BackgroundWhole genome transcriptomic analysis is a powerful approach to elucidate the molecular mechanisms controlling the pathogenesis of obligate intracellular bacteria. However, the major hurdle ...resides in the low quantity of prokaryotic mRNAs extracted from host cells. Our model Ehrlichia ruminantium (ER), the causative agent of heartwater, is transmitted by tick Amblyomma variegatum. This bacterium affects wild and domestic ruminants and is present in Sub-Saharan Africa and the Caribbean islands. Because of its strictly intracellular location, which constitutes a limitation for its extensive study, the molecular mechanisms involved in its pathogenicity are still poorly understood.ResultsWe successfully adapted the SCOTS method (Selective Capture of Transcribed Sequences) on the model Rickettsiales ER to capture mRNAs. Southern Blots and RT-PCR revealed an enrichment of ER's cDNAs and a diminution of ribosomal contaminants after three rounds of capture. qRT-PCR and whole-genome ER microarrays hybridizations demonstrated that SCOTS method introduced only a limited bias on gene expression. Indeed, we confirmed the differential gene expression between poorly and highly expressed genes before and after SCOTS captures. The comparative gene expression obtained from ER microarrays data, on samples before and after SCOTS at 96 hpi was significantly correlated (R2 = 0.7). Moreover, SCOTS method is crucial for microarrays analysis of ER, especially for early time points post-infection. There was low detection of transcripts for untreated samples whereas 24% and 70.7% were revealed for SCOTS samples at 24 and 96 hpi respectively.ConclusionsWe conclude that this SCOTS method has a key importance for the transcriptomic analysis of ER and can be potentially used for other Rickettsiales. This study constitutes the first step for further gene expression analyses that will lead to a better understanding of both ER pathogenicity and the adaptation of obligate intracellular bacteria to their environment.
Introduction
This pilot study aims to further document mindfulness‐based stress reduction (MBSR)'s effect on well‐being while exploring its impact on errors among hospital nurses.
Background
The ...concept of mindfulness has been found to be highly relevant to holistic nursing practices but remains understudied and underused. Preliminary evidence suggests that MBSR can reduce stress among nurses. As stress and mental processes such as inattention are potential sources of error, MBSR may also help to improve patient safety. Reducing errors is of significant relevance in healthcare settings.
Design
A randomized controlled trial with a matched pair design was conducted.
Methods
Seventy Registered Nurses and licensed practical nurses were randomized to MBSR (N = 37) or a waitlist control condition (N = 33).
Results
Intention‐to‐treat ANCOVAs revealed that MBSR produced significant improvements in distress. High levels of treatment satisfaction were reported by a majority of participants. Of the nurses who reported that errors had been a problem for them (28.6%), a perceived improvement was noticed by over a third (37.5%) at 3 months post‐treatment.
Conclusion
These initial findings suggest that the benefits of MBSR may extend to nursing errors.
摘要
简介
该初步研究旨在进一步记录正念减压(MBSR)对医院护士幸福感的影响,同时探讨其对医院护士出现错误的影响。
背景
已经发现正念概念与整体护理实践高度相关,但仍未得到充分研究,也未充分利用。初步证据表明,正念减压可以减轻护士的压力。由于压力和心理过程(如注意力不集中)是潜在的错误来源,正念减压也可能有助于提高患者安全性。减少错误对于医疗保健来说具有重要意义。
设计
进行的随机对照试验采用了配对设计。
方法
将70名经注册的护士和执业护士随机分配到正念减压组(N = 37)或候补对照组(N = 33)。
结果
意向治疗协方差分析结果显示正念减压在遭遇困境时有显著的改善效果。大多数参与者表示对疗效的满意度较高。在正念减压治疗后的第三个月,对于表示犯错误对他们来说是个问题的护士(28.6%)中,超过三分之一(37.5%)的护士感觉到有所改善。
结论
这些初步研究结果表明,正念减压的益处可能有助于降低护理错误率。
The North-east American Rainbow smelt (Osmerus mordax) is composed of two glacial races first identified through the spatial distribution of two distinct mtDNA lineages. Contemporary breeding ...populations of smelt in the St. Lawrence estuary comprise contrasting mixtures of both lineages, suggesting that the two races came into secondary contact in this estuary. The overall objective of this study was to assess the role of intraspecific genetic admixture in the morphological diversification of the estuarine rainbow smelt population complex. The morphology of mixed-ancestry populations varied as a function of the relative contribution of the two races to estuarine populations, supporting the hypothesis of genetic admixture. Populations comprising both ancestral mtDNA races did not exhibit intermediate morphologies relative to pure populations but rather exhibited many traits that exceeded the parental trait values, consistent with the hypothesis of transgressive segregation. Evidence for genetic admixture at the level of the nuclear gene pool, however, provided only partial support for this hypothesis. Variation at nuclear AFLP markers revealed clear evidence of the two corresponding mtDNA glacial races. The admixture of the two races at the nuclear level is only pronounced in mixed-ancestry populations dominated by one of the mtDNA lineages, the same populations showing the greatest degree of morphological diversification and population structure. In contrast, mixed-ancestry populations dominated by the alternate mtDNA lineage showed little evidence of introgression of the nuclear genome, little morphological diversification and little contemporary population genetic structure. These results only partially support the hypothesis of transgressive segregation and may be the result of the differential effects of natural selection acting on admixed genomes from different sources.
Vicariant geographic isolation and resource partitioning have long been independently identified as processes contributing to the morphological divergence of closely-related species. However, little ...is known about the extent to which vicariant history influences the adaptive ecological divergence associated with resource partitioning and trophic specialization within species. The present study thus quantified the contribution of vicariant historical genetic divergence to the adaptive contemporary morphological divergence of intraspecific feeding specialists in the Rainbow smelt (Pisces: Osmerus mordax). This species is characterized by the polyphyletic origin of two lacustrine feeding specialists originating in two intraspecific lineages associated with independent glacial refuges. The historical genetic segregation was initiated approximately 350 000 years ago, whereas the lacustrine trophic segregation arose within the past 10 000 years. Wild caught lacustrine smelt populations were grouped a priori based on known historical genetic identities (Acadian and Atlantic mitochondrial DNA clades) and contemporary feeding specializations (microphageous and macrophageous morphotypes). The present study demonstrated that independent suites of correlated morphological traits are associated with either vicariant history or contemporary feeding specializations. Second, functionally-similar feeding specialists exhibit distinct morphologies resulting largely from vicariant historical processes. Although, the evolutionary processes producing historical phenotypes remains unknown, the results obtained demonstrate how adaptive radiation associated with ecological resource partitioning and feeding specializations can be strongly influenced by intraspecific phenotypic diversification resulting from relatively recent vicariant histories.
The North-east American Rainbow smelt (Osmerus mordax) is composed of two glacial races first identified through the spatial distribution of two distinct mtDNA lineages. Contemporary breeding ...populations of smelt in the St. Lawrence estuary comprise contrasting mixtures of both lineages, suggesting that the two races came into secondary contact in this estuary. The overall objective of this study was to assess the role of intraspecific genetic admixture in the morphological diversification of the estuarine rainbow smelt population complex. The morphology of mixed-ancestry populations varied as a function of the relative contribution of the two races to estuarine populations, supporting the hypothesis of genetic admixture. Populations comprising both ancestral mtDNA races did not exhibit intermediate morphologies relative to pure populations but rather exhibited many traits that exceeded the parental trait values, consistent with the hypothesis of transgressive segregation. Evidence for genetic admixture at the level of the nuclear gene pool, however, provided only partial support for this hypothesis. Variation at nuclear AFLP markers revealed clear evidence of the two corresponding mtDNA glacial races. The admixture of the two races at the nuclear level is only pronounced in mixed-ancestry populations dominated by one of the mtDNA lineages, the same populations showing the greatest degree of morphological diversification and population structure. In contrast, mixed-ancestry populations dominated by the alternate mtDNA lineage showed little evidence of introgression of the nuclear genome, little morphological diversification and little contemporary population genetic structure. These results only partially support the hypothesis of transgressive segregation and may be the result of the differential effects of natural selection acting on admixed genomes from different sources.
Some Escherichia coli strains isolated from intestinal or extraintestinal infections in pigs produce cytotoxic necrotizing factor 1 (CNF1). In order to analyze the role of CNF1 in the pathogenesis of ...porcine colibacillosis, newborn colostrum-deprived germfree piglets were orally inoculated with a wild-type CNF1-producing strain (M623) or with an isogenic cnf1 mutant (M623ΔCNF1). The two isogenic strains induced a high mortality with similar lung and serosal inflammatory lesions, indicating that both strains were pathogenic in these piglets. Bacterial counts in various organs of inoculated piglets revealed an intestinal predisposition of M623 and M623ΔCNF1 strains for the cecum and colon. Extraintestinal organs (lungs, liver, spleen, and kidney) were also colonized by both strains. Similar colonization of intestinal and extraintestinal tissues in animals inoculated with either strain was observed, except in the ileum, where M623 showed a higher colonization than M623ΔCNF1. Intestinal (ileum and colon), extraintestinal (lung and kidney), and immune (mesenteric lymph nodes and spleen) tissues were sampled at 1 day postinoculation and analyzed for cytokine expression by a reverse transcriptase PCR technique. Inoculation with E. coli M623 induced an enhanced expression of inflammatory cytokines (interleukin-1α IL-1α, tumor necrosis factor α, and IL-12p40) in the intestinal organs compared to uninoculated piglets or piglets inoculated with nonpathogenic intestinal E. coli 862B, which is also able to colonize the intestinal tract. There was little difference in cytokine transcript levels in the intestinal and extraintestinal organs in piglets inoculated with E. colistrains M623 or M623ΔCNF1, except in the ileum, where IL-1α and IL-8 mRNA levels correlated with bacterial colonization. Expression of regulatory cytokines (gamma interferon and IL-4) was weak in immune tissues from piglets inoculated with M623 or M623ΔCNF1. Taken together, our data indicate that the CNF1-producing strain, M623, is pathogenic and induces inflammatory cytokine expression in germfree, colostrum-deprived piglets. Nevertheless, in this model, the CNF1 toxin does not appear to be a major factor for pathogenicity or cytokine response, as demonstrated by the use of an isogenic cnf1mutant.
Ce numéro de Lidil, largement consacré à l’acquisition et à l’enseignement de la morphographie du français, porte d’une part sur l’enfant et son rythme d’appropriation du système linguistique et ...d’autre part sur les processus à l’œuvre dans une perspective didactique.
PDF
