Vegetation on Alpine rock glacier surfaces: a contribution to abundance and dynamics on extreme plant habitats

In the area of Piz Corvatsch (Upper Engadin, Grisons, Switzerland), the actual vegetation on active and inactive rock glacier surfaces has been mapped. The floristic composition (vascular plants and lichens) of the different rock glacier surfaces has been mapped and compared with photogrammetrical measurements of surface movements of the active rock glaciers. In general, the active rock glacier surfaces show a very low cover of vascular plants. Most of them are located at the edge and at the front of the rock glacier where fine-grained soil material occurs in small pokkets.

Lichenometry has been used as an additional method on Murtèl rock glacier and on the protalus rampart. Measurements of Rhizocarpon geographicum thalli revealed increasing sizes from the root zone of the rock glacier to its front. On the Murtèl rock glacier, Rhizocarpon geographicum thalli with a diameter >4cm occur on surfaces with ages between 5000 and 6000 years B.P.

The statistical analysis (MULVA-5) of the dense vegetation cover of the inactive and relict rock glaciers revealed four plant sociological groups, which are composed of species reflecting well consolidated sites: alpine grassland, subalpine dwarf shrubs and small patches with single small trees of Swiss stone pine (Pinus cembra) and larch (Larix decidua).     

Medical Team Evaluation: Effect on Emergency Department Waiting Time and Length of Stay

Emergency Departments (ED) are trying to alleviate crowding using various interventions. We assessed the effect of an alternative model of care, the Medical Team Evaluation (MTE) concept, encompassing team triage, quick registration, redesign of triage rooms and electronic medical records (EMR) on door-to-doctor (waiting) time and ED length of stay (LOS). We conducted an observational, before-and-after study at an urban academic tertiary care centre. On July 17^th 2014, MTE was initiated from 9:00 a.m. to 10 p.m., 7 days a week. A registered triage nurse was teamed with an additional senior ED physician. Data of the 5-month pre-MTE and the 5-month MTE period were analysed. A matched comparison of waiting times and ED LOS of discharged and admitted patients pertaining to various Emergency Severity Index (ESI) triage categories was performed based on propensity scores. With MTE, the median waiting times improved from 41.2 (24.8–66.6) to 10.2 (5.7–18.1) minutes (min; P < 0.01). Though being beneficial for all strata, the improvement was somewhat greater for discharged, than for admitted patients. With a reduction from 54.3 (34.2–84.7) to 10.5 (5.9–18.4) min (P < 0.01), in terms of waiting times, MTE was most advantageous for ESI4 patients. The overall median ED LOS increased for about 15 min (P < 0.01), increasing from 3.4 (2.1–5.3) to 3.7 (2.3–5.6) hours. A significant increase was observed for all the strata, except for ESI5 patients. Their median ED LOS dropped by 73% from 1.2 (0.8–1.8) to 0.3 (0.2–0.5) hours (P < 0.01). In the same period the total orders for diagnostic radiology increased by 1,178 (11%) from 10,924 to 12,102 orders, with more imaging tests being ordered for ESI 2, 3 and 4 patients. Despite improved waiting times a decrease of ED LOS was only seen in ESI level 5 patients, whereas in all the other strata ED LOS increased. We speculate that this was brought about by the tendency of triage physicians to order more diagnostic radiology, anticipating that it may be better for the downstream physician to have more information rather than less.     

The noncanonical type III secretion system of Xanthomonas translucens pv. graminis is essential for forage grass infection

Xanthomonas translucens pv. graminis (Xtg) is a gammaproteobacterium that causes bacterial wilt on a wide range of forage grasses. To gain insight into the host–pathogen interaction and to identify the virulence factors of Xtg, we compared a draft genome sequence of one isolate (Xtg29) with other Xanthomonas spp. with sequenced genomes. The type III secretion system (T3SS) encoding a protein transport system for type III effector (T3E) proteins represents one of the most important virulence factors of Xanthomonas spp. In contrast with other Xanthomonas spp. assigned to clade 1 on the basis of phylogenetic analyses, we identified an hrp (hypersensitive response and pathogenicity) gene cluster encoding T3SS components and a representative set of 35 genes encoding putative T3Es in the genome of Xtg29. The T3SS was shown to be divergent from the hrp gene clusters of other sequenced Xanthomonas spp. Xtg mutants deficient in T3SS regulating and structural genes were constructed to clarify the role of the T3SS in forage grass colonization. Italian ryegrass infection with these mutants led to significantly reduced symptoms (P < 0.05) relative to plants infected with the wild‐type strain. This showed that the T3SS is required for symptom evocation. In planta multiplication of the T3SS mutants was not impaired significantly relative to the wild‐type, indicating that the T3SS is not required for survival until 14 days post‐infection. This study represents the first major step to understanding the bacterial colonization strategies deployed by Xtg and may assist in the identification of resistance (R) genes in forage grasses.     

Branch mode selection during early lung development

Many organs of higher organisms, such as the vascular system, lung, kidney, pancreas, liver and glands, are heavily branched structures. The branching process during lung development has been studied in great detail and is remarkably stereotyped. The branched tree is generated by the sequential, non-random use of three geometrically simple modes of branching (domain branching, planar and orthogonal bifurcation). While many regulatory components and local interactions have been defined an integrated understanding of the regulatory network that controls the branching process is lacking. We have developed a deterministic, spatio-temporal differential-equation based model of the core signaling network that governs lung branching morphogenesis. The model focuses on the two key signaling factors that have been identified in experiments, fibroblast growth factor (FGF10) and sonic hedgehog (SHH) as well as the SHH receptor patched (Ptc). We show that the reported biochemical interactions give rise to a Schnakenberg-type Turing patterning mechanisms that allows us to reproduce experimental observations in wildtype and mutant mice. The kinetic parameters as well as the domain shape are based on experimental data where available. The developed model is robust to small absolute and large relative changes in the parameter values. At the same time there is a strong regulatory potential in that the switching between branching modes can be achieved by targeted changes in the parameter values. We note that the sequence of different branching events may also be the result of different growth speeds: fast growth triggers lateral branching while slow growth favours bifurcations in our model. We conclude that the FGF10-SHH-Ptc1 module is sufficient to generate pattern that correspond to the observed branching modes.     

Myeloid lineage cell-restricted insulin resistance protects apolipoproteinE-deficient mice against atherosclerosis

Inflammatory processes play an important role in the pathogenesis of vascular diseases, and insulin-resistant diabetes mellitus type 2 represents an important risk factor for the development of atherosclerosis. To directly address the role of insulin resistance in myeloid lineage cells in the development of atherosclerosis, we have created mice with myeloid lineage-specific inactivation of the insulin receptor gene. On an ApoE-deficient background, MphIRKO mice developed smaller atherosclerotic lesions. There was a dramatic decrease in LPS-stimulated IL-6 and IL-1beta expression in the presence of macrophage autonomous insulin resistance. Consistently, while insulin-resistant IRS-2-deficient mice on an ApoE-deficient background display aggravated atherosclerosis, fetal liver cell transplantation of IRS-2(-/-) ApoE(-/-) cells ameliorated atherosclerosis in Apo-E-deficient mice. Thus, systemic versus myeloid cell-restricted insulin resistance has opposing effects on the development of atherosclerosis, providing direct evidence that myeloid lineage autonomous insulin signaling provides proinflammatory signals predisposing to the development of atherosclerosis.     

Insulin-like growth factor-1 controls type 2 T cell-independent B cell response

The IGF-1 receptor (IGF-1R) is expressed on T and B lymphocytes, and the expression of the insulin- and IGF-1-signaling machinery undergoes defined changes throughout lineage differentiation, offering a putative role for IGF-1 in the regulation of immune responses. To study the role of the IGF-1R in lymphocyte differentiation and function in vivo, we have reconstituted immunodeficient RAG2-deficient mice with IGF-1R(-/-) fetal liver cells. Despite the absence of IGF-1Rs, the development and ex vivo activation of B and T lymphocytes were unaltered in these chimeric mice. By contrast, the humoral immune response to the T cell-independent type 2 Ag 4-hydroxy-3-nitrophenyl acetyl-Ficoll was significantly reduced in mice reconstituted with IGF-1R-deficient fetal liver cells, whereas responses to the T cell-dependent Ag 4-hydroxy-3-nitrophenyl acetyl-chicken globulin were normal. Moreover, in an in vitro model of T cell-independent type 2 responses, IGF-1 promoted Ig production potently upon polyvalent membrane-IgD cross-linking. These data indicate that functional IGF-1R signaling is required for T cell-independent B cell responses in vivo, defining a novel regulatory mechanism for the immune response against bacterial polysaccharides.     

Investigations of oxygen transfer into Penicillium chrysogenum pellets by microprobe measurements

A microcoaxial needle sensor with a tip diameter of ca. 0.7 mum was used as a microprobe to measure profiles of dissolved oxygen tension (DOT) within fixed pellets of Penicillium chrysogenum as a function of the DOT level around the pellet, in the presence and absence of bulk convective flow and turbulence. The investigations indicate that the oxygen transfer mechanism is complex. The results were interpreted by assuming the penetration convective flow into the entire pellet and penetration of turbulence into the outer range. A model was developed which was able to describe the measured DOT profiles very well. The model takes into account molecular and turbulent diffusion as well as convective flow as transfer mechanisms inside of the pellet. Structures of pellets used for microprobe measurements were evaluated by histological investigations. Considerable variations of mycelial density with radius within the pellets were found.