How Plants Sense Wounds: Damaged-Self Recognition Is Based on Plant-Derived Elicitors and Induces Octadecanoid Signaling

Background: Animal-derived elicitors can be used by plants to detect herbivory but they function only in specific insect– plant interactions. How can plants generally perceive damage caused by herbivores? Damaged-self recognition occurs when plants perceive molecular signals of damage: degraded plant molecules or molecules localized outside their original compartment. Methodology/Principal Findings: Flame wounding or applying leaf extract or solutions of sucrose or ATP to slightly wounded lima bean (Phaseolus lunatus) leaves induced the secretion of extrafloral nectar, an indirect defense mechanism. Chemically related molecules that would not be released in high concentrations from damaged plant cells (glucose, fructose, salt, and sorbitol) did not elicit a detectable response, excluding osmotic shock as an alternative explanation. Treatments inducing extrafloral nectar secretion also enhanced endogenous concentrations of the defense hormone jasmonic acid (JA). Endogenous JA was also induced by mechanically damaging leaves of lima bean, Arabidopsis, maize, strawberry, sesame and tomato. In lima bean, tomato and sesame, the application of leaf extract further increased endogenous JA content, indicating that damaged-self recognition is taxonomically widely distributed. Transcriptomic patterns obtained with untargeted 454 pyrosequencing of lima bean in response to flame wounding or the application of leaf extract or JA were highly similar to each other, but differed from the response to mere mechanical damage. W

X-Ray Spectroscopy of Stars

(abridged) Non-degenerate stars of essentially all spectral classes are soft X-ray sources. Low-mass stars on the cooler part of the main sequence and their pre-main sequence predecessors define the dominant stellar population in the galaxy by number. Their X-ray spectra are reminiscent, in the broadest sense, of X-ray spectra from the solar corona. X-ray emission from cool stars is indeed ascribed to magnetically trapped hot gas analogous to the solar coronal plasma. Coronal structure, its thermal stratification and geometric extent can be interpreted based on various spectral diagnostics. New features have been identified in pre-main sequence stars; some of these may be related to accretion shocks on the stellar surface, fluorescence on circumstellar disks due to X-ray irradiation, or shock heating in stellar outflows. Massive, hot stars clearly dominate the interaction with the galactic interstellar medium: they are the main sources of ionizing radiation, mechanical energy and chemical enrichment in galaxies. High-energy emission permits to probe some of the most important processes at work in these stars, and put constraints on their most peculiar feature: the stellar wind. Here, we review recent advances in our understanding of cool and hot stars through the study of X-ray spectra, in particular high-resolution spectra now available from XMM-Newton and Chandra. We address issues related to coronal structure, flares, the composition of coronal plasma, X-ray production in accretion streams and outflows, X-rays from single OB-type stars, massive binaries, magnetic hot objects and evolved WR stars.Comment: accepted for Astron. Astrophys. Rev., 98 journal pages, 30 figures (partly multiple); some corrections made after proof stag

Changes in Gene Expression and Cellular Architecture in an Ovarian Cancer Progression Model

BACKGROUND: Ovarian cancer is the fifth leading cause of cancer deaths among women. Early stage disease often remains undetected due the lack of symptoms and reliable biomarkers. The identification of early genetic changes could provide insights into novel signaling pathways that may be exploited for early detection and treatment. METHODOLOGY/PRINCIPAL FINDINGS: Mouse ovarian surface epithelial (MOSE) cells were used to identify stage-dependent changes in gene expression levels and signal transduction pathways by mouse whole genome microarray analyses and gene ontology. These cells have undergone spontaneous transformation in cell culture and transitioned from non-tumorigenic to intermediate and aggressive, malignant phenotypes. Significantly changed genes were overrepresented in a number of pathways, most notably the cytoskeleton functional category. Concurrent with gene expression changes, the cytoskeletal architecture became progressively disorganized, resulting in aberrant expression or subcellular distribution of key cytoskeletal regulatory proteins (focal adhesion kinase, α-actinin, and vinculin). The cytoskeletal disorganization was accompanied by altered patterns of serine and tyrosine phosphorylation as well as changed expression and subcellular localization of integral signaling intermediates APC and PKCβII. CONCLUSIONS/SIGNIFICANCE: Our studies have identified genes that are aberrantly expressed during MOSE cell neoplastic progression. We show that early stage dysregulation of actin microfilaments is followed by progressive disorganization of microtubules and intermediate filaments at later stages. These stage-specific, step-wise changes provide further insights into the time and spatial sequence of events that lead to the fully transformed state since these changes are also observed in aggressive human ovarian cancer cell lines independent of their histological type. Moreover, our studies support a link between aberrant cytoskeleton organization and regulation of important downstream signaling events that may be involved in cancer progression. Thus, our MOSE-derived cell model represents a unique model for in depth mechanistic studies of ovarian cancer progression

The desmosome and pemphigus

Desmosomes are patch-like intercellular adhering junctions (“maculae adherentes”), which, in concert with the related adherens junctions, provide the mechanical strength to intercellular adhesion. Therefore, it is not surprising that desmosomes are abundant in tissues subjected to significant mechanical stress such as stratified epithelia and myocardium. Desmosomal adhesion is based on the Ca2+-dependent, homo- and heterophilic transinteraction of cadherin-type adhesion molecules. Desmosomal cadherins are anchored to the intermediate filament cytoskeleton by adaptor proteins of the armadillo and plakin families. Desmosomes are dynamic structures subjected to regulation and are therefore targets of signalling pathways, which control their molecular composition and adhesive properties. Moreover, evidence is emerging that desmosomal components themselves take part in outside-in signalling under physiologic and pathologic conditions. Disturbed desmosomal adhesion contributes to the pathogenesis of a number of diseases such as pemphigus, which is caused by autoantibodies against desmosomal cadherins. Beside pemphigus, desmosome-associated diseases are caused by other mechanisms such as genetic defects or bacterial toxins. Because most of these diseases affect the skin, desmosomes are interesting not only for cell biologists who are inspired by their complex structure and molecular composition, but also for clinical physicians who are confronted with patients suffering from severe blistering skin diseases such as pemphigus. To develop disease-specific therapeutic approaches, more insights into the molecular composition and regulation of desmosomes are required

The role of leadership in salespeople’s price negotiation behavior

Salespeople assume a key role in defending firms’ price levels in price negotiations with customers. The degree to which salespeople defend prices should critically depend upon their leaders’ influence. However, the influence of leadership on salespeople’s price defense behavior is barely understood, conceptually or empirically. Therefore, building on social learning theory, the authors propose that salespeople might adopt their leaders’ price defense behavior given a transformational leadership style. Furthermore, drawing on the contingency leadership perspective, the authors argue that this adoption fundamentally depends on three variables deduced from the motivation–ability–opportunity (MAO) framework, that is, salespeople’s learning motivation, negotiation efficacy, and perceived customer lenience. Results of a multi-level model using data from 92 salespeople and 264 salesperson–customer interactions confirm these predictions. The first to explore contingencies of salespeople’s adoption of their transformational leaders’ price negotiation behaviors, this study extends marketing theory and provides actionable guidance to practitioners

The human keratins: biology and pathology

The keratins are the typical intermediate filament proteins of epithelia, showing an outstanding degree of molecular diversity. Heteropolymeric filaments are formed by pairing of type I and type II molecules. In humans 54 functional keratin genes exist. They are expressed in highly specific patterns related to the epithelial type and stage of cellular differentiation. About half of all keratins—including numerous keratins characterized only recently—are restricted to the various compartments of hair follicles. As part of the epithelial cytoskeleton, keratins are important for the mechanical stability and integrity of epithelial cells and tissues. Moreover, some keratins also have regulatory functions and are involved in intracellular signaling pathways, e.g. protection from stress, wound healing, and apoptosis. Applying the new consensus nomenclature, this article summarizes, for all human keratins, their cell type and tissue distribution and their functional significance in relation to transgenic mouse models and human hereditary keratin diseases. Furthermore, since keratins also exhibit characteristic expression patterns in human tumors, several of them (notably K5, K7, K8/K18, K19, and K20) have great importance in immunohistochemical tumor diagnosis of carcinomas, in particular of unclear metastases and in precise classification and subtyping. Future research might open further fields of clinical application for this remarkable protein family

Bedeutung der intraoperativen Parathormonbestimmung für Reoperationen wegen Hyperparathyreoidismus

Die vorliegende Promotionsarbeit untersuchte unterschiedliche Methoden der Lokalisationsdiagnostik sowie die Einsatzmöglichkeiten der intraoperativen Parathormonschnellmessung bei Reoperationen aufgrund eines Hyperparathyreoidismus. Eingeschlossen wurden 20 konsekutiv operierte Patienten der Klinik für Viszeral- Thorax- und Gefäßchirurgie der Philipps Universität Marburg. Bei 11 Patienten war bisher eine Halsexploration erfolgt, neun Patienten waren wenigstens zwei Mal voroperiert. Je 10 primäre und sekundäre Erkrankungen lagen vor. Präoperativ wurde bei allen Patienten ein standardisierter Ablauf an Lokalisationsuntersuchungen einschließlich MRT, Technetium 99m SestaMIBI Szintigraphie, Sonographie des Halses und selektiver Venenblutentnahme der tiefen Halsvenen über eine Punktion der V. Femoralis durchgeführt. Die primären Fragestellungen dieser prospektiv angelegten Beobachtungsstudie waren: 1) Kann der intraoperative Parathormonschnelltest als Erfolgskontrolle der Operation, im Sinne eines biochemischen Schnellschnittes, eingesetzt werden und wie groß ist dessen Aussagekraft für die postoperative Normokalzämie? 2) Kann die intraoperative selektive Venenblutentnahme unter Verwendung eines PTH Schnelltests die präoperative selektive Venenblutentnahme ersetzen? 3) Wie Aussagekräftig ist die MRT Untersuchung verglichen mit der SestaMIBI Szintigraphie in einer Bevölkerung mit endemischen Schilddrüsenerkrankungen? 18 von 20 Patienten konnten mindestens 6 Monate postoperativ nachuntersucht werden. 13 Patienten waren normokalzäm, bei 5 Patienten lag eine Hyperkalzämie vor. Bei 15 aller 18 nachuntersuchten Patienten wurde der Zustand postoperativer Normo- oder Hyperkalzämie durch die intraoperative Parathormonmessung zutreffend vorhergesagt. Bei vier Patienten war die intraoperative Parathormonschnellmessung relevant für den Verlauf der Operation. In diesen vier Fällen wurde die Operation nach Exzision einer erkrankten Nebenschilddrüse aufgrund des intraoperativen iPTH Schnelltestes fortgesetzt und es wurden weitere erkrankte Nebenschilddrüsen gefunden. Die intraoperative Parathormonschnellmessung erwies sich daher als geeignetes Instrument zur Prognose einer postoperativen Normo- oder Hyperkalzämie und als geeignetes Hilfsmittel für die intraoperative Entscheidung eine Halsexploration fortzusetzen oder zu beenden. Die Technetium 99m SestaMIBI Szintigraphie wies eine Spezifität und eine positive Prädiktion von 100% auf. Da sie zusätzlich als einzige Untersuchungsmethode in der Lage war alle im Thymus oder Mediastinum gelegenen erkrankten Nebenschilddrüsen darzustellen stellte sie, mit einer Treffsicherheit von 79 %, die rationalste Eingangsuntersuchung vor einem Reeingriff aufgrund eines Hyperparathyreoidismus dar. In der Reihenfolge ihrer Treffsicherheit waren MRT (70 %) und Sonographie (69 %) Lokalisationsmethoden der zweiten Reihe. Sie eigneten sich lediglich zur Abklärung unklarer Befunde. Bei erkrankten Nebenschilddrüsen im Thymus oder Mediastinum, war die MRT der Sonographie überlegen, da durch sie noch vier von sechs erkrankte Nebenschilddrüsen intrathymal oder mediastinal dargestellt wurden. Durch die Sonographie gelang dies in keinem Fall. Gemessen an der Invasivität der Maßnahme und den erzielten Ergebnissen war die präoperative selektive Venenblutentnahme die am wenigsten geeignete Methode der Lokalisationsdiagnostik. Die intraoperative selektive Venenblutentnahme aus der V. jugularis interna bds. war der präoperativen deutlich überlegen (Treffsicherheit 89,6 % vs 65,4 %