Most bacteria alternate between a free living planktonic lifestyle and the formation of structured surface-associated communities named biofilms. The transition between these two lifestyles requires ...a precise and timely regulation of the factors involved in each of the stages that has been likened to a developmental process. Here we characterize the involvement of the transcriptional regulator FleQ and the second messenger cyclic diguanylate in the coordinate regulation of multiple functions related to motility and surface colonization in Pseudomonas putida. Disruption of fleQ caused strong defects in flagellar motility, biofilm formation and surface attachment, and the ability of this mutation to suppress multiple biofilm-related phenotypes associated to cyclic diguanylate overproduction suggests that FleQ mediates cyclic diguanylate signaling critical to biofilm growth. We have constructed a library containing 94 promoters potentially involved in motility and biofilm development fused to gfp and lacZ, screened this library for FleQ and cyclic diguanylate regulation, and assessed the involvement of alternative σ factors σN and FliA in the transcription of FleQ-regulated promoters. Our results suggest a dual mode of action for FleQ. Low cyclic diguanylate levels favor FleQ interaction with σN-dependent promoters to activate the flagellar cascade, encompassing the flagellar cluster and additional genes involved in cyclic diguanylate metabolism, signal transduction and gene regulation. On the other hand, characterization of the FleQ-regulated σN- and FliA-independent PlapA and PbcsD promoters revealed two disparate regulatory mechanisms leading to a similar outcome: the synthesis of biofilm matrix components in response to increased cyclic diguanylate levels.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The Pseudomonas putida flhA-flhF-fleN-fliA cluster encodes a component of the flagellar export gate and three regulatory elements potentially involved in flagellar biogenesis and other functions. ...Here we show that these four genes form an operon, whose transcription is driven from the upstream PflhA promoter. A second promoter, PflhF, provides additional transcription of the three distal genes. PflhA and PflhF are σN-dependent, activated by the flagellar regulator FleQ, and negatively regulated by FleN. Motility, surface adhesion and colonization defects of a transposon insertion mutant in flhF revealed transcriptional polarity on fleN and fliA, as the former was required for strong surface adhesion and biofilm formation, and the latter was required for flagellar synthesis. On the other hand, FlhF and FleN were necessary to attain proper flagellar location and number for a fully functional flagellar complement. FleN, along with FleQ and the second messenger c-di-GMP differentially regulated transcription of lapA and the bcs operon, encoding a large adhesion protein and cellulose synthase. FleQ positively regulated the PlapA promoter and activation was antagonized by FleN and c-di-GMP. PbcsD was negatively regulated by FleQ and FleN, and repression was antagonized by c-di-GMP. FleN promoted FleQ binding to both PlapA and PbcsD in vitro, while c-di-GMP antagonized interaction with PbcsD and stimulated interaction with PlapA. A single FleQ binding site in PlapA was critical to activation in vivo. Our results suggest that FleQ, FleN and c-di-GMP cooperate to coordinate the regulation of flagellar motility and biofilm development.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Las cenefas y orlas caladas constituyen un elemento característico de la pintura del IV estilo pompeyano y de la producción local en las provincias a partir de la segunda mitad del siglo I d.C., y ...hasta el siglo II d.C. aproximadamente, siendo un elemento clave para la datación e identificación de talleres itálicos y locales. El presente trabajo constituye una compendio y análisis de todas las documentadas en contextos hispanos con el objetivo de catalogarlas y establecer una clasificación en base a su tipología y cronología a partir de los datos contextuales obtenidos de cada uno de los yacimientos a los que corresponden. Pretendemos que este trabajo sirva de referencia para la futura identificación y datación de cenefas y orlas caladas, así como de los conjuntos que decoran.
In this paper we describe the archaeological and archaeometric analysis of a Third Pompeian Style assemblage from the Blanes dump in Mérida (Spain). Based on the pottery context, the material would ...have been part of the decoration of a public or private space remodelled towards the end of the 1st century AD. Several samples from to the middle area of the assemblage, including panels, inter-panels and a frieze, were selected and studied using X-ray diffraction (XRD), X-ray fluorescence (XRF), Raman, gas chromatography and petrographic analysis. The results revealed the use of hematite, cinnabar, minium and goethite in different panels, as well as goethite, Egyptian blue, calcite, glauconite and carbon for the decorative motifs. They allowed us to define the painting techniques used and how they have affected the degradation of the pigments.
Las excavaciones en la villa romana de Portmán (Cartagena-La Unión, Murcia), han permitido recuperar un gran número de vestigios materiales y nuevos espacios tanto domésticos como de producción y ...almacenamiento con los que conocer mejor la complejidad y diversidad de usos de la misma. Estas intervenciones sitúan a la villa como una de las más importantes de la región tanto por su cronología, morfología y estructuras, como por su programa ornamental. No obstante, las particularidades administrativas del yacimiento, de propiedad estatal, pero de competencias transferidas a la Comunidad Autónoma y en un término municipal que no se corresponde con el sitio físico/geográfico, han dificultado una actuación ordenada y planificada en el tiempo, que solo desde 2015 ha sido posible con los trabajos realizados desde la Universidad de Murcia. El objetivo de este trabajo es plantear una estrategia de puesta en valor atendiendo a sus características y necesidades, partiendo de la base de las estrategias museográficas y de conservación y difusión actuales que se vienen aplicando también en otros parques arqueológicos y museos de la región.
Biofilm dispersal is a genetically programmed response enabling bacterial cells to exit the biofilm in response to particular physiological or environmental conditions. In Pseudomonas putida ...biofilms, nutrient starvation triggers c-di-GMP hydrolysis by phosphodiesterase BifA, releasing inhibition of protease LapG by the c-di-GMP effector protein LapD, and resulting in proteolysis of the adhesin LapA and the subsequent release of biofilm cells. Here we demonstrate that the stringent response, a ubiquitous bacterial stress response, is accountable for relaying the nutrient stress signal to the biofilm dispersal machinery. Mutants lacking elements of the stringent response - (p)ppGpp sythetases RelA and SpoT and/or DksA - were defective in biofilm dispersal. Ectopic (p)ppGpp synthesis restored biofilm dispersal in a ∆relA ∆spoT mutant. In vivo gene expression analysis showed that (p)ppGpp positively regulates transcription of bifA, and negatively regulates transcription of lapA and the lapBC, and lapE operons, encoding a LapA-specific secretion system. Further in vivo and in vitro characterization revealed that the PbifA promoter is dependent on the flagellar σ factor FliA, and positively regulated by ppGpp and DksA. Our results indicate that the stringent response stimulates biofilm dispersal under nutrient limitation by coordinately promoting LapA proteolysis and preventing de novo LapA synthesis and secretion.
The emergence of triptans represented a breakthrough in the treatment of migraine, but in clinical practice, patients describe symptoms that resemble those of a hangover after taking them. We propose ...the use of the Hangover Symptoms Scale (HSS) to evaluate this syndrome in patients that take triptans, which may help identify patients at higher risk of presenting these adverse effects that may interfere with therapeutic compliance.A cross-sectional observational pilot study with prospective data collection through a clinical-demographic questionnaire and the HSS was carried out on patients with migraine treated in headache units in 3 tertiary hospitals in Madrid.Sixty-six patients were included in the study. The median HSS was 4 and all symptoms were present in at least 15% of the patients, with difficulty to concentrate being the most frequent (57.6%). No significant differences were found between the presence of a higher HSS score and the sociodemographic characteristics of the patient or his migraine. The presence of aura was associated with a higher percentage of trembling (P = 0.029) and fatigue (nonvisual, polymodal auras; P = 0.017).According to our study, triptans are responsible for a set of symptoms overlapping with those that occur during a hangover. Therefore, we propose that the HSS could be a useful tool for the evaluation and quantification of these effects in patients receiving triptans. In addition, we found that clinical features could be more frequently associated with the appearance of these adverse effects that, however, are not related to any particular patient profile.
El presente estudio pretende abordar el análisis de un conjunto de fragmentos de terra sigillata itálica provenientes de diferentes campañas de excavación realizadas en los años 1977-1978, 1995 y ...2004 en el Cerro del Molinete de Cartagena y en 2006-2007 en la Villa Romana de Portmán, a fin de determinar las formas y producciones de este tipo presentes en el territorium de Carthago Nova y conocer la articulación del comercio de estas producciones entre la ciudad y el campo.
The digestive manifestations of a SARS-CoV-2 infection are varied and nonspecific. The appearance of portal thrombosis in these patients is very rare. Facing a patient with a diagnosis of acute ...portal thrombosis, we must rule out that the trigger is an intra-abdominal infectious process. We present the case of a patient diagnosed with severe pneumonia due to SARS-CoV-2 infection with elevated D-Dimer and a concomitant diagnosis of portal thrombosis not attributed to other causes.
During the excavations carried out since 2017 in the House of the Mithraeum (Casa del Mitreo) in Mérida a collection of paintings was recovered from Room 11, which had been abandoned in the late 3rd ...c. CE after a fire. The remains included fragments of molded stucco cornices, with braided esparto grass ropes on the reverse that were used to attach them to the ceiling. This article presents the descriptive and technical study of the finds and their compositional analysis using scanning electron microscopy and X-ray diffraction. Data resulting from these analyses allow us to understand the fragments’ composition and technical execution, and even the possible circulation of workshops and raw materials.
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