The xylan utilization system of the plant pathogen Xanthomonas campestris pv campestris controls epiphytic life and reveals common features with oligotrophic bacteria and animal gut symbionts

Xylan is a major structural component of plant cell wall and the second most abundant plant polysaccharide in nature.Here, by combining genomic and functional analyses, we provide a comprehensive picture of xylan utilization by Xanthomonas campestris pv campestris (Xcc) and highlight its role in the adaptation of this epiphytic phytopathogen to the phyllosphere. The xylanolytic activity of Xcc depends on xylan-deconstruction enzymes but also on transporters, including two TonB-dependent outer membrane transporters (TBDTs) which belong to operons necessary for efficient growth in the presence of xylo-oligosaccharides and for optimal survival on plant leaves. Genes of this xylan utilization system are specifically induced by xylo-oligosaccharides and repressed by a LacI-family regulator named XylR. Part of the xylanolytic machinery of Xcc, including TBDT genes, displays a high degree of conservation with the xylose-regulon of the oligotrophic aquatic bacterium Caulobacter crescentus. Moreover, it shares common features, including the presence of TBDTs, with the xylan utilization systems of Bacteroides ovatus and Prevotella bryantii, two gut symbionts. These similarities and our results support an important role for TBDTs and xylan utilization systems for bacterial adaptation in the phyllosphere, oligotrophic environments and animal guts

Contrasting views on the role of mesenchymal stromal/stem cells in tumour growth : a systematic review of experimental design

The effect of mesenchymal stromal/stem cells (MSCs) on tumour growth remains controversial. Experimental evidence supports both an inhibitory and a stimulatory effect. We have assessed factors responsible for the contrasting effects of MSCs on tumour growth by doing a meta-analysis of existing literature between 2000 and May 2017. We assessed 183 original research articles comprising 338 experiments. We considered (a) in vivo and in vitro experiments, (b) whether in vivo studies were syngeneic or xenogeneic, and (c) if animals were immune competent or deficient. Furthermore, the sources and types of cancer cells and MSCs were considered together with modes of cancer induction and MSC administration. 56% of all 338 experiments reported that MSCs promote tumour growth. 78% and 79% of all experiments sourced human MSCs and cancer cells, respectively. MSCs were used in their naïve and engineered form in 86% and 14% of experiments, respectively, the latter to produce factors that could alter either their activity or that of the tumour. 53% of all experiments were conducted in vitro with 60% exposing cancer cells to MSCs via coculture. Of all in vivo experiments, 79% were xenogeneic and 63% were conducted in immune-competent animals. Tumour growth was inhibited in 80% of experiments that used umbilical cord-derived MSCs, whereas tumour growth was promoted in 64% and 57% of experiments that used bone marrow- and adipose tissue-derived MSCs, respectively. This contrasting effect of MSCs on tumour growth observed under different experimental conditions may reflect differences in experimental design. This analysis calls for careful consideration of experimental design given the large number of MSC clinical trials currently underway.The South African Medical Research Council in terms of the SAMRC’s Flagship Award Project SAMRC-RFA-UFSP-01-2013/STEM CELLS, the SAMRC Extramural Stem Cell Research and Therapy Unit, the National Research Foundation of South Africa (grant no. 86942), the National Health Laboratory Services Research Trust (grant no. 94453), the University of Pretoria Research Development Programme (A0Z778), the University of Pretoria Vice Chancellor’s Postdoctoral Fellowship and the Institute for Cellular and Molecular Medicine of the University of Pretoria.http://www.springer.comseries/5584hj2019ImmunologyOral Pathology and Oral Biolog

Training in vascular trauma surgery for non-vascular surgeons: vascular trauma surgery skills course

Background The experience of general and trauma surgeons in vascular trauma management has decreased with sub-specialization of surgery and working hours restrictions. We introduce a vascular trauma surgery skills course established to train German military surgeons prior to their deployment to conflict areas. Methods The intention and implementation of the vascular trauma course for non-vascular surgeons is described in detail. Results In hands-on courses, participants learn and train basic vascular surgical techniques on more realistic extremity, neck, and abdominal models with pulsatile vessels. A fundamental and an advanced course each provide military as well as civilian surgeons from different non-vascular specialties with a surgical skill set including direct vessel sutures, patch angioplasty, anastomosis, thrombectomy, and resuscitative endovascular balloon occlusion of the aorta (REBOA) in order to render them capable of managing major vascular injuries. Conclusion The experiences of this vascular trauma surgical skills course, initially established for military surgeons, can also be of use to all civilian general, visceral, and trauma surgeons occasionally facing traumatic or iatrogenic vascular injuries. Thus, the introduced vascular trauma course is valuable for all surgeons working in trauma centers

La compétence en question. Ecole, insertion, travail.

International audienceLa compétence : une notion polysémique et finalement quelque peu obscure. Elle est pourtant omniprésente et socialement très investie, aussi bien dans le discours commun que dans le langage des institutions chargées de la constituer et de la certifier. Quelles sont les modalités de son élaboration, dans l'école et plus largement la formation ? Comment mesurer la compétence dans l'institution scolaire mais aussi dans l'entreprise, quel sens - et même quelle utilité cette mesure peut-elle avoir ? Quel rôle la compétence joue-t-elle dans la qualification professionnelle et la carrière sociale des personnes. A partir d'objets variés mais finalement convergents, cette question de la compétence a focalisé l'attention de chercheurs réunis à Rennes (8 et 9 octobre 1992) à l'occasion des journées du Lessor

La compétence en question. Ecole, insertion, travail.

International audienceLa compétence : une notion polysémique et finalement quelque peu obscure. Elle est pourtant omniprésente et socialement très investie, aussi bien dans le discours commun que dans le langage des institutions chargées de la constituer et de la certifier. Quelles sont les modalités de son élaboration, dans l'école et plus largement la formation ? Comment mesurer la compétence dans l'institution scolaire mais aussi dans l'entreprise, quel sens - et même quelle utilité cette mesure peut-elle avoir ? Quel rôle la compétence joue-t-elle dans la qualification professionnelle et la carrière sociale des personnes. A partir d'objets variés mais finalement convergents, cette question de la compétence a focalisé l'attention de chercheurs réunis à Rennes (8 et 9 octobre 1992) à l'occasion des journées du Lessor