1,721,088 research outputs found
The role of ABC1K7 and ABC1K8, two ABC1K kinases of Arabidopsis thaliana
Full text linkThe activity of bc1 complex kinases (ABC1K) belong to a large group of atypical protein kinases found in prokaryotes and eukaryotes. In bacteria and mitochondria, ABC1K kinases are involved in the respiratory pathway, being necessary for the synthesis of the coenzyme Q. In chloroplasts, ABC1K proteins play a role in prenylquinone synthesis and stress responses, but their precise function remains unclear. A functional characterization was carried out for ABC1K7 and ABC1K8, two ABC1K proteins of the Arabidopsis thaliana plastome. The comparison of abc1k7 and abc1k8 mutants, abc1k7/abc1k8 double mutant and wild-type plants revealed a reduction in plastidial ironcontaining proteins of the Cytb6f complex in the mutants. Iron uptake from soil is not hampered in mutant lines, suggesting that ABC1K7 and ABC1K8 affect iron distribution within the chloroplast. Moreover, mutant plants accumulated more ferritin and superoxide, and showed reduced tolerance to reactive oxygen species (ROS). Because ROS take part in abscisic acid (ABA) signaling, we investigated the relation between ABA and ABC1K7 and ABC1K8 and found that both genes were upregulated by ABA treatment, while expression of several ABA-responsive genes resulted affected in mutants. Moreover, analyzing ABA-mediated processes, we determined that germination was more affected by ABA treatment and osmotic and salt stress in the single and double mutants than in wild-type plants. Stomatal aperture was also reduced in the mutants under standard growth conditions and was not further reduced by exogenous ABA application. Furthermore, ABA-induced senescence symptoms were more severe in the leaves of the mutants compared to wild type leaves. Taken together, these data suggest that ABC1K7 and ABC1K8 probably act in signaling pathways that influence responses to ROS production and oxidative stress, such as ABA signaling, probably by influencing the cellular redox state and chloroplast lipid metabolism
THE ROLE OF THE ARABIDOPSIS THALIANA ATYPICAL KINASES ABC1K2 AND ABC1K9 IN STRESS RESPONSES
No full textThe ABC1K protein kinases (activity of bc1 complex kinases) are a large family of proteins with multiple roles in the regulation of respiration and oxidative stress tolerance. In plants they regulate diverse physiological processes in the chloroplasts and mitochondria, but their precise functions are poorly defined. In this work the functional characterization of the chloroplast Arabidopsis thaliana ABC1K2 and ABC1K9 proteins is carried out. To characterize the function of the two proteins, A. thaliana knock-out mutant lines that lack ABC1K2 or ABC1K9 proteins are considered. Under standard growth conditions, abc1k2 and abc1k9 mutant plants do not show morphological or developmental abnormalities if compared to wild type. Pigment analysis reveals a reduced total chlorophyll content and Chla/b ratio in abc1k2 and abc1k9 old leaves. Analysis of ultrathin sections of leaves with transmission electron microscopy does not show any significant difference in the chloroplast ultrastructure between wild type and mutant plants. Interestingly, in abc1k2 and abc1k9 plants plastoglobules with a reduced diameter are associated with thylakoids. Analysis of the photosynthetic performance demonstrates no differences in the major photosynthetic parameters between wild type and mutant plants. Since other ABC1K proteins are involved in plant response to oxidative stress, the effect of oxidative stress on abc1k2 and abc1k9 mutant plants is considered. When plants were grown in the presence of hydrogen peroxide, both abc1k2 and abc1k9 mutants show an increased root length in comparison to wild type. Transcription levels of SOD genes and APX1 are down-regulated in abc1k2 mutant, while they result up-regulated in abc1k9. The level of superoxide anion radical staining is more evident in wild type plants than in abc1k2 and abc1k9 mutants. Because reactive oxygen species take part in ABAmediated processes, the functions of ABC1K2 and ABC1K9 during germination are investigated. Germination is more severely affected by ABA, osmotic stress and salt stress in abc1k2 and abc1k9 mutants. These results suggest that ABC1K2 and ABC1K9 might be involved in the cross-talk between ABA and ROS signallin
Correlation between psychometric and biological parameters in anorexic and bulimic patients during and after intensive day-hospital treatment
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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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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