Genome characteristics of facultatively symbiotic Frankia sp. strains reflect host range and host plant biogeography

Soil bacteria that also form mutualistic symbioses in plants encounter two major levels of selection. One occurs during adaptation to and survival in soil, and the other occurs in concert with host plant speciation and adaptation. Actinobacteria from the genus Frankia are facultative symbionts that form N2-fixing root nodules on diverse and globally distributed angiosperms in the “actinorhizal” symbioses. Three closely related clades of Frankia sp. strains are recognized; members of each clade infect a subset of plants from among eight angiosperm families. We sequenced the genomes from three strains; their sizes varied from 5.43 Mbp for a narrow host range strain (Frankia sp. strain HFPCcI3) to 7.50 Mbp for a medium host range strain (Frankia alni strain ACN14a) to 9.04 Mbp for a broad host range strain (Frankia sp. strain EAN1pec.) This size divergence is the largest yet reported for such closely related soil bacteria (97.8%–98.9% identity of 16S rRNA genes). The extent of gene deletion, duplication, and acquisition is in concert with the biogeographic history of the symbioses and host plant speciation. Host plant isolation favored genome contraction, whereas host plant diversification favored genome expansion. The results support the idea that major genome expansions as well as reductions can occur in facultative symbiotic soil bacteria as they respond to new environments in the context of their symbioses

Variation in carbon and nitrogen concentrations among peatland categories at the global scale

Publisher Copyright: © 2022 This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.Peatlands account for 15 to 30% of the world's soil carbon (C) stock and are important controls over global nitrogen (N) cycles. However, C and N concentrations are known to vary among peatlands contributing to the uncertainty of global C inventories, but there are few global studies that relate peatland classification to peat chemistry. We analyzed 436 peat cores sampled in 24 countries across six continents and measured C, N, and organic matter (OM) content at three depths down to 70 cm. Sites were distinguished between northern (387) and tropical (49) peatlands and assigned to one of six distinct broadly recognized peatland categories that vary primarily along a pH gradient. Peat C and N concentrations, OM content, and C:N ratios differed significantly among peatland categories, but few differences in chemistry with depth were found within each category. Across all peatlands C and N concentrations in the 10-20 cm layer, were 440 ± 85.1 g kg-1 and 13.9 ± 7.4 g kg-1, with an average C:N ratio of 30.1 ± 20.8. Among peatland categories, median C concentrations were highest in bogs, poor fens and tropical swamps (446-532 g kg-1) and lowest in intermediate and extremely rich fens (375-414 g kg-1). The C:OM ratio in peat was similar across most peatland categories, except in deeper samples from ombrotrophic tropical peat swamps that were higher than other peatlands categories. Peat N concentrations and C:N ratios varied approximately two-fold among peatland categories and N concentrations tended to be higher (and C:N lower) in intermediate fens compared with other peatland types. This study reports on a unique data set and demonstrates that differences in peat C and OM concentrations among broadly classified peatland categories are predictable, which can aid future studies that use land cover assessments to refine global peatland C and N stocks.Peer reviewe

Élèves en troubles du comportement et climat de classe : comparaison entre deux environnements éducatifs

Cette étude compare l’évolution au cours d’une année scolaire de la perception du climat de classe selon 212 élèves québécois du troisième cycle du primaire (5e année) fréquentant, soit des classes spéciales pour élèves avec troubles du comportement, soit des classes ordinaires. L’étude s’intéresse plus spécifiquement au climat relationnel et au climat éducatif, ainsi qu’aux pratiques éducatives et à la prévalence de comportements inadaptés. Les résultats montrent que les élèves du primaire perçoivent un meilleur climat en classe ordinaire, et ce, malgré la dégradation en cours d’année de plusieurs des dimensions étudiées, notamment sur le plan de la relation avec l’enseignante et de leur compréhension des règles de vie en classe, alors que les élèves fréquentant les classes spéciales perçoivent plutôt une amélioration pour ces mêmes dimensions. Les résultats de l’étude sont discutés dans la perspective de l’évolution des besoins des préadolescents et l’encadrement des élèves présentant des troubles du comportement.This study compares the changes in the perception of class climate occurring across a school year in a sample of 212 Canadian students from fifth grade elementary school who attend either regular classes or special education classes. The dimensions studied consist more specifically in the perception of social climate, learning climate, teaching practices and prevalence of inappropriate behaviors. Our results show that elementary students who attend regular classes perceive a better overall climate than their counterparts from special education classes. However, it should be noted that the perception of the quality of the relationship with the teacher and the perception of the clarity of teacher’s expectations improve in special education classes while declining in regular classes. Those results are discussed in the perspective of the specific needs of preadolescents and the management of students with behavior problems

Angiotensin II induces apoptosis of human right and left ventricular endocardial endothelial cells by activating the AT2 receptor

Endocardial endothelial cells (EECs) form a monolayer lining the ventricular cavities. Studies from our laboratory and the literature have shown differences between EECs isolated from the right and left ventricles (EECRs and EECLs respectively). Angiotensin II (Ang II) was shown to induce apoptosis of different cell types mainly via AT1 receptor activation. In this study, we verified whether Ang II induces apoptosis of human EECRs and EECLs and via which type of receptor. Using the Annexin V labeling and in situ TUNEL assays, our results showed that Ang II-induced apoptosis of both hEECRs and hEECLs in a concentration-dependent manner. Our results using specific AT1 and AT2 receptor antagonists showed that the Ang II-induced apoptosis in both hEECRs and hEECLs is mediated mainly via the AT2 receptor. However, AT1 receptor blockade partially prevented Ang II-induced apoptosis, particularly in hEECRs. Hence, our results suggest that mainly AT2 receptors mediate Ang II-induced apoptosis of hEECRs and hEECLs. The damage of EECs would affect their function as a physical barrier between the blood and cardiomyocytes thus affecting cardiomyocyte functions.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Biomechanical effects of a lumbar support in a mattress

For many patients with chronic low back pain, the lack of sleep and sufficient rest period that allows some relaxation is a major obstacle to a good quality of life. During sleep periods, neuromuscular activity is at a minimal level. The major factor influencing the forces on the body, and particularly the spine, is gravity. The force of gravity is sufficient to deform soft tissues when the body is resting on a mattress. Thus, the goal of this study is to measure the contact pressure forces acting on the spine with and without an inflatable support in various experimental conditions. Our hypothesis is that a lumbar support will distribute the force of gravity more uniformly over the pelvic, lumbar and thoracic areas, maintaining the lumbar lordosis, in a supine posture. In this study, 10 participants were tested when lying supine in six separate experimental conditions. These conditions varied according to the surface (no mattress, foam, mattress) and the fact that the support was inflated or not. The dependent variable measured was the contact pressure. It was measured using a pressure sensor mat (Tekscan™). When the cushion was inflated the distribution of contact pressure in the different areas (pelvic, lumbar and thoracic) was modified. The comparison of the mean forces revealed that when the cushion was not inflated, the pressure distribution was mainly localized in the pelvic area. After the cushion was inflated, a significant decrease of contact pressure in the pelvic region and a significant increase in the lumbar area were observed. Our results confirm the hypothesis that a lumbar support inserted in a mattress allows a more homogenous distribution of contact pressure over the pelvic, lumbar and thoracic areas during supine posture. The use of an inflatable cushion favouring a transition of the contact pressure from the pelvic to the lumbar region could potentially limit unfavourable compressive and shearing forces acting on the lumbar spine

Une nouvelle stratégie pour stabiliser la normalisation de l’angiogenèse tumorale afin d’améliorer l’efficacité des traitements anti-cancéreux

International audienc

Une nouvelle stratégie pour stabiliser la normalisation de l’angiogenèse tumorale afin d’améliorer l’efficacité des traitements anti-cancéreux

International audienc

Novel Glycosynthons for Glycoconjugate Preparation: Oligosaccharylpyroglutamylanilide Derivatives

International audienceThe reducing sugar of an oligosaccharide reacting with the alpha-amino group of an amino acid is converted to an N-oligosaccharylamino acid which can then be stabilized by N-acylation. Oligosaccharides in solution in N,N-dimethylformamide reacted with alpha-glutamyl-p-nitroanilide at 50 degrees C for a few hours, leading to an N-oligosaccharylglutamyl-p-nitroanilide. Then, the gamma-carboxylic group of the glutamyl moiety, activated by adding (benzotriazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP), reacted with the substituted alpha-amino group of the glutamyl residue, leading to an N-oligosaccharylpyroglutamyl-p-nitroanilide within 0.5 h. Such a one-pot two-step reaction was shown to be very efficient in the case of a disaccharide such as lactose, or pentasaccharides such as lacto-N-fucopentaoses, Lewis(a) or Lewis(x). The glycosynthons were characterized by chromatography (HPAEC and HPLC); their molecular mass was determined by electrospray ionization mass spectrometry, and the glycosylamides were shown to have a beta-anomeric configuration on the basis of their proton NMR. The N-oligosaccharylpyroglutamyl-p-nitroanilides are quite stable at room temperature over a large pH range. They are easily converted to N-oligosaccharylpyroglutamyl-p-isothiocyanatoanilides which can be used to prepare glycoconjugates such as cationic glycosylated polylysines suitable for specifically delivering genes or oligonucleotides in a sugar-dependent manner