PLOS ONE: [sortOrder=DATE_NEWEST_FIRST, sort=Date, newest first, q=subject:"Structural characterization"]PLOShttps://journals.plos.org/plosone/webmaster@plos.orgaccelerating the publication of peer-reviewed sciencehttps://journals.plos.org/plosone/search/feed/atom?sortOrder=DATE_NEWEST_FIRST&unformattedQuery=subject:%22Structural+characterization%22&sort=Date,+newest+firstAll PLOS articles are Open Access.https://journals.plos.org/plosone/resource/img/favicon.icohttps://journals.plos.org/plosone/resource/img/favicon.ico2024-03-28T23:56:20ZIn situ potassium and hydrogen ion exchange into a cubic zirconium silicate microporous materialJason LivelyAaron J. Celestian10.1371/journal.pone.02986612024-03-21T14:00:00Z2024-03-21T14:00:00Z<p>by Jason Lively, Aaron J. Celestian</p>
The selective separation of ions from aqueous systems, and even in the human body, is a crucial to overall environmental management and health. Nanoporous materials are widely known for their selective removal of cations from aqueous media, and therefore have been targeted for use as a pharmaceutical to treat hyperkalemia. This study investigated the detailed crystallographic molecular mechanisms that control the potassium ion selectivity in the nanoporous cubic zirconium silicate (CZS) related materials. Using time-resolved <i>in situ</i> Raman spectroscopy and time-resolved <i>in situ</i> X-ray diffraction, the selectivity mechanisms were determined to involve a synchronous cation-cation repulsion process that serves to open a favorable coordination bonding environment for potassium, not unlike the ion selectivity filter process found in potassium ion channels in proteins. Enhancement of ion exchange was observed when the CZS material was in a partial protonated state (≈3:1 Na:H), causing an expansion of the unit-cell volume, enlargement of the 7 member-ring window, and distortion of framework polyhedra, which allowed increased accessibility to the cage structures and resulted in rapid irreversible potassium ion exchange.Structural insights into the modulation Of SOD1 aggregation By a fungal metabolite Phialomustin-B: Therapeutic potential in ALSSruthi UnniPadmini KommuSnehal AoutiYedukondalu NalliM. M. Srinivas BharathAsif AliBalasundaram Padmanabhan10.1371/journal.pone.02981962024-03-06T14:00:00Z2024-03-06T14:00:00Z<p>by Sruthi Unni, Padmini Kommu, Snehal Aouti, Yedukondalu Nalli, M. M. Srinivas Bharath, Asif Ali, Balasundaram Padmanabhan</p>
Amyotrophic lateral sclerosis (ALS) is a fatal human motor neuron disease leading to muscle atrophy and paralysis. Mutations in superoxide dismutase 1 (SOD1) are associated with familial ALS (fALS). The SOD1 mutants in ALS have a toxic-gain of function by destabilizing the functional SOD1 homodimer, consequently inducing fibril-like aggregation with a cytotoxic non-native trimer intermediate. Therefore, reducing SOD1 oligomerization <i>via</i> chemical modulators is an optimal therapy in ALS. Here, we report the discovery of Phialomustin-B, an unsaturated secondary metabolite from the endophytic fungus <i>Phialophora mustea</i>, as a modulator of SOD1 aggregation. The crystal structure of the SOD1-Phialomustin complex refined to 1.90 Å resolution demonstrated for the first time that the ligand binds to the dimer interface and the lateral region near the electrostatic loop. The aggregation analyses of SOD1<sup>WT</sup> and the disease mutant SOD1<sup>A4V</sup> revealed that Phialomustin-B reduces cytotoxic trimerization. We propose that Phialomustin-B is a potent lead molecule with therapeutic potential in fALS.Formulation and characterization of glipizide solid dosage form with enhanced solubilityBadriyah Shadid AlotaibiMuhammad Ahsan KhanKaleem UllahHaya YasinAbdul MannanShujaat Ali KhanGhulam Murtaza10.1371/journal.pone.02974672024-02-23T14:00:00Z2024-02-23T14:00:00Z<p>by Badriyah Shadid Alotaibi, Muhammad Ahsan Khan, Kaleem Ullah, Haya Yasin, Abdul Mannan, Shujaat Ali Khan, Ghulam Murtaza</p>
Glipizide, a poor water-soluble drug belongs to BCS class II. The proposed work aimed to enhance the solubility of glipizide by preparing solid dispersions, using polyvinyl pyrrolidone (PVP) and polyethylene glycol (PEG). Solvent evaporation method was used for the preparation of glipizide solid dispersions. Solid dispersions were prepared in four different drug-to-polymer ratios i.e. 1:1, 1:2, 1:3 and 1:4. Mainly effect of three polymers (PVP K30, PVP K90 and PEG 6000) was evaluated on the solubility and dissolution of glipizide. The <i>in-vitro</i> dissolution of all prepared formulations was performed under pH 6.8 at 37°C using USP type II apparatus. <i>In-vitro</i> dissolution results revealed that the formulations having high concentrations of the polymer showed enhanced solubility. Enhancements in the solubility and rate of dissolution of the drug were noted in solid dispersion formulations compared to the physical blends and pure drug. Solid dispersions containing polyvinyl pyrrolidone exhibited a more favorable pattern of drug release compared to the corresponding solid dispersions with PEG. An increase in the maximum solubility of the drug within the solid dispersion systems was observed in all instances. Two solid dispersion formulations were optimized and formulated into immediate-release tablets, which passed all the pharmacopoeial and non-pharmacopoeial tests. Fourier transformed Infrared (FTIR) spectroscopy X-ray diffraction (XRD) and Differential scanning calorimetry (DSC) were used to indicate drug: polymer interactions in solid state. Analysis of the solid dispersion samples through characterization tests indicated the compatibility between the drug and the polymer.Optimization of physical and dielectric properties of Co-doped ZnO nanoparticles for low-frequency devicesAdil MuhammadMuhammad SajidMuhammad Nouman KhanMuhammed SherazAwais KhalidPervaiz AhmadSatam AlotibiHamed M. Al-saidiNebras SobahiMd Mottahir AlamSultan AlthahbanAhmad M. SaeediHasan B. Albargi10.1371/journal.pone.02873222023-11-22T14:00:00Z2023-11-22T14:00:00Z<p>by Adil Muhammad, Muhammad Sajid, Muhammad Nouman Khan, Muhammed Sheraz, Awais Khalid, Pervaiz Ahmad, Satam Alotibi, Hamed M. Al-saidi, Nebras Sobahi, Md Mottahir Alam, Sultan Althahban, Ahmad M. Saeedi, Hasan B. Albargi</p>
In this study, zinc-oxide (ZnO) nanoparticles (NPs) doped with cobalt (Co) were synthesized using a simple coprecipitation technique. The concentration of Co was varied to investigate its effect on the structural, morphological, optical, and dielectric properties of the NPs. X-ray diffraction (XRD) analysis confirmed the hexagonal wurtzite structure of both undoped and Co-doped ZnO-NPs. Scanning electron microscopy (SEM) was used to examine the morphology of the synthesized NPs, while energy-dispersive X-ray spectroscopy (EDX) was used to verify their purity. The band gap of the NPs was evaluated using UV-visible spectroscopy, which revealed a decrease in the energy gap as the concentration of Co2+ increased in the ZnO matrix. The dielectric constants and AC conductivity of the NPs were measured using an LCR meter. The dielectric constant of the Co-doped ZnO-NPs continuously increased from 4.0 × 10<sup>−9</sup> to 2.25 × 10<sup>−8</sup>, while the dielectric loss decreased from 4.0 × 10<sup>−8</sup> to 1.7 × 10<sup>−7</sup> as the Co content increased from 0.01 to 0.07%. The a.c. conductivity also increased with increasing applied frequency. The findings suggest that the synthesized Co-doped ZnO-NPs possess enhanced dielectric properties and reduced energy gap, making them promising candidates for low-frequency devices such as UV photodetectors, optoelectronics, and spintronics applications. The use of a cost-effective and scalable synthesis method, coupled with detailed material characterization, makes this work significant in the field of nanomaterials and device engineering.Investigating the hard X-ray production via proton spallation on different materials to detect elementsSaeedeh KhezripourMohammadreza RezaieMehdi HassanpourMarzieh HassanpourMohammad Rashed Iqbal FaruqueMayeen Uddin Khandaker10.1371/journal.pone.02882872023-08-18T14:00:00Z2023-08-18T14:00:00Z<p>by Saeedeh Khezripour, Mohammadreza Rezaie, Mehdi Hassanpour, Marzieh Hassanpour, Mohammad Rashed Iqbal Faruque, Mayeen Uddin Khandaker</p>
Various atomic and nuclear methods use hard (high-energy) X-rays to detect elements. The current study aims to investigate the hard X-ray production rate via high-energy proton beam irradiation of various materials. For which, appropriate conditions for producing X-rays were established. The MCNPX code, based on the Monte Carlo method, was used for simulation. Protons with energies up to 1650 MeV were irradiated on various materials such as carbon, lithium, lead, nickel, salt, and soil, where the resulting X-ray spectra were extracted. The production of X-rays in lead was observed to increase 16 times, with the gain reaching 0.18 as the proton energy increases from 100 MeV to 1650 MeV. Comparatively, salt is a good candidate among the lightweight elements to produce X-rays at a low proton energy of 30 MeV with a production gain of 0.03. Therefore, it is suggested to irradiate the NaCl target with 30 MeV proton to produce X-rays in the 0–2 MeV range.Disordered dolomite as an unusual biomineralization product found in the center of a natural <i>Cassis</i> pearlChunhui ZhouShiyun JinZiyin SunArtitaya HomkrajaeElina MyagkayaNanthaporn NilpetployKwanreun Lawanwong10.1371/journal.pone.02842952023-04-26T14:00:00Z2023-04-26T14:00:00Z<p>by Chunhui Zhou, Shiyun Jin, Ziyin Sun, Artitaya Homkrajae, Elina Myagkaya, Nanthaporn Nilpetploy, Kwanreun Lawanwong</p>
Natural pearls are produced without human intervention, mainly due to various irritations from the surrounding environment to their mantle tissues. Pearls usually possess similar mineral compositions to the host shells, which means they are also dominated by aragonite and calcite. In this study, we report a natural pearl from a <i>Cassis</i> species mollusk containing granular central structures. Raman spectroscopy, laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS), energy dispersive X-ray spectroscopy (EDS) coupled with scanning electron microscope (SEM), and X-ray diffraction (XRD) analyses were carried out in order to characterize the mineral composition in the center region of this pearl. Our results showed that this pearl’s center was made of mostly disordered dolomite (Ca<sub>0.53</sub>Mg<sub>0.47</sub>CO<sub>3</sub>) mixing with small amount of aragonite and high magnesium-calcite. To the best of our knowledge, this is the first time disordered dolomite was conclusively identified inside of a natural pearl and such information expanded our knowledge on internal growth structures and formation of natural pearls.Moving beyond MARCONicholas RosaChristopher J. WatkinsJanet Newman10.1371/journal.pone.02831242023-03-24T14:00:00Z2023-03-24T14:00:00Z<p>by Nicholas Rosa, Christopher J. Watkins, Janet Newman</p>
The use of imaging systems in protein crystallisation means that the experimental setups no longer require manual inspection to determine the outcome of the trials. However, it leads to the problem of how best to find images which contain useful information about the crystallisation experiments. The adoption of a deeplearning approach in 2018 enabled a four-class machine classification system of the images to exceed human accuracy for the first time. Underpinning this was the creation of a labelled training set which came from a consortium of several different laboratories. The MARCO classification model does not have the same accuracy on local data as it does on images from the original test set; this can be somewhat mitigated by retraining the ML model and including local images. We have characterized the image data used in the original MARCO model, and performed extensive experiments to identify training settings most likely to enhance the local performance of a MARCO-dataset based ML classification model.Dynamic kernel matching for non-conforming data: A case study of T cell receptor datasetsJared OstmeyerLindsay CowellScott Christley10.1371/journal.pone.02653132023-03-07T14:00:00Z2023-03-07T14:00:00Z<p>by Jared Ostmeyer, Lindsay Cowell, Scott Christley</p>
Most statistical classifiers are designed to find patterns in data where numbers fit into rows and columns, like in a spreadsheet, but many kinds of data do not conform to this structure. To uncover patterns in non-conforming data, we describe an approach for modifying established statistical classifiers to handle non-conforming data, which we call <i>dynamic kernel matching</i> (DKM). As examples of non-conforming data, we consider (i) a dataset of T-cell receptor (TCR) sequences labelled by disease antigen and (ii) a dataset of sequenced TCR repertoires labelled by patient cytomegalovirus (CMV) serostatus, anticipating that both datasets contain signatures for diagnosing disease. We successfully fit statistical classifiers augmented with DKM to both datasets and report the performance on holdout data using standard metrics and metrics allowing for indeterminant diagnoses. Finally, we identify the patterns used by our statistical classifiers to generate predictions and show that these patterns agree with observations from experimental studies.Pterin-based small molecule inhibitor capable of binding to the secondary pocket in the active site of ricin-toxin A chainRyota SaitoMasaru GotoShun KatakuraTaro OhbaRena KawataKazuki NagatsuShoko HigashiKaede KurisuKaori MatsumotoKouta Ohtsuka10.1371/journal.pone.02777702022-12-12T14:00:00Z2022-12-12T14:00:00Z<p>by Ryota Saito, Masaru Goto, Shun Katakura, Taro Ohba, Rena Kawata, Kazuki Nagatsu, Shoko Higashi, Kaede Kurisu, Kaori Matsumoto, Kouta Ohtsuka</p>
The Ricin toxin A chain (RTA), which depurinates an adenine base at a specific region of the ribosome leading to death, has two adjacent specificity pockets in its active site. Based on this structural information, many attempts have been made to develop small-molecule RTA inhibitors that simultaneously block the two pockets. However, no attempt has been successful. In the present study, we synthesized pterin-7-carboxamides with tripeptide pendants and found that one of them interacts with both pockets simultaneously to exhibit good RTA inhibitory activity. X-ray crystallographic analysis of the RTA crystal with the new inhibitor revealed that the conformational change of Tyr80 is an important factor that allows the inhibitors to plug the two pockets simultaneously.Synthesis, characterization, and <i>in vivo</i> safety evaluation of propylated <i>Dioscorea abyssinica</i> starchYonas BrhaneTsige Gebre-MariamAnteneh Belete10.1371/journal.pone.02769652022-11-28T14:00:00Z2022-11-28T14:00:00Z<p>by Yonas Brhane, Tsige Gebre-Mariam, Anteneh Belete</p>
The use of starch, a natural polymeric material, and derivatives thereof is based on its adhesive, thickening, gelling, swelling, and film-forming properties, as well as its ready availability. The objective of this research work is to develop an effective propylated <i>Dioscorea abyssinica</i> starch (PDAS) as a hydrophobic excipient for pharmaceutical applications with a reasonable price. This paper reports on the synthesis, characterization, and <i>in vivo</i> safety evaluation of PDAS. <i>Native Dioscorea abyssinica</i> starch (NDAS) was modified to its propylated form with propionic anhydride and characterized. Crystallinity, morphological structure, thermal behavior, solubility, and safety of PDAS were evaluated using x-ray diffraction, SEM, thermogravimetric, gravimetric, and toxicity studies, respectively. Propionyl content and degree of substitution (DS) of starch increased significantly (p < 0.05) with an increase in reaction time and temperature. Propionyl content and DS of starch increased significantly (p < 0.05) with a decrease in the ratio of starch to pyridine and starch to propionic anhydride in the reaction medium. FTIR spectra of PDAS indicated that hydroxyl groups participated in the propylation reaction. X-ray diffraction results showed that the chemical modification destroyed the crystalline structure of the NDAS. SEM of NDAS showed a rounded shape which became irregular after propylation. Thermogravimetric curves revealed that all the PDAS samples decomposed at higher temperatures than their native counterparts. At higher DS, swelling power and solubility in an aqueous environment significantly (p < 0.05) decreased below that of the native starch. PDAS with high DS, were soluble in organic solvents at room temperature. But PDAS with lower DS didn’t dissolve in all types of organic solvents used. PDAS (DS = 2.842) in distilled water did not produce adverse effects in rats. Based on the results obtained, it can be concluded that PDAS can be considered as a generally safe excipient and fulfills the physicochemical properties of a hydrophobic excipient.Intra-annual fluctuation in morphology and microfibril angle of tracheids revealed by novel microscopy-based imagingYusuke KitaTatsuya AwanoArata YoshinagaJunji Sugiyama10.1371/journal.pone.02776162022-11-15T14:00:00Z2022-11-15T14:00:00Z<p>by Yusuke Kita, Tatsuya Awano, Arata Yoshinaga, Junji Sugiyama</p>
Woody cells, such as tracheids, fibers, vessels, rays etc., have unique structural characteristics such as nano-scale ultrastructure represented by multilayers, microfibril angle (MFA), micro-scale anatomical properties and spatial arrangement. Simultaneous evaluation of the above indices is very important for their adequate quantification and extracting the effects of external stimuli from them. However, it is difficult in general to achieve the above only by traditional methodologies. To overcome the above point, a new methodological framework combining polarization optical microscopy, fluorescence microscopy, and image segmentation is proposed. The framework was tested to a model softwood species, <i>Chamaecyparis obtusa</i> for characterizing intra-annual transition of MFA and tracheid morphology in a radial file unit. According our result, this framework successfully traced the both characteristics tracheid by tracheid and revealed the high correlation (|<i>r</i>| > 0.5) between S<sub>2</sub> microfibril angles and tracheidal morphology (lumen radial diameter, tangential wall thickness and cell wall occupancy). In addition, radial file based evaluation firstly revealed their complex transitional behavior in transition and latewood. The proposed framework has great potential as one of the unique tools to provide detailed insights into heterogeneity of intra and inter-cells in the wide field of view through the simultaneous evaluation of cells’ ultrastructure and morphological properties.Green synthesis of SiO<sub>2</sub> nanoparticles from Rhus coriaria L. extract: Comparison with chemically synthesized SiO<sub>2</sub> nanoparticlesChiya Yousef RahimzadehAzeez Abdullah BarzinjyAhmed Salih MohammedSamir Mustafa Hamad10.1371/journal.pone.02681842022-08-05T14:00:00Z2022-08-05T14:00:00Z<p>by Chiya Yousef Rahimzadeh, Azeez Abdullah Barzinjy, Ahmed Salih Mohammed, Samir Mustafa Hamad</p>
The usage of the green synthesis method to produce nanoparticles (NPs) has received great acceptance among the scientific community in recent years. This, perhaps, is owing to its eco-friendliness and the utilization of non-toxic materials during the synthesizing process. The green synthesis approach also supplies a reducing and a capping agent, which increases the stability of the NPs through the available phytochemicals in the plant extractions. The present study describes a green synthesis method to produce nano-silica (SiO<sub>2</sub>) NPs utilizing Rhus coriaria L. extract and sodium metasilicate (Na<sub>2</sub>SiO<sub>3</sub>.5H<sub>2</sub>O) under reflux conditions. Sodium hydroxide (NaOH) is added to the mixture to control the pH of the solution. Then, the obtained NPs have been compared with the chemically synthesized SiO<sub>2</sub> NPs. The structure, thermal, and morphological properties of the SiO<sub>2</sub> NPs, both green synthesized and chemically synthesized, were characterized using Fourier-transform infrared spectroscopy (FTIR), Ultraviolet-Visible Spectroscopy (UV-Vis), X-ray diffraction (XRD), and Field Emission Scanning Electron Microscopy (FESEM). Also, the elemental compassion distribution was studied by energy-dispersive X-ray spectroscopy (EDX). In addition, the zeta potential, dynamic light scatter (DLS), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) was used to study the stability, thermal properties, and surface area of the SiO<sub>2</sub> NPs. The overall results revealed that the green synthesis of SiO<sub>2</sub> NPs outperforms chemically synthesized SiO<sub>2</sub> NPs. This is expected since the green synthesis method provides higher stability, enhanced thermal properties, and a high surface area through the available phytochemicals in the Rhus coriaria L. extract.Structural and biophysical properties of FopA, a major outer membrane protein of <i>Francisella tularensis</i>Nirupa NagaratnamJose M. Martin-GarciaJay-How YangMatthew R. GoodeGihan KetawalaFelicia M. CraciunescuJames D. ZookManashi SonowalDewight WilliamsThomas D. GrantRaimund FrommeDebra T. HansenPetra Fromme10.1371/journal.pone.02673702022-08-01T14:00:00Z2022-08-01T14:00:00Z<p>by Nirupa Nagaratnam, Jose M. Martin-Garcia, Jay-How Yang, Matthew R. Goode, Gihan Ketawala, Felicia M. Craciunescu, James D. Zook, Manashi Sonowal, Dewight Williams, Thomas D. Grant, Raimund Fromme, Debra T. Hansen, Petra Fromme</p>
<i>Francisella tularensis</i> is an extremely infectious pathogen and a category A bioterrorism agent. It causes the highly contagious zoonosis, Tularemia. Currently, FDA approved vaccines against tularemia are unavailable. <i>F</i>. <i>tularensis</i> outer membrane protein A (FopA) is a well-studied virulence determinant and protective antigen against tularemia. It is a major outer membrane protein (Omp) of <i>F</i>. <i>tularensis</i>. However, FopA-based therapeutic intervention is hindered due to lack of complete structural information for membrane localized mature FopA. In our study, we established recombinant expression, monodisperse purification, crystallization and X-ray diffraction (~6.5 Å) of membrane localized mature FopA. Further, we performed bioinformatics and biophysical experiments to unveil its structural organization in the outer membrane. FopA consists of 393 amino acids and has less than 40% sequence identity to known bacterial Omps. Using comprehensive sequence alignments and structure predictions together with existing partial structural information, we propose a two-domain organization for FopA. Circular dichroism spectroscopy and heat modifiability assay confirmed FopA has a β-barrel domain consistent with alphafold2’s prediction of an eight stranded β-barrel at the N-terminus. Small angle X-ray scattering (SAXS) and native-polyacrylamide gel electrophoresis revealed FopA purified in detergent micelles is predominantly dimeric. Molecular density derived from SAXS at 31 Å shows putative dimeric N-terminal β-barrels surrounded by detergent corona and connected to C-terminal domains via flexible linker. Disorder analysis predicts N- and C-terminal domains are interspersed by a long intrinsically disordered region and alphafold2 predicts this region to be largely unstructured. Taken together, we propose a dimeric, two-domain organization of FopA in the outer membrane: the N-terminal β-barrel is membrane embedded, provides dimerization interface and tethers to membrane extrinsic C-terminal domain via long flexible linker. Structure determination of membrane localized mature FopA is essential to understand its role in pathogenesis and develop anti-tularemia therapeutics. Our results pave the way towards it.Progress in affinity ligand-functionalized bacterial magnetosome nanoparticles for bio-immunomagnetic separation of HBsAg proteinLeila Hatami Giklou JajanSeyed Nezamedin HosseiniMohsen AbolhassaniMasoud Ghorbani10.1371/journal.pone.02672062022-07-25T14:00:00Z2022-07-25T14:00:00Z<p>by Leila Hatami Giklou Jajan, Seyed Nezamedin Hosseini, Mohsen Abolhassani, Masoud Ghorbani</p>
Efficient Bio-immunomagnetic separation (BIMS) of recombinant hepatitis B surface antigen (rHBsAg) with high binding capacity was studied using affinity ligand immobilized bacterial magnetosome nanoparticles (Magnetospirillum gryphiswaldense strain MSR-1 bacteria) as an immunomagnetic sorbent. Our results showed immunomagnetic adsorption, acted by affinity interactions with the immobilized monoclonal antibody, offered higher antigen adsorption and desorption capacities as compared with the commercially available immunoaffinity sorbents. Four different ligand densities of the Hep-1 monoclonal antibody were examined during covalent immobilization on Pyridyl Disulfide-functionalized magnetosome nanoparticles for HBsAg immunomagnetic separation. The average of adsorption capacity was measured as 3 mg/ml in optimized immunomagnetic sorbent (1.056 mg rHBsAg/ml immunomagneticsorbent/5.5 mg of total purified protein) and 5mg/ml in immunoaffinity sorbent (0.876 mg rHBsAg/ml immunosorbent/5.5 mg total purified protein during 8 runs. Immunomagnetic sorbent demonstrated ligand leakage levels below 3 ng Mab/Ag rHBsAg during 12 consecutive cycles of immunomagnetic separation (IMS). The results suggest that an immunomagnetic sorbent with a lower ligand density (LD = 3 mg Mab/ml matrix) could be the best substitute for the immunosorbent used in affinity purification of r-HBsAg there are significant differences in the ligand density (98.59% (p-value = 0.0182)), adsorption capacity (97.051% (p-value = 0.01834)), desorption capacity (96.06% (p-value = 0.036)) and recovery (98.97% (p-value = 0.0231)). This study indicates that the immunosorbent approach reduces the cost of purification of Hep-1 protein up to 50% as compared with 5 mg Mab/ml immunoaffinity sorbent, which is currently used in large-scale production. As well, these results demonstrate that bacterial magnetosome nanoparticles (BMs) represent a promising alternative product for the economical and efficient immobilization of proteins and the immunomagnetic separation of Biomolecules, promoting innovation in downstream processing.Antioxidant properties of bee propolis and an important component, galangin, described by X-ray crystal structure, DFT-D and hydrodynamic voltammetryFrancesco CarusoMolly BerinatoMelissa HernandezStuart BelliChristopher SmartMiriam Rossi10.1371/journal.pone.02676242022-05-18T14:00:00Z2022-05-18T14:00:00Z<p>by Francesco Caruso, Molly Berinato, Melissa Hernandez, Stuart Belli, Christopher Smart, Miriam Rossi</p>
Propolis is produced by honeybees and used to seal their hives for defensive purposes and has been used in ethnopharmacology since ancient times. It is a lipophilic material containing a large collection of naturally produced plant organic molecules, including flavonoids. The flavonoid galangin is consistently found in propolis, independent of the hive geographical location and its X-ray crystal and molecular structure is reported. The antioxidant scavenging of superoxide by galangin and propolis is here presented. Using a cyclic voltammetry technique developed in our lab, we show that galangin is an excellent scavenger of the superoxide radical, perhaps even better than quercetin. Our results show that galangin displays a Superoxide Dismutase (SOD) function. This is described experimentally and theoretically (DFT). Two modes of scavenging superoxide are seen for galangin: (1) superoxide radical extraction of H atom from the hydroxyl moieties located in position 3 and 5 of galangin, which are also associated with proton incorporation defining the SOD action; (2) π-π interaction among several superoxide radicals and the galangin polyphenol ring that evolve towards release of O<sub>2</sub> and H<sub>2</sub>O<sub>2</sub>. We describe these two actions separately as their relative sequence, and/or combination, cannot be defined; all these processes are thermodynamically spontaneous, or subjected to mild barriers.