Rotation of the c-Ring Promotes the Curvature Sorting of Monomeric ATP Synthases.

ATP synthases are proteins that catalyse the formation of ATP through the rotatory movement of their membrane-spanning subunit. In mitochondria, ATP synthases are found to arrange as dimers at the high-curved edges of cristae. Here, a direct link is explored between the rotatory movement of ATP synthases and their preference for curved membranes. An active curvature sorting of ATP synthases in lipid nanotubes pulled from giant vesicles is found. Coarse-grained simulations confirm the curvature-seeking behaviour of rotating ATP synthases, promoting reversible and frequent protein-protein contacts. The formation of transient protein dimers relies on the membrane-mediated attractive interaction of the order of 1.5 kB T produced by a hydrophobic mismatch upon protein rotation. Transient dimers are sustained by a conic-like arrangement characterized by a wedge angle of θ ≈ 50°, producing a dynamic coupling between protein shape and membrane curvature. The results suggest a new role of the rotational movement of ATP synthases for their dynamic self-assembly in biological membranes.

Activity modulation of the Escherichia coli F1FO ATP synthase by a designed antimicrobial peptide via cardiolipin sequestering.

Most antimicrobial peptides (AMPs) exert their microbicidal activity through membrane permeabilization. The designed AMP EcDBS1R4 has a cryptic mechanism of action involving the membrane hyperpolarization of Escherichia coli, suggesting that EcDBS1R4 may hinder processes involved in membrane potential dissipation. We show that EcDBS1R4 can sequester cardiolipin, a phospholipid that interacts with several respiratory complexes of E. coli. Among these, F1FO ATP synthase uses membrane potential to fuel ATP synthesis. We found that EcDBS1R4 can modulate the activity of ATP synthase upon partition to membranes containing cardiolipin. Molecular dynamics simulations suggest that EcDBS1R4 alters the membrane environment of the transmembrane FO motor, impairing cardiolipin interactions with the cytoplasmic face of the peripheral stalk that binds the catalytic F1 domain to the FO domain. The proposed mechanism of action, targeting membrane protein function through lipid reorganization may open new venues of research on the mode of action and design of other AMPs.

Quality Tolerance Limits' Place in the Quality Management System and Link to the Statistical Trial Design: Case Studies and Recommendations from Early Adopters.

Since the release of ICH E6(R2), multiple efforts have been made to interpret the requirements and suggest ways of implementing quality tolerance limits (QTLs) alongside existing risk-based quality management methodologies. While these efforts have contributed positively to developing a common understanding of QTLs, some uncertainty remains regarding implementable approaches. In this article, we review the approaches taken by some leading biopharmaceutical companies, offering recommendations for how to make QTLs most effective, what makes them ineffective, and several case studies to illustrate these concepts. This includes how best to choose QTL parameters and thresholds for a given study, how to differentiate QTLs from key risk indicators, and how QTLs relate to critical-to-quality factors and the statistical design of the trials.

Cryogenic mirror position actuator for spectroscopic applications.

We demonstrate a mirror position actuator that operates in a wide temperature range from room temperature to a deep cryogenic regime (10 K). We use a Michelson interferometer to measure the actuator tuning range (and piezoelectric efficiency) in the full temperature range. We demonstrate an unprecedented range of tunability of the mirror position in the cryogenic regime (over 22 µm at 10 K). The capability of controlling the mirror position in the range from few to few tens of microns is crucial for cavity-enhanced molecular spectroscopy techniques, especially in the important mid-infrared spectral regime where the length of an optical cavity has to be tunable in a range larger than the laser wavelength. The piezoelectric actuator offering this range of tunability in the cryogenic conditions, on the one hand, will enable development of optical cavities operating at low temperatures that are crucial for spectroscopy of large molecules whose dense spectra are difficult to resolve at room temperature. On the other hand, this will enable us to increase the accuracy of the measurement of simple molecules aimed at fundamental studies.

Insights into the mode of action of the two-peptide lantibiotic lichenicidin.

Lantibiotics are promising candidates to address the worldwide problem of antibiotic resistance. They belong to a class of natural compounds exhibiting strong activity against clinically relevant Gram-positive bacterial strains, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE). Lichenicidin is a class II two-peptide lantibiotic. The presence of the two mature peptides, Bliα and Bliß, is necessary for full activity against target bacteria. This work aims at clarifying the synergistic activity of both peptides in their interaction with the target membranes. The effect of lichenicidin was tested against S. aureus cells and large unilamellar vesicles. Lichenicidin increases the net surface charge of S. aureus, as shown by zeta-potential measurements, without reaching electroneutralization. In addition, lichenicidin causes cell surface perturbations that culminate in the leakage of its internal contents, as observed by atomic force microscopy. Bliα seems to have low affinity for S. aureus, however, it contributes to increase the affinity of Bliß, because together they present higher affinity than separately. In contrast, Bliα seems to provide an anchoring site for lichenicidin in lipid II-containing membranes. Interestingly, Bliß alone can induce high levels of membrane leakage, but this effect appears to be faster in the presence of Bliα. Based on this information, we propose a mechanism of action of lichenicidin.

Transactional Interpretation and the Generalized Poisson Distribution.

The aim of this paper is to study the quantum-like approach to the description of the market in the context of the principle of minimum Fisher information. We wish to investigate the validity of using squeezed coherent states as market strategies. For this purpose, we focus on the representation of any squeezed coherent state with respect to the basis of the eigenvectors of the observable of market risk. We derive a formula for the probability of being the squeezed coherent state in one of these states. The distribution that we call generalized Poisson establishes the relation between the squeezed coherent states and their description in the language of risk in quantum terms. We provide a formula specifying the total risk of squeezed coherent strategy. Then, we propose a risk of risk concept that is in fact the second central moment of the generalized Poisson distribution. This is an important numerical characterization of squeezed coherent strategies. We provide its interpretations on the basis of the uncertainty relation for time and energy.

Transactional Interpretation for the Principle of Minimum Fisher Information.

The principle of minimum Fisher information states that in the set of acceptable probability distributions characterizing the given system, it is best done by the one that minimizes the corresponding Fisher information. This principle can be applied to transaction processes, the dynamics of which can be interpreted as the market tendency to minimize the information revealed about itself. More information involves higher costs (information is physical). The starting point for our considerations is a description of the market derived from the assumption of minimum Fisher information for a strategy with a fixed financial risk. Strategies of this type that minimize Fisher information overlap with the well-known eigenstates of a the quantum harmonic oscillator. The analytical extension of this field of strategy to the complex vector space (traditional for quantum mechanics) suggests the study of the interference of the oscillator eigenstates in terms of their minimization of Fisher information. It is revealed that the minimum value of Fisher information of the superposition of the two strategies being the ground state and the second excited state of the oscillator, has Fisher information less than the ground state of the oscillator. Similarly, less information is obtained for the system of strategies (the oscillator eigenstates) randomized by the Gibbs distribution. We distinguish two different views on the description of Fisher information. One of them, the classical, is based on the value of Fisher information. The second, we call it transactional, expresses Fisher information from the perspective of the constant risk of market strategies. The orders of the market strategies derived from these two descriptions are different. From a market standpoint, minimizing Fisher information is equivalent to minimizing risk.

Historical Benchmarks for Quality Tolerance Limits Parameters in Clinical Trials.

BACKGROUND: In 2016, the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use updated its efficacy guideline for good clinical practice and introduced quality tolerance limits (QTLs) as a quality control in clinical trials. Previously, TransCelerate proposed a framework for QTL implementation and parameters. Historical data can be important in helping to determine QTL thresholds in new clinical trials. METHODS: This article presents results of historical data analyses for the previously proposed parameters based on data from 294 clinical trials from seven TransCelerate member companies. The differences across therapeutic areas were assessed by comparing Alzheimer's disease (AD) and oncology trials using a separate dataset provided by Medidata. RESULTS: TransCelerate member companies provided historical data on 11 QTL parameters with data sufficient for analysis for parameters. The distribution of values was similar for most parameters with a relatively small number of outlying trials with high parameter values. Medidata provided values for three parameters in a total of 45 AD and oncology trials with no obvious differences between the therapeutic areas. CONCLUSION: Historical parameter values can provide helpful benchmark information for quality control activities in future trials.

Measuring and upscaling micromechanical interactions in a cohesive granular material.

The mechanical properties of a disordered heterogeneous medium depend, in general, on a complex interplay between multiple length scales. Connecting local interactions to macroscopic observables, such as stiffness or fracture, is thus challenging in this type of material. Here, we study the properties of a cohesive granular material composed of glass beads held together by soft polymer bridges. We characterise the mechanical response of single bridges under traction and shear, using a setup based on the deflection of flexible micropipettes. These measurements, along with information from X-ray microtomograms of the granular packings, then inform large-scale discrete element model (DEM) simulations. Although simple, these simulations are constrained in every way by empirical measurement and accurately predict mechanical responses of the aggregates, including details on their compressive failure, and how the material's stiffness depends on the stiffness and geometry of its parts. By demonstrating how to accurately relate microscopic information to macroscopic properties, these results provide new perspectives for predicting the behaviour of complex disordered materials, such as porous rock, snow, or foam.

Lipid membrane-based therapeutics and diagnostics.

Success rates in drug discovery are extremely low, and the imbalance between new drugs entering clinical research and their approval is steadily widening. Among the causes of the failure of new therapeutic agents are the lack of safety and insufficient efficacy. On the other hand, timely disease diagnosis may enable an early management of the disease, generally leading to better and less costly outcomes. Several strategies have been explored to overcome the barriers for drug development and facilitate diagnosis. Using lipid membranes as platforms for drug delivery or as biosensors are promising strategies, due to their biocompatibility and unique physicochemical properties. We examine some of the lipid membrane-based strategies for drug delivery and diagnostics, including their advantages and shortcomings. Regarding synthetic lipid membrane-based strategies for drug delivery, liposomes are the archetypic example of a successful approach, already with a long period of well-succeeded clinical application. The use of lipid membrane-based structures from biological sources as drug carriers, currently under clinical evaluation, is also discussed. These biomimetic strategies can enhance the in vivo lifetime of drug and delivery system by avoiding fast clearance, consequently increasing their therapeutic window. The strategies under development using lipid membranes for diagnostic purposes are also reviewed.

Quality Tolerance Limits: Framework for Successful Implementation in Clinical Development.

The International Council for Harmonisation (ICH) E6(R2) (International Council for Harmonisation (ICH). ICH harmonised guideline: integrated addendum to ICH E6(R1): guideline for good clinical practice E6(R2). 2016. https://database.ich.org/sites/default/files/E6_R2_Addendum.pdf . Accessed 5 Dec 2019) introduced Quality Tolerance Limits (QTLs) to the industry, and in doing so, modernized quality control for clinical trials. QTLs provide measured feedback on clinical trial parameters previously only used by statistical and clinical functions to track trial progress toward endpoints. Elevating these measures as part of the Quality Management System (QMS) provides greater visibility across clinical trial functions and the enterprise as well as to measures that are important indicators of the state of participant protection and reliability of trial results. In support of this new requirement, TransCelerate developed a framework to guide industry sponsors and their agents in implementing QTLs. This QTL Framework is intended to aid industry's ability to improve the quality of clinical research through the implementation of QTLs in a way that helps protect trial participants and reliability of trial results while meeting Health Authority (HA) expectations. The framework is intended to maximize efficiency and minimize confusion in the implementation of QTLs. The framework includes proposed approaches for implementation of QTLs for a clinical trial as defined in Section 5.0.4 and 5.0.7 of ICH E6(R2) (International Council for Harmonisation (ICH). ICH harmonised guideline: integrated addendum to ICH E6(R1): guideline for good clinical practice E6(R2). 2016. https://database.ich.org/sites/default/files/E6_R2_Addendum.pdf . Accessed 5 Dec 2019) and considerations for setting thresholds.

Cardiovascular complications in patients with idiopathic inflammatory myopathies: does heart matter in idiopathic inflammatory myopathies?

This review presents a detailed study of original researches and previously published reviews concerning cardiovascular involvement in idiopathic inflammatory myopathies (IIM). We aimed to summarize the current knowledge on the cardiac involvement in IIM, evaluate its impact on mortality and indicate areas still awaiting to be investigated. We searched MEDLINE database (until January 2019) and the reference lists of articles. Selection criteria included only published data, available in English, both original researches and reviews. Articles related to cardiovascular involvement in IIM were selected and analysed. The references were also screened, and relevant articles were included. Cardiovascular involvement is frequent in IIM but typically remains subclinical. Among far less prevalent symptomatic forms, congestive heart failure is the most common. Myocardium and conduction system seems to be predominantly affected. High rate of left ventricular diastolic dysfunction was observed. Non-specific changes of ST-T segment were the most common abnormalities in electrocardiography. Patients with IIM were more frequently affected by atrial fibrillation as compared with other autoimmune diseases. Increased risk of myocardial infarction was observed; furthermore, patients often develop comorbidities that enhance cardiovascular risk. Since cardiovascular disorders remain one of the major causes of death and subclinical involvement is frequent, active screening is justified. Growing availability of the novel imaging techniques may facilitate diagnosis. Correlation between myocardial involvement and the type of autoantibodies and impact of different therapeutic options on the progression of cardiovascular lesions require further studies.

EcDBS1R4, an Antimicrobial Peptide Effective against Escherichia coli with In Vitro Fusogenic Ability.

Discovering antibiotic molecules able to hold the growing spread of antimicrobial resistance is one of the most urgent endeavors that public health must tackle. The case of Gram-negative bacterial pathogens is of special concern, as they are intrinsically resistant to many antibiotics, due to an outer membrane that constitutes an effective permeability barrier. Antimicrobial peptides (AMPs) have been pointed out as potential alternatives to conventional antibiotics, as their main mechanism of action is membrane disruption, arguably less prone to elicit resistance in pathogens. Here, we investigate the in vitro activity and selectivity of EcDBS1R4, a bioinspired AMP. To this purpose, we have used bacterial cells and model membrane systems mimicking both the inner and the outer membranes of Escherichia coli, and a variety of optical spectroscopic methodologies. EcDBS1R4 is effective against the Gram-negative E. coli, ineffective against the Gram-positive Staphylococcus aureus and noncytotoxic for human cells. EcDBS1R4 does not form stable pores in E. coli, as the peptide does not dissipate its membrane potential, suggesting an unusual mechanism of action. Interestingly, EcDBS1R4 promotes a hemi-fusion of vesicles mimicking the inner membrane of E. coli. This fusogenic ability of EcDBS1R4 requires the presence of phospholipids with a negative curvature and a negative charge. This finding suggests that EcDBS1R4 promotes a large lipid spatial reorganization able to reshape membrane curvature, with interesting biological implications herein discussed.

Refractory Angina-Unsolved Problem.

The article discusses pharmacologic and interventional therapeutic options for patients with refractory angina. Refractory angina refers to long-lasting symptoms (≥3 months) due to established reversible ischemia in the presence of obstructive coronary artery disease, which cannot be controlled by escalating medical therapy with second-line and third-line pharmacologic agents, bypass grafting, or stenting. Due to an aging population, increased number of comorbidities, and advances in coronary artery disease treatment, incidence of refractory angina is growing. Although the number of therapeutic options is increasing, there is a lack of randomized clinical trials that could help create recommendations for this group of patients.

Interleukin-33/suppression of tumorigenicity 2 (IL-33/ST2) axis in idiopathic inflammatory myopathies and its association with laboratory and clinical parameters: a pilot study.

Idiopathic inflammatory myopathies (IIM) are rare connective tissue diseases, which can lead to internal organ involvement. IL-33/ST2 pathway is involved in the pathogenesis of numerous diseases including autoimmune disorders. IL-33 fulfils cardioprotective function, while soluble ST2 (sST2) is a decoy receptor that reduces protective impact of IL-33. The aim of the study was to evaluate the concentrations of sST2 and IL-33 in sera of patients with IIM and evaluate its associations with the clinical course of the disease. Patients with IIM as well as age- and sex-matched healthy controls were recruited. Concentrations of sST2 and IL-33 were assessed with ELISA in sera of both patients and controls. Patients were asked to fill in the questionnaires concerning clinical symptoms and physical functioning. Concentrations of sST2 and IL-33 were correlated with the results of laboratory tests and clinical symptoms. Concentrations of sST2 were significantly higher in IIM group than in healthy subjects (median sST2 in IIM 26.51 vs in healthy controls 21.39; p = 0.03). In the majority of patients, IL-33 concentrations did not exceed the detection limit. Anti-SRP-positive patients presented significantly higher concentrations of sST2 as compared to anti-SRP-negative patients (p = 0.04). In patients with anti-Ro52 antibodies, sST2 concentrations were significantly lower than in anti-Ro52-negative patients (p = 0.02). Concentrations of sST2 correlated with the degree of disability evaluated with Health Assessment Questionnaire. sST2 is increased in patients with IIM and its concentration correlates with the degree of disability. In patients with anti-SRP antibodies, levels of sST2 are exceptionally high.

Spectroscopic and theoretical studies of fluorescence effects induced by the ESIPT process in a new derivative 2-Hydroxy-N-(2-phenylethyl)benzamide - Study on the effects of pH and medium polarity changes.

The paper presents the results of studies conducted with the use of stationary and time-resolved fluorescence spectroscopy for the new derivative 2-Hydroxy-N-(2-phenylethyl)benzamide (SAL-3) in aqueous solutions with various concentrations of hydrogen ions as well as in solvent mixtures (i.e. media with changing polarity/polarizability). For the compound selected for the study placed in aqueous solutions with varying concentrations of hydrogen ions, the fluorescence emission spectra revealed a single emission band within most of the pH range, however, at low pH (pH<3) a significant broadening (noticeable effect of dual fluorescence) and shifting of the band was observed. Whereas, for water and polar (protic) solvents, we observed a very interesting phenomenon of dual fluorescence never before reported for this particular group of analogues (with the specific substituent system). Based on the results of the experiments, it was observed that the presented effects may be related both with conformational effects (related to the possible positioning of the-OH group on the side of the carbonyl system, which facilitates the possibility of proton transfer) as well as, most importantly, the effects of excited state intramolecular proton transfer (ESIPT-Excited State Intramolecular Proton Transfer) related in this case with the necessary (new/previously unobserved in published literature) presence of ionic and non-ionic forms of the compound). Both the conducted quantum-mechanical [TD]DFT-Time-Dependent Density Functional Theory) calculations and excited state dipole moment change calculations for the analyzed molecule in solvents with varying pH confirmed the association between the observed fluorescence phenomena and the two aforementioned effects.

Advances in Lipid and Metal Nanoparticles for Antimicrobial Peptide Delivery.

Antimicrobial peptides (AMPs) have been described as excellent candidates to overcome antibiotic resistance. Frequently, AMPs exhibit a wide therapeutic window, with low cytotoxicity and broad-spectrum antimicrobial activity against a variety of pathogens. In addition, some AMPs are also able to modulate the immune response, decreasing potential harmful effects such as sepsis. Despite these benefits, only a few formulations have successfully reached clinics. A common flaw in the druggability of AMPs is their poor pharmacokinetics, common to several peptide drugs, as they may be degraded by a myriad of proteases inside the organism. The combination of AMPs with carrier nanoparticles to improve delivery may enhance their half-life, decreasing the dosage and thus, reducing production costs and eventual toxicity. Here, we present the most recent advances in lipid and metal nanodevices for AMP delivery, with a special focus on metal nanoparticles and liposome formulations.

Non-Typical Fluorescence Effects and Biological Activity in Selected 1,3,4-thiadiazole Derivatives: Spectroscopic and Theoretical Studies on Substituent, Molecular Aggregation, and pH Effects.

The below article presents the results of spectroscopic research, theoretical (time-dependent density functional theory (TD-DFT)), microbiological, and antioxidative calculations for three compounds from the group of 1,3,4-thiadiazoles: 2-amino-5-phenyl-1,3,4-thiadiazole (TB), 2-amino-5-(2-hydroxyphenyl)-1,3,4-thiadiazole (TS), 2-amino-5-(2-hydroxy-5-sulfobenzoyl)-1,3,4-thiadiazole (TSF). In the fluorescence emission spectra (TS) of solutions with varying concentrations of hydrogen ions, a particularly interesting effect of dual fluorescence was observed. The aforementioned effect was observed even more clearly in the environment of butan-1-ol, relative to the compound's concentration. Depending on the modification of the resorcylic substituent (TS and TSF), we observed the emergence of two separate, partially overlapping, fluorescence emission spectra or a single emission spectrum. Interpretation of the obtained spectra using stationary and time-resolved spectroscopy allowed the correlation of the effect's emergence with the phenomenon of molecular aggregation (of a particular type) as well as, above all, the structure of the substituent system. The overlap of said effects most likely induces the processes related to the phenomenon of charge transfer (in TS) and is responsible for the observed fluorescence effects. Also, the position of the -OH group (in the resorcylic ring) is significant and can facilitate the charge transfer (CT). The determinations of the changes in the dipole moment and TD-DFT calculations further corroborate the above assumption. The following paper presents the analysis (the first for this particular group of analogues) of the fluorescence effects relative to the changes in the structure of the resorcylic group combined with pH effects. The results of biological studies also indicate the highest pharmacological potential of the analogue in the case where the effects of dual fluorescence emission are observed, which predisposes this particular group of fluorophores as effective fluorescence probes or potential pharmaceuticals with antimycotic properties.

Effect of Antazoline on Electrophysiological Properties of Atrial Muscle and Conduction System of the Heart.

PURPOSE: Antazoline is a first-generation antihistaminic agent with additional anticholinergic properties and antiarrhythmic potential. Recent data shows its high effectiveness in sinus rhythm restoration among patients with paroxysmal atrial fibrillation. The effect of antazoline on electrophysiological parameters of the heart in vivo has not yet been examined. The aim of this study was to evaluate changes in electrophysiological parameters of the heart muscle and conduction system as a response to increasing doses of antazoline. METHODS: After successful ablation of supraventricular arrhythmias, the electrophysiological parameters: sinus rhythm cycle length (SRCL), AH, HV, QRS, QT, QTc intervals, Wenckebach point (WP), sinus node recovery period (SNRT), intra- (hRA-CSos) and interatrial conduction time (hRA-CSd), right and left atrium refractory period (RA-; LA-ERP), and atrioventricular node refractory period (AVN-ERP) were assessed initially and after 100, 200, and 300 mg of antazoline given intravenously. RESULTS: Fifteen patients (8 males, 19-72 years old) undergoing EPS and RF ablation were enrolled. After 100 mg bolus, a significant reduction in SRCL was noticed. After antazoline administration, significant prolongation of HV, QRS, QTc, hRA-CSos, hRA-CSd intervals, RA- and LA-ERP and reduction of SRCL were observed. After a total dose of 300 mg, QT interval prolonged significantly. Increasing the dose of antazoline had no impact on AH, Wenckebach point, AVN-ERP, and SNRT. CONCLUSION: Antazoline has an effect on electrophysiological parameters of the atrial muscle and has rapid onset of action. No negative effect on sinus node function and atrioventricular conduction in a unique property among antiarrhythmic drugs.