Responses of ectomycorrhizal fungi to mineral substrates

Boreal forest soils are complex, heterogeneous growth substrates where organic and mineral components provide nutrient resources for soil organisms and plants. Mineral nutrients are cycled between living and dead organic components of the forest soil and weathering of soil minerals provides an important input of new resources, compensating for losses from the ecosystem. Predicting soil responses to changing climate and management practices is important to determine their effect on forest production. Models for this purpose are largely based on the concept of the soil solution as the interface controlling soil processes such as weathering and nutrient uptake by plants, whereas soil microbiology recognises microbial processes as the driving force in soil nutrient cycling. In boreal forests most tree root tips are colonised by ectomycorrhizal fungi. The mycelia of these symbiotic fungi mediate nutrient uptake by their tree hosts. These fungi are abundant in the organic layer of forest soils and ectomycorrhizal research has therefore largely focused on nutrient uptake from this horizon. Minerals in the soil may, however, also serve as nutrient resources for ectomycorrhizal fungi. Through combined chemical and physical processes fungi can affect nutrient availability by weathering minerals. This thesis describes a field experiment investigating the distribution of different ectomycorrhizal fungi in organic and mineral forest soil horizons, in vitro studies of fungal acidification of artificial substrates with different mineral element composition, microcosm studies of growth and carbon allocation in intact ectomycorrhizal systems colonising heterogeneous mineral substrates and a preliminary investigation of changes in surface micro-topography of minerals colonised by ectomycorrhizal hyphae. Half of the fungal species identified in the forest soil occurred exclusively in the mineral horizons. Mycelial growth, carbon allocation and substrate acidification by fungi colonising different mineral substrates in vitro and in microcosms appeared to be influenced by mineral element composition. Interpretation of possible modification of mineral surface micro-topography is more difficult but together the results obtained suggest that ectomycorrhizal fungi may contribute to the development of microenvironments on colonised mineral surfaces, where increased weathering can take place. Processes regulating nutrient availability in such microenvironments are different from those estimated from the bulk soil solution

Therapeutic creativity and the lived experience of grief in the collaborative fiction film Lost Property

This collaborative project aimed to represent the embodied experience of grief in a fiction film by drawing on research, and on the personal and professional experience of all involved: academics; an artist; bereavement therapists and counsellors; and professional actors, cinematographers, sound engineers and other film crew. By representing grief in a more phenomenologically minded manner, the project sought to capture the lived experience of loss on screen while contributing meaningfully to the discourse on practice-as-research. Hay, Dawson and Rosling used a collaborative fiction film and participatory action research to investigate whether storying loss, and representing it through narrative, images and embodied movement, is therapeutic. Participatory action research was beneficial in facilitating changes in the co-researchers’ thinking, feeling and practice, and in enabling participants to inhabit multiple roles in a manner that expanded their disciplinary boundaries. However, while the project’s effect on some of the participants demonstrated the ways that creativity and meaning making can support adaptive grieving, it also revealed the risks of using participatory action research and fiction film to investigate highly emotive topics such as grief

Stellenwert der kontrastmittelunterstützten Sonographie im Vergleich zur konventionellen B-Bild Sonographie in der Darstellung von Milzlazerationen bei Patienten mit traumatischen und nicht-traumatischen Milzverletzungen: eine retrospektiv deskriptive Studie

Das Krankheitsbild der traumatischen Milzverletzungen wurde bereits in vielen Studien untersucht und beschrieben (Tinkoff et al., 2008). Dahingegen treten die spontanen Milzverletzungen sehr viel seltener auf, Symptomatik, Diagnostik, Therapie und Verlauf wurden nur vereinzelt beschrieben (Cölle, 2003; Weaver et al., 2013; Wehbe et al., 2008). In dieser retrospektiven Studie wurden die Krankeitsbilder von 62 Patienten mit traumatischen und spontanen Milzverletzungen, die in einem gleichen Zeitraum in einem universitären Ultraschallabor diagnostiziert wurden, miteinander verglichen und analysiert. Der Fokus des Vergleiches lag auf der Klinik, dem sonographischen Erscheinungsbildes und Grading (sowohl im B-­‐Bild US als auch in der CEUS), der Therapie und dem Verlaufs. Es konnten deutliche Unterschiede bei den klinischen Daten hinsichtlich Alter, Grunderkrankungen und Verlauf gezeigt werden. So waren Patienten mit traumatischen MV jünger, hatten keine Splenomegalie, keine maligne Grundkrankheit und keine verletzungsbedingte Mortalität. Patienten mit spontaner MV waren älter, zeigten häufiger eine Splenomegalie, hatten vermehrt eine maligne Grunderkrankung und eine erhöhte Mortalität innerhalb der ersten vier Wochen nach Diagnose einer MV. Im sonographischen Erscheinungsbild konnten keine signifikanten Unterschiede zwischen traumatischen und spontanen Milzverletzungen festgestellt werden: Es handelt sich weitgehend um fokale, intraparenchymatös lokalisierte, vorwiegend echoarme oder isoechogene Läsionen. Sie weisen sich durch Inhomogenität in ansonsten homogenem Milzgewebe aus. In der CEUS heben sich MV durch fokale homogen echofreie Läsionen bzw. Areale mit fehlender Kontrastmittelanreicherung im Vergleich zum umgebenden Milzgewebe ab. Schwerwiegende Komplikationen wie Grad 4 Lazerationen traten in beiden Gruppen gleich häufig auf. Hinsichtlich des Stellenwert der CEUS im Vergleich mit der B-­‐Bild Sonographie konnte bestätigt werden, dass die CEUS der B-­‐Bild-­‐Sonographie überlegen war was die sichere Diagnosestellung und dem Grading der Milzverletzung betraf. Die CEUS beeinflusste in Subgruppen die Therapiewahl. Bei jedem Verdacht auf eine Milzverletzung sollte eine CEUS durchgeführt werden. Die Häufigkeit von unterschiedlichen Therapiemaßnahmen wie Splenektomie, interventionelle radiologische Prozeduren und klinisch/sonographischen Verlaufskontrollen variierten zwischen spontanen und traumatischen MV nicht. Abschließend kann gesagt werden, dass sich das Krankheitsbild der spontanen Milzverletzungen vor allem hinsichtlich der Klinik, dem Verlauf und der Prognose deutlich von dem Krankheitsbild der traumatischen Milzverletzungen unterscheidet. Hinsichtlich des sonographischen Erscheinungsbild im B-­‐Bild und CEUS zeigen sich identische Verletzungsmuster

Scientism recognizes evidence only of the quantitative/general variety

Rationale, aims and objectivesMcHugh and Walker introduced a model of knowledge to demonstrate that EBM is a form of scientism that ignores important sources of knowledge thereby impairing the practice of medicine. We study the development of this model and explore additional applications.MethodsReview of the relevant literature and identification of possible areas for fruitful application.ResultsWe show that the McHugh and Walker model is closely related to the model of evidence considered earlier by Upshur et al. We also indicate that the utility of this model is not limited to showing scientism distorts clinical practice. Several representative applications are identified, including psychotherapy, the Salk polio vaccine trial, and the placebo effect.ConclusionsPriority should be given to Upshur et al for the development of a model that has far‐reaching application to medical epistemology. It is shown that all four of the types of evidence considered—qualitative/personal, qualitative/general, quantitative/general, and quantitative/personal—are required to adequately characterize epistemology in medical research and practice.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154650/1/jep13330_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154650/2/jep13330.pd

Biochemical characterization and chemical inhibition o PfATP4-associated Na+-ATPase activity in Plasmodium falciparum membranes

The antimalarial activity of chemically diverse compounds, including the clinical candidate cipargamin, has been linked to the ATPase PfATP4 in the malaria-causing parasite Plasmodium falciparum. The characterization of PfATP4 has been hampered by the inability thus far to achieve its functional expression in a heterologous system. Here, we optimized a membrane ATPase assay to probe the function of PfATP4 and its chemical sensitivity. We found that cipargamin inhibited the Na+-dependent ATPase activity present in P. falciparum membranes from WT parasites and that its potency was reduced in cipargamin-resistant PfATP4-mutant parasites. The cipargamin-sensitive fraction of membrane ATPase activity was inhibited by all 28 of the compounds in the "Malaria Box" shown previously to disrupt ion regulation in P. falciparum in a cipargamin-like manner. This is consistent with PfATP4 being the direct target of these compounds. Characterization of the cipargamin-sensitive ATPase activity yielded data consistent with PfATP4 being a Na+ transporter that is sensitive to physiologically relevant perturbations of pH, but not of [K+] or [Ce2+]. With an apparent K-m for ATP of 0.2 mm and an apparent K-m for Na+ of 16 -17 mm, the protein is predicted to operate at below its half-maximal rate under normal physiological conditions, allowing the rate of Na+ efflux to increase in response to an increase in cytosolic [Na+]. In membranes from a cipargamin-resistant PfATP4-mutant line, the apparent K-m for Na+ is slightly elevated. Our study provides new insights into the biochemical properties and chemical sensitivity of an important new antimalarial drug target.This work was supported by an Australian Research Council Discovery Early Career Researcher Award (DE160101035 to A. M. L.), an Australian Research Council Linkage Project Grant (LP150101226 to K. K.), and a National Health and Medical Research Council Project Grant (1042272 to K. K.). The authors declare that they have no conflicts of interest with the contents of this article

'Big is beautiful' – an exploration with urban black community health workers in a South African township

OBJECTIVES: To explore perceptions about factors associated with body weight and body image among black female community health workers (CHWs) living and working in Khayelitsha, Cape Town. DESIGN: A descriptive, cross-sectional study. Setting. Khayelitsha, a black township in Cape Town, South Africa. SUBJECTS: Forty-four black, female, Xhosa-speaking CHWs working in Khayelitsha. Outcome measures. Anthropometric measures (height, weight, and waist circumference) were taken. Body mass index (BMI) was computed as a measure to estimate total body fat. Waist circumference was used as a measure of abdominal obesity. Focus groups were employed to explore beliefs and attitudes about body size. Information from the focus group discussions was used to develop a semi-structured questionnaire for individual interviews, which were conducted to validate the data from the focus groups, and to assess knowledge on causes and risk factors associated with obesity. A body satisfaction question was also included in the questionnaire. Body image was measured using body shape drawings (pictograms). RESULTS: Of the 44 women measured, 2 had normal weight (BMI 18.5 - 24.9 kg/m2), 2 were overweight (BMI 25 - 30 kg/m2), 25 were obese (BMI 30 - 40 kg/m2) and 15 were extremely obese (BMI ≥ ( 40 kg/m2). A moderately overweight shape (BMI 27 kg/m2) was preferred; this was associated with dignity, respect, confidence, beauty, and wealth. Perceived causes of obesity were eating the wrong food, skipping breakfast and worries about debts, husbands/partners and teenage children. Negative aspects of obesity included body aches and tiredness. CONCLUSION: This study emphasises the prevalence of obesity among urban black women in South Africa, particularly among CHWs. Socio-cultural, behavioural and environmental factors seem to influence the development of obesity in this population.Christian Aids in London and Provincial Administration of the Western Cape

Variation in hyphal production rather than turnover regulates standing fungal biomass in temperate hardwood forests

Soil fungi link above‐ and belowground carbon (C) fluxes through their interactions with plants and contribute to C and nutrient dynamics through the production, turnover, and activity of fungal hyphae. Despite their importance to ecosystem processes, estimates of hyphal production and turnover rates are relatively uncommon, especially in temperate hardwood forests. We sequentially harvested hyphal ingrowth bags to quantify the rates of Dikarya (Ascomycota and Basidiomycota) hyphal production and turnover in three hardwood forests in the Midwestern United States, where plots differed in their abundance of arbuscular (AM)‐ vs. ectomycorrhizal (ECM)‐associated trees. Hyphal production rates increased linearly with the percentage of ECM trees and annual production rates were 66% higher in ECM‐ than AM‐dominated plots. Hyphal turnover rates did not differ across the mycorrhizal gradient (plots varying in their abundance of AM vs. ECM trees), suggesting that the greater fungal biomass in ECM‐dominated plots relates to greater fungal production rather than slower fungal turnover. Differences in hyphal production across the gradient aligned with distinctly different fungal communities and activities. As ECM trees increased in dominance, fungi inside ingrowth bags produced more extracellular enzymes involved in degrading nitrogen (N)‐bearing relative to C‐bearing compounds, suggesting greater fungal (and possibly plant) N demand in ECM‐dominated soils. Collectively, our results demonstrate that shifts in temperate tree species composition that result in changes in the dominant type of mycorrhizal association may have strong impacts on Dikarya hyphal production, fungal community composition and extracellular enzyme activity, with important consequences for soil C and N cycling