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Dipeptidyl peptidase-IV (DPP-IV) inhibitory peptides exhibit great potential to alleviate type II diabetes. This study aimed to prepare, identify and explore the molecular mechanism of DPP-IV inhibitory peptides from eggshell membrane (ESM), an abundant byproduct of the food industry, based on combining in silicoand in vitroassessments. In silicoevaluation of ten major ESM proteins revealed the great potential of ESM as a novel source of DPP-IV inhibitors. Moreover, the optimal combined-enzymatic strategy (alkaline protease + papain) for the efficient production of DPP-IV inhibitory peptides from ESM was designed by simulated proteolysis. Corresponding with in silicopredictions, in vitroassessments confirmed that sodium sulfite assisted the screened dual enzymes led to better production of DPP-IV inhibitory peptides from ESM, with preferable total nitrogen recovery (86.61% ± 4.83%), DPP-IV inhibitory activity (64.61% ± 2.75%) and total antioxidant activity (215.27 ± 1.75 μg/mL). Due to the correlation between diabetes and oxidative stress, the antioxidant and DPP-IV inhibitory activities of the hydrolysate facilitate its amelioration of diabetes. Three novel DPP-IV inhibitory peptides with high abundance in ESM hydrolysates (YPEPPPQ, HDGADVS and VTDGQPH) were identified by LC-MS/MS, in silicocharacterization and molecular docking. These peptides were synthesized and confirmed to possess DPP-IV inhibitory activity, potentially relating to their stable binding with key residues within the S1, S2 pockets and catalytic triad of DPP-IV via hydrogen bonding and hydrophobic interaction. Overall, this research suggests an effective and time-saving strategy to investigate novel DPP-IV inhibitory peptides from ESM, as well as opens new opportunities for ESM application in antidiabetic foods.

Dihydromyricetin (DHM), as a bioactive flavanonol compound, is mainly found in “Tengcha” (Ampelopsis grossedentata) cultivated in south of China. This study aimed to investigate the anti-hyperglycemic and anti-dyslipidemic activities of DHM using type 2 diabetes mellitus (T2D) rats, which was induced by feeding with high fat and fructose diet for 42 days and intraperitoneal administration of streptozocin. Forty-eight freshly-weaned rats were randomly assigned into the negative control (Blank), low dose (100mg/kg), medium dose (200mg/kg), high dose (400mg/kg), and positive (40mg/kg, met) groups. Fasting blood glucose and body weight were measured at weekly interval. Oral glucose tolerance tests were performed on days 42. The results revealed that DHM possessed significant antihyperglycaemic and antihyperinsulinemic effects. Moreover, after the DHM treatment, p-Akt and p-AMPK expression was upregulated, and glycogen synthase kinase-3β (GSK-3β) expression was downregulated, indicating that the potential anti-diabetic mechanism of DHM might be due to the regulation of the AMPK/Akt/GSK-3β signaling pathway.

Background: Collagenase is a type of proteolytic enzyme that specifically hydrolyzes native collagen with a three-dimensional helical structure. The structure and properties of collagenase vary with different sources and types. In addition to the well-characterized Clostridiumcollagenase, other collagenases are largely unknown. Various gene and protein databases have been widely used to mine novel functional genes in the genome. Gene mining and sequence analysis are effective methods for studying these enzymes. Objective: The present study aimed to understand the molecular, structural, and functional characteristics of collagenase from Bacillus cereusMH19 using a bioinformatics approach. Methods: Based on the three-generation sequencing PacBio technique, Sequencing the Bacillus cereusMH19 genome. Function annotation is completed by blasting genes with different databases. Collagenases were investigated based on the physiochemical properties, phylogenetic relation, and domain architecture. The 3D structure model of the selected collagenase has been constructed and verified by SAVES. Results: There were 5 collagenases in Bacillus cereusMH19 with a molecular weight distribution ranging from 36-110 kDa. The analysis of evolutionary relationship between different collagenases indicating that the BCC000504 and BCC003388 collagenase gene sequences are closer to the typical collagenase genes ColG, ColA, and ColH, followed by BCC003615. The domain and function analysis showed that the collagenases BCC000504 and BCC003388 were similar to the collagenases ColG, ColA and ColH. BCC004271 was similar to BCC004272, and BCC003615 might be quite different from other collagenases. The secondary structure of collagenase was analyzed. The SAVES evaluation indicates that 3D structural modeling of the selected collagenase is acceptable. Conclusion: This study provides an overview of the molecular, functional, and structural characteristics of collagenase from Bacillus cereusMH19, which helps to understand the bacterial collagenase. The characterization of the collagenase will certainly expand the application range of collagenase.

Preserved egg, a traditional Chinese egg product, is regarded as an anti-inflammatory food in traditional Chinese medicine. This study was aimed to examine anti-inflammatory effect of the simulated gastrointestinal digestive products of whole preserved egg (DWPE), preserved egg white (DPEW), and preserved egg yolk (DPEY) on lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The results demonstrated that DWPE, DPEW, or DPEY inhibited the LPS-induced secretion of Nitric oxide (NO), without marked cytotoxicity. The DWPE, DPEW, and DPEY significantly suppressed the secretion of pro-inflammatory cytokines, such as tumor necrosis factor (TNF)-α and interleukin (IL)-6. Particularly, the inhibition rate of DPEW on NO, IL-6, and TNF-α could reach 25 to 27%, 31 to 42%, and 26 to 38%, respectively (P <0.05). Furthermore, the DPEW and DPEY downregulated the gene expression of Cyclooxygenase-2 and inducible nitric oxide synthase in a dose-dependent manner. Taken together, this study indicated that DWPE, DPEW, and DPEY, especially DPEW, might serve as functional food for anti-inflammatory therapy.

In the present study, we investigated the effect of galangal extract on the lipid oxidation, antioxidant activity and fatty acid composition of salted duck eggs. Three groups of salted duck eggs were comparatively assessed: salted duck egg enriched with 0.1% and 0.5% (w/v) of galangal extract and salted duck egg without galangal extract as a control. Results showed that galangal extract significantly reduced 2-thiobarbituric acid reactive substances from 1.60 mg MDA kg−1to 1.07 mg MDA kg−1and anisidine values from 67.55 to 53.64 at the end of salting time, moreover, decrease in the levels of conjugated dienes were also noticed from 0.018 to 0.007% during the salting time compared to the control group. Furthermore, galangal extract along with salting time also had significant effects on the fatty acid composition. Oleic acid, followed by palmitic acid and margaric acid, were the predominant fatty acids found in salted duck eggs supplemented with galangal extract after 14 days of salting process. Results of DPPH-scavenging activity indicated that salted duck eggs supplemented with 0.5% (w/v) galangal extract had significantly higher antioxidant activity (p< 0.05) than control at 28th day of salting. Further, analysis of electronic nose revealed that the addition of galangal extract could provide unique flavor to salted eggs during the curing process.

In order to broaden the antimicrobial action spectrum of lysozyme against Gram-negative bacteria, different partially reduced lysozyme derivatives were obtained by reducing the R-S-S-R bonds of lysozyme using the reducing agent Na2SO3. The circular dichroism behavior analysis showed that the tertiary structure of the partially reduced lysozyme molecules became more flexible, leading to an obvious increase in the surface hydrophobicity and the tryptophan fluorescence intensity. Zeta potential analysis indicated that the introduction of SO32−led to a decrease in the surface charges of the reduced lysozyme molecules. Compared with the native lysozyme, the reduced lysozymes not only showed a 1 log increase in the antimicrobial activity against Escherichia coliATCC 25922 and Salmonella enteritidisATCC 13076 (P<0.05), but also maintained nearly the same antimicrobial activity against Staphylococcus aureusATCC 29213 (P>0.05). Overall, the reductive modification with the food-friendly, compatible, and safe reducing agent Na2SO3has broadened the antimicrobial action spectrum of the modified lysozymes against Gram-negative bacteria, with the enhancement extent depending on the reduction degree and the type of bacterial strains. The integrated results suggest that the Na2SO3-reduced lysozyme can be used as a novel safe potential bactericidal additive for food-processing industry.

Posttranslational N-glycosylation of food proteins plays a critical role in their structure and function. However, the N-glycoproteome of chicken egg yolk (CEY) has not been studied yet. Glycopeptides hydrolyzed from CEY proteins were enriched, with deglycosylation occurring using PNGase F, and then were identified using a shotgun glycoproteomics strategy. A total of 217 N-glycosylation sites and 86 glycoproteins were identified in CEY, and these glycoproteins are mainly involved in the binding, biological regulation, catalytic activity, and metabolic processes. Among the identified CEY glycoproteins, 22 were recognized as proteases and protease inhibitors, suggesting that a proteinase/inhibitor regulation system exists in CEY; further, 15 were members of the complement and immune systems, which provide protection against potential threats during hatching. The study provides important structural information about CEY glycoproteins and aids in the understanding of the underlying mechanism of embryo development as well as changes in CEY functional characteristics during storage and processing.

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.

A reliable method for the simultaneous determination of aflatoxins B1, G1, B2, G2, zearalenone and its metabolites α-zearalanol and β-zearalanol was developed. Mycotoxins have been extracted from eggs using a QuEChERS-based extraction procedure (quick, easy, cheap, effective, rugged and safe) followed by applying C18 and a PSA further clean-up step, then detection by ultra high performance liquid chromatography (UPLC) coupled to tandem mass spectrometry (MS/MS) using an electrospray–ionization interface (ESI) in both positive and negative ion modes. Matrix-matched calibration was used for quantification in order to reduce the matrix effect. Validation of the method was carried out in eggs by recovery experiments. Recoveries of the spiked samples were in the range between 84.8 and 114.6% with an intra-day relative standard deviation lower than 20.7% and an inter-day relative standard deviation lower than 18.2%. Limits of quantification (LOQ) ranged from 3.0–15.0 μg kg−1. The developed method was successfully applied to the analysis of eggs and a positive sample which was contaminated by AFB1 was detected.

An attempt was made to develop a new protocol for preparing phosvitin that could be easy scaled up using polyethylene glycol (PEG6000). Influence of PEG6000 concentration and pH of sample solution on phosvitin isolation was investigated. Phosvitin of high purity (99%) was obtained in good yield (47%) with the optimal condition of pH 4.0 and 3% PEG6000 precipitation. In addition, through evaluating different anion‐exchange chromatography methods, the DEAE procedure at pH 7.5 was finally selected as the best procedure to obtain metal‐free phosvitin that lost the least protein. Furthermore, it is observed that the purity and characterizations of prepared phosvitin were similar to those of the standard phosvitin from Sigma, and the random coil of phosvitin converted into more compact structure after removing metal ion. In conclusion, the developed method was simple and suitable for scaled up preparation of phosvitin.

Duck eggs are nutritious and healthy diet and their properties further increased after being preserved by alkaline treatments. Preserved eggs are widely used as functional food products most probably as an alkalescent food posing several benefits to human health. An alkaline treatment increased their functional properties as a functional food ingredient, as well as their anti-inflammatory and anti-cancer properties are also enhanced. This review was aimed to accumulatively review functional properties of preserved eggs as an excellent food ingredient and as an excellent anti-inflammatory food. Hence, we have deeply reviewed the functional properties of preserved eggs as a functional food product with emphasis on their improved functional properties while preservation. Furthermore, we have given deep insights into rationale for alkaline pH in cell and cancer microenvironment in order to get better understanding about the health benefits of alkalescent food. At last, the detailed knowledge about anti-inflammatory and anti-cancer role of preserved eggs as an alkalescent food has been discussed at cellular level which made us aware of its importance for regular intake in our daily life for better health. However, there is still a lack of knowledge about this aspect in the research field and might rarely reviewed; hence this review will be promising in providing deep insights and further ideas for research conductance.

Renal cell carcinoma (RCC) is a lethal genitourinary cancer and accounts 3% of total cancers worldwide. Various pleiotropic cytokines, i.e activator of signal transducer and activator of transcription 3 (STAT3), Cellular FLICE (FADD-like IL-1β-converting enzyme)-inhibitory protein (c-FLIP) and interleukin-6 (IL-6) could act to block the process of apoptosis in renal cancinoma cells, trigering its growth and proliferation. Their over-expression could activate several anti-apoptotic factors, hence it is important to block or down-regulate such factors in order to activate apoptosis in cancer cells. Up till now, several chemo and radiotherapies are being considered to combat renal carcinoma cells; however, there is a strong need to get some dietary therapeutic treatment. Hence, this study has used gastrointestinal digests of preserved eggs (GID-PE) for the apoptosis of Caki-1, ACHN and 786-O cells lines, in order to get insights about apoptosis in their mitochondrial pathway before and after treatment with (GID-PE). Moreover, changes in morphology accompanied by apoptosis analysis with different treatments have been carried out. Furthermore, ELISA analysis and mRNA expression of certain pro-inflammatory and anti-inflammatory cytokines were determined before and after treatment with GID-PE. Furthermore, the specific anti-apoptotic genes, i.e cFlip, Mcl-1, Bcl-XL and STAT3 were examined for their down-regulated expression after different treatments with GID-PE. Moreover, Bax expression acting as a pro-apoptotic gene was up-regulated up to some extent after treatments with GID-PE. Hence, GID-PE was confirmed to give anti-inflammatory effects in renal carcinoma cells could be used as health beneficial food product with anti-cancer properties.

As two major proteins of egg white, the interaction between lysozyme (LYZ) and ovalbumin (OVA) has been studied. In the present research, the mechanism and kinetics of the interaction between LYZ and OVA were studied using several methods, including cyclic voltammetry (CV), dual polarization interferometry (DPI) and surface plasmon resonance (SPR), and the effect of their interaction on the activity of LYZ was investigated using a bacteriolytic activity assay. Cyclic voltammograms showed that there was an interaction between these two proteins. DPI results indicated that the interaction is a type of chimeric mode, and the KAand KDof the interaction were 498 and 2.01 × 10−3 mol/L, respectively, calculated from the fitting of the surface plasmon resonance curve. The bacteriolytic activity assay showed that the interaction between these two proteins reduced the bacteriolytic activity of LYZ.

Preserved eggs are a type of egg products made from duck eggs and have anti-inflammatory activity. The purpose of this study was to investigate the effects of preserved egg simulated gastrointestinal digests on the apoptosis of HT29 and HepG2 cells. The cells morphology, apoptosis and apoptosis associated genes (Bcl-2, Bax, COX-2) and proteins (caspase-3 and caspase-9) were evaluated. The results showed that preserved egg digests significantly up regulated the expression of genes Bax, caspase-3 and caspase-9, which are involved in cell apoptosis, and up regulated the expression of the pro-apoptotic factors Bcl-2 and COX-2 both in HT29 and HepG2 cells, leading to a reduction in the ratio of Bcl-2:Bax proteins. The results also showed that the apoptosis of HT29 and HepG2 cells was promoted by the PED in a dose-dependent manner. Thus, PED may serve as a potential functional food for cancer treatment.

Obesity induced by consuming a high-fat diet (HFD) is a major risk for nonalcoholic fatty liver disease, which has become a worldwide health problem. To study the effects of high-density lipoproteins of egg yolk (EYHDL) on mice with HFD induced obesity, lipidomic analyses using ultra performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) was done with serum and liver samples on 60 and 100 days. The results showed that EYHDL significantly alleviated mouse obesity by decreasing adipose tissue accumulation, serum low-density lipoproteins cholesterol, total cholesterol, hepatic triglycerides and development of hepatic steatosis. The EYHDL group was separated from HFD on the orthogonal partial least squares-discriminant analysis score plots, suggesting the beneficial effect of EYHDL on dyslipidemia in obese mice. Volcano plots combined with S-plots showed that the potential biomarkers contributing to these differences were diglycerides, phosphatidylcholines, phosphatidylinositols and lysophosphatidylcholines. On the basis of these biomarkers, glycerophospholipid metabolism is probably the main pathway regulated by EYHDL in obese mice. In summary, EYHDL alleviated hyperlipidemia in obese mice by regulating the phosphatidylcholines and neutral glycerolipids composition, and the lipid biomarkers can be used to better assess the mechanism and therapy for HFD-induced obesity.

BackgroundSoluble eggshell membrane protein (SEP) has been proved to hold the antioxidant activity. The functional role of SEP on cardioprotection was investigated in vivoand in vitro.MethodsRats and cardiomyocytes were pretreated with SP2, a hydrolysate attained from SEP, and then subjected to ischemia/reperfusion (I/R) or hypoxia/reoxygenation (H/R) and hydrogen peroxide, respectively. The measurement of myocardial infarct size, cell apoptosis assay, cell viability assay, and caspase activity assay were performed on rats and cardiomyocytes.ResultsThe results showed that the treatment of SP2 induced the resistance to I/R or H/R injury on rats and cardiomyocytes as indicated by decreased infarct size and decreased cellular apoptosis. The cardioprotective roles of SP2 were partly resulted from the downregulated expression and activity of caspase-3 in which the effect was similar to the caspase inhibitor, z-VAD-fmk, and could be rescued by caspase activator, PAC-1.ConclusionsThis investigation has demonstrated that SP2 attenuated the damage of I/R and H/R on rats and cardiomyocytes by the caspase-dependent pathway. This cardioprotective effect of SP2 suggested a novel therapeutic agent of SEP for ischemic-related heart diseases.