Bovine Protein Research Articles

Macrophage-Immunomodulatory Actions of Bovine Whey Protein Isolate, Glycomacropeptide, and Their In Vitro and In Vivo Digests

Whey protein isolate (WPI) consists of an array of proteins and peptides obtained as a byproduct of the cheesemaking process. Research suggests that WPI, along with its peptides such as glycomacropeptide (GMP), possesses immunomodulatory properties. These properties hold potential for alleviating the adverse effects of inflammatory conditions such as inflammatory bowel disease. Although promising, the immunoregulatory properties of the digested forms of WPI and GMP—those most likely to interact with the gut immune system—remain under-investigated. To address this knowledge gap, the current study examined the effects of in vitro-digested WPI and GMP, in vivo-digested WPI, and undigested WPI and GMP on the secretion of pro-inflammatory cytokines (TNF-α and IL-1β) in lipopolysaccharide-stimulated macrophage-like cells. Our results indicate that digested WPI and GMP reduced the expression of TNF-α and IL-1β, two pro-inflammatory cytokines. Whole WPI had no effect on TNF-α but reduced IL-1β levels. In contrast, in vivo-digested WPI reduced TNF-α but increased IL-1β. Undigested GMP, on the other hand, increased the secretion of both cytokines. These results demonstrate that digestion greatly modifies the effects of WPI and GMP on macrophages and suggest that digested WPI and GMP could help mitigate gastrointestinal inflammation. Further clinical studies are necessary to determine the biological relevance of WPI and GMP digestion products within the gut and their capacity to influence gut inflammation.

Bovine nucleoprotein transitions genes and protein abundance as valuable markers of sperm motility and the correlation with fertility

Bovine nucleoprotein transitions (TNPs), specifically TNP1 and TNP2, are essential molecules in sperm nucleus rich in arginine and lysine. These molecules act in the phase between histone expulsion and before incorporation of protamine in the spermatid nucleus. Therefore, this study aimed to analyze genes and protein abundance of TNP1 and TNP2 in sperm to determine the potential as motility markers and correlation with fertility in the field. An objective evaluation method, CASA-Sperm Vision, was used to separate 22 bulls into two groups (mg-A and mg-B) based on their increasing motility. Sperm quality parameters were also examined including velocity, mitochondrial membrane potential (MMP) by the JC-1 method, head defects using William staining, and DNA fragmentation by Halomax. TNPs genes abundance was performed using the RT-qPCR method, and the protein abundance was examined with the EIA approach. The fertility rate was also analyzed based on the conception rate generated from each bull in the field, with the data obtained from iSIKHNAS. The results showed that TNPs genes and protein abundance were significantly higher (P < 0.05) in mg-A compared to mg-B, followed by various sperm quality parameters and fertility rates (P < 0.05). Positive correlations were found in TNPs genes and protein abundance with motility, velocity, MMP, and fertility (P < 0.01). Meanwhile, a negative correlation (P < 0.01) was found between head defects and DNA fragmentation. These results showed the potential of TNPs as sperm motility markers and bull fertility.

Effect of the oxygenic groups on activated carbon on its hemocompatibility

In this research, the effect of the oxygenic groups on activated carbon on its hemocompatibility was studied by liquid-phase oxidation to introduce oxygenic groups on its surface and subsequent heat treatment under a nitrogen environment to remove these groups. Hemocompatibility was assessed through coagulation, hemolysis, platelet adhesion, and protein adsorption using rabbit blood samples. Results showed that an increasing presence of oxygenic groups improved hemocompatibility, evidenced by enhanced coagulation, reduced hemolysis, better platelet adhesion, and decreased fetal bovine serum protein adsorption. Conversely, the removal of oxygenic groups diminished hemocompatibility, except for coagulation when groups were removed at 250 ℃ for 15 min. Therefore, this research presents a promising route to enhance the hemocompatibility of activated carbon, offering insights into surface modification for improved biomaterial design.

Contrasting effects of molecular crowding on the membrane-perturbing and chaperone-like activities of major bovine seminal plasma protein, PDC-109

Crowded environments inside cells and biological fluids greatly affect protein stability and activity. PDC-109, a polydisperse oligomeric protein of the bovine seminal plasma selectively binds choline phospholipids on the sperm cell surface and causes membrane destabilization and lipid efflux, leading to acrosome reaction. PDC-109 also exhibits chaperone-like activity (CLA) and protects client proteins against various kinds of stress, such as high temperature and low pH. In the present work, we have investigated the effect of molecular crowding on these two different activities of PDC-109 employing Dextran 70 (D70) – a widely used polymeric dextran – as the crowding agent. The results obtained show that presence of D70 markedly increases membrane destabilization by PDC-109. Isothermal titration calorimetric studies revealed that under crowded condition the binding affinity of PDC-109 for choline phospholipids increases approximately 3-fold, which could in turn facilitate membrane destabilization. In contrast, under identical conditions, its CLA was reduced significantly. The decreased CLA could be correlated to reduced surface hydrophobicity, which was due to stabilization of the protein oligomers. These results establish that molecular crowding exhibits contrasting effects on two different functional activities of PDC-109 and highlight the importance of microenvironment of proteins in modulating their functional activities.

Polycation-Intercalated MXene Membrane with Enhanced Permselective and Anti-Microbial Properties.

Two-dimensional (2D) nanomaterial-based membranes feature attractive properties for molecular separation and transport, which exhibit huge potential in various chemical processes. However, the low permeability and bio-fouling of the MXene membrane in water treatment become huge obstacles to its practical application. Herein, a highly permselective and anti-bacterial 2D nanofiltration membrane is fabricated by intercalating a polycation of polydiallyldimethylammonium chloride (PDDA) into the Ti3C2Tx MXene laminar architecture through a facile and patternable electrostatic assembly strategy. As a result, the as-fabricated Ti3C2Tx/PDDA composite membrane exhibits higher water permeance up to 73.4 L m-2 h-1 with a rejection above 94.6% for MgCl2. The resultant membrane simultaneously possesses good resistance to swelling and long-term stability in water environments, even after 8 h. Additionally, the Ti3C2Tx/PDDA membrane also demonstrates a high flux recovery ratio of nearly 96.1% to bovine serum albumin proteins after being cleaned. More importantly, the current membrane shows excellent anti-adhesive and anti-microbial activity against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus), with inhibition rates of 90% and 95% against E. coli and S. aureus, respectively. This holds great potential for the application of the polyelectrolyte-intercalated MXene membrane in serving as a promising platform to separate molecules and/or ions in an aquatic environment.

Bovine herpesvirus-1 gE protein inhibits IFN-β production to enhance replication by promoting MAVS ubiquitination and interfering with the interaction between IRF3 and CBP/p300

Bovine herpesvirus-1 (BoHV-1) can infect all breeds of cattle and cause respiratory and genital tract diseases. In the process of viral infection, viruses can use their own proteins to suppress the innate immunity of the host and promote its replication; however, the mechanism by which BoHV-1 evades the innate immune response is not fully understood. In this study, we found that rabbits inoculated with the live gene deletion vaccine BoHV-1-△gI/gE/TK generated higher interferon-β (IFN-β) production in the serum, liver, lung and kidney than rabbits inoculated with wt BoHV-1, which led to milder lesions in the lung and kidney. We performed gene deletion and ectopic expression experiments on viral proteins and found that gE was the major protein that inhibited IFN-β expression. Further studies showed that MAVS and IRF3 were the targets of gE, and the specific mechanism was that gE inhibited IFN-β production by promoting MAVS ubiquitination and interfering with the interaction between IRF3 and CBP/p300. These results suggest a new way of BoHV-1 inhibition of IFN-β production to evade the host innate immunity.

Evaluation of in vitro antirotaviral activity of lactoferrin from different species using a human intestinal model

Rotaviruses are the leading agents of severe diarrheal disease in infants and young children and complementary strategies to vaccination are needed. Therefore, we evaluated the activity of lactoferrin (LF) from different species against rotavirus in differentiated Caco-2/TC7 cells. The mechanism of rotavirus inhibition and the influence of iron saturation and sialic acid content were also investigated. Furthermore, the effect of bovine LF on Toll-like receptor expression (TLRs) during rotavirus infection was studied. LF presented high inhibitory activity against rotavirus above 8 mg mL−1, the bovine protein being the most potent. The antirotaviral mechanism of LF was mainly related to the virus neutralisation at an early step of infection. Interestingly, a direct relationship between rotavirus neutralisation activity and content of sialic acid in LFs was observed. Finally, the neutralisation of rotavirus by LF leaded to a decreased expression of TLRs in Caco-2/TC7 cells, with a more evident effect on TLR7.

Experimental procedures to investigate fibrillation of proteins

The unwanted phenomenon of protein fibrillation is observed in vivo and during therapeutic protein development in the industry. Protein aggregation is associated with various degenerative disorders and might induce immune-related challenges post-administration of biopharmaceutics. A pipeline for early detection, identification, and removal of pre-formed fibrils is needed to improve the quality, efficacy, and effectiveness of the formulation. Protein fibril formation is accompanied by unfolding, secondary structural changes and the formation of larger aggregates. However, most detection processes come with extensive sample preparation steps and inefficient repeatability, incurring a financial burden on research. The current article summarizes and critically discusses six simple yet powerful methods to detect aggregation phenomena in the line of detecting fibrillar aggregates in heat-induced bovine serum albumin protein. Comparing the native and heat-induced protein samples would provide insights about aggregates. Easy, inexpensive and optimized protocols for detecting the fibrillation of proteins are explained. The procedures mentioned here detected the appearance of β-sheet-rich fibrils in the heat-induced protein sample. The aggregation is characterized by enhanced thioflavin-T fluorescence, alteration in the intrinsic fluorescence, decrease in helicity and subsequent increase in β-sheet and appearance of particles with larger hydrodynamic diameters.•This article summarizes various analytical techniques to easily characterize the fibrillation of proteins.•Various techniques to detect the formation of β-sheet rich structures, changes in the secondary structures and size of aggregates have been discussed.•The stated methodologies are validated on a model protein, albumin.

Antiapoptotic and chemotaxis-stimulating effects of poly (d, l-lactide-co-glycolide)-chitosan and whey proteins against aflatoxicosis-induced splenic and thymic atrophy

BackgroundAflatoxin B (AFB) induces toxicological effects on the liver and immune organs. The whey proteins can modulate the immune response during aflatoxicosis. Our work evaluates the novel polylactic acid-glycolic acid-chitosan-encapsulated bovine and camel whey proteins against AFB-induced thymic and splenic atrophy in rats.Methods and resultsSeventy adult male Wister albino rats were divided into a control healthy group (G1) and six AFB1-intoxicated groups (G2–G7). One of the following supplements: distilled water, camel whey proteins (CWP), bovine whey proteins, poly (d, l-lactide-co-glycolide) (PLGA)- chitosan-loaded with camel whey protein microparticles (CMP), PLGA-chitosan loaded with bovine whey protein microparticles (BMP), and PLGA-chitosan nanoparticles were administered as prophylactic supplements to AFB1-intoxicated groups. The AFB-treated group showed significantly higher hepatic levels of oxidative stress and lower levels of antioxidants. In the aflatoxicated group, atrophy of the splenic lymphatic nodules and disfigurement in the organisation with an apparent decrease in the thickness of the cortex in the thymus were observed, as well as a decrease in splenic and thymic CD4+T and CD8+T lymphocytes. Moreover, CXCL12 levels were downregulated, whereas tumour necrosis factor-alpha, nuclear factor kappa B, and cleaved caspase-3 levels were upregulated. CWP, BMP, and CMP supplements markedly decreased oxidative stress, inflammation, and apoptosis, as well as significantly raised CXCL12, CD4+T, and CD8+T cells.ConclusionsThe CWP, BMP, and CMP supplements rescue the liver and immune tissues from the toxic effects of AFB through their antioxidant, antiapoptotic, anti-inflammatory, and chemotaxis-enhancing roles.

Preparation of chitosan/citral forward osmosis membrane via Schiff base reaction with enhanced anti-bacterial properties

In this study, hydrogels generated by the Schiff base reaction between citral and chitosan (CS) were used for the first time to improve the anti-bacterial property of forward osmosis (FO) membranes. The composite membranes were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), Water contact angle (WCA), Zeta potential and confocal laser scanning microscopic (CLSM). In the FO filtration experiment, the membrane performance of TFC-1 with 1 M sodium chloride solution as the draw solution and deionized water as the feed solution was the best, with the water flux of 25.54 ± 0.7 L m−2 h−1 and the reverse salt flux of 4.7 ± 0.4 g m−2 h−1. Although the hydrogel coating produced a certain hydraulic resistance, the flux of the modified membrane was only reduced by about 8%, compared with the unmodified membrane. However, the anti-bacterial property (Pseudomonas aeruginosa) and anti-fouling properties (bovine serum protein and lysozyme protein) of the modified membranes were improved, showing good antibacterial properties (99%) and flux recovery rate (over 90%). The modified method has the advantages of easy access to raw materials, simple operation and no risk of secondary pollution, which can effectively reduce the cost of chemical cleaning and extend the service life of the membrane. The modification of membrane by chitosan-based hydrogel is a promising option in the field of membrane anti-bacteria.

Summary-data based Mendelian randomization identifies gene expression regulatory polymorphisms associated with bovine paratuberculosis by modulation of the nuclear factor Kappa β (NF-κß)-mediated inflammatory response

Genome-wide association studies (GWAS) have identified host genetic variants associated with paratuberculosis (PTB) susceptibility. Most of the GWAS-identified SNPs are in non-coding regions. Connecting these non-coding variants and downstream affected genes is a challenge and, up to date, only a few functional mutations or expression quantitative loci (cis-eQTLs) associated with PTB susceptibility have been identified. In the current study, the associations between imputed whole-genome sequence genotypes and whole RNA-Sequencing data from peripheral blood (PB) and ileocecal valve (ICV) samples of Spanish Holstein cows (N = 16) were analyzed with TensorQTL. This approach allowed the identification of 88 and 37 cis-eQTLs regulating the expression levels of 90 and 37 genes in PB and ICV samples, respectively (False discorey rate, FDR ≤ 0.05). Next, we applied summary-based data Mendelian randomization (SMR) to integrate the cis-eQTL dataset with GWAS data obtained from a cohort of 813 culled cattle that were classified according to the presence or absence of PTB-associated histopathological lesions in gut tissues. After multiple testing corrections (FDR ≤ 0.05), we identified two novel cis-eQTLs affecting the expression of the early growth response factor 4 (EGR4) and the bovine neuroblastoma breakpoint family member 6-like protein isoform 2 (MGC134040) that showed pleiotropic associations with the presence of multifocal and diffuse lesions in gut tissues; P = 0.002 and P = 0.017, respectively. While EGR4 acts as a brake on T-cell proliferation and cytokine production through interaction with the nuclear factor Kappa β (NF-κß), MGC134040 is a target gene of NF-κß. Our findings provide a better understanding of the genetic factors influencing PTB outcomes, confirm that the multifocal lesions are localized/confined lesions that have different underlying host genetics than the diffuse lesions, and highlight regulatory SNPs and regulated-gene targets to design future functional studies.

Development and Comparative Evaluation of Two Highly Sensitive Immunosensor Platforms for Trace Determination of Copper Ions in Drinking Water Using a Monoclonal Antibody Specific to Copper-EDTA Complex.

This study describes the development of two highly sensitive immunosensor platforms for the trace determination of copper ions, Cu(II), in drinking water. These platforms were a microwell-based enzyme-linked immunosorbent assay (ELISA) and a kinetic exclusion assay (KinExA) with a KinExATM 3200 immunosensor. Both ELISA and KinExA were developed utilizing the same antibody and coating reagent. The antibody was a mouse monoclonal antibody, designated as 8D66, that specifically recognized Cu(II)-ethylenediamine tetraacetic acid complex (Cu(II)-EDTA) but did not recognize Cu(II)-free EDTA. The 8D66 monoclonal antibody was generated by the fusion of spleen cells of an immunized BALB/c mouse with SP2/0-Ag14 myeloma cells. The immunogen was a protein conjugate of Cu(II)-EDTA with keyhole limpet hemocyanin protein. The coating reagent was Cu(II)-EDTA covalently linked to bovine serum albumin protein (Cu(II)-EDTA-BSA). Both assays involved the competitive binding reaction between Cu(II)-EDTA complexes, formed in the sample solution, and Cu(II)-EDTA-BSA conjugate which has been immobilized onto ELISA plates (in ELISA) or polymethylmethacrylate beads (in KinExA) for a limited quantity of binding sites of the 8D66 antibody. In ELISA, color signals were generated by a peroxidase-labeled secondary antibody and 3,3',5,5'-tetramethylbenzidine substrate. In KinExA, a fluorescein isothiocyanate-labeled secondary antibody was used to generate KinExAgram (trend-line fluorescence responses vs. time). The conditions of both ELISA and KinExA were investigated, and the optimum procedures were established. Both ELISA and KinExA were validated, and all validation parameters were acceptable. Many different metal ions that are commonly encountered in drinking water did not interfere with the Cu(II) analysis by both ELISA and KinExA. Both assays were applied to the determination of Cu(II) in drinking water with satisfactory accuracy and precision. Both assays were compared favorably with inductively coupled plasma atomic emission spectroscopy in terms of their abilities to accurately and precisely determine Cu(II) in drinking water samples. A comparative evaluation of ELISA and KinExA revealed that KinExA had a higher sensitivity and better precision than ELISA, whereas both assays had comparable accuracy. Both ELISA and KinExA were superior to the existing atomic spectrometric methods for Cu(II) in terms of sensitivity, convenience, and analysis throughputs. The proposed ELISA and KinExA are anticipated to effectively contribute to assessing Cu(II) concentrations and control the exposure of humans to its potential toxicities.

A novel dopamine electrochemical sensor based on multiwall carbon nanotubes-cetyltrimethylammonium bromide/nitrogen doped ultra-thin carbon nanosheets composites modified glassy carbon electrode

Dopamine (DA), as an important neurotransmitter, plays pivotal roles in addiction and some diseases. Fast and sensitive detection is of great value. Herein, a novel DA sensor based on multiwall carbon nanotubes-cetyltrimethylammonium bromide/zinc/cobalt @ nitrogen doped ultra-thin carbon nanosheets (MWCNTs-CTAB/Zn/Co@N-CNSs) was constructed. The 2D Zn/Co@N-CNSs was derived from the Zn/Co-ZIF precursor which was obtained by the simple salt stencil method. For the detection of DA, the MWCNTs-CTAB/Zn/Co@N-CNSs/GCE presented wide linear range (0.10 μM–12.0 μM) and low detection limit (LOD, 0.037 μM, (S/N = 3)).With the help of density function theory calculation results, the redox mechanism and electrochemical reaction sites of DA were further revealed. Besides, MWCNTs-CTAB/Zn/Co@N-CNSs/GCE achieved good recovery and accuracy in detecting DA in actual samples (bovine serum protein and human serum).

Kinetic-conceptual model of the hydrolysis of bovine plasma proteins - ALCALASE® 2.9L: The role of inhibition by product

In the present work, the inhibitory effect of the peptide fractions, obtained through enzymatic hydrolysis of bovine plasma was evaluated, on the enzyme used in the reaction (Alcalase 2.4 L). In this sense, Ultra-filtered peptide fractions of different molecular sizes (A: Fraction>10; B: Fraction 10-3 kDa; and C: Fraction <3 kDa), were used to verify the impact on the total hydrolysis rate. The Fractions between 3 and 10 kDa were refined to fit a conceptual kinetic model which considers inhibition by product and substrate. Additionally, the inactivation of the enzyme through the reaction time was evaluated and its effects incorporated into the model. It was shown that some peptides released in the successive stages of the reaction can in turn inhibit the activity of the hydrolyzing enzyme. The model evaluated suggests a time-varying expression of inhibition parameters as a function of the initial substrate concentration in the reaction. This is based on the kinetic changes of the product profiles for each reaction time in the evaluated operating conditions (S0 variable). A greater inhibitory effect due to the products is evidenced when the reaction occurs with a higher load of the initial substrate (S0 = 20 g/L).

Bovine bone protein-quercetin conjugates for improved physical and oxidative stability of oil-in-water emulsions

To enhance the functional properties of bovine bone proteins (BBP) for food-related applications, their quercetin conjugates (BBP-QC), with antioxidant and emulsifying properties, were prepared by alkaline induction. The structural changes of BBP-QC conjugates were investigated, and their different concentrations were examined for the physical and oxidative stability of oil-in-water (O/W) emulsions. Structural characterization using Fourier transform infrared spectroscopy (FT-IR) and fluorescence spectroscopy confirmed the covalent binding of QC with BBP resulting in a conformational change in BBP. Particle size and ζ-potential measurements showed that 0.6% BBP-QC effectively improved the physical stability, increased the net charge of the O/W emulsion. Fluorescence microscopy observation of emulsion microstructure showed that the distribution of oil droplets in the BBP-QC stabilized emulsion was smaller and more uniform than that without the conjugates and effectively alleviated the phase separation in the emulsion. The 0.6% BBP-QC emulsion had a peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) value of only 1.45 mmol/kg and 3.32 μmol/kg after 12 days. Additionally, BBP-QC stabilized emulsions exhibited excellent antioxidant capacity in vitro antioxidant experiments. This study highlights the excellent properties of BBP-QC conjugates as novel emulsifiers with high antioxidant activity and potential applications in the food industry.

Structural analysis of open reading frames of bovine immunodeficiency virus proteins

The goal of this study was determining the structural organization peculiarities of the ORF2 and ORF3 proteins of the bovine immunodeficiency virus (BIV). Five ORFs were determined for two BIV isolates with complete genome using the ATGpr software, which permits effective prediction of translation initiation codons with nucleotide accuracy. Phyre2 software was used to predict, analyze the secondary structure and function of proteins. PONDR-FIT software was used to search for protein fragments in a disordered or natively unfolded state. Analysis of the amino acid composition of ORF2 and ORF3 proteins of BIVisolates regarding the presence of nonpolar, polar, aromatic, and hydrophobic amino acid residues was carried out using PSIPRED software. Models of the 3D-structure of proteins were obtained by I-TASSER server. 14% of α helices, 17% of β strands and 43% of disordered structure are predicted for the ORF3 protein. 37% of α helices, 0% of β strands, and 41% of disordered structure were determined for Gag polyprotein, which is translated from ORF2. The distribution of charged amino acid residues characterizes the surface properties of proteins. Their number reaches 23.9% for ORF2 protein. The amount of Arg is 5.2%, Lys — 8.0%, Glu — 7.3%, Asp — 3.4%. The total number of charged amino acid residues of ORF3 is 23.3%. The number of Arg is 12.6%, Lys — 4.9%, Glu — 1.9%, Asp — 3.9%. Only two ORFs of five ones coincide in nucleotide length (and, therefore, in length of corresponding proteins) for the two BIV isolates. The ORF3 protein belongs to the intrinsically disordered proteins that cannot be stably folded into a unique three-dimensional structure under physiological conditions, and the Gag polyprotein, which is translated from ORF2, belongs to the class of fully structured proteins. The secondary structure of both proteins shows the presence of α-helices

Characterization of bovine immunodeficiency virus genes and proteins

The goal of the study was determining the effect of natural selection on the bovine immunodeficiency virus (BIV) through the identification of polymorphisms by comparing a number of genes, open reading frames and proteins and analyzing the effect of nonsynonymous substitutions in the Vif protein of BIV isolates on the Vif conformational parameters. The selection pressure on the genes was estimated by Tajima test, as well as the determination of the ratio of nonsynonymous substitutions (Ka) to synonymous (Ks) Ka/Ks. Ka and Ks coefficients, their ratio (Ka/Ks) were calculated on the basis of alignments of amino acid and nucleotide sequences of the vif gene of BIV isolates. The nonsynonymous (dN) to synonymous (dS) substitution rate ratio per nucleotide site dN/dS was calculated to estimate the effect of selection on the vif gene by SLAC method on Datamonkey server. The number of hydrogen bonds, α-helices, β-sheets, β-turns for the protein tertiary structures of proteins was determined by I-TASSER server. Genes, open reading frames (ORFs) and the U3 regulatory region of BIV genome which are under the influence of selection have been identified. Gag, pol, s, vif genes, ORF W and ORF Y are under the negative (purifying) selection pressure. Env gene and the U3 regulatory region are under positive selection. Shannon entropy analysis (peaks that are specific to the positions of amino acid residues), interpreted as polymorphisms, revealed 16, 8, and 4 nonsynonymous substitutions for Pol, Gag, and Vif BIV proteins, respectively. Significant changes in the number of hydrogen bonds, α-helices, β-layers, β-turns were determined by the analysis of the effect of four nonsynonymous substitutions in the Vif protein on the conformational parameters of Vif of two BIV isolates. The multidirectional effect of selection on BIV genes is shown

Terahertz wave biomolecular sensor based on all-dielectric high Q metasurface

We propose a C-type all-dielectric metasurface. By analyzing the electromagnetic field of the metasurface unit structure, it is found that this type of metasurface unit can achieve high Q value. The unit structure parameters of high quality factor are obtained by optimizing the unit structure cycle, surface structure size and other parameters. We apply this all-dielectric metasurface to biomolecular sensing. By changing the harmonic amplitude of resonant frequency, the detection limit of bovine serum protein solution with different mass fractions was 0.05 mg/mL, which laid the foundation for the labeling detection of biomolecules.

Mammalian odorant-binding proteins are prone to form amorphous aggregates and amyloid fibrils

Odorant-binding proteins are involved in perceiving smell by capturing odorants within the protein's β-barrel. On the example of bovine odorant-binding protein (bOBP), the structural organization of such proteins and their ability to bind ligands under various conditions in vitro were examined. We found a tendency of bOBP to form oligomers and small amorphous aggregates without disturbing the integrity of protein monomers at physiological conditions. Changes in environmental parameters (increased temperature and pH) favored the formation of larger and dense supramolecular complexes that significantly reduce the binding of ligands by bOBP. The ability of bOBP to form fibrillar aggregates with the properties of amyloids, including high cytotoxicity, was revealed at sample stirring (even at physiological temperature and pH), at medium acidification or pre-solubilization with hexafluoroisopropanol. Fibrillogenesis of bOBP was initiated by the dissociation of the protein's supramolecular complexes into monomers and the destabilization of the protein's β-barrels without a significant destruction of its native β-strands.

Response of Osteoblasts on Amine-Based Nanocoatings Correlates with the Amino Group Density.

Increased life expectancy in industrialized countries is causing an increased incidence of osteoporosis and the need for bioactive bone implants. The integration of implants can be improved physically, but mainly by chemical modifications of the material surface. It was recognized that amino-group-containing coatings improved cell attachment and intracellular signaling. The aim of this study was to determine the role of the amino group density in this positive cell behavior by developing controlled amino-rich nanolayers. This work used covalent grafting of polymer-based nanocoatings with different amino group densities. Titanium coated with the positively-charged trimethoxysilylpropyl modified poly(ethyleneimine) (Ti-TMS-PEI), which mostly improved cell area after 30 min, possessed the highest amino group density with an N/C of 32%. Interestingly, changes in adhesion-related genes on Ti-TMS-PEI could be seen after 4 h. The mRNA microarray data showed a premature transition of the MG-63 cells into the beginning differentiation phase after 24 h indicating Ti-TMS-PEI as a supportive factor for osseointegration. This amino-rich nanolayer also induced higher bovine serum albumin protein adsorption and caused the cells to migrate slower on the surface after a more extended period of cell settlement as an indication of a better surface anchorage. In conclusion, the cell spreading on amine-based nanocoatings correlated well with the amino group density (N/C).