Chemie im Kontext – a symbiotic implementation of a context-based teaching and learning approach

Chemie im Kontext (ChiK) is a project which aims at the improvement of chemistry teaching at secondary school in Germany. Based on a framework, which was derived from theories and empirical data on the teaching and learning of science, science education researchers and teachers work together on learning communities to transform this framework into teaching and learning practice. Funded by the German Federal Ministry of Education and the participating federal states, such learning communities have developed and tried units for almost all topics for the upper and lower secondary education. The accompanying research studies show different effects on students' motivation: The ChiK units point out the relevance of chemistry, but the student-oriented learning approach can also lead to a feeling of getting lost in the context. One reason might be seen in the result that teachers have put more emphasis on the realisation of a good context than on the second important principle of ChiK: the development of basic concepts. However, data also showed that the learning communities have indeed inspired and supported the teachers to change their teaching towards a more context-based and student-oriented teaching. The continuing work will now especially focus on the improvement of facilitating the students with a better guideline, and on the development and assessment of different science competencies

Glutaminyl cyclase contributes to the formation of focal and diffuse pyroglutamate (pGlu)-Aβ deposits in hippocampus via distinct cellular mechanisms

In the hippocampal formation of Alzheimer’s disease (AD) patients, both focal and diffuse deposits of Aβ peptides appear in a subregion- and layer-specific manner. Recently, pyroglutamate (pGlu or pE)-modified Aβ peptides were identified as a highly pathogenic and seeding Aβ peptide species. Since the pE modification is catalyzed by glutaminyl cyclase (QC) this enzyme emerged as a novel pharmacological target for AD therapy. Here, we reveal the role of QC in the formation of different types of hippocampal pE-Aβ aggregates. First, we demonstrate that both, focal and diffuse pE-Aβ deposits are present in defined layers of the AD hippocampus. While the focal type of pE-Aβ aggregates was found to be associated with the somata of QC-expressing interneurons, the diffuse type was not. To address this discrepancy, the hippocampus of amyloid precursor protein transgenic mice was analysed. Similar to observations made in AD, focal (i.e. core-containing) pE-Aβ deposits originating from QC-positive neurons and diffuse pE-Aβ deposits not associated with QC were detected in Tg2576 mouse hippocampus. The hippocampal layers harbouring diffuse pE-Aβ deposits receive multiple afferents from QC-rich neuronal populations of the entorhinal cortex and locus coeruleus. This might point towards a mechanism in which pE-Aβ and/or QC are being released from projection neurons at hippocampal synapses. Indeed, there are a number of reports demonstrating the reduction of diffuse, but not of focal, Aβ deposits in hippocampus after deafferentation experiments. Moreover, we demonstrate in neurons by live cell imaging and by enzymatic activity assays that QC is secreted in a constitutive and regulated manner. Thus, it is concluded that hippocampal pE-Aβ plaques may develop through at least two different mechanisms: intracellularly at sites of somatic QC activity as well as extracellularly through seeding at terminal fields of QC expressing projection neurons

Phänomene der unbelebten Natur. Experimente zum Thema Kunststoffe

Lück G, Demuth R. Phänomene der unbelebten Natur. Experimente zum Thema Kunststoffe. Grundschulunterricht. 1999;46(11):2-6

Der naturwissenschaftliche Sachunterricht in Lehrplänen, Unterrichtsmaterialien und Schulpraxis - Eine quantitative Analyse der Entwicklung in den letzten 25 Jahren

Strunk U, Lück G, Demuth R. Der naturwissenschaftliche Sachunterricht in Lehrplänen, Unterrichtsmaterialien und Schulpraxis - Eine quantitative Analyse der Entwicklung in den letzten 25 Jahren. Zeitschrift für Didaktik der Naturwissenschaften : ZfDN ; Biologie, Chemie, Physik. 1998;4(1):69-80

Photoelectron Spectra of Group V Compounds, VI. Methyl- and Trifluoromethyl-Cyanophosphines, MenP(CN)3-n and (CF3)nΡ(CN)3-n (n = 0, 1, 2, 3)

The He I photoelectron spectra of the series RnP(CN)3-n (R = Me, CF3; n = 0, 1, 2, 3) and of Me2ECN (E = N, P, As) are interpreted. The PE assignments are based on the comparison with the PE data of analogous halogeno and hydrogen derivatives as well as related cyano compounds and on simple MO considerations (composite molecule-approach). Hyperconjugative and inductive effects of the substituents CN, Me, F, Cl, and especially CF3 are assessed. The various effects of changing substituents or central atoms within the series are used to confirm the interpretation. The differing electronic structures of halogeno and cyano (pseudohalogeno) compounds are discussed on the basis of their PE spectra

Glutaminyl cyclase-mediated toxicity of pyroglutamate-beta amyloid induces striatal neurodegeneration

Background Posttranslational modifications of beta amyloid (Aβ) have been shown to affect its biophysical and neurophysiological properties. One of these modifications is N-terminal pyroglutamate (pE) formation. Enzymatic glutaminyl cyclase (QC) activity catalyzes cyclization of truncated Aβ(3-x), generating pE3-Aβ. Compared to unmodified Aβ, pE3-Aβ is more hydrophobic and neurotoxic. In addition, it accelerates aggregation of other Aβ species. To directly investigate pE3-Aβ formation and toxicity in vivo, transgenic (tg) ETNA (E at the truncated N-terminus of Aβ) mice expressing truncated human Aβ(3–42) were generated and comprehensively characterized. To further investigate the role of QC in pE3-Aβ formation in vivo, ETNA mice were intercrossed with tg mice overexpressing human QC (hQC) to generate double tg ETNA-hQC mice. Results Expression of truncated Aβ(3–42) was detected mainly in the lateral striatum of ETNA mice, leading to progressive accumulation of pE3-Aβ. This ultimately resulted in astrocytosis, loss of DARPP-32 immunoreactivity, and neuronal loss at the sites of pE3-Aβ formation. Neuropathology in ETNA mice was associated with behavioral alterations. In particular, hyperactivity and impaired acoustic sensorimotor gating were detected. Double tg ETNA-hQC mice showed similar Aβ levels and expression sites, while pE3-Aβ were significantly increased, entailing increased astrocytosis and neuronal loss. Conclusions ETNA and ETNA-hQC mice represent novel mouse models for QC-mediated toxicity of truncated and pE-modified Aβ. Due to their significant striatal neurodegeneration these mice can also be used for analysis of striatal regulation of basal locomotor activity and sensorimotor gating, and possibly for DARPP-32-dependent neurophysiology and neuropathology. The spatio-temporal correlation of pE3-Aβ and neuropathology strongly argues for an important role of this Aβ species in neurodegenerative processes in these models