Hyperosmotic priming of arabidopsis seedlings establishes a long-term somatic memory accompanied by specific changes of the epigenome

<p>Background: In arid and semi-arid environments, drought and soil salinity usually occur at the beginning and end of a plant's life cycle, offering a natural opportunity for the priming of young plants to enhance stress tolerance in mature plants. Chromatin marks, such as histone modifications, provide a potential molecular mechanism for priming plants to environmental stresses, but whether transient exposure of seedlings to hyperosmotic stress leads to chromatin changes that are maintained throughout vegetative growth remains unclear.</p> <p>Results: We have established an effective protocol for hyperosmotic priming in the model plant Arabidopsis, which includes a transient mild salt treatment of seedlings followed by an extensive period of growth in control conditions. Primed plants are identical to non-primed plants in growth and development, yet they display reduced salt uptake and enhanced drought tolerance after a second stress exposure. ChIP-seq analysis of four histone modifications revealed that the priming treatment altered the epigenomic landscape; the changes were small but they were specific for the treated tissue, varied in number and direction depending on the modification, and preferentially targeted transcription factors. Notably, priming leads to shortening and fractionation of H3K27me3 islands. This effect fades over time, but is still apparent after a ten day growth period in control conditions. Several genes with priming-induced differences in H3K27me3 showed altered transcriptional responsiveness to the second stress treatment.</p> <p>Conclusion: Experience of transient hyperosmotic stress by young plants is stored in a long-term somatic memory comprising differences of chromatin status, transcriptional responsiveness and whole plant physiology.</p&gt

Tunneling spectroscopy studies of aluminum oxide tunnel barrier layers

We report scanning tunneling microscopy and ballistic electron emission microscopy studies of the electronic states of the uncovered and chemisorbed-oxygen covered surface of AlOx tunnel barrier layers. These states change when chemisorbed oxygen ions are moved into the oxide by either flood gun electron bombardment or by thermal annealing. The former, if sufficiently energetic, results in locally well defined conduction band onsets at ~1 V, while the latter results in a progressively higher local conduction band onset, exceeding 2.3 V for 500 and 600 C thermal anneals

Seismic vulnerability of Santa Maria Novella Basilica in Florence

This paper presents the evaluation of the seismic vulnerability of Santa Maria Novella Basilica in Florence. Santa Maria Novella is one of the most important historical churches in Italy and, for this reason, different studies on the structural behavior of this monument were conducted during the last decades. Particularly, this work is focused on the dynamic behavior of the church. Mechanical properties of masonries were determined through "in situ" and laboratory tests, according to the National Italian Code (Norme Tecniche per le Costruzioni, 2018). An eigenvalue analysis on a finite element model of the Basilica was performed to obtain the fundamental vibration mode shapes.Finally, to evaluate the seismic risk index in terms of ratio between the minimum peak ground acceleration which leads to the first collapse of a structural element and the design peak ground acceleration, a response spectrum analysis was carried out to evaluate the stress fields in both columns and walls

Stress Relaxation Behavior of Additively Manufactured Polylactic Acid (PLA)

In this work, the stress relaxation behavior of 3D printed PLA was experimentally investigated and analytically modeled. First, a quasi-static tensile characterization of additively manufactured samples was conducted by considering the effect of printing parameters like the material infill orientation and the outer wall presence. The effect of two thermal conditioning treatments on the material tensile properties was also investigated. Successively, stress relaxation tests were conducted, on both treated and unconditioned specimens, undergoing three different strains levels. Analytical predictive models of the viscous behavior of additive manufactured material were compared, highlighting and discussing the effects of considered printing parameters

Pre-exposure prophylaxis with hydroxychloroquine does not prevent covid-19 nor virus related venous thromboembolism

Different and several public health strategies have been planned to reduce transmission of pandemic due to SARS-CoV-2 since it started. None drugs have been confirmed as able to prevent viral transmission. Hydroxychloroquine with its immunomodulatory properties has been proposed as potential anti-viral drug in particular for prevention once viral exposure has been happen or in first phases of infection. Furthermore, in several immunological systemic disease hydroxychloroquine was able to reduce the number of thrombotic complications. So, because COVID-19 was associated to immunological imbalance and to thrombotic complications, we retrospectively analyzed the rate of infection in those patients being under treatment with this drug during COVID-19 epidemic outbreak from 8 March until 28 April in particular comparing those with pre-exposure to this treatment and those that were not taking this medication before SARS-CoV-2 viral infections

Interleukin-6 and granulocyte macrophage-CSF in the cerebrospinal fluid from HIV infected subjects with involvement of the central nervous system.

We detected the cytokines interleukin-6 (IL-6) and granulocyte macrophage-CSF (GM-CSF) by ELISA in the CSF and serum of 30 HIV-infected patients classified as AIDS dementia complex (ADC), and 20 subjects with other neurological diseases (OND). We have found a high incidence of detectable IL-6 and GM-CSF in the CSF of ADC patients compared with OND patients. No statistical differences were observed between both groups for serum IL-6 and GM-CSF levels. These results suggest an intrathecal synthesis of these cytokines and a possible involvement in the pathogenesis of ADC

Development and validation of a clinical risk score to predict the risk of SARS-CoV-2 infection from administrative data: A population-based cohort study from Italy

Background The novel coronavirus (SARS-CoV-2) pandemic spread rapidly worldwide increasing exponentially in Italy. To date, there is lack of studies describing clinical characteristics of the people at high risk of infection. Hence, we aimed (i) to identify clinical predictors of SARSCoV-2 infection risk, (ii) to develop and validate a score predicting SARS-CoV-2 infection risk, and (iii) to compare it with unspecific scores. Methods Retrospective case-control study using administrative health-related database was carried out in Southern Italy (Campania region) among beneficiaries of Regional Health Service aged over than 30 years. For each person with SARS-CoV-2 confirmed infection (case), up to five controls were randomly matched for gender, age and municipality of residence. Odds ratios and 90% confidence intervals for associations between candidate predictors and risk of infection were estimated by means of conditional logistic regression. SARS-CoV-2 Infection Score (SIS) was developed by generating a total aggregate score obtained from assignment of a weight at each selected covariate using coefficients estimated from the model. Finally, the score was categorized by assigning increasing values from 1 to 4. Discriminant power was used to compare SIS performance with that of other comorbidity scores. Results Subjects suffering from diabetes, anaemias, Parkinson’s disease, mental disorders, cardiovascular and inflammatory bowel and kidney diseases showed increased risk of SARSCoV-2 infection. Similar estimates were recorded for men and women and younger and older than 65 years. Fifteen conditions significantly contributed to the SIS. As SIS value increases, risk progressively increases, being odds of SARS-CoV-2 infection among people with the highest SIS value (SIS = 4) 1.74 times higher than those unaffected by any SIS contributing conditions (SIS = 1). Conclusion Conditions and diseases making people more vulnerable to SARS-CoV-2 infection were identified by the current study. Our results support decision-makers in identifying high-risk people and adopting of preventive measures to minimize the spread of further epidemic waves

PEGylation Promotes Hemoglobin Tetramer Dissociation

Hemoglobin conjugated with poly(ethylene glycol) (PEG) acts as an oxygen carrier free in plasma, substituting red blood cells in supplementing oxygen in hypo-oxygenation pathologies. Given the complexity of oxygen delivery controls, subtle structural and functional differences in PEGylated hemoglobins might be associated with distinct physiological responses and, potentially, adverse effects. We have compared hemoglobin PEGylated under anaerobic conditions, called PEG-Hb(deoxy), with hemoglobin PEGylated under aerobic conditions, called PEG-Hb(oxy), a product that mimics Hemospan, produced by Sangart, Inc. SDS PAGE and MALDI-TOF analyses demonstrated that PEG conjugation yields products characterized by a broad distribution of PEG/hemoglobin ratios. The elution profiles in size-exclusion chromatography indicate that both products exhibit a more homogeneous distribution of molecular weight/hydrodynamic volume under deoxy conditions and at higher concentrations. PEG-Hb(oxy) shows high oxygen affinity, low modulation of allosteric effectors, almost no cooperativity, a fast and monophasic CO binding, and a limited dependence of functional properties on concentration, whereas PEG-Hb(deoxy) exhibits oxygen binding curves that significantly depend on protein concentration, and a slow CO binding, similar to native hemoglobin. PEGylated CO-hemoglobins, probed by flash photolysis, exhibited a lower amplitude for the geminate rebinding phase with respect to native hemoglobin and a negligible T state bimolecular CO rebinding phase. These findings are explained by an increased dissociation of PEGylated hemoglobins into dimers and perturbed T and R states with decreased quaternary transition rates. These features are more pronounced for PEG-Hb(oxy) than PEG-Hb(deoxy). The detected heterogeneity might be a source of adverse effects when PEGylated Hbs are used as blood substitutes

Breastmilk cell and fat contents respond similarly to removal of breastmilk by the infant

Large inter- and intra-individual variations exist in breastmilk composition, yet factors associated with these variations in the short-term are not well understood. In this study, the effects of breastfeeding on breastmilk cellular and biochemical content were examined. Serial breastmilk samples (~5 mL) were collected from both breasts of breastfeeding women before and immediately after the first morning breastfeed, and then at 30-minute intervals for up to 3 hours post-feed on 2–4 mornings per participant. The infant fed from one breast only at each feed. Effects of pump versus hand expression for samples were evaluated. A consistent response pattern of breastmilk cell and fat contents to breastmilk removal was observed. Maximum fat and cell levels were obtained 30 minutes post-feed (P0.01), with up to 8-fold increase in fat and 12-fold increase in cell content compared to the pre-feed values, and then they gradually decreased. Breastmilk cell viability and protein concentration did not change with feeding (P>0.05), although large intra-individual variability was noted for protein. Expression mode for samples did not influence breastmilk composition (P>0.05). It is concluded that breastmilk fat content, and thus breast fullness, is closely associated with breastmilk cell content. This will now form the basis for standardization of sampling protocols in lactation studies and investigation of the mechanisms of milk synthesis and cell movement into breastmilk. Moreover, these findings generate new avenues for clinical interventions exploring growth and survival benefits conferred to preterm infants by providing the highest in fat and cells milk obtained at 30 min post-expression

The dissociation of carbon monoxide from hemoglobin intermediates

To investigate the mechanism of allosteric switching in human hemoglobin, we have studied the dissociation of the ligand (CO) from several intermediate ligation states by a stopped-flow kinetic technique that utilizes competitive binding of CO by microperoxidase. The hemoglobin species investigated include Hb(CO)4, the diliganded symmetrical species (\u3b1 \u3b2-CO)2 and (\u3b1-CO \u3b2)2 and the di- and monoliganded asymmetrical species (\u3b1-CO \u3b2-CO)(\u3b1 \u3b2), (\u3b1-CO \u3b2)(\u3b1 \u3b2-CO), (\u3b1 \u3b2-CO)(\u3b1 \u3b2), and (\u3b1-CO \u3b2)(\u3b1 \u3b2). They were obtained by rapid reduction with dithionite of the corresponding valence intermediates that in turn were obtained by chromatography or by hybridization. The nature and concentration of the intermediates were determined by isoelectric focusing at -25\ub0C. The study was performed at varying hemoglobin concentrations (0.1, 0.02, and 0.001 mM [heme]), pH (6.0, 7.0, 8.0), with and without inositol hexaphosphate. The results indicate that: (a) hemoglobin concentration in the 0.1-0.02 mM range does not significantly affect the kinetic rates; (b) the \u3b1 chains dissociate CO faster than the \u3b2 chains; (c) the symmetrical diliganded intermediates show cooperativity with respect to ligand dissociation that disappears in the presence of inositol hexaphosphate; (d) the monoliganded intermediates dissociate CO faster than the diliganded intermediates; (e) the asymmetrical diliganded intermediates are functionally different from the symmetrical species