Ovomucin Research Articles

Preparation and characterization of ovomucin self-assembly nanoparticles under glycerol compression for astaxanthin delivery: Sustained release and antioxidant activity.

Astaxanthin (AST) is a natural hydrophobic nutrient with various biological activities, but its low solubility limits its application. In this study, self-assembly nanoparticles were prepared by ovomucin (OVM) and Ca2+ with the enhancement of glycerol to deliver AST. Glycerol compressed the particle size of nanoparticles from 175.7±1.8 to 142.9±0.6nm, and the nanoparticles had a strong negative charge (-28.9±0.6mV). Ultraviolet-visible spectroscopy and X-ray diffraction (XRD) confirmed the successful encapsulation of AST in an amorphous form with a high encapsulation efficiency (82.9%±2.1%). Fourier transform infrared and circular dichroism analyses demonstrated that nanoparticles formation mainly involved electrostatic interactions and hydrophobic interactions. AST in nanoparticles presented excellent gastric juice resistance and sustained release ability, whereas free radical scavenging efficiency reached up to 75%. In addition, the nanoparticles had no apparent toxicity to cell viability. This study is expected to provide a new insight into the safe and efficient delivery of AST, while demonstrating the potential of OVM as a delivery carrier in the food and health industries.

Crucial effect of ovomucin on alkali-induced egg white gel formation: Properties, structure and facilitation mechanism

Alkali-induced preserved egg gel formation is a dynamic process that involves complex protein changes. Ovomucin (OVM) is closely associated with the gel properties of egg white. In this study, the effect of OVM in alkali-induced egg white gel (AEWG) formation was investigated. The results suggested that OVM reduced the gel formation time by 15 %. The mechanical properties of the fully formed gel were also improved by OVM. Specifically, OVM increased the storage modulus (G′) of the gel by 1.5-fold, while the hardness significantly increased from 78.90 ± 4.24 g to 99.80 ± 9.23 g. Low-field nuclear magnetic resonance (LF-NMR) demonstrated that OVM significantly shortened T23 relaxation time and reduced the water mobility, thus increasing the water holding capacity (WHC). Meanwhile, the presence of OVM resulted in a more homogeneous and denser microscopic morphology of the gel. Selective solubility experiments revealed that disulfide bonds are the primary force in gel formation. OVM promoted the formation of more disulfide bonds, which increased the strength and stability of the gel network. Overall, this research proved OVM plays a critical role in the performance improvement of AEWG, which provides a new insight into the quality control of preserved egg and protein gel foods.

Anti-biofilm effect of enzymatic hydrolysates of ovomucin in Listeria monocytogenes and Staphylococcus aureus

Despite modern advances in food hygiene, food poisoning due to microbial contamination remains a global problem, and poses a great threat to human health. Especially, Listeria monocytogenes and Staphylococcus aureus are gram-positive bacteria found on food-contact surfaces with biofilms. These foodborne pathogens cause a considerable number of food poisoning and infections annually. Ovomucin (OM) is a water-insoluble gel-type glycoprotein in egg whites. Enzymatic hydrolysis can be used to improve the bioactive properties of OM. This study aimed to investigate whether ovomucin hydrolysates (OMHs) produced using five commercial enzymes (Alcalase®, Bromelain, α-Chymotrypsin, Papain, and Pancreatin) can inhibit the biofilm formation of L. monocytogenes ATCC 15313, L. monocytogenes H7962, S. aureus KCCM 11593, and S. aureus 7. Particularly, OMH prepared with papain (OMPP; 500 μg/mL) significantly inhibited biofilm formation in L. monocytogenes ATCC 15313, L. monocytogenes H7962, S. aureus KCCM 11593, and S. aureus 7 by 85.56 %, 80.28 %, 91.70 %, and 79.00 %, respectively. In addition, OMPP reduced the metabolic activity, exopolysaccharide production (EPS), adhesion ability, and gene expression associated with the biofilm formation of these bacterial strains. These results suggest that OMH, especially OMPP, exerts anti-biofilm effects against L. monocytogenes and S. aureus. Therefore, OMPP can be used as a natural anti-biofilm agent to control food poisoning in the food industry.

Natural Biomolecule Ovomucin-Chitosan Oligosaccharide Self-Assembly Nanogel for Lutein Application Enhancement: Characterization, Environmental Stability and Bioavailability.

As an essential nutrient, lutein (LUT) has the ability to aid in the prevention of eye diseases, cardiovascular diseases, and cancer. However, the application of LUT is largely restricted by its poor solubility and susceptibility to oxidative degradation. Thus, in this study, LUT-loaded nanogel (OVM-COS-LUT) was prepared by a self-assembly of ovomucin (OVM) and chitosan oligosaccharide (COS) to enhance the effective protection and bioavailability of LUT. The nanogel had excellent dispersion (PDI = 0.25) and an 89.96% LUT encapsulation rate. XRD crystal structure analysis confirmed that the encapsulated LUT maintained an amorphous morphology. In addition, the nanogel showed satisfactory stability with pH levels ranging from 2 to 9 and high ionic strengths (>100 mM). Even under long-term storage, the nanogel maintained an optimistic stabilization and protection capacity; its effective retention rates could reach 96.54%. In vitro, digestion simulation showed that the bioaccessibility and sustained release of OVM-COS-LUT nanogel was superior to that of free LUT. The nanogel provided significant antioxidant activity, and no significant harmful effects were detected in cytotoxicity analyses at higher concentrations. In summary, OVM-COS-LUT can be utilized as a potential safe oral and functional carrier for encapsulating LUT.

Immunostimulatory Effect of Ovomucin Hydrolysates by Pancreatin in RAW 264.7 Macrophages via Mitogen-Activated Protein Kinase (MAPK) Signaling Pathway.

Ovomucin (OM), which has insoluble fractions is a viscous glycoprotein, found in egg albumin. Enzymatic hydrolysates of OM have water solubility and bioactive properties. This study investigated that the immunostimulatory effects of OM hydrolysates (OMHs) obtained by using various proteolytic enzymes (Alcalase®, bromelain, α-chymotrypsin, Neutrase®, pancreatin, papain, Protamax®, and trypsin) in RAW 264.7 cells. The results showed that OMH prepared with pancreatin (OMPA) produced the highest levels of nitrite oxide in RAW 264.7 cells, through upregulation of inducible nitric oxide synthase mRNA expression. The production of pro-inflammatory cytokines such as tumor necrosis factor-α and interleukin-6 were increased with the cytokines mRNA expression. The effect of OMPA on mitogen-activated protein kinase signaling pathway was increased the phosphorylation of p38, c-Jun NH2-terminal kinase, and extracellular signal-regulated kinase in a concentration-dependent manner. Therefore, OMPA could be used as a potential immune-stimulating agent in the functional food industry.

Ovomucin and its hydrolysates differentially influenced colitis severity in Citrobacter rodentium-infected mice.

Egg white protein ovomucin and its hydrolysates were previously reported to exhibit anti-inflammatory and anti-adhesive activities. However, their potential to regulate pathogen colonization and disease severity has not been fully characterized. To investigate the effects of ovomucin (OVM) and its hydrolysates including ovomucin-Protex 26L (OP) and -pepsin/pancreatin (OPP) on host resistance to pathogen infection, a well-documented colitis model in mice for attaching and effacing E. coli pathogens, Citrobacter rodentium, was used in the current study. C57Bl/6J female mice were fed on a basal diet supplemented with OVM or its hydrolysates for 3 weeks prior to the C. rodentium challenge, with the dietary treatments continued for seven days. Body weight was not affected throughout the experimental period. OP supplementation resulted in lower (P < 0.05) pathogen loads at 7 dpi. Attenuated colitis severity was observed in mice that received OVM and OP, as indicated by reduced colonic pathological scores and pro-inflammatory responses compared with the infected control group. In contrast, OPP consumption resulted in enhanced C. rodentium colonization and disease severity. Notably, reduced microbial diversity indices of the gut microbiota were observed in the OPP-supplemented mice compared with the OVM- and OP-supplemented groups. This study showed the potential of OVM and OP to alleviate the severity of colitis induced by infection while also suggesting the opposite outcome of OPP in mitigating enteric infection.

Exploring the binding effect and mechanism of glycyrrhizin to ovomucin by combining spectroscopic analysis and molecular docking

Ovomucin (OVM) is an ideal natural macromolecular glycoprotein extracted from eggs with good adhesion. Based on the defect that glycyrrhizin (GL) has good antiviral activity but fast metabolism, this study aimed to explore the binding effect and mechanism of GL to OVM, using multi-spectroscopic techniques, isothermal titration calorimetry (ITC), and molecular docking. The adhesion ability of OVM to the hydrophilic interface and GL was first demonstrated by dual polarization interferometry (DPI) analysis and binding capacity assay, and the OVM-GL complex exhibited a similar affinity for the spike protein of COVID-19. The spectroscopic results show that GL can quench the inherent fluorescence and change the glycosidic bond and secondary structure of OVM. The ITC measurements suggested that the binding was exothermic, the hydrogen bond was the dominant binding force for forming OVM-GL. Finally, molecular docking results indicated that GL has hydrogen bond interaction with several amino acid residues located in α-OVM and β-OVM while embedding into the hydrophobic pocket of OVM via hydrophobic interactions. In conclusion, OVM can adhere to the hydrophilic interface and bind to GL through hydrogen bonding and hydrophobic interactions to form a stable complex, that is expected to be helpful in virus prophylaxis.

Mechanism of heat‐induced thinning of thick egg white in weak alkaline condition: molecular aggregation, functional and structure properties analysis

SummaryThe thinning of thick egg white (KEW) was simulated by weak alkaline (pH 10.0) combined with mild heat (50 °C) treatment. The molecular aggregation, functional and structural characteristics changes in simulated KEW thinning process were comprehensively studied. It was found that KEW molecule entered “molten pellet (MG)” state with decline of apparent viscosity of KEW. At this time, particle size increased by 40.9%, surface hydrophobicity and solubility declined 11.3% and 8.9%, respectively. However, with more mild heating time, KEW structure gradually unfolded, ovomucin (OVM) degraded, particle size diminished significantly. Surface hydrophobicity and solubility increased 6.6% and 19.7%, respectively. Functional properties indicated that thermal gel of KEW gradually became soft and tough, water holding capacity (WHC) advanced by 10%, emulsifying property significantly improved by 40%. Moreover, correlation analysis indicated that tertiary structure was correlated with particle size (P &lt; 0.01), secondary structure related to hardness and WHC (P &lt; 0.05). Through the results of SDS‐PAGE and comparison with KEW simple mild heating, it was concluded that rise of pH was intrinsic driving force of KEW thinning. Therefore, this study provided a new insight for revealing the thinning mechanism of KEW and a scientific basis for its industrial application.

Glycerol-compressed self-assembly nanogel based on ovomucin and chito-oligosaccharide: A novel green strategy for curcumin delivery

Nano-gel technology has been one of the popular methods to solve the low bioavailability of hydrophobic active substances. In this work, Ovomucin (OVM) was combined with chito-oligosaccharide (COS) by self-assembly, followed by condensation of complexes initiated via glycerol solution to produce green nanogel delivering curcumin. The successful encapsulation of curcumin was confirmed by UV–Vis spectrum and fluorescence microscopy. In addition, the morphology of the nanogel was nearly spherical with a small average hydrodynamic diameter (115.43nm), uniform particle size distribution (PDI = 0.266), and intense surface negative charge (−23.56mV). The vitro-release simulation assay showed that the nano-gels have good sustained release ability. The antioxidant activities of free curcumin and curcumin-loaded nano-gels were investigated by ABTS, DPPH, and H 2 O 2. The results of FTIR and XRD confirmed that curcumin disperses uniformly in the whole system through hydrogen bond and hydrophobic interaction between the nanogel. Curcumin in nanogel enabled easier access to free radicals in water phase, thereby possessing stronger antioxidant activity than free curcumin. Furthermore, cytotoxicity test results showed that nanogel has no obvious toxicity signs on cell viability. Hence, this work holds a grand promise for safe and efficient oral curcumin delivery while possessing universal significance for the extension of using OVM as an efficient and functional encapsulating agent to broad applications in food and health industries. OVM was mixed with curcumin and bound to each other by hydrophobic interaction and hydrogen bond. COS induced the formation of early nanogel by electrostatic action. Glycerol compressed the gel to produce the final nanogel. • The nanogel was synthesized in a green way by glycerol compression and self-assembly. • The average hydrodynamic diameter of curcumin-loaded OVM nanogel was only 115.43 ± 1.60 nm and size distribution was narrow. • The fluorescence quenching of the nanogel confirmed the encapsulation of curcumin. • The Cur-OVM-COS nanogel showed a better sustained-release effect during simulated gastrointestinal digestion than the free curcumin. • The antioxidant activity of encapsulated curcumin was improved.

Ultrasound improves the thermal stability and binding capacity of ovomucin by promoting the dissociation of insoluble ovomucin aggregates

Ovomucin (OVM) is a natural glycoprotein with various biological activities but poor solubility. This study aimed to enhance the solubility of OVM by using an ultrasonic-assisted method. The effect of ultrasound (US) on the structure, thermal stability and biological functions of OVM aggregates was evaluated. It was found that insoluble OVM aggregates were dissociated and the solubility increased significantly to 90.0 % after US under 400 W for 45 min. US also improved the onset temperature (To) and denaturation temperature (Td) of OVM. More importantly, the cholesterol binding capacity of both OVM and its digestion products were significantly improved after US (p < 0.05). The gastrointestinal digestion products of US-OVM also showed higher α-amylase and α-glucosidase inhibition than native OVM aggregates. US-induced dissociation of OVM aggregates and the conversion of β-sheet and β-turn to random coil, resulting in the exposure of hydrophobic binding sites may be an important reason for the enhanced stability and adsorption capacity. These findings suggested that US was an effective method for preparing soluble OVM and improved its adsorption capacity, which can further facilitate the application of OVM in the food industry.

Effects of ultrasonic treatment on ovomucin: Structure, functional properties and bioactivity

The effects of ultrasonic treatment on the structure, functional properties and bioactivity of Ovomucin (OVM) were investigated in this study. Ultrasonic treatment could significantly enhance OVM solubility without destroying protein molecules. The secondary structure changes, including β-sheet reduction and random coil increase, indicate more disorder in OVM structure. After ultrasonic treatment, the OVM molecule was unfolded partially, resulting in the exposure of hydrophobic regions. The changes in OVM molecules led to an increase in intrinsic fluorescence and surface hydrophobicity. By detecting the particle size of protein solution, it was confirmed that ultrasonic treatment disassembled the OVM aggregations causing a smaller particle size. Field emission scanning electron microscopy (FE-SEM) images showed that ultrasonic cavitation significantly reduced the tendency of OVM to form stacked lamellar structure. Those changes in structure resulted in the improvement of foaming, emulsification and antioxidant capacity of OVM. Meanwhile, the detection results of ELISA showed that ultrasonic treatment did not change the biological activity of OVM. These results suggested that the relatively gentle ultrasound treatment could be utilized as a potential approach to modify OVM for property improvement.

Ovomucin Ameliorates Intestinal Barrier and Intestinal Bacteria to Attenuate DSS-Induced Colitis in Mice.

Egg white ovomucin (OVM) is homologically related to MUC2, the key component of colonic mucous layer. This study investigated the effects of orally administered OVM from egg white on the colonic mucosal barrier and the development of colitis using a colitis C57BL/6J mice model. The results showed that daily supplementation of 125 and 250 mg/kg BW of OVM partially relieved the villous destruction and loss of intestinal barrier integrity, and hence decreased the epithelial barrier permeability. The supplementation also reduced the secretion of proinflammatory cytokines TNF-α and IL-6. Besides, OVM administration significantly increased the relative abundance of intestinal beneficial bacteria including Lactobacilli, Faecalibaculum, Ruminococcus, etc. and further upregulated the production of bacterial metabolites such as short-chain fatty acids (SCFAs), which is a direct source of energy for the proliferation of epithelia and goblet cells. In conclusion, OVM from egg white ameliorates colitis by enhancing the intestinal barrier function and abundance of intestinal bacteria, thereby increasing the number of SCFAs.

Exploration of structure-activity relationship between IgG1 and IgE binding ability and spatial conformation in ovomucoid with pulsed electric field treatment

Ovomucin (OVM) is one of the most main allergens in egg white, which limits the application of egg in the field of food processing. In this study, the effect of pulsed electric fields (PEF) on the IgG1 and IgE binding capability and the composition changes of OVM was studied by indirect competitive ELISA, SDS-PAGE, Fourier transform infrared spectroscopy (FTIR), circular dichroism (CD) spectroscopy, contact angle meter, fluorescence spectrophotometer and scanning electron microscopes (SEM). The results suggested that PEF treatment couldsignificantly reduce the IgG1 and IgE binding capacity of OVM, especially under the condition of 30 kV/cm. PEF treatment could cause partial unfolding of the protein, which was attributed to the destruction of the epitope structure that binds to IgG1 and IgE in OVM. Results indicated that PEF treatment significantly changed the primary structure, secondary structure and tertiary structure of the protein. Specifically, the secondary structure of the protein was partially unwound, and hydrophobic amino acids were exposed after PEF treatment. In addition, we observed that the microstructure of the OVM also changed significantly after PEF treatment.

Sialic acid involves in the interaction between ovomucin and hemagglutinin and influences the antiviral activity of ovomucin

Ovomucin (OVM) plays an important role in inhibiting infection of various pathogens. However, this bioactivity mechanism is not much known. Here, the role of sialic acid in OVM anti-virus activity has been studied by ELISA with lectin or ligand. Structural changes of OVM after removing sialic acid were analyzed by circular dichroism and fluorescence spectroscopy. OVM could be binding to the hemagglutinin (HA) of avian influenza viruses H5N1 and H1N1, this binding was specific and required the involvement of sialic acid. When sialic acid was removed, the binding was significantly reduced 71.5% and 64.35%, respectively. Therefore, sialic acid was proved as a recognition site which avian influenza virus bound to. Meanwhile, the endogenous fluorescence and surface hydrophobicity of OVM removing sialic acid were increased and the secondary structure tended to shift to random coil. This indicated that OVM molecules were in an unfolded state and spatial conformation disorder raising weakly. Remarkably, free sialic acid strongly promoted OVM binding to HA and thereby enhanced the interaction. It may contribute to the inhibition of host cell infection, agglutinate viruses. This study can be extended to the deepening of passive immunization field.

Amino Acid Sequence of a-Subunit in Hen Egg White Ovomucin Deduced from Cloned cDNA

The primary amino acid sequence of alpha-subunit in ovomucin (OVM) from hen thick egg white was determined. The 2087 amino acid residues with a relative molecular mass of 230.9 kDa along the full length of the alpha-subunit were represented. The alpha-subunit contains domains, arranged from the N- to C-terminals in the following order: D1-D2-D'-D3-R (central region)-D4-C1-CK (Cystine-knot), in a manner similar to the arrangement of D, C and CK domains in human pre-pro-von Willebrand factor (hpp-vWF) and hMUC2. The alpha-subunit showed identities on amino acid sequences with hpp-vWF and hMUC2 at 33 and 41% in the N-terminal region and 30 and 38% in the C-terminal region, respectively. The numbers and positions of cysteine residues were highly conserved among alpha-subunit, hpp-vWF and hMUC2. However, R showed no virtual sequence homology with the corresponding regions in two proteins. It was estimated that alpha-subunit was not part of a large peptide of OVM, but was independently synthesized from beta-subunit.

Interaction between 120kDa Fragment in .BETA.-Subunit from Egg White Ovomucin and Sarcoma-180 Cells through Basic Fibroblast Growth Factor Receptor.

The mechanism of antitumor activities in hen egg white ovomucin (OVM) was analyzed by examining the interaction between the 120 kDa fragment (a highly glycosylated fragment in β-subunit from the pronase-treated OVM) and basic fibroblast growth factor receptor (bFGFR). The 120 kDa fragment, which was transblotted onto a polyvinylidene difluoride membrane after SDS-polyacrylamide gel electrophoresis, was found to interact with bFGFR. The interaction was detected by Western blotting method with mouse anti-FGFR IgM. When sarcoma-180 (SR-180) cells were cultured on addition of the 120 kDa fragment, they were observed to be in the necrotic state by transmission electron microscopy, and the 120 kDa fragment was seen to be dispersed on the cell surface by light and transmission electron microscopic observations with the immunocytochemical staining method. The growth of SR-180 cell in the presence of bFGF was reduced with increase in the amount of 120 kDa fragment added. Thus, it was found that the 120 kDa fragment interacted with SR-180 cells through bFGFR and affected them.

Light scattering study of ovomucin.

Light scattering study of ovomucin.

Reduction of ovomucin by mercaptoethanol

Reduction of ovomucin by mercaptoethanol