Isoelectric Point Research Articles

Efficient removal of congo red and cytotoxicity evaluation of biosorbents prepared from chitosan-added watermelon pulp

The development of environmentally friendly adsorbents has become increasingly important for treating waste generated by the growing global industry. In this study, new biosorbents were synthesized from an all-natural chitosan and watermelon pulp for the treatment of congo red textile dye from water. Biosorbents were prepared by lyophilizing chitosan-added watermelon pulp (AC-WPC). The prepared biosorbents were characterized by BET, SEM, Zeta Potential and FT-IR analysews. Accordingly, the BET surface area of AC-WPC was 120.92 m2/g. SEM analysis showed that the structures were porous and the results were consistent with the BET analysis. FT-IR analysis confirmed the chemical structures. The isoelectric points of the biosorbents were determined by zeta potential analysis. The AC-WPC biosorbent demonstrated 86% cell viability with cytotoxicity testing. For this reason, it was determined that the AC-WPC biosorbents produced does not cause any serious damage to the cell. Following this, adsorption study of congo red textile dye in water was carried out with these biosorbents. Langmuir and Freundlich isotherms were studied in adsorption experiments, and it was found that the Freundlich isotherms were compatible. Pseudo first and second kinetic models were also studied and found to be compatible with Pseudo Second Kinetic Model. The highest adsorption capacity was observed at 100 mg/l congo red concentration with 98.02% removal and 490.1 mg/g adsorption capacity using AC-WPC. It is thought that these results will potentially contribute to the literature on the removal of textile dyes or other pollutants using chitosan-added watermelon pulp.

Zein-cyclodextrin complex used to prepare high internal phase pickering emulsions with various oil phases

Biobased solid particles for stabilizing high internal phase emulsions (HIPEs) are widely used in food and cosmetics industries. This study report a kind of zein-cyclodextrin complex particles which could HIPEs with various oil phases (log P values: 1.14–9.26), showcasing their wide applicability across different oil types. This versatility due to the slight differences (6–8°) in the three-phase contact angles for different oils. Furthermore, the complex particles showed a marked improvement in emulsification performance, as evidenced by their significantly higher diffusion rates (7–15 times faster) and reorientation speeds (2–5 times faster) at the oil-water interface. Moreover, the emulsions prepared were stable across a broad pH range (3–9), successfully addressing the common stability challenges associated with protein-based emulsifiers near their isoelectric points. Therefore, these complex particles have great potential in cosmetics, waste oil treatment and food field, such as multifunctional 3D bioprinting ink.

Influence of pH fractionation and salt on Bambara protein–gum arabic interaction and insoluble complex formation

Proteins exhibit remarkable interaction with polysaccharides to form complexes with novel functionality. Nevertheless, the formation of insoluble complexes close to the protein isoelectric point (pI) results in protein–protein interference, low coacervates yield, and limited application in acidified food systems. Hence, pH fractionation with salt was used to extract Bambara groundnut protein to induce a shift in optimum pH (pHopt) of insoluble complexes formed with gum arabic, ultimately improving protein and coacervates yields. Turbidimetric analyses were employed to monitor the interaction between Bambara groundnut protein and gum arabic. Protein isolates from optimised fractionation conditions and insoluble complexes were characterised. The most effective fractionation condition was achieved at pH 2.95, 0.28 M NaCl, producing a substantial pHopt shift to 3.4. This shift was associated with the formation of spherical microparticle complexes and an impressive 70% coacervate yield. Changes in patterns of protein–gum arabic interaction were associated with an increased content of β-sheet, enrichment of legumin subunits, and basic amino acids of the isolate. This approach successfully shifted the formation of insoluble complexes towards a high-acid pH environment, notably away from the pI. Findings from this study create a prospect for future utilisation of pulse grain protein-gum arabic complexes in acidic beverage development.

Insight into the structure-activity relationship of thermal hysteresis activity of cod collagen peptides through peptidomics and bioinformatics approaches

To elucidate the correlation between variations in thermal hysteresis activity (THA) and the physicochemical properties and structure, antifreeze peptides (AFPs) of isolated fractions (CCP-1 and CCP-2) were characterized on based peptidomics and bioinformatics. The results revealed a positive correlation between the THA of cod collagen antifreeze peptide (CCAFP) and peptide chain length, isoelectric point, and hydrophobic amino acid content. Notably, the THA of CCP-1, which has higher alkaline amino acid content, was 2.60 °C at a concentration of 10 mg/mL, significantly higher than CCP (1.90 °C) and CCP-2 (2.27 °C). Glycine, proline, and valine were the vital amino acids to the formation of hydrogen bonds. Conversely, aspartic and glutamic acids at terminal regions of AFPs tended to introduce kinks in their structures. This distortion reduced binding sites for ice crystals, thereby decreasing their THA, providing a theory for understanding the physicochemical properties and structure of AFPs that influence their THA.

Investigating the antifungal potential of genetically modified hybrid chitinase enzymes derived from Bacillus subtilis and Serratia marcescens.

Chitinases are glycosyl hydrolase enzymes that break down chitin, an integral component of fungal cell walls. Bacteria such as Bacillus subtilis and Serratia marcescens produce chitinases with antifungal properties. In this study, we aimed to generate hybrid chitinase enzymes with enhanced antifungal activity by combining functional domains from native chitinases produced by B. subtilis and S. marcescens. Chitinase genes were cloned from both bacteria and fused together using overlap extension PCR. The hybrid constructs were expressed in E. coli and the recombinant enzymes purified. Gel electrophoresis and computational analysis confirmed the molecular weights and isoelectric points of the hybrid chitinases were intermediate between the parental enzymes. Antifungal assays demonstrated that the hybrid chitinases inhibited growth of the fungus Fusarium oxysporum significantly more than the native enzymes and also showed fungicidal activity against Candida albicans, Alternaria solani, and Rhizoctonia solani. The results indicate that hybrid bacterial chitinases are a promising approach to engineer novel antifungal proteins. This study provides insight into structure-function relationships of chitinases and strategies for generating biotherapeutics with enhanced bioactive properties. These hybrid chitinases result in a more potent and versatile antifungal agent.

Impact of Indole Inclusion in the Design of Multi-Tactical Metal-Binding Tetra-Aza Macrocycles that Target the Molecular Features of Neurodegeneration.

Numerous small molecules have been studied for their ability to counteract oxidative stress, a key contributor to neurodegenerative diseases such as Alzheimer's. Despite these efforts, the pharmacological properties and structure-activity relationships of these compounds remain insufficiently understood, yet they are critical in evaluating a drug molecule's therapeutic potential. A modified tetra-aza macrocycle has demonstrated strong antioxidant activity through various mechanisms; however, its limited permeability presents challenges for advanced formulation studies. To enhance permeability while preserving the beneficial reactivity of the parent molecule, two synthetic modifications involving indole functionality were explored and compared to modifications using methyl groups alone. New synthetic strategies were developed to produce the indole-containing molecules, which were characterized by 1D/2D NMR techniques. Isoelectric points, metal binding, and radical scavenging activity were determined to validate that the reactivity of the parent molecules was retained. The permeability of all molecules explored was improved. Protection against oxidative stress through activation of the Nrf2 pathway was demonstrated for molecules containing indoles in cellular models by measuring ROS levels upon treatment and mRNA levels of HO-1 and Nrf2. In contrast, no protection or Nrf2 activation was observed with the methylation of the O- or N atom. These results suggest that while alkylation improves permeability overall, concomitant antioxidant protection and positive permeability are achieved with the indole congeners alone.

Mechanistic Insights into the Removal of Surfactant-Like Contaminants on Mesoporous Polydopamine Nanospheres from Complex Wastewater Matrices.

The detrimental environmental effects of surfactant-like contaminants (SLCs) with distinctive amphiphilic structures have garnered significant attention, particularly since perfluorooctanesulfonate was classified as a persistent organic pollutant. Despite the numerous absorbents developed for SLCs removal, the underlying interaction mechanisms remain speculative and lack experimental validation. To address this research gap, we elucidate the mechanistic insights into the selective removal of SLCs using mesoporous polydopamine nanospheres (MPDA) fabricated via a novel soft-template method. We employed low-field nuclear magnetic resonance to quantitatively characterize the hydrophilicity of the absorbents using water molecules as probes. The results demonstrated that MPDA with uniform mesopores exhibited a remarkable threefold enhancement in SLCs' adsorption capacity compared to conventional polydopamine particles via intraparticle diffusion. We further demonstrated the dominant effects of electrostatic and hydrophobic interactions on the selective removal of SLCs with MPDA by regulating the isoelectric pH value and performing a comparative analysis. The mechanism-inspired SLC-removal strategy achieved an average removal rate of 76.3% from highly contaminated wastewater. Our findings offer new avenues for applying MPDA as an efficient adsorbent and provide innovative and mechanistic insights for targeted SLC removal in complex wastewater matrices.

Structural Prediction and Antigenic Analysis of ROP18, MIC4, and SAG1 Proteins to Improve Vaccine Design against Toxoplasma gondii: An In silico Approach.

Toxoplasmosis is a cosmopolitan infectious disease in warm-blooded mammals that poses a serious worldwide threat due to the lack of effective medications and vaccines. The purpose of this study was to design a multi-epitope vaccine using several bioinfor-matics approaches against the antigens of Toxoplasma gondii (T. gondii). Three proteins of T. gondii, including ROP18, MIC4, and SAG1, were analyzed to predict the most dominant B- and T-cell epitopes. Finally, we designed a chimeric immunogen RMS (ROP18, MIC4, and SAG1) using some domains of ROP18 (N377-E546), MIC4 (D302-G471), and SAG1 (T130-L299) linked by rigid linker A (EAAAK) A. Physicochemical prop-erties, secondary and tertiary structures, antigenicity, and allergenicity of RMS were predicted utilizing immunoinformatic tools and servers. RMS protein had 545 amino acids with a molecular weight (MW) of 58,833.46 Da and a theoretical isoelectric point (IP) of 6.47. The secondary structure of RMS protein con-tained 21.28% alpha-helix, 24.59% extended strand, and 54.13% random coil. In addition, eval-uation of antigenicity and allergenicity showed the protein to be an immunogen and non-aller-gen. The results of the Ramachandran plot indicated that 76.4%, 12.9%, and 10.7% of amino acid residues were incorporated in the favored, allowed, and outlier regions, respectively. ΔG of the best-predicted mRNA secondary structure was -593.80 kcal/mol, which indicated that a stable loop was not formed at the 5' end. Finally, the accuracy and precision of the in silico analysis must be confirmed by successful heterologous expression and experimental studies.

Bioinformatics Analysis of the Panax ginseng Cyclophilin Gene and Its Anti-Phytophthora cactorum Activity.

In this paper, Panax ginseng cyclophilin (PgCyP) was successfully obtained through a genetic engineering technique. A bioinformatics method was used to analyze the physicochemical properties and structure of PgCyP. The results showed that PgCyP belongs to the cyclophilin gene family. The protein encoded by the PgCyP gene contains the active site of PPIase (R62, F67, and H133) and a binding site for cyclosporine A (W128). The relative molecular weight of PgCyP is 187.11 bp; its theoretical isoelectric point is 7.67, and it encodes 174 amino acids. The promoter region of PgCyP mainly contains the low-temperature environmental stress response (LTR) element, abscisic acid-responsive cis-acting element (ABRE), and light-responsive cis-acting element (G-Box). PgCyP includes a total of nine phosphorylation sites, comprising four serine phosphorylation sites, three threonine phosphorylation sites, and two tyrosine phosphorylation sites. PgCyP was recombined and expressed in vitro, and its recombinant expression was investigated. Furthermore, it was found that the recombinant PgCyP protein could effectively inhibit the germination of Phytophthora cactorum spores and the normal growth of Phytophthora cactorum mycelia in vitro. Further experiments on the roots of susceptible Arabidopsis thaliana showed that the PgCyP protein could improve the resistance of arabidopsis to Phytophthora cactorum. The findings of this study provide a basis for the use of the PgCyP protein as a new type of green biopesticide.

Enhanced removal of tetracycline by vitamin C-modified cow manure biochar in water

Vitamin C (VC), due to its chemical properties, can provide more oxygen-containing functional groups such as hydroxyl groups for biochar (BC), which promotes the adsorption of tetracycline on biochar. Therefore, in this study, cow dung biochar (CDBC) was modified with VC and VC-modified CDBC (CDBC-VC) was synthesized. The modified biochar was characterized and related factors, adsorption kinetics, isotherms and adsorption mechanisms were investigated. Adsorption kinetics indicate a fast rate of adsorption. The adsorption isotherms showed that the maximum adsorption capacity was 31.72 mg/g (CDBC) and 50.90 mg/g (CDBC-VC), respectively, and the adsorption process was inhomogeneous with multiple molecular layers and the adsorbent has a higher affinity. Mechanistic studies showed that hydrogen bonding interactions, π-π electron donor-acceptor interactions, hydrophobic interactions, and electrostatic interactions were the key to the adsorption process. The analysis of adsorbent regeneration showed that CDBC-VC had good adsorption performance. CDBC and CDBC-VC showed the best performance in simulated industrial wastewater with removal rates of 78.81% and 93.69%. The adsorption mechanism was comprehensively analyzed using six machine learning models. The extreme gradient boosting model gave the best fit. Analysis of the weights of the input variables for predicting adsorption efficiency showed that the ratio of initial TC concentration to BC dosage (29.8%), specific surface area (23%), isoelectric point (8.8%), and ash content (7.7%) had a significant effect on the predicted results.

Designing mixed cationic/anionic supports to covalently immobilize/stabilize enzymes with high isoelectric point by enzyme adsorption and support-enzyme glutaraldehyde crosslinking

Ficin fully immobilized on Asp-agarose beads at pH 7 but not on an aminated support. This made enzyme adsorption plus glutaraldehyde modification non-viable for this enzyme. Modifying glyoxyl-agarose beads with mixtures of Asp and 1,6-hexamethylenediamine (HA) at different ratios, mixed anion/cation exchanger supports were built. Only if HA greatly exceed Asp in the support, immobilization did not work. While only using the Asp-agarose support immobilized enzyme molecules were only ionically adsorbed after glutaraldehyde treatment (visualized in SDS-PAGE analysis), the mixed supports gave covalent immobilization. The glutaraldehyde modification of these biocatalysts permitted to establish covalent bonds with the support, and this was more effective when using higher amounts of HA in the support. When around 60 % of the groups in the support were HA, the treatment with glutaraldehyde fully suppressed enzyme release from the support after boiling in SDS. The glutaraldehyde treated biocatalysts were more stable than just the adsorbed enzymes or the enzyme adsorbed only on Asp supports and then treated with glutaraldehyde (the optimal biocatalyst retained 90 % of the initial activity while the just adsorbed ficin retained 50 % of the initial activity). This strategy can be utilized to immobilize other proteins with high isoelectric points following this immobilization strategy.

Genome-Wide Identification of the bHLH Gene Family in Rhododendron delavayi and Its Expression Analysis in Different Floral Tissues.

The bHLH genes play a crucial role in plant growth, development, and stress responses. However, there is currently limited research on bHLH genes in the important horticultural plant Rhododendron delavayi Franch. In this study, we conducted a comprehensive genome-wide identification and in-depth analysis of the bHLH gene family in R. delavayi using bioinformatics approaches. A total of 145 bHLH family members were identified, encoding proteins ranging from 98 to 3300 amino acids in length, with molecular weights ranging from 11.44 to 370.51 kDa and isoelectric points ranging from 4.22 to 10.80. These 145 bHLH genes were unevenly distributed across 13 chromosomes, with three bHLH genes located on contig 52. Chromosome 8 contained the highest number of bHLH family members with 19 genes, while chromosomes 9 and 13 had the lowest, with 7 genes each. Phylogenetic analysis revealed a close evolutionary relationship between bHLH genes in R. delavayi and Arabidopsis thaliana. Subcellular localization analysis indicated that most bHLH genes were located in the nucleus. Promoter analysis of R. delavayi bHLH genes revealed the presence of various cis-regulatory elements associated with light responses, methyl jasmonate responses, low-temperature responses, and coenzyme responses, suggesting that bHLH genes are involved in multiple biological processes in R. delavayi. Through transcriptome analysis, we identified three key functional genes-Rhdel02G0041700, Rhdel03G0013600, and Rhdel03G0341200-that may regulate flower color in R. delavayi. In conclusion, our study comprehensively identified and analyzed the bHLH gene family in R. delavayi and identified three bHLH genes related to flower color, providing a foundation for molecular biology research and breeding in R. delavayi.

Enhanced production, artificial intelligence optimized three-phase partitioning extraction, and in silico characterization of extracellular neutral Bacillus cereus proteinase

The present study applied atmospheric and room temperature plasma (ARTP) mutagenesis to improve Bacillus cereus strain for neutral proteinase production. The selected improved stable strain, Phe−Tyr-ARTP-60-E demonstrated a 2.88-fold enhanced proteinase yield and 2.81-fold enhanced proteinase activity with shortened fermentation time. An artificial neural network-embedded genetic algorithm (ANN-GA) was employed to optimize the enzyme's three-phase partitioning (TPP) recovery using Python software. The optimized solution of the hybrid model recommended 38.05% wv−1 (NH4)2SO4, 1.0:2.0 crude extract/tert-butanol ratio, pH 5.84 at 23.4 °C, for the exclusive partitioning of proteinase in the intermediate phase, with 202% recovery, 13-fold purity with specific activity of 922 Umg−1. Sensitivity analysis of the model revealed that enzyme recovery was most sensitive to crude extract/tert-butanol ratio with total sensitivity (ST) of 0.253 while purification factor was most sensitive to pH with an ST of 0.444. In silico analysis using Expasy ProtParam tool revealed that mutant proteinase had 3 amino acid substitutions; Val-to-Cys; Val-to-His and Ile-to-Lys, at positions 152, 288, and 292, respectively, and 39.2 kDa molecular weight, 6.42 isoelectric point, and 33.35 instability index. The 3-Dimensional structure of the enzyme predicted by ModWeb v r273 Server revealed 39% sequence identity with Pseudoalteromonas lipolytica thermolysin. The macromolecule increased transmittance in lysozyme-coated contact lenses by 99.6% in 45 min. We conclude that ARTP mutagenesis and ANN-GA optimized TPP are effective and efficient recalcitrant strain improvement and product recovery methods, respectively. Further genetic tools and analysis of the neutral proteinase-producing gene may be required for increased improvement toward sustainable application.

Buffer Screening of Protein Formulations Using a Coarse-Grained Protocol Based on Medicinal Chemistry Interactions.

In drug and vaccine development, the designed protein formulation should be highly stable against the temperature, pH, buffer, excipients, and other environmental settings. Similarly, in a sensing unit, one needs to know how strongly two biomolecules bind to guide the design of the biorecognition unit accordingly. Typically, the community performs a series of experiments to thoroughly examine the parameter space, the so-called design-of-experiment (DoE) method, to identify the optimal formulation conditions. Unfortunately, extensive physical testing entails high costs, repeatability issues, and a lack of in-depth knowledge of the underlying mechanisms that affect the final outcome. To address these challenges, we developed a physics-based simulation protocol for buffer screening of protein formulations. We are introducing a coarse-grained molecular simulation protocol that consists of six different interactions. The so-called medicinal chemistry interactions (electrostatics, hydrophobicity, hydrogen bonding propensity, disulfide bonding, and water-water) are based on the physical nature of the protein's amino acid and the partitioning/polarity of any other chemical constituent. The protocol is applied in immunoglobulin-based monoclonal antibodies. We have analyzed the protein behavior as a function of acidity (pH) to discover the isoelectric point by solving the Poisson-Boltzmann equation in a mesoscale grid. To identify the conditions under which the protein oligomerizes in a given buffer, pH, temperature, and ionic strength, we are performing dissipative particle dynamics (DPD) simulations. The protocol allows researchers to reach the high time/space scales required to study protein formulations in their full complexity. Combined with the disruptive protein folding artificial intelligence (AI) algorithms that have been recently developed, the protocol creates a powerful digital framework for cultivating advanced pharmaceutical and biological applications.

Microencapsulation of a green microalga (Chlorella vulgaris) by complex coacervation for its valuation as a feasible ingredient in pear snacks

The nutritional and bioactivity values of Chlorella vulgaris make this green microalga a potential functional food ingredient. However, its unpleasant taste and smell, as well as dark green color, have been considered restrictive for its consumers' acceptability. Here, it was hypothesized that complex coacervation can be used to produce microcapsules able to mitigate the sensory weaknesses of C. vulgaris in think pear snacks, while ensuring their acceptance and intention to buy. For this, two proteins with similar isoelectric points were used, the pea protein isolate (PPI) and the bovine serum albumin (BSA), while the partially-sulfated carrageenan (C) was the selected polysaccharide to encapsulate C. vulgaris (6 % w/w), at pH 3. Higher encapsulation yield (79 %) and efficiency (75 %) were obtained for PPI/C coacervates due to these polymers' higher electrostatic interaction at pH 3, contrasting with the higher repulsion promoted by some negatively charged BSA amino acids. Despite this, both microcapsules exhibited an amorphous structure and low water activity (aw around 0.3). However, PPI/C microcapsules had significantly lower moisture and water solubility (11 % and 57 %, respectively), as well as continuous shells. Moreover, PPI/C avoided the early release of C. vulgaris compounds at gastric conditions ensuring its later release in the intestinal tract. When incorporated into think pear snacks, the higher sensory scores and buying intention were obtained for snacks with PPI/C microcapsules containing C. vulgaris. Therefore, complex coacervation, particularly of PPI/C, allowed to mitigate non-valued microalga sensory attributes contributing for the future acceptance and consumption of algae-based food products.

Structure and Function of Fermentation-Derived Bovine Lactoferrin Produced from Komagataella phaffii

Bovine lactoferrin (bLf) confers significant functional benefits for human health, but low concentrations in milk and high cost of commercial production limit availability and thus product application. Precision fermentation offers a solution to increase availability of biosimilar recombinant bLf (rbLf) thereby opening new opportunities for this high-value ingredient. To comply with regulatory requirements, we aimed to establish that rbLf from <i>K. phaffii</i> is substantially similar to native bLf in structure and key functions. Intact mass analysis showed a molecular weight of 84 kDa for rbLf, comparable to 82-83 kDa of bLf. LC-MS <i>N</i>-linked glycan profiling revealed predominantly high-mannose-based glycans on rbLf, similar to ~50% of bLf glycans. The isoelectric point and core amino acid sequence of rbLf and bLf are identical. rbLf retains the functional ability to bind and release iron, bind to intestinal Lf receptors, increase epithelial cell growth (>120% of control, P < 0.0001), reduce EPEC growth (>50% reduction, P < 0.0001), bind LPS (+4 fold, P < 0.001) and antagonize LPS-induced TLR4 activity (>40% reduction, P < 0.0001). These results demonstrate similarity of rbLf in structure and function to native bLf, supporting the effective application for expanded market opportunities for infant and adult health.

Surface and electrochemical characteristics of S-scheme nanoheterostructured photocatalysts of AgIO3/Cu2SnS3 with enhanced solar energy driven photocatalytic activity

Wastewater treatment is regarded as one of the most challenges to overcome worldwide water threats. As a result, great efforts were devoted to find alterative solutions to maximize the usage of wastewater in industries or agriculture which consumes 70 % of water resources. Interestingly, the utilization of solar energy as a renewable, green and costless energy source is the ideal sustainable solution for wastewater treatment. In this context, Chalcogenides based nanoheterostructures such as AgIO3/Cu2SnS3 were prepared via simple, cost-effective and large-scale methods then utilized as visible light active photocatalysts for wastewater treatment. Scanning electron microscopy (SEM), X-ray powder diffraction (XRD), N2 sorpometry (BET), X-ray photoelectron spectroscopy (XPS), ultraviolet visible light spectrophotometry (UV–vis), and Isoelectric point (pHiep) were utilized to investigate the characteristics of nanoheterostructures. The produced nanoheterostructures were evaluated as photocatalysts for amoxicillin photodegradation using solar energy. The AgIO3/Cu2SnS3 (25ACS) demonstrated a superior photodegradation efficiency (93.5 %) after 60 min. Mot-Schottky plots and trapping experiments were carried out to have an extensive insight of the photodegradation mechanism.

Repairment of carbon steel oxide scale using Ce³⁺ and Ni²⁺ doped sol-gel technique

Corrosion of carbon steel rebars in concrete structures significantly compromises their safety, reliability, and environmental performance. This work focuses on enhancing rebar corrosion resistance by repairing the defects of oxide scale. Here, sol-gel was employed as a carrier, by which Ce3+ and Ni2+ were transferred to the oxide scale defects based on the isoelectric point theory, and deposited at these defects with the pH variation as temperature. The repaired oxide scale showed enhanced uniform elemental distribution and improved electrochemical properties, maintaining integrity even under prolonged exposure to Cl−-rich environments. Notably, the impedance modulus at 0.01 Hz (|Z | 0.01Hz) of treated samples was six times higher than untreated ones, indicating superior performance against high electric fields. This strategy shows great potential for enhancing the durability of concrete structures.

PH-induced interface protein structure changes to adjust the stability of tilapia protein isolate emulsion prepared by high-pressure homogenization

The pH is a crucial external factor affecting the structure and emulsification characteristics of proteins. The current study aimed to reveal the correlation between the secondary structure changes and tilapia protein isolate (TPI) emulsion stability under different pH (3.0–10.0) prepared by high-pressure homogenization. The results showed that TPI with significantly increased solubility and emulsifying properties when the pH keep away from the isoelectric point (pH 5.0). Meanwhile, TPI emulsions presented significantly enhanced stability (with decreased particle size, increased zeta potential, creaming index close to 0, and uniform dispersion of droplets) at pH 3.0 and 10.0. Interface-adsorbed protein mainly consists of a myosin-heavy chain and actin, and the secondary structure was significantly influenced by pH and high-pressure homogenization. The α-helix will be transformed into β-sheet and β-turn when pH is closer to pH 5.0. However, the high-pressure homogenization induced α-helix conversion to β-sheet. The correlation analysis revealed that emulsion stability is positively correlated with α-helix and negatively correlated with β-sheet. This work provides a deep insight into the correlation between secondary structure changes and the stability of TPI emulsion as affected by pH to offer an alternative way to enhance TPI emulsion stability.

Proteomic analysis of two novel peptides from the Odontobuthus doriae scorpion venom

The venom of the Odontobuthus doriae scorpion, prevalent in East Asia and Iran, has not been fully characterized. This study provides the first proteomic profile of O. doriae venom to explore its potential as a medical. 2D-PAGE analysis revealed 96 protein spots with isoelectric points from 3 to 9 and molecular weights between 6.6 to 205 kDa. Fourteen toxin fractions were isolated via HPLC, and SDS-PAGE showed seven protein bands ranging from 3.8 to 182 kDa. MALDI-TOF MS identified Peptide 1 and Peptide 2, resembling Hemoglobin beta-2 chain and Chaperonin HSP60 and suggest potential therapeutic applications for P1 and P2.