Observing the primary steps of ion solvation in helium droplets.

Solvation is a ubiquitous phenomenon in the natural sciences. At the macroscopic level, it is well understood through thermodynamics and chemical reaction kinetics1,2. At the atomic level, the primary steps of solvation are the attraction and binding of individual molecules or atoms of a solvent to molecules or ions of a solute1. These steps have, however, never been observed in real time. Here we instantly create a single sodium ion at the surface of a liquid helium nanodroplet3,4, and measure the number of solvent atoms that successively attach to the ion as a function of time. We found that the binding dynamics of the first five helium atoms is well described by a Poissonian process with a binding rate of 2.0 atoms per picosecond. This rate is consistent with time-dependent density-functional-theory simulations of the solvation process. Furthermore, our measurements enable an estimate of the energy removed from the region around the sodium ion as a function of time, revealing that half of the total solvation energy is dissipated after four picoseconds. Our experimental method opens possibilities for benchmarking theoretical models of ion solvation and for time-resolved measurements of cation-molecule complex formation.

Recombinant OC43 SARS-CoV-2 spike replacement virus: An improved BSL-2 proxy virus for SARS-CoV-2 neutralization assays.

We generated a replication-competent OC43 human seasonal coronavirus (CoV) expressing the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike in place of the native spike (rOC43-CoV2 S). This virus is highly attenuated relative to OC43 and SARS-CoV-2 in cultured cells and animals and is classified as a biosafety level 2 (BSL-2) agent by the NIH biosafety committee. Neutralization of rOC43-CoV2 S and SARS-CoV-2 by S-specific monoclonal antibodies and human sera is highly correlated, unlike recombinant vesicular stomatitis virus-CoV2 S. Single-dose immunization with rOC43-CoV2 S generates high levels of neutralizing antibodies against SARS-CoV-2 and fully protects human ACE2 transgenic mice from SARS-CoV-2 lethal challenge, despite nondetectable replication in respiratory and nonrespiratory organs. rOC43-CoV2 S induces S-specific serum and airway mucosal immunoglobulin A and IgG responses in rhesus macaques. rOC43-CoV2 S has enormous value as a BSL-2 agent to measure S-specific antibodies in the context of a bona fide CoV and is a candidate live attenuated SARS-CoV-2 mucosal vaccine that preferentially replicates in the upper airway.

Cell surface nucleocapsid protein expression: A betacoronavirus immunomodulatory strategy.

We recently reported that SARS-CoV-2 nucleocapsid (N) protein is abundantly expressed on the surface of both infected and neighboring uninfected cells, where it enables activation of Fc receptor-bearing immune cells with anti-N antibodies (Abs) and inhibits leukocyte chemotaxis by binding chemokines (CHKs). Here, we extend these findings to N from the common cold human coronavirus (HCoV)-OC43, which is also robustly expressed on the surface of infected and noninfected cells by binding heparan sulfate/heparin (HS/H). HCoV-OC43 N binds with high affinity to the same set of 11 human CHKs as SARS-CoV-2 N, but also to a nonoverlapping set of six cytokines. As with SARS-CoV-2 N, HCoV-OC43 N inhibits CXCL12ß-mediated leukocyte migration in chemotaxis assays, as do all highly pathogenic and common cold HCoV N proteins. Together, our findings indicate that cell surface HCoV N plays important evolutionarily conserved roles in manipulating host innate immunity and as a target for adaptive immunity.

Quantitative analysis of the GABAergic innervation of the soma and axon initial segment of pyramidal cells in the human and mouse neocortex.

Perisomatic GABAergic innervation in the cerebral cortex is carried out mostly by basket and chandelier cells, which differentially participate in the control of pyramidal cell action potential output and synchronization. These cells establish multiple synapses with the cell body (and proximal dendrites) and the axon initial segment (AIS) of pyramidal neurons, respectively. Using multiple immunofluorescence, confocal microscopy and 3D quantification techniques, we have estimated the number and density of GABAergic boutons on the cell body and AIS of pyramidal neurons located through cortical layers of the human and mouse neocortex. The results revealed, in both species, that there is clear variability across layers regarding the density and number of perisomatic GABAergic boutons. We found a positive linear correlation between the surface area of the soma, or the AIS, and the number of GABAergic terminals in apposition to these 2 neuronal domains. Furthermore, the density of perisomatic GABAergic boutons was higher in the human cortex than in the mouse. These results suggest a selectivity for the GABAergic innervation of the cell body and AIS that might be related to the different functional attributes of the microcircuits in which neurons from different layers are involved in both human and mouse.

Microanatomical study of pyramidal neurons in the contralesional somatosensory cortex after experimental ischemic stroke.

At present, many studies support the notion that after stroke, remote regions connected to the infarcted area are also affected and may contribute to functional outcome. In the present study, we have analyzed possible microanatomical alterations in pyramidal neurons from the contralesional hemisphere after induced stroke. We performed intracellular injections of Lucifer yellow in pyramidal neurons from layer III in the somatosensory cortex of the contralesional hemisphere in an ischemic stroke mouse model. A detailed 3-dimensional analysis of the neuronal complexity and morphological alterations of dendritic spines was then performed. Our results demonstrate that pyramidal neurons from layer III in the somatosensory cortex of the contralesional hemisphere show selective changes in their dendritic arbors, namely, less dendritic complexity of the apical dendritic arbor-but no changes in the basal dendritic arbor. In addition, we found differences in spine morphology in both apical and basal dendrites comparing the contralesional hemisphere with the lesional hemisphere. Our results show that pyramidal neurons of remote areas connected to the infarct zone exhibit a series of selective changes in neuronal complexity and morphological distribution of dendritic spines, supporting the hypothesis that remote regions connected to the peri-infarcted area are also affected after stroke.

Relative Match Load in Young Professional Soccer Players during Soccer-7 and Soccer-11.

The aim of this study was to analyze the differences in internal and external load during Soccer-7 and Soccer-11, comparing positional requirements and neuromuscular fatigue in both modalities. Twenty-four young soccer players were monitored in Soccer-7 and Soccer-11 matches using global positioning systems. Total distance covered (TD), distance covered at high speed (HSR), distance covered at very high speed (VHSR), peak speed, accelerations (Acc) and decelerations (Dec) and rate of perceived exertion (RPE) were recorded differentiating between central backs (CB), midfielders (MF), external players (EX) and forwards (FW). Neuromuscular fatigue were assessed using a jump test. During Soccer-11, players showed significantly higher TD, HSR and VHSR, with low Acc and greater RPE compared with Soccer-7. During Soccer-11, all positions recorded significantly greater TD, distance at HSR and at VHSR than Soccer-7. In terms of playing position, CB, MF and FW achieved significantly higher Peak Speed during Soccer-1, but there was no difference for EX. During Soccer-7 all positions performed significantly higher numbers of Acc. Although the Soccer-7 modality is considered an optimal format for the development of young soccer players, there is a significant difference in match running activity for all playing positions with respect to the Soccer-11 format.

Influence of the Number of Players on the Load of Soccer Players During Transition Games.

The aims of this study were to determine the effect of different compositions in transition games (TGs) on the load of soccer players and to evaluate their performance in physical tests. Using a GPS system, 18 players were monitored during: 3vs2, 2vs1 and 1vs1. Distance covered (DC), DC 18-20.9 km·h-1, 21-23.9 km·h-1,>24 km·h-1, peak speed, accelerations (Acc) and decelerations (Dec)>1.0 m·s-2 and>2.5 m·s-2 and rate of perceived exertion (RPE) were recorded. Before and after each TG, countermovement-jump (CMJ), 15- (S15) and 30 m (S30) speed tests were assessed. TG3vs2 showed greater DC and Dec>1.0 m·s-2 than TG2vs1, and DC, DC 18.0-23.9 km·h-1, Acc>1.0 m·s-2 and Dec>2.5 m·s-2 than TG1vs1 (p<0.01). TG2vs1 achieved higher DC, DC 18.0-23.9 km·h-1, and Acc>2.5 m·s-2 (p<0.01) but lower peak speed (p=0.02) and RPE (p=0.02) than TG1vs1. Post-intervention, TG1vs1 showed lower CMJ and higher S15 (p=0.02), while TG3vs2, showed improvements in CMJ (p<0.01). The three tasks showed large variations for DC>24 km·h-1, Acc>1.0 m·s-2, Dec>1.0 m·s-2 and Dec>2.5 m·s-2. The load of TGs is sensitive to their player composition.

Preliminary Application of Infrared Thermography to Monitoring of Skin Temperature Asymmetries in Professional Padel Players.

The aim of the present study was to evaluate skin temperature (Tsk) asymmetries, using infrared thermography, in professional padel players before (PRE), after (POST) and 10 min after training (POST10), and their relationship with perceptual variables and training characteristics. Thermal images were taken of 10 players before, after and 10 min after a standardized technical training. After training, Tsk of the dominant side was higher than before training in the anterior forearm (30.8 ± 0.4 °C vs. 29.1 ± 1.2 °C, p < 0.01; ES = 1.9), anterior shoulder (31.6 ± 0.6 °C vs. 30.9 ± 0.6 °C, p < 0.05; ES = 1.0) posterior arm (29.5 ± 1.0 °C vs. 28.3 ± 1.2 °C, p < 0.05; ES = 1.0), and posterior forearm (30.8 ± 0.9 °C vs. 29.3 ± 1.6 °C, p < 0.05; ES = 1.1). Likewise, these differences were significant POST10 in the anterior arm, anterior forearm, anterior shoulder, posterior arm and posterior forearm. Comparing the different moments of measurement (PRE, POST and POST10), the temperature was higher POST10 in all the regions analyzed except for the shoulder, abdominals, and lower back. Also, correlations were found between fatigue variation and temperature variation between limbs (Tsk dominance), and no correlation was found except between age and posterior thigh (|r| = 0.69; p < 0.05), and between the racket mass and anterior knee (|r| = 0.81; p < 0.01). In conclusion, infrared thermography allows monitoring of skin asymmetries between limbs in professional padel players, but these asymmetries were not related to overall fatigue variation, overall pain variation, years of experience and training hours.

N-(2-Hydroxyphenyl)-2-Propylpentanamide (HO-AAVPA) Induces Apoptosis and Cell Cycle Arrest in Breast Cancer Cells, Decreasing GPER Expression.

In this work, we performed anti-proliferative assays for the compound N-(2-hydroxyphenyl)-2-propylpentanamide (HO-AAVPA) on breast cancer (BC) cells (MCF-7, SKBR3, and triple-negative BC (TNBC) MDA-MB-231 cells) to explore its pharmacological mechanism regarding the type of cell death associated with G protein-coupled estrogen receptor (GPER) expression. The results show that HO-AAVPA induces cell apoptosis at 5 h or 48 h in either estrogen-dependent (MCF-7) or -independent BC cells (SKBR3 and MDA-MB-231). At 5 h, the apoptosis rate for MCF-7 cells was 68.4% and that for MDA-MB-231 cells was 56.1%; at 48 h, that for SKBR3 was 61.6%, that for MCF-7 cells was 54.9%, and that for MDA-MB-231 (TNBC) was 43.1%. HO-AAVPA increased the S phase in MCF-7 cells and reduced the G2/M phase in MCF-7 and MDA-MB-231 cells. GPER expression decreased more than VPA in the presence of HO-AAVPA. In conclusion, the effects of HO-AAVPA on cell apoptosis could be modulated by epigenetic effects through a decrease in GPER expression.

An update on vitamin D signaling and cancer.

A low vitamin D status is associated with an increased risk of various cancers, such as of colon, breast, prostate and hematological cells. The biologically most active vitamin D metabolite 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) is a high affinity ligand of the transcription factor vitamin D receptor (VDR). 1,25(OH)2D3 induces via VDR changes to the epigenome of healthy and neoplastic cells and in this way influences their transcriptome. Ligand-activated VDR binds to more than 10,000 loci within the human genome and affects the transcription of some 1000 target genes in a large proportion of human tissues and cell types. From the evolutionary perspective, the prime role of vitamin D was probably the control of energy metabolism later shifting to modulate innate and adaptive immunity as well as to regulate calcium and bone homeostasis. Since rapidly growing immune and cancer cells both use the same pathways and genes for controlling their proliferation, differentiation and apoptosis, not surprisingly, vitamin D signaling changes these processes also in neoplastic cells. Thus, anti-cancer effects of vitamin D may derive from managing growth and differentiation in immunity. This review provides an update on the molecular basis of vitamin D signaling, i.e., the effects of 1,25(OH)2D3 on the epigenome and transcriptome, and its relationship to cancer prevention and therapy.