Different rates of spontaneous mutation of chloroplastic and nuclear viroids as determined by high-fidelity ultra-deep sequencing

[EN] Mutation rates vary by orders of magnitude across biological systems, being higher for simpler genomes. The simplest known genomes correspond to viroids, subviral plant replicons constituted by circular non-coding RNAs of few hundred bases. Previous work has revealed an extremely high mutation rate for chrysanthemum chlorotic mottle viroid, a chloroplastreplicating viroid. However, whether this is a general feature of viroids remains unclear. Here, we have used high-fidelity ultra-deep sequencing to determine the mutation rate in a common host (eggplant) of two viroids, each representative of one family: the chloroplastic eggplant latent viroid (ELVd, Avsunviroidae) and the nuclear potato spindle tuber viroid (PSTVd, Pospiviroidae). This revealed higher mutation frequencies in ELVd than in PSTVd, as well as marked differences in the types of mutations produced. Rates of spontaneous mutation, quantified in vivo using the lethal mutation method, ranged from 1/1000 to 1/800 for ELVd and from 1/7000 to 1/3800 for PSTVd depending on sequencing run. These results suggest that extremely high mutability is a common feature of chloroplastic viroids, whereas the mutation rates of PSTVd and potentially other nuclear viroids appear significantly lower and closer to those of some RNA viruses.This work was supported by the European Research Council (erc.europa.eu; ERC-2011-StG-281191-VIRMUT to RS), the Spanish Ministerio de Economia y Competitividad (www.mineco.gob.es; BFU2013-41329 grant to RS, BFU2014-56812-P grant to RF, and a predoctoral fellowship to ALC), and the Spanish Junta de Comunidades de Castilla-La Mancha (www.castillalamancha.es;postdoctoral fellowship to CB). 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Involvement of the Chloroplastic Isoform of tRNA Ligase in the Replication of Viroids Belonging to the Family Avsunviroidae

Avocado sunblotch viroid, peach latent mosaic viroid, chrysanthemum chlorotic mottle viroid, and eggplant latent viroid (ELVd), the four recognized members of the family Avsunviroidae, replicate through the symmetric pathway of an RNA-to-RNA rolling-circle mechanism in chloroplasts of infected cells. Viroid oligomeric transcripts of both polarities contain embedded hammerhead ribozymes that, during replication, mediate their self-cleavage to monomeric-length RNAs with 5'-hydroxyl and 2',3'-phosphodiester termini that are subsequently circularized. We report that a recombinant version of the chloroplastic isoform of the tRNA ligase from eggplant (Solanum melongena L.) efficiently catalyzes in vitro circularization of the plus [(+)] and minus [(-)] monomeric linear replication intermediates from the four Avsunviroidae. We also show that while this RNA ligase specifically recognizes the genuine monomeric linear (+) ELVd replication intermediate, it does not do so with five other monomeric linear (+) ELVd RNAs with their ends mapping at different sites along the molecule, despite containing the same 5'-hydroxyl and 2',3'-phosphodiester terminal groups. Moreover, experiments involving transient expression of a dimeric (+) ELVd transcript in Nicotiana benthamiana Domin plants preinoculated with a tobacco rattle virus-derived vector to induce silencing of the plant endogenous tRNA ligase show a significant reduction of ELVd circularization. In contrast, circularization of a viroid replicating in the nucleus occurring through a different pathway is unaffected. Together, these results support the conclusion that the chloroplastic isoform of the plant tRNA ligase is the host enzyme mediating circularization of both (+) and (-) monomeric linear intermediates during replication of the viroids belonging to the family Avsunviroidae.This work was supported by the Ministerio de Ciencia e Innovacion (MICINN) from Spain through grants BIO2008-01986, BIO2011-26741, and BFU2008-03154. M. A. Nohales and D. Molina-Serrano were the recipients of predoctoral fellowships from the Spanish Ministerio de Educacion y Ciencia.Nohales Zafra, MA.; Molina Serrano, D.; Flores Pedauye, R.; Daros Arnau, JA. (2012). Involvement of the Chloroplastic Isoform of tRNA Ligase in the Replication of Viroids Belonging to the Family Avsunviroidae. Journal of Virology. 86:8269-8276. https://doi.org/10.1128/JVI.00629-12S8269827686Abelson, J., Trotta, C. R., & Li, H. (1998). tRNA Splicing. 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Evolution of the use of corticosteroids for the treatment of hospitalised COVID-19 patients in Spain between March and November 2020: SEMI-COVID national registry

Objectives: Since the results of the RECOVERY trial, WHO recommendations about the use of corticosteroids (CTs) in COVID-19 have changed. The aim of the study is to analyse the evolutive use of CTs in Spain during the pandemic to assess the potential influence of new recommendations. Material and methods: A retrospective, descriptive, and observational study was conducted on adults hospitalised due to COVID-19 in Spain who were included in the SEMI-COVID- 19 Registry from March to November 2020. Results: CTs were used in 6053 (36.21%) of the included patients. The patients were older (mean (SD)) (69.6 (14.6) vs. 66.0 (16.8) years; p < 0.001), with hypertension (57.0% vs. 47.7%; p < 0.001), obesity (26.4% vs. 19.3%; p < 0.0001), and multimorbidity prevalence (20.6% vs. 16.1%; p < 0.001). These patients had higher values (mean (95% CI)) of C-reactive protein (CRP) (86 (32.7-160) vs. 49.3 (16-109) mg/dL; p < 0.001), ferritin (791 (393-1534) vs. 470 (236- 996) µg/dL; p < 0.001), D dimer (750 (430-1400) vs. 617 (345-1180) µg/dL; p < 0.001), and lower Sp02/Fi02 (266 (91.1) vs. 301 (101); p < 0.001). Since June 2020, there was an increment in the use of CTs (March vs. September; p < 0.001). Overall, 20% did not receive steroids, and 40% received less than 200 mg accumulated prednisone equivalent dose (APED). Severe patients are treated with higher doses. The mortality benefit was observed in patients with oxygen saturation </=90%. Conclusions: Patients with greater comorbidity, severity, and inflammatory markers were those treated with CTs. In severe patients, there is a trend towards the use of higher doses. The mortality benefit was observed in patients with oxygen saturation </=90%

Rheological study of gel phenomena during epoxide network formation in the presence of sepiolite

The dynamic behaviour during the crosslinking of an epoxy polymer near the gel point was monitored using rheological multiple frequency experiments. The influence of a needle-shaped inorganic nanofiller, sepiolite, either non-modified or organically surface modified during the cure process in the presence of an aliphatic and an aromatic hardener was investigated. The validity of various criteria for determining the gel point was examined for the crosslinking of these filled thermosets. The Winter-Chambon criterion at the gel point is obeyed by the unfilled and by the non-modified sepiolite-filled epoxy matrix with either of the two hardeners. However, physical gels are formed in the presence of the organically modified sepiolite and the Winter-Chambon criterion is not valid. For all the systems investigated, the nanofiller reduces the time to reach gelation. Critical relaxation exponents and gel strength have been determined indicating a more elastic and stronger gel in the presence of the aliphatic hardener.Peer Reviewe

The Role of Diisocyanate Structure to Modify Properties of Segmented Polyurethanes

Segmented thermoplastic polyurethanes (PU) were synthetized using a polycarbonatediol macrodiol as a flexible or soft segment with a molar mass of 2000 g/mol, and different diisocyanate molecules and 1,4-butanediol as a rigid or hard segment. The diisocyanate molecules employed are 3,3′-Dimethyl-4,4′-biphenyl diisocyanate (TODI), 4,4′-diphenylmethane diisocyanate (MDI), 4,4′-Methylenebis(phenyl isocyanate) 1-isocyanato-4-[(4-phenylisocyanate)methyl]benzene and 1-isocyanate-4-[(2-phenylisocyanate) methyl]benzene (ratio 1:1) (MDIi), isophorone diisocyanate (IPDI), and hexamethylene diisocyanate (HDI). The polyurethanes obtained reveal a wide variation of microphase separation degree that is correlated with mechanical properties. Different techniques, such as DSC, DMA, and FTIR, have been used to determine flexible–rigid segment phase behavior. Mechanical properties, such as tensile properties, Shore D hardness, and “compression set”, have been determined. This work reveals that the structure of the hard segment is crucial to determine the degree of phase miscibility which affects the resulting mechanical properties, such as tensile properties, hardness, and “compression set”

Morphology, flexural, and thermal properties of sepiolite modified epoxy resins with different curing agents

A bisphenol A-based epoxy resin was modified with 5 wt% organically modified sepiolite (Pangel B40) and thermally cured using two different curing agents: an aliphatic diamine (Jeffamine D230, D230) and a cycloaliphatic diamine (3DCM). The morphology of the cured materials was established by scanning and transmission electron microscopy analysis. The thermal stability, thermo-mechanical properties, and flexural behaviour of the sepiolite-modified matrices were evaluated and compared with the corresponding neat matrix. The initial thermal decomposition temperature did not change with the addition of sepiolite. The flexural modulus of the epoxy matrix slightly increases by the incorporation of the organophilic sepiolite. The flexural strength of the sepiolite modified resin cured with D230 increased by a 10% while the sepiolite modified resin cured with 3DCM resulted in a lower flexural strength compared with the unmodified resin. The reduced flexural strength was attributed to the stress concentrations caused by the sepiolite modifier, which rendered the resins more brittle.Fil: Nohales, Andres. Universidad de Valencia; EspañaFil: Solar, Lorena. Universidad de Valencia; EspañaFil: Porcar, Iolanda. Universidad de Valencia; EspañaFil: Vallo, Claudia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Gómez, Clara M.. Universidad de Valencia; Españ

Mental health in hospitals: A cross-sectional study of the representations of professionals in a French university hospital: Considering mental health is essential for the individual and society. Healthcare professionals are at risk of poor mental health. On the occasion of WHO World Mental Health Day on October 10th, 2021, a survey was conducted by the Occupational Health Service and the Direction of quality in Healthcare of the University Hospital of Lyon (Hospices civils de Lyon, HCL). The aim of the study was to collect the representations and beliefs of hospital staff on the/their mental health. Methods: A short and anonymous questionnaire was sent electronically to the 22,904 HCL professionals, with a link towards a short educational video. Results: Seven hundred and sixty-six responses were collected. Representations of mental health were generally positive among professionals, with a transactional vision including known determinants such as living and working conditions. The most chosen words related to mental health were ?equilibrium? and ?well-being?. The measures considered to be the most relevant by professionals to promote mental health were the establishment of rest ?bubble? times, times for discussions (colleagues and management), prevention programs, easier access to a ?psy? and to the occupational health service. Conclusion: This survey contributed to a better understanding of the representations of HCL professionals regarding mental health and to their awareness in this field. These results can be used to develop a mental health promotion plan in the workplace, adapted to hospital professionals.

Considering mental health is essential for the individual and society. Healthcare professionals are at risk of poor mental health. On the occasion of WHO World Mental Health Day on October 10th, 2021, a survey was conducted by the Occupational Health Service and the Direction of quality in Healthcare of the University Hospital of Lyon (Hospices civils de Lyon, HCL). The aim of the study was to collect the representations and beliefs of hospital staff on the/their mental health.La prise en considération de la santé mentale est essentielle pour l'individu et la société. Les professionnels de santé sont à risque d'une santé mentale dégradée. À l'occasion de la Journée mondiale de la santé mentale de l'OMS le 10 octobre 2021, une enquête a été conduite par le Service de médecine et santé au travail (SMST) et la Direction qualité usagers et santé populationnelle (DQUSP) des Hospices civiles de Lyon (HCL). L'objectif était de recueillir les représentations et croyances des personnels hospitaliers sur la/leur santé mentale. Méthode: Un questionnaire court et anonyme a été adressé par voie électronique aux 22 904 professionnels des HCL, accompagné d'une courte vidéo pédagogique. Résultats: Au total, 766 réponses ont été recueillies. Les représentations de la santé mentale étaient globalement positives parmi les professionnels, avec une vision transactionnelle incluant les déterminants connus comme les conditions de vie et de travail. Les mots les plus choisis en lien avec la santé mentale étaient « équilibre » et « bien-être ». Les mesures considérées comme les plus pertinentes pour promouvoir la santé mentale par les professionnels étaient la mise en place de temps de « bulle » de repos, des temps d'échanges (collègues et encadrement), des programmes de prévention, l'accès facilité à un(e) « psy » et au service de médecine et santé au travail. Conclusion: Cette enquête a contribué à mieux connaître les représentations des professionnels des HCL quant à la/leur santé mentale, et a participé à leur sensibilisation dans ce domaine. Ces résultats pourront participer à élaborer un plan de promotion de la santé mentale au travail adapté aux professionnels hospitaliers