The Novel CXCL12γ Isoform Encodes an Unstructured Cationic Domain Which Regulates Bioactivity and Interaction with Both Glycosaminoglycans and CXCR4

International audienceBACKGROUND: CXCL12alpha, a chemokine that importantly promotes the oriented cell migration and tissue homing of many cell types, regulates key homeostatic functions and pathological processes through interactions with its cognate receptor (CXCR4) and heparan sulfate (HS). The alternative splicing of the cxcl12 gene generates a recently identified isoform, CXCL12gamma, which structure/function relationships remain unexplored. The high occurrence of basic residues that characterize this isoform suggests however that it could feature specific regulation by HS. METHODOLOGY/PRINCIPAL FINDINGS: Using surface plasmon resonance and NMR spectroscopy, as well as chemically and recombinantly produced chemokines, we show here that CXCL12gamma first 68 amino acids adopt a structure closely related to the well described alpha isoform, followed by an unfolded C-terminal extension of 30 amino acids. Remarkably, 60 % of these residues are either lysine or arginine, and most of them are clustered in typical HS binding sites. This provides the chemokine with the highest affinity for HP ever observed (Kd = 0.9 nM), and ensures a strong retention of the chemokine at the cell surface. This was due to the unique combination of two cooperative binding sites, one strictly required, found in the structured domain of the protein, the other one being the C-terminus which essentially functions by enhancing the half life of the complexes. Importantly, this peculiar C-terminus also regulates the balance between HS and CXCR4 binding, and consequently the biological activity of the chemokine. CONCLUSIONS/SIGNIFICANCE: Together these data describe an unusual binding process that gives rise to an unprecedented high affinity between a chemokine and HS. This shows that the gamma isoform of CXCL12, which features unique structural and functional properties, is optimized to ensure its strong retention at the cell surface. Thus, depending on the chemokine isoform to which it binds, HS could differentially orchestrate the CXCL12 mediated directional cell kinesis

Structural Basis for the Association of MAP6 Protein with Microtubules and Its Regulation by Calmodulin: Microtubule and calmodulin binding on Mn modules of MAP6

International audienceMicrotubules are highly dynamic αβ-tubulin polymers. In vitro and in living cells, microtubules are most often cold- and nocodazole-sensitive. When present, the MAP6/STOP family of proteins protects microtubules from cold- and nocodazole-induced depolymerization but the molecular and structure determinants by which these proteins stabilize microtubules remain under debate. We show here that a short protein fragment from MAP6-N, which encompasses its Mn1 and Mn2 modules (MAP6(90-177)), recapitulates the function of the full-length MAP6-N protein toward microtubules, i.e. its ability to stabilize microtubules in vitro and in cultured cells in ice-cold conditions or in the presence of nocodazole. We further show for the first time, using biochemical assays and NMR spectroscopy, that these effects result from the binding of MAP6(90-177) to microtubules with a 1:1 MAP6(90-177):tubulin heterodimer stoichiometry. NMR data demonstrate that the binding of MAP6(90-177) to microtubules involve its two Mn modules but that a single one is also able to interact with microtubules in a closely similar manner. This suggests that the Mn modules represent each a full microtubule binding domain and that MAP6 proteins may stabilize microtubules by bridging tubulin heterodimers from adjacent protofilaments or within a protofilament. Finally, we demonstrate that Ca(2+)-calmodulin competes with microtubules for MAP6(90-177) binding and that the binding mode of MAP6(90-177) to microtubules and Ca(2+)-calmodulin involves a common stretch of amino acid residues on the MAP6(90-177) side. This result accounts for the regulation of microtubule stability in cold condition by Ca(2+)-calmodulin

"Preferred reading" of Legal Texts

In the 1970s, British cultural theorist Stuart Hall introduced a concept known as preferred reading. It combines the ideological influence of mass media and dominant ways of understanding any text. This article focuses on mass media as a source of ideological background or context of legal interpretation and of any reading of legal texts. Law operates in culture and culture represents limitations in the law, according to the needs of dominant ideology. Culture introduces structures of domination which manipulate law. An important role is also given to popular culture and mass culture. These parts of the culture industry create borders in which the recipients (audience) think of law. Through mass media – rather than through other channels – dominant ideology infiltrates law. Legal consciousness is formed by dominant cultural frames formed by dominant ideology. Through this formation of mass media, law becomes a commodity. It shares the same values or contents as that of cultural industry and is the place where the theory of preferred reading can be introduced. According to the aforementioned theory, there are methods of interpretation that are more accurate than others are. This is simply because they lead to a result that is more preferred by ‘common opinion’ disseminated by mass culture.V roce 1970, britský kulturní teoretik Stuart Hall představil koncept známý jako preferovaného čtení. Ten v sobě spojuje ideologický vliv masových médií a dominantní způsoby chápání jakéhokoli textu. Tento článek se zaměřuje masová média jako zdroj ideologického pozadí nebo kontextu právního výkladu. Právo působí v kultuře a kultura představuje omezení právo dle potřeb dominantní ideologie. Kultura vytváří struktury dominace, které manipulují právem. Důležitou roli také sehrává populární a masová kultura. Tyto části kulturního průmyslu vytváří hranice, ve kterých příjemci (publikum) uvažují o právu. Prostřednictvím masových médií - spíše než prostřednictvím jiných kanálů - dominantní ideologie infiltruje právo. Právní vědomí je tvořeno dominantními kulturními rámci vytvořenými dominantní ideologií. Prostřednictvím této formace vytvářené masovými médii se právo stává komoditou. Sdílí proto stejné hodnoty, nebo obsah jaké definuje kulturní průmysl. Proto lze i v právním kontextu uvažovat o tzv. preferovaném čtení. Proto lze identifikovat paradigmata výkladu, které jsou mnohem "použeitelnější" než jiné, protože vedou k očekávaným výsledkům. K výsledkům, které odpovídají očekávání masového publika.In the 1970s, British cultural theorist Stuart Hall introduced a concept known as preferred reading. It combines the ideological influence of mass media and dominant ways of understanding any text. This article focuses on mass media as a source of ideological background or context of legal interpretation and of any reading of legal texts. Law operates in culture and culture represents limitations in the law, according to the needs of dominant ideology. Culture introduces structures of domination which manipulate law. An important role is also given to popular culture and mass culture. These parts of the culture industry create borders in which the recipients (audience) think of law. Through mass media – rather than through other channels – dominant ideology infiltrates law. Legal consciousness is formed by dominant cultural frames formed by dominant ideology. Through this formation of mass media, law becomes a commodity. It shares the same values or contents as that of cultural industry and is the place where the theory of preferred reading can be introduced. According to the aforementioned theory, there are methods of interpretation that are more accurate than others are. This is simply because they lead to a result that is more preferred by ‘common opinion’ disseminated by mass culture

Regulating Two-Sided Markets: An Empirical Investigation

Two-sided market theory predicts that platforms may subsidize the participation of one type of agent by extracting surplus from another type to internalize indirect network externalities. However, few empirical studies exist to evaluate the impact of government intervention in these markets. We use confidential bank-level data to study the impact of government-encouraged fee reductions for payment card services when merchant acceptance is not complete. We find that consumer and merchant welfare improved when the interchange fees, transfers among banks, were reduced. Furthermore, bank revenues increased because the increase in the number of transactions offset the decrease in the per-transaction revenue

PhylArray: phylogenetic probe design algorithm for microarray

International audienceMOTIVATION: Microbial diversity is still largely unknown in most environments, such as soils. In order to get access to this microbial 'black-box', the development of powerful tools such as microarrays are necessary. However, the reliability of this approach relies on probe efficiency, in particular sensitivity, specificity and explorative power, in order to obtain an image of the microbial communities that is close to reality. RESULTS: We propose a new probe design algorithm that is able to select microarray probes targeting SSU rRNA at any phylogenetic level. This original approach, implemented in a program called 'PhylArray', designs a combination of degenerate and non-degenerate probes for each target taxon. Comparative experimental evaluations indicate that probes designed with PhylArray yield a higher sensitivity and specificity than those designed by conventional approaches. Applying the combined PhyArray/GoArrays strategy helps to optimize the hybridization performance of short probes. Finally, hybridizations with environmental targets have shown that the use of the PhylArray strategy can draw attention to even previously unknown bacteria

Comparison of user groups' perspectives of barriers and facilitators to implementing electronic health records: a systematic review

<p>Abstract</p> <p>Background</p> <p>Electronic health record (EHR) implementation is currently underway in Canada, as in many other countries. These ambitious projects involve many stakeholders with unique perceptions of the implementation process. EHR users have an important role to play as they must integrate the EHR system into their work environments and use it in their everyday activities. Users hold valuable, first-hand knowledge of what can limit or contribute to the success of EHR implementation projects. A comprehensive synthesis of EHR users' perceptions is key to successful future implementation. This systematic literature review was aimed to synthesize current knowledge of the barriers and facilitators influencing shared EHR implementation among its various users.</p> <p>Methods</p> <p>Covering a period from 1999 to 2009, a literature search was conducted on nine electronic databases. Studies were included if they reported on users' perceived barriers and facilitators to shared EHR implementation, in healthcare settings comparable to Canada. Studies in all languages with an empirical study design were included. Quality and relevance of the studies were assessed. Four EHR user groups were targeted: physicians, other health care professionals, managers, and patients/public. Content analysis was performed independently by two authors using a validated extraction grid with pre-established categorization of barriers and facilitators for each group of EHR users.</p> <p>Results</p> <p>Of a total of 5,695 potentially relevant publications identified, 117 full text publications were obtained after screening titles and abstracts. After review of the full articles, 60 publications, corresponding to 52 studies, met the inclusion criteria. The most frequent adoption factors common to all user groups were design and technical concerns, ease of use, interoperability, privacy and security, costs, productivity, familiarity and ability with EHR, motivation to use EHR, patient and health professional interaction, and lack of time and workload. Each user group also identified factors specific to their professional and individual priorities.</p> <p>Conclusions</p> <p>This systematic review presents innovative research on the barriers and facilitators to EHR implementation. While important similarities between user groups are highlighted, differences between them demonstrate that each user group also has a unique perspective of the implementation process that should be taken into account.</p

Multi-level analysis of electronic health record adoption by health care professionals: A study protocol

<p>Abstract</p> <p>Background</p> <p>The electronic health record (EHR) is an important application of information and communication technologies to the healthcare sector. EHR implementation is expected to produce benefits for patients, professionals, organisations, and the population as a whole. These benefits cannot be achieved without the adoption of EHR by healthcare professionals. Nevertheless, the influence of individual and organisational factors in determining EHR adoption is still unclear. This study aims to assess the unique contribution of individual and organisational factors on EHR adoption in healthcare settings, as well as possible interrelations between these factors.</p> <p>Methods</p> <p>A prospective study will be conducted. A stratified random sampling method will be used to select 50 healthcare organisations in the Quebec City Health Region (Canada). At the individual level, a sample of 15 to 30 health professionals will be chosen within each organisation depending on its size. A semi-structured questionnaire will be administered to two key informants in each organisation to collect organisational data. A composite adoption score of EHR adoption will be developed based on a Delphi process and will be used as the outcome variable. Twelve to eighteen months after the first contact, depending on the pace of EHR implementation, key informants and clinicians will be contacted once again to monitor the evolution of EHR adoption. A multilevel regression model will be applied to identify the organisational and individual determinants of EHR adoption in clinical settings. Alternative analytical models would be applied if necessary.</p> <p>Results</p> <p>The study will assess the contribution of organisational and individual factors, as well as their interactions, to the implementation of EHR in clinical settings.</p> <p>Conclusions</p> <p>These results will be very relevant for decision makers and managers who are facing the challenge of implementing EHR in the healthcare system. In addition, this research constitutes a major contribution to the field of knowledge transfer and implementation science.</p