3,505 research outputs found
The expression of pea (pisum sativum) vicilin in the yeast, Saccharomyces cerevisiae
This study has demonstrated and investigated the expression of a cDNA, coding for the pea seed storage protein vicilin, in the yeast, Saccharomyces cerevisiae. The cDNA was contained in the plasmid pLG1.63 and has been characterised and sequenced. The sequence showed that the cDNA coded for a 47KDa type of vicilin with a putative 24 amino-acid signal peptide, a proteolytic cleavage site and one glycosylation signal. The cDNA was cloned into two yeast expression vectors. The first utilised the GALIO promoter rendering expression of the cDNA inducible galactose, the construct was called pDUB2300. The second construct, pDUB2302, placed the cDNA under the control of the PGK promoter, rendering the cDNA constitutively expressed. When transformed into yeast, both constructs produced an immunoreactive vicilin species of M(_r) =49KDa. In the case of pDUB2302 the protein was produced at up to 5.5% of total cell protein. The protein was shown to be associated with a particulate fraction and displayed altered precipitation characteristics when compared with pea vicilin. By using tunicanydn and N-glycosidase, the protein was shown to be unglycosylated. Partial purification and (^35)S-methionine labelling demonstrated that the signal pep tide remained uncleaved. Cell fractionation studies indicated that vicilin was enriched in the yeast microsomal fraction, suggesting that vicilin was located in the EH. This was confirmed electron microscopy of immuno-gold labelled yeast which showed vicilin associated with the ER. The electron micrographs also suggested that a small proportion of the protein might be reaching thecolgi apparatus and the vacuole membrane. The presence of specific cleavage products on some western blots suggested that vicilin possessed a cleavage site for a yeast protease, though whether this was the same site as the pea proteolytic cleavage site was not determined. The pattern and nature of the expression of vicilin from this cDNA was discussed in the context of heterologous protein expression in yeast in general and plant storage protein expression in yeast in particular
'Learning together': Sharing international experience on new models of primary care
No abstract available
Cross-talk and interference enhance information capacity of a signaling pathway
A recurring motif in gene regulatory networks is transcription factors (TFs)
that regulate each other, and then bind to overlapping sites on DNA, where they
interact and synergistically control transcription of a target gene. Here, we
suggest that this motif maximizes information flow in a noisy network. Gene
expression is an inherently noisy process due to thermal fluctuations and the
small number of molecules involved. A consequence of multiple TFs interacting
at overlapping binding-sites is that their binding noise becomes correlated.
Using concepts from information theory, we show that in general a signaling
pathway transmits more information if 1) noise of one input is correlated with
that of the other, 2) input signals are not chosen independently. In the case
of TFs, the latter criterion hints at up-stream cross-regulation. We
demonstrate these ideas for competing TFs and feed-forward gene regulatory
modules, and discuss generalizations to other signaling pathways. Our results
challenge the conventional approach of treating biological noise as
uncorrelated fluctuations, and present a systematic method for understanding TF
cross-regulation networks either from direct measurements of binding noise, or
bioinformatic analysis of overlapping binding-sites.Comment: 28 pages, 5 figure
Plastid DNA sequences and oospore characters of some European taxa of Tolypella section Tolypella (Characeae) identify five clusters, including one new cryptic Tolypella taxon from Sardinia, but they do not coincide with current morphological descriptions
In Europe, the genus Tolypella (Characeae) comprises four to eight Tolypella taxa in sections Rothia and Tolypella that have been distinguished by vegetative morphology and gametangial characters such as antheridial size and oospore wall ornamentation. However, morphological differentiation is difficult in some cases due to overlapping and variable vegetative features, which in many cases are difficult to observe clearly. To clarify the taxonomic status of the five European taxa of Tolypella in section Tolypella, sequence data of the plastid genes atpB, rbcL and psbC for Tolypella glomerata (Desv.) Leonh., Tolypella hispanica Allen, Tolypella nidifica (O.F. MĂŒll.) A. Braun, Tolypella normaniana (Nordst.) Nordst. and Tolypella salina Cor. were combined with data on oospore morphology, including oospore wall ornamentation. Gene sequence data identified five distinct clusters, but they were not consistent with the morphologically identified five taxa. T. glomerata consisted of some of the samples morphologically identified as T. glomerata and seven samples of T. normaniana, while the remaining T. glomerata samples clustered with specimens of unclear affiliation (Tolypella sp.). We identified two clusters of T. hispanica within the European material: cluster T. hispanica I consisted of samples from various locations, whereas the second cluster (T. hispanica II) consisted of samples of T. hispanica from Sardinia Island. The remaining cluster consisted of all the specimens that had been determined as T. salina or T. nidifica in addition to two specimens of T. normaniana. Oospore morphology was most clearly distinguishable for T. glomerata. Oospore characteristics for all other taxa were not as informative but showed some geographical and/or environmentally influenced differences, especially for T. nidifica and T. salina. Our results suggest the need to further check the different taxonomy of Tolypella sect. Tolypella in which specimens normally identified as T. glomerata might be two different taxa, T. glomerata and an unidentified taxon; T. nidifica and T. salina are not separate taxa; T. normaniana is a diminutive variant of two different Tolypella taxa; and T. hispanica comprises two different taxa, one from the Mediterranean island Sardinia.publishedVersio
Aurora kinase A drives the evolution of resistance to third-generation EGFR inhibitors in lung cancer.
Although targeted therapies often elicit profound initial patient responses, these effects are transient due to residual disease leading to acquired resistance. How tumors transition between drug responsiveness, tolerance and resistance, especially in the absence of preexisting subclones, remains unclear. In epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma cells, we demonstrate that residual disease and acquired resistance in response to EGFR inhibitors requires Aurora kinase A (AURKA) activity. Nongenetic resistance through the activation of AURKA by its coactivator TPX2 emerges in response to chronic EGFR inhibition where it mitigates drug-induced apoptosis. Aurora kinase inhibitors suppress this adaptive survival program, increasing the magnitude and duration of EGFR inhibitor response in preclinical models. Treatment-induced activation of AURKA is associated with resistance to EGFR inhibitors in vitro, in vivo and in most individuals with EGFR-mutant lung adenocarcinoma. These findings delineate a molecular path whereby drug resistance emerges from drug-tolerant cells and unveils a synthetic lethal strategy for enhancing responses to EGFR inhibitors by suppressing AURKA-driven residual disease and acquired resistance
Improving Together: A National Framework for Quality and GP Clusters in Scotland
Improving together will complement the development of the Scottish national GP contract that sets out the role of GPs and their important contribution as clinical leaders and expert medical generalists working in a community setting. This framework will be reviewed by the Scottish Government and the Scottish General Practitioners Committee of the BMA on a periodic basis, attentive to feedback from those involved in delivering its intent. As such, it is a framework that will develop to its full potential over time, as elements of the transformation of primary care in Scotland create the capacity to do so
A multi-decade record of high quality fCO2 data in version 3 of the Surface Ocean CO2 Atlas (SOCAT)
The Surface Ocean CO2 Atlas (SOCAT) is a synthesis of quality-controlled fCO2 (fugacity of carbon dioxide) values for the global surface oceans and coastal seas with regular updates. Version 3 of SOCAT has 14.7 million fCO2 values from 3646 data sets covering the years 1957 to 2014. This latest version has an additional 4.6 million fCO2 values relative to version 2 and extends the record from 2011 to 2014. Version 3 also significantly increases the data availability for 2005 to 2013. SOCAT has an average of approximately 1.2 million surface water fCO2 values per year for the years 2006 to 2012. Quality and documentation of the data has improved. A new feature is the data set quality control (QC) flag of E for data from alternative sensors and platforms. The accuracy of surface water fCO2 has been defined for all data set QC flags. Automated range checking has been carried out for all data sets during their upload into SOCAT. The upgrade of the interactive Data Set Viewer (previously known as the Cruise Data Viewer) allows better interrogation of the SOCAT data collection and rapid creation of high-quality figures for scientific presentations. Automated data upload has been launched for version 4 and will enable more frequent SOCAT releases in the future. High-profile scientific applications of SOCAT include quantification of the ocean sink for atmospheric carbon dioxide and its long-term variation, detection of ocean acidification, as well as evaluation of coupled-climate and ocean-only biogeochemical models. Users of SOCAT data products are urged to acknowledge the contribution of data providers, as stated in the SOCAT Fair Data Use Statement. This ESSD (Earth System Science Data) âliving dataâ publication documents the methods and data sets used for the assembly of this new version of the SOCAT data collection and compares these with those used for earlier versions of the data collection (Pfeil et al., 2013; Sabine et al., 2013; Bakker et al., 2014). Individual data set files, included in the synthesis product, can be downloaded here: doi:10.1594/PANGAEA.849770. The gridded products are available here: doi:10.3334/CDIAC/OTG.SOCAT_V3_GRID
Narration and Focalization : A Cognitivist and an Unnaturalist, Made Strange
Any new narratological theory faces the test of being applicable to much-analyzedclassics of prose fiction and of yielding new insights into narratives that have served as textbook examples of narrative strategies for decades. This essay is a constructed dialogue between imaginary narratologists who are paradigmatic proponents of two schools of thought in postclassical narratology: the cognitive and the unnatural. The two narratologists juxtapose their respective concepts and methodologies in an analysis of William Golding's late modernist classic The Inheritors, especially the narrative dynamics of "alien" Neanderthal focalization versus "naturalizing" Homo sapiens narration. Ultimately, The Inheritors reminds the cognitivist of how language-bound the readerly effects of estrangement and integration in internal focalization can be. Conversely, the same novel serves as an example for the unnaturalist of the paradoxical necessity for perceptual and emotional familiarization in our attempts to understand fundamental alterity. The parameters of cognitive and unnatural narratology may seem divergent at the outset, but in this essay their representatives find a common ground in an estranging reading of the enactive immersion in The Inheritors. Here the extraordinary embodiedness of the Neanderthal focalization is a key to a literary-allegorical reading of the Neanderthal mind as imagined by Golding. This reading, accomplished through a constructed debate between two paradigms, reflects the actual positions of the authors of this essay: Makela and Polvinen are both proponents of an approach that acknowledges the inherent syntheticity and linguistic overdeterminedness of a literary narrative as well as its "natural" enactivist pull toward bodily immersion.Peer reviewe
Double hadron leptoproduction in the nuclear medium
First measurement of double-hadron production in deep-inelastic scattering
has been measured with the HERMES spectrometer at HERA using a 27.6 GeV
positron beam with deuterium, nitrogen, krypton and xenon targets. The
influence of the nuclear medium on the ratio of double-hadron to single-hadron
yields has been investigated. Nuclear effects are clearly observed but with
substantially smaller magnitude and reduced -dependence compared to
previously measured single-hadron multiplicity ratios. The data are in fair
agreement with models based on partonic or pre-hadronic energy loss, while they
seem to rule out a pure absorptive treatment of the final state interactions.
Thus, the double-hadron ratio provides an additional tool for studying
modifications of hadronization in nuclear matter
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