Reactive oxygen species and plant resistance to fungal pathogens

Reactive oxygen species (ROS) have been studied for their role in plant development as well as in plant immunity. ROS were consistently observed to accumulate in the plant after the perception of pathogens and microbes and over the years, ROS were postulated to be an integral part of the defence response of the plant. In this article we will focus on recent findings about ROS involved in the interaction of plants with pathogenic fungi. We will describe the ways to detect ROS, their modes of action and their importance in relation to resistance to fungal pathogens. In addition we include some results from works focussing on the fungal interactor and from studies investigating roots during pathogen attack

Developmental Expression of IL-2-Receptor Light Chain (CD25) in the Chicken Embryo

Thymocyte differentiation obeys the same fundamental principles in mammals as in avian species. This parallelism does not only affect the developmentally controlled acquisition of CD3, 4, 8, and TcR isotype expression, but also concerns CD25, the light chain of the interleukin-2 receptor (IL-2R). On chicken thymocytes, surface CD25, which is recognized by the monoclonal antibody INN Ch16, is first observed during day 11 of embryonic life, and peaks at day 14, when it is expressed by about one-third of all lymphoid cells. CD25 is found on subsets of all ,thymocyte populations as defined by TcRαβ, TcRγδ, 2, CD4, and CD8 expression, cortical or medullary localization, and is also present on a subset of intrathymic nurse-cell lymphocytes. These findings suggest phylogenetic conservation of the IL-2/IL-2R-triggered differentiation pathway previously described for mammalian species, thus under-lining its probable functional importance

A Systematic Review of the Perforated Duodenal Diverticula: Lessons Learned from the Last Decade

Background: The perforated duodenal diverticulum remains a rare clinical entity, the optimal management of which has not been well established. Historically, primary surgery has been the preferred treatment modality. This was called into question during the last decade, with the successful application of non-operative therapy in selected patients. The aim of this systematic review is to identify cases of perforated duodenal diverticula published over the past decade and to assess any subsequent evolution in treatment. Methods: A systematic review of English and non-English articles reporting on perforated duodenal diverticula using MEDLINE (2008-2020) was performed. Only cases of perforated duodenal diverticula in adults (> 18 years) that reported on diagnosis and treatment were included. Results: Some 328 studies were identified, of which 31 articles met the inclusion criteria. These studies included a total of 47 patients with perforated duodenal diverticula. This series suggests a trend towards conservative management with 34% (16/47) of patients managed non-operatively. In 31% (5/16) patients initially managed conservatively, a step-up approach to surgical intervention was required. Conclusion: Conservative treatment of perforated duodenal diverticula appears to be an acceptable and safe treatment strategy in stable patients without signs of peritonitis under careful observation. For patients who fail to respond to conservative treatment, a step-up approach to percutaneous drainage or surgery can be applied. If surgery is required, competence in techniques ranging from simple diverticulectomy to Roux-en-Y gastric diversion or even Whipple's procedure may be required depending on tissue friability and diverticular collar size. Keywords: Duodenal diverticulum; Duodenum; Management; Perforation

The innate immune signaling system as a regulator of disease resistance and induced systemic resistance activity against Verticillium dahliae

In the last decades, the plant innate immune responses against pathogens have been extensively studied, while biocontrol interactions between soilborne fungal pathogens and their hosts have received much less attention. Treatment of Arabidopsis thaliana with the nonpathogenic bacterium Paenibacillus alvei K165 was shown previously to protect against Verticillium dahliae by triggering induced systemic resistance (ISR). In the present study, we evaluated the involvement of the innate immune response in the K165-mediated protection of Arabidopsis against V. dahliae. Tests with Arabidopsis mutants impaired in several regulators of the early steps of the innate immune responses, including fls2, efr-1, bak1-4, mpk3, mpk6, wrky22, and wrky29 showed that FLS2 and WRKY22 have a central role in the K165-triggered ISR, while EFR1, MPK3, and MPK6 are possible susceptibility factors for V. dahliae and bak1 shows a tolerance phenomenon. The resistance induced by strain K165 is dependent on both salicylate and jasmonate-dependent defense pathways, as evidenced by an increased transient accumulation of PR1 and PDF1.2 transcripts in the aerial parts of infected plants treated with strain K165

Créatine, hypertrophie musculaire et évolution de la force: une revue systématique : travail de Bachelor

Introduction : Dans un contexte d’expansion de la consommation de compléments alimentaires, notamment à des fins d’amélioration des performances, la créatine est particulièrement prisée par les sportifs pratiquant des efforts brefs et de haute intensité. Les allégations autour d’une supplémentation en créatine sont nombreuses et revendiquent notamment une augmentation significative de la force et de l’hypertrophie musculaire. Peu de littérature scientifique traite toutefois des réels effets de cette supplémentation de manière rigoureuse et complète. But : Le but de notre travail est de définir, sur la base des connaissances actuelles, si la prise de créatine lors d'entraînements de résistance induit une réelle augmentation significative aussi bien de la force que de l’hypertrophie musculaire. Méthode : Ce travail de Bachelor est une revue systématique réalisée sur la base de l’analyse de quatre essais cliniques randomisés et d’une étude pilote, mesurant de manière simultanée l’évolution de la force et de l’hypertrophie en lien avec la prise de créatine. Seuls les articles parus après 2004 ont été pris en compte dans notre travail, en lien avec la revue de Volek et al. (1) publiée cette année-là, afin d’apporter les connaissances les plus actuelles sur le sujet. Les articles ont été sélectionnés sur la base d’une équation de recherche lancée sur les bases de données PubMed et OVID. Ils ont ensuite été triés à partir de critères d’inclusion et d’exclusion préétablis. Résultats : La majorité des études analysées dans ce travail ont mis en évidence une augmentation significative des marqueurs de l’hypertrophie musculaire chez les groupes supplémentés en créatine en comparaison aux groupes contrôles. Concernant l’évolution de la force musculaire, l’évolution des marqueurs dans la plupart des études n’était significativement pas différente entre les groupes supplémentés en créatine et les groupes contrôles, seules deux études ont montré une augmentation significative pour les groupes supplémentés en créatine. Ces études ont également relevé l’absence de différence significative entre les résultats obtenus par les groupes supplémentés en créatine et les groupes supplémentés en Whey Protein ou encore en CHO, et ce aussi bien pour l’évolution de l’hypertrophie que de la force. Conclusion : Ce travail ne permet pas de répondre à notre question de recherche. Les résultats des études ne sont pas unanimes, ce qui rend difficile d’affirmer ou non l’impact positif de la créatine sur l’hypertrophie et la force musculaire. De plus le faible nombre d’études existantes et leur méthodologie ne permettent pas d’extrapoler ces résultats à la population générale. D’après les résultats récoltés dans ce travail, la créatine semble toutefois avoir un impact plus élevé sur l’évolution de l’hypertrophie musculaire que sur la force. Afin de pouvoir se positionner plus clairement sur notre question de recherche, un plus grand nombre d’études sur une population plus large et analysant des marqueurs fiables et représentatifs des résultats recherchés est nécessaire

Influence of the live cell DNA marker DRAQ5 on chromatin-associated processes

In the last decade, live cell fluorescence microscopy experiments have revolutionized cellular and molecular biology, enabling the localization of proteins within cellular compartments to be analysed and to determine kinetic parameters of enzymatic reactions in living nuclei to be measured. Recently, in vivo DNA labelling by DNA-stains such as DRAQ5, has provided the opportunity to measure kinetic reactions of GFP-fused proteins in targeted areas of the nucleus with different chromatin compaction levels. To verify the suitability of combining DRAQ5-staining with protein dynamic measurements, we have tested the cellular consequences of DRAQ5 DNA intercalation. We show that DRAQ5 intercalation rapidly modifies both the localization and the mobility properties of several DNA-binding proteins such as histones, DNA repair, replication and transcription factors, by stimulating a release of these proteins from their substrate. Most importantly, the effect of DRAQ5 on the mobility of essential cellular enzymes results in a potent inhibition of the corresponding cellular functions. From these observations, we suggest that great caution must be used when interpreting live cell data obtained using DRAQ5

XMM-Newton observations of Extremely Red Objects and the link with luminous, X-ray obscured Quasars

We present the results of a deep (about 80 ks) XMM-Newton survey of the largest sample of near-infrared selected Extremely Red Objects (R-K>5) available to date to K_S< 19.2. At the relatively bright X-ray fluxes (F_{2-10 keV}> 4x10^{-15} cgs) and near-infrared magnitude probed by the present observations, the fraction of AGN (i.e., X-ray detected) among the ERO population is small (~3.5%); conversely, the fraction of EROs among hard X-ray selected sources is much higher (~20%). The X-ray properties of EROs detected in our XMM-Newton observation indicate absorption in excess of 10^{22} cm^{-2} in a large fraction of them. We have also considered additional samples of X-ray detected EROs available in the literature. X-ray spectral analysis of the highest S/N sources unambiguously indicates that large columns of cold gas (even >10^{23} cm^{-2}) are the rule rather than the exception. The X-ray, optical, and near-infrared properties of those X-ray selected EROs with a spectroscopic or photometric redshift nicely match those expected for quasars 2, the high-luminosity, high-redshift obscured AGNs predicted in baseline XRB synthesis models. A close correlation is detected between X- and K-band fluxes. For the AGN EROs this is consistent, under reasonable assumptions, with the relation established locally between the host galaxies and their central black holes. This suggest that the majority of EROs are powered by massive black holes accreting, on average, at about 0.03-0.1 of the Eddington limit.Comment: 33 pages, 10 figures, to appear in A&