Direct binding of phosphatidylglycerol at specific sites modulates desensitization of a ligand-gated ion channel

Pentameric ligand-gated ion channels (pLGICs) are essential determinants of synaptic transmission, and are modulated by specific lipids including anionic phospholipids. The exact modulatory effect of anionic phospholipids in pLGICs and the mechanism of this effect are not well understood. Using native mass spectrometry, coarse-grained molecular dynamics simulations and functional assays, we show that the anionic phospholipid, 1-palmitoyl-2-oleoyl phosphatidylglycerol (POPG), preferentially binds to and stabilizes the pLGIC, Erwinia ligand-gated ion channel (ELIC), and decreases ELIC desensitization. Mutations of five arginines located in the interfacial regions of the transmembrane domain (TMD) reduce POPG binding, and a subset of these mutations increase ELIC desensitization. In contrast, a mutation that decreases ELIC desensitization, increases POPG binding. The results support a mechanism by which POPG stabilizes the open state of ELIC relative to the desensitized state by direct binding at specific sites

Aerosol-assisted CVD of cadmium diselenoimidodiphosphinate and formation of a new iPr2N2P3+ ion supported by combined DFT and mass spectrometric studies

Aerosol-assisted chemical vapour deposition (AACVD) of Cd[(SePiPr2)2N]2 is shown to deposit cadmium selenide and/or cadmium phosphide on glass substrates, depending upon the growth conditions. The phase, structure, morphology and composition of the films were characterised by X-ray powder diffraction (XRD), scanning electron microscopy, energy dispersive X-ray analysis and X-ray photoelectron spectroscopy. The XRD indicated a hexagonal phase for cadmium selenide, whilst cadmium phosphide was monoclinic. Pyrolysis gas chromatography-mass spectrometry and density functional theory were used to deduce a breakdown mechanism for the deposition that favoured the formation of a new aromatic iPr2N2P3+ ion

The Long-Term Labor Market Effects of Parental Unemployment

I investigate the impact of parental unemployment on children’s educational attainment and long-run labor market outcomes in Austria. I find that parental unemployment shortly before an important educational decision by parents for their children lowers a child’s probability of holding a university degree by more than 5 percentage points. I do not find that income is affected at the beginning of a child’s labor market career along the distribution, but I find a gradual deterioration later on. A substantial share of these long-term losses can be explained by the lower parental investment decision. My results emphasize the intergenerational and long-lasting consequences of parental unemployment

The fatal consequences of grief

In this paper we investigate the effect of stress on the survival probability using a child's death as the triggering event. Employing a propensity score weighted Kaplan-Meier estimator, we are able to explore the associated time pattern of grief without imposing assumptions on the underlying duration process. We find a non-monotonic relationship between time and relative survival rates: decreasing for 13 years after the event and slowly reversing afterward. However, even 19 years after the event bereaved parents have significantly lower survival probabilities compared to the hypothetical case, that the event had not occurred. Investigating the main reason for this development, our results indicate that bereaved parents have a higher probability of dying from natural causes, especially circulatory diseases. Interestingly, our results reveal that bereavement has a stronger impact on fathers, while we find only modest evidence for mothers. This is a novel and surprising finding as males are in general regarded as more stress resilient than females. However, this research shows that this perception is not true

Untersuchung von ChMob2 und ChPxmp4 als Virulenzfaktoren von Colletotrichum higginsianum bei der Interaktion mit Arabidopsis thaliana

The hemibiotrophic fungus Colletotrichum higginsianum from the division of the ascomycetes causes the anthracnose disease on various brassicaceae like pak-choi. Under laboratory conditions, C. higginsianum is also able to establish a compatible interaction with the model plant Arabidopsis thaliana. The infection cycle of this pathogenic fungus is divided into two parts: During the biotrophic phase, host cuticle and epidermis get penetrated by the appressorium. Upon successful penetration, biotrophic primary hyphae, which are surrounded by host plasma membrane, grow into the invaded cell. After some time, thin secondary hyphae grow from primary hyphae and spread to neighboring tissue. This initiates the necrotrophic phase of infection, in which the host is actively killed and the fungus feeds on dead plant tissue. The aim of this study was to identify virulence factors of C. higginsianum and their function during its interaction with A. thaliana. For this reason, 75 C. higginsianum mutants with reduced pathogenicity were isolated in preliminary studies from a collection of random insertional T-DNA mutants. As a first step in the identification of virulence genes, the amount of T-DNA-Insertions and the insertion sites in the genomes of a selection of these mutants were determined. Two promising virulence mutants and their respective T-DNA-tagged genes were examined in detail. vir-88 forms appressoria with morphologic deformations, which are possibly caused by defects during the maintenance of cell polarity. Since only few of these appressoria are able to penetrate, vir-88 is less virulent against A. thaliana. Furthermore, vir-88 produces less and smaller conidia, which points to additional defects during conidiation. The genome of vir-88 contains a T-DNA-Insertion upstream of the ChMOB2 gene, which seems to be essential in C. higginsianum and encodes a kinase-activating protein widely spread among eukaryotes. All phenotypes of vir-88 could be complemented with ChMOB2. Thus, ChMOB2 represents a virulence factor so far unknown in phytopathogenic ascomycetes. It could be shown that ChMob2 binds to and mostly co-localizes with the NDR/LATS-Kinase ChCbk1. In order to determine the function of this complex, it was attempted to identify ChCbk1-regulated target proteins. The mRNA-binding protein ChSsd1 and especially the transcription factor ChAce2 are promising candidates because knockout mutants of these genes show phenotypes resembling that of vir-88. Moreover, the genome of C. higginsianum encodes two paralogs of ChMob2. While ChMob3 does not have an obvious function in C. higginsianum, ChMob1 is required for septation and full virulence. The genome of vir-56 contains a T-DNA-Insertion upstream of the ChPXMP4 gene. Although the phenotype of vir-56 was not linked to that gene, ChPXMP4 was determined to be a virulence factor in the C. higginsianum - A. thaliana interaction. Knockout mutants of ChPXMP4 form appressoria that rarely penetrate the host and produce only few primary and secondary hyphae. This phenotype is probably caused by a defect in peroxisomal function since Δpxmp4 mutants are unable to grow on fatty acids as carbon source and contain bigger but less peroxisomes. ChPxmp4 localizes to peroxisomes and is possibly needed for fission of these organelles. In addition to the investigation of virulence mutants, it was attempted to determine virulence factors by analysis of homologs of known pathogenicity-related genes from other systems. Using this approach, the potential secreted effector ChMc69 was identified. This protein possibly inhibits the recognition of C. higginsianum by the host and is required for efficient penetration by appressoria. Moreover, a collection of plasmid vectors was constructed which enables the expression of C. higginsianum genes as reporter fusions either ectopically or in their endogenous loci.Der hemibiotrophe Pilz Colletotrichum higginsianum gehört zur Abteilung der Schlauchpilze und ruft die Anthraknose-Krankheit auf verschiedenen Kreuzblütlern, wie z.B. Pak Choi, hervor. Unter Laborbedingungen ist C. higginsianum auch in der Lage, eine kompatible Interaktion mit der Modellpflanze Arabidopsis thaliana einzugehen. Der Infektionszyklus dieses Pilzes besteht aus zwei Teilen: In der biotrophen Phase der Infektion werden zunächst die pflanzliche Kutikula und Zellwand mit Hilfe von Appressorien als spezialisierte Penetrationsorgane durchdrungen. Nach erfolgreicher Penetration wachsen daraus von pflanzlicher Plasmamembran umgebene, biotrophe Primärhyphen. Anschließend bilden sich aus den Primärhyphen dünne, nekrotrophe Sekundärhyphen. Dies leitet den Übergang in die nekrotrophe Phase der Infektion ein, in der der Wirt aktiv abgetötet wird und der Pilz sich von totem Pflanzenmaterial ernährt. Das Ziel dieser Arbeit war die Identifikation von C. higginsianum Virulenzfaktoren und deren Funktion in der Interaktion mit A. thaliana. Dafür wurde in Vorarbeiten aus einer Bibliothek aus zufälligen T-DNA-Insertionsmutanten 75 C. higginsianum Mutanten mit reduzierter Pathogenität isoliert. Für eine Auswahl dieser Mutanten wurde in dieser Arbeit durch Bestimmung der Zahl an T-DNA-Insertionen und deren genomischer Insertionsorte ein erster Schritt zur Identifikation von Virulenzgenen getan. Zwei vielversprechende Pathogenitätsmutanten und deren potentiell von der T-DNA betroffene Gene wurden im Detail untersucht. vir-88 bildet Appressorien mit morphologischen Verformungen, die möglicherweise von Defekten bei der Aufrechterhaltung der Zellpolarität herrühren. Da nur wenige dieser Appressorien zur Penetration in der Lage sind, zeigt vir-88 reduzierte Pathogenität gegen A. thaliana. Daneben produziert vir-88 weniger und kleinere Konidien, was auf zusätzliche Defekte bei der Bildung von Konidien hindeutet. Das Genom von vir-88 enthält eine T-DNA-Insertion upstream des ChMOB2-Gens, welches in C. higginsianum essentiell zu sein scheint und für ein in vielen Eukaryonten vorkommendes kinaseaktivierendes Protein kodiert. Alle Phänotypen von vir-88 konnten durch Transformation mit ChMOB2 komplementiert werden, weswegen ChMOB2 einen in phytopathogenen Ascomyceten bisher unbekannten Virulenzfaktor darstellt. Es konnte experimentell bestätigt werden, dass ChMob2 an die NDR/LATS-Kinase ChCbk1 bindet und zumeist mit dieser co-lokalisiert. Um die Funktion dieses Komplexes zu bestimmen, wurde versucht, von ChCbk1 regulierte Zielproteine zu identifizieren. Das mRNA-bindende Protein ChSsd1 und besonders der Transkriptionsfaktor ChAce2 sind dafür vielversprechende Kandidaten, da Knockoutmutanten der jeweiligen Gene Phänotypen aufwiesen, die dem der vir-88 Mutante ähnelten. Des Weiteren kodiert das Genom von C. higginsianum für zwei Paraloge von ChMob2. Während für ChMob3 keine offensichtliche Funktion in C. higginsianum erkennbar ist, wird ChMob1 für die Zellteilung, für die Bildung von Septen und für volle Virulenz benötigt. Als zweite Mutante wurde vir-56 untersucht, welche eine T-DNA-Insertion upstream von ChPXMP4 trägt. Obwohl der Phänotyp von vir-56 nicht mit ChPXMP4 gekoppelt war, konnte dieses Gen als ein Virulenzfaktor in der C. higginsianum - A. thaliana-Interaktion bestimmt werden. Knockoutmutanten von ChPXMP4 bilden Appressorien, die den Wirt nur sehr selten penetrieren und deswegen kaum Primär- und Sekundärhyphen produzieren. Dieser Phänotyp wird vermutlich durch einen Defekt in der Funktion von Peroxisomen hervorgerufen, da Δpxmp4 Mutanten außerdem nicht in der Lage waren, auf Fettsäuren als Kohlenstoffquelle zu wachsen, und weniger, aber größere Peroxisomen enthalten. ChPxmp4 lokalisiert in Peroxisomen und wird möglicherweise für die Spaltung dieser Organellen benötigt. Zusätzlich zur Untersuchung von Virulenzmutanten wurde in dieser Arbeit versucht, Virulenzfaktoren durch Analyse von C. higginsianum Homologen bekannter pathogenitätsrelevanter Gene aus anderen Systemen zu identifizieren. Mithilfe dieses Ansatzes konnte der potentielle sekretierte Effektor ChMc69 ausgemacht werden, der möglicherweise die Erkennung von C. higginsianum durch den Wirt unterbindet und ohne den Appressorien deutlich seltener zur Penetration fähig sind. Außerdem wurde im Rahmen dieser Arbeit eine Sammlung an Plasmidvektoren konstruiert, die es ermöglicht C. higginsianum Gene als Reportergenfusionen sowohl ektopisch als auch in ihren endogenen Loki zu exprimieren

The fatal consequences of grief

In this paper we investigate the effect of stress on the survival probability using a child's death as the triggering event. Employing a propensity score weighted Kaplan-Meier estimator, we are able to explore the associated time pattern of grief without imposing assumptions on the underlying duration process. We find a non-monotonic relationship between time and relative survival rates: decreasing for 13 years after the event and slowly reversing afterward. However, even 19 years after the event bereaved parents have significantly lower survival probabilities compared to the hypothetical case, that the event had not occurred. Investigating the main reason for this development, our results indicate that bereaved parents have a higher probability of dying from natural causes, especially circulatory diseases. Interestingly, our results reveal that bereavement has a stronger impact on fathers, while we find only modest evidence for mothers. This is a novel and surprising finding as males are in general regarded as more stress resilient than females. However, this research shows that this perception is not true

Monopsony: Wages, wage bargaining and job requirements

Using linked vacancy-employer-employee data from Austria, we investigate how monopsony power affects firms' posting behavior and wage negotiations. Consistent with theoretical predictions, we find that firms with greater monopsony power post lower wages and offer fewer non-wage amenities, suggesting that wages and non-wage benefits are complementary. However, we find no evidence that monopsonistic firms demand higher levels of skill or education. Instead, our results indicate that they require more basic skills, particularly those related to routine tasks. On the workers' side, we find that employees hired in monopsonistic labor markets face significantly lower wages, both initially and in the long run. These lower wages are driven by both lower posted wages and reduced bargaining power, as well as reduced opportunities to climb the wage ladder later