Long term impact of residue management on soil organic carbon stocks and nitrous oxide emissions from European croplands.

Application of crop residues to agricultural fields is a significant source of the greenhouse gas nitrous oxide (NO) and an essential factor affecting the soil organic carbon (SOC) balance. Here we present a biogeochemical modelling study assessing the impact of crop residue management on soil C stocks and NO fluxes for EU-27 using available information on soils, management and climate and by testing various scenarios of residue management. Three biogeochemical models, i.

Flow Cytometry and Confocal Imaging Analysis of Low Wnt Expression in Axin2-mTurquoise2 Reporter Thymocytes.

Measuring Wnt expression levels is essential when trying to identify or test new Wnt therapeutic targets. Previous studies have shown that canonical Wnt signaling operates via a dosage-driven mechanism, motivating the need to study and measure Wnt signaling in various cell types. Although several reporter models have been proposed to represent physiological Wnt expression, either the genetic context or the reporter protein highly influenced the validity, accuracy, and flexibility of these tools.

Development of an model to study clonal lineage relationships in hematopoietic cells using mice.

Hematopoietic stem cells maintain the homeostasis of all blood cell progeny during development and repopulation-demanding events. To study the lineage relationships during hematopoiesis, increasingly complex cell tracing models are being developed. In this study, we describe adaptations to the original mouse model, which subsequently offers a relatively easy approach to study low complexity clonality during hematopoiesis, with special focus on B and T lymphocyte development.

Estimating nitrogen flows of agricultural soils at a landscape level - A modelling study of the Upper Enns Valley, a long-term socio-ecological research region in Austria.

This paper explores the fate of reactive nitrogen (Nr) on the landscape scale of present agricultural production practice on arable and grassland soils. We use the soil modelling tool LandscapeDNDC (landscape scale DeNitrification-DeComposition model) to quantify resulting flows of Nr distributed to the atmosphere, hydrosphere and the crops. Test area is a watershed in the Austrian Alps characterized by arable production in the low-lying areas and grassland in the mountains.

Sustained cross-presentation capacity of murine splenic dendritic cell subsets in vivo.

An exclusive feature of dendritic cells (DCs) is their ability to cross-present exogenous antigens in MHC class I molecules. We analyzed the fate of protein antigen in antigen presenting cell (APC) subsets after uptake of naturally formed antigen-antibody complexes in vivo. We observed that murine splenic DC subsets were able to present antigen in vivo for at least a week.

C1q-Dependent Dendritic Cell Cross-Presentation of In Vivo-Formed Antigen-Antibody Complexes.

Dendritic cells (DCs) are specialized in Ag engulfment via a wide variety of uptake receptors on their cell surface. In the present study we investigated Ag uptake and presentation of in vivo-formed Ag-Ab complexes by i.v.

A modeling study on mitigation of N2O emissions and NO3 leaching at different agricultural sites across Europe using LandscapeDNDC.

The identification of site-specific agricultural management practices in order to maximize yield while minimizing environmental nitrogen losses remains in the center of environmental pollution research. Here, we used the biogeochemical model LandscapeDNDC to explore different agricultural practices with regard to their potential to reduce soil N2O emissions and NO3 leaching while maintaining yields. In a first step, the model was tested against observations of N2O emissions, NO3 leaching, soil micrometeorology as well as crop growth for eight European cropland and grassland sites.

Estimation and mitigation of N2O emission and nitrate leaching from intensive crop cultivation in the Haean catchment, South Korea.

Considering intensive agricultural management practices and environmental conditions, the LandscapeDNDC model was applied for simulation of yields, N2O emission and nitrate leaching from major upland crops and temperate deciduous forest of the Haean catchment, South Korea. Fertilization rates were high (up to 314 kg N ha(-1) year(-1)) and resulted in simulated direct N2O emissions from potato, radish, soybean and cabbage fields of 1.9 and 2.

Isolation of human and mouse hematopoietic stem cells.

Hematopoietic stem cells (HSC) are rare with estimated frequencies of 1 in 10,000 bone marrow cells and 1 in every 100,000 blood cells. The most important characteristic of HSC is their capacity to provide complete restoration of all blood cell lineages after bone marrow ablation. Therefore they are considered as the ideal targets for various clinical applications including stem cell transplantation and gene therapy.

Wnt3a deficiency irreversibly impairs hematopoietic stem cell self-renewal and leads to defects in progenitor cell differentiation.

Canonical Wnt signaling has been implicated in various aspects of hematopoiesis. Its role is controversial due to different outcomes between various inducible Wnt-signaling loss-of-function models and also compared with gain-of-function systems. We therefore studied a mouse deficient for a Wnt gene that seemed to play a nonredundant role in hematopoiesis.

Enforced expression of GATA3 allows differentiation of IL-17-producing cells, but constrains Th17-mediated pathology.

The zinc-finger transcription factor GATA3 serves as a master regulator of T-helper-2 (Th2) differentiation by inducing expression of the Th2 cytokines IL-4, IL-5 and IL-13 and by suppressing Th1 development. Here, we investigated how GATA3 affects Th17 differentiation, using transgenic mice with enforced GATA3 expression. We activated naïve primary T cells in vitro in the presence of transforming growth factor-beta and IL-6, and found that enforced GATA3 expression induced co-expression of Th2 cytokines in IL-17-producing T cells.

Wnt signaling in the thymus is regulated by differential expression of intracellular signaling molecules.

Wnt signaling is essential for T cell development in the thymus, but the stages in which it occurs and the molecular mechanisms underlying Wnt responsiveness have remained elusive. Here we examined Wnt signaling activity in both human and murine thymocyte populations by determining beta-catenin levels, Tcf-reporter activation and expression of Wnt-target genes. We demonstrate that Wnt signaling occurs in all thymocyte subsets, including the more mature populations, but most prominently in the double negative (DN) subsets.

Human thymus contains multipotent progenitors with T/B lymphoid, myeloid, and erythroid lineage potential.

It is a longstanding question which bone marrow-derived cell seeds the thymus and to what level this cell is committed to the T-cell lineage. We sought to elucidate this issue by examining gene expression, lineage potential, and self-renewal capacity of the 2 most immature subsets in the human thymus, namely CD34+ CD1a- and CD34+ CD1a+ thymocytes. DNA microarrays revealed the presence of several myeloid and erythroid transcripts in CD34+ CD1a- thymocytes but not in CD34+ CD1a+ thymocytes.

Ig gene rearrangement steps are initiated in early human precursor B cell subsets and correlate with specific transcription factor expression.

The role of specific transcription factors in the initiation and regulation of Ig gene rearrangements has been studied extensively in mouse models, but data on normal human precursor B cell differentiation are limited. We purified five human precursor B cell subsets, and assessed and quantified their IGH, IGK, and IGL gene rearrangement patterns and gene expression profiles. Pro-B cells already massively initiate D(H)-J(H) rearrangements, which are completed with V(H)-DJ(H) rearrangements in pre-B-I cells.

New insights on human T cell development by quantitative T cell receptor gene rearrangement studies and gene expression profiling.

To gain more insight into initiation and regulation of T cell receptor (TCR) gene rearrangement during human T cell development, we analyzed TCR gene rearrangements by quantitative PCR analysis in nine consecutive T cell developmental stages, including CD34+ lin- cord blood cells as a reference. The same stages were used for gene expression profiling using DNA microarrays. We show that TCR loci rearrange in a highly ordered way (TCRD-TCRG-TCRB-TCRA) and that the initiating Ddelta2-Ddelta3 rearrangement occurs at the most immature CD34+CD38-CD1a- stage.

Age-related changes in the cellular composition of the thymus in children.

Background: T-cell development in the thymus is an extensively studied subject, mainly in mice. Nevertheless, the normal composition and cell numbers of the noninvoluted human thymus are largely unknown.

Objective: We aimed to gain insight into age-related changes in different thymic subpopulations and to provide reference values for the distribution of thymocyte subsets.

Wnt target genes identified by DNA microarrays in immature CD34+ thymocytes regulate proliferation and cell adhesion.

The thymus is seeded by very small numbers of progenitor cells that undergo massive proliferation before differentiation and rearrangement of TCR genes occurs. Various signals mediate proliferation and differentiation of these cells, including Wnt signals. Wnt signals induce the interaction of the cytoplasmic cofactor beta-catenin with nuclear T cell factor (TCF) transcription factors.