158 research outputs found

    Young Adult Dystopian Literature. Didactic Benefits of its use in the English Subject Classroom in Norway.

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    Mastergradsoppgave, Høgskolen i Innlandet, 2018.English: This thesis examines didactic benefits of young adult (YA) dystopian literature when used in the English subject classroom in Norway. More specifically, the study investigates how working with this genre can develop young adult students’ critical thinking skills and their understanding of contemporary society, and how this can influence readers’ personal development and self-growth. Moreover, the thesis looks at the students’ development of reading and digital skills when working with YA dystopian literature in general, and Scott Westerfeld’s trilogy, Uglies (2005a), Pretties (2005b) and Specials (2006), in particular. This study is based on literary theory, mainly traditional and YA dystopian literature, and didactic theory, which is presented in a literature review. The second research method is a close reading of Westerfeld’s Uglies trilogy. The findings from both the close reading and the literature review are discussed in relation to the Common Core and English Subject Curricula, as well as the Framework for Basic Skills. Working with YA dystopia can aid young adults to meet the learning outcomes that are set by the Norwegian Directorate for Education and Training. The qualities of this type of literature make it a viable choice for work in the English subject classroom and with young adults. Nevertheless, further research in this field can consist of testing concrete teaching methods and practical classroom applications in the form of empirical research.Norsk: Formålet med denne oppgaven er å undersøke hvilke didaktiske fordeler som kan knyttes til bruken av dystopisk ungdomslitteratur i engelskfaget i norsk skole. Mer konkret drøftes hvordan denne sjangeren bidrar til utvikling og styrking av elever i ungdomsalders evner til kritisk refleksjon og deres forståelse av et moderne samfunn. Dette forbindes også med denne elevgruppens personlig utvikling. I tillegg undersøker denne studien hvordan bruk av dystopisk ungdomslitteratur kan bidra til å utvikle lese- og digitale ferdigheter. Denne oppgaven baserer seg på en spesifikk trilogi av Scott Westerfeld: Uglies (2005a), Pretties (2005b) og Specials (2006). Denne oppgaven tar utgangspunkt i litterær teori som omhandler både klassisk- og ungdomslitteratur innenfor den dystopiske sjangeren. I tillegg gjennomfører denne studien også en litterær analyse av Westerfeld sin Uglies trilogi. Funn fra analysen og teorikapitlet blir drøftet i lys av læreplanen, mer bestemt den generelle delen og læreplanen i engelsk, i tillegg til rammeverket for grunnleggende ferdigheter. Arbeid med dystopisk ungdomslitteratur i engelskfaget kan bidra til å oppnå en rekke læreplanmål. Denne sjangeren har egenskaper som gjør den egnet til arbeid med elever i ungdomsalder innenfor norsk skole. Videre forskning innenfor dette feltet kan bestå av å undersøke konkrete lærestrategier og undervisningsmetoder der bruk av dystopisk ungdomslitteratur undersøkes gjennom empirisk forskning i norsk skole

    Conformational and thermodynamic changes of the repressor/DNA operator complex upon monomerization shed new light on regulation mechanisms of bacterial resistance against β-lactam antibiotics

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    In absence of β-lactam antibiotics, BlaI and MecI homodimeric repressors negatively control the expression of genes involved in β-lactam resistance in Bacillus licheniformis and in Staphylococcus aureus. Subsequently to β-lactam presence, BlaI/MecI is inactivated by a single-point proteolysis that separates its N-terminal DNA-binding domain to its C-terminal domain responsible for its dimerization. Concomitantly to this proteolysis, the truncated repressor acquires a low affinity for its DNA target that explains the expression of the structural gene for resistance. To understand the loss of the high DNA affinity of the truncated repressor, we have determined the different dissociation constants of the system and solved the solution structure of the B. licheniformis monomeric repressor complexed to the semi-operating sequence OP1 of blaP (1/2OP1blaP) by using a de novo docking approach based on inter-molecular nuclear Overhauser effects and chemical-shift differences measured on each macromolecular partner. Although the N-terminal domain of the repressor is not subject to internal structural rearrangements upon DNA binding, the molecules adopt a tertiary conformation different from the crystallographic operator–repressor dimer complex, leading to a 30° rotation of the monomer with respect to a central axis extended across the DNA

    Site-specific perturbations of alpha-synuclein fibril structure by the Parkinson's disease associated mutations A53T and E46K.

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    PMCID: PMC3591419This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Parkinson's disease (PD) is pathologically characterized by the presence of Lewy bodies (LBs) in dopaminergic neurons of the substantia nigra. These intracellular inclusions are largely composed of misfolded α-synuclein (AS), a neuronal protein that is abundant in the vertebrate brain. Point mutations in AS are associated with rare, early-onset forms of PD, although aggregation of the wild-type (WT) protein is observed in the more common sporadic forms of the disease. Here, we employed multidimensional solid-state NMR experiments to assess A53T and E46K mutant fibrils, in comparison to our recent description of WT AS fibrils. We made de novo chemical shift assignments for the mutants, and used these chemical shifts to empirically determine secondary structures. We observe significant perturbations in secondary structure throughout the fibril core for the E46K fibril, while the A53T fibril exhibits more localized perturbations near the mutation site. Overall, these results demonstrate that the secondary structure of A53T has some small differences from the WT and the secondary structure of E46K has significant differences, which may alter the overall structural arrangement of the fibrils

    Amyloid prions in fungi

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    ABSTRACT Prions are infectious protein polymers that have been found to cause fatal diseases in mammals. Prions have also been identified in fungi (yeast and filamentous fungi), where they behave as cytoplasmic non-Mendelian genetic elements. Fungal prions correspond in most cases to fibrillary β-sheet-rich protein aggregates termed amyloids. Fungal prion models and, in particular, yeast prions were instrumental in the description of fundamental aspects of prion structure and propagation. These models established the “protein-only” nature of prions, the physical basis of strain variation, and the role of a variety of chaperones in prion propagation and amyloid aggregate handling. Yeast and fungal prions do not necessarily correspond to harmful entities but can have adaptive roles in these organisms.</jats:p

    Exploring TAR–RNA aptamer loop–loop interaction by X-ray crystallography, UV spectroscopy and surface plasmon resonance

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    In HIV-1, trans-activation of transcription of the viral genome is regulated by an imperfect hairpin, the trans-activating responsive (TAR) RNA element, located at the 5′ untranslated end of all viral transcripts. TAR acts as a binding site for viral and cellular proteins. In an attempt to identify RNA ligands that would interfere with the virus life-cycle by interacting with TAR, an in vitro selection was previously carried out. RNA hairpins that formed kissing-loop dimers with TAR were selected [Ducongé F. and Toulmé JJ (1999) RNA, 5:1605–1614]. We describe here the crystal structure of TAR bound to a high-affinity RNA aptamer. The two hairpins form a kissing complex and interact through six Watson–Crick base pairs. The complex adopts an overall conformation with an inter-helix angle of 28.1°, thus contrasting with previously reported solution and modelling studies. Structural analysis reveals that inter-backbone hydrogen bonds between ribose 2′ hydroxyl and phosphate oxygens at the stem-loop junctions can be formed. Thermal denaturation and surface plasmon resonance experiments with chemically modified 2′-O-methyl incorporated into both hairpins at key positions, clearly demonstrate the involvement of this intermolecular network of hydrogen bonds in complex stability

    A Peptidoglycan Fragment Triggers β-lactam Resistance in Bacillus licheniformis

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    To resist to β-lactam antibiotics Eubacteria either constitutively synthesize a β-lactamase or a low affinity penicillin-binding protein target, or induce its synthesis in response to the presence of antibiotic outside the cell. In Bacillus licheniformis and Staphylococcus aureus, a membrane-bound penicillin receptor (BlaR/MecR) detects the presence of β-lactam and launches a cytoplasmic signal leading to the inactivation of BlaI/MecI repressor, and the synthesis of a β-lactamase or a low affinity target. We identified a dipeptide, resulting from the peptidoglycan turnover and present in bacterial cytoplasm, which is able to directly bind to the BlaI/MecI repressor and to destabilize the BlaI/MecI-DNA complex. We propose a general model, in which the acylation of BlaR/MecR receptor and the cellular stress induced by the antibiotic, are both necessary to generate a cell wall-derived coactivator responsible for the expression of an inducible β-lactam-resistance factor. The new model proposed confirms and emphasizes the role of peptidoglycan degradation fragments in bacterial cell regulation

    NMR structure of the A730 loop of the Neurospora VS ribozyme: insights into the formation of the active site

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    The Neurospora VS ribozyme is a small nucleolytic ribozyme with unique primary, secondary and global tertiary structures, which displays mechanistic similarities to the hairpin ribozyme. Here, we determined the high-resolution NMR structure of a stem–loop VI fragment containing the A730 internal loop, which forms part of the active site. In the presence of magnesium ions, the A730 loop adopts a structure that is consistent with existing biochemical data and most likely reflects its conformation in the VS ribozyme prior to docking with the cleavage site internal loop. Interestingly, the A730 loop adopts an S-turn motif that is also present in loop B within the hairpin ribozyme active site. The S-turn appears necessary to expose the Watson–Crick edge of a catalytically important residue (A756) so that it can fulfill its role in catalysis. The A730 loop and the cleavage site loop of the VS ribozyme display structural similarities to internal loops found in the active site of the hairpin ribozyme. These similarities provided a rationale to build a model of the VS ribozyme active site based on the crystal structure of the hairpin ribozyme

    Cooperativity among Short Amyloid Stretches in Long Amyloidogenic Sequences

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    Amyloid fibrillar aggregates of polypeptides are associated with many neurodegenerative diseases. Short peptide segments in protein sequences may trigger aggregation. Identifying these stretches and examining their behavior in longer protein segments is critical for understanding these diseases and obtaining potential therapies. In this study, we combined machine learning and structure-based energy evaluation to examine and predict amyloidogenic segments. Our feature selection method discovered that windows consisting of long amino acid segments of ∼30 residues, instead of the commonly used short hexapeptides, provided the highest accuracy. Weighted contributions of an amino acid at each position in a 27 residue window revealed three cooperative regions of short stretch, resemble the β-strand-turn-β-strand motif in A-βpeptide amyloid and β-solenoid structure of HET-s(218–289) prion (C). Using an in-house energy evaluation algorithm, the interaction energy between two short stretches in long segment is computed and incorporated as an additional feature. The algorithm successfully predicted and classified amyloid segments with an overall accuracy of 75%. Our study revealed that genome-wide amyloid segments are not only dependent on short high propensity stretches, but also on nearby residues
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