Suchergebnisse

In semiarid agroecosystems of the Ebro valley (NE Spain) soils are characterized by low soil organic matter (SOM) and a weak structure. In this study we investigated the individual and combined effect of tillage system (no-tillage, NT; reduced tillage, RT; conventional tillage, CT) and cropping system (barley–fallow rotation at the Peñaflor site, PN-BF and continuous barley at the Peñaflor site, PN-BB) on soil organic carbon (SOC) storage as well as the physical protection of SOM fractions by soil aggregates in three long-term experimental sites. In both cropping systems, total SOC content was more than 30% higher in NT compared with CT in the 0- to 5-cm depth. The suppression of fallowing in the PN-BB cropping system led to a greater SOC stabilization only in NT. In all the three sites, greater proportion of water-stable macroaggregates (>250 µm) was found under NT than under CT in the 0- to 5-cm depth. Macroaggregate organic C concentration (250–2000 µm) was greater in NT compared with CT in the BB cropping system, but did not differ with tillage treatment in the PN-BF rotation. Greater proportion of microaggregates within macroaggregates in NT compared with CT was only found in the Agramunt site (AG). However, greater C stabilized inside these microaggregates was observed in AG, Selvanera site (SV), and PN-BB in the 0- to 5-cm depth. The results of this study demonstrate that in the semiarid Mediterranean agroecosystems of the Ebro valley, the adoption of NT together with the suppression of long-fallowing period can significantly increase the amount of SOC stabilized in the soil surface and improve soil structure and aggregation. ; This research was supported by the Comisión Interministerial de Ciencia y Tecnología of Spain (Grants AGL2001-2238-CO2-01, AGL 2004-07763-C02-02 and AGL2007-66320-CO2-02/AGR) and the European Union (FEDER funds). ; Peer reviewed

Additional Supporting Information may be found in the online version of this article: Table S1. Clinical and sputum characteristics of lung biopsy groups. Table S2. Demographic information for the Dutch cohort used for serum analyses. Table S3. Demographics information for the UK cohort used for serum analyses. ; RATIONALE: Genetic polymorphisms in the asthma susceptibility gene, urokinase plasminogen activator receptor (uPAR/PLAUR) have been associated with lung function decline and uPAR blood levels in asthma subjects. Preliminary studies have identified uPAR elevation in asthma; however a definitive study regarding which clinical feature of asthma uPAR may be driving is currently lacking. OBJECTIVES: We aimed to comprehensively determine the uPAR expression profile in asthma and control subjects utilising bronchial biopsies and serum, and to relate uPAR expression to asthma clinical features. METHODS: uPAR levels were determined in control (n=9) and asthmatic (n=27) bronchial biopsies using immunohistochemistry, with a semi-quantitative score defining intensity in multiple cell types. Soluble cleaved (sc)uPAR levels were determined in serum through ELISA in UK (cases n=129; controls n=39) and Dutch (cases n=441; controls n=96) cohorts. MEASUREMENTS AND MAIN RESULTS: In bronchial tissue, uPAR was elevated in inflammatory cells in the lamina propria (P=0.0019), bronchial epithelial (P=0.0002) and airway smooth muscle cells (P=0.0352) of asthma patients, with uPAR levels correlated between the cell types. No correlation with disease severity or asthma clinical features was identified. scuPAR serum levels were elevated in asthma patients (1.5 fold; P=0.0008) and we identified an association between high uPAR serum levels and severe, non-atopic disease. CONCLUSIONS: This study provides novel data that elevated airway and blood uPAR in asthma is particularly related to severe, non-atopic asthma. The findings warrant further investigation and may provide a therapeutic opportunity for this refractory population. ; STEPS scholarship part financed by the European Union – European Social Fund (ESF) under Operational Programme II – Cohesion Policy 2007–2013, 'Empowering People for More Jobs and a Better Quality of Life' Asthma UK, Grant 08/017. The study is also part funded by the National Institute for Health Research Leicester Biomedical Research Unit, UK. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or Department of Health. ; Peer-reviewed ; Publisher Version