Comparative Genomics of Pathogenic and Nonpathogenic Strains of Xanthomonas arboricola Unveil Molecular and Evolutionary Events Linked to Pathoadaptation

The bacterial species Xanthomonas arboricola contains plant pathogenic and nonpathogenic strains. It includes the pathogen X. arboricola pv. juglandis, causing the bacterial blight of Juglans regia. The emergence of a new bacterial disease of J, regia in France called vertical oozing canker (VOC) was previously described and the causal agent was identified as a distinct genetic lineage within the pathovar Symptoms on walnut leaves and fruits are similar to those of a bacterial blight but VOC includes also cankers on trunk and branches. In this work, we used comparative genomics and physiological tests to detect differences between four X. arboricola strains isolated from walnut tree: strain CFBP 2528 causing walnut blight (WB), strain CFBP 7179 causing VOC and two nonpathogenic strains, CFBP 7634 and CFBP 7651, isolated from healthy walnut buds. Whole genome sequence comparisons revealed that pathogenic strains possess a larger and wider range of mobile genetic elements than nonpathogenic strains. One pathogenic strain, CFBP 7179, possessed a specific integrative and conjugative element (ICE) of 95 kb encoding genes involved in copper resistance, transport and regulation. The type three effector repertoire was larger in pathogenic strains than in nonpathogenic strains. Moreover, CFBP 7634 strain lacked the type three secretion system encoding genes. The flagellar system appeared incomplete and nonfunctional in the pathogenic strain CFBP 2528. Differential sets of chemoreceptor and different repertoires of genes coding adhesins were identified between pathogenic and nonpathogenic strains. Besides these differences, some strain-specific differences were also observed. Altogether, this study provides valuable insights to highlight the mechanisms involved in ecology, environment perception, plant adhesion and interaction, leading to the emergence of new strains in a dynamic environment

Development of multilocus variable-number tandem repeat analysis (MLVA) for Xanthomonas arboricola pathovars

Xanthomonas arboricola is an important bacterial species, the pathovars of which are responsible for bacterial blight diseases on stone fruit, hazelnut, Persian walnut, poplar, strawberry, poinsettia and banana. In this study, we evaluated variable number tandem repeats (VNTR) as a molecular typing tool for assessing the genetic diversity within pathovars of X. arboricola. Screening of the X. arboricola pv. pruni genome sequence (CFBP5530 strain) predicted 51 candidate VNTR loci. Primer pairs for polymerase chain reaction (PCR) amplification of all 51 loci were designed, and their discriminatory power was initially evaluated with a core collection of 8 X. arboricola strains representative of the different pathovars. Next, the 26 polymorphic VNTR loci present in all strains were used for genotyping a collection of 61 strains. MLVA is a typing method that clearly differentiates X. arboricola strains. The MLVA scheme described in this study is a rapid and reliable molecular typing tool that can be used for further epidemiological studies of bacterial diseases caused by X. arboricola pathovars

Morfología de los otolitos sagitta, lapillus y asteriscus de Genidens barbus de distribución patagónica

Otoliths are calcium carbonate structures, deposited as aragonite, located in the inner ear of bony fish. In recent years, they have become a useful tool for the determination of fish species, trophic content, age studies, and the identification of fish stocks. The objective of this work was to describe the morphology of the three pairs of otoliths of the marine catfish Genidens barbus of Patagonian distribution. Otoliths of specimens obtained at four sampling points in the Negro River were analyzed. It was observed that otoliths presented the general morphological pattern proposed for Siluriformes, where lapilli are the largest and most robust of the three. Lapillus presented a rounded shape, a pronounced elevation in the central position, a delimited sulcus, but not very evident, without evidence of a minor sulcus. The sagitta is claviform, with an elongated conical posterior region, dorsal wings that continue as lateral expansions called basal wings, and the presence of a fissure. The asteriscus has an ear shape, a median opening, a short pointed rostrum, a poorly developed anti-rostrum and a slightly curved acoustic fossa. In this work, sagitta and asteriscus otoliths were described for the first time for the species G. barbus, thus completing the description of the three pairs.Los otolitos son estructuras de carbonato de calcio, depositado en forma de aragonita, ubicados en el oído interno de peces óseos. En los últimos años se han convertido en una herramienta útil para la determinación de especies ícticas, estudios de edad, contenidos tróficos, identificación de stocks pesqueros. El objetivo del presente trabajo fue describir la morfología de los tres pares de otolitos del bagre marino Genidens barbus de distribución patagónica. Se analizaron los otolitos de ejemplares obtenidos en cuatro puntos de muestreo en el Río Negro. Se observó que los otolitos presentan el patrón morfológico general propuesto para Siluriformes, donde los lapilli son los más grandes y robustos de los tres. El lapillus presentó forma redondeada, elevación pronunciada en posición central, sulcus delimitado, pero poco evidente, sin evidencia de sulcus menor. La sagitta es claviforme, con región posterior cónica alargada, alas dorsales que se continúan como expansiones laterales denominadas alas basales y presencia de fisura. El asteriscus tiene forma auricular, abertura mediana, rostro corto aguzado, antirrostro poco desarrollado y fosa acústica poco curva. En este trabajo se describen por primera vez los otolitos sagitta y asteriscus para la especie G. barbus, completando así la descripción de los tres pares

Regrets Associated with Providing Healthcare: Qualitative Study of Experiences of Hospital-Based Physicians and Nurses

Regret is an unavoidable corollary of clinical practice. Physicians and nurses perform countless clinical decisions and actions, in a context characterised by time pressure, information overload, complexity and uncertainty

Slower is not always better: Response-time evidence clarifies the limited role of miserly information processing in the Cognitive Reflection Test

We report a study examining the role of `cognitive miserliness' as a determinant of poor performance on the standard three-item Cognitive Reflection Test (CRT). The cognitive miserliness hypothesis proposes that people often respond incorrectly on CRT items because of an unwillingness to go beyond default, heuristic processing and invest time and effort in analytic, reflective processing. Our analysis (N = 391) focused on people's response times to CRT items to determine whether predicted associations are evident between miserly thinking and the generation of incorrect, intuitive answers. Evidence indicated only a weak correlation between CRT response times and accuracy. Item-level analyses also failed to demonstrate predicted response time differences between correct analytic and incorrect intuitive answers for two of the three CRT items. We question whether participants who give incorrect intuitive answers on the CRT can legitimately be termed cognitive misers and whether the three CRT items measure the same general construct

Short-term reward experience biases inference despite dissociable neural correlates

Contains fulltext : 179643.pdf (publisher's version ) (Open Access)Optimal decision-making employs short-term rewards and abstract long-term information based on which of these is deemed relevant. Employing short- vs. long-term information is associated with different learning mechanisms, yet neural evidence showing that these two are dissociable is lacking. Here we demonstrate that long-term, inference-based beliefs are biased by short-term reward experiences and that dissociable brain regions facilitate both types of learning. Long-term inferences are associated with dorsal striatal and frontopolar cortex activity, while short-term rewards engage the ventral striatum. Stronger concurrent representation of reward signals by mediodorsal striatum and frontopolar cortex correlates with less biased, more optimal individual long-term inference. Moreover, dynamic modulation of activity in a cortical cognitive control network and the medial striatum is associated with trial-by-trial control of biases in belief updating. This suggests that counteracting the processing of optimally to-be-ignored short-term rewards and cortical suppression of associated reward-signals, determines long-term learning success and failure.14 p