Molecular diversity and ecology of microbial plankton

The history of microbial evolution in the oceans is probably as old as the history of life itself. In contrast to terrestrial ecosystems, microorganisms are the main form of biomass in the oceans, and form some of the largest populations on the planet. Theory predicts that selection should act more efficiently in large populations. But whether microbial plankton populations harbour organisms that are models of adaptive sophistication remains to be seen. Genome sequence data are piling up, but most of the key microbial plankton clades have no cultivated representatives, and information about their ecological activities is sparse.     

A refined test for X-ray induced dominant lethals inDrosophila

Zusammenfassung Die nach Röntgenbestrahlung frisch abgelegter besamterDrosophila-Eier registrierbare Letalität kann nach verschiedenen Letalsyndromen aufgegliedert werden. Zur Auswertung stehen Computerprogramme zur Verfügung. Spezielle Tests zeigten, dass mit der beschriebenen Zuchtanordnung bestrahlte und unbestrahlte Populationen, von denen 25–30 Puppen (bzw. Fliegen) pro Zuchtglas überleben, ohne Beeinflussung durch ungünstige Zuchtbedingungen auf dominante Letalfaktoren geprüft werden können.

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Work supported by Schweizerischer Nationalfonds zur Förderung der wissenschaftlichen Forschung and Jubiläumsfonds 1930 der ETH.     

Nachweis einer nichtlinearen Komponente im globalen ERG der Katze bei Zuwachsreizen

Summary Nonlinear responses may be produced by incremental stimuli in the global electroretinogram of strongly light-adapted cat.     

Constant oxygen enhancement ratio during the mitotic cell cycle in X-rayedDrosophila melanogaster embryos

Zusammenfassung Drosophila-Embryonen zeigen eine mit dem Ablauf der Furchungsteilungen korrelierte Variation der Strahlenempfindlichkeit. Für alle Mitosestadien wurde eine Sauerstoff-Erhöhungsrate von rund 2 festgestellt. Dies zeigt, dass eine vermutete atmungsbedingte Variation des Sauerstofftgehaltes in den Zellen nicht am Zustandekommen der empfindlichkeitsvariation beteiligt ist.     

Prevention of graft-versus-host-disease with preserved graft-versus-leukemia-effect by ex vivo and in vivo modulation of CD4+ T-cells

This is the first report showing that an epitope-specific ex vivo modulation of an allogeneic hematopoietic stem cell graft by the anti-human CD4 antibody MAX.16H5 IgG₁ simultaneously facilitates the anti-tumor capacity of the graft (Graft-versus-leukemia effect, GvL) and the long-term suppression of the deleterious side effect Graft-versus-host-disease (GvHD). To distinguish and consolidate GvL from GvHD, the anti-human CD4 antibody MAX16.H5 IgG₁ was tested in murine GvHD and tumor models. The survival rate was significantly increased in recipients receiving a MAX.16H5 IgG₁ short-term (2 h) pre-incubated graft even when tumor cells were co-transplanted or when recipient mice were treated by MAX.16H5 IgG₁ before transplantation. After engraftment, regulatory T-cells are generated only supporting the GvL effect. It was also possible to transfer the immune tolerance from GvHD-free recipient chimeras into third party recipient mice without the need of reapplication of MAX.16H5 IgG₁ anti-human CD4 antibodies. These findings are also benefical for patients with leukemia when no matched related or unrelated donor is available and provides a safer allogeneic HSCT, which is more effective against leukemia. It also facilitates allogeneic (stem) cell transplantations for other indications (e.g., autoimmune-disorders).