Search Results (53)

Assessing the propensity of ingredients to induce skin sensitization through in vitro testing is crucial for worker and consumer safety. This is particularly important for novel and high-performance ingredients with complex structures, such as rheology-modifying polymers, which are extensively used in cosmetics, pharmaceuticals, and detergents. The Sens-Is assay has proven effective in distinguishing skin sensitizers from non-sensitizers for difficult-to-test ingredients when integrated into a multi-method in vitro approach. Therefore, the primary goal of this research was to explore whether the Sens-Is in vitro assay is suitable to evaluate rheology-modifying polymers. Fifteen structurally diverse rheology-modifying polymers, including natural polymers obtained by extraction, chemical synthesis, or biotechnology, spanning varying physical forms and concentrations, were evaluated. The results showed that most polymers were non-sensitizing, consistent with available in vivo data. Although polymer macromolecules generally exhibit limited skin sensitization potential due to their surface confinement, the Sens-Is assay permitted the detection of weak signals from secondary components or possible byproducts in specific cases. This work confirms Sens-Is as a useful tool in an overall approach to assessing the skin sensitization liability of polymers under development, but careful solvent selection is crucial to ensure accurate results and prevent potential overexposure due to polymer retention on the epidermal surface. Full article

Background/Objectives: Postoperative atrial fibrillation (POAF) is the most frequent arrhythmic complication following cardiac surgery and is associated with increased morbidity and prolonged recovery. This study aimed to evaluate the impact of an enhanced recovery after surgery (ERAS) program on the incidence of POAF and broader perioperative outcomes. Methods: In this monocentric, observational cohort study, we compared a retrospective pre-ERAS cohort (n = 162) with a prospective ERAS cohort (n = 321). The primary outcome was the incidence of POAF, assessed using two definitions: (1) the American Association for Thoracic Surgery (AATS) 2014 clinical definition, identifying POAF as atrial fibrillation requiring treatment; and (2) the European Society of Cardiology (ESC) 2024 definition, describing new-onset atrial fibrillation occurring immediately after surgery. Secondary outcomes included compliance with POAF prophylaxis measures, length of hospital stay, and the occurrence of postoperative complications. Statistical analyses included propensity score matching and multivariate logistic regression to identify independent predictors of POAF. Results: ERAS implementation was associated with a significant reduction in POAF incidence across both definitions. According to the AATS 2014 definition, POAF occurred in 20% of ERAS patients vs. 39% in the pre-ERAS group (p = 0.001), and 23% vs. 39% in the matched cohort (p = 0.004). Using the ESC 2024 definition, POAF was observed in 21% vs. 37% (p = 0.001) in unmatched and 20% vs. 36% (p = 0.005) in matched populations. Compliance with POAF prophylaxis improved markedly in the ERAS group (70% vs. 21%, p = 0.001). ERAS patients also experienced shorter hospital stays and fewer postoperative complications (26% vs. 38% in the matched cohort, p = 0.033). Conclusions: The implementation of a structured ERAS protocol significantly reduced POAF incidence, improved compliance with preventive strategies, and enhanced key aspects of postoperative recovery. Full article

Disaccharide trehalose has been proven in many cases to be particularly effective in preserving the functional and structural integrity of biological macromolecules. In this work, we studied its effect on the electron transfer reactions that occur in the chromatophores of the photosynthetic bacterium Cereibacter sphaeroides. In the presence of a high concentration of trehalose, following the activation of the photochemistry by flashes of light, a slowdown of the electrogenic reactions related to the activity of the photosynthetic reaction center and cytochtome (cyt) bc₁ complexes is observable. The kinetics of the third phase of the electrochromic carotenoid shift, due to electrogenic events linked to the reduction in cyt b_H heme via the low-potential branch of the cyt bc₁ complex and its oxidation by quinone molecule on the Q_i site, is about four times slower in the presence of trehalose. In parallel, the reduction in oxidized cyt (c₁ + c₂) and high-potential cyt b_H are strongly slowed down, suggesting that the disaccharide interferes with the electron transfer reactions of the high-potential branch of the bc₁ complex. A slowing effect of trehalose on the kinetics of the electrogenic protonation of the secondary quinone acceptor Q_B in the reaction center complex, measured by direct electrometrical methods, was also found, but was much less pronounced. The direct detection of carbohydrate content indicates that trehalose, at high concentrations, permeates the membrane of chromatophores. The possible mechanisms underlying the observed effect of trehalose on the electron/proton transfer process are discussed in terms of trehalose’s propensity to form strong hydrogen bonds with its surroundings. Full article

Alpha-synuclein (ASyn) is a protein that is known to play a critical role in Parkinson’s disease (PD) due to its propensity for misfolding and aggregation. Furthermore, this process leads to oxidative stress and the formation of free radicals that cause neuronal damage. In this study, we have utilized a biomimetic approach to design new peptides derived from marine natural resources. The peptides were designed using a peptide scrambling approach where antioxidant moieties were combined with fibrillary inhibition motifs in order to design peptides that would have a dual targeting effect on ASyn misfolding. Of the 20 designed peptides, 12 were selected for examining binding interactions through molecular docking and molecular dynamics approaches, which revealed that the peptides were binding to the pre-NAC and NAC (non-amyloid component) domain residues such as Tyr39, Asn65, Gly86, and Ala85, among others. Because ASyn filaments derived from Lewy body dementia (LBD) have a different secondary structure compared to pathogenic ASyn fibrils, both forms were tested computationally. Five of those peptides were utilized for laboratory validation based on those results. The binding interactions with fibrils were confirmed using surface plasmon resonance studies, where EQALMPWIWYWKDPNGS, PYYYWKDPNGS, and PYYYWKELAQM showed higher binding. Secondary structural analyses revealed their ability to induce conformational changes in ASyn fibrils. Additionally, PYYYWKDPNGS and PYYYWKELAQM also demonstrated antioxidant properties. This study provides insight into the binding interactions of varying forms of ASyn implicated in PD. The peptides may be further investigated for mitigating fibrillation at the cellular level and may have the potential to target ASyn. Full article

To explore the impact mechanisms of China’s low-carbon pilot policies on urban carbon emissions, this paper employs the propensity-score-matched difference-in-differences (PSM-DID) methodology, in conjunction with a dynamic marginal effect analysis, to examine the mechanisms through which China’s low-carbon pilot policies, initiated in three phases at disparate points in time, influence urban carbon emissions. The analysis is based on urban panel data from 2009 to 2020. The case demonstrates that the low-carbon pilot policies have had a considerable positive impact on the reduction of urban carbon emissions. Improving the efficiency of energy use and promoting the transformation of the industrial structure towards modern services are pivotal to curbing the intensity of carbon emissions. While the impact on the secondary industry is not statistically significant, these policies do have a significant impact on the restructuring of the tertiary industry. Increasing the amount of carbon sink in urban green spaces likewise has no discernible impact on lowering carbon emissions. Consequently, it is recommended that low-carbon technological innovation be further strengthened, including industrial upgrading, energy consumption control, and renewable energy development. Through these strategies, not only can carbon emissions be effectively reduced, they can thereby facilitate the creation of an environmentally friendly and resilient low-carbon city. Full article

Since the emergence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the viral spike protein (S) has become a target to describe appropriate epitopes for vaccine development and to carry out epidemiological surveillance, especially regarding the variants of concern (VOCs). This study aimed to evaluate the influence of mutations on physicochemical properties of S proteins from prototypical SARS-CoV-2 VOCs detected in Amazonian countries. Using multiple computational tools, seven VOCs (B.1.1.7/P.1/B.1.617.2/BA.1/BA.2/BA.4/BA.5) were identified and compared to the ancestral lineage of the virus (B). In all variants, most amino acids were nonpolar; among the polar amino acids, B.1.617.2/BA.1/BA.2/BA.4/BA.5 presented a slightly higher proportion of basic residues and a lower proportion of neutral residues. Unlike B.1.1.7/P.1/B.1.617.2, BA.1/BA.2 had a greater content of secondary structures, such as α-helices and β-sheets. Regarding post-translational modifications, BA.2/BA.4/BA.5 presented fewer glycosylations and phosphorylations. Finally, a more prominent antigenic propensity in the N-terminal domain of BA.2/BA.4/BA.5 and in the receptor-binding domain of B.1.617.2/BA.4/BA.5 was observed. In conclusion, the omicron variants of SARS-CoV-2 presented greater sequence variability in S proteins compared to the other VOCs, influencing structural aspects that can potentially modulate its interaction with cellular receptors and recognition by the immune system. Full article

A high alkaline pH was previously demonstrated to enhance the extraction yield of brewer’s spent grains (BSG) proteins. The effects of extraction pH beyond the extraction yield, however, has not been investigated before. The present work examined the effects of extraction pH (pH 8–12) on BSG proteins’ (1) amino acid compositions, (2) secondary structures, (3) thermal stability, and (4) functionalities (i.e., water/oil holding capacity, emulsifying, and foaming properties). The ideal extraction temperature (60 °C) and BSG-to-solvent ratio (1:20 w/v) for maximizing the extraction yield were first determined to set the conditions for the pH effect study. The results showed that a higher extraction pH led to more balanced compositions between hydrophilic and hydrophobic amino acids and higher proportions of random coils structures indicating increased protein unfolding. This led to superior emulsifying properties of the extracted proteins with more than twofold improvement between pH 8 and a pH larger than 10. The extraction pH, nevertheless, had minimal impact on the water/oil holding capacity, foaming properties, and thermal denaturation propensity of the proteins. The present work demonstrated that a high alkaline pH at pH 11–12 was indeed ideal for both maximizing the extraction yield (37–46 wt.%) and proteins’ functionalities. Full article

Background/Objectives: Hip fractures exert a substantial burden on hospital systems. Within Scotland 20% of the population resides rurally, warranting investigation of how this impacts prompt access to surgical care. This study aims to determine whether indirect hospital admission via hospital transfer affects the likelihood of surgical management within 36 h for hip fracture patients. Methods: A retrospective cohort study was performed. This used Scottish Hip Fracture Audit data including patients aged ≥50 split into two propensity matched groups based on their transfer status. Descriptive analysis compared patient characteristics. Regression assessed achieving surgery within 36 h of admission in the unmatched and matched cohorts. Secondary outcomes included time to surgery, mortality, mobilization, returning to residence and length of stay. A sensitivity analysis was undertaken to assess for residual confounding effects. Results: The unmatched analysis included 20,132 patients. Transfer patients were younger (p = 0.007) and less-comorbid (p < 0.001). In the matched population, 711 (63.6%) transfer patients had surgery with 36 h of presentation to hospital, compared to 852 (75.3%) non-transfer patients. Transfer patients had 43% reduced odds of timely surgery (OR (95% CI) 0.57 (0.48 to 0.69); p < 0.001). No disparities emerged in mortality, mobilisation or returning to residence., Transfer patients experienced a significant increase in length of stay in hospital (median (IQR) 16 (8 to 33) vs. 13 (8 to 30); p = 0.024). Conclusions: Hospital transfer is associated with significantly reduced odds of timely surgery, a longer time to surgery and longer length of stay. Development of structured network pathways that minimize delay to transfer are required to potentially optimize outcomes and reduce associated cost. Full article

Lung surfactant is a mixture of lipids and proteins and is essential for air breathing in mammals. The hydrophobic surfactant proteins B and C (SP-B and SP-C) assist in reducing surface tension in the lung alveoli by organizing the surfactant lipids. SP-B deficiency is life-threatening, and a lack of SP-C can lead to progressive interstitial lung disease. B-YL (41 amino acids) is a highly surface-active, sulfur-free peptide mimic of SP-B (79 amino acids) in which the four cysteine residues are replaced by tyrosine. Mammalian SP-C (35 amino acids) contains two cysteine-linked palmitoyl groups at positions 5 and 6 in the N-terminal region that override the β-sheet propensities of the native sequence. Canine SP-C (34 amino acids) is exceptional because it has only one palmitoylated cysteine residue at position 4 and a phenylalanine at position 5. We developed canine SP-C constructs in which the palmitoylated cysteine residue at position 4 is replaced by phenylalanine (SP-Cff) or serine (SP-Csf) and a glutamic acid-lysine ion-lock was placed at sequence positions 20–24 of the hydrophobic helical domain to enhance its alpha helical propensity. AI modeling, molecular dynamics, circular dichroism spectroscopy, Fourier Transform InfraRed spectroscopy, and electron spin resonance studies showed that the secondary structure of canine SP-Cff ion-lock peptide was like that of native SP-C, suggesting that substitution of phenylalanine for cysteine has no apparent effect on the secondary structure of the peptide. Captive bubble surfactometry demonstrated higher surface activity for canine SP-Cff ion-lock peptide in combination with B-YL in surfactant lipids than with canine SP-Csf ion-lock peptide. These studies demonstrate the potential of canine SP-Cff ion-lock peptide to enhance the functionality of the SP-B peptide mimic B-YL in synthetic surfactant lipids. Full article

Intrinsically disordered regions (IDRs) of transcription factors play an important biological role in liquid condensate formation and gene regulation. It is thus desirable to investigate the druggability of IDRs and how small-molecule binders can alter their conformational stability. For the androgen receptor (AR), certain covalent ligands induce important changes, such as the neutralization of the condensate. To understand the specificity of ligand–IDR interaction and potential implications for the mechanism of neutralizing liquid–liquid phase separation (LLPS), we modeled and performed computer simulations of ligand-bound peptide segments obtained from the human AR. We analyzed how different covalent ligands affect local secondary structure, protein contact map, and protein–ligand contacts for these protein systems. We find that effective neutralizers make specific interactions (such as those between cyanopyrazole and tryptophan) that alter the helical propensity of the peptide segments. These findings on the mechanism of action can be useful for designing molecules that influence IDR structure and condensate of the AR in the future. Full article

The kafirin derived from Jin Nuo 3 sorghum underwent a high-hydrostatic-pressure (HHP) treatment of 100, 300, and 600 MPa for 10 min to investigate alterations in its physicochemical attributes. The findings exhibited a reduction in protein solubility, declining from 83% to 62%, consequent to the application of the HHP treatment. However, this treatment did not lead to subunit-specific aggregation. The absorption intensity of UV light diminished, and the peak fluorescence absorption wavelength exhibited a shift from 342 nm to 344 nm, indicating an increased polarity within the amino acid microenvironment. In an aqueous solution, the specific surface area expanded from 294.2 m²/kg to 304.5 m²/kg, while the average particle-size value in a 70% ethanol solution rose to 26.3 nm. Conversely, the zeta-potential value decreased from 3.4 mV to 1.3 mV, suggesting a propensity for aggregation in ethanol solutions. A notable rise in the intermolecular β-sheet content to 21.06% was observed, along with a shift in the peak denaturation temperature from 76.33 °C to 86.33 °C. Additionally, the content of disulfide bonds increased to 14.5 μmol/g. Collectively, the application of the HHP treatment not only enhanced the thermal stability but also induced a more ordered secondary structure within the kafirin. Full article

Mayaro (MAYV), Saint Louis encephalitis (SLEV), and Oropouche (OROV) viruses are neglected members of the three main families of arboviruses with medical relevance that circulate in the Amazon region as etiological agents of outbreaks of febrile illnesses in humans. As enveloped viruses, MAYV, SLEV, and OROV largely depend on their class II fusion proteins (E1, E, and Gc, respectively) for entry into the host cell. Since many aspects of the structural biology of such proteins remain unclear, the present study aimed at physicochemically characterizing them by an in silico approach. The complete amino acid sequences of MAYV E1, SLEV E, and OROV Gc proteins derived by conceptual translation from annotated coding regions in the reference sequence genome of the respective viruses were obtained from the NCBI Protein database in the FASTA format and then submitted to the ClustalO, Protcalc, Pepstats, Predator, Proscan, PCprof, Phyre2, and 3Drefine web servers for the determination of sequence identities, the estimation of residual properties, the prediction of secondary structures, the identification of potential post-translational modifications, the recognition of antigenic propensities, and the modeling/refinement of three-dimensional structures. Sequence identities were 20.44%, 18.82%, and 13.70% between MAYV/SLEV, SLEV/OROV, and MAYV/OROV fusion proteins, respectively. As for the residual properties, MAYV E1 and SLEV E proteins showed a predominance of the non-polar profile (56% and 55% of the residues, respectively), whereas the OROV Gc protein showed a predominance of the polar profile (52% of the residues). Regarding predicted secondary structures, MAYV E1 and SLEV E proteins showed fewer alpha-helices (16.51% and 15.17%, respectively) than beta-sheets (21.79% and 25.15%, respectively), while the opposite was observed in the OROV Gc protein (20.39% alpha-helices and 12.14% beta-sheets). Regarding post-translational modifications, MAYV E1, SLEV E, and OROV Gc proteins showed greater relative potential for protein kinase C phosphorylation, N-myristoylation, and casein kinase II phosphorylation, respectively. Finally, antigenic propensities were higher in the N-terminus half than in the C-terminus half of these three proteins, whose three-dimensional structures revealed three distinctive domains. In conclusion, MAYV E1 and SLEV E proteins were found to share more physicochemical characteristics with each other than the OROV Gc protein, although they are all grouped under the same class of viral fusion proteins. Full article

Djeya1 (RKLAFRYRRIKELYNSYR) is a very effective cell penetrating peptide (CPP) that mimics the α5 helix of the highly conserved Eya domain (ED) of eyes absent (Eya) proteins. The objective of this study was to bioengineer analogues of Djeya1 that, following effective translocation into planarian tissues, would reduce the ability of neoblasts (totipotent stem cells) and their progeny to regenerate the anterior pole in decapitated S. mediterranea. As a strategy to increase the propensity for helix formation, molecular bioengineering of Djeya1 was achieved by the mono-substitution of the helicogenic aminoisobutyric acid (Aib) at three species-variable sites: 10, 13, and 16. CD analyses indicated that Djeya1 is highly helical, and that Aib-substitution had subtle influences upon the secondary structures of bioengineered analogues. Aib-substituted Djeya1 analogues are highly efficient CPPs, devoid of influence upon cell viability or proliferation. All three peptides increase the migration of PC-3 cells, a prostate cancer line that expresses high concentrations of Eya. Two peptides, [Aib¹³]Djeya1 and [Aib¹⁶]Djeya1, are bioportides which delay planarian head regeneration. As neoblasts are the only cell population capable of division in planaria, these data indicate that bioportide technologies could be utilised to directly manipulate other stem cells in situ, thus negating any requirement for genetic manipulation. Full article

Dynein, a homodimeric protein complex, plays a pivotal role in retrograde transportation along microtubules within cells. It consists of various subunits, among which the light intermediate chain (LIC) performs diverse functions, including cargo adaptor binding. In contrast to the vertebrate LIC homolog LIC1, LIC2 has received relatively limited characterization thus far, despite partially orthogonal functional roles. In this study, we present a near-to-complete backbone NMR chemical shift assignment of the C-terminal region of the light intermediate chain 2 of human dynein 1 (LIC2-C). We perform a comparative analysis of the secondary structure propensity of LIC2-C with the one previously reported for LIC1-C and show that the two transient helices in LIC1 that interact with motor adaptors are also present in LIC2. Full article

Quality control-associated proteolysis (QCAP) is a fundamental mechanism that maintains cellular homeostasis by eliminating improperly folded proteins. In QCAP, the exposure of normally hidden cis-acting protein sequences, termed degrons, triggers misfolded protein ubiquitination, resulting in their elimination by the proteasome. To identify the landscape of QCAP degrons and learn about their unique features we have developed an unbiased screening method in yeast, termed yGPS-P, which facilitates the determination of thousands of proteome-derived sequences that enhance proteolysis. Here we describe the fundamental features of the yGPS-P method and provide a detailed protocol for its use as a tool for degron search. This includes the cloning of a synthetic peptidome library in a fluorescence-based reporter system, and data acquisition, which entails the combination of Fluorescence-Activated Cell Sorting (FACS) and Next-Generation Sequencing (NGS). We also provide guidelines for data extraction and analysis and for the application of a machine-learning algorithm that established the evolutionarily conserved amino acid preferences and secondary structure propensities of QCAP degrons. Full article