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1.
2.
Reductive dechlorination of 1,2-dichloroethane and chloroethane by cell suspensions of methanogenic bacteria 总被引:4,自引:0,他引:4
Christof Holliger Gosse Schraa Alfons J. M. Stams Alexander J. B. Zehnder 《Biodegradation》1990,1(4):253-261
Concentrated cell suspensions of methanogenic bacteria reductively dechlorinated 1,2-dichloroethane via two reaction-mechanisms: a dihalo-elimination yielding ethylene and two hydrogenolysis reactions yielding chloroethane and ethane, consecutively. The transformation of chloroethane to ethane was inhibited by 1,2-dichloroethane. Stimulation of methanogenesis caused an increase in the amount of dechlorination products formed, whereas the opposite was found when methane formation was inhibited. Cells of Methanosarcina barkeri grown on H2/CO2 converted 1,2-dichloroethane and chloroethane at higher rates than acetate or methanol grown cells.Abbreviations BrES
2-bromoethanesulfonic acid
- CA
chloroethane
- 1,2-DCA
1,2-dichloroethane
- F430
Ni(II)tetrahydro-(12, 13)-corphin with an uroporphinoid (III) ligand skeleton 相似文献
3.
Eighteen German families with a history of paramyotonia congenita (PC) were characterised by genetic und mutational analysis at the SCN4A locus, which encodes the -subunit of the adult skeletal muscle sodium channel. We concentrated our analysis primarily on these families to test the hypothesis that a predominance of one common mutation occurs in all German PC families and that this mutation arose in a common ancestor originating in the North-West of the country. The present eighteen PC families exhibit two different mutations (R1448C and R1448H) on various SCN4A dinucleotide repeat haplotypes and therefore the majority of the mutations probably occurred independently. However, the R1448H mutation is extremely frequent in the North-West of Germany (Ravensberger Land) on a specific SCN4A microsatellite haplotype, indicating a founder effect within this subpopulation. Our results suggest that the R1448C/R1448H mutations are by far the most common to be associated with the PC phenotype in the German population.This paper is dedicated to Professor Dr. Dr. Peter Emil Becker on the occasion of this 85th birthday 相似文献
4.
This article presents for the first time a modified protocol for RNase protection analysis that allows the substitution of32P with33P without loss of the high sensitivity of this method achieved with32P. With this protocol, we were able to detect at least 1 pg of specific mRNA. In the RNase protection analysis33P labeled riboprobes are more advantageous with regard to an easier handling and better resolution. 相似文献
5.
A role for fibronectin-leucine-rich transmembrane cell-surface proteins in homotypic cell adhesion 总被引:4,自引:0,他引:4
The fibronectin-leucine-rich transmembrane (FLRT) family of leucine-rich repeat (LRR) proteins is implicated in fibroblast growth factor (FGF) signalling, early embryonic development and neurite outgrowth. Here, we have analysed whether FLRTs may also function in cell adhesion. We find that FLRT proteins can physically interact and that FLRT-transfected cultured cells sort out from non-transfected cells, suggesting a change in adhesive properties. A similar sorting effect is also observed in Xenopus embryos and tissue aggregates. FLRT-mediated cell sorting is calcium dependent and substrate independent. Deletion analysis indicates that cell sorting requires the LRR domains, which are dispensable for FLRT-mediated FGF signalling. Conversely, sorting is independent of the cytoplasmic domain, which is essential for FLRT-induced signalling. Therefore, FLRT-mediated FGF signal transduction and homotypic cell sorting can be molecularly uncoupled. The results indicate that FLRT proteins have a dual role, promoting FGF signalling and modulating homotypic cell adhesion. 相似文献
6.
Neurons exhibit diverse intrinsic dynamics, which govern how they integrate synaptic inputs to produce spikes. Intrinsic dynamics are often plastic during development and learning, but the effects of these changes on stimulus encoding properties are not well known. To examine this relationship, we simulated auditory responses to zebra finch song using a linear-dynamical cascade model, which combines a linear spectrotemporal receptive field with a dynamical, conductance-based neuron model, then used generalized linear models to estimate encoding properties from the resulting spike trains. We focused on the effects of a low-threshold potassium current (KLT) that is present in a subset of cells in the zebra finch caudal mesopallium and is affected by early auditory experience. We found that KLT affects both spike adaptation and the temporal filtering properties of the receptive field. The direction of the effects depended on the temporal modulation tuning of the linear (input) stage of the cascade model, indicating a strongly nonlinear relationship. These results suggest that small changes in intrinsic dynamics in tandem with differences in synaptic connectivity can have dramatic effects on the tuning of auditory neurons. 相似文献
7.
Driving factors of a vegetation shift from Scots pine to pubescent oak in dry Alpine forests 总被引:2,自引:0,他引:2
Andreas Rigling Christof Bigler Britta Eilmann Elisabeth Feldmeyer‐Christe Urs Gimmi Christian Ginzler Ulrich Graf Philipp Mayer Giorgio Vacchiano Pascale Weber Thomas Wohlgemuth Roman Zweifel Matthias Dobbertin 《Global Change Biology》2013,19(1):229-240
An increasing number of studies have reported on forest declines and vegetation shifts triggered by drought. In the Swiss Rhone valley (Valais), one of the driest inner‐Alpine regions, the species composition in low elevation forests is changing: The sub‐boreal Scots pine (Pinus sylvestris L.) dominating the dry forests is showing high mortality rates. Concurrently the sub‐Mediterranean pubescent oak (Quercus pubescens Willd.) has locally increased in abundance. However, it remains unclear whether this local change in species composition is part of a larger‐scale vegetation shift. To study variability in mortality and regeneration in these dry forests we analysed data from the Swiss national forest inventory (NFI) on a regular grid between 1983 and 2003, and combined it with annual mortality data from a monitoring site. Pine mortality was found to be highest at low elevation (below 1000 m a.s.l.). Annual variation in pine mortality was correlated with a drought index computed for the summer months prior to observed tree death. A generalized linear mixed‐effects model indicated for the NFI data increased pine mortality on dryer sites with high stand competition, particularly for small‐diameter trees. Pine regeneration was low in comparison to its occurrence in the overstorey, whereas oak regeneration was comparably abundant. Although both species regenerated well at dry sites, pine regeneration was favoured at cooler sites at higher altitude and oak regeneration was more frequent at warmer sites, indicating a higher adaptation potential of oaks under future warming. Our results thus suggest that an extended shift in species composition is actually occurring in the pine forests in the Valais. The main driving factors are found to be climatic variability, particularly drought, and variability in stand structure and topography. Thus, pine forests at low elevations are developing into oak forests with unknown consequences for these ecosystems and their goods and services. 相似文献
8.
What is the relationship between the complexity and the fitness of evolved organisms, whether natural or artificial? It has been asserted, primarily based on empirical data, that the complexity of plants and animals increases as their fitness within a particular environment increases via evolution by natural selection. We simulate the evolution of the brains of simple organisms living in a planar maze that they have to traverse as rapidly as possible. Their connectome evolves over 10,000s of generations. We evaluate their circuit complexity, using four information-theoretical measures, including one that emphasizes the extent to which any network is an irreducible entity. We find that their minimal complexity increases with their fitness. 相似文献
9.
Christoph Domschke Yingzi Ge Isa Bernhardt Sarah Schott Sophia Keim Simone Juenger Mariana Bucur Luisa Mayer Maria Blumenstein Joachim Rom Joerg Heil Christof Sohn Andreas Schneeweiss Philipp Beckhove Florian Schuetz 《Cancer immunology, immunotherapy : CII》2013,62(6):1053-1060
Background
The bone marrow (BM) of breast cancer patients harbors tumor-reactive memory T cells (TCs) with therapeutic potential. We recently described the immunologic effects of adoptive transfer of ex vivo restimulated tumor-reactive memory TCs from the BM of 12 metastasized breast cancer patients in a clinical phase-I study. In this trial, adoptive T cell transfer resulted in the occurrence of circulating tumor antigen-reactive type-1 TCs. We here describe the long-term clinical outcome and its correlation with tumor-specific cellular immune response in 16 metastasized breast cancer patients, including 12 included in the original study.Methods
Sixteen metastatic breast cancer patients with preexisting tumor-reactive BM memory TCs were included into the study. The study protocol involved one transfusion of TCs which were reactivated in vitro with autologous dendritic cells pulsed with lysates of MCF-7 breast cancer cells as source of tumor antigens. The presence of tumor-reactive memory TCs was analyzed by IFN-γ ELISpot assays.Results
Tumor-reactive memory TCs in the peripheral blood were induced de novo in 7/16 patients (44 %) after adoptive TC transfer. These patients were considered immunologic responders to the therapy. Positive adoptive immunotherapy (ADI) response was observed significantly more often in patients without bone metastases (p = 0.0051), in patients with high levels of tumor-reactive BM TCs prior to therapy (p = 0.036) and correlated significantly with the estimated numbers of transferred tumor-reactive TCs (p = 0.0021). After the treatment, we observed an overall median survival of 33.8 months in the total cohort with three patients alive at last follow-up and more than 7 years after ADI. Numbers of transferred tumor-reactive TCs correlated significantly with the overall survival of patients (p = 0.017). Patients with an immunologic response to ADI in the peripheral blood had a significantly longer median survival than nonresponders (median survival 58.6 vs. 13.6 months; p = 0.009).Conclusion
In metastasized breast cancer patients, adoptive transfer of BM TCs can induce the presence of tumor antigen-reactive type-1 TCs in the peripheral blood. Patients with immunologic response after ADI show a significantly longer overall survival. Patients with bone metastases significantly less frequently respond to the treatment and, therefore, might not be optimal candidates for ADI. Although the present study does not yet prove the therapeutic effect of ADI, these findings shed light on the relation between immune response and cancer prognosis and suggest that transfer of reactivated BM TCs might bear therapeutic potential. 相似文献10.
Eric Allan Wolfgang W. Weisser Markus Fischer Ernst-Detlef Schulze Alexandra Weigelt Christiane Roscher Jussi Baade Romain L. Barnard Holger Beßler Nina Buchmann Anne Ebeling Nico Eisenhauer Christof Engels Alexander J. F. Fergus Gerd Gleixner Marlén Gubsch Stefan Halle Alexandra M. Klein Ilona Kertscher Annely Kuu Markus Lange Xavier Le Roux Sebastian T. Meyer Varvara D. Migunova Alexandru Milcu Pascal A. Niklaus Yvonne Oelmann Esther Pašalić Jana S. Petermann Franck Poly Tanja Rottstock Alexander C. W. Sabais Christoph Scherber Michael Scherer-Lorenzen Stefan Scheu Sibylle Steinbeiss Guido Schwichtenberg Vicky Temperton Teja Tscharntke Winfried Voigt Wolfgang Wilcke Christian Wirth Bernhard Schmid 《Oecologia》2013,173(1):223-237
In order to predict which ecosystem functions are most at risk from biodiversity loss, meta-analyses have generalised results from biodiversity experiments over different sites and ecosystem types. In contrast, comparing the strength of biodiversity effects across a large number of ecosystem processes measured in a single experiment permits more direct comparisons. Here, we present an analysis of 418 separate measures of 38 ecosystem processes. Overall, 45 % of processes were significantly affected by plant species richness, suggesting that, while diversity affects a large number of processes not all respond to biodiversity. We therefore compared the strength of plant diversity effects between different categories of ecosystem processes, grouping processes according to the year of measurement, their biogeochemical cycle, trophic level and compartment (above- or belowground) and according to whether they were measures of biodiversity or other ecosystem processes, biotic or abiotic and static or dynamic. Overall, and for several individual processes, we found that biodiversity effects became stronger over time. Measures of the carbon cycle were also affected more strongly by plant species richness than were the measures associated with the nitrogen cycle. Further, we found greater plant species richness effects on measures of biodiversity than on other processes. The differential effects of plant diversity on the various types of ecosystem processes indicate that future research and political effort should shift from a general debate about whether biodiversity loss impairs ecosystem functions to focussing on the specific functions of interest and ways to preserve them individually or in combination. 相似文献