Search

Several drug screening campaigns identified Calpeptin as a drug candidate against SARS-CoV-2. Initially reported to target the viral main protease (Mpro), its moderate activity in Mpro inhibition assays hints at a second target. Indeed, we show that Calpeptin is an extremely potent cysteine cathepsin inhibitor, a finding additionally supported by X-ray crystallography. Cell infection assays proved Calpeptin’s efficacy against SARS-CoV-2. Treatment of SARS-CoV-2-infected Golden Syrian hamsters with sulfonated Calpeptin at a dose of 1 mg/kg body weight significantly reduces the viral load in the trachea. Our results show that the inhibition of cathepsins, a protein family of the host organism, is a promising approach for the treatment of SARS-CoV-2 and potentially other viral infections. An intrinsic advantage in targeting host proteins is their mutational stability in contrast to highly mutable viral targets.

Nanomaterials with a defined composition and structure can be synthesized by exploiting natural templates or biomolecular matrices. In the present work, we use protein nanocages derived from human ferritin as a nanoscale building block for the assembly of gold nanoparticles and fluorescent molecules in the solid state. As a generalizable strategy, we show that prior to material synthesis, the cargo can be encapsulated into the protein nanocages using a dis- and reassembly approach. Toward this end, a new ligand system for gold nanoparticles enables efficient encapsulation of these particles into the nanocages. The gold nanoparticle-loaded protein nanocages are co-assembled with fluorophore-loaded protein nanocages. Binary superlattices are formed because two oppositely charged ferritin nanocages are used as templates for the assembly. The binary crystals show strong exciton-plasmon coupling between the encapsulated fluorophores and gold nanoparticles, which was spatially resolved with fluorescence lifetime imaging. The strategy outlined here offers a modular approach toward binary nanomaterials with highly ordered building blocks.

Hemodialysis fails to remove protein-bound uremic toxins that are attributed with high cardiovascular risk. Application of adsorption materials is a viable strategy, but suitable biocompatible adsorbents are still not available. Here, we demonstrate that adsorbents based on the bottom-up assembly of the intrinsically biocompatible protein cage ferritin are applicable for toxin adsorption. Due to the size-exclusion effect of its pores, only small molecules such as uremic toxins can enter the protein cage. Protein redesign techniques that target selectively the inner surface were used to introduce anchor sites for chemical modification. Porous crystalline adsorbents were fabricated by bottom-up assembly of the protein cage. Linkage of up to 96 phenylic or aliphatic molecules per container was verified by ESI-MS. Materials based on unmodified ferritin cages can already adsorb the uremic toxins. The adsorption capacity could be increased by about 50% through functionalization with hydrophobic molecules reaching 458 μg g-1 for indoxyl sulfate. The biohybrid materials show no contamination with endotoxins and do not activate blood platelets. These findings demonstrate the great potential of protein-based adsorbents for the clearance of uremic toxins: modifications enhance toxin adsorption without diminishing the biocompatibility of the final protein-based material.

Hypothesis: The application of ferritin containers as a promising drug delivery vehicle is limited by their low bioavailability in blood circulation due to unfavorable environments, such as degradation by protease. The integration of ferritin containers into the polymeric network of microgels through electrostatic interactions is expected to be able to protect ferritin against degradation by protease. Furthermore, a stimuli-responsive microgel system can be designed by employing an acid-degradable crosslinker during the microgel synthesis. This should enable ferritin release in an acidic environment, which will be useful for future drug delivery applications.Experiments: Nanoparticle/fluorophores-loaded ferritin was integrated into microgels during precipitation polymerization. The integration was monitored by transmission electron microscopy (TEM)2 and fluorescence microscopy, respectively. After studying ferritin release in acidic solutions, we investigated the stability of ferritin inside microgels against degradation by chymotrypsin.Findings: About 80% of the applied ferritin containers were integrated into microgels and around 85% and 50% of them could be released in buffer pH 2.5 and 4.0, respectively. Total degradation of the microgels was not achieved due to the self-crosslinking of N-isopropylacrylamide (NIPAM). Finally, we prove that microgels could protect ferritin against degradation by chymotrypsin at 37 degrees C. (C) 2021 Elsevier Inc. All rights reserved.

This minireview provides an overview on the current knowledge of protein–protein interactions, common characterisation methods to characterise them, and their role in protein complex formation with some examples. A deep understanding of protein–protein interactions and their molecular interactions is important for a number of applications, including drug design. Protein–protein interactions and their discovery are thus an interesting avenue for understanding how protein complexes, which make up the majority of proteins, work.

Small and hyperostotic tympanic bone spicules (STBS and HTBS) extending from the tympanic wall or from the septum bullae into the tympanic cavity have been described in large feline species such as Siberian tigers or African lions and in canids such as dogs, red foxes and wolves. Detailed descriptions of prevalence, location and orientation were performed for dogs and African lions by means of necropsy and conventional computed tomography (cCT). Aims of the current study were to describe same characteristics for domestic cats by means of microcomputed tomography (µCT) and cCT. A total of 15 cats or rather 30 ears were examined. Furthermore, new bone formations extending into the tympanic cavity shaped like small lamellae were found and named "tympanic bone crests" (TBCs). The registered phenomenon of a thickened tympanic wall in some cats was named "tympanic wall thickening" (TWT). STBS appeared in 43% of the ears being bilateral in 44% of the cases, whereas HTBS appeared in one ear. TBC was present in 33% of the ears with a bilateral prevalence of 67%, and TWT could be detected in 13% of the ears. The mentioned structures are just barely or not at all detectable with cCT; therefore, µCT is necessary for an identification and detailed description. The origin and the factors inducing the development of examined phenomena are unknown, and it is hypothesized that the occurrence can be assessed as anatomical norm variations.

Insects : open access journal 12(7), 636 (2021). doi:10.3390/insects12070636 special issue: "Special issue "Insecticides for mosquito control: strengthening the evidence base" / special issue editor: Rosemary S. Lees, guest editor", Published by MDPI, Basel

The assembly of molecular building blocks into highly ordered structures is crucial, both in nature and for the development of novel functional materials. In nature, noncovalent interactions, such as hydrogen bonds or hydrophobic interactions, enable the reversible assembly of biopolymers, such as DNA or proteins. Inspired by these design principles, scientists have created biohybrid materials that employ natural building blocks and their assembly properties. Thus, structures and materials are attainable that cannot be made through other synthetic procedures. Herein, we review current concepts and highlight recent advances.

A large-scale screen to target SARS-CoV-2 The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome is initially expressed as two large polyproteins. Its main protease, Mpro, is essential to yield functional viral proteins, making it a key drug target. Günther et al. used x-ray crystallography to screen more than 5000 compounds that are either approved drugs or drugs in clinical trials. The screen identified 37 compounds that bind to Mpro. High-resolution structures showed that most compounds bind at the active site but also revealed two allosteric sites where binding of a drug causes conformational changes that affect the active site. In cell-based assays, seven compounds had antiviral activity without toxicity. The most potent, calpeptin, binds covalently in the active site, whereas the second most potent, pelitinib, binds at an allosteric site. Science, this issue p. 642, A repurposed drug-library screen reveals two allosteric drug binding sites of the SARS-CoV-2 main protease., The coronavirus disease (COVID-19) caused by SARS-CoV-2 is creating tremendous human suffering. To date, no effective drug is available to directly treat the disease. In a search for a drug against COVID-19, we have performed a high-throughput x-ray crystallographic screen of two repurposing drug libraries against the SARS-CoV-2 main protease (Mpro), which is essential for viral replication. In contrast to commonly applied x-ray fragment screening experiments with molecules of low complexity, our screen tested already-approved drugs and drugs in clinical trials. From the three-dimensional protein structures, we identified 37 compounds that bind to Mpro. In subsequent cell-based viral reduction assays, one peptidomimetic and six nonpeptidic compounds showed antiviral activity at nontoxic concentrations. We identified two allosteric binding sites representing attractive targets for drug development against SARS-CoV-2.

The transition of the powertrain from combustion to electric systems increases the demand for reliable copper connections. For such applications, laser welding has become a key technology. Due to the complexity of laser welding, especially at micro welding with small weld seam dimensions and short process times, reliable in-line process monitoring has proven to be difficult. By using a green laser with a wavelength of λ=515, the welding process of copper benefits from an increased absorption, resulting in a shallow and stable deep penetration welding process. This opens up new possibilities for the process monitoring. In this contribution, the monitoring of the capillary depth in micro copper welding, with welding depth of up to 1 , was performed coaxially using an optical coherence tomography (OCT) system. By comparing the measured capillary depth and the actual welding depth, a good correlation between two measured values could be shown independently of the investigated process parameters and stability. Measuring the capillary depth allows a direct determination of the present aspect ratio in the welding process. For deep penetration welding, aspect ratios as low as 0.35 could be shown. By using an additional scanning system to superimpose the welding motion with a spacial oscillating of the OCT beam perpendicular to the welding motion, multiple information about the process could be determined. Using this method, several process information can be measured simultaneously and is shown for the weld seam width exemplarily.

A nontraumatic spontaneous spinal acute subdural hematoma (sSDH) is a rare complication after spinal surgery. Although an sSDH is often associated with anticoagulation therapy, vascular malformations, or lumbar puncture, the pathogenesis of nontraumatic spontaneous sSDH remains unclear. We present the case of an intradural hematoma after an extraforaminal surgery through the Wiltse approach for an extraforaminal disk herniation at L5/S1. This 58-year-old woman experienced hypoesthesia and progressive motor dysfunction in the left leg several hours postoperation. Urgent magnetic resonance imaging revealed an intradural hematoma at the L1/L2 to L2/L3 level in the ventral dural sac proximal to the surgical level. Surgical decompression was performed. There was no evidence of trauma, coagulopathy, or anticoagulation therapy. To our knowledge, this case is the first to report an acute sSDH proximal to the surgery level after an extraforaminal spinal surgery through the Wiltse approach for an extraforaminal disk herniation. It illustrates that attentive postoperative neurologic monitoring, even in the absence of intraoperative irregularities, remains important to diagnose and treat this complication at the early stage.

The coronavirus disease (COVID-19) caused by SARS-CoV-2 is creating tremendous health problems and economical challenges for mankind. To date, no effective drug is available to directly treat the disease and prevent virus spreading. In a search for a drug against COVID-19, we have performed a massive X-ray crystallographic screen of two repurposing drug libraries against the SARS-CoV-2 main protease (Mpro), which is essential for the virus replication and, thus, a potent drug target. In contrast to commonly applied X-ray fragment screening experiments with molecules of low complexity, our screen tested already approved drugs and drugs in clinical trials. From the three-dimensional protein structures, we identified 37 compounds binding to Mpro. In subsequent cell-based viral reduction assays, one peptidomimetic and five non-peptidic compounds showed antiviral activity at non-toxic concentrations. We identified two allosteric binding sites representing attractive targets for drug development against SARS-CoV-2.

Here we present the crystal structure of SARS-CoV-2 main protease (Mpro) covalently bound to 2-methyl-1-tetralone. This complex was obtained by co-crystallization of Mpro with HEAT (2-(((4-hydroxyphenethyl)amino)methyl)-3,4-dihydronaphthalen-1(2H)-one) in the framework of a large X-ray crystallographic screening project of Mpro against a drug repurposing library, consisting of 5632 approved drugs or compounds in clinical phase trials. Further investigations showed that HEAT is cleaved by Mpro in an E1cB-like reaction mechanism into 2-methylene-1-tetralone and tyramine. The catalytic Cys145 subsequently binds covalently in a Michael addition to the methylene carbon atom of 2-methylene-1-tetralone. According to this postulated model HEAT is acting in a pro-drug-like fashion. It is metabolized by Mpro, followed by covalent binding of one metabolite to the active site. The structure of the covalent adduct elucidated in this study opens up a new path for developing non-peptidic inhibitors.

I present a novel experimental design to measure lying and mistrust as continuous variables on an individual level. My experiment is a sender-receiver game framed as an investment game. It features two players: firstly, an advisor with complete information (i.e., the sender) who is incentivized to lie about the true value of an optimal investment and, secondly, an investor with incomplete information (i.e., the receiver) who is incentivized to invest optimally and therefore must rely on the alleged optimum reported by the advisor. Due to its continuous message space, this experiment allows observing more differentiated behavior and therefore enables testing of more sophisticated theoretical predictions. I find that the senders lie by overstating the true value of the optimum to an average extent of about 148%, while the receivers suspect them to do so by only 56%. Moreover, my results indicate that the senders make strategic considerations about their potential to manipulate others when deciding about the sizes of their lies. However, I find that the size of the lie and the size of mistrust do not only matter from a strategic perspective but also have an impact on how people perceive their own behavior. Consistent with previous studies, my findings support the conjecture that lying costs increase with the size of the lie. Beyond that, I provide evidence for some endogenous preference for trust. Both players’ behaviors and beliefs are consistent over time. In addition, my classification of both players’ strategies is consistent with their self-assessment of their behavior within the experiment.

Protein containers are suitable building blocks for bioinorganic materials. Here, we show that high concentrations of magnesium ions induce the formation of a unitary protein scaffold, whereas low magnesium concentration leads to a binary protein scaffold. The molecular interactions in the protein scaffold were characterized with X-ray crystallography to high resolution. We show that the unitary framework can be applied for the assembly of inorganic nanoparticles such as metal oxides into highly ordered bioinorganic structures. Our work emphasizes the structural tunability of protein-container-based materials, important for adjusting emerging properties of such materials.

We introduce several new variants of the dice experiment by Fischbacher and Follmi-Heusi (Journal of the European Economic Association 11(3):525–547, 2013) to investigate measures to reduce lying. Hypotheses on the relative performance of these treatments are derived from a straightforward theoretical model. In line with previous research, we find that groups of two subjects lied at least to the same extent as individuals—even in a novel treatment where we assigned to one subject the role of being the other’s monitor. However, we find that our participants hardly lied if they do not benefit and only others do, even if they were in a reciprocal relationship. Thus, we conclude that collaboration on lying mostly happens for personal gain. To mitigate selfish lying, an honesty oath which aims to increase moral awareness turned out to be effective.

Proteins are a powerful scaffold for the organisation of inorganic components in the solid state. Due to the defined atomic structure of the protein scaffold, organometallic complexes and nanoparticles can be arranged with high precision. Moreover, crystalline protein materials are porous and enable confinement of inorganic components on the nanoscale. In this Frontier article, we summarize current strategies for the synthesis of bioinorganic materials and highlight recent examples for application of these materials. Future perspectives are discussed such as tunability of material properties through protein design, and the possibility to produce protein materials in a sustainable manner.

This study analyzes the workings of oath-taking when the decision about lying requires strategic thinking. In a laboratory experiment, the oath leads to more truth telling, but it does not make liars reduce the sizes of their lies. While truth tellers decide faster due to the oath, liars need more time to decide under oath. By analyzing players’ beliefs about their co-players’ mistrust, I find that the oath reduces the extent of strategic reasoning in the decision whether to tell the truth or not. These findings are consistent with the conjecture that the honesty oath works by making the decision to tell the truth less deliberate and more intuitive.

In the field of energy supply for residential and commercial buildings, the optimal operation,system configuration and sizing of generation as well as storage technologies are essential stepsfor cost-efficient investments. In current research, flexibility options for electricity from growing renewableenergies attract attention. One of the considered options is the power-to-gas technology incombination with fuel cells. Linear Programs for optimal system operation exist for example for distributedenergy systems. In this study we propose a Mixed Integer Linear Program of a power-to-gasunit consisting of an electrolyzer, a fuel cell and a hydrogen storage. For the fuel cell a minimum loadand a non-linear efficiency curve is taken into account. The non-linear efficiency curve is approximatedby piecewise linearization. Bilinear products in the modeling of the efficiency curve are beingsubstituted to maintain full power plant sizing and operation functionality. Different fuels, such as naturalgas and hydrogen to be converted in the fuel cell, are implemented as well. As a result, we showthat a detailed model of the non-linear efficiency curve of a fuel cell leads to more accurate results concerningthe system operation. The configuration of system components in the observed energy systemchanges. Especially the battery system experiences a change in sizing and operation. However, solvingtime of the model is increasing dramatically. Our results demonstrate a valuable approach to comparethe results of a Linear Program to a Mixed Integer Linear Program. Hence giving the possibility toevaluate the necessity of detailed over simplified models regarding calculation of cost-effectiveness.

Naturinspiriertes Bauprinzip: Anorganische Nanopartikel konnen mit Biomolekulen zu neuartigen Materialien kombiniert werden.

Talking about purified assembled printed circuit boards (PCBs), e.g. in automotive industry for control of airbag or antilock braking systems (ABS) one of the main issues is the protection against environmental impact. The error-free functionality has to be guaranteed even under extreme conditions and this warranty has to be provided for even a decade. The process of conformal coating is not new but nowadays manufacturer of PCBs starts to use the conformal coating process not only at selected areas, the full board is going to be protected. To keep the costs under control it is inevitable to measure the thickness of the coatings. An intelligent design of the full process chain implementing the conformal coating process are perfect conditions to integrate sensor technology for process control. This feature will describe the implementation of an optical sensor technology for the inspection of the conformal coating process to illustrate the benefit of optical sensors in today's industry.

Hydrophobic uremic toxins accumulate in patients with chronic kidney disease, contributing to a highly increased cardiovascular risk. The clearance of these uremic toxins using current hemodialysis techniques is limited due to their hydrophobicity and their high binding a ffi nity to plasma proteins. Adsorber techniques may be an appropriate alternative to increase hydrophobic uremic toxin removal. We developed an extracorporeal, whole- blood bifunctional adsorber particle consisting of a porous, activated charcoal core with a hydrophilic polyvinylpyrrolidone surface coating. The adsorption capacity was quantified using analytical chromatography after perfusion of the particles with an albumin solution or blood, each containing mixtures of hydrophobic uremic toxins. Atime- dependent increase in hydrophobic uremic toxin adsorption was depicted and all toxins showed a high binding a ffi nity to the adsorber particles. Further, the particle showed a su ffi cient hemocompatibility without significant e ff ects on complement component 5a, thrombin- antithrombin III complex, or thrombocyte concentration in blood in vitro, although leukocyte counts were slightly reduced. In conclusion, the bifunctional adsorber particle with cross- linked polyvinylpyrrolidone coating showed a high adsorption capacity without adverse e ff ects on hemocompatibility in vitro. Thus, it may be an interesting candidate for further in vivo studies with the aim to increase the e ffi ciency of conventional dialysis techniques.

The aim of this study was to analyze whether different fixation methods such as freezing or formaldehyde storage for different periods of time have an influence on the recognition of anatomical relevant structures in the middle and inner ear of the cat with conventional computed tomography (cCT) and micro-computed tomography (µCT). Besides, effects of freeze–thaw cycles on determined structures of the ear were investigated by means of histological slices. Three veterinarians with different radiologic expertise evaluated the scans of 30 dissected cat ears anonymously and scored predefined structures in a five-point scale with reference to visually sharp reproducibility and perfect image quality. The total scores of the different fixation groups as well as the ears within a group were compared with each other. Furthermore, an intra-reader examination including an evaluation of the identifiability of specified structures was performed for both imaging methods. cCT as well as µCT-scans have a very low variation coefficient of 1.6% and 2.3%, respectively. The results for the alterations between the different fixation methods show that the changes for cCT-scans are negligible, as the percentage alteration compared to fresh samples ranges in a very small interval with values from 1.0% better to 1.2% worse. µCT-scans are more influenced by the fixation method with a range from 1.3% better to 6.9% worse values. The scans mostly deteriorated after two freeze–thaw cycles (1.8% worse) and after storing the samples for 1 (2.4% worse), respectively, and 3 weeks in formaldehyde (6.9% worse).

Laser materials processing, e.g. welding/ additive manufacturing with cw sources or surface modification with short and ultra-short pulsed lasers is a highly dynamic process, requiring a sensor with high temporal and spatial resolution for evaluating the result of the treatment. Especially in the context of Industry 4.0, digitalization and predictive maintenance reliable sensors get much more into focus. A major drawback of this photon-material interaction with respect to the acquisition of trustworthy measurement data from the interaction zone is the presence of intense process emissions and steep temperature gradients. Common devices used as sensors for process monitoring, like CMOS/IR cameras or photo diodes, help to get an idea of the resulting quality but the acquired data is always perturbed by hot vapor emerging from the workpiece surface. Sensors based on OCT/ low coherence interferometry are different to all the other technologies because the measurement is not affected by the process emissions and thus open new horizons in laser materials processing. The use of this method in laser applications has risen in the last years. Since its first appearance in 2008 [1], application examples were shown for laser cutting [2], selective laser melting [3], laser micro machining [4], laser drilling [5] and laser welding [6]. For the latter, a huge potential is foreseen [8].

The aim of this study was to check the relevance of using in-vivo micro computed tomography (µCT) for the diagnosis of possible diseases of the middle and inner ear of the cat. Therefore, on the one hand, differences of the detail detectability between the two imaging methods conventional computed tomography (cCT) and in-vivo µCT were analyzed. Six healthy cat ears were dissected and scanned several times and the obtained images were compared with each other. On the other hand, histological slices of all ears were prepared and pictures of defined anatomical structures were taken and compared with the identical sectional plane of the µCT-images. This way it was possible to evaluate the quality and clinical limitations of the in-vivo µCT. The results show that an in-vivo µCT is suitable to analyze even the smallest osseous structures, such as the semicircular ducts, the spiral osseous lamina or the ossicles whereas with the help of cCT it is not possible to identify such small osseous structures because of their blurred and less detailed representation. Delicate soft tissue structures as the membranous labyrinth including hearing and vestibular organ cannot be differentiated with as well in-vivo µCT- as with cCT-images. In-vivo µCT represent a good possibility for more detailed diagnosis of extremely fine structures which cannot be detected with cCT. Histological slices can nonetheless not be replaced by in-vivo µCT due to a too low spatial resolution and the limitations of the in-vivo µCT with regard to the evaluation of soft tissue dense structures.

Nanoscale 11(13), 6497-6497 (2019). doi:10.1039/C9NR90066G, Published by RSC Publ., Cambridge

Biomolecules can be combined with inorganic compounds to unite biological features with the chemical and physical properties of abiotic materials. In particular, protein containers, with their inherent ability to encapsulate cargo molecules, are perfect platforms for the generation of multifunctional assemblies. However, encapsulation of foreign cargo is immensely challenging due to the lack of specific interactions between cargo and container. Here, we demonstrate that the highly specific cargo-loading mechanism of the bacterial nanocompartment encapsulin can be employed for encapsulation of artificial cargo like inorganic nanoparticles. For this purpose, container-filling gold nanoparticles were decorated with a small number of encapsulin cargo-loading peptides. By lock-and-key interaction between the peptides and the peptide-binding pockets on the inner container surface, the nanoparticles are encapsulated into encapsulin with extremely high efficiency. Most notably, peptide binding is independent from external factors such as ionic strength. Cargo-loading peptides may serve as generally applicable tool for efficient and specific encapsulation of cargo molecules into a proteinaceous compartment.