1,720,968 research outputs found
Overexpression of DNA polymerase zeta reduces the mitochondrial mutability caused by pathological mutations in DNA polymerase gamma in yeast.
No full textIn yeast, DNA polymerase zeta (Rev3 and Rev7) and Rev1, involved in the error-prone translesion synthesis during replication of nuclear DNA, localize also in mitochondria. We show that overexpression of Rev3 reduced the mtDNA extended mutability caused by a subclass of pathological mutations in Mip1, the yeast mitochondrial DNA polymerase orthologous to human Pol gamma. This beneficial effect was synergistic with the effect achieved by increasing the dNTPs pools. Since overexpression of Rev3 is detrimental for nuclear DNA mutability, we constructed a mutant Rev3 isoform unable to migrate into the nucleus: its overexpression reduced mtDNA mutability without increasing the nuclear one
Evaluation of adhesion properties and antibacterial activities of the infant gut commensal Bifidobacterium bifidum PRL2010
No full textSerafini, Fausta et al.Bifidobacteria are extensively exploited by the food industry as health-promoting microorganisms. However, very little is known about the molecular mechanisms responsible for these beneficial activities, or the molecular players that sustain their ability to colonize and persist within the human gut. Here, we have investigated the enteric adaptation features of the gut commensal Bifidobacterium bifidum PRL2010, originally isolated from infant feces. This strain was able to survive under gastrointestinal challenges, while it was shown to adhere to human epithelial intestinal cell monolayers (Caco 2 and HT-29), thereby inhibiting adhesion of pathogenic bacteria such as Escherichia coli and Cronobacter sakazakii. © 2013 Elsevier Ltd.This work was also financially supported by Fondazione Cariparma to MV, by FEMS Advanced Fellowship 2011 and an IRCSET Embark postdoctoral fellowship to FT. DvS is a member of The Alimentary Pharmabiotic Centre, which is a Centre for Science and Technology (CSET) funded by the Science Foundation Ireland (SFI), through the Irish Government's National Development Plan (Grant no. 02/CE/B124 and 07/CE/B1368). The grant I-LINK2010-0122, funded by CSIC, is also acknowledged.Peer Reviewe
Insights into teichoic acid biosynthesis by Bifidobacterium bifidum PRL2010
No full textBifidobacteria are colonizers of the human gut, where they are interacting with their host as well as with other members of the intestinal microbiota. Teichoic acids (TAs) have previously been shown to play an important role in modulating microbe-host interactions in the human gut. However, so far, there is a paucity of information regarding the presence of TAs in the cell envelope of bifidobacteria. In silico analyses targeting the chromosomes of all 48 (sub)species that currently represent the genus Bifidobacterium revealed the presence of genes responsible for TA biosynthesis, suggesting that bifidobacteria contain both wall TAs and lipoteichoic acids. Transcriptome analyses of the infant gut commensal Bifidobacterium bifidum PRL2010 highlighted that the transcription of the presumptive TA biosynthetic loci is modulated in response to environmental conditions reflecting those of the human gut. Furthermore, chemical characterization of TAs produced by PRL2010 indicates the presence of lipoteichoic acids
Analysis of the predicted carbohydrate transport systems encoded by Bifidobacterium bifidum PRL2010
No full textThe Bifidobacterium bifidum PRL2010 genome encodes a relatively small set of predicted carbohydrate transporters. Growth
experiments and transcriptome analyses of B. bifidum PRL2010 revealed that carbohydrate utilization in this microorganism
appears to be restricted to a relatively low number of carbohydrate
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
Insights into the molecular bases of the interaction of Bifidobacterium bifidum PRL2010 with the human host and with other human gut commensals.
No full textI bifidobatteri sono tra i microrganismi maggiormente presenti nel tratto gastro-intestinale (GIT) dei mammiferi. Sono batteri anaerobi obbligati appartenenti al phylum degli Actinobacteria, Gram-positivi ad alto contenuto di G+C nel genoma. Sono state identificate 47 taxa di bifidobatteri, 11 delle quali isolate dal GIT umano. Sono i primi colonizzatori del tratto gastro-intestinale dei neonati e predominano in quelli allattati al seno, invece dopo lo svezzamento sono in quantità minore rispetto a Bacteroides ed altri gruppi microbici. Infatti, i bifidobatteri anche se non sono numericamente dominanti nella complessa microflora intestinale degli adulti, sono considerati dei commensali importanti nel promuovere lo stato di salute dell’ospite e per questa ragione sono spesso usati come componenti salutari negli alimenti funzionali.
Recentemente sono emersi numerosi approcci molecolari per l’identificazione e la caratterizzazione di ceppi di bifidobatteri. Studi basati sulla genomica (probiogenomica) hanno permesso di comprendere i meccanismi che mediano l’interazione tra microrganismo e ospite e in che modo i bifidobatteri si adattano alla nicchia ecologica umana.
In questa tesi sono stati studiati i meccanismi molecolari responsabili dell’interazione dei bifidobatteri con l’ospite e con gli altri commensali del GIT umano, utilizzando sia test in vitro che in vivo.Members of the Bifidobacterium genus are of common inhabitants of the gastro-intestinal tract (GIT) of mammals. Bifidobacteria are high G+C Gram-positive obligate anaerobes belonging to the Actinobacteria phylum. Of the 47 bifidobacterial so far identified taxa, 11 have been isolated from human GIT. Bifidobacteria are among the first colonizers of the sterile GITs of newborns and they predominate in breast-fed infants until weaning. After this phase Bacteroides and other groups become dominant. In fact, bifidobacteria are not numerically dominant in the complex adult intestinal microflora, but they are considered as key commensals because they promote a healthy status in the host. For this reason bifidobacteria are often used as healthy components in functional foods. Recently numerous molecular approaches have emerged for the identification and characterization of bifidobacterial strains. In this context, genomic-based efforts, i.e., probiogenomics, have helped us to understand the mechanism mediating the host-microbiota interaction and in which way the bifidobacteria adapt themselves to the gastro-intestinal tract of the host.
In this thesis were investigated the molecular bases sustaining the interaction of bifidobacteria with the host as well as with the other commensals members of the human GIT through in vitro and in vivo tests
Insights into the molecular bases of the interaction of Bifidobacterium bifidum PRL2010 with the human host and with other human gut commensals.
No full textI bifidobatteri sono tra i microrganismi maggiormente presenti nel tratto gastro-intestinale (GIT) dei mammiferi. Sono batteri anaerobi obbligati appartenenti al phylum degli Actinobacteria, Gram-positivi ad alto contenuto di G+C nel genoma. Sono state identificate 47 taxa di bifidobatteri, 11 delle quali isolate dal GIT umano. Sono i primi colonizzatori del tratto gastro-intestinale dei neonati e predominano in quelli allattati al seno, invece dopo lo svezzamento sono in quantità minore rispetto a Bacteroides ed altri gruppi microbici. Infatti, i bifidobatteri anche se non sono numericamente dominanti nella complessa microflora intestinale degli adulti, sono considerati dei commensali importanti nel promuovere lo stato di salute dell’ospite e per questa ragione sono spesso usati come componenti salutari negli alimenti funzionali.
Recentemente sono emersi numerosi approcci molecolari per l’identificazione e la caratterizzazione di ceppi di bifidobatteri. Studi basati sulla genomica (probiogenomica) hanno permesso di comprendere i meccanismi che mediano l’interazione tra microrganismo e ospite e in che modo i bifidobatteri si adattano alla nicchia ecologica umana.
In questa tesi sono stati studiati i meccanismi molecolari responsabili dell’interazione dei bifidobatteri con l’ospite e con gli altri commensali del GIT umano, utilizzando sia test in vitro che in vivo.Members of the Bifidobacterium genus are of common inhabitants of the gastro-intestinal tract (GIT) of mammals. Bifidobacteria are high G+C Gram-positive obligate anaerobes belonging to the Actinobacteria phylum. Of the 47 bifidobacterial so far identified taxa, 11 have been isolated from human GIT. Bifidobacteria are among the first colonizers of the sterile GITs of newborns and they predominate in breast-fed infants until weaning. After this phase Bacteroides and other groups become dominant. In fact, bifidobacteria are not numerically dominant in the complex adult intestinal microflora, but they are considered as key commensals because they promote a healthy status in the host. For this reason bifidobacteria are often used as healthy components in functional foods. Recently numerous molecular approaches have emerged for the identification and characterization of bifidobacterial strains. In this context, genomic-based efforts, i.e., probiogenomics, have helped us to understand the mechanism mediating the host-microbiota interaction and in which way the bifidobacteria adapt themselves to the gastro-intestinal tract of the host.
In this thesis were investigated the molecular bases sustaining the interaction of bifidobacteria with the host as well as with the other commensals members of the human GIT through in vitro and in vivo tests
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