1,720,968 research outputs found
Interaction between platinum complexes and a methionine motif found in copper transport proteins
No full textStructural Determinants of Cisplatin and Transplatin Binding to the Met-Rich Motif of Ctr1: A Computational Spectroscopy Approach
No full textThe cellular uptake of cisplatin and of other platinum-based drugs is mediated by the high-affinity copper transporter Ctr1. The eight-residue long peptide called Mets7 (MTGMKGMS) mimics one of extracellular methionine (Met)-rich motifs of Ctr1. It is an excellent model for investigating the interaction of platinum drugs with Ctr1 under in vitro and in vivo conditions. Some of us have shown that (i) Cisplatin loses all of its ligands upon reaction with Mets7 and the metal ion binds to the three Met residues and completes its coordination shell with a fourth ligand that can be a chloride or a water/hydroxyl oxygen. (ii) Transplatin loses only the chlorido ligands, which are replaced by Met residues. Here, we provide information on the structural determinants of cisplatin/Mets7 and transplatin/Mets7 adducts by computational methods. The predictions are validated against EXAFS, NMR, and CD spectra. While EXAFS gives information restricted to the metal coordination shell, NMR provides information extended to residue atoms around the coordination shell, and finally, CD provides information about the overall conformation of the peptide. This allows us to elucidate the different reaction modes of cisplatin and transplatin toward the peptide, as well as to propose the platinated peptides [PtX]+–(M*TGM*KGM*S) (X = Cl–, OH–) and trans[Pt(NH3)2]2+–(M*TGM*KGMS) as the most relevant species occurring in water solution
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Ubiquitin Stability and the Lys 63-Linked Polyubiquitination Site Are Compromised on Copper Binding
No full textSingle Cell Technology: a step forward to New Breeding Technologies
No full text1. Hypothesis
CRISPR-Cas application is boosting the development of the New Breeding Technologies (NBT) aimed at obtaining precise and specific mutations in shorter times with respect to conventional breeding. The project TRADING, funded by Fondazione Caritro, made possible the development of a new technology for the delivery of CRISPR-Cas in plant cells, by using single cells (Single Cell Technology or SCT). This technology allows to limit the extent of chimerism -frequently found in plants upon regeneration from tissues transformed via Agrobacterium or biolistic- as a whole plant would be regenerated starting by one transformed cell, thus securing both stability and homogeneity of its genetic pool.
2. Materials and methods
Both single cells with cell wall and protoplasts have been obtained by V.v. cv Crimson Seedless embryogenic callus. The plasmid containing the gene encoding the yellow fluorescent protein under the 35S promoter was internalized a) via particle bombardment in single cells with cell wall and b) via liposomes in protoplasts. Intracellular YFP expression was detected through confocal fluorescence microscopy. Both types of single cells were subjected to a regenerative process.
3. Results
Evidences of intracellular YFP expression suggest both the successful delivery of the vector as well as its expression and the cellular viability after treatment. Furthermore, in case of single cells with cell walls the regenerative phase has been successful and healthy plants were obtained.
4. Main conclusions
The Single Cell Technology appeared promising for grapevine applications aimed at achieving new grapevine clones by exploitation of the New Breeding Technologies such as genome editing. Tests for the delivery of CRISPR/Cas as ribonucleoprotein (RNPs), as well as regenerative tests from grapevine protoplasts, are currently ongoing
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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