Explore the vast range of titles available.

Chikungunya is a mosquito-borne viral disease that causes fever and severe joint pain for which there is no direct acting drug treatments. Vinyl sulfone SGC-NSP2PRO-1 ( 3 ) was identified as a potent inhibitor of the nsP2 cysteine protease (nsP2pro) that reduced viral titer against infectious isolates of Chikungunya and other alphaviruses. The covalent warhead in 3 captured the active site C478 and inactivated nsP2pro with a k inact / K i ratio of 5950 M –1  s –1 . The vinyl sulfone 3 was inactive across a panel of 23 other cysteine proteases and demonstrated remarkable proteome-wide selectivity by two chemoproteomic methods. A negative control analog SGC-NSP2PRO-1N ( 4 ) retained the isoxazole core and covalent warhead but demonstrated > 100-fold decrease in enzyme inhibition. Both 3 and 4 were stable across a wide range of pH in solution and upon prolonged storage as solids. Vinyl sulfone 3 and its negative control 4 will find utility as high-quality chemical probes to study the role of the nsP2pro in cellular studies of alphaviral replication and virulence.

Activated carbon has been widely used to remove hazardous Cr(VI); however, the impact of Cr2O3 precipitate on gradually declining removal ability as pH increases has received little attention. Herein, to investigate the effect of Cr2O3, SEM-EDX (scanning electron microscope-energy dispersive X-ray analysis) coupling elements mapping of chromium-loaded powdered activated carbon (PAC) revealed that a chromium layer was formed on the PAC exterior after being treated with Cr(VI) at pH 7. XPS (X-ray photoelectron spectroscopy) study confirmed that 69.93% and 39.91% Cr2O3 precipitated on the PAC surface at pH 7 and pH 3, respectively, corresponding to 17.77 mg/g and 20 mg/g removal capacity. Exhausted PAC had a removal efficiency of 92.43% after Cr2O3 being washed by H2SO4 solution, which was much higher than the removal efficiency of 51.27 % after NaOH washing. This further verified that the intrinsically developed Cr2O3 precipitate on PAC under neutral conditions limited the durability of PAC as an adsorbent. Consecutive elution assessments confirmed that adsorption and reduction ability both declined as pH increased. Raman spectroscopy and C 1s spectra of materials demonstrated two distinct Cr(VI) removal mechanisms under pH 3 and pH 7. In conclusion, the exhausted AC after Cr(VI) adsorption can be rejuvenated after the surface coated Cr2O3 is washed by the acid solution, which can expand the longevity of AC and recover Cr(III).

The direct link between a protein’s thermodynamic stability and function influenced the development of mass spectrometry-based methods to characterize the energetics associated with protein folding that enabled the large-scale elucidation of drug protein targets and disease state protein biomarkers. This area of structural biology is undergoing constant development and new applications are emerging. Consequently, the original contributions of this dissertation include (1) the continuation or extension of mass spectrometry and energetic-based strategies for proteome-wide characterization of protein folding stabilities in allergen-containing proteomes to discriminate allergenicity, (2) the hybridization of novel strategies with existing energetic-based approaches utilizing mass spectrometry readout for simpler and efficient characterization of protein folding stabilities and ligand binding, and (3) the development of novel mass spectrometry-based strategies for comprehensive evaluations of the thermodynamics and kinetics of protein folding.First, this dissertation describes comprehensive protein profiling methods to discriminate allergens from non-allergens. As continuation, RNA sequencing (RNA-seq) analysis served as a proxy for protein abundance, and the Stability of Proteins from Rates of Oxidation (SPROX) reported on thermodynamic stability. These techniques characterized the protein expression levels and stability of proteins in the European white birch pollen, Betula pendula (Bp), and German cockroach, Blattella germanica (Bg). The simultaneous comparison of stability and abundance confirmed that Bp and Bg allergens had significantly higher expression levels and higher stabilities compared to non-allergens from the same source. Combining the Bp and Bg results with previous studies for a robust statistical comparison of the abundance and stability of allergens and non-allergens from indoor and outdoor sources confirmed that allergens were significantly more abundant and more stable. The thermodynamic stability of the proteins in Bp was further investigated utilizing a denaturant-dependent Pulse Proteolysis (PP) strategy with thermolysin. Additionally, proteolytic susceptibility was assessed by employing a time-dependent cathepsin S digestion under native conditions. The results confirmed that allergens were significantly less susceptible to thermolysin (more thermodynamically stable) or cathepsin S digestion than the non-allergens in Bp. Additionally, no correlation resulted between the SPROX- and PP-derived thermodynamic stabilities and between the thermodynamic stabilities and proteolytic susceptibilities of selected proteins from Bp. The absence of correlation is attributed to the fundamental differences between techniques—each technique utilizes distinct probes to report on a protein’s thermodynamic stability and/or proteolytic susceptibility. Finally, the PP-derived stability for the major Bp allergen, Bet v 1, correlated with the LiP-derived proteolytic susceptibility and the generation of known T-cell epitopes connecting stability with endosomal processing having allergenic or immunogenic implications. Next, this dissertation reports the first application of the novel one-pot analysis in conjunction with the SPROX methodology for a simplified and efficient evaluation of protein folding and ligand-binding. A hybrid of the one-pot analysis with SPROX utilizing a MALDI readout enabled efficient evaluations of protein stability and ligand binding. The approach generated protein folding stabilities with similar precision to the standard curve-fitting SPROX technique. Furthermore, the one-pot analysis was coupled with the SPROX strategy for a comprehensive deconvolution of Cyclosporine A (CsA) protein targets in yeast. This novel approach identified 3 known CsA protein hits with a 0.04% false positive rate. A cross-validation between techniques (i.e., TPP, CPP, or PP, performed under similar conditions) resulted in false positive rates approaching 0 %. Finally, this dissertation showcases the development of a novel approach utilizing a native or low denaturant-based Reagent-dependent Thiolate-based Reactivity (RTR) assay utilizing mass spectrometry for the evaluation of the thermodynamics and kinetics of protein folding. An RTR strategy titled MTR utilizing a MALDI readout was performed under native conditions to report on the thermodynamics of protein folding. The MTR strategy measured the thermodynamic stability of mutants of the C domain of protein A from Staphylococcus aureus. Additionally, a low denaturant MTR approach reported the thermodynamics and kinetics of protein folding for bovine β-lactoglobulin B (LG-B). A comprehensive application of the native RTR approach was performed on yeast providing thermodynamic stability information for a subset of the proteins.

The development of bifunctional hybrid materials based on natural clays and layered double hydroxide (LDH) and their application on the simultaneous adsorption of Cd(II) and As(V) was investigated in this work. Two different synthesis routes, in situ and assembly, were employed to obtain the hybrid materials. Three types of natural clays, namely bentonite (B), halloysite (H), and sepiolite (S), were used in the study. These clays are characterized by a laminar, tubular, and fibrous structural arrangement, respectively. The physicochemical characterization results indicate that the hybrid materials were formed through interactions between the Al–OH and Si–OH groups present in the natural clays, and the Mg-OH and Al–OH groups present in the LDH for both synthesis routes. However, the “in situ” route yields a more homogenous material because the LDH formation is performed on the natural clay surface. The hybrid materials showed an anion and cation exchange capacity up to 200.7 meq/100 g and an isoelectric point near 7. The arrangement of natural clay has no impact on the properties of hybrid material but influences the adsorption capacity. The adsorption of Cd(II) onto hybrid materials was enhanced in comparison with natural clays, obtaining adsorption capacities of 80, 74, 65, and 30 mg/g for 15:1 (LDH:H) INSITU , 1:1 (LDH:S) INSITU , 1:1 (LDH:B) INSITU , and 1:1 (LDH:H) INSITU , respectively. The adsorption capacities of hybrid materials to adsorb As(V) were between 20 and 60 μg/g. The 15:1 (LDH:H) INSITU sample showed the best adsorption capacity being ten folds greater than halloysite and LDH. In all cases, the hybrid materials showed a synergistic effect for Cd(II) and As(V) adsorption. The adsorption study of Cd(II) onto hybrid materials showed that the primary adsorption mechanism is cation exchange between the interlayer cations in natural clay and Cd(II) in the aqueous solution. The adsorption of As(V) showed that the adsorption mechanism is attributed to anion exchange between CO 2 3− in the interlayer space of LDH and H 2 ASO 4 − in the solution. The simultaneous adsorption of As (V) and Cd (II) shows that, during the As(V) adsorption, there is no competition by the adsorption sites. Still, the adsorption capacity towards Cd(II) was enhanced 1.2-folds. This study ultimately revealed that the arrangement of clay has a significant influence on the adsorption capacity of the hybrid material. This can be attributed to the similar morphology between the hybrid material and natural clays, as well as the important diffusion effects observed in the system.

Titanium oxide (TiO2) is of great interest in solar cell manufacturing, hydrogen production, and organic compound photodegradation. The synthesis variables and methodology affect the morphology, texture, crystalline structure, and phase mixtures of TiO2, which, in turn, affect the optical and catalytic properties of TiO2. In this work, the effect of acetic acid as a catalyst and chelating agent on the morphology, texture, crystal structure, optical properties, and photocatalytic activity of TiO2 samples obtained using the sol–gel method with sodium dodecyl sulfate (SDS) as a template was investigated. The results indicated that acetic acid not only catalyzes the hydrolysis of the TiO2 precursor but also acts as a chelating agent, causing a decrease in crystallite size from 18.643 nm (T7 sample, pH = 6.8, without addition of acetic acid) to 16.536 nm (T2 sample, pH = 2). At pH 2 and 3, only the anatase phase was formed (T2 and T3 samples), whereas at pH 5 and 6.8, in addition to the anatase phase, the brookite phase (11.4% and 15.61% for samples T5 and T7, respectively) was formed. The band-gap value of TiO2 decreased with decreasing pH during synthesis. Although the T2 sample had the highest specific surface area and pore volume (232.02 m2g−1 and 0.46 gcm−3, respectively), the T3 sample had better efficiency in methylene blue dye photodegradation because its bird-nest-like morphology improved photon absorption, promoting better photocatalytic performance.

Current challenges in froth flotation are the presence of complex gangues and the use of low-quality waters, such as seawater. In this scenario, the recovery of molybdenum minerals is difficult, mainly due to the hydrophobic faces’ physicochemical changes. In the present study, the natural floatability of pure molybdenite was analyzed by using microflotation assays, and hydrophobicity was measured by performing contact-angle measurements. The impact of two clays, kaolin (non-swelling) and Na-montmorillonite (swelling), was studied. The behavior in freshwater and seawater at pH 8 was compared, considering the current condition of the Cu/Mo mining industries, which use seawater in their operations. The presence of clays lowered the natural floatability of molybdenite precisely because they adhere to the surface and reduce its contact angle. However, the intensity with which they cause this phenomenon depends on the type of water and clay. Kaolin strongly adheres to the valuable mineral in both freshwater and seawater. For its part, Na-montmorillonite does it with greater intensity in a saline medium, but in freshwater, a high concentration of phyllosilicate is required to reduce the hydrophobicity of molybdenite. The clays’ adherence was validated by scanning electron microscopy (SEM) analysis.

is a growing health concern as the leading causal agent of systemic candidiasis, a life-threatening fungal infection with a mortality rate of ~40% despite best available therapy. Yck2, a fungal casein kinase 1 (CK1) family member, is the cellular target of inhibitors YK-I-02 (YK) and MN-I-157 (MN). Here, multiplexed inhibitor beads paired with mass spectrometry (MIB/MS) employing ATP-competitive kinase inhibitors were used to define the selectivity of these Yck2 inhibitors across the global proteome. The MIB matrix captured 89% of the known and predicted protein kinases present in cell lysate. In MIB/MS competition assays, YK and MN demonstrated exquisite selectivity across the fungal kinome with target engagement of only three CK1 homologs (Yck2, Yck22, and Hrr25) and a homolog of human p38α (Hog1). Additional chemoproteomics using a custom MN-kinobead identified only one additional protein, confirming its remarkable fungal proteome-wide selectivity. To identify new Yck2 inhibitors with selectivity over Hog1, thirteen human CK1 kinase inhibitors were profiled for fungal kinase-binding activity using MIB/MS competition assays and in-cell NanoBRET target engagement assays. A new chemotype of family-selective Yck2 inhibitors with antifungal activity was identified. Together, these findings expand the application of MIB/MS proteomic profiling for non-human kinomes and demonstrate its utility in the discovery and development of selective inhibitors of fungal kinases with potential antimicrobial activity.

The authors assessed the cross-national replicability of methods previously used to study medical encounters in the United States by adapting them to Mexico. The main research questions focused on information-giving, gender and social class differences in communication, and attention to socioemotional concerns in primary care encounters. Sixty-two primary-care encounters were audiotaped. Questionnaires were translated into Spanish, then translated back into English. Coding and transcription techniques were taught to Spanish-speaking researchers. Measures of communication were treated as dependent variables and were related by nonparametric statistical analyses to characteristics of physicians, patients, and clinical settings. Doctors in Mexico spent an average of 2.1 minutes (±1.7 standard deviation [SD]), or 16.7% (±10.7 SD) of total interaction time, in information-giving. Mexican doctors asked an average of 27.3 questions per encounter (±18.0 SD), whereas patients asked an average of 1.5 questions (±2.0 SD). Substantial interphysician variability was observed in total time of interaction (Kruskal-Wallis analysis of variance, chi-square = 27.2, P = 0.000), physician time in information-giving (chi-square = 16.4, P = 0.022), and physician questions (chi-square = 36.7, P = 0.000). Patient characteristics associated with physician information-giving included male gender (chi-square = 4.1, P = 0.04) and age (Kendall's tau-b = .17, P = 0.05) but not education (tau-b = .08, P = 0.41). Information-giving in public clinics did not differ from that in private practices (chi-square = 0.0, P = 0.91). A bootstrap approach to multiple nonlinear regression permitted additional analysis of physicians', patients', and situational characteristics in explaining measures of patient-doctor communication; this analysis further demonstrated the importance of interphysician variability in communicative behavior. Previous methods for studying patient-doctor communication can be adapted and replicated in a non-English-speaking society. With certain exceptions, findings from Mexico were similar to those obtained in the United States.

Hypomorphic Glucose 6-P dehydrogenase (G6PD) alleles, which cause G6PD deficiency, affect around one in twenty people worldwide. The high incidence of G6PD deficiency may reflect an evolutionary adaptation to the widespread prevalence of malaria, as G6PD-deficient red blood cells (RBCs) are hostile to the malaria parasites that infect humans. Although medical interest in this enzyme deficiency has been mainly focused on RBCs, more recent evidence suggests that there are broader implications for G6PD deficiency in health, including in skeletal muscle diseases. G6PD catalyzes the rate-limiting step in the pentose phosphate pathway (PPP), which provides the precursors of nucleotide synthesis for DNA replication as well as reduced nicotinamide adenine dinucleotide phosphate (NADPH). NADPH is involved in the detoxification of cellular reactive oxygen species (ROS) and de novo lipid synthesis. An association between increased PPP activity and the stimulation of cell growth has been reported in different tissues including the skeletal muscle, liver, and kidney. PPP activity is increased in skeletal muscle during embryogenesis, denervation, ischemia, mechanical overload, the injection of myonecrotic agents, and physical exercise. In fact, the highest relative increase in the activity of skeletal muscle enzymes after one bout of exhaustive exercise is that of G6PD, suggesting that the activation of the PPP occurs in skeletal muscle to provide substrates for muscle repair. The age-associated loss in muscle mass and strength leads to a decrease in G6PD activity and protein content in skeletal muscle. G6PD overexpression in Drosophila Melanogaster and mice protects against metabolic stress, oxidative damage, and age-associated functional decline, and results in an extended median lifespan. This review discusses whether the well-known positive effects of exercise training in skeletal muscle are mediated through an increase in G6PD.

Spain is one of the European countries most affected by the COVID-19 pandemic. Serological surveys are a valuable tool to assess the extent of the epidemic, given the existence of asymptomatic cases and little access to diagnostic tests. This nationwide population-based study aims to estimate the seroprevalence of SARS-CoV-2 infection in Spain at national and regional level. 35 883 households were selected from municipal rolls using two-stage random sampling stratified by province and municipality size, with all residents invited to participate. From April 27 to May 11, 2020, 61 075 participants (75·1% of all contacted individuals within selected households) answered a questionnaire on history of symptoms compatible with COVID-19 and risk factors, received a point-of-care antibody test, and, if agreed, donated a blood sample for additional testing with a chemiluminescent microparticle immunoassay. Prevalences of IgG antibodies were adjusted using sampling weights and post-stratification to allow for differences in non-response rates based on age group, sex, and census-tract income. Using results for both tests, we calculated a seroprevalence range maximising either specificity (positive for both tests) or sensitivity (positive for either test). Seroprevalence was 5·0% (95% CI 4·7–5·4) by the point-of-care test and 4·6% (4·3–5·0) by immunoassay, with a specificity–sensitivity range of 3·7% (3·3–4·0; both tests positive) to 6·2% (5·8–6·6; either test positive), with no differences by sex and lower seroprevalence in children younger than 10 years (<3·1% by the point-of-care test). There was substantial geographical variability, with higher prevalence around Madrid (>10%) and lower in coastal areas (<3%). Seroprevalence among 195 participants with positive PCR more than 14 days before the study visit ranged from 87·6% (81·1–92·1; both tests positive) to 91·8% (86·3–95·3; either test positive). In 7273 individuals with anosmia or at least three symptoms, seroprevalence ranged from 15·3% (13·8–16·8) to 19·3% (17·7–21·0). Around a third of seropositive participants were asymptomatic, ranging from 21·9% (19·1–24·9) to 35·8% (33·1–38·5). Only 19·5% (16·3–23·2) of symptomatic participants who were seropositive by both the point-of-care test and immunoassay reported a previous PCR test. The majority of the Spanish population is seronegative to SARS-CoV-2 infection, even in hotspot areas. Most PCR-confirmed cases have detectable antibodies, but a substantial proportion of people with symptoms compatible with COVID-19 did not have a PCR test and at least a third of infections determined by serology were asymptomatic. These results emphasise the need for maintaining public health measures to avoid a new epidemic wave. Spanish Ministry of Health, Institute of Health Carlos III, and Spanish National Health System.