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The acinar salivary gland of the cockroach, Periplaneta americana, is innervated by dopaminergic and serotonergic nerve fibers. Stimulation of the glands by serotonin (5-hydroxytryptamine, 5-HT) results in the production of a protein-rich saliva, whereas stimulation by dopamine results in saliva that is protein-free. Thus, dopamine acts selectively on ion-transporting peripheral cells within the acini, and 5-HT acts on protein-producing central cells. We have investigated the pharmacology of the 5-HT-induced secretory activity of isolated salivary glands of P. americana by testing several 5-HT receptor agonists and antagonists. The effects of 5-HT can be mimicked by the non-selective 5-HT receptor agonist 5-methoxytryptamine. All tested agonists that display at least some receptor subtype specificity in mammals, i.e., 5-carboxamidotryptamine, (+/-)-8-OH-DPAT, (+/-)-DOI, and AS 19, were ineffective in stimulating salivary secretion. 5-HT-induced secretion can be blocked by the vertebrate 5-HT receptor antagonists methiothepin, cyproheptadine, and mianserin. Our pharmacological data indicate that the pharmacology of arthropod 5-HT receptors is remarkably different from that of their vertebrate counterparts. (C) 2007 Elsevier Ltd. All rights reserved.
The vacuolar H+-ATPase (V-ATPase) in the apical membrane of blowfly (Calliphora vicina) salivary gland cells energizes the secretion of a KCl-rich saliva in response to the neurohormone serotonin (5-HT). We have shown previously that exposure to 5-HT induces a cAMP-mediated reversible assembly of V-0 and V-1 subcomplexes to V-ATPase holoenzymes and increases V-ATPase-driven proton transport. Here, we analyze whether the effect of cAMP on V-ATPase is mediated by protein kinase A (PKA) or exchange protein directly activated by cAMP (Epac), the cAMP target proteins that are present within the salivary glands. Immunofluorescence microscopy shows that PKA activators, but not Epac activators, induce the translocation of V1 components from the cytoplasm to the apical membrane, indicative of an assembly of V-ATPase holoenzymes. Measurements of transepithelial voltage changes and microfluorometric pH measurements at the luminal surface of cells in isolated glands demonstrate further that PKA-activating cAMP analogs increase cation transport to the gland lumen and induce a V-ATPase-dependent luminal acidification, whereas activators of Epac do not. Inhibitors of PKA block the 5-HT-induced V-1 translocation to the apical membrane and the increase in proton transport. We conclude that cAMP exerts its effects on V-ATPase via PKA.
A production study is presented that investigates the effects of word order and information structural context on the prosodic realization of declarative sentences in Hindi. Previous work on Hindi intonation has shown that: (i) non-final content words bear rising pitch accents (Moore 1965, Dyrud 2001, Nair 1999); (ii) focused constituents show greater pitch excursion and longer duration and that post-focal material undergoes pitch range reduction (Moore 1965, Harnsberger 1994, Harnsberger and Judge 1996); and (iii) focused constituents may be followed by a phrase break (Moore 1965). By means of a controlled experiment, we investigated the effect of focus in relation to word order variation using 1200 utterances produced by 20 speakers. Fundamental frequency (F0) and duration of constituents were measured in Subject-Object-Verb (SOV) and Object-Subject-Verb (OSV) sentences in different information structural conditions (wide focus, subject focus and object focus). The analyses indicate that (i) regardless of word order and focus, the constituents are in a strict downstep relationship; (ii) focus is mainly characterized by post-focal pitch range reduction rather than pitch raising of the element in focus; (iii) given expressions that occur pre-focally appear to undergo no reduction; (iv) pitch excursion and duration of the constituents is higher in OSV compared to SOV sentences. A phonological analysis suggests that focus affects pitch scaling and that word order influences prosodic phrasing of the constituents.
Biogenic amines are important messenger substances in the central nervous system and in peripheral organs of vertebrates and of invertebrates. The honeybee, Apis mellifera, is excellently suited to uncover the functions of biogenic amines in behaviour, because it has an extensive behavioural repertoire, with a number of biogenic amine receptors characterised in this insect. In the honeybee, the biogenic amines dopamine, octopamine, serotonin and tyramine modulate neuronal functions in various ways. Dopamine and serotonin are present in high concentrations in the bee brain, whereas octopamine and tyramine are less abundant. Octopamine is a key molecule for the control of honeybee behaviour. It generally has an arousing effect and leads to higher sensitivity for sensory inputs, better learning performance and increased foraging behaviour. Tyramine has been suggested to act antagonistically to octopamine, but only few experimental data are available for this amine. Dopamine and serotonin often have antagonistic or inhibitory effects as compared to octopamine. Biogenic amines bind to membrane receptors that primarily belong to the large gene-family of GTP-binding (G) protein coupled receptors. Receptor activation leads to transient changes in concentrations of intracellular second messengers such as cAMP, IP3 and/or Ca2+. Although several biogenic amine receptors from the honeybee have been cloned and characterised more recently, many genes still remain to be identified. The availability of the completely sequenced genome of Apis mellifera will contribute substantially to closing this gap. In this review, we will discuss the present knowledge on how biogenic amines and their receptor-mediated cellular responses modulate different behaviours of honeybees including learning processes and division of labour.
The influence of information structure on tonal scaling in German is examined experimentally. Eighteen speakers uttered a total of 2277 sentences of the same syntactic structure, but with a varying number of constituents, word order and focus-given structure. The quantified results for German support findings for other Germanic languages that the scaling of high tones, and thus the entire melodic pattern, is influenced by information structure. Narrow focus raised the high tones of pitch accents, while givenness lowered them in prenuclear position and canceled them out postnuclearly. The effects of focus and givenness are calculated against all-new sentences as a baseline, which we expected to be characterized by downstep, a significantly lower scaling of high tones as compared to declination. The results further show that information structure alone cannot account for all variations. We therefore assume that dissimilatory tonal effects play a crucial role in the tonal scaling of German. The effects consist of final f0 drop, a steep fall from a raised high tone to the bottom line of the speaker, H-raising before a low tone, and H-lowering before a raised high tone. No correlation between word order and tone scaling could be established. 2008 Elsevier Ltd. All rights reserved.
Questions: 1. Are there differences among species in their preference for coniferous vs. deciduous forest? 2. Are tree and shrub species better colonizers of recent forest stands than herbaceous species? 3. Do colonization patterns of plant species groups depend on tree species composition? Location: Three deciduous and one coniferous recent forest areas in Brandenburg, NE Germany. Methods: In 34 and 21 transects in coniferous and deciduous stands, respectively, we studied the occurrence and percentage cover of vascular plants in a total of 150 plots in ancient stands, 315 in recent stands and 55 at the ecotone. Habitat preference, diaspore weight, generative dispersal potential and clonal extension were used to explain mechanisms of local migration. Regression analysis was conducted to test whether migration distance was related to species’ life-history traits. Results: 25 species were significantly associated with ancient stands and ten species were significantly more frequent in recent stands. Tree and shrub species were good colonizers of recent coniferous and deciduous stands. In the coniferous stands, all herbaceous species showed a strong dispersal limitation during colonization, whereas in the deciduous stands generalist species may have survived in the grasslands which were present prior to afforestation. Conclusions: The fast colonization of recent stands by trees and shrubs can be explained by their effective dispersal via wind and animals. This, and the comparably efficient migration of herbaceous forest specialists into recent coniferous stands, implies that the conversion of coniferous into deciduous stands adjacent to ancient deciduous forests is promising even without planting of trees.
Many cellular processes require decision making mechanisms, which must act reliably even in the unavoidable presence of substantial amounts of noise. However, the multistable genetic switches that underlie most decision-making processes are dominated by fluctuations that can induce random jumps between alternative cellular states. Here we show, via theoretical modeling of a population of noise-driven bistable genetic switches, that reliable timing of decision-making processes can be accomplished for large enough population sizes, as long as cells are globally coupled by chemical means. In the light of these results, we conjecture that cell proliferation, in the presence of cell-cell communication, could provide a mechanism for reliable decision making in the presence of noise, by triggering cellular transitions only when the whole cell population reaches a certain size. In other words , the summation performed by the cell population would average out the noise and reduce its detrimental impact.
Background: Biological systems adapt to changing environments by reorganizing their cellula r and physiological program with metabolites representing one important response level. Different stresses lead to both conserved and specific responses on the metabolite level which should be reflected in the underl ying metabolic network. Methodology/Principal Findings: Starting from experimental data obtained by a GC-MS based high-throughput metabolic profiling technology we here develop an approach that: (1) extracts network representations from metabolic conditiondependent data by using pairwise correlations, (2) determines the sets of stable and condition-dependent correlations based on a combination of statistical significance and homogeneity tests, and (3) can identify metabolites related to the stress response, which goes beyond simple ob servation s about the changes of metabolic concentrations. The approach was tested with Escherichia colias a model organism observed under four different environmental stress conditions (cold stress, heat stress, oxidative stress, lactose diau xie) and control unperturbed conditions. By constructing the stable network component, which displays a scale free topology and small-world characteristics, we demonstrated that: (1) metabolite hubs in this reconstructed correlation networks are significantly enriched for those contained in biochemical networks such as EcoCyc, (2) particular components of the stable network are enriched for functionally related biochemical path ways, and (3) ind ependently of the response scale, based on their importance in the reorganization of the cor relation network a set of metabolites can be identified which represent hypothetical candidates for adjusting to a stress-specific response. Conclusions/Significance: Network-based tools allowed the identification of stress-dependent and general metabolic correlation networks. This correlation-network-ba sed approach does not rely on major changes in concentration to identify metabolites important for st ress adaptation, but rather on the changes in network properties with respect to metabolites. This should represent a useful complementary technique in addition to more classical approaches.
Rain fall-runoff response in temperate humid headwater catchments is mainly controlled by hydrolo gical processes at the hillslope scale. Applied tracer experiments with fluore scent dye and salt tracers are well known tools in groundwater studies at the large scale and vadose zone studies at the plot scale, where they provide a means to characterise subsurface flow. We extend this approach to the hillslope scale to investigate saturated and unsaturated flow path s concertedly at a forested hill slope in the Austrian Alps. Dye staining experiments at the plot scale revealed that crack s and soil pipe s function as preferential flow path s in the fine-textured soils of the study area, and these preferenti al flow structures were active in fast subsurface transport of tracers at the hillslope scale. Breakthrough curves obtained under steady flow conditions could be fitted well to a one-dimensional convection-dispersion model. Under natural rain fall a positive correlation of tracer concentrations to the transient flows was observed. The results of this study demon strate qualitative and quantitative effects of preferential flow feature s on subsurface stormflow in a temperate humid headwater catchment. It turn s out that , at the hill slope scale, the interaction s of structures and processes are intrinsically complex, which implies that attempts to model such a hillslope satisfactorily require detailed investigation s of effective structures and parameters at the scale of interest.
Normal aging is associated with a decline in different cognitive domains and local structural atrophy as well as decreases in dopamine concentration and receptor density. To date, it is largely unknown how these reductions in dopaminergic neurotransmission affect human brain regions responsible for reward-based decision making in older adults. Using a learning criterion in a probabilistic object reversal task, we found a learning stage by age interaction in the dorsolateral prefrontal cortex (dIPFC) during decision making. While young adults recruited the dlPFC in an early stage of learning reward associations, older adults recruited the dlPFC when reward associations had already been learned. Furthermore, we found a reduced change in ventral striatal BOLD signal in older as compared to younger adults in response to high probability rewards. Our data are in line with behavioral evidence that older adults show altered stimulus-reward learning and support the view of an altered fronto-striatal interaction during reward-based decision making in old age, which contributes to prolonged learning of reward associations.
The study of non-coding RNA genes has received increased attention in recent years fuelled by accumulating evidence that larger portions of genomes than previously acknowledged are transcribed into RNA molecules of mostly unknown function, as well as the discovery of novel non-coding RNA types and functional RNA elements. Here, we demonstrate that specific properties of graphs that represent the predicted RNA secondary structure reflect functional information. We introduce a computational algorithm and an associated web-based tool (GraPPLE) for classifying non-coding RNA molecules as functional and, furthermore, into Rfam families based on their graph properties. Unlike sequence-similarity-based methods and covariance models, GraPPLE is demonstrated to be more robust with regard to increasing sequence divergence, and when combined with existing methods, leads to a significant improvement of prediction accuracy. Furthermore, graph properties identified as most informative are shown to provide an understanding as to what particular structural features render RNA molecules functional. Thus, GraPPLE may offer a valuable computational filtering tool to identify potentially interesting RNA molecules among large candidate datasets.
A macro-tidal freshwater ecosystem recovering from hypereutrophication : the Schelde lease study
(2009)
We report a 40 year record of eutrophication and hypoxia on an estuarine ecosystem and its recovery from hypereutrophication. After decades of high inorganic nutrient concentrations and recurring anoxia and hypoxia, we observe a paradoxical increase in chlorophyll-a concentrations with decreasing nutrient inputs. We hypothesise that algal growth was inhibited due to hypereutrophication, either by elevated ammonium concentrations, severe hypoxia or the production of harmful substances in such a reduced environment. We study the dynamics of a simple but realistic mathematical model, incorporating the assumption of algal growth inhibition. It shows a high algal biomass, net oxygen production equilibrium with low ammonia inputs, and a low algal biomass, net oxygen consumption equilibrium with high ammonia inputs. At intermediate ammonia inputs it displays two alternative stable states. Although not intentional, the numerical output of this model corresponds to observations, giving extra support for assumption of algal growth inhibition. Due to potential algal growth inhibition, the recovery of hypereutrophied systems towards a classical eutrophied state, will need reduction of waste loads below certain thresholds and will be accompanied by large fluctuations in oxygen concentrations. We conclude that also flow-through systems, heavily influenced by external forcings which partly mask internal system dynamics, can display multiple stable states.
Background: Multidirectional interactions in social networks can have a profound effect on mate choice behavior; e.g., Poecilia mexicana males show weaker expression of mating preferences when being observed by a rival. This may be an adaptation to reduce sperm competition risk, which arises because commonly preferred female phenotypes will receive attention also from surrounding males, and/or because other males can copy the focal male's mate choice. Do P. mexicana males indeed respond to perceived sperm competition risk? We gave males a choice between two females and repeated the tests under one of the following conditions: (1) an empty transparent cylinder was presented (control); (2) another ("audience") male inside the cylinder observed the focal male throughout the 2nd part, or (3) the audience male was presented only before the tests, but could not eavesdrop during the actual choice tests (non-specific sperm competition risk treatments); (4) the focal male could see a rival male interact sexually with the previously preferred, or (5) with the non-preferred female before the 2nd part of the tests (specific sperm competition risk treatments). Results: The strength of individual male preferences declined slightly also during the control treatment (1). However, this decrease was more than two-fold stronger in audience treatment (2), i.e., with non-specific sperm competition risk including the possibility for visual eavesdropping by the audience male. No audience effect was found in treatments (3) and (5), but a weak effect was also observed when the focal male had seen the previously preferred female sexually interact with a rival male (treatment 4; specific sperm competition risk). Conclusion: When comparing the two 'non-specific sperm competition risk' treatments, a very strong effect was found only when the audience male could actually observe the focal male during mate choice [treatment (2)]. This suggests that focal males indeed attempt to conceal their mating preferences so as to prevent surrounding males from copying their mate choice. When there is no potential for eavesdropping [treatment (3)], non-specific specific sperm competition risk seems to play a minor or no role. Our results also show that P. mexicana males tend to share their mating effort more equally among females when the resource value of their previously preferred mate decreases after mating with a rival male (perceived specific sperm competition risk), but this effect is comparatively weak.
Background: Hybrids represent a cornerstone in the success story of breeding programs. The fundamental principle underlying this success is the phenomenon of hybrid vigour, or heterosis. It describes an advantage of the offspring as compared to the two parental lines with respect to parameters such as growth and resistance against abiotic or biotic stress. Dominance, overdominance or epistasis based models are commonly used explanations. Conclusion/Significance: The heterosis level is clearly a function of the combination of the parents used for offspring production. This results in a major challenge for plant breeders, as usually several thousand combinations of parents have to be tested for identifying the best combinations. Thus, any approach to reliably predict heterosis levels based on properties of the parental lines would be highly beneficial for plant breeding. Methodology/Principal Findings: Recently, genetic data have been used to predict heterosis. Here we show that a combination of parental genetic and metabolic markers, identified via feature selection and minimum-description-length based regression methods, significantly improves the prediction of biomass heterosis in resulting offspring. These findings will help furthering our understanding of the molecular basis of heterosis, revealing, for instance, the presence of nonlinear genotype-phenotype relationships. In addition, we describe a possible approach for accelerated selection in plant breeding.
Background: Phosphorylation of proteins plays a crucial role in the regulation and activation of metabolic and signaling pathways and constitutes an important target for pharmaceutical intervention. Central to the phosphorylation process is the recognition of specific target sites by protein kinases followed by the covalent attachment of phosphate groups to the amino acids serine, threonine, or tyrosine. The experimental identification as well as computational prediction of phosphorylation sites (P-sites) has proved to be a challenging problem. Computational methods have focused primarily on extracting predictive features from the local, one-dimensional sequence information surrounding phosphorylation sites. Results: We characterized the spatial context of phosphorylation sites and assessed its usability for improved phosphorylation site predictions. We identified 750 non-redundant, experimentally verified sites with three-dimensional (3D) structural information available in the protein data bank (PDB) and grouped them according to their respective kinase family. We studied the spatial distribution of amino acids around phosphorserines, phosphothreonines, and phosphotyrosines to extract signature 3D-profiles. Characteristic spatial distributions of amino acid residue types around phosphorylation sites were indeed discernable, especially when kinase-family-specific target sites were analyzed. To test the added value of using spatial information for the computational prediction of phosphorylation sites, Support Vector Machines were applied using both sequence as well as structural information. When compared to sequence-only based prediction methods, a small but consistent performance improvement was obtained when the prediction was informed by 3D-context information. Conclusion: While local one-dimensional amino acid sequence information was observed to harbor most of the discriminatory power, spatial context information was identified as relevant for the recognition of kinases and their cognate target sites and can be used for an improved prediction of phosphorylation sites. A web-based service (Phos3D) implementing the developed structurebased P-site prediction method has been made available at http://phos3d.mpimp-golm.mpg.de.
The temporal dynamics of hydrological model performance gives insights into errors that cannot be obtained from global performance measures assigning a single number to the fit of a simulated time series to an observed reference series. These errors can include errors in data, model parameters, or model structure. Dealing with a set of performance measures evaluated at a high temporal resolution implies analyzing and interpreting a high dimensional data set. This paper presents a method for such a hydrological model performance assessment with a high temporal resolution and illustrates its application for two very different rainfall-runoff modeling case studies. The first is the Wilde Weisseritz case study, a headwater catchment in the eastern Ore Mountains, simulated with the conceptual model WaSiM-ETH. The second is the Malalcahuello case study, a headwater catchment in the Chilean Andes, simulated with the physicsbased model Catflow. The proposed time-resolved performance assessment starts with the computation of a large set of classically used performance measures for a moving window. The key of the developed approach is a data-reduction method based on self-organizing maps (SOMs) and cluster analysis to classify the high-dimensional performance matrix. Synthetic peak errors are used to interpret the resulting error classes. The final outcome of the proposed method is a time series of the occurrence of dominant error types. For the two case studies analyzed here, 6 such error types have been identified. They show clear temporal patterns, which can lead to the identification of model structural errors.
Background: The EXO (EXORDIUM) gene was identified as a potential mediator of brassinosteroid (BR)-promoted growth. It is part of a gene family with eight members in Arabidopsis. EXO gene expression is under control of BR, and EXO overexpression promotes shoot and root growth. In this study, the consequences of loss of EXO function are described. Results: The exo loss of function mutant showed diminished leaf and root growth and reduced biomass production. Light and scanning electron microscopy analyses revealed that impaired leaf growth is due to reduced cell expansion. Epidermis, palisade, and spongy parenchyma cells were smaller in comparison to the wild-type. The exo mutant showed reduced brassinolide-induced cotyledon and hypocotyl growth. In contrast, exo roots were significantly more sensitive to the inhibitory effect of synthetic brassinolide. Apart from reduced growth, exo did not show severe morphological abnormalities. Gene expression analyses of leaf material identified genes that showed robust EXO-dependent expression. Growth-related genes such as WAK1, EXP5, and KCS1, and genes involved in primary and secondary metabolism showed weaker expression in exo than in wild-type plants. However, the vast majority of BR-regulated genes were normally expressed in exo. HA- and GFP-tagged EXO proteins were targeted to the apoplast. Conclusion: The EXO gene is essential for cell expansion in leaves. Gene expression patterns and growth assays suggest that EXO mediates BR-induced leaf growth. However, EXO does not control BR-levels or BR-sensitivity in the shoot. EXO presumably is involved in a signalling process which coordinates BR-responses with environmental or developmental signals. The hypersensitivity of exo roots to BR suggests that EXO plays a diverse role in the control of BR responses in the root.
Arabidopsis thaliana HYL1 is a nuclear doublestranded RNA-binding protein involved in the maturation of pri-miRNAs. A quantitative real-time PCR platform for parallel quantification of 176 primiRNAs was used to reveal strong accumulation of 57 miRNA precursors in the hyl1 mutant that completely lacks HYL1 protein. This approach enabled us for the first time to pinpoint particular members of MIRNA family genes that require HYL1 activity for efficient maturation of their precursors. Moreover, the accumulation of miRNA precursors in the hyl1 mutant gave us the opportunity to carry out 3’ and 5’ RACE experiments which revealed that some of these precursors are of unexpected length. The alignment of HYL1- dependent miRNA precursors to A. thaliana genomic sequences indicated the presence of introns in 12 out of 20 genes studied. Some of the characterized intron-containing pri-miRNAs undergo alternative splicing such as exon skipping or usage of alternative 5’ splice sites suggesting that this process plays a role in the regulation of miRNA biogenesis. In the hyl1 mutant intron-containing pri-miRNAs accumulate alongside spliced primiRNAs suggesting the recruitment of HYL1 into the miRNA precursor maturation pathway before their splicing occurs.
The GABI Primary Database, GabiPD (http:// www.gabipd.org/), was established in the frame of the German initiative for Genome Analysis of the Plant Biological System (GABI). The goal of GabiPD is to collect, integrate, analyze and visualize primary information from GABI projects. GabiPD constitutes a repository and analysis platform for a wide array of heterogeneous data from high-throughput experiments in several plant species. Data from different ‘omics’ fronts are incorporated (i.e. genomics, transcriptomics, proteomics and metabolomics), originating from 14 different model or crop species. We have developed the concept of GreenCards for textbased retrieval of all data types in GabiPD (e.g. clones, genes, mutant lines). All data types point to a central Gene GreenCard, where gene information is integrated from genome projects or NCBI UniGene sets. The centralized Gene GreenCard allows visualizing ESTs aligned to annotated transcripts as well as displaying identified protein domains and gene structure. Moreover, GabiPD makes available interactive genetic maps from potato and barley, and protein 2DE gels from Arabidopsis thaliana and Brassica napus. Gene expression and metabolic-profiling data can be visualized through MapManWeb. By the integration of complex data in a framework of existing knowledge, GabiPD provides new insights and allows for new interpretations of the data.
Background: The development of bioinformatics databases, algorithms, and tools throughout the last years has lead to a highly distributedworld of bioinformatics services. Without adequatemanagement and development support, in silico researchers are hardly able to exploit the potential of building complex, specialized analysis processes from these services. The Semantic Web aims at thoroughly equipping individual data and services with machine-processable meta-information, while workflow systems support the construction of service compositions. However, even in this combination, in silico researchers currently would have to deal manually with the service interfaces, the adequacy of the semantic annotations, type incompatibilities, and the consistency of service compositions. Results: In this paper, we demonstrate by means of two examples how Semantic Web technology together with an adequate domain modelling frees in silico researchers from dealing with interfaces, types, and inconsistencies. In Bio-jETI, bioinformatics services can be graphically combined to complex services without worrying about details of their interfaces or about type mismatches of the composition. These issues are taken care of at the semantic level by Bio-jETI’s model checking and synthesis features. Whenever possible, they automatically resolve type mismatches in the considered service setting. Otherwise, they graphically indicate impossible/incorrect service combinations. In the latter case, the workflow developermay either modify his service composition using semantically similar services, or ask for help in developing the missing mediator that correctly bridges the detected type gap. Newly developed mediators should then be adequately annotated semantically, and added to the service library for later reuse in similar situations. Conclusion: We show the power of semantic annotations in an adequately modelled and semantically enabled domain setting. Using model checking and synthesis methods, users may orchestrate complex processes from a wealth of heterogeneous services without worrying about interfaces and (type) consistency. The success of this method strongly depends on a careful semantic annotation of the provided services and on its consequent exploitation for analysis, validation, and synthesis. We are convinced that these annotations will become standard, as they will become preconditions for the success and widespread use of (preferred) services in the Semantic Web
Injection of a mixture of HAuCl4 and cellulose dissolved in the ionic liquid (IL) 1-butyl-3-methylimidazolium chloride [Bmim]Cl into aqueous NaBH4 leads to colloidal gold nanoparticle/cellulose hybrid precipitates. This process is a model example for a very simple and generic approach towards (noble) metal/cellulose hybrids, which could find applications in sensing, sterile filtration, or as biomaterials.
Site directed mutagenesis of amino acid residues at the active site of mouse aldehyde oxidase AOX1
(2009)
Mouse aldehyde oxidase (mAOX1) forms a homodimer and belongs to the xanthine oxidase family of molybdoenzymes which are characterized by an essential equatorial sulfur ligand coordinated to the molybdenum atom. In general, mammalian AOs are characterized by broad substrate specificity and an yet obscure physiological function. To define the physiological substrates and the enzymatic characteristics of mAOX1, we established a system for the heterologous expression of the enzyme in Eschericia coli. The recombinant protein showed spectral features and a range of substrate specificity similar to the native protein purified from mouse liver. The EPR data of recombinant mAOX1 were similar to those of AO from rabbit liver, but differed from the homologous xanthine oxidoreductase enzymes. Site-directed mutagenesis of amino acids Val806, Met884 and Glu1265 at the active site resulted in a drastic decrease in the oxidation of aldehydes with no increase in the oxidation of purine substrates. The double mutant V806E/M884R and the single mutant E1265Q were catalytically inactive enzymes regardless of the aldehyde or purine substrates tested. Our results show that only Glu1265 is essential for the catalytic activity by initiating the base-catalyzed mechanism of substrate oxidation. In addition, it is concluded that the substrate specificity of molybdo-flavoenzymes is more complex and not only defined by the three characterized amino acids in the active site.
Background: Research concerning child's food intake have considered various influencing factors, for example parental feeding strategies, demographic and weight factors. At this time, however, there are few findings that explore these factors simultaneously. Accordingly, the aim of this study was to test a structural equation model regarding the associations between maternal feeding strategies and child's food intake. Methods: 556 mothers and their children between 1 and 10 years of age participated in this crosssectional study. Besides socio-demographic and weight data, the mothers were asked about their feeding strategies as well as their child's food intake. Results: The well-fitting model explained 73% of the variance in the child's consumption of healthy and 34% of unhealthy food. In addition to the effect of the mother's social status and the child's age, a rewarding and modeling feeding behavior significantly influenced the child's food intake. Conclusion: The results highlight the relevance of maternal feeding behavior on the child's food intake. In terms of preventing eating- or weight-related problems, the findings indicate the usefulness of training parents in explicit modeling behavior and avoiding food as a reward.
Background: In Arabidopsis thaliana, the family of cyclic nucleotide-gated channels (CNGCs) is composed of 20 members. Previous studies indicate that plant CNGCs are involved in the control of growth processes and responses to abiotic and biotic stresses. According to their proposed function as cation entry pathways these channels contribute to cellular cation homeostasis, including calcium and sodium, as well as to stress-related signal transduction. Here, we studied the expression patterns and regulation of CNGC19 and CNGC20, which constitute one of the five CNGC subfamilies. Results: GUS, GFP and luciferase reporter assays were used to study the expression of CNGC19 and CNGC20 genes from Arabidopsis thaliana in response to developmental cues and salt stress. CNGC19 and CNGC20 were differentially expressed in roots and shoots. The CNGC19 gene was predominantly active in roots already at early growth stages. Major expression was observed in the phloem. CNGC20 showed highest promoter activity in mesophyll cells surrounding the veins. Its expression increased during development and was maximal in mature and senescent leaves. Both genes were upregulated in the shoot in response to elevated NaCl but not mannitol concentrations. While in the root, CNGC19 did not respond to changes in the salt concentration, in the shoot it was strongly upregulated in the observed time frame (6-72 hours). Salt-induction of CNGC20 was also observed in the shoot, starting already one hour after stress treatment. It occurred with similar kinetics, irrespective of whether NaCl was applied to roots of intact plants or to the petiole of detached leaves. No differences in K and Na contents of the shoots were measured in homozygous T-DNA insertion lines for CNGC19 and CNGC20, respectively, which developed a growth phenotype in the presence of up to 75 mM NaCl similar to that of the wild type. Conclusion: Together, the results strongly suggest that both channels are involved in the salinity response of different cell types in the shoot. Upon salinity both genes are upregulated within hours. CNGC19 and CNGC20 could assist the plant to cope with toxic effects caused by salt stress, probably by contributing to a re-allocation of sodium within the plant.
Synonymous codon usage and variations in the level of isoaccepting tRNAs exert a powerful selective force on translation fidelity. We have developed an algorithm to evaluate the relative rate of translation which allows large-scale comparisons of the non-uniform translation rate on the protein biogenesis. Using the complete genomes of Escherichia coli and Bacillus subtilis we show that stretches of codons pairing to minor tRNAs form putative sites to locally attenuate translation; thereby the tendency is to cluster in near proximity whereas long contiguous stretches of slow-translating triplets are avoided. The presence of slow-translating segments positively correlates with the protein length irrespective of the protein abundance. The slow-translating clusters are predominantly located down-stream of the domain boundaries presumably to fine-tune translational accuracy with the folding fidelity of multidomain proteins. Translation attenuation patterns at highly structurally and functionally conserved domains are preserved across the species suggesting a concerted selective pressure on the codon selection and species-specific tRNA abundance in these regions.
With the increasing availability of observational data from different sources at a global level, joint analysis of these data is becoming especially attractive. For such an analysis – oftentimes with little prior knowledge about local and global interactions between the different observational variables at hand – an exploratory, data-driven analysis of the data may be of particular relevance. In the present work we used generalized additive models (GAM) in an exemplary study of spatio-temporal patterns in the tropospheric NO2-distribution derived from GOME satellite observations (1996 to 2001) at global scale. We focused on identifying correlations between NO2 and local wind fields, a quantity which is of particular interest in the analysis of spatio-temporal interactions. Formulating general functional, parametric relationships between the observed NO2 distribution and local wind fields, however, is difficult – if not impossible. So, rather than following a modelbased analysis testing the data for predefined hypotheses (assuming, for example, sinusoidal seasonal trends), we used a GAM with non-parametric model terms to learn this functional relationship between NO2 and wind directly from the data. The NO2 observations showed to be affected by winddominated processes over large areas. We estimated the extent of areas affected by specific NO2 emission sources, and were able to highlight likely atmospheric transport “pathways”. General temporal trends which were also part of our model – weekly, seasonal and linear changes – showed to be in good agreement with previous studies and alternative ways of analysing the time series. Overall, using a non-parametric model provided favorable means for a rapid inspection of this large spatio-temporal NO2 data set, with less bias than parametric approaches, and allowing to visualize dynamical processes of the NO2 distribution at a global scale.
The ability of an organism to survive depends on its capability to adapt to external conditions. In addition to metabolic versatility and efficient replication, reliable signal transduction is essential. As signaling systems are under permanent evolutionary pressure one may assume that their structure reflects certain functional properties. However, despite promising theoretical studies in recent years, the selective forces which shape signaling network topologies in general remain unclear. Here, we propose prevention of autoactivation as one possible evolutionary design principle. A generic framework for continuous kinetic models is used to derive topological implications of demanding a dynamically stable ground state in signaling systems. To this end graph theoretical methods are applied. The index of the underlying digraph is shown to be a key topological property which determines the so-called kinetic ground state (or off-state) robustness. The kinetic robustness depends solely on the composition of the subdigraph with the strongly connected components, which comprise all positive feedbacks in the network. The component with the highest index in the feedback family is shown to dominate the kinetic robustness of the whole network, whereas relative size and girth of these motifs are emphasized as important determinants of the component index. Moreover, depending on topological features, the maintenance of robustness differs when networks are faced with structural perturbations. This structural off-state robustness, defined as the average kinetic robustness of a network’s neighborhood, turns out to be useful since some structural features are neutral towards kinetic robustness, but show up to be supporting against structural perturbations. Among these are a low connectivity, a high divergence and a low path sum. All results are tested against real signaling networks obtained from databases. The analysis suggests that ground state robustness may serve as a rationale for some structural peculiarities found in intracellular signaling networks.
We propose two strategies to characterize organisms with respect to their metabolic capabilities. The first, investigative, strategy describes metabolic networks in terms of their capability to utilize different carbon sources, resulting in the concept of carbon utilization spectra. In the second, predictive, approach minimal nutrient combinations are predicted from the structure of the metabolic networks, resulting in a characteristic nutrient profile. Both strategies allow for a quantification of functional properties of metabolic networks, allowing to identify groups of organisms with similar functions. We investigate whether the functional description reflects the typical environments of the corresponding organisms by dividing all species into disjoint groups based on whether they are aerotolerant and/or photosynthetic. Despite differences in the underlying concepts, both measures display some common features. Closely related organisms often display a similar functional behavior and in both cases the functional measures appear to correlate with the considered classes of environments. Carbon utilization spectra and nutrient profiles are complementary approaches toward a functional classification of organism-wide metabolic networks. Both approaches contain different information and thus yield different clusterings, which are both different from the classical taxonomy of organisms. Our results indicate that a sophisticated combination of our approaches will allow for a quantitative description reflecting the lifestyles of organisms.
Background: The loss of photosynthesis has occurred often in eukaryotic evolution, even more than its acquisition, which occurred at least nine times independently and which generated the evolution of the supergroups Archaeplastida, Rhizaria, Chromalveolata and Excavata. This secondary loss of autotrophic capability is essential to explain the evolution of eukaryotes and the high diversity of protists, which has been severely underestimated until recently. However, the ecological and evolutionary scenarios behind this evolutionary ‘‘step back’’ are still largely unknown. Methodology/Principal Findings: Using a dynamic model of heterotrophic and mixotrophic flagellates and two types of prey, large bacteria and ultramicrobacteria, we examine the influence of DOC concentration, mixotroph’s photosynthetic growth rate, and external limitations of photosynthesis on the coexistence of both types of flagellates. Our key premises are: large bacteria grow faster than small ones at high DOC concentrations, and vice versa; and heterotrophic flagellates are more efficient than the mixotrophs grazing small bacteria (both empirically supported). We show that differential efficiency in bacteria grazing, which strongly depends on cell size, is a key factor to explain the loss of photosynthesis in mixotrophs (which combine photosynthesis and bacterivory) leading to purely heterotrophic lineages. Further, we show in what conditions an heterotroph mutant can coexist, or even out-compete, its mixotrophic ancestor, suggesting that bacterivory and cell size reduction may have been major triggers for the diversification of eukaryotes. Conclusions/Significance: Our results suggest that, provided the mixotroph’s photosynthetic advantage is not too large, the (small) heterotroph will also dominate in nutrient-poor environments and will readily invade a community of mixotrophs and bacteria, due to its higher efficiency exploiting the ultramicrobacteria. As carbon-limited conditions were presumably widespread throughout Earth history, such a scenario may explain the numerous transitions from phototrophy to mixotrophy and further to heterotrophy within virtually all major algal lineages. We challenge prevailing concepts that affiliated the evolution of phagotrophy with eutrophic or strongly light-limited environments only.
Human information processing depends critically on continuous predictions about upcoming events, but the temporal convergence of expectancy-based top-down and input-driven bottom-up streams is poorly understood. We show that, during reading, event-related potentials differ between exposure to highly predictable and unpredictable words no later than 90 ms after visual input. This result suggests an extremely rapid comparison of expected and incoming visual information and gives an upper temporal bound for theories of top-down and bottom-up interactions in object recognition.
ChlamyCyc : an integrative systems biology database and web-portal for Chlamydomonas reinhardtii
(2009)
Background: The unicellular green alga Chlamydomonas reinhardtii is an important eukaryotic model organism for the study of photosynthesis and plant growth. In the era of modern highthroughput technologies there is an imperative need to integrate large-scale data sets from highthroughput experimental techniques using computational methods and database resources to provide comprehensive information about the molecular and cellular organization of a single organism. Results: In the framework of the German Systems Biology initiative GoFORSYS, a pathway database and web-portal for Chlamydomonas (ChlamyCyc) was established, which currently features about 250 metabolic pathways with associated genes, enzymes, and compound information. ChlamyCyc was assembled using an integrative approach combining the recently published genome sequence, bioinformatics methods, and experimental data from metabolomics and proteomics experiments. We analyzed and integrated a combination of primary and secondary database resources, such as existing genome annotations from JGI, EST collections, orthology information, and MapMan classification. Conclusion: ChlamyCyc provides a curated and integrated systems biology repository that will enable and assist in systematic studies of fundamental cellular processes in Chlamydomonas. The ChlamyCyc database and web-portal is freely available under http://chlamycyc.mpimp-golm.mpg.de.
For three small, mountainous catchments in Germany two medium-range forecast systems are compared that predict precipitation for up to 5 days in advance. One system is composed of the global German weather service (DWD) model, GME, which is dynamically downscaled using the COSMO-EU regional model. The other system is an empirical (expanded) downscaling of the ECMWF model IFS. Forecasts are verified against multi-year daily observations, by applying standard skill scores to events of specified intensity. All event classes are skillfully predicted by the empirical system for up to five days lead time. For the available prediction range of one to two days it is superior to the dynamical system.
Spatial patterns as well as temporal dynamics of soil moisture have a major influence on runoff generation. The investigation of these dynamics and patterns can thus yield valuable information on hydrological processes, especially in data scarce or previously ungauged catchments. The combination of spatially scarce but temporally high resolution soil moisture profiles with episodic and thus temporally scarce moisture profiles at additional locations provides information on spatial as well as temporal patterns of soil moisture at the hillslope transect scale. This approach is better suited to difficult terrain (dense forest, steep slopes) than geophysical techniques and at the same time less cost-intensive than a high resolution grid of continuously measuring sensors. Rainfall simulation experiments with dye tracers while continuously monitoring soil moisture response allows for visualization of flow processes in the unsaturated zone at these locations. Data was analyzed at different spacio-temporal scales using various graphical methods, such as space-time colour maps (for the event and plot scale) and binary indicator maps (for the long-term and hillslope scale). Annual dynamics of soil moisture and decimeterscale variability were also investigated. The proposed approach proved to be successful in the investigation of flow processes in the unsaturated zone and showed the importance of preferential flow in the Malalcahuello Catchment, a datascarce catchment in the Andes of Southern Chile. Fast response times of stream flow indicate that preferential flow observed at the plot scale might also be of importance at the hillslope or catchment scale. Flow patterns were highly variable in space but persistent in time. The most likely explanation for preferential flow in this catchment is a combination of hydrophobicity, small scale heterogeneity in rainfall due to redistribution in the canopy and strong gradients in unsaturated conductivities leading to self-reinforcing flow paths.
Background: Mitochondrial genomes are a valuable source of data for analysing phylogenetic relationships. Besides sequence information, mitochondrial gene order may add phylogenetically useful information, too. Sipuncula are unsegmented marine worms, traditionally placed in their own phylum. Recent molecular and morphological findings suggest a close affinity to the segmented Annelida. Results: The first complete mitochondrial genome of a member of Sipuncula, Sipunculus nudus, is presented. All 37 genes characteristic for metazoan mtDNA were detected and are encoded on the same strand. The mitochondrial gene order (protein-coding and ribosomal RNA genes) resembles that of annelids, but shows several derivations so far found only in Sipuncula. Sequence based phylogenetic analysis of mitochondrial protein-coding genes results in significant bootstrap support for Annelida sensu lato, combining Annelida together with Sipuncula, Echiura, Pogonophora and Myzostomida. Conclusion: The mitochondrial sequence data support a close relationship of Annelida and Sipuncula. Also the most parsimonious explanation of changes in gene order favours a derivation from the annelid gene order. These results complement findings from recent phylogenetic analyses of nuclear encoded genes as well as a report of a segmental neural patterning in Sipuncula.
Background: Phylogenomic analyses recently became popular to address questions about deep metazoan phylogeny. Ribosomal proteins (RP) dominate many of these analyses or are, in some cases, the only genes included. Despite initial hopes, hylogenomic analyses including tens to hundreds of genes still fail to robustly place many bilaterian taxa. Results: Using the phylogenetic position of myzostomids as an example, we show that phylogenies derived from RP genes and mitochondrial genes produce incongruent results. Whereas the former support a position within a clade of platyzoan taxa, mitochondrial data recovers an annelid affinity, which is strongly supported by the gene order data and is congruent with morphology. Using hypothesis testing, our RP data significantly rejects the annelids affinity, whereas a platyzoan relationship is significantly rejected by the mitochondrial data. Conclusion: We conclude (i) that reliance of a set of markers belonging to a single class of macromolecular complexes might bias the analysis, and (ii) that concatenation of all available data might introduce conflicting signal into phylogenetic analyses. We therefore strongly recommend testing for data incongruence in phylogenomic analyses. Furthermore, judging all available data, we consider the annelid affinity hypothesis more plausible than a possible platyzoan affinity for myzostomids, and suspect long branch attraction is influencing the RP data. However, this hypothesis needs further confirmation by future analyses.
G protein-coupled receptor (GPCR) genes are large gene families in every animal, sometimes making up to 1-2% of the animal's genome. Of all insect GPCRs, the neurohormone (neuropeptide, protein hormone, biogenic amine) GPCRs are especially important, because they, together with their ligands, occupy a high hierarchic position in the physiology of insects and steer crucial processes such as development, reproduction, and behavior. In this paper, we give a review of our current knowledge on Drosophila melanogaster GPCRs and use this information to annotate the neurohormone GPCR genes present in the recently sequenced genome from the honey bee Apis mellifera. We found 35 neuropeptide receptor genes in the honey bee (44 in Drosophila) and two genes, coding for leucine-rich repeats-containing protein hormone GPCRs (4 in Drosophila). In addition, the honey bee has 19 biogenic amine receptor genes (21 in Drosophila). The larger numbers of neurohormone receptors in Drosophila are probably due to gene duplications that occurred during recent evolution of the fly. Our analyses also yielded the likely ligands for 40 of the 56 honey bee neurohormone GPCRs identified in this study. In addition, we made some interesting observations on neurohormone GPCR evolution and the evolution and co-evolution of their ligands. For neuropeptide and protein hormone GPCRs, there appears to be a general co-evolution between receptors and their ligands. This is in contrast to biogenic amine GPCRs, where evolutionarily unrelated GPCRs often bind to the same biogenic amine, suggesting frequent ligand exchanges ("ligand hops") during GPCR evolution. (c) 2006 Elsevier Ltd. All rights reserved.
Models employed in exercise psychology highlight the role of reflective processes for explaining behavior change. However, as discussed in social cognition literature, information-processing models also consider automatic processes (dual-process models). To examine the relevance of automatic processing in exercise psychology, we used a priming task to assess the automatic evaluations of exercise stimuli in physically active sport and exercise majors (n = 32), physically active nonsport majors (n = 31), and inactive students (n = 31). Results showed that physically active students responded faster to positive words after exercise primes, whereas inactive students responded more rapidly to negative words. Priming task reaction times were successfully used to predict reported amounts of exercise in an ordinal regression model. Findings were obtained only with experiential items reflecting negative and positive consequences of exercise. The results illustrate the potential importance of dual-process models in exercise psychology.
Sehend werden
(2009)
rezensiertes Werk: Sich aussetzen : das Wort ergreifen ; Texte und Bilder zum 80. Geburtstag von Christa Wolf / hrsg. von Therese Hörnigk im Auftr. des Literaturforums im Brecht-Haus und in Zusammenarbeit mit der Stiftung Preußische Seehandlung. - Göttingen : Wallstein-Verl., 2009. - 192 S. : Ill. ISBN 978-3-8353-0481-9
Background: Very recently a gene marker panel that allows the mutational analysis of APC, CTNNB1, B-RAF and K-RAS was conceived. The aim of the present study was to use the 4-gene marker panel covering the Wnt and Ras-Raf-MEK-MAPK signalling pathways to determine the percentage of sporadic colorectal carcinomas (CRC) carrying at least one of the four above-mentioned genes in a mutated form alone and/or in combination with microsatellite instability (MSI) and to compare the sensitivity of the gene marker panel used in this study with that of gene marker panels previously reported in the scientific literature. Methods: CTNNB1 and B-RAF were screened by PCR-single-strand conformation polymorphism analysis and K-RAS gene mutations by restriction fragment length polymorphism analysis. For the mutational analysis of the APC gene mutation cluster region (codons 1243–1567) direct DNA sequencing was performed. The U.S. National Cancer Institute microsatellite panel (BAT25, BAT26, D2S123, D5S346 and D17S250) was used for MSI analysis. Results: It could be shown that about 80% of early stage CRC (UICC stages I and II) and over 90% of CRC in the UICC stage IV carried at least one mutated gene and/or showed MSI. No significant increase in the gene mutation frequencies could be determined when comparing tumours in the UICC stage I with those in UICC stage IV. Conclusions: When compared with previously published gene marker panels the 4-gene marker panel used in the present study shows an excellent performance, allowing to detect genetic alterations in 80–90% of human sporadic CRC samples analyzed.
Heterocyclic aromatic amines (HCAs) are formed in meat cooked at high temperatures for a long time or over an open flame. In this context 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), the most abundant HCA in cooked meat, has been suggested to be involved in colon and prostate carcinogenesis. In the latter case it has been reported that: (1) roughly 50% of Fischer F344 male rats treated with PhIP develop carcinomas in the ventral prostate lobe at 1 year of age; (2) inflammation precedes prostatic intraepithelial neoplasia in PhIP-fed rats; (3) inflammation specifically occurs in the ventral prostate lobe of PhIP-fed rats. To test whether PhIP by itself leads to inflammation in the colon and whether a human-relevant concentration of PhIP is able to induce preneoplastic lesions in the colon, male F344 rats were fed 0.1 or 100 ppm PhIP for up to 10 months and thereafter the colon tissue was analyzed histochemically. In none of the experimental groups signs of acute or chronic colonic inflammation were observed. 0.1 ppm PhIP leads to the development of hyperplastic and dysplastic lesions in the colon of single animals, but the incidence of these lesions does not reach a statistical significance. In contrast, in rats fed 100 ppm PhIP for 10 months hyperplastic and dysplastic colonic lesions were induced in a statistically significant number of animals. It is concluded that: (1) the induction of preneoplastic lesions in rat colon by PhIP is not preceded or accompanied by an inflammatory process; (2) a human-relevant concentration of PhIP alone is not sufficient to initiate colon carcinogenesis in rats.
From the dichloromethane-methanol (1:1) extract of the seed pods of Derris trifoliata, a new flavanone derivative (S)-lupinifolin 4´-methyl ether was isolated. In addition, the known flavonoids lupinifolin and rotenone were identified. The structures were determined on the basis of spectroscopic evidence. Lupinfolin showed moderate in vitro antiplasmodial activity against the D6 (chloroquine-sensitive) and W2 (chloroquineresistant) strains of Plasmodium falciparum. The different parts of this plant showed larvicidal activities against Aedes aegypti and rotenoids were identified as the active principles.
ERP-Architekturen
(2010)
From the seedpods of Tephrosia elata, a new β-hydroxydihydrochalcone named (S)-elatadihydrochalcone was isolated. In addition, the known flavonoids obovatachalcone, obovatin, obovatin methyl ether and deguelin were identified. The structures were determined on the basis of spectroscopic evidence. The crude extract and the flavonoids obtained from the seedpods of this plant showed antiplasmodial activities. The literature NMR data on β-hydroxydihydrochalcones is reviewed and the identity of some of the compounds assigned β-hydroxydihydrochalcone skeleton is questioned.
Source, topography and excitatory effects of GABAergic innervation in cockroach salivary glands
(2009)
Cockroach salivary glands are innervated by dopaminergic and serotonergic neurons. Both transmitters elicit saliva secretion. We studied the distribution pattern of neurons containing gamma-aminobutyric acid ( GABA) and their physiological role. Immunofluorescence revealed a GABA-immunoreactive axon that originates within the subesophageal ganglion at the salivary neuron 2 (SN2) and this extends within the salivary duct nerve towards the salivary gland. GABA-positive fibers form a network on most acinar lobules and a dense plexus in the interior of a minor fraction of acinar lobules. Co-staining with anti-synapsin revealed that some putative GABAergic terminals seem to make pre-synaptic contacts with GABA-negative release sites. Many putative GABAergic release sites are at some distance from other synapses and at distance from the acinar tissue. Intracellular recordings from isolated salivary glands have revealed that GABA does not affect the basolateral membrane potential of the acinar cells directly. When applied during salivary duct nerve stimulation, GABA enhances the electrical response of the acinar cells and increases the rates of fluid and protein secretion. The effect on electrical cell responses is mimicked by the GABA(B) receptor agonists baclofen and SKF97541, and blocked by the GABAB receptor antagonists CGP52432 and CGP54626. These findings indicate that GABA has a modulatory role in the control of salivation, acting presynaptically on serotonergic and/or dopaminergic neurotransmission.
Dopamine is found in many invertebrate organisms, including insects, however, the mechanisms through which this amine operates remain unclear. We have expressed two dopamine receptors cloned from honey bee (AmDOP1 and AmDOP2) in insect cells (Spodoptera frugiperda), and compared their pharmacology directly using production of cAMP as a functional assay. In each assay, AmDOP1 receptors required lower concentrations of dopamine and 6,7-ADTN for maximal activation than AmDOP2 receptors. Conversely, butaclamol and cis(Z)-flupentixol were more potent at blocking the cAMP response mediated through AmDOP2 than AmDOP1 receptors. Expression of AmDOP1, but not AmDOP2, receptors significantly increased levels of cAMP even in the absence of ligand. This constitutive activity was blocked by cis(Z)-flupentixol. This work provides the first evidence of a constitutively activated dopamine receptor in invertebrates and suggests that although AmDOP1 and AmDOP2 share much less homology than their vertebrate counterparts, they display a number of functional parallels with the mammalian D1-like dopamine receptors.
Electro-chemical signal transduction is the basis of communication between n eurons and their target cells. An important group of neuroactive substances that are released by action potentials from neurons are the biogenic amines. These a re small organic molecules that bind to specific receptors located in the target cell membrane. Once activated these receptors cause changes in the intracellula r concentration of second messengers, i.e. cyclic nucleotides, phosphoinositides , or Ca2+, leading to slow but long-lasting cellular responses. Biochemical, pha rmacological, physiological, and molecular biological approaches have unequivoca lly shown that biogenic amines are important regulators of cellular function in both vertebrates and invertebrates. In this review, we will concentrate on the p roperties of two biogenic amines and their receptors that were originally identi fied in invertebrates: tyramine and octopamine.
Der gemeinsame Wandel der inselkeltischen Sprachen wie auch des Englischen vom vorwiegend synthetischen Typus zum vorwiegend analytischen Typus läßt sich vermutlich auf einen ca. 1500 Jahre dauernden intensiven Sprachenkontakt zwischen diesen Sprachen zurückführen. Heute ist das Englische die analytischste Sprache der Britischen Inseln und Irlands, gefolgt vom Walisischen, Bretonischen und Irischen. Letzteres ist von den genannten Sprachen noch am weitesten morphologisch komplex.
Content Social stereotypes and responsibility attributions to victims of rape Atributing responsibillty to rape victims: a German study Rape myth acceptance and responsibility judgments: a British study Police officers' definitions of rape A study on cognitive prototypes of rape Conclusion References
Sinai
(1995)
Vorwort: In der Zeit vom 3o. September 1994 bis zum 2 1 . Oktober 1994 fand eine Exkursion auf den Sinai statt, die Studenten aus den Bereichen Geschichte, Geographie und Sozialwissenschaften vereinte. Ziel der Unternehmung war es, die Studenten mit der Geographie des Sinai vertraut zu machen, sie in die historischen Gegebenheiten der Landschaft und in archäologische Forschungen einzuführen und den sich abzeichnenden Wandel dieser Region zu beobachten. In Kairo wurde den Studenten eine Einführung in die Probleme des Landes gegeben: Dr. Nastansky, der Leiter des DAAD Kairo, sprach über das Bildungswesen in Ägypten, Dr. Claus von der Gesellschaft für Technische Zusammenarbeit äußerte sich zu Fragen der Entwicklungshilfe, Dr. Pflugrad - Abdel Aziz über deutsche Architekten in Ägypten und Volkmar Wenzel von der deutschen Botschaft zu Fragen der Innen- und Außenpolitik Ägyptens. Auch nach der Exkursion konnten die gewonnenen Erkenntnisse und Erfahrungen durch Vorträge und Diskussionen vertieft werden. Dr. Großmann vom Deutschen Archäologischen Institut sprach zur Architektur auf dem Sinai, Sherif Algohary von der Ägyptischen Atomenergiebehörde zu alternativen Wohn- und Lebensformen in Ägypten und Prof. Kilany, der Vizepräsident der Grünen Partei Ägyptens, zur Umweltsituation des Landes. Zwischen diesen Veranstaltungen gab es Zeit, sich mit den Problemen der 17 Millionenstadt vertraut zu machen, Denkmäler und Museen kennenzulernen und erste Kontakte zu knüpfen. Die Exkursion in Richtung Osten begann mit der Besichtigung einer mittelgroßen Stadt nordöstlich von Kairo, die - in der Wüste neugebaut - aber nicht bezogen war. Das war Anlaß, über Infrastruktur, Planungsansätze und Zielvorstellungen zu diskutieren. Auch die bei der Stadt Bilbeis gelegene unbrauchbar gewordene Schleusenanlage forderte das Nachdenken über den Umgang mit Bauten der Infrastruktur heraus. Der Aufenthalt in Zagazig - einer im Ostdelta gelegenen Großstadt - wurde zu einer Begegnung mit der fünftausendjährigen Geschichte Ägyptens. Der Besuch bei Handwerkern, die wie vor Tausenden von Jahren ihre Krüge herstellen und ihre Ziegel streichen und die Tempelanlage von Teil Basta einerseits, eine moderne Ziegelei und die Einladung der Landwirtschaftlichen Fakultät der Universität andererseits, machen das Spannungsfeld deutlich, in dem Ägypten und Ägypter heute leben. Diese Eindrücke wurden durch den Besuch der riesigen Tempelanlage von Tanis und das in der zweiten Hälfte des 19. Jahrhundert entstände Ismailiya verstärkt. Die eigentliche Sinai-Exkursion erfolgte mit der Aufteilung in Gruppen. Ein Teil befaßte sich, von Kantara ausgehend, mit der speziellen Problematik des Nordsinai, mit dem Suez-Kanal, mit dem Bau des zur Bewässerung dienenden Friedenskanals und dem sozialen Wandel in dieser Region. Eine zweite Gruppe widmete sich der Lebensweise der Beduinen, der Veränderung ihrer Lebenslage und stellte sich kritisch den Problemen des anwachsenden Tourismus. Andere verfolgten Fragen der politischen Entwicklung auf dem Sinai, insbesondere in dem Spannungsfeld zwischen dem arabisch-nationalbewußten Ägypten und dem nicht weniger selbstbewußten Israel. Daß es sich dabei nicht um einen abgeschlossenen Prozeß handelt, macht nicht nur die jüngste Geschichte deutlich, sondern wurde auch jedem Teilnehmer klar, der z.T. im Schutz der Polizei das Land bereiste. Die Exkursion wurde aus Mitteln des Deutschen Akademischen Austauschdienstes und der Universität Potsdam finanziert. Mit ihr sollte das Ziel erreicht werden, die Grundlage für weitere wissenschaftliche Arbeiten zu legen. Der wesentliche Gewinn für jeden lag darin, daß ein unmittelbarer Kontakt zu den Bewohnern des Landes möglich war, der durch eine zuvor erarbeitete Aufgabenstellung zu einer konkreten Erfahrung wurde.
Nasledujúci príspevok poslal časopisu Viera a život vedecký pracovník katolíckej teologickej fakulty na Regensburskej univerzite (Nemecko) pán Stefan Gatzhammer, M. A., Líc. iur. can. Podkladom pre článok bola rozpracovaná vedecká štúdia, preto aj nemecká pôvodina príspevku mala bohaté a dôkladné poznámky. S láskavým súhlasom autora sme pre potreby našich čitateľov poznámky zjednodušili. Pôvodný nemecký titul článku znie: „Die Ausweisung der Jesuiten aus Portugal 1759/60. Der Brasilienmissionar P. Josef Keyling SJ aus Schemnitz." Príspevok do slovenčiny preložila Zuzana Vaňová.
Bei N = 101 Arbeitnehmern verschiedener Berufe wurden mit der Experience Sampling Method (ESM) eine Woche lang Daten zum Flow-Erleben, zu Glück/Zufriedenheit und zur Zielausrichtung laufender Aktivitäten erhoben (N = 4603 Messungen). Die Daten wurden mit GLMM-Analysen ausgewertet. Auch bei der jetzt vollständigen Erfassung aller Flow-Komponenten mit der FKS bestätigte sich das „Paradoxon der Arbeit“, wonach während der Arbeit höhere Flow-Werte, aber niedrigere Werte für Glück/Zufriedenheit auftreten als jeweils in der Freizeit. Während der Arbeit waren Aktivitäten häufiger auf die Erreichung von Zielen ausgerichtet als während der Freizeit. Die Zielausrichtung wirkte auf Flow vs. Glück/Zufriedenheit signifikant verschieden. Während der Arbeit hat die Zielausrichtung auf Flow einen stark positiven Effekt, auf Glück/Zufriedenheit jedoch nicht. Im Freizeitbereich war der Effekt von Zielausrichtung auf Glück/Zufriedenheit sogar negativ. Das „Paradoxon der Arbeit“ lässt sich partiell als Effekt der Zielausrichtung verstehen.
Fachvortrag gehalten beim 8. Bayerischen Berufsbildungskongress Aus dem Inhalt: Das Projekt be-online (www.projekt-be-online.de) entwickelt ein beratungsorientiertes Bildungsangebot im Internet für die Erwachsenenbildung und die betrieblich-berufliche Weiterbildung. Im Mittelpunkt stehen virtuelle Bildungsräume mit kooperativen Lernzusammenhängen, die in geschlossenen Online-Foren realisiert werden. Das Projekt wird vom Bundesministerium für Bildung und Forschung gefördert und in Bildungseinrichtungen der Gewerkschaft ver.di umgesetzt. Didaktische Grundlage ist das Konzept „fallorientierte Weiterbildung“, das von Kurt R. Müller u.a. (Universität der Bundeswehr München) entwickelt und vom Bayerischen Staatsministerium für Arbeit und Sozialordnung, Familie und Frauen gefördert wurde.
First studies of electron transfer in [N]phenylenes were performed in bimolecular quenching reactions of angular [3]- and triangular [4]phenylene with various electron acceptors. The relation between the quenching rate constants kq and the free energy change of the electron transfer (ΔG0CS ) could be described by the Rehm-Weller equation. From the experimental results, a reorganization energy λ of 0.7 eV was derived. Intramolecular electron transfer reactions were studied in an [N]phenylene bichomophore and a corresponding reference compound. Fluorescence lifetime and quantum yield of the bichromophor display a characteristic dependence on the solvent polarity, whereas the corresponding values of the reference compound remain constant. From the results, a nearly isoenergonic ΔG0CS can be determined. As the triplet quantum yield is nearly independent of the polarity, charge recombination leads to the population of the triplet state.
Pestizideinsatz gegen die Rosskastanien-Miniermotte (Cameraria ohridella) im Stadtgebiet Potsdam
(2005)
In Deutschland hat sich in den letzten zehn Jahren die aus dem Balkan eingewanderte Rosskastanien-Miniermotte verbreitet; sie richtet vor allem in Ballungsgebieten an der weiß blühenden Rosskastanie starke Schäden an. Neben der vollständigen mechanischen Beseitigung und Entsorgung des Falllaubes im Herbst eignen sich zur Bekämpfung chemische Pflanzenschutzmittel. In Potsdam sind 2001 und 2003 an zwei Standorten befallene Rosskastanien versuchsweise mit zwei unterschiedlichen Pestiziden erfolgreich behandelt worden. 2005 wurden die Standorte beprobt und die Bodenproben auf Rückstände der verwendeten Mittel untersucht. TerraTech möchte Kommunen mit vergleichbarem Problem Hinweise auf Bekämpfungsmethoden geben, veröffentlicht diesen Beitrag aber vor allem unter dem Gesichtspunkt des Boden- und Grundwasserschutzes.
Die Anwendung zweier ähnlicher fasergekoppelte Diodenlaser-Spektrometer-Systeme werden vorgestellt. Basis sind handelsübliche DFB-Laserdioden der optischen Kommunikationstechnik. Der faseroptische Aufbau, das Detektionsverfahren (2f Wellenlängenmodulations-Spektroskopie mit Balanced Receiver), Rauschverhalten und Detektionslimit werden diskutiert. Zur in-situ Plasma-Diagnostik von CO- und CO2-Konzentrationen in industriellen CO2-Lasern der Materialbearbeitung wurde eine Wellenlänge von 1582 nm verwendet. Bei einem Gasdruck von 100 hPa und einer Absorptionsweglänge von 14,9 cm wurden mit einer Laserdiode simultan CO- und CO2-Konzentrationen von 0% bis 11% im Gasgefäß bei laufender Hochfrequenzgasentladung des CO2-Lasers zeitaufgelöst gemessen. Vorgestellt und diskutiert werden Aufbau und Eigenschaften des Spektrometers sowie die Ergebnisse der dynamischen Gasanalysen, die zu einer Verbesserung der Katalysator-Technik im CO2-Laser beigetragen haben.Mit isotopenaufgelöster CO- und CO2-Spektroskopie können biologische Gasaustauschprozesse, z.B. in Gasen aus dem Erdboden untersucht werden. Hierzu wurde ein fasergekoppeltes feldtaugliches Diodenlaser-Spektrometer bei Wellenlängen um 1605 nm zur Messungder Isotopologe 12C16O, 13C16O, 12C18O und 12C16O2, 13C16O2, 12C18O16O aufgebaut. Die Messung erfolgt extraktiv in Langwegzellen mit unterschiedlichen Absorptionsweglängen von 100.9 m und 29.9 m. Es werden Kalibrationsmessungen zur Linearität und zur Präzision der Bestimmung der Isotopenverhältnisse sowie Wiederholungsmessungen zur Stabilität vorgestellt. Nachweisgrenzen von wenigen ppm konnten für die CO- und CO2-Isotopologen erhalten werden.
Contents: Introduction Experimental Techniques: The LIF demonstrator unit - The LIF demonstrator unit - The mobile LIF spectrometer OPTIMOS - Investigated petroleum products and soil samples Results and Discussion: Photophysical properties of the petroleum products LIF spectroscopic investigations of oil-spiked samples LIF spectroscopic investigations of real-world soils Conclusions
The fluorescence properties and the fluorescence quenching by Tb3+ of substituted benzoic acid were investigated in solution at different pH. The substituted benzoic acids were used as simple model compounds for chromophores present in humic substances (HS). It is shown that the fluorescence properties of the model compounds resemble fluorescence of HS quite well. A major factor determining the fluorescence of model compounds are proton transfer reactions in the electronically excited state. It is intriguing that the fluorescence of the model compounds was almost not quenched by Tb3+ while the HS fluorescence was decreased very effectively. From our results we concluded that proton transfer reactions as well as conformational reorientation processes play an important role in the fluorescence of HS. The luminescence of bound Tb3+ was sensitized by an energy transfer step upon excitation of the model compounds and of HS, respectively. For HS the observed sensitization was dependent on its origin indicating differences 1) in the connection between chromophores and binding sites and 2) in the energy levels of the chromophore triplet states. Hence, the observed sensitization of the Tb3+ luminescence could be useful to characterize structural differences of HS in solution. Interlanthanide energy transfer between Tb3+ and Nd3+ was used to determine the average distance R between both ions using the well-known formalism of luminescence resonance energy transfer. R was dependent on the origin of the HS reflecting the difference in structure. The value of Rmin seemed to be a unique feature of the HS. It was further found that upon variation of the pH R also changed. This demonstrates that the measurement of interlanthanide energy transfer can be used as a direct method to monitor conformational changes in HS.
This paper argues that the texts surviving from the Old English period do not reflect the spoken language of the bulk of the population under Anglo-Saxon elite domination. While the Old English written documents suggest that the language was kept remarkably unchanged, i.e. was strongly monitored during the long OE period (some 500 years!), the spoken and "real Old English" is likely to have been very different and much more of the type of Middle English than the written texts. "Real Old Engish", i.e. of course only appeared in writing after the Norman Conquest. Middle English is therefore claimed to have begun with the 'late British' speaking shifters to Old English. The shift patterns must have differed in the various part of the island of Britain, as the shifters became exposed to further language contact with the Old Norse adstrate in the Danelaw areas and the Norman superstrate particularly in the South East, the South West having been least exposed to language contact after the original shift from 'Late British' to Old English. This explains why the North was historically the most innovative zone. This also explains the conservatism of the present day dialects in the South West. It is high time that historical linguists acknowledge the arcane character of the Old English written texts.
Bei Entscheidungen über abzulösende oder neue Anwendungssysteme kann mit Hilfe funktionaler Anforderungen immer nur der gegenwärtige oder vorhersehbare Bedarf ermittelt werden. In einem turbulenten Umfeld sind die Anwendungssysteme jedoch häufig langere Zeit im Einsatz als die Anforderungen gültig sind, mit Hilfe derer sie ausgewählt wurden. An der Universität Potsdam wird im Rahmen des BMBF-Projektes CHANGE eine Vorgehensweise zur Ermittlung der Zukunftsfähigkeit unternehmensweiter Anwendungssysteme entwickelt, deren wesentliche Merkmale in diesem Beitrag beschrieben werden.
Optimierung werksübergreifender Geschäftsprozesse am Beispiel der Automobilzuliefererindustrie
(2005)
Die Bedeutung der Zulieferer für die Automobilhersteller wächst stetig, weil die Zulieferer immer stärker in den gesamten Wertschöpfungsprozess des Herstellers eingebunden werden und somit ständig Planung, Qualität und Logistikabläufe optimiert werden müssen. Betriebliche Anwendungen, wie Enterprise Resource Planning- (ERP-) oder Produktionsplanung- und –steuerungs-(PPS-) Systeme werden benötigt, um den störungsfreien und reibungslosen Ablauf der Geschäftsprozesse und damit die ständige Lieferfähigkeit gegenüber dem Automobilhersteller zu garantieren [1]. Anhand eines Marktüberblicks werden in diesem Beitrag innovative Ansätze, Möglichkeiten und Koordinationsmechanismen zur Unterstützung der Produktion in verteilten Standorten von aktuellen ERP-/PPS-Systemen vorgestellt.
Die Orientierung am Kunden und dessen individuellen Wünschen ist heutzutage von großer Bedeutung. Mit Hilfe eines Produktkonfigurationssystems ist es möglich, Produkte nach bestimmten Regeln aus bestimmten Bauteilen virtuell zu entwickeln [1] und somit die gewünschten Leistungsmerkmale der Kunden auf ihre Durchführbarkeit hin zu überprüfen. In der vorliegenden Marktuntersuchung wurden die Leistungsfähigkeit von Konfiguratoren sowohl in ERP-/PPS-Systemen als auch als Stand-alone-Lösung untersucht und darauf überprüft, inwiefern sie zur Bewältigung komplexer und variantenreicher Produktgestaltungsaufgaben geeignet sind.
Marktüberblick
(2005)
Diese Marktstudie vermittelt einen Überblick über Software, die zur Unterstützung von Wissensmanagement eingesetzt werden kann und berücksichtigt dabei die Spannweite von spezialisierten Suchmaschinen bis zu umfassenden integrierten Wissensmanagementsystemen. Die untersuchte Software bietet sowohl Unterstützung bei Community-orientierten Wissensmanagementansätzen als auch bei Information Retrieval. Die Einsatzmöglichkeiten sind genauso unterschiedlich wie die heterogenen Anforderungen von Unternehmen und Organisationen, die diese an Wissensmanagement stellen. Eine direkte Vergleichbarkeit aller untersuchten Softwareprodukte ist daher nicht sinnvoll.
Marktüberblick
(2005)
Für viele Unternehmen hat sich der Stellenwert der Kundenbeziehung in den letzten Jahren nachhaltig verändert. Da Wettbewerbsfähigkeit häufig über die Beziehung zum Kunden definiert wird, ist den meisten Unternehmen die Bedeutung des Kundenwissens durchaus bewusst. Schon immer war die Beziehung zum Kunden für ein Unternehmen existenzkritisch, jedoch hat sich dazu die Situation auf den eigenen Absatzmärkten stark gewandelt. Durch den steigenden internationalen Wettbewerb kommt es zunehmend zu gesättigten Absatzmärkten und erhöhten Kostendruck. Weiterhin kommt seitens der Kunden ein höheres Erwartungsniveau sowie abnehmende Kundenloyalität erschwerend hinzu. Diese Gründe erfordern eine neuartige Kundenorientierung im Sinne eines umfassenden Kundenbeziehungsmanagement (engl. Customer Relationship Management, CRM).
Mittelständische Industrieunternehmen setzen für ihre betrieblichen Abläufe Planungs- und Ausführungssysteme ein. Aufgrund der Turbulenzen auf Absatz- und Beschaffungsmärkten kann die Wirtschaftlichkeit und Wettbewerbsfähigkeit dieser Unternehmen nur durch permanente Anpassungen der Organisationsstrukturen und -abläufe erfolgen. In der Praxis zeigt sich eine unzureichende technologische Anpassungsfähigkeit der heute eingesetzten Standardsoftwaresysteme. Diese lassen zwar während der Einführungsphase vielfältige Konfigurationsmöglichkeiten zu, Veränderungen im laufenden Betrieb sind aber meist nur mit großem Aufwand möglich. Hier sind die Softwarehersteller in Zukunft zunehmend gefordert, wandlungsfähige Auftragsabwicklungssysteme zu entwickeln. Über die Entwicklungsphase (Build-Time) hinaus muss auch parallel zur Betriebsphase (Run-Time) der technische Fortschritt aufgrund von geänderten Anforderungen durch entsprechende Softwarereleases synchronisiert werden.
We give a necessary and sufficient condition for the existence of an increasing coupling of N (N >= 2) synchronous dynamics on S-Zd (PCA). Increasing means the coupling preserves stochastic ordering. We first present our main construction theorem in the case where S is totally ordered; applications to attractive PCAs are given. When S is only partially ordered, we show on two examples that a coupling of more than two synchronous dynamics may not exist. We also prove an extension of our main result for a particular class of partially ordered spaces.
In this paper, we consider families of time Markov fields (or reciprocal classes) which have the same bridges as a Brownian diffusion. We characterize each class as the set of solutions of an integration by parts formula on the space of continuous paths C[0; 1]; R-d) Our techniques provide a characterization of gradient diffusions by a duality formula and, in case of reversibility, a generalization of a result of Kolmogorov.
We develop a cluster expansion in space-time for an infinite-dimensional system of interacting diffusions where the drift term of each diffusion depends on the whole past of the trajectory; these interacting diffusions arise when considering the Langevin dynamics of a ferromagnetic system submitted to a disordered external magnetic field.
The authors analyse different Gibbsian properties of interactive Brownian diffusions X indexed by the d-dimensional lattice. In the first part of the paper, these processes are characterized as Gibbs states on path spaces. In the second part of the paper, they study the Gibbsian character on R^{Z^d} of the law at time t of the infinite-dimensional diffusion X(t), when the initial law is Gibbsian. AMS Classifications: 60G15 , 60G60 , 60H10 , 60J60
We prove in this paper an existence result for infinite-dimensional stationary interactive Brownian diffusions. The interaction is supposed to be small in the norm ||.||∞ but otherwise is very general, being possibly non-regular and non-Markovian. Our method consists in using the characterization of such diffusions as space-time Gibbs fields so that we construct them by space-time cluster expansions in the small coupling parameter.
Vergütung mit Zukunft
(2005)
Im derzeit angespannten gesamtwirtschaftlichen Umfeld haben Unternehmen wenig Spielräume, über eine absolute Erhöhung der Vergütung Mitarbeiter zu werben, zu binden und zu motivieren. Gerade deshalb erhält die flexible und individuelle Gestaltung des Vergütungssystems für Fach- und Führungskräfte eine herausgehobene Bedeutung.
Humankapital
(2005)
Das Personal stellt zweifellos ein Erfolgspotenzial dar. Es verkörpert eine wertvolle Ressource. Angesichts der Tatsache, dass viele Aufgaben komplexer und dynamischer werden, ist zu bedenken, dass diese eben nur von Menschen erledigt werden können und technische Hilfsmittel letztlich Selbstzweck sind. Ganz gleich, ob in der Privatwirtschaft oder in öffentlichen Unternehmen.
Das Thema Bestandsmanagement ist bereits seit Mitte der 80er Jahre bekannt. Es betrifft alle warenwirtschaftlichen Prozesse zur Planung und Steuerung von Beständen. Dabei muss es mit den Schwierigkeiten umgehen können, die aus den stetig wachsenden Marktanforderungen hervorgehen. Dazu gehört neben dem enorm hohen Kostendruck und die sich gleichzeitig stetig verkürzenden Liefer- und Produktlebenszeiten auch die rapide steigende Variantenvielfalt. Dies führt zu einem konstanten Komplexitätsanstieg innerhalb der Bestandsplanung und –steuerung ----------
Mit diesem Beitrag möchten wir aufzeigen, welchen Stellenwert psycho-physiologische Erhebungen in der Diagnostik von Fähigkeiten, Fertigkeiten und Verhaltensweisen haben. Über solche Verfahren lassen sich Stresserleben und negative Beanspruchungen zeitiger erkennen als durch Beobachtungen und Befragungen. Im Rahmen einer Pilotstudie zum Belastungserleben von Schulkindern wurden von uns Daten mittels standardisierter Fragebögen und physiologischer Messungen erhoben. Wir haben zunächst psycho-physiologische Beanspruchungszustände von Grundschulkindern im Tagesverlauf erfasst, weil der circadiane Rhythmus die prinzipielle Grundlage für alle Lebens- und Lernprozesse darstellt. Darauf basieren weiterführende Untersuchungen zu situations- und anforderungsbezogenen Beanspruchungen von Schülerinnen und Schülern, die schließlich auf das Erfassen von Beziehungen zwischen psycho-physiologischen Zuständen und Verhaltensbeobachtungen gerichtet sind. In diesem Beitrag werden Ergebnisse aus 24-Stunden-Messungen vorgestellt.
Im Rahmen eines Forschungsprojekts zur Belastung und Beanspruchung von Kindern und Jugendlichen führten die Autorinnen Untersuchungen zur Entspannungsfähigkeit von nicht behinderten und behinderten Schülerinnen und Schülern durch. Die Fähigkeit zur Entspannung wird als wichtige Voraussetzung für die Entwicklung von Leiszungsfähigkeit, Wohlbefinden und Gesundheit angesehen. Zugleich wird davon ausgegangen, dass es einen unmittelbaren Zusammenhang zwischen psychosomatischen Auffälligkeiten und dem biologisch verankerten Reaktionsmuster Entspannung gibt. In drei unterschiedlichen Versuchsgruppen werden dazu physiologische Parameter mittels Blutdruck- und Hautwiderstandsmessungen erhoben. Die Untersuchungsergebnisse lassen Schlussfolgerungen für eine veränderte Unterrichts- und Lernprozessgestaltung zu.
In vergleichenden Untersuchungen zum Belastungserleben von Schulkindern wird dargestellt, welche Einschätzungen nicht behinderte und lernbehinderte Schülerinnen und Schüler bezüglich ihrer Belastung in schulischen und außer- schulischen Situationen vornehmen. In einem Gruppenvergleich wird herausgearbeitet, inwieweit gemeinsamer Unterricht in einer Allgemeinen Schule vs. dem Unterricht in einer Sonderschule zu Angst- und Stresserleben führt. Diese subjektiv bewussten Einschätzungen der Schülerinnen und Schüler werden mit Ergebnissen aus physiologischen Messungen verglichen, die im Heft 12/ 2002 dieser Zeitschrift dargestellt wurden.
Biologische Zeitstrukturen spielen im Tagesrhythmus eines jeden Menschen eine große Rolle und beeinflussen die Leistungsfähigkeit maßgeblich. In diesem Beitrag, der Teilergebnis einer Pilotstudie ist, wird dargestellt, wie mit Hilfe von Messungen des Hautwiderstandes dragestellt werden kann, in welchem Beanspruchungszustand lernbehinderte und nicht behinderte Grundschulkinder während eines Tages sind.