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International audience; Partition systems are widespread among bacterial chromosomes. They are composed of two effectors, ParA and ParB, and cis acting sites, parS, located close to the replication origin of the chromosome (oriC). ParABS participate in chromosome segregation, at least in part because they serve to properly position sister copies of oriC. A fourth element, located at cell poles, is also involved in some cases, such as HubP for the ParABS1 system of Vibrio cholerae chromosome 1 (ch1). The polar anchoring of oriC of ch1 (oriC1) is lost when HubP or ParABS1 are inactivated. Here, we report that in the absence of HubP, ParABS1 actively maintains oriC1 at mid-cell, leading to the subcellular separation of the two ch1 replication arms. We further show that parS1 sites ectopically inserted in chromosome 2 (ch2) stabilize the inheritance of this replicon in the absence of its endogenous partition system, even without HubP. We also observe the positioning interference between oriC1 and oriC of ch2 regions when their positionings are both driven by ParABS1. Altogether, these data indicate that ParABS1 remains functional in the absence of HubP, which raises questions about the role of the polar anchoring of oriC1 in the cell cycle.

About 10% of bacteria have a multichromosome genome with a primary replicon of bacterial origin, called the chromosome, and other replicons of plasmid origin, the chromids. Studies on multichromosome bacteria revealed potential points of coordination between the replication/segregation of chromids and the progression of the cell cycle. For example, replication of the chromid of Vibrionales (called Chr2) is initiated upon duplication of a sequence carried by the primary chromosome (called Chr1), in such a way that replication of both replicons is completed synchronously. Also, Chr2 uses the Chr1 as a scaffold for its partition in the daughter cells. How many of the features detected so far are required for the proper integration of a secondary chromosome in the cell cycle? How many more features remain to be discovered? We hypothesized that critical features for the integration of the replication/segregation of a given chromid within the cell cycle program would be conserved independently of the species in which the chromid has settled. Hence, we searched for a chromid related to that found in Vibrionales outside of this order. We identified one in Plesiomonas shigelloides, an aquatic and pathogenic enterobacterium that diverged early within the clade of Enterobacterales. Our results suggest that the chromids present in P. shigelloides and Vibrionales derive from a common ancestor. We initiated in silico genomic and proteomic comparative analyses of P. shigelloides, Vibrionales, and Enterobacterales that enabled us to establish a list of features likely involved in the maintenance of the chromid within the host cell cycle.

Many mobile elements take advantage of the highly-conserved chromosome dimer resolution system of bacteria, Xer. They participate in the transmission of antibiotic resistance and pathogenicity determinants. In particular, the toxin-linked cryptic satellite phage (TLCΦ) plays an essential role in the continuous emergence of new toxigenic clones of the Vibrio cholerae strain at the origin of the ongoing 7th cholera pandemic. The Xer machinery is composed of two chromosomally-encoded tyrosine recombinases, XerC and XerD. They resolve chromosome dimers by adding a crossover between sister copies of a specific 28 base pair site of bacterial chromosomes, dif. The activity of XerD depends on a direct contact with a cell division protein, FtsK, which spatially and temporally constrains the process. TLCΦ encodes for a XerD-activation factor (XafT), which drives the integration of the phage into the dif site of the primary chromosome of V. cholerae independently of FtsK. However, XerD does not bind to the attachment site (attP) of TLCΦ, which raised questions on the integration process. Here, we compared the integration efficiency of thousands of synthetic mini-TLCΦ plasmids harbouring different attP sites and assessed their stability in vivo. In addition, we compared the efficiency with which XafT and the XerD activation domain of FtsK drive recombination reactions in vitro. Taken together, our results suggest that XafT promotes the formation of synaptic complexes between canonical Xer recombination sites and imperfect sites.

"Les architectes ne font pas des bâtiments, ils les imaginent et les dessinent." Cet ouvrage explore des situations, actuelles ou historiques, qui troublent cette division entre conception et construction. Il met ainsi en perspective une certaine tendance à la valorisation du « faire » à l’œuvre en architecture, à travers diverses pratiques :l’enseignement par la production à l’échelle 1:1, les expérimentations matérielles en situation de conception, l’esthétisa- tion des traces de la construction, le réemploi de matériaux, la fabrica- tion digitale, la construction en terre crue ou encore l’autoconstruction. Au fil des chapitres, l’ouvrage interroge les promesses du « faire » quant à d’autres rapports possibles à la matière, aux techniques, aux acteurs et à l’environnement. / "Architects do not make buildings, they design them." This book explores situ- ations, whether contemporary or historical, which challenge this division between design and construction. It investigates the growing prominence of making in architecture through a series of case-studies: design-build pedagogies, material experimentations in the design process, the aestheti- cization of traces of the construction, the use of reclaimed materials, digital fabrication, the crafts attached to raw-earth construction, or practices of self-building. Throughout its eleven chapters, the book interrogates the promises of making in terms of other possible relationships to materials, techniques, actors and the environment., info:eu-repo/semantics/published

Replicative helicases are essential proteins that unwind DNA in front of replication forks. Their loading depends on accessory proteins and in bacteria, DnaC and DnaI are well characterized loaders. However, most bacteria do not express either of these two proteins. Instead, they are proposed to rely on DciA, an ancestral protein unrelated to DnaC/I. While the DciA structure from Vibrio cholerae shares no homology with DnaC, it reveals similarities with DnaA and DnaX, two proteins involved during replication initiation. As other bacterial replicative helicases, VcDnaB adopts a toroid-shaped homo-hexameric structure, but with a slightly open dynamic conformation in the free state. We show that VcDnaB can load itself on DNA in vitro and that VcDciA stimulates this function, resulting in an increased DNA unwinding. VcDciA interacts with VcDnaB with a 3/6 stoichiometry and we show that a determinant residue, which discriminates DciA- and DnaC/I-helicases, is critical in vivo. Our work is the first step toward the understanding of the ancestral mode of loading of bacterial replicative helicases on DNA. It sheds light on the strategy employed by phage helicase loaders to hijack bacterial replicative helicases and may explain the recurrent domestication of dnaC/I through evolution in bacteria., Graphical Abstract Graphical AbstractDciA is the antecedent but unrelated to the helicase loaders DnaC/I. Structurally, the N-terminal domain of DciA is related to the NTD of DnaA, whereas its CTD is unfolded. DciA associates with DnaB according to a 3/6 stoichiometry which loads the helicase more efficiently on DNA. We identified in DnaB proteins a determinant residue that discriminates DciA- and DnaC/I-helicases and which happens to be critical in vivo. The determinant residue is located at the center of the DciA binding site.

L’architecture est une discipline du projet qui fait appel, dans des situations de conception complexe, à des compétences sociocognitives telles que l’écoute, le leadership, l’empathie, la médiation ... souvent peu explicitées dans les parcours de formation. Cet article propose de partager une expérience pédagogique visant à enseigner ces compétences par un dispositif pédagogique basé sur l’apprentissage expérientiel et le live project. En prenant appui sur cinq années de productions de rapports réflexifs par les étudiants, il tente de mettre en évidence les apprentissages effectifs et prises de conscience des étudiants sur les enjeux et compétences liés au travail collaboratif.

International audience

It is well established that DNA double-strand break (DSB) repair is required to underpin chromosomal DNA replication. Because DNA replication forks are prone to breakage, faithful DSB repair and correct replication fork restart are critically important. Cells, where the proteins required for DSB repair are absent or altered, display characteristic disturbances to genome replication. In this review, we analyze how bacterial DNA replication is perturbed in DSB repair mutant strains and explore the consequences of these perturbations for bacterial chromosome segregation and cell viability. Importantly, we look at how DNA replication and DSB repair processes are implicated in the striking recent observations of DNA amplification and DNA loss in the chromosome terminus of various mutant Escherichia coli strains. We also address the mutant conditions required for the remarkable ability to copy the entire E. coli genome, and to maintain cell viability, even in the absence of replication initiation from oriC, the unique origin of DNA replication in wild type cells. Furthermore, we discuss the models that have been proposed to explain these phenomena and assess how these models fit with the observed data, provide new insights and enhance our understanding of chromosomal replication and termination in bacteria., The close relationship between bacterial DNA replication and DNA double-strand break (DSB) repair is reviewed here, paying particular attention to recent research in Escherichia coli that has revealed two phenomena: DNA amplification of the chromosome terminus due to aberrant reactions in some DSB repair mutants and DNA loss in the chromosome terminus of DSB repair defective mutants.

Background: Prosthetic vascular graft infection (PVGI) remains a severe and challenging complication in vascular surgery with high morbidity and mortality rates. Incidence has been reported between 1% and 6%. The aim of this study was to report our experience in terms of general and surgical management as well as outcome, over 15 years. Methods: A retrospective consecutive study was conducted of all patients treated in our department for PVGI between January 2000 and December 2015. We analyzed all data relative to primary operation, duration interval between initial surgery and infections signs, infection site, type of microorganism involved, and surgical treatment modality, as well as evaluation of short- and long-term results. Results: Sixty-two patients were admitted for PVGI. Primary revascularization procedures consisted of a peripheral bypass in 42 (68%) patients and an aortic bypass in the remaining 20 (32%) patients. Median interval between primary procedure and reintervention was 3 months (interquartile range 17 [IQR 17]) in the peripheral group and 48 months (IQR 70.5) in the aortic group. Complete excision of the prosthetic graft was carried out in 85% of the cases. Thirty-day mortality was 0% and 9.5% in the aortic and peripheral group, respectively. The overall survival rate was 62.3% at 2-years, 46.4% in the aortic group, and 69.7% in the peripheral group. Conclusions: Prosthetic vascular graft infection needs a multidisciplinary management with appropriate antibiotherapy, radical removal of the infected graft, and in situ reconstruction. This strategy gives satisfactory results in terms of mortality, morbidity, patency rates, and infection control.

International audience; La communication s’attachera à présenter le projet pédagogique « Jardin d’Expériences » (« JExp’ ») qui s’appuie sur un principe d’apprentissage « design and build» Cette activité a été initiée en 2016 au sein de la FA+U (Faculté d’Architecture et d’Urbanisme de Mons). A travers un chantier d’aménagement, le « JExp’ » donne la liberté aux étudiants architectes de tester ensemble la matière et de confronter leurs concepts à la réalité du terrain. Echanges et partages in situ sont ainsi au cœur du système d’apprentissage dans l’objectif de développer une adaptabilité personnelle, gage d’un savoir-faire et savoir-être futur.

International audience; L’architecture est une discipline du projet qui fait appel, dans des situations de conception complexe, à des compétences sociocognitives telles que l’écoute, le leadership, l’empathie, la médiation ... souvent peu explicitées dans les parcours de formation. Cet article propose de partager une expérience pédagogique visant à enseigner ces compétences par un dispositif pédagogique basé sur l’apprentissage expérientiel et le « live project ». En prenant appui sur 4 années de productions de rapports réflexifs par les étudiants, il tente de mettre en évidence les apprentissages effectifs et prises de conscience des étudiants sur les enjeux et compétences liés au travail collaboratif.

Lung transplantation is a lifesaving treatment in numerous forms of end-stage lung disease but organ shortage remains nowadays his biggest issue. Ex vivo lung perfusion (EVLP) has recently emerged as a solution to this problem and begins to be accepted is clinical practice. In this review, we will focus on his experience worldwide. We would like to describe the technique and the criteria used to select the donors and the transplantable lungs. We will also browse the acceptance rate described in literature as well as numerous other aspects of this new tool. ispartof: JOURNAL OF THORACIC DISEASE vol:11 issue:4 pages:1635-1650 ispartof: location:China status: published

The Belgian Income Tax Code (the‘BITC’) originatesfrom the new legislation adopted after the World War Iand, more specifically, the law of 29 October 1919.1As aresult, this fundamental piece of legislation underlyingthe Belgian income tax system is celebrating its 100thanniversary.In consideration of that occasion, this article describesthe rationale of the Law of 1919 and how it was affectedby the other major income tax reform in Belgium in thetwentieth century (1962). It concludes by discussingwhether fundamental reforms are to be expected in thisarea in the near future.