The toxbox: specific DNA sequence requirements for activation of Vibrio cholerae virulence genes by ToxT

The Gram-negative, curved rod Vibrio cholerae causes the severe diarrhoeal disease cholera. The two major virulence factors produced by V. cholerae during infection are the cholera toxin (CT) and the toxin-coregulated pilus (TCP). Transcription of the genes encoding both CT and the components of the TCP is directly activated by ToxT, a transcription factor in the AraC/XylS family. ToxT binds upstream of the ctxAB genes, encoding CT, and upstream of tcpA , the first gene in a large operon encoding the components of the TCP. The DNA sequences upstream of ctxAB and tcpA that contain ToxT binding sites do not have any significant similarity other than being AT-rich. Extensive site-directed mutagenesis was performed on the region upstream of tcpA previously shown to be protected by ToxT, and we identified specific base pairs important for activation of tcpA transcription by ToxT. This genetic approach was complemented by copper-phenanthroline footprinting experiments that showed protection by ToxT of the base pairs identified as most important for transcription activation in the mutagenesis experiments. Based on this new information and on previous work, we propose the presence of a ToxT-binding motif – the ‘toxbox’– in promoters regulated by ToxT. At tcpA , two toxbox elements are present in a direct repeat configuration and both are required for activation of transcription by ToxT. The identity of only a few of the base pairs within the toxbox is important for activation by ToxT, and we term these the core toxbox elements. Lastly, we examined ToxT binding to a mutant having 5 bp inserted between the two toxboxes at tcpA and found that occupancy of both binding sites is retained regardless of the positions of the binding sites relative to each other on the face of the DNA. This suggests that ToxT binds independently as a monomer to each toxbox in the tcpA direct repeat, in accordance with what we observed previously with the inverted repeat ToxT sites between acfA and acfD .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75755/1/j.1365-2958.2006.05053.x.pd

Seguimiento de las guías españolas para el manejo del asma por el médico de atención primaria: un estudio observacional ambispectivo

Objetivo Evaluar el grado de seguimiento de las recomendaciones de las versiones de la Guía española para el manejo del asma (GEMA 2009 y 2015) y su repercusión en el control de la enfermedad. Material y métodos Estudio observacional y ambispectivo realizado entre septiembre del 2015 y abril del 2016, en el que participaron 314 médicos de atención primaria y 2.864 pacientes. Resultados Utilizando datos retrospectivos, 81 de los 314 médicos (25, 8% [IC del 95%, 21, 3 a 30, 9]) comunicaron seguir las recomendaciones de la GEMA 2009. Al inicio del estudio, 88 de los 314 médicos (28, 0% [IC del 95%, 23, 4 a 33, 2]) seguían las recomendaciones de la GEMA 2015. El tener un asma mal controlada (OR 0, 19, IC del 95%, 0, 13 a 0, 28) y presentar un asma persistente grave al inicio del estudio (OR 0, 20, IC del 95%, 0, 12 a 0, 34) se asociaron negativamente con tener un asma bien controlada al final del seguimiento. Por el contrario, el seguimiento de las recomendaciones de la GEMA 2015 se asoció de manera positiva con una mayor posibilidad de que el paciente tuviera un asma bien controlada al final del periodo de seguimiento (OR 1, 70, IC del 95%, 1, 40 a 2, 06). Conclusiones El escaso seguimiento de las guías clínicas para el manejo del asma constituye un problema común entre los médicos de atención primaria. Un seguimiento de estas guías se asocia con un control mejor del asma. Existe la necesidad de actuaciones que puedan mejorar el seguimiento por parte de los médicos de atención primaria de las guías para el manejo del asma. Objective: To assess the degree of compliance with the recommendations of the 2009 and 2015 versions of the Spanish guidelines for managing asthma (Guía Española para el Manejo del Asma [GEMA]) and the effect of this compliance on controlling the disease. Material and methods: We conducted an observational ambispective study between September 2015 and April 2016 in which 314 primary care physicians and 2864 patients participated. Results: Using retrospective data, we found that 81 of the 314 physicians (25.8%; 95% CI 21.3–30.9) stated that they complied with the GEMA2009 recommendations. At the start of the study, 88 of the 314 physicians (28.0%; 95% CI 23.4–33.2) complied with the GEMA2015 recommendations. Poorly controlled asthma (OR, 0.19; 95% CI 0.13–0.28) and persistent severe asthma at the start of the study (OR, 0.20; 95% CI 0.12–0.34) were negatively associated with having well-controlled asthma by the end of the follow-up. In contrast, compliance with the GEMA2015 recommendations was positively associated with a greater likelihood that the patient would have well-controlled asthma by the end of the follow-up (OR, 1.70; 95% CI 1.40–2.06). Conclusions: Low compliance with the clinical guidelines for managing asthma is a common problem among primary care physicians. Compliance with these guidelines is associated with better asthma control. Actions need to be taken to improve primary care physician compliance with the asthma management guidelines

Estimation of the parameters of a normal population under ambiguity

SIGLEAvailable from TIB Hannover: RA 7759(305) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Identification of circulating lncRNAs associated with gallbladder cancer risk by tissue-based preselection, cis-eQTL validation, and analysis of association with genotype-based expression.

Long noncoding RNAs (lncRNAs) play key roles in cell processes and are good candi-dates for cancer risk prediction. Few studies have investigated the association between individual genotypes and lncRNA expression. Here we integrate three separate datasets with information on lncRNA expression only, both lncRNA expression and genotype, and genotype information only to identify circulating lncRNAs associated with the risk of gallbladder cancer (GBC) using robust linear and logistic regression techniques. In the first dataset, we preselect lncRNAs based on expression changes along the sequence “gallstones → dysplasia → GBC”. In the second dataset, we validate associations between genetic variants and serum expression levels of the preselected lncR-NAs (cis-lncRNA-eQTLs) and build lncRNA expression prediction models. In the third dataset, we predict serum lncRNA expression based on individual genotypes and assess the association between genotype-based expression and GBC risk. AC084082.3 and LINC00662 showed increasing expression levels (p-value = 0.009), while C22orf34 expression decreased in the sequence from gallstones to GBC (p-value = 0.04). We identified and validated two cis-LINC00662-eQTLs (r2 = 0.26) and three cis-C22orf34-eQTLs (r2 = 0.24). Only LINC00662 showed a genotyped-based serum expression associated with GBC risk (OR = 1.25 per log2 expression unit, 95% CI 1.04–1.52, p-value = 0.02). Our results suggest that preselection of lncRNAs based on tissue samples and exploitation of cis-lncRNA-eQTLs may facilitate the identification of circulating noncoding RNAs linked to cancer risk