The Plastid Outer Envelope – A Highly Dynamic Interface between Plastid and Cytoplasm

Plastids are the defining organelles of all photosynthetic eukaryotes. They are the site of photosynthesis and of a large number of other essential metabolic pathways, such as fatty acid and amino acid biosyntheses, sulfur and nitrogen assimilation, and aromatic and terpenoid compound production, to mention only a few examples. The metabolism of plastids is heavily intertwined and connected with that of the surrounding cytosol, thus causing massive traffic of metabolic precursors, intermediates, and products. Two layers of biological membranes that are called the inner (IE) and the outer (OE) plastid envelope membranes bound the plastids of Archaeplastida. While the IE is generally accepted as the osmo-regulatory barrier between cytosol and stroma, the OE was considered to represent an unspecific molecular sieve, permeable for molecules of up to 10 kDa. However, after the discovery of small substrate specific pores in the OE, this view has come under scrutiny. In addition to controlling metabolic fluxes between plastid and cytosol, the OE is also crucial for protein import into the chloroplast. It contains the receptors and translocation channel of the TOC complex that is required for the canonical post-translational import of nuclear-encoded, plastid-targeted proteins. Further, the OE is a metabolically active compartment of the chloroplast, being involved in, e.g., fatty acid metabolism and membrane lipid production. Also, recent findings hint on the OE as a defense platform against several biotic and abiotic stress conditions, such as cold acclimation, freezing tolerance, and phosphate deprivation. Moreover, dynamic non-covalent interactions between the OE and the endomembrane system are thought to play important roles in lipid and non-canonical protein trafficking between plastid and endoplasmic reticulum. While proteomics and bioinformatics has provided us with comprehensive but still incomplete information on proteins localized in the plastid IE, the stroma, and the thylakoids, our knowledge of the protein composition of the plastid OE is far from complete. In this article, we report on the recent progress in discovering novel OE proteins to draw a conclusive picture of the OE. A “parts list” of the plastid OE will be presented, using data generated by proteomics of plastids isolated from various plant sources

The potential of a sustainable municipal waste management system for Santiago de Chile, including energy production from waste

Background: Due to a rapid urbanization process in the Metropolitan Region of Santiago de Chile (MRS), the amount of municipal solid waste (MSW) generated has increased considerably within the last years. MSW should be managed properly in order to achieve sustainable development. The purpose of this study is to analyze MSW management in MRS on the basis of three different explorative scenarios for the year 2030. Methods: The Integrative Sustainability Concept of the Helmholtz Association provided a conceptual framework for the study and was used to evaluate the scenarios. One important topic within the field of management of MSW in the year 2030 will be the contribution of waste treatment technologies to energy production, e.g., by the use of landfill gas and by separated collection of biowaste followed by anaerobic treatment. Results: The largest sustainability deficits in the scenarios are the small proportion of MSW being pre-treated before final disposal and the greenhouse gas (GHG) emissions associated with MSW disposal. MSW management technologies taken into consideration were mechanical biological treatment, energy recovery from MSW in anaerobic digestion plants with biogas production, the production of refuse-derived fuel and its use as a secondary fuel, as well as electricity generation from landfill gas. Energy generation from MSW in 2030 will be about 6% of electricity consumption in 2010. Conclusions: The three scenarios show some sustainability deficits. Even so, there are some improvements such as the reduction of GHG emissions and - even though marginal - energy supply for MRS from renewable energy sources

Determinanten der Kundenloyalität im Automobilsektor

Gegenwärtig sehen sich die PKW-Hersteller weltweit tiefgreifenden Strukturveränderungen in ihren Volumenmärkten gegenüber. Nach langjährigem stetigen Wachstum sinkt z.B. in West-Europa, USA und Japan erstmals die Nachfrage. Weiterhin lassen sich diese für die Automobilwirtschaft so wichtigen Absatzgebiete dadurch charakterisieren, daß die Marktvolumina von einer steigenden Zahl von Wettbewerbern umkämpft sind. Bedingt durch vergleichsweise niedrige Eintrittsbarrieren erscheint vor allem Westeuropa für die Umsetzung der Markterweiterungsstrategien südostasiatischer Automobilhersteller attraktiv. Darüber hinaus gefährdet der durch den Wertewandel induzierte Trend einer abnehmenden Bedeutung materieller Werte zudem den durch das Prestige eines Fahrzeugs erzielbaren immateriellen Zusatznutzen und erhöht damit vor allem in höherpreisigen Marktsegmenten die Preiselastizität der Konsumenten. Beim Handel führen diese Entwicklungen zu Preiskämpfen insbesondere im Intra-Brand-Wettbewerb, der in manchen Ländern durch Reimporte aus dem Ausland weiter verschärft wird. Berücksichtigt man außerdem die Verkaufs-, Lager- und Vorhaltekosten für immer differenziertere Modellpaletten, so kann es nicht verwundern, wenn gegenwärtig die durchschnittliche Umsatzrendite im deutschen Automobilhandel bei unter einem Prozent liegt. Im Aufbau einer intensiveren Beziehung mit dem Kunden sehen seit einiger Zeit viele Automobilhersteller und -händler eine Lösung der skizzierten Probleme. Als ökonomische Konsequenz erhoffen sich Hersteller und Handel von einer erhöhten Kundenloyalität eine Steigerung der Umsätze, eine erfolgreiche Preisdurchsetzung sowie niedrigere Kosten. In der betriebswirtschaftlichen Forschung und Praxis wird für die Bindung eines loyalen Kunden im Vergleich zur Neukundenakquisition übereinstimmend von lediglich etwa 20 Prozent der Kosten ausgegangen. Dieses Arbeitspapier ist auch in folgendem Paket enthalten: Automobil-Marketin

Comprehensive transcriptome analysis of the highly complex Pisum sativum genome using next generation sequencing

<p>Abstract</p> <p>Background</p> <p>The garden pea, <it>Pisum sativum</it>, is among the best-investigated legume plants and of significant agro-commercial relevance. <it>Pisum sativum </it>has a large and complex genome and accordingly few comprehensive genomic resources exist.</p> <p>Results</p> <p>We analyzed the pea transcriptome at the highest possible amount of accuracy by current technology. We used next generation sequencing with the Roche/454 platform and evaluated and compared a variety of approaches, including diverse tissue libraries, normalization, alternative sequencing technologies, saturation estimation and diverse assembly strategies. We generated libraries from flowers, leaves, cotyledons, epi- and hypocotyl, and etiolated and light treated etiolated seedlings, comprising a total of 450 megabases. Libraries were assembled into 324,428 unigenes in a first pass assembly.</p> <p>A second pass assembly reduced the amount to 81,449 unigenes but caused a significant number of chimeras. Analyses of the assemblies identified the assembly step as a major possibility for improvement. By recording frequencies of Arabidopsis orthologs hit by randomly drawn reads and fitting parameters of the saturation curve we concluded that sequencing was exhaustive. For leaf libraries we found normalization allows partial recovery of expression strength aside the desired effect of increased coverage. Based on theoretical and biological considerations we concluded that the sequence reads in the database tagged the vast majority of transcripts in the aerial tissues. A pathway representation analysis showed the merits of sampling multiple aerial tissues to increase the number of tagged genes. All results have been made available as a fully annotated database in fasta format.</p> <p>Conclusions</p> <p>We conclude that the approach taken resulted in a high quality - dataset which serves well as a first comprehensive reference set for the model legume pea. We suggest future deep sequencing transcriptome projects of species lacking a genomics backbone will need to concentrate mainly on resolving the issues of redundancy and paralogy during transcriptome assembly.</p

Total colonic aganglionosis : multicentre study of surgical treatment and patient-reported outcomes up to adulthood

Background: Surgery for total colonic aganglionosis (TCA) is designed to preserve continence and achieve satisfactory quality of life. This study evaluated a comprehensive group of clinical and social outcomes. Methods: An international multicentre study from eight Nordic hospitals involving examination of case records and a patient-reported questionnaire survey of all patients born with TCA between 1987 and 2006 was undertaken. Results: Of a total of 116 patients, five (4 center dot 3 per cent) had died and 102 were traced. Over a median follow-up of 12 (range 0 center dot 3-33) years, bowel continuity was established in 75 (73 center dot 5 per cent) at a median age of 11 (0 center dot 5-156) months. Mucosectomy with a short muscular cuff and straight ileoanal anastomosis (SIAA) (29 patients) or with aJpouch (JIAA) (26) were the most common reconstructions (55 of 72, 76 per cent). Major early postoperative complications requiring surgical intervention were observed in four (6 per cent) of the 72 patients. In 57 children aged over 4 years, long-term functional bowel symptoms after reconstruction included difficulties in holding back defaecation in 22 (39 per cent), more than one faecal accident per week in nine (16 per cent), increased frequency of defaecation in 51 (89 per cent), and social restrictions due to bowel symptoms in 35 (61 per cent). Enterocolitis occurred in 35 (47 per cent) of 72 patients. Supplementary enteral and/or parenteral nutrition was required by 51 (55 per cent) of 93 patients at any time during follow-up. Of 56 responders aged 2-20 years, true low BMI for age was found in 20 (36 per cent) and 13 (23 per cent) were short for age. Conclusion: Reconstruction for TCA was associated with persistent bowel symptoms, and enterocolitis remained common. Multidisciplinary follow-up, including continuity of care in adulthood, might improve care standards in patients with TCA.Peer reviewe

AXL and CAV-1 play a role for MTH1 inhibitor TH1579 sensitivity in cutaneous malignant melanoma

Cutaneous malignant melanoma (CMM) is the deadliest form of skin cancer and clinically challenging due to its propensity to develop therapy resistance. Reactive oxygen species (ROS) can induce DNA damage and play a significant role in CMM. MTH1 protein protects from ROS damage and is often overexpressed in different cancer types including CMM. Herein, we report that MTH1 inhibitor TH1579 induced ROS levels, increased DNA damage responses, caused mitotic arrest and suppressed CMM proliferation leading to cell death both in vitro and in an in vivo xenograft CMM zebrafish disease model. TH1579 was more potent in abrogating cell proliferation and inducing cell death in a heterogeneous co-culture setting when compared with CMM standard treatments, vemurafenib or trametinib, showing its broad anticancer activity. Silencing MTH1 alone exhibited similar cytotoxic effects with concomitant induction of mitotic arrest and ROS induction culminating in cell death in most CMM cell lines tested, further emphasizing the importance of MTH1 in CMM cells. Furthermore, overexpression of receptor tyrosine kinase AXL, previously demonstrated to contribute to BRAF inhibitor resistance, sensitized BRAF mutant and BRAF/NRAS wildtype CMM cells to TH1579. AXL overexpression culminated in increased ROS levels in CMM cells. Moreover, silencing of a protein that has shown opposing effects on cell proliferation, CAV-1, decreased sensitivity to TH1579 in a BRAF inhibitor resistant cell line. AXL-MTH1 and CAV-1-MTH1 mRNA expressions were correlated as seen in CMM clinical samples. Finally, TH1579 in combination with BRAF inhibitor exhibited a more potent cell killing effect in BRAF mutant cells both in vitro and in vivo. In summary, we show that TH1579-mediated efficacy is independent of BRAF/NRAS mutational status but dependent on the expression of AXL and CAV-1

Glioblastoma and glioblastoma stem cells are dependent on functional MTH1

Glioblastoma multiforme (GBM) is an aggressive form of brain cancer with poor prognosis. Cancer cells are characterized by a specific redox environment that adjusts metabolism to its specific needs and allows the tumor to grow and metastasize. As a consequence, cancer cells and especially GBM cells suffer from elevated oxidative pressure which requires antioxidant-defense and other sanitation enzymes to be upregulated. MTH1, which degrades oxidized nucleotides, is one of these defense enzymes and represents a promising cancer target. We found MTH1 expression levels elevated and correlated with GBM aggressiveness and discovered that siRNA knock-down or inhibition of MTH1 with small molecules efficiently reduced viability of patient-derived GBM cultures. The effect of MTH1 loss on GBM viability was likely mediated through incorporation of oxidized nucleotides and subsequent DNA damage. We revealed that MTH1 inhibition targets GBM independent of aggressiveness as well as potently kills putative GBM stem cells in vitro. We used an orthotopic zebrafish model to confirm our results in vivo and light-sheet microscopy to follow the effect of MTH1 inhibition in GBM in real time. In conclusion, MTH1 represents a promising target for GBM therapy and MTH1 inhibitors may also be effective in patients that suffer from recurring disease