Pneumocystis Murina Infection in Immunodeficient Mice in a Closed Barrier Unit: a Case Report

Pneumocystis is an important pathogen in immunocompromised individuals. In colonies of immunodeficient  mice, P. murina can cause wasting disease and make the breeding and maintenance of immunodeficient  animals difficult, unless they are continuously treated with sulfadiazin/trimethoprim. At University  of Aarhus immunodeficient and immunocompetent mice were co-housed in a barrier unit. The facility was  closed for entrance of animals (except for embryos for embryo transfer) and the entrance for personnel was  highly restricted. The breeding performance of immunodeficient animals was comparable to that of the  immunocompetent mice for a period of more than 3 years, until wasting disease and decreased litter size  specifically in the breeding colony of immunodeficient mice occurred. Clinical symptoms of affected mice  included laboured breathing, hunched up position, unwillingness to move, and ruffled coat. Pneumocystis  infection was confirmed by histological examination and PCR. The partial sequence of the mitochondrial  large subunit rRNA gene obtained (GenBank accession no AF548626) displayed 99 % identity to that of  Pneumocystis murina (formerly Pneumocystis carinii f.sp.muris) found in laboratory mice. The immunodeficient  animals were removed from the barrier and treated with sulfadiazin/trimethoprim in a separate  unit. After the removal of immunodeficient animals, Pneumocystis could not be detected by PCR in the  remaining animals. Our data add to the growing evidence that immunocompetent animals harboring Pneumocystis  as a subclinical infection may be reservoirs for this organism. Still it remains to be determined  how the infection was introduced and whether a latent infection can persist or the outbreak was caused by  leakage in the barrier.

Stratigraphy, structure and metamorphism of Archean rocks at Rainy Lake, Ontario

The rocks of the Rainy Lake area have been deformed during three distinctive episodes. Minor structures provide the geometry which characterizes each episode. The youngest structures include regional faults, a crenulation cleavage, kink bands and minor F[subscript 3] folds. These D[subscript 3] structures are superimposed on structures of the D[subscript 2] episode. These include dominant F[subscript 2] folds having axes lying in a penetrative cleavage which parallels the axial surfaces of the folds. Some F[subscript 2] folds have a downward structural facing which is evidence that the stratigraphic succession at Rainy Lake is overturned at a regional scale. It is proposed that this inversion took place during a D[subscript 1] deformation by the formation of large F[subscript1] fold nappes. Minor D[subscript1] structures are difficult to document. The rocks of the region were metamorphosed simultaneously with much of the deformation. The distribution of index minerals defines the boundaries of the biotite, staurolite-cordierite and sillimanite-muscovite zones. The non-parallel distribution of metamorphic minerals may be explained by the non-parallelism of isotherms and isobars during medium grade metamorphism. These new data support the view that the Coutchiching biotite schists at Rainy Lake are stratigraphically younger than metavolcanic rocks of the Keewatin Group although they presently underlie the Keewatin structurally. This observation resolves a part of the historically important ”Seine-Coutchiching problem”

Det ubevidste i objektrelationsteorien

The article contains an account of the fate that the concept of the unconscious has undergone in the theories of Melanie Klein and D.W. Winnicott. On the basis of a statement of aspects of Freud's conception of the unconscious, an account of the Kleiniancomprehension of unconscious phantasies and their roles in the subject's internal world is given. Furthermore we present some theoretical problems related to the concept of internal objects. Finally we discuss the position of the unconscious in Winnicott'stheory. Here it is argued that Winnicott's focus of interest moves to the intermediate area between internal world and external reality. In this context we expound the essential splitting in the True and the False Self and the relation of these concepts to the Freudian formulations of the psychical apparatus.Artiklen rummer en fremstilling af den skæbne, begrebet det ubevidste har undergået i Melanie Kleins og D. W. Winnicotts teorier.På basis af en redegørelse for aspekter af Freuds tænkning om det ubevidste beskrives den kleinianske forståelse af ubevidste fantasier og deres rolle i subjektets indre verden. Der gives desuden en redegørelse for teoretiske problemer i forbindelse med begrebet om indre objekter. Endelig diskuteres begrebet det ubevidstes status i Winnicotts teori. Her argumenteres for, at Winnicotts interessefokus flyttes til det mellemliggende område mellem indre verden og ydre realitet. I denne sammenhæng redegøres for den centrale spaltning i det sande og falske selv og begrebernes relation til Freuds opdelinger af det psykiske apparat

Comparable early-stage decomposition but contrasting underlying drivers between surface and cave habitats along an elevational gradient

Decomposition is a major contributor to ecosystem respiration, determining the carbon emission and nutrient cycling rates. Our current understanding of decomposition dynamics and their underlying drivers has mainly focused on surface habitats but largely ignored in subterranean environments. Here we studied abiotic and microbial drivers of early-stage litter decomposition inside and outside caves along an elevational gradient in Tenerife. We found comparable decomposition rates (k) and litter stabilizing factors (S), with contrasting drivers and elevational variation. At the surface, we observed a mid-elevational trend in k, which tended to correlate with water availability, cooler temperatures, nutrient availability, and surface-specific bacterial taxa. In sharp contrast, caves showed no elevational impact nor influence of abiotic parameters and bacterial communities on k. Despite this, we found higher levels of S in caves, which were associated mainly with reduced water availability, lower temperatures and cave-specific bacterial taxa, indicating that conditions in caves are strongly linked with carbon storage. Our findings imply that our current perception of terrestrial habitat-based carbon cycling are underestimating the net carbon budget in areas with caves. Disentangling the role of the environment on decomposition in caves is key to fully characterize their roles in nutrient cycling and to understand how increasing anthropogenic pressures will affect fundamental processes in subterranean ecosystems.info:eu-repo/semantics/publishedVersio

Nutrient-limited subarctic caves harbour more diverse and complex bacterial communities than their surface soil

Background: Subarctic regions are particularly vulnerable to climate change, yet little is known about nutrient availability and biodiversity of their cave ecosystems. Such knowledge is crucial for predicting the vulnerability of these ecosystems to consequences of climate change. Thus, to improve our understanding of life in these habitats, we characterized environmental variables, as well as bacterial and invertebrate communities of six subarctic caves in Northern Norway. Results: Only a minuscule diversity of surface-adapted invertebrates were found in these caves. However, the bacte‑ rial communities in caves were compositionally diferent, more diverse and more complex than the nutrient-richer surface soil. Cave soil microbiomes were less variable between caves than between surface communities in the same area, suggesting that the stable cave environments with tougher conditions drive the uniform microbial communi‑ ties. We also observed only a small proportion of cave bacterial genera originating from the surface, indicating unique cave-adapted microbial communities. Increased diversity within caves may stem from higher niche specialization and levels of interdependencies for nutrient cycling among bacterial taxa in these oligotrophic environments. Conclusions: Taken together this suggest that environmental changes, e.g., faster melting of snow as a result of global warming that could alter nutrient infux, can have a detrimental impact on interactions and dependencies of these complex communities. This comparative exploration of cave and surface microbiomes also lays the founda‑ tion to further investigate the long-term environmental variables that shape the biodiversity of these vulnerable ecosystems.info:eu-repo/semantics/publishedVersio