The extent of vegetation openness in past European landscapes is widely debated. In particular, the temperate forest biome has traditionally been defined as dense, closed-canopy forest; however,... Show moreThe extent of vegetation openness in past European landscapes is widely debated. In particular, the temperate forest biome has traditionally been defined as dense, closed-canopy forest; however, some argue that large herbivores maintained greater openness or even wood-pasture conditions. Here, we address this question for the Last Interglacial period (129,000–116,000 years ago), before Homo sapiens–linked megafauna declines and anthropogenic landscape transformation. We applied the vegetation reconstruction method REVEALS to 96 Last Interglacial pollen records. We found that light woodland and open vegetation represented, on average, more than 50% cover during this period. The degree of openness was highly variable and only partially linked to climatic factors, indicating the importance of natural disturbance regimes. Our results show that the temperate forest biome was historically heterogeneous rather than uniformly dense, which is consistent with the dependency of much of contemporary European biodiversity on open vegetation and light woodland. Show less
Klein Haarhuis, C.M.; Bernards, B.J.T.H.; Winter, H. 2016
RATIONALE Chronic obstructive pulmonary disease patients and in particular smokers are more susceptible to respiratory infections contributing to acute exacerbations of disease. The... Show moreRATIONALE Chronic obstructive pulmonary disease patients and in particular smokers are more susceptible to respiratory infections contributing to acute exacerbations of disease. The immunoproteasome is a specialized type of proteasome destined to improve major histocompatibility complex (MHC) class I-mediated antigen presentation for the resolution of intracellular infections. OBJECTIVES To characterize immunoproteasome function in COPD and its regulation by cigarette smoke. METHODS Immunoproteasome expression and activity were determined in bronchoalveolar lavage (BAL) and lungs of human donors, COPD, and IPF patients, as well as in cigarette smoke-exposed mice. Smoke-mediated alteration of immunoproteasome activity and MHC I surface expression were analysed in human blood-derived macrophages. Immunoproteasome-specific MHC I antigen presentation was evaluated in spleen and lung immune cells that had been smoke-exposed in vitro or in vivo. MEASUREMENTS AND MAIN RESULTS Immunoproteasome and MHC I mRNA expression was reduced in BAL cells of COPD patients and in isolated alveolar macrophages of COPD and IPF patients. Exposure of immune cells to cigarette smoke extract in vitro reduced immunoproteasome activity and impaired immunoproteasome-specific MHC I antigen presentation. In vivo, acute cigarette smoke exposure dynamically regulated immunoproteasome function and MHC I antigen presentation in mouse BAL cells. End-stage COPD lungs showed markedly impaired immunoproteasome activities. CONCLUSIONS We here show for the first time that the activity of the immunoproteasome is impaired by cigarette smoke resulting in reduced MHC I antigen presentation. Regulation of immunoproteasome function by cigarette smoke may thus alter adaptive immune responses and add to prolonged infections and exacerbations in COPD and IPF. Show less
