprecipitation: a selective method to individually analyze neighboring transcription factor binding sites in vivo

<p>Abstract</p> <p>Background</p> <p>Transcription factors (TFs) and their binding sites (TFBSs) play a central role in the regulation of gene expression. It is therefore vital to know how the allocation pattern of TFBSs affects the functioning of any particular gene in vivo. A widely used method to analyze TFBSs in vivo is the chromatin immunoprecipitation (ChIP). However, this method in its present state does not enable the individual investigation of densely arranged TFBSs due to the underlying unspecific DNA fragmentation technique. This study describes a site-specific ChIP which aggregates the benefits of both EMSA and in vivo footprinting in only one assay, thereby allowing the individual detection and analysis of single binding motifs.</p> <p>Findings</p> <p>The standard ChIP protocol was modified by replacing the conventional DNA fragmentation, i. e. via sonication or undirected enzymatic digestion (by MNase), through a sequence specific enzymatic digestion step. This alteration enables the specific immunoprecipitation and individual examination of occupied sites, even in a complex system of adjacent binding motifs in vivo. Immunoprecipitated chromatin was analyzed by PCR using two primer sets - one for the specific detection of precipitated TFBSs and one for the validation of completeness of the enzyme digestion step. The method was established exemplary for Sp1 TFBSs within the <it>egfr </it>promoter region. Using this site-specific ChIP, we were able to confirm four previously described Sp1 binding sites within <it>egfr </it>promoter region to be occupied by Sp1 in vivo. Despite the dense arrangement of the Sp1 TFBSs the improved ChIP method was able to individually examine the allocation of all adjacent Sp1 TFBS at once. The broad applicability of this site-specific ChIP could be demonstrated by analyzing these SP1 motifs in both osteosarcoma cells and kidney carcinoma tissue.</p> <p>Conclusions</p> <p>The ChIP technology is a powerful tool for investigating transcription factors in vivo, especially in cancer biology. The established site-specific enzyme digestion enables a reliable and individual detection option for densely arranged binding motifs in vivo not provided by e.g. EMSA or in vivo footprinting. Given the important function of transcription factors in neoplastic mechanism, our method enables a broad diversity of application options for clinical studies.</p

Caveolin-1 expression in benign and malignant lesions of the breast

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Waste Heat Recovery for Fuel Cell Electric Vehicle with Thermochemical Energy Storage

In this paper, different waste heat recovery concepts for a high temperature fuel cell range extender vehicle developed by the DLR Institute of Vehicle Concepts will be presented. These concepts use thermochemical heat storages to recover thermal energy from the powertrain waste heat and to re-use it for heating purpose before or during the drive. The focus will be on metal hydride storages, which have a higher specific energy density than the phase change energy storages and will thus be more advantageous for vehicle application. In order to investigate the developed waste heat recovery concepts in the entire vehicle, appropriate simulation models will be created in the simulation environment Modelica/Dymola, then integrated into an overall vehicle simulation model. It is found that the integration of the thermochemical heat storages into the fuel cell thermal management system leads to increase the range by up to 17 %

Chromosome 16q loss– a genetic key to the understanding of breast carcinogenesis

In the last decade the concepts of breast cancer dedifferentiation and progression have undergone a significant and substantial change. In the past it was widely believed that the detailed associations between genetic and morphological changes defined in the Vogelstein model of colorectal cancer pathogenesis could be transferred to breast carcinogenesis. A multitude of studies seemed to verify this a priori hypothesis. However, with the introduction of global screening techniques, predominantly at the DNA level, it became obvious that this linear model might be oversimplified for breast cancer. It is now widely accepted that losses of chromosomal 16q characterize in-situ and invasive breast cancer tumours with predominantly low tumour grade and estrogen receptor (ER) positivity (luminal breast cancers). In contrast, high grade breast cancers of the HER2, the basal or the non expressor phenotype with 16q-losses are rarely seen and in consequence a concept of multiple, parallel pathways with defined precursor lesions emerged. As a consequence, it became obvious that the hunt for oncogenes/tumour suppressor genes in invasive breast cancer is pathway specific. Whereas high grade breast cancers have been relatively well characterized by several recurrent changes in oncogenes/tumour suppressor genes located on various chromosomal regions (e.g. egfr, p53, HER2), the characterization of a 16q-specific tumour suppressor gene in ER-positive breast cancer is still a tremendous challenge. This review will focus on the role of 16q in breast cancer and aims to give insights into actual research efforts, e.g. alternative explanations in order to unravel the central role of 16q in breast cancer

Thermomanagement and cabin climatization in electric vehicles using a hydrogen based A/C-unit

In this paper a hydrogen-based air-conditioning unit, which can also function as range extender for electric vehicles, is studied. This hydrogen A/C-unit utilizes the endothermic reaction of hydrogen desorption from metal hydrides to generate a cooling effect. Within DLR’s Next Generation Car project a prototype system was developed and characterized on a test bench. This system represents a world’s first proof of concept, where two metal hydride reactors are coupled to a fuel cell to establish a process which provides cooling power without any electrical power input. The measured cooling power is directly coupled to the hydrogen mass flow taken from the reactors, thus being indirectly linked to the fuel cells electrical power output. A maximal heat flow of 0.72 kW was detected at 5 kW electric fuel cell power. The paper concludes with the discussion of an appropriate vehicle integration concept for this innovative technology