1,721,024 research outputs found
Protein mislocalization in plant cells using a GFP-binding chromobody
No full textP>A key challenge in cell biology is to directly link protein localization to function. The green fluorescent protein (GFP)-binding protein, GBP, is a 13-kDa soluble protein derived from a llama heavy chain antibody that binds with high affinity to GFP as well as to some GFP variants such as yellow fluorescent protein (YFP). A GBP fusion to the red fluorescent protein (RFP), a molecule termed a chromobody, was previously used to trace in vivo the localization of various animal antigens. In this study, we extend the use of chromobody technology to plant cells and develop several applications for the in vivo study of GFP-tagged plant proteins. We took advantage of Agrobacterium tumefaciens-mediated transient expression assays (agroinfiltration) and virus expression vectors (agroinfection) to express functional GBP:RFP fusion (chromobody) in the model plant Nicotiana benthamiana. We showed that the chromobody is effective in binding GFP- and YFP-tagged proteins in planta. Most interestingly, GBP:RFP can be applied to interfere with the function of GFP fusion protein and to mislocalize (trap) GFP fusions to the plant cytoplasm in order to alter the phenotype mediated by the targeted proteins. Chromobody technology, therefore, represents a new alternative technique for protein interference that can directly link localization of plant proteins to in vivo function.</p
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
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
Impact of Emerging SARS-CoV-2 Variants on Humoral Immune Responses of COVID-19-Infected and Vaccinated Individuals
No full textThe COVID-19 pandemic caused by the previously unknown SARS-CoV-2 presented the scientific community with the challenging task of understanding the basic properties of the virus under rapidly evolving and changing circumstances, in order to pave the way for effective therapies and vaccines.
To assess the humoral immune response to SARS-CoV-2, we developed and validated a multiplex serological immunoassay, MULTICOV-AB, for the reliable detection of antibodies against SARS-CoV-2 key antigens including the receptor binding domain (RBD) and nucleocapsid, demonstrating high sensitivity and specificity for the classification of infection. As the seroprevalence of SARS-CoV-2 in the population continuously increased and vaccination campaigns progressed, the quality of the antibody response, including longevity and immune protection, became the focus of research. This has been reinforced by the continuous emergence of new SARS-CoV-2 variants that differ in their ability to evade existing immune responses and thus make reinfection more likely.
Therefore, we have developed RBDCoV-ACE2, a multiplex surrogate neutralisation assay that investigates the presence of neutralising antibodies (NAbs) that interfere with the binding of the SARS-CoV-2 RBD to the host cellular receptor angiotensin-converting enzyme 2 (ACE2), which is equivalent to preventing infection in vivo.
Using both assays, we were able to show that variants with the E484K mutation, for example Beta, Gamma and Theta, are more likely to evade existing humoral immune responses, as antibodies formed against the RBD of the wild-type virus exhibited up to 14-fold lower ACE2 binding inhibition against these variants. Furthermore, we were able to compare vaccination regimens and show that mRNA-based vaccination led to a superior humoral immune response compared to homologous vector-based vaccine regimens. We were able to show that the long-term humoral immune response to SARS-CoV-2 infection lasts longer in children than in adults, even after asymptomatic infection. With the emergence of the highly mutated Omicron variants, we were able to show that both antigen binding and ACE2 binding inhibition of antibodies induced by vaccination or/and infection were greatly reduced, with booster doses and breakthrough infections causing a significant increase in both levels. This reduction in neutralising capacity was particularly noticeable in serum from immunocompromised individuals, such as hemodialysis or inflammatory bowel disease (IBD) patients, where we were able to contribute indications for future vaccination strategies. Both MULTICOV-AB and RBDCoV-ACE2 continue to provide valuable knowledge about the humoral immune response to novel emerging SARS-CoV-2 variants
Nanobody
No full textNanobodies have become outstanding tools for biomedical research, diagnostics and therapy. Recent advances in the identification and functionalization of target-specific nanobodies now make nanobody-based approaches broadly available to many researches in the field. This book provides a compilation of original research articles and comprehensive reviews covering important and up to date aspects of research on nanobodies and their applications for immunoassays, proteomics, protein crystallization and in vitro and in vivo imaging
Nanobody
Full text linkNanobodies have become outstanding tools for biomedical research, diagnostics and therapy. Recent advances in the identification and functionalization of target-specific nanobodies now make nanobody-based approaches broadly available to many researches in the field. This book provides a compilation of original research articles and comprehensive reviews covering important and up to date aspects of research on nanobodies and their applications for immunoassays, proteomics, protein crystallization and in vitro and in vivo imaging
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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