Opilionids in the diet of bird nestlings

Untersuchungen über die Ernährung der Vögel sind ein traditionelles Arbeitsgebiet der Ornithologie (EMMRICH 1973). Spezielle Arbeiten zur Bedeutung von Spinnentieren (Arachnida) und ihrem Vorkommen in der Vogelnahrung sind aber selten. Gerade Angaben über Weberknechte verbergen sich oft unter dem Namen Arachnida (z. B. PFEIFER & KEJL 1958), selten ist die Ordnung Opiliones konkret angeführt (z. B. DORNBUSCH 1981, EMMRICH 1973, KRISTIN 1992). BURES (1986) erwähnt immerhin die gefundenen Gattungen. Das Spektrum der gefundenen Weberknechtarten geben nur wenige Autoren an (z. B. SACHER & DORNBUSCH 1990). Im Zuge eines Forschungsprojekts zur Ernährung von Vogelnestlingen in Wäldern und Hecken (z. B. KRISTIN 1992, 1993) konnten auch Daten über Weberknechte in der Nestlingsnahrung gesammelt werden. Sie sollen im Folgenden kurz dargestellt werden

Advancing Knowledge on Situation Comprehension in Dynamic Traffic Situations by Studying Eye Movements to Empty Spatial Locations

Objective: This study used the looking-at-nothing phenomenon to explore situation awareness (SA) and the effects of working memory (WM) load in driving situations. Background: While driving, people develop a mental representation of the environment. Since errors in retrieving information from this representation can have fatal consequences, it is essential for road safety to investigate this process. During retrieval, people tend to fixate spatial positions of visually encoded information, even if it is no longer available at that location. Previous research has shown that this "looking-at-nothing" behavior can be used to trace retrieval processes. Method: In a video-based laboratory experiment with 2 (WM) x 3 (SA level) within-subjects design, participants (N = 33) viewed a reduced screen and evaluated auditory statements relating to different SA levels on previously seen dynamic traffic scenarios while eye movements were recorded. Results: When retrieving information, subjects more frequently fixated emptied spatial locations associated with the information relevant for the probed SA level. The retrieval of anticipations (SA level 3) in contrast to the other SA level information resulted in more frequent gaze transitions that corresponded to the spatial dynamics of future driving behavior. Conclusion: The results support the idea that people build a visual-spatial mental image of a driving situation. Different gaze patterns when retrieving level-specific information indicate divergent retrieval processes. Application: Potential applications include developing new methodologies to assess the mental representation and SA of drivers objectively

Protein trafficking, ergosterol biosynthesis and membrane physics impact recombinant protein secretion in Pichia pastoris

Background: The increasing availability of 'omics' databases provide important platforms for yeast engineering strategies since they offer a lot of information on the physiology of the cells under diverse growth conditions, including environmental stresses. Notably, only a few of these approaches have considered a performance under recombinant protein production conditions. Recently, we have identified a beneficial effect of low oxygen availability on the expression of a human Fab fragment in Pichia pastoris. Transcriptional analysis and data mining allowed for the selection of potential targets for strain improvement. A first selection of these candidates has been evaluated as recombinant protein secretion enhancers. Results: Based on previous transcriptomics analyses, we selected 8 genes for co-expression in the P. pastoris strain already secreting a recombinant Fab fragment. Notably, WSC4 (which is involved in trafficking through the ER) has been identified as a novel potential target gene for strain improvement, with up to a 1.2-fold increase of product yield in shake flask cultures. A further transcriptomics-based strategy to modify the yeast secretion system was focused on the ergosterol pathway, an aerobic process strongly affected by oxygen depletion. By specifically partially inhibiting ergosterol synthesis with the antifungal agent fluconazole (inhibiting Erg11p), we tried to mimic the hypoxic conditions, in which the cellular ergosterol content was significantly decreased. This strategy led to an improved Fab yield (2-fold) without impairing cellular growth. Since ergosterol shortage provokes alterations in the plasma membrane composition, an important role of this cellular structure in protein secretion is suggested. This hypothesis was additionally supported by the fact that the addition of non-ionic surfactants also enhanced Fab secretion. Conclusions: The current study presents a systems biotechnology-based strategy for the engineering of the industrially important yeast P. pastoris combining the use of host specific DNA microarray technologies and physiological studies under well defined environmental conditions. Such studies allowed for the identification of novel targets related with protein trafficking and ergosterol biosynthesis for improved recombinant protein production. Nevertheless, further studies will be required to elucidate the precise mechanisms whereby membrane biogenesis and composition impact on protein secretion in P. pastoris

Targeting the Immunomodulatory Capacity of MDS MSCs by Tasquinimod

Myelodysplastic syndromes (MDS) belong to the most common hematological neoplasms in the elderly population, characterized by ineffective hematopoiesis, peripheral cytopenia and the risk of transformation into acute myeloid leukemia. A dysregulated innate immune response and pro-inflammatory bone marrow microenvironment play a crucial role in the MDS pathogenesis by providing chronic inflammation which makes those pathways the perfect candidate for future therapeutics. Specifically, it has been shown that the alarmin S100A9, an important ligand for dri-ving inflammation and promoting tumor progression, is elevated in MDS patients. Previous expe-riments performed in the Stem Cell Lab 2 provided evidence that mesenchymal stromal cells (MSCs), an important component of the BM niche with immunomodulatory capacity, can be tar-geted by the novel oral small molecular drug Tasquinimod (TASQ, Active Biotech) which has demonstrated S100A9 inhibitory activity. The inhibition of inflammation-related molecules such as IL-1b, IL-18, PD-L1, resulted in a significant improvement of the hematopoietic support by MSCs. However, almost nothing is known about potential effects of TASQ in the context of immunomo-dulation. Therefore, we aimed in this project to understand the mechanisms of S100A9+/- TASQ concerning the immunomodulatory capacity of MDS-MSCs in response to T cell-mediated in-flammation by analyzing adhesion (ICAM1, VCAM1), immune checkpoint (PDL1, PDL2), anti-inflammatory cytokine (COX2, IDO1), chemokines (CCL2, IL8) and extracellular matrix-related (COL4A2, COL1A1) gene expression with quantitative real-time PCR. We observed a general de-crease in the aforementioned genes except for COL4A2 and COL1A1 upon treatment with TASQ, though T cell-mediated inflammation and activity remained unaffected, suggesting that inhibition of S100A9 reduces the inflammation-mediated immunomodulatory potential of MDS-MSCs.:Motivation Aim Methods Result Conclusio

Lake Site Assessments: US EPA TIME-New England Lakes

TIME (Temporally Integrated Monitoring of Ecosystems) is a statistically selected population of lakes in New Eng- land and the Hudson Valley (31 lakes) and the Adirondacks (43 lakes) that were selected from the original 1991 EMAP-SW (Environmental Monitoring and Assessment Program–Surface Waters) population with acid neutralizing capacity less than 100 meq/L (Young & Stoddard 1996). Samples are taken annually, during a summer base-flow ‘index period’. This sampling strategy is used to reduce hydrologic impact on water chemistry and hence provide an assessment of trends in chemistry with the least number of samples (e.g., Stoddard et al. 2003). The EMAP program sampled these lakes and many others one or more times between 1991-1994. As part of EMAP, the lakes were characterized with respect to landscape features, hydrology, geology, and chemistry as well as biological studies (fish, breeding birds, zooplankton) and a paleo-limnological coring study to reconstruct pH and other variables. The program was discontinued, but some sampling of the lakes continued through other funding sources during the hiatus. In 1999, the TIME project officially began, with a goal of assessing the effectiveness of the Clean Air Act Amendments of 1990 at reducing acidification of surface waters (Stoddard et al. 2003, Kahl et al. 2004). As of this writing, the lakes have records spanning two decades or more

Dynamic Connectivity in Disk Graphs

Let S ⊆ R2 be a set of n sites in the plane, so that every site s ∈ S has an associated radius rs > 0. Let D(S) be the disk intersection graph defined by S, i.e., the graph with vertex set S and an edge between two distinct sites s, t ∈ S if and only if the disks with centers s, t and radii rs , rt intersect. Our goal is to design data structures that maintain the connectivity structure of D(S) as sites are inserted and/or deleted in S. First, we consider unit disk graphs, i.e., we fix rs = 1, for all sites s ∈ S. For this case, we describe a data structure that has O(log2 n) amortized update time and O(log n/ log log n) query time. Second, we look at disk graphs with bounded radius ratio Ψ, i.e., for all s ∈ S, we have 1 ≤ rs ≤ Ψ, for a parameter Ψ that is known in advance. Here, we not only investigate the fully dynamic case, but also the incremental and the decremental scenario, where only insertions or only deletions of sites are allowed. In the fully dynamic case, we achieve amortized expected update time O(Ψ log4 n) and query time O(log n/ log log n). This improves the currently best update time by a factor of Ψ. In the incremental case, we achieve logarithmic dependency on Ψ, with a data structure that has O(α(n)) amortized query time and O(log Ψ log4 n) amortized expected update time, where α(n) denotes the inverse Ackermann function. For the decremental setting, we first develop an efficient decremental disk revealing data structure: given two sets R and B of disks in the plane, we can delete disks from B, and upon each deletion, we receive a list of all disks in R that no longer intersect the union of B. Using this data structure, we get decremental data structures with a query time of O(log n/ log log n) that supports deletions in O(n log Ψ log4 n) overall expected time for disk graphs with bounded radius ratio Ψ and O(n log5 n) overall expected time for disk graphs with arbitrary radii, assuming that the deletion sequence is oblivious of the internal random choices of the data structures

Macromolecular and elemental composition analysis and extracellular metabolite balances of Pichia pastoris growing at different oxygen levels

Background: Analysis of the cell operation at the metabolic level requires collecting data of different types and to determine their confidence level. In addition, the acquired information has to be combined in order to obtain a consistent operational view. In the case of Pichia pastoris, information of its biomass composition at macromolecular and elemental level is scarce particularly when different environmental conditions, such as oxygen availability or, genetic backgrounds (e.g. recombinant protein production vs. non production conditions) are compared. Results: P. pastoris cells growing in carbon-limited chemostat cultures under different oxygenation conditions (% O2 in the bioreactor inlet gas: 21%, 11% and 8%, corresponding to normoxic, oxygen-limiting and hypoxic conditions, respectively), as well as under recombinant protein (antibody fragment, Fab) producing and non-producing conditions, were analyzed from different points of view. On the one hand, the macromolecular and elemental composition of the biomass was measured using different techniques at the different experimental conditions and proper reconciliation techniques were applied for gross error detection of the measured substrates and products conversion rates. On the other hand, fermentation data was analyzed applying elemental mass balances. This allowed detecting a previously missed by-product secreted under hypoxic conditions, identified as arabinitol (aka. arabitol). After identification of this C5 sugar alcohol as a fermentation by-product, the mass balances of the fermentation experiments were validated. Conclusions: After application of a range of analytical and statistical techniques, a consistent view of growth parameters and compositional data of P. pastoris cells growing under different oxygenation conditions was obtained. The obtained data provides a first view of the effects of oxygen limitation on the physiology of this microorganism, while recombinant Fab production seems to have little or no impact at this level of analysis. Furthermore, the results will be highly useful in other complementary quantitative studies of P. pastoris physiology, such as metabolic flux analysis

HAMLET Interacts with Lipid Membranes and Perturbs Their Structure and Integrity

Background Cell membrane interactions rely on lipid bilayer constituents and molecules inserted within the membrane, including specific receptors. HAMLET (human α-lactalbumin made lethal to tumor cells) is a tumoricidal complex of partially unfolded α-lactalbumin (HLA) and oleic acid that is internalized by tumor cells, suggesting that interactions with the phospholipid bilayer and/or specific receptors may be essential for the tumoricidal effect. This study examined whether HAMLET interacts with artificial membranes and alters membrane structure. Methodology/Principal Findings We show by surface plasmon resonance that HAMLET binds with high affinity to surface adherent, unilamellar vesicles of lipids with varying acyl chain composition and net charge. Fluorescence imaging revealed that HAMLET accumulates in membranes of vesicles and perturbs their structure, resulting in increased membrane fluidity. Furthermore, HAMLET disrupted membrane integrity at neutral pH and physiological conditions, as shown by fluorophore leakage experiments. These effects did not occur with either native HLA or a constitutively unfolded Cys-Ala HLA mutant (rHLAall-Ala). HAMLET also bound to plasma membrane vesicles formed from intact tumor cells, with accumulation in certain membrane areas, but the complex was not internalized by these vesicles or by the synthetic membrane vesicles. Conclusions/Significance The results illustrate the difference in membrane affinity between the fatty acid bound and fatty acid free forms of partially unfolded HLA and suggest that HAMLET engages membranes by a mechanism requiring both the protein and the fatty acid. Furthermore, HAMLET binding alters the morphology of the membrane and compromises its integrity, suggesting that membrane perturbation could be an initial step in inducing cell death

A multi-level study of recombinant Pichia pastoris in different oxygen conditions

Background: Yeasts are attractive expression platforms for many recombinant proteins, and there is evidence for an important interrelation between the protein secretion machinery and environmental stresses. While adaptive responses to such stresses are extensively studied in Saccharomyces cerevisiae, little is known about their impact on the physiology of Pichia pastoris. We have recently reported a beneficial effect of hypoxia on recombinant Fab secretion in P. pastoris chemostat cultivations. As a consequence, a systems biology approach was used to comprehensively identify cellular adaptations to low oxygen availability and the additional burden of protein production. Gene expression profiling was combined with proteomic analyses and the 13C isotope labelling based experimental determination of metabolic fluxes in the central carbon metabolism. Results: The physiological adaptation of P. pastoris to hypoxia showed distinct traits in relation to the model yeast S. cerevisiae. There was a positive correlation between the transcriptomic, proteomic and metabolic fluxes adaptation of P. pastoris core metabolism to hypoxia, yielding clear evidence of a strong transcriptional regulation component of key pathways such as glycolysis, pentose phosphate pathway and TCA cycle. In addition, the adaptation to reduced oxygen revealed important changes in lipid metabolism, stress responses, as well as protein folding and trafficking. Conclusions: This systems level study helped to understand the physiological adaptations of cellular mechanisms to low oxygen availability in a recombinant P. pastoris strain. Remarkably, the integration of data from three different levels allowed for the identification of differences in the regulation of the core metabolism between P. pastoris and S. cerevisiae. Detailed comparative analysis of the transcriptomic data also led to new insights into the gene expression profiles of several cellular processes that are not only susceptible to low oxygen concentrations, but might also contribute to enhanced protein secretion

Protein folding and conformational stress in microbial cells producing recombinant proteins : a host comparative overview

Different species of microorganisms including yeasts, filamentous fungi and bacteria have been used in the past 25 years for the controlled production of foreign proteins of scientific, pharmacological or industrial interest. A major obstacle for protein production processes and a limit to overall success has been the abundance of misfolded polypeptides, which fail to reach their native conformation. The presence of misfolded or folding-reluctant protein species causes considerable stress in host cells. The characterization of such adverse conditions and the elicited cell responses have permitted to better understand the physiology and molecular biology of conformational stress. Therefore, microbial cell factories for recombinant protein production are depicted here as a source of knowledge that has considerably helped to picture the extremely rich landscape of in vivo protein folding, and the main cellular players of this complex process are described for the most important cell factories used for biotechnological purposes