Omics analysis of holoproteins and modified proteins of quail egg

Investigation into Potential Allergenicity and Digestion-Resistant Linear Epitopes of Fish Skin Gelatin in Cell-Cultured Meat Scaffolds

As a key component of cell-cultured fish, fish skin gelatin (FSG)-based cell scaffold provides support structures for cell growth, proliferation, and differentiation. However, there are potential allergenicity risks contained in FSG-based scaffolds. In this study, 3D edible scaffolds were prepared by phase separation method and showed a contact angle of less than 90°, which indicated that the scaffolds were favorable for cell adhesion. Besides, the swelling ratio was greater than 200%, implying a great potential to support cell growth. The sequence homology analysis indicated that FSG was prone to cross-reaction with collagen analogues. Additionally, a food allergic model was constructed and represented that mice gavaged with cod FSG exhibited higher levels of specific antibodies, mast cell degranulation, vascular permeability, and intestinal barrier impairment than those gavaged with pangasius and tilapias FSG. Its higher allergenicity might be attributed to a higher number of digestion-resistant linear epitopes. Moreover, the higher hydrolysis degree linked to the exposure of linear epitopes to promote the combination with IgE, which was also responsible for maintaining the higher allergenicity of cod FSG. This study clarifies allergenic risks in cell-cultured fish and further study will focus on the allergenicity reduction of FSG-based cell scaffolds.

Testing adulterated liquid-egg: developing rapid detection techniques based on colorimetry, electrochemistry, and interfacial fingerprinting

To develop rapid detection techniques for liquid eggs' adulteration, three types of adulterations were considered: water dilution, manipulation of yolk ratio in whole egg, and blending different varieties of egg white or yolk. Objective: Establish detection techniques utilizing colorimetry, electrochemistry, and interfacial fingerprinting for these adulterations, respectively. Results: Colorimetry allows for detection (1 min·sample-1) of water dilution through linear (R2 ≥ 0.984) and exponential fitting (R2 ≥ 0.992); Electrochemistry enables detection (6 min·sample-1, R2 ≥ 0.979) of the adulteration of yolk ratio in whole egg; Interfacial fingerprinting technique effectively detects (detection duration: 10 min·sample-1, detection limit: 1.0-10.0 wt%) the adulteration of different varieties of egg white. Subsequently, through 3D-fluorescence microscopy (interface height variation: 22.49-573.45 μm), interfacial tension variation (65.54-35.48 mN·m-1), contact angle variation (89.7°-32.9°), particle size range (free water: 0.94-14.29 μm; protein aggregation: 6.57-10.76 μm), and etc., interfacial fingerprinting mechanism was elucidated. This research contributes novel insights into the detection of adulteration in liquid eggs.

Integrated landscape of chicken egg chalaza proteomics

Chicken egg chalaza (CLZ) is a natural colloidal structure in eggs that exists as an egg yolk stabilizer and is similar in composition to egg white. In this study, the proteome, phosphoproteome, and N-glycoproteome of CLZ were characterized in depth. We hydrolyzed the CLZ proteins and enriched the phosphopeptides and glycopeptides. We identified 45 phosphoproteins and 80 N-glycoproteins, containing 59 phosphosites and 203 N-glycosylation sites, respectively. Typically, the ovalbumin in CLZ was both phosphorylated and N-glycosylated, with 4 phosphosites and 4 N-glycosylation sites. Moreover, we identified 2 N-glycosylated subunits of ovomucin, mucin-5B and mucin-6, with 32 and nine N- glycosylation sites, respectively. Analysis of the phosphorylation and N-glycosylation status of CLZ proteins could provide novel insights into the structural and functional characteristics of CLZ.

Differential proteomics between unhatched male and female egg yolks reveal the molecular mechanisms of sex-allocation and sex-determination in chicken

There is a huge demand to identify the sex of unhatched fertilized eggs for laying industry and to understand the differences between male and female eggs as early as possible. Then the molecular mechanisms of sex determination and sex allocation in chicken were revealed. Therefore, TMT proteomic was applied to characterize the variation of molecular matrix between unhatched male and female egg yolks. A total of 411 proteins were identified and 35 differentially expressed proteins (DEPs), including 375332005, 015809562, 763550308 (upregulated, UPs) and 1337178851, 89000557, 89000581 (downregulated, DPs), etc. were confirmed between them. Gene ontology analyses showed that DEPs were mainly involved in response to stimulus, distributed in the extracellular region and participated in binding; KEGG analyses showed that few DPs were participated in cell growth and death, transport and catabolism, signaling molecules, interaction and were enriched in ubiquitin mediated proteolysis, endocytosis, ferroptosis, etc. metabolic pathways. Moreover, most of the DEPs and related metabolic pathways were associated with sex hormones. More importantly, this study supports maternal sex-allocation theory and extends our understanding of the molecular mechanism of sex determination and differentiation in avian. Which also provides a powerful evidence for ovo sexing of unhatched fertilized domestic chicken eggs by nondestructive approach and will be of great significance to eggs processing and production.

Integrated proteomic, phosphoproteomic, and N-glycoproteomic analyses of the longissimus thoracis of yaks

Yaks (Bos mutus) live in the Qinghai–Tibet plateau. The quality of yak meat is unique due to its genetic and physiological characteristics. Identification of the proteome of yak muscle could help to reveal its meat-quality properties. The common proteome, phosphoproteome, and N-glycoproteome of yak longissimus thoracis (YLT) were analyzed by liquid chromatography-tandem mass spectrometry-based shotgun analysis. A total of 1812 common proteins, 1303 phosphoproteins (3918 phosphorylation sites), and 204 N-glycoproteins (285 N-glycosylation sites) were identified in YLT. The common proteins in YLT were involved mainly in myofibril structure and energy metabolism; phosphoproteins were associated primarily with myofibril organization, regulation of energy metabolism, and signaling; N-glycoproteins were engaged mainly in extracellular-matrix organization, cellular immunity, and organismal homeostasis. We reported, for the first time, the “panorama” of the YLT proteome, specifically the N-glycoproteome of YLT. Our results provide essential information for understanding post mortem physiology (rigor mortis and aging) and the quality of yak meat.

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A total of 2650 proteins were identified in yak longissimus thoracis.

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Common proteins were involved mainly in myofibril structure and energy metabolism.

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Phosphoproteins were associated with myofibrils, energy metabolism, and signaling.

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N-glycoproteins were engaged mainly in ECM organization, immunity, and homeostasis.

Effect of partial substitution of sodium salt on the quality of salted quail eggs

To improve the quality of salted quail eggs and solve the problem of excessive sodium content in salted eggs, we selected substitutes (K₂ CO₃ , CaCl₂ , MgCl₂ , ZnCl₂ , and FeC₆ H₅ O₇ ) to partially replace NaCl and study its effect on water migration, physicochemical properties, and textural characteristics. The low-field nuclear magnetic resonance technology (LF-NMR) was used to qualitatively analyze the moisture and proton content of quail eggs during the pickling process. The results showed that the relaxation curves of ZnCl₂ and FeC₆ H₅ O7 groups were significantly different from those of other groups. The bound water content of the ZnCl₂ group increased significantly, and FeC₆ H₅ O₇ made the binding degree of water closer. The Na⁺ of different substitute groups was determined by atomic absorption spectrometry; it was found that the permeation rate of NaCl in the curing process was in the following order: K₂ CO₃ > control group > MgCl₂ > FeC₆ H₅ O₇ > CaCl₂ > ZnCl₂ . Through the electronic tongue study and comparing the ripening period of salted quail eggs, it was found that the flavor and ripening time of salted quail eggs cured by ZnCl₂ and FeC₆ H₅ O₇ were not suitable for low-sodium pickling preparation. At the same time, CaCl₂ and MgCl₂ were suitable for low-sodium pickling and could improve the product quality. When using K₂ CO₃ , the substitution ratio can be reduced and two or more compound-curing agents can be formed with CaCl₂ and MgCl₂ , thus reducing the content of sodium salt in salted eggs. PRACTICAL APPLICATIONS: We simulated the metallic elements contained in the traditional black ash-salted eggs and salt mud coatings. By partial substitution of sodium chloride (NaCl) with different metal salts (K₂ CO₃ , CaCl₂ , MgCl₂ , ZnCl₂ , and FeC₆ H₅ O₇ ), we studied the effects of these metal salts on the physical and chemical properties, texture, and microstructure of quail eggs during the pickling process. Several suitable low-sodium substitutes were screened out to provide a theoretical foundation for the process optimization of low-sodium-salted quail eggs.

A puzzle piece of protein N-glycosylation in chicken egg: N-glycoproteome of chicken egg vitelline membrane

The chicken egg vitelline membrane (CEVM) is an important structure for the transmembrane transport of egg yolk components, protection of the blastodisc, and separation of egg white and egg yolk. In this study, the N-glycoproteome of the CEVM was mapped and analyzed in depth. Total protein of the CEVM was digested, and the glycopeptides were enriched by a hydrophilic interaction liquid chromatography microcolumn and identified by nano liquid chromatography/tandem mass spectrometry. A total of 435 N-glycosylation sites on 208 N-glycoproteins were identified in CEVM. Gene Ontology enrichment analysis showed that CEVM N-glycoproteins are mainly involved in the regulation of proteinases/inhibitors and transmembrane transport of lipids. Mucin-5B is the primary N-glycoprotein in the CEVM. Comparison of the main N-glycoproteins between the CEVM and other egg parts revealed the tissue specificity of N-glycosylation of egg proteins. The results provide insights into protein N-glycosylation in the chicken egg, CEVM functions and underlying mechanisms.