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Gram-positive commensal bacteria for mucosal vaccine delivery.
No full textTo avoid the use of engineered pathogens for vaccine delivery, systems have been developed that allow the expression of heterologous antigens in commensal Gram-positive bacteria. In some cases, both a serum IgG and secretory IgA response are induced to the recombinant protein after vaccination, verifying the validity of the approach. These live recombinant bacteria may be used in the future to introduce a protective immune response to pathogenic microorganisms after mucosal colonization
Expression of M6 protein gene of Streptococcus pyogenes in Streptococcus gordonii after chromosomal integration and transcriptional fusion
No full textExpression of foreign proteins on gram-positive commensal bacteria for mucosal vaccine delivery.
No full textNon-pathogenic Gram-positive oral commensal bacteria expressing recombinant fusion proteins on their cell surface have been successfully used to raise both a mucosal and a systemic immune response to foreign antigens while colonizing the oropharynx. In this system, fusion-protein vaccines are delivered and anchored to the surface of a commensal, which occupies the mucosal niche invaded by a particular pathogen. Surface expression of these foreign proteins is achieved by exploiting the common mechanism employed by Gram-positive bacteria for translocating and anchoring proteins to the cell surface. The process offers a safe alternative to the use of engineered pathogens as live vaccine delivery vehicles
Mucosal and systemic immune responses to a recombinant protein expressed on the surface of the oral commensal bacterium Streptococcus gordonii after oral colonization
No full textTo circumvent the need to engineer pathogenic microorganisms as live vaccine-delivery vehicles, a system was developed which allowed for the stable expression of a wide range of protein antigens on the surface of Gram-positive commensal bacteria. The human oral commensal Streptococcus gordonii was engineered to surface express a 204-amino acid allergen from hornet venom (Ag5.2) as a fusion with the anchor region of the M6 protein of Streptococcus pyogenes. The immunogenicity of the M6-Ag5.2 fusion protein was assessed in mice inoculated orally and intranasally with a single dose of recombinant bacteria, resulting in the colonization of the oral/pharyngeal mucosa for 10-11 weeks. A significant increase of Ag5.2-specific IgA with relation to the total IgA was detected in saliva and lung lavages when compared with mice colonized with wild-type S. gordonii. A systemic IgG response to Ag5.2 was also induced after oral colonization. Thus, recombinant Gram-positive commensal bacteria may be a safe and effective way of inducing a local and systemic immune response
Expression of M6 protein gene of Streptococcus pyogenes in Streptococcus gordonii after chromosomal integration and transcriptional fusion
No full textThe M6 protein of Streptococcus pyogenes was expressed on the cell surface and secreted in Streptococcus gordonii Challis (formerly Streptococcus sanguis) after chromosomal integration of a promoterless M6 protein gene (emm-6.1). The ermC gene, conferring resistance to erythromycin, was cloned downstream of emm-6.1, within the same ClaI fragment. The initiation codon of emm-6.1 was 19 bp downstream of a ClaI site, so that ClaI cleavage would leave the gene promoterless. The ClaI fragment containing the promoterless emm-6.1 and ermC was ligated in vitro with a ClaI digest of S. gordonii chromosomal DNA. Random chromosomal integration of the heterologous DNA was obtained by using the ligation mixture to transform the naturally competent S. gordonii Challis. Twenty-eight percent of transformants selected for erythromycin resistance also expressed M6. Among the best M6 producers, 10 clones were selected for the stability of their phenotype. Nine of the 10 clones were shown to harbour one intact copy of the emm-6.1/ermC ClaI fragment integrated into the chromosome. These strains both expressed M6 protein on the surface and secreted different amounts of the molecule, since in each case the protein was produced after a transcriptional fusion of emm-6.1 with a different chromosomal promoter. A S. gordonii strain expressing large amounts of surface M6 protein, as judged by immunofluorescence and Western blot, was compared to the M- parental strain in a standard opsonophagocytosis assay. Of the isogenic pair, M6+ S. gordonii survived better in human blood and was phagocytosed at a slower rate
Expression of an allergen from the white-face hornet venom on the surface of Streptococcus gordonii
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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
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