Thermodynamic modeling of phase separation in manganites

We present a phenomenological model based on the thermodynamics of the phase separated state of manganites, accounting for its static and dynamic properties. Through calorimetric measurements on La$_{0.225}$Pr$_{0.40}$Ca$_{0.375}$MnO$_{3}$ the low temperature free energies of the coexisting ferromagnetic and charge ordered phases are evaluated. The phase separated state is modeled by free energy densities uniformly spread over the sample volume. The calculations contemplate the out of equilibrium features of the coexisting phase regime, to allow a comparison between magnetic measurements and the predictions of the model. A phase diagram including the static and dynamic properties of the system is constructed, showing the existence of blocked and unblocked regimes which are characteristics of the phase separated state in manganites.Comment: 7 pages, 5 figures, Submitted to Phys. Rev.

Rational stabilization of complex proteins: A divide and combine approach

© 2015, Macmillan Publishers Limited. All rights reserved. Increasing the thermostability of proteins is often crucial for their successful use as analytic, synthetic or therapeutic tools. Most rational thermostabilization strategies were developed on small two-state proteins and, unsurprisingly, they tend to fail when applied to the much more abundant, larger, non-fully cooperative proteins. We show that the key to stabilize the latter is to know the regions of lower stability. To prove it, we have engineered apoflavodoxin, a non-fully cooperative protein on which previous thermostabilizing attempts had failed. We use a step-wise combination of structure-based, rationally-designed, stabilizing mutations confined to the less stable structural region, and obtain variants that, according to their van't Hoff to calorimetric enthalpy ratios, exhibit fully-cooperative thermal unfolding with a melting temperature of 75°C, 32 degrees above the lower melting temperature of the non-cooperative wild type protein. The ideas introduced here may also be useful for the thermostabilization of complex proteins through formulation or using specific stabilizing ligands (e.g. pharmacological chaperones).Peer Reviewe

A Quantitative Characterization of Nucleoplasmin/Histone Complexes Reveals Chaperone Versatility.

Nucleoplasmin (NP) is an abundant histone chaperone in vertebrate oocytes and embryos involved in storing and releasing maternal histones to establish and maintain the zygotic epigenome. NP has been considered a H2A-H2B histone chaperone, and recently it has been shown that it can also interact with H3-H4. However, its interaction with different types of histones has not been quantitatively studied so far. We show here that NP binds H2A-H2B, H3-H4 and linker histones with Kd values in the subnanomolar range, forming different complexes. Post-translational modifications of NP regulate exposure of the polyGlu tract at the disordered distal face of the protein and induce an increase in chaperone affinity for all histones. The relative affinity of NP for H2A-H2B and linker histones and the fact that they interact with the distal face of the chaperone could explain their competition for chaperone binding, a relevant process in NP-mediated sperm chromatin remodelling during fertilization. Our data show that NP binds H3-H4 tetramers in a nucleosomal conformation and dimers, transferring them to DNA to form disomes and tetrasomes. This finding might be relevant to elucidate the role of NP in chromatin disassembly and assembly during replication and transcription

Edoxaban Versus Low-Molecular-Weight Heparin in Hospitalized COVID-19 Patients With Atrial Fibrillation

COVID-19; Atrial fibrillation; EdoxabanCOVID-19; Fibrilación auricular; EdoxabanCOVID-19; Fibril·lació auricular; EdoxabanObjective During the first wave of the SARS-CoV-2 pandemic, management of anticoagulation therapy in hospitalized patients with atrial fibrillation (AF) was simplified to low-molecular-weight heparin (LMWH) followed by oral anticoagulation, mainly owing to the risk of drug–drug interactions. However, not all oral anticoagulants carry the same risk. Methods Observational, retrospective, and multicenter study that consecutively included hospitalized patients with AF anticoagulated with LMWH followed by oral anticoagulation or edoxaban concomitantly with empirical COVID-19 therapy. Time-to-event (mortality, total bleeds, and admissions to ICU) curves, using an unadjusted Kaplan-Meier method and Cox regression model adjusted for potential confounders were constructed. Results A total of 232 patients were included (80.3 ± 7.7 years, 50.0% men, CHA2DS2-VASc 4.1 ± 1.4; HAS-BLED 2.6 ± 1.0). During hospitalization, patients were taking azithromycin (98.7%), hydroxychloroquine (89.7%), and ritonavir/lopinavir (81.5%). The mean length of hospital stay was 14.6 ± 7.2 days, and total follow-up was 31.6 ± 13.4 days; 12.9% of patients required admission to ICU, 18.5% died, and 9.9% had a bleeding complication (34.8% major bleeding). Length of hospital stay was longer in patients taking LMWH (16.0 ± 7.7 vs 13.3 ± 6.5 days; P = .005), but mortality and total bleeds were similar in patients treated with edoxaban and those treated with LMWH followed by oral anticoagulation. Conclusions Mortality rates, arterial and venous thromboembolic complications, and bleeds did not significantly differ between AF patients receiving anticoagulation therapy with edoxaban or LMWH followed by oral anticoagulation. However, the duration of hospitalization was significantly lower with edoxaban. Edoxaban had a similar therapeutic profile to LMWH followed by oral anticoagulation and may provide additional benefits

The origin and correlated evolution of symbiosis and coloniality in Scleractinian corals

Symbiosis and coloniality are ecologically important traits for corals of the order Scleractinia. Symbiotic (zooxanthellate) species are highly successful in shallow waters of tropical and subtropical seas and most of them are colonial. On the other hand, azooxanthellate species present wide distribution ranges and expand to the deep-sea at more than 6,000 m depth. These are mostly solitary, with only few species colonial that form extensive deep reefs. Each ecologically distinctive group encompasses half of the biodiversity of the order and they are not grouped into differentiated monophyletic clades. Paleontologists and evolutionary biologists have debated for decades whether modern scleractinian corals have evolved from symbiotic or colonial ancestors and how these traits have evolved and being involved in the diversification process in corals. Previous comparative analyses throw evidence in favor of coevolution of these characters and toward repetitive loss of symbiosis and coloniality. Nevertheless, the discovery of the origin of the group deep in the Paleozoic, with a deep divergent clade composed of only azooxanthellate corals has questioned these findings. With this work, we disentangle the patterns in the evolution of symbiosis and coloniality, testing if they are correlated and if they follow a gradual or episodic mode of evolution. To this end, we first produce the most complete time-calibrated phylogenetic tree for the order Scleractinia, including new sequences of never-before sampled species and genera. These novel sequences contribute to alleviate the current molecular under sampling of azooxanthellate species. Incorporating phylogenetic uncertainty, we obtained strong evidence in favor of a correlated and episodic model of evolution. This model led to the inference of an azooxanthellate and solitary most recent ancestor of scleractinians. Transition rates between the four different combinations of the two traits showed that while coloniality is gained and lost multiple times, symbiosis first appears around 282 Ma and is never lost. Also, coloniality seems to have appeared before symbiosis in azooxanthellate lineages. Thus, azooxanthellate corals, and especially colonial lineages, have been acting as a source of biodiversity for shallow zooxanthellate coral communities, highlighting the uniqueness of shallow and deep species and the need to preserve them

CARB-ES-19 Multicenter Study of Carbapenemase-Producing Klebsiella pneumoniae and Escherichia coli From All Spanish Provinces Reveals Interregional Spread of High-Risk Clones Such as ST307/OXA-48 and ST512/KPC-3

Carbapenemases; High-risk clones; Whole genome sequencingCarbapenemasas; Clones de alto riesgo; Secuenciación del genoma completoCarbapenemases; Clons d'alt risc; Seqüenciació del genoma sencerObjectives: CARB-ES-19 is a comprehensive, multicenter, nationwide study integrating whole-genome sequencing (WGS) in the surveillance of carbapenemase-producing K. pneumoniae (CP-Kpn) and E. coli (CP-Eco) to determine their incidence, geographical distribution, phylogeny, and resistance mechanisms in Spain. Methods: In total, 71 hospitals, representing all 50 Spanish provinces, collected the first 10 isolates per hospital (February to May 2019); CPE isolates were first identified according to EUCAST (meropenem MIC > 0.12 mg/L with immunochromatography, colorimetric tests, carbapenem inactivation, or carbapenem hydrolysis with MALDI-TOF). Prevalence and incidence were calculated according to population denominators. Antibiotic susceptibility testing was performed using the microdilution method (EUCAST). All 403 isolates collected were sequenced for high-resolution single-nucleotide polymorphism (SNP) typing, core genome multilocus sequence typing (cgMLST), and resistome analysis. Results: In total, 377 (93.5%) CP-Kpn and 26 (6.5%) CP-Eco isolates were collected from 62 (87.3%) hospitals in 46 (92%) provinces. CP-Kpn was more prevalent in the blood (5.8%, 50/853) than in the urine (1.4%, 201/14,464). The cumulative incidence for both CP-Kpn and CP-Eco was 0.05 per 100 admitted patients. The main carbapenemase genes identified in CP-Kpn were blaOXA–48 (263/377), blaKPC–3 (62/377), blaVIM–1 (28/377), and blaNDM–1 (12/377). All isolates were susceptible to at least two antibiotics. Interregional dissemination of eight high-risk CP-Kpn clones was detected, mainly ST307/OXA-48 (16.4%), ST11/OXA-48 (16.4%), and ST512-ST258/KPC (13.8%). ST512/KPC and ST15/OXA-48 were the most frequent bacteremia-causative clones. The average number of acquired resistance genes was higher in CP-Kpn (7.9) than in CP-Eco (5.5). Conclusion: This study serves as a first step toward WGS integration in the surveillance of carbapenemase-producing Enterobacterales in Spain. We detected important epidemiological changes, including increased CP-Kpn and CP-Eco prevalence and incidence compared to previous studies, wide interregional dissemination, and increased dissemination of high-risk clones, such as ST307/OXA-48 and ST512/KPC-3.This research was supported by grants from the Instituto de Salud Carlos III (numbers PI18CIII/00030 and PI21CIII/00039). It was also supported by Plan Nacional de I + D + i 2013–2016, Instituto de Salud Carlos III, Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Economía y Competitividad, Spanish Network for Research in Infectious Diseases (grants RD16CIII/0004/0002, RD16/0016/0001, RD16/0016/0003, RD16/0016/0004, RD16/0016/0006, RD16/0016/0007, RD16/0016/0008, RD16/0016/0010, and RD16/0016/0011). Cofinanced by the European Development Regional Fund “A way to achieve Europe,” Operative Program Intelligent Growth 2014–2020. CIBER – Consorcio Centro de Investigación Biomédica en Red (CB21/13/00095, CB21/13/00012, CB21/13/00049, CB21/13/00054, CB21/13/00055, CB21/13/00068, CB21/13/00081, CB21/13/00084, and CB21/13/00099) (CIBERINFEC) and Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación and Unión Europea – NextGenerationEU also supported this work

Impact of New Onset Atrial Fibrillation in Hospitalized Patients with COVID-19: Results of the “ACO-VID” Registry

COVID-19; Anticoagulation; Atrial fibrillationCOVID-19; Anticoagulación; Fibrilación auricularCOVID-19; Anticoagulació; Fibril·lació auricularObjective To assess the impact of new-onset atrial fibrillation (AF) on patients hospitalized with coronavirus disease 2019 (COVID-19). Methods Multicenter and retrospective study that included subjects >55 years hospitalized with COVID-19 from March to October 2020 in Spanish hospitals. Patients were divided into 3 groups (no AF, new-onset AF, and preexisting AF) and followed-up to 90 days. Results A total of 668 patients were included, of whom 162 (24.3%) had no AF, 107 (16.0%) new-onset AF and 399 (59.7%) preexisting AF. Compared to patients without AF, those patients with new-onset AF were older and had more comorbidities, but without differences with preexisting AF. During hospitalization, in the univariate analysis, compared to patients without AF, major bleeding and cardiovascular mortality were more frequent in patients with new-onset AF (10.3% vs 0.6%; P < .001; 2.8% vs 0.6%; P = .025, respectively), with a trend toward more stroke (1.9% vs 0%; P = .085). Outcomes were similar between AF groups, but the length of stay was greater in preexisting AF patients. Among patients with new-onset AF taking reduced doses of anticoagulant treatment was associated with higher risks of stroke and major bleeding. Conclusions In COVID-19 hospitalized patients, new-onset AF may be associated with worse outcomes, but influenced by the dose of anticoagulants.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Fundación para la Formación e Investigación Sanitarias de la Región de Murcia, though an unrestricted grant from Daichii Sankyo (DS) Spain. DS had no role in the design, analysis, interpretation and publication of the registry

Maternal body weight and gestational diabetes differentially influence placental and pregnancy outcomes

Context: Maternal obesity and gestational diabetes mellitus (GDM) can both contribute to adverse neonatal outcomes. The extent to which this may be mediated by differences in placental metabolism and nutrient transport remains to be determined. Objective: Our objective was to examine whether raised maternal body mass index (BMI) and/or GDM contributed to a resetting of the expression of genes within the placenta that are involved in energy sensing, oxidative stress, inflammation, and metabolic pathways. Methods: Pregnant women from Spain were recruited as part of the “Study of Maternal Nutrition and Genetics on the Foetal Adiposity Programming” survey at the first antenatal visit (12–20 weeks of gestation) and stratified according to prepregnancy BMI and the incidence of GDM. At delivery, placenta and cord blood were sampled and newborn anthropometry measured. Results: Obese women with GDM had higher estimated fetal weight at 34 gestational weeks and a greater risk of preterm deliveries and cesarean section. Birth weight was unaffected by BMI or GDM; however, women who were obese with normal glucose tolerance had increased placental weight and higher plasma glucose and leptin at term. Gene expression for markers of placental energy sensing and oxidative stress, were primarily affected by maternal obesity as mTOR was reduced, whereas SIRT-1 and UCP2 were both upregulated. In placenta from obese women with GDM, gene expression for AMPK was also reduced, whereas the downstream regulator of mTOR, p70S6KB1 was raised. Conclusions: Placental gene expression is sensitive to both maternal obesity and GDM which both impact on energy sensing and could modulate the effect of either raised maternal BMI or GDM on birth weight