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71.
Removal of naturally grown human biofilm with an atmospheric pressure plasma jet: An in‐vitro study 下载免费PDF全文
Lukasz Jablonowski Katja Fricke Rutger Matthes Birte Holtfreter Rabea Schlüter Thomas von Woedtke Klaus‐Dieter Weltmann Thomas Kocher 《Journal of biophotonics》2017,10(5):718-726
The removal of biofilm is a prerequisite for a successful treatment of biofilm‐associated diseases. In this study, we compared the feasibility of an atmospheric pressure plasma device with a sonic powered brush to remove naturally grown supragingival biofilm from extracted teeth. Twenty‐four periodontally hopeless teeth were extracted. Argon jet plasma with an oxygen admixture of 1 vol% and a sonically driven brush were used to remove biofilm with application times of 60 s, 180 s and 300 s. The treatment efficiency was assessed with light microscopy, scanning electron microscopy (SEM) and X‐ray photoelectron spectroscopy (XPS). The highest biofilm removal rate was observed after an application time of 180 s/300 s with the sonic brush (80.4%/86.2%), plasma (75.5%/89.0%). These observations were confirmed by SEM. According to XPS analysis, plasma treatment decreased the amount of carbon and nitrogen, indicative of an extensive removal of proteins. Plasma treatment of naturally grown biofilm resulted in an effective cleaning of the tooth surface and was comparable to mechanical treatment. Treatment time had a significant influence on plaque reduction. These results showed that plasma could be a useful adjuvant treatment modality in cases where biofilm removal or reduction plays a decisive role, such as periodontitis and peri‐implantitis.
72.
Jeppe Reitan Andersen Imad Zein Gerhard Wenzel Birte Darnhofer Joachim Eder Milena Ouzunova Thomas Lübberstedt 《BMC plant biology》2008,8(1):2
Background
Forage quality of maize is influenced by both the content and structure of lignins in the cell wall. Biosynthesis of monolignols, constituting the complex structure of lignins, is catalyzed by enzymes in the phenylpropanoid pathway. 相似文献73.
Maeda K Hägglund P Finnie C Svensson B Henriksen A 《Protein science : a publication of the Protein Society》2008,17(6):1015-1024
H-type thioredoxins (Trxs) constitute a particularly large Trx sub-group in higher plants. Here, the crystal structures are determined for the two barley Trx h isoforms, HvTrxh1 and HvTrxh2, in the partially radiation-reduced state to resolutions of 1.7 A, and for HvTrxh2 in the oxidized state to 2.0 A. The two Trxs have a sequence identity of 51% and highly similar fold and active-site architecture. Interestingly, the four independent molecules in the crystals of HvTrxh1 form two relatively large and essentially identical protein-protein interfaces. In each interface, a loop segment of one HvTrxh1 molecule is positioned along a shallow hydrophobic groove at the primary nucleophile Cys40 of another HvTrxh1 molecule. The association mode can serve as a model for the target protein recognition by Trx, as it brings the Met82 Cgamma atom (gamma position as a disulfide sulfur) of the bound loop segment in the proximity of the Cys40 thiol. The interaction involves three characteristic backbone-backbone hydrogen bonds in an antiparallel beta-sheet-like arrangement, similar to the arrangement observed in the structure of an engineered, covalently bound complex between Trx and a substrate protein, as reported by Maeda et al. in an earlier paper. The occurrence of an intermolecular salt bridge between Glu80 of the bound loop segment and Arg101 near the hydrophobic groove suggests that charge complementarity plays a role in the specificity of Trx. In HvTrxh2, isoleucine corresponds to this arginine, which emphasizes the potential for specificity differences between the coexisting barley Trx isoforms. 相似文献
74.
The accurate modeling of metal coordination geometries plays an important role for structure-based drug design applied to metalloenzymes. For the development of a new metal interaction model, we perform a statistical analysis of metal interaction geometries that are relevant to protein-ligand complexes. A total of 43,061 metal sites of the Protein Data Bank (PDB), containing amongst others magnesium, calcium, zinc, iron, manganese, copper, cadmium, cobalt, and nickel, were evaluated according to their metal coordination geometry. Based on statistical analysis, we derived a model for the automatic calculation and definition of metal interaction geometries for the purpose of molecular docking analyses. It includes the identification of the metal-coordinating ligands, the calculation of the coordination geometry and the superposition of ideal polyhedra to identify the optimal positions for free coordination sites. The new interaction model was integrated in the docking software FlexX and evaluated on a data set of 103 metalloprotein-ligand complexes, which were extracted from the PDB. In a first step, the quality of the automatic calculation of the metal coordination geometry was analyzed. In 74% of the cases, the correct prediction of the coordination geometry could be determined on the basis of the protein structure alone. Secondly, the new metal interaction model was tested in terms of predicting protein-ligand complexes. In the majority of test cases, the new interaction model resulted in an improved docking accuracy of the top ranking placements. 相似文献
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77.
Birte Eleen Wassmuth Peter Stoll Teja Tscharntke Carsten Thies 《Perspectives in Plant Ecology, Evolution and Systematics》2009,11(2):127-135
European agri-environment schemes encourage farmers to establish sown field margin strips to protect and enhance wild plant diversity. However, plant diversity in such wild plant sowings based on seed mixtures is often low due to the high competitiveness of few, common species. Here we analysed whether intraspecific aggregation could enhance the performance of less competitive species, and how plant performance is influenced by the number of species in a mixture. We focused on inter- and intraspecific competition between six agricultural wild plant species (Centaurea cyanus, Calendula arvensis, Melilotus officinalis, Poa annua, Bromus mollis, Medicago lupulina), and tested (i) two different seeding patterns (intraspecifically aggregated vs. randomly dispersed) and (ii) three different species mixtures (monocultures, three-species, and six-species mixtures). Plant performance was measured in terms of number of individuals, biomass per individual, and biomass per m2. Intraspecific aggregation resulted in higher numbers of individuals of all species, while mixtures generated lower numbers of individuals. The performance of plant species differed depending on their position in the competitive hierarchy. Competitively weak species suffered much less from intraspecific than interspecific competition in terms of biomass, and the competitively weakest species became even excluded in the most species rich and randomly dispersed sowings with high interspecific competition. In conclusion, the performance of wild plant species was influenced by both seeding pattern and number of species in a mixture. Intraspecific aggregation enabled the coexistence of competitively weak species by reducing interspecific competitive exclusion processes. Consequently, agri-environmental schemes designed to preserve and enhance biodiversity should consider small-scale processes influencing the distribution and abundance of plants, and develop new agricultural sowing technologies to cultivate competitively weak and endangered wild plant species. 相似文献
78.
Christine Finnie Merethe Bagge Torben Steenholdt Ole Østergaard Kristian Sass Bak-Jensen Gunter Backes Anaïs Jensen Henriette Giese Jørgen Larsen Peter Roepstorff Birte Svensson 《Functional & integrative genomics》2009,9(1):135-143
Two-dimensional gel electrophoresis was used to screen spring barley cultivars for differences in seed protein profiles. In
parallel, 72 microsatellite (simple sequence repeat (SSR)) markers and 11 malting quality parameters were analysed for each
cultivar. Over 60 protein spots displayed cultivar variation, including peroxidases, serpins and proteins with unknown functions.
Cultivars were clustered based on the spot variation matrix. Cultivars with superior malting quality grouped together, indicating
malting quality to be more closely correlated with seed proteomes than with SSR profiles. Mass spectrometry showed that some
spot variations were caused by amino acid differences encoded by single nucleotide polymorphisms (SNPs). Coding SNPs were
validated by mass spectrometry, expressed sequence tag and 2D gel data. Coding SNPs can alter function of affected proteins
and may thus represent a link between cultivar traits, proteome and genome. Proteome analysis of doubled haploid lines derived
from a cross between a malting (Scarlett) and a feed cultivar (Meltan) enabled genetic localisation of protein phenotypes
represented by 48 spot variations, involving e.g. peroxidases, serpins, α-amylase/trypsin inhibitors, peroxiredoxin and a
small heat shock protein, in relation to markers on the chromosome map.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
79.
Maeda K Hägglund P Finnie C Svensson B Henriksen A 《Structure (London, England : 1993)》2006,14(11):1701-1710
Thioredoxin is ubiquitous and regulates various target proteins through disulfide bond reduction. We report the structure of thioredoxin (HvTrxh2 from barley) in a reaction intermediate complex with a protein substrate, barley alpha-amylase/subtilisin inhibitor (BASI). The crystal structure of this mixed disulfide shows a conserved hydrophobic motif in thioredoxin interacting with a sequence of residues from BASI through van der Waals contacts and backbone-backbone hydrogen bonds. The observed structural complementarity suggests that the recognition of features around protein disulfides plays a major role in the specificity and protein disulfide reductase activity of thioredoxin. This novel insight into the function of thioredoxin constitutes a basis for comprehensive understanding of its biological role. Moreover, comparison with structurally related proteins shows that thioredoxin shares a mechanism with glutaredoxin and glutathione transferase for correctly positioning substrate cysteine residues at the catalytic groups but possesses a unique structural element that allows recognition of protein disulfides. 相似文献
80.
Elisa Monzon-Casanova Birte Steiniger Stefanie Schweigle Holger Clemen Daniela Zdzieblo Lisa Starick Ingrid Müller Chyung-Ru Wang Sara Rhost Susanna Cardell Elwira Pyz Thomas Herrmann 《PloS one》2010,5(9)