Dieback of Fraxinus excelsior

Ash dieback caused by Hymenoscyphus pseudoalbidus (anamorph Chalara fraxinea) is a disease that has emerged during the past twenty years. It was first observed in Poland and has expanded over most of the distribution area of European ash (Fraxinus excelsior) in Europe. This thesis comprises four scientific papers. The first reports the production of a phytotoxin, viridiol, by the fungus, and shows that it causes necrotic spots on ash cotyledons. The second paper describes a working tool, a species-specific DNA primer situated in the internal transcribed spacer (ITS) region of the ribosomal DNA, which can be used to detect the fungus in diseased host material and confidently identify fungal cultures. In the third paper, microsatellites and arbitrary primed PCR were used to investigate the genetic population structure of the fungus. The genetic variation was evenly distributed in the whole European population, implying a high level of gene flow. Double alleles in apothecia compared with single alleles in mycelia cultures strongly indicated sexual reproduction. H. pseudoalbidus was clearly distinct from the native closely related Hymenoscyphus albidus and it is unlikely that the disease is derived from a H. albidus ancestry. The low number of microsatellite alleles per locus indicated a recent founder effect in H. pseudoalbidus. In the fourth paper disease development was surveyed in 261 naturally infected ash trees over a 32 month period. A clear seasonal pattern was demonstrated, with lesion activity and growth rate peaking during the summer. A substantial proportion of the lesions ceased to develop, often when the lesion reached a branch base; however the rate at which new lesions emerged was greater than the rate at which lesions entered a resting phase. During the course of the survey a third of the trees died and only a few seedlings remained healthy. In addition, the lower temperature limit for the fungus in culture was estimated to be 0.5°C

Digital distinctions: mechanisms of difference in digital media use

This article aims at understanding to understand the distinctive mechanisms of digital media use, seen in relation to cultural practices at large. The empirical material is a survey study of university students at the Business Administration, Media and Communication Studies, Political Science and Philosophy departments at Södertörn University, Sweden. The empirical analysis deals with the students’ digital media use and preferences, and how these are related to their broader cultural practices and preferences. Specific attention is paid to the webpages the students mention in the survey, and how these are distributed among the groups. By showing detailed information on these areas, the mechanisms of difference of digital media use are revealed

Sensorial Organization as an Ethics of Space: Digital Media in Everyday Life

This article outlines an analysis of the ethical organization of digital media and social and individual space in everyday life. This is made from a perspective of an ‘ethics of the ordinary’, highlighting the mundane negotiations and practices conducted to maintain a ‘good life’ with the media. The analysis shows a sensorial organization of space is conducted in relation to social space, as well as individually. The interviewees use facilities provided by media technologies in order to organize space, as well as organize their media devices spatially in order to construct space for specific purposes, and maintain a good life. These results call for a deepened analysis of the sensorial dimensions of everyday space, in order to understand the ethical struggles of a life with digital media. It is important to include the full spectrum of sensorial experiences in our approach to everyday life and to take the sensorial experiences of ordinary media users into account in our analysis of space as part of an everyday ethics

Biocompatibility of a polymer based on Off-Stoichiometry Thiol-Enes + Epoxy (OSTE+) for neural implants.

The flexibility of implantable neural probes has increased during the last 10 years, starting with stiff materials such as silicone to more flexible materials like polyimide. We have developed a novel polymer based on Off-Stoichiometry Thiol-Enes + Epoxy (OSTE+, consisting of a thiol, two allyls, an epoxy resin and two initiators), which is up to 100 times more flexible than polyimide. Since a flexible neural probe should be more biocompatible than a stiff probe, an OSTE+ probe should be more biocompatible than one composed of a more rigid material. We have investigated the toxicity of OSTE+ as well as of OSTE+ that had been incubated in water for a week (OSTE+H2O) using MTT assays with mouse L929 fibroblasts. We found that OSTE+ showed cytotoxicity, but OSTE+H2O did not. Extracts were analyzed using LC-MS and GC-MS in order to identify leaked chemicals

Dissemination of Multidrug-Resistant Bacteria into the Arctic

We show that Escherichia coli isolates originating from Arctic birds carry antimicrobial drug resistance determinants. This finding implies that dissemination of drug-resistant bacteria is worldwide. Resistance genes can be found even in a region where no selection pressure for resistance development exists

Low production of reactive oxygen species in granulocytes is associated with organ damage in systemic lupus erythematosus

Introduction: Polymorphonuclear leukocytes (PMN) are main effector cells in the acute immune response. While the specific role of PMN in systemic lupus erythematosus (SLE) and autoimmunity is still unclear, their importance in chronic inflammation is gaining more attention. Here we investigate aspects of function, bone marrow release and activation of PMN in patients with SLE. Methods: The following PMN functions and subsets were evaluated using flow cytometry; (a) production of reactive oxygen species (ROS) after ex vivo stimulation with phorbol 12-myristate 13-acetate (PMA) or Escherichia coli (E. coli); (b) capacity to phagocytose antibody-coated necrotic cell material; (c) PMN recently released from bone marrow, defined as percentage of CD10(-)D16(low) in peripheral blood, and (d) PMN activation markers; CD11b, CD62L and C5aR. Results: SLE patients (n = 92) showed lower ROS production compared with healthy controls (n = 38) after activation ex vivo. The ROS production was not associated with corticosteroid dose or other immunotherapies. PMA induced ROS production was significantly reduced in patients with severe disease. In contrast, neither ROS levels after E. coli activation, nor the capacity to phagocytose were associated with disease severity. This suggests that decreased ROS production after PMA activation is a sign of changed PMN behaviour rather than generally impaired functions. The CD10(-)CD16(low) phenotype constitute 2% of PMN in peripheral blood of SLE patients compared with 6.4% in controls, indicating a decreased release of PMN from the bone marrow in SLE. A decreased expression of C5aR on PMN was observed in SLE patients, pointing towards in vivo activation. Conclusions: Our results indicate that PMN from SLE patients have altered function, are partly activated and are released abnormally from bone marrow. The association between low ROS formation in PMN and disease severity is consistent with findings in other autoimmune diseases and might be considered as a risk factor

Increased Level of Myeloid-Derived Suppressor Cells, Programmed Death Receptor Ligand 1/Programmed Death Receptor 1, and Soluble CD25 in Sokal High Risk Chronic Myeloid Leukemia

Peer reviewe

Increased Level of Myeloid-Derived Suppressor Cells, Programmed Death Receptor Ligand 1/Programmed Death Receptor 1, and Soluble CD25 in Sokal High Risk Chronic Myeloid Leukemia

Peer reviewe