Are ectomycorrhizal fungi alleviating or aggravating nitrogen limitation of tree growth in boreal forests?

•Symbioses between plant roots and mycorrhizal fungi are thought to enhance plant uptake of nutrients through a favourable exchange for photosynthates. Ectomycorrhizal fungi are considered to play this vital role for trees in nitrogen (N)-limited boreal forests. •We followed symbiotic carbon (C)–N exchange in a large-scale boreal pine forest experiment by tracing 13CO2 absorbed through tree photosynthesis and 15N injected into a soil layer in which ectomycorrhizal fungi dominate the microbial community. •We detected little 15N in tree canopies, but high levels in soil microbes and in mycorrhizal root tips, illustrating effective soil N immobilization, especially in late summer, when tree belowground C allocation was high. Additions of N fertilizer to the soil before labelling shifted the incorporation of 15N from soil microbes and root tips to tree foliage. •These results were tested in a model for C–N exchange between trees and mycorrhizal fungi, suggesting that ectomycorrhizal fungi transfer small fractions of absorbed N to trees under N-limited conditions, but larger fractions if more N is available. We suggest that greater allocation of C from trees to ectomycorrhizal fungi increases N retention in soil mycelium, driving boreal forests towards more severe N limitation at low N supply.

"Hochgeehrter, lieber Herr Professor Freud" (Radiogespräch, Sendung «Perspektiven», SRF2)

Sigmund Freud, der Begründer der Psychoanalyse, pflegte zeitlebens viele Freundschaften mit Fachkollegen. Aber kaum eine dauerte so lange wie jene mit dem Schweizer Pfarrer und Psychoanalytiker Oskar Pfister.

Gründungsgesten der Schweizer Theaterwissenschaft

Als sich 1927 die Gesellschaft für innerschweizerische Theaterkultur konstituierte, galt die Errichtung eines theaterwissenschaftlichen Institutes an einer schweizerischen Universität als eines der erklärten Ziele, welches erst 1992 mit der Gründung des Instituts für Theaterwissenschaft an der Universität Bern erreicht war. Der Beitrag befragt die von Oskar Eberle ab den 1920er Jahren formulierten Gründungsgesten auf ihre internationalen Bezugnahmen wie auch auf deren Funktionalisierung im nationalen Kontext.

The dog as a genetic model for immunoglobulin A (IgA) deficiency: identification of several breeds with low serum IgA concentrations

Immunoglobulin A (IgA) serves as the basis of the secretory immune system by protecting the lining of mucosal sites from pathogens. In both humans and dogs, IgA deficiency (IgAD) is associated with recurrent infections of mucosal sites and immune-mediated diseases. Low concentrations of serum IgA have previously been reported to occur in a number of dog breeds but no generally accepted cut-off value has been established for canine IgAD. The current study represents the largest screening to date of IgA in dogs in terms of both number of dogs (n = 1267) and number of breeds studied (n = 22). Serum IgA concentrations were quantified by using capture ELISA and were found to vary widely between breeds. We also found IgA to be positively correlated with age (p < 0.0001). Apart from the two breeds previously reported as predisposed to low IgA (Shar-Pei and German shepherd), we identified six additional breeds in which ≥10% of all tested dogs had very low (<0.07 g/l) IgA concentrations (Hovawart, Norwegian elkhound, Nova Scotia duck tolling retriever, Bullterrier, Golden retriever and Labrador retriever). In addition, we discovered low IgA concentrations to be significantly associated with canine atopic dermatitis (CAD, p < 0.0001) and pancreatic acinar atrophy (PAA, p = 0.04) in German shepherds.

Genome-Wide Analyses Suggest Mechanisms Involving Early B-Cell Development in Canine IgA Deficiency.

Immunoglobulin A deficiency (IgAD) is the most common primary immune deficiency disorder in both humans and dogs, characterized by recurrent mucosal tract infections and a predisposition for allergic and other immune mediated diseases. In several dog breeds, low IgA levels have been observed at a high frequency and with a clinical resemblance to human IgAD. In this study, we used genome-wide association studies (GWAS) to identify genomic regions associated with low IgA levels in dogs as a comparative model for human IgAD. We used a novel percentile groups-approach to establish breed-specific cut-offs and to perform analyses in a close to continuous manner. GWAS performed in four breeds prone to low IgA levels (German shepherd, Golden retriever, Labrador retriever and Shar-Pei) identified 35 genomic loci suggestively associated (p <0.0005) to IgA levels. In German shepherd, three genomic regions (candidate genes include KIRREL3 and SERPINA9) were genome-wide significantly associated (p <0.0002) with IgA levels. A ~20kb long haplotype on CFA28, significantly associated (p = 0.0005) to IgA levels in Shar-Pei, was positioned within the first intron of the gene SLIT1. Both KIRREL3 and SLIT1 are highly expressed in the central nervous system and in bone marrow and are potentially important during B-cell development. SERPINA9 expression is restricted to B-cells and peaks at the time-point when B-cells proliferate into antibody-producing plasma cells. The suggestively associated regions were enriched for genes in Gene Ontology gene sets involving inflammation and early immune cell development.

Diskurslinguistik im Spannungsfeld von Deskription und Kritik

Im vorliegenden Band geht es darum, den in der Linguistik früh etablierten Antagonismus zwischen Deskriptivismus und Kritik/Normativität/Präskriptivismus aus unterschiedlichen innerdisziplinären Blickwinkeln und Positionen zu reflektieren und zu hinterfragen. Ausgehend von der Beobachtung, dass Diskurse in den zur Diskussion stehenden Ansätzen einer linguistischen Diskursforschung semiotische Strukturen, Prozesse, Praktiken, Ereignisse oder Potentiale mit Wirklichkeit repräsentierender, wirklichkeitskonstitutiver und wirklichkeitsverändernder sowie aussagenregulativer Funktion sind, ist es das Ziel des Buches, die innerdisziplinär auseinanderlaufenden und (potentiell) konvergierenden Entwicklungen zur linguistischen Sprach-, Interaktions-, Wissens- und Machtanalyse vergleichend und gegebenenfalls auch integrativ aufeinander zu beziehen. Der vorliegende Band ist mithin als Forum für die Betrachtung und Darstellung von tatsächlichen und möglichen Gemeinsamkeiten und Unterschieden zwischen sogenannter „deskriptiver“ und sogenannter „kritischer“ Diskursanalyse konzipiert. Von Interesse sind in den Beiträgen unter anderem Fragen zum Wissenschaftsverständnis und Erkenntnisinteresse der jeweiligen Ansätze einer Diskursanalyse, zu ihrer möglichen normativen Fundierung, zur semiotischen Analyse der Multimodalität von Diskursen, zur sozialen Stratifizierung „gesellschaftlicher Redeweisen“, zu Sprachideologien und Sprachidealen, zum Verhältnis von Sprache, Diskurs und Handlung, zu diskursiv konstituierter Sozialsymbolik, zur diskursrelevanten Framestruktur von Wissen, zur Anwendungsperspektive von Diskursforschung und zu Fragen der praktischen Bedeutung diskursanalytisch gewonnener Erkenntnisse.