ABSTRACT
Probiotic intervention is an effective strategy to alleviate oxidative stress-related diseases. Our previous studies found that Lactiplantibacillus plantarum NJAU-01 (NJAU-01) exhibited antioxidant effects in a D-galactose (D-gal)-induced aging mouse model. However, the underlying mechanism remains to be unveiled. This study was aimed to investigate the ameliorative effect and mechanism of NJAU-01 against oxidative stress induced by D-gal. The results showed that NJAU-01 could reverse the tendency of a slow body weight gain induced by D-gal. NJAU-01 relieved hepatic oxidative stress via increasing the hepatic total antioxidant capacity and antioxidant enzyme activities including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT). Moreover, the malondialdehyde (MDA) level was reversed after NJAU-01 supplementation. The proteomic results showed that there were 201 differentially expressed proteins (DEPs) between NJAU-01 and D-gal groups. NJAU-01 regulated the expressions of glutathione S-transferase Mu 5 (Gstm5), glutathione S-transferase P2 (Gstp2) and NADH dehydrogenase 1α subcomplex subunit 7 (Ndufa7) related to oxidative stress, and autophagy protein 5 (Atg5) and plasma alpha-L-fucosidase (Fuca2) involved in autophagy, etc. 16S rDNA sequencing results showed that NJAU-01 supplementation could regulate the gut microbiota dysbiosis induced by D-gal via increasing the relative abundances of the phylum Firmicutes and the genus Lactobacillus and reducing the relative abundances of the phylum Bacteroidetes and the genera Lachnospiraceae_NK4A136_group as well as Prevotellaceae_UCG-001, etc.. Spearman correlation analysis results showed that the altered gut microbiota composition had a significant correlation with antioxidant enzyme activities and the DEPs related to oxidative stress. Overall, NJAU-01 alleviated hepatic oxidative stress induced by D-gal via manipulating the gut microbiota composition and hepatic protein expression profile.
Subject(s)
Galactose , Gastrointestinal Microbiome , Liver , Oxidative Stress , Probiotics , Proteomics , Oxidative Stress/drug effects , Animals , Gastrointestinal Microbiome/drug effects , Mice , Probiotics/pharmacology , Probiotics/administration & dosage , Liver/drug effects , Liver/metabolism , Male , Lactobacillus plantarum , Antioxidants/pharmacology , Malondialdehyde/metabolism , Superoxide Dismutase/metabolismABSTRACT
The direct conversion of methane to methanol has attracted increasing interest due to abundant and low-cost natural gas resources. Herein, by anchoring Cr-oxo/-oxyhydroxides on UiO-66 metal-organic frameworks, we demonstrate that reactive anionic oxyl radicals can be formed by controlling the coordination environment based on the results of density functional theory calculations. The anionic oxyl radicals produced at the completely oxidized CrVI site acted as the active species for facile methane activation. The thermodynamically stable CrVI-oxo/-oxyhydroxides with the anionic oxyl radicals catalyze the activation of the methane C-H bond through a homolytic mechanism. An analysis of the results showed that the catalytic performance of the active oxyl species correlates with the reaction energy of methane activation and H adsorption energies. Following methanol formation, N2O can regenerate the active sites on the most stable CrVI oxyhydroxides, i.e., the Cr(O)4Hf species. The present study demonstrated that the anionic oxyl radicals formed on the anchored CrVI oxyhydroxides by tuning the coordination environment enabled facile methane activation and facilitated methanol production.
ABSTRACT
The inoculation fermentation technology was applied to the processing of dried cured goose to investigate the protein degradation. Lactobacillus fermentum (L), Staphylococcus epidermidis (S) and mixed strains (L + S) were individually inoculated into the whole goose before drying. We studied the degradation of protein in the air-dried period of goose. The results showed that compared with natural fermentation, inoculation fermentation significantly increased the content of non-protein nitrogen (14.85 mg/g NPN), proteolysis index (8.98% PI), myofibril fragmentation index (89.35 MFI) and total amount of free amino acids (1332.6 mg/g FAA) of dried cured goose. Electrophoresis revealed that the inoculation fermentation accelerated the degradation of macromolecular proteins and the accumulation of small molecular proteins. The degree of protein degradation in four groups of goose was in an order of L + S group > S group > L group > CK group. It suggested that inoculation fermentation could promote the degradation of myofibrillar proteins.
Subject(s)
Limosilactobacillus fermentum , Animals , Proteolysis , Fermentation , Staphylococcus epidermidis , GeeseABSTRACT
The objective of this study was to investigate the effect of pork oxidation through modified atmosphere packaging (MAP) on gel characteristics of myofibrillar proteins (MP) during the heat-induced gelation process. The pork longissimus thoracis (LT) was treated by MAP at varying oxygen concentrations (0, 20, 40, 60, and 80% O2) with a 5-day storage at 4 °C for the detection of MP oxidation and gel properties. The findings showed the rise of O2 concentration resulted in a significant increase of carbonyl content, disulfide bond, and particle size, and a decrease of sulfhydryl content and MP solubility (p < 0.05). The gel textural properties and water retention ability were significantly improved in MAP treatments of 0-60% O2 (p < 0.05), but deteriorated at 80% O2 level. As the concentration of O2 increased, there was a marked decrease in the α-helix content within the gel, accompanied by a simultaneous increase in ß-sheet content (p < 0.05). Additionally, a judicious oxidation treatment (60% O2 in MAP) proved beneficial for crafting dense and uniform gel networks. Our data suggest that the oxidation treatment of pork mediated by O2 concentration in MAP is capable of reinforcing protein hydrophobic interaction and disulfide bond formation, thus contributing to the construction of superior gel structures and properties.
ABSTRACT
This research aims to investigate the effect of different ultrasonic powers cooking on the quality of pork meatballs. Pork meatballs treated with ultrasound-assisted cooking at 450 W had the most uniform and smooth structures displayed by scanning electron microscopy. Furthermore, with increasing ultrasonic powers, the water retention capacity of pork meatballs first increased and then decreased, compared with the non-ultrasound group, when the ultrasonic power was 450 W, the cooking yield of pork meatballs increased from 82.55% to 92.87%, and the centrifugal loss decreased from 25.35% to 11.52%. Additionally, ultrasound-assisted cooking had a positive effect on the moisture migration, tenderness, and sensory property of pork meatballs, and 450 W sample exhibited the highest overall acceptability score (P < 0.05). In conclusion, the physicochemical properties and microstructure of pork meatballs could be improved by appropriate ultrasonic power, and ultrasonic technology was considered as an effective processing method for improving the quality of meat products.
Subject(s)
Meat Products , Pork Meat , Red Meat , Animals , Swine , Cooking/methods , Meat Products/analysisABSTRACT
Three kinds of phenolic acids: ferulic acid (FA), caffeic acid (CA), and gallic acid (GA) with different chemical structures were individually grafted onto Arabic gum (AG) via a laccase mediated method, and their roles in stabilizing o/w emulsions were evaluated. The total phenolic content in modified AG increased from 2.7 ± 0.2 to 18.7 ± 0.2, 19.8 ± 0.6, 22.4 ± 0.8 mg/g after 4 h of laccase catalysis, respectively. FTIR spectra of modified AGs exhibited additional phenolic characteristics, revealing the successful grafting of phenolic acids to AG structure. Compared with natural AG, modified AGs showed remarkably enhanced thermal stability, as well as antioxidant capacity in an order of gallic acid > caffeic acid > ferulic acid. The incorporation of phenolic acids into AG dramatically improved its emulsification performance. Herein, gallic acid-modified AG evinced up to 17.6 % and 12.6 % increments in emulsifying activity and emulsion stability relative to natural AG, respectively. Moreover, the oxidative stability of AG emulsions was pronouncedly meliorated by the introduced phenolic acids, especially gallic acid, as manifested by the suppressed production of primary and secondary oxidation products.
ABSTRACT
Converting CO2 to valuable chemicals through a variety of thermal, photo-, and electro-catalytic reaction processes will reduce the net CO2 emission and contribute positively to the "net-zero" goal. C1 and C2 products are important chemical feedstocks and can be produced from the effective catalytic conversion of CO2. The key to developing effective CO2 conversion catalysts is an understanding of CO2 interaction and the elementary bond-breaking and formation steps on the active catalysts. Over the past two decades, density functional theory-based approaches have enabled both mechanistic understanding and catalyst design for CO2 activation and conversion. In this article, we review our recent effort in understanding the mechanism of CO2 activation and conversion, focusing on the unique role of the metal/metal oxide interfaces in both thermal and electrochemical catalytic CO2 reduction. We showed that In2O3-based catalysts exhibited a uniquely high methanol selectivity while suppressing CO formation from the reverse water-gas shift reaction. We have also demonstrated that the metal/metal-oxide interfaces can be tuned by selecting an appropriate metal and metal oxide to optimize its activity and selectivity for both thermal- and electro-catalytic reduction of CO2. The oxophilicity of the metal in the metal oxide can be used as a qualitative measure for determining the selectivity towards CH3OH or CH4 in the electro-catalytic reduction of CO2. The studies demonstrated the impact of the density functional theory-based atomic-level approaches in unravelling the reaction mechanism and predicting highly efficient catalysts and catalytic systems.
ABSTRACT
This study aims to assess and compare the influences of different heating methods on the quality characteristics of pale, soft, and exudative (PSE)-like and normal (NOR) pectoralis major through quantitative proteomic analysis. A total of 632 proteins were identified, and there were 84, 89, 50, and 43 differentially abundant proteins (DAPs) between processed PSE and NOR samples after four thermal treatments, including boiling (BO), steaming (ST), roasting (RO), and microwaving (MV), respectively, where moist heating conditions led to more different protein abundance. Processed PSE muscles resulted in significant changes in structural proteins related to myofibrillar and connective tissue, which could be associated with their structural instability and degraded quality. Collagen, tropomyosin, myoglobin, and hemoglobin could be potential indicators of PSE muscles color stability and variation during thermal processing. The quantitative proteomic analysis will help correlate molecular changes with processed meat quality towards future optimization of PSE poultry meat processing.
Subject(s)
Pectoralis Muscles , Proteomics , Animals , Heating , Chickens , Meat/analysis , MyoglobinABSTRACT
This study aimed to investigate the time-course effect of Lactobacillus plantarum NJAU-01 in scavenging exogenous hydrogen peroxide (H2O2). The results showed that L. plantarum NJAU-01 at 107 CFU/mL was able to eliminate a maximum of 4 mM H2O2 within a prolonged lag phase and resume to proliferate during the following culture. Redox state in the start-lag phase (0 h, without the addition of H2O2), indicated by glutathione and protein sulfhydryl, was impaired in the lag phase (3 h and 12 h) and then gradually recovered during subsequent growing stages (20 h and 30 h). By using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and proteomics analysis, a total of 163 proteins such as PhoP family transcriptional regulator, glutamine synthetase, peptide methionine sulfoxide reductase, thioredoxin reductase, ribosomal proteins, acetolactate synthase, ATP binding subunit ClpX, phosphoglycerate kinase, UvrABC system protein A and UvrABC system protein B were identified as differential proteins across the entire growth phase. Those proteins were mainly involved in H2O2 sensing, protein synthesis, repairing proteins and DNA lesions, amino sugar and nucleotide sugar metabolism. Our data suggest that biomolecules of L. plantarum NJAU-01 are oxidized to passively consume H2O2 and are restored by the enhanced protein and/or gene repair systems.
Subject(s)
Lactobacillus plantarum , Lactobacillus plantarum/metabolism , Hydrogen Peroxide/pharmacology , Proteomics , Oxidation-Reduction , Bacterial Proteins/geneticsABSTRACT
Effects of the incorporation of ultrasound with varied intensities (0-800 W) into the thermal-induced gelation process on the gelling properties of myofibrillar protein (MP) were explored. In comparison with single heating, ultrasound-assisted heating (<600 W) led to significant increases in gel strength (up to 17.9%) and water holding capacity (up to 32.7%). Moreover, moderate ultrasound treatment was conducive to the fabrication of compact and homogenous gel networks with small pores, which could effectively impair the fluidity of water and allow redundant water to be entrapped within the gel network. Electrophoresis revealed that the incorporation of ultrasound into the gelation process facilitated more proteins to get involved in the development of gel network. With the intensified ultrasound power, α-helix in the gels lowered pronouncedly with a simultaneous increment of ß-sheet, ß-turn, and random coil. Furthermore, hydrophobic interactions and disulfide bonds were reinforced by the ultrasound treatment, which was in support of the construction of preeminent MP gels.
Subject(s)
Muscle Proteins , Myofibrils , Muscle Proteins/chemistry , Hydrophobic and Hydrophilic Interactions , Gels/chemistry , Myofibrils/chemistry , Water/chemistryABSTRACT
Starch-stabilized Pickering emulsions were employed as a novel particulate filler in myofibrillar protein (MP)-based gels for improving the gelling characteristics. The role of emulsions prepared by native starches (NS) with distinctive crystalline types (i.e., A-type waxy corn starch, B-type potato starch, and C-type pea starch) and their OSA-modified counterparts (A-OS, B-OS, C-OS) in the gelling performance was evaluated and compared with MP-stabilized-emulsion. Compared with MP-emulsion, starch-emulsion caused substantial increases in the gelling properties, notably for OSA-starch emulsions. Herein, A-OS exhibited up to 1.26-, 5.3-, and 2.9-fold increments in storage modulus, gel strength, and water holding capacity relative to pure MP gel, respectively, higher than B-OS and C-OS. Moreover, light microscopy evinced a more compact gel network filled with smaller and uniform oil droplets when A-OS emulsions were incorporated into the gels. The addition of OSA-starch emulsions, especially A-OS emulsion, facilitated the protein conformational conversion from α-helix to ß-sheet and caused a marked reduction of free sulfhydryls in the gels; yet, the chemical forces that stabilized the gels altered, where remarkable reinforcements in hydrogen bond and hydrophobic interaction were detected, in support of the construction of splendid MP gels. Hence, OSA-starch emulsions show promise as functional components in meat products.
Subject(s)
Starch , Amylopectin , Emulsions/chemistry , Excipients , Gels/chemistry , Starch/chemistryABSTRACT
Understanding structural transformation and phase transition accompanying reactions in a solid as a catalyst or oxygen carrier is important to the design and optimization of many catalytic or chemical looping reaction processes. Herein, we combined density functional theory calculation with the stochastic surface walking global optimization approach to track the structural transformation accompanying the reduction of CuO upon releasing oxygen. We then used machine learning (ML) methods to correlate the structural properties of CuOx with varying x. By decomposing a reduction step into oxygen detachment and structural reconstruction, we identified two types of pathways: (1) uniform reduction with minimal structural changes; (2) segregated reduction with significant reconstruction. The results of ML analysis showed that the most important feature is the radial distribution functions of Cu-O at a percentage of oxygen vacancy [C(OV)] < 50% and Cu-Cu at C(OV) > 50% for CuOx formation. These features reflect the underlying physicochemical origin, i.e., Cu-O breaking and Cu-Cu formation in the respective stage of reduction. Phase diagram analysis indicates that CuO will be reduced to Cu2O under a typical oxygen uncoupling condition. This work demonstrates the complexity of solid structural transformation and the potential of ML methods in studying solid state materials involved in many chemical processes.
ABSTRACT
The changes in texture and rheological characteristics, water holding capacity, and microstructure of pork myofibrillar protein with high-pressure homogenization-modified (0-150 MPa) soy 11S globulin were studied. The cooking yield, whiteness values, texture properties, shear stress, initial apparent viscosity, storage modulus (G'), and loss modulus (Gâ³) of pork myofibrillar protein with high-pressure homogenization-modified soy 11S globulin were significantly increased (p < 0.05) compared with the sample of 0 MPa, and centrifugal yield was significantly decreased, except for the sample of 150 MPa. Therein, the sample of 100 MPa had the largest values. Meanwhile, the water and proteins bonded more tightly because the initial relaxation times of T2b, T21 and T22 from pork myofibrillar protein with high-pressure homogenization-modified soy 11S globulin were shorter (p < 0.05). Overall, the water-holding capacity, gel texture and structure, and rheological properties of pork myofibrillar protein could improve when adding soy 11S globulin treated with 100 MPa.
ABSTRACT
Electrochemical reduction of CO2 to value-added chemicals has been hindered by poor product selectivity and competition from hydrogen evolution reactions. This study aims to unravel the origin of the product selectivity and competitive hydrogen evolution reaction on [MP]0 catalysts (M = Fe, Co, Rh and Ir; P is porphyrin ligand) by analyzing the mechanism of CO2 reduction and H2 formation based on the results of density functional theory calculations. Reduction of CO2 to CO and HCOO- proceeds via the formation of carboxylate adduct ([MP-COOH]0 and ([MP-COOH]-) and metal-hydride [MP-H]-, respectively. Competing proton reduction to gaseous hydrogen shares the [MP-H]- intermediate. Our results show that the pKa of [MP-H]0 can be used as an indicator of the CO or HCOO-/H2 preference. Furthermore, an ergoneutral pH has been determined and used to determine the minimum pH at which selective CO2 reduction to HCOO- becomes favorable over the H2 production. These analyses allow us to understand the product selectivity of CO2 reduction on [FeP]0, [CoP]0, [RhP]0 and [IrP]0; [FeP]0 and [CoP]0 are selective for CO whereas [RhP]0 and [IrP]0 are selective for HCOO- while suppressing H2 formation. These descriptors should be applicable to other catalysts in an aqueous medium.
Subject(s)
Metalloporphyrins , Porphyrins , Carbon Dioxide , Hydrogen , ProtonsABSTRACT
Effects of octenylsuccinic anhydride (OSA) esterification on the morphology, crystalline structure, and emulsifying properties of three representative starches with different crystalline types, namely waxy corn starch (A-type), potato starch (B-type), and pea starch (C-type) were investigated. XRD patterns testified OSA substitution occurred principally in the amorphous region without affecting the crystalline patterns, whereas SEM verified esterification was mainly a surface phenomenon. However, OSA esterification caused a decrease in the peak intensity and area of small-angle X-ray scattering profiles, indicating the semi-crystalline lamellae ordering was impeded to a certain extent. Compared with A- and C-type starches, B-type starch had a stronger affinity for OSA, as manifested by its higher degree of substitution (DS), graver surface detriment, and depressed order of semi-crystalline lamellae. The emulsifying properties of all starches were pronouncedly improved by OSA modification, especially for A-type starch even with comparatively lower DS. Pickering emulsion stabilized by OSA-modified A-type starch (A-OSAS) with smaller droplet size and more uniform droplet size distribution exhibited more splendiferous stability relative to the other two modified starches. Moreover, rheological tests revealed A-OSAS possessed the highest apparent viscosity and storage modulus (G'), insinuating strong intermolecular interactions between starch granules at the interface and/or in the continuous phase.
Subject(s)
Starch , Amylopectin , Emulsions/chemistry , Particle Size , Starch/chemistry , ViscosityABSTRACT
Copper compounds have been extensively investigated for diverse applications. However, studies of cuprous hydroxide (CuOH) have been scarce due to structural metastability. Herein, a facile, wet-chemistry procedure is reported for the preparation of stable CuOH nanostructures via deliberate functionalization with select organic ligands, such as acetylene and mercapto derivatives. The resulting nanostructures are found to exhibit a nanoribbon morphology consisting of small nanocrystals embedded within a largely amorphous nanosheet-like scaffold. The acetylene derivatives are found to anchor onto the CuOH forming CuC linkages, whereas CuS interfacial bonds are formed with the mercapto ligands. Effective electronic coupling occurs at the ligand-core interface in the former, in contrast to mostly non-conjugated interfacial bonds in the latter, as manifested in spectroscopic measurements and confirmed in theoretical studies based on first principles calculations. Notably, the acetylene-capped CuOH nanostructures exhibit markedly enhanced photodynamic activity in the inhibition of bacteria growth, as compared to the mercapto-capped counterparts due to a reduced material bandgap and effective photocatalytic generation of reactive oxygen species. Results from this study demonstrate that deliberate structural engineering with select organic ligands is an effective strategy in the stabilization and functionalization of CuOH nanostructures, a critical first step in exploring their diverse applications.
ABSTRACT
The purpose of this study was to investigate the changes of oxidative attributes, protein DJ-1 expression, oxidized form (oxDJ-1), and cellular localization in RFN and PSE pork meat during the post-mortem aging. The longissimus thoracis of RFN and PSE groups were collected and classified by determination of pH, color and purge loss and then aged for 1, 3 and 7 d at 4 °C postmortem. Results showed that the content of DJ-1 and oxDJ-1 was continuously increased during 7 d of postmortem aging. A relatively higher protein DJ-1, oxDJ-1, oxygen reactive species and disulfide bond contents were found in PSE meat in comparison to RFN meat. Immunostaining showed that protein DJ-1 was located in cytoplasm, membrane and some nucleus of muscle cells. DJ-1 was shown to correlate with meat quality and oxidative attributes, suggesting a regulatory role in resisting oxidative stress and meat quality formation during post-mortem aging.
Subject(s)
Pork Meat , Red Meat , Animals , Meat , Muscle, Skeletal/chemistry , Oxidation-Reduction , SwineABSTRACT
Modified NiO catalysts with controllable vacancies and dopants are promising for alkene production from oxidative dehydrogenation (ODH) of light alkanes, and a molecular understanding of the modification on elementary reaction steps would facilitate the design of highly efficient catalysts and catalytic processes. In this study, density functional theory (DFT) calculations was used to map out the complete reaction pathways of propane ODH on the NiO (100) surfaces with different modifiers. The results demonstrated that the presence of vacancies (O and Ni) and dopants (Li and Al) alters the electrophilicity of surface oxygen species, which in turn affects the reactivity towards C-H bond activation and the overall catalytic activity and selectivity. The strongly electrophilic O favors a radical mechanism for the first C-H activation on O followed by the second C-H activation on O-O site, whereas weak electrophilic O favors concerted C-H bond breaking over Ni-O site. The C-H bond activation proceeds through a late transition state, characterized by the almost completion of the O-H bond formation. Consequently, the adsorption energy of H adatom on O rather than p-band center or Bader charge of O has been identified to be an accurate descriptor to predict the activation barrier for C-H breaking (activity) as well as the difference between the activation barriers of propene and CH3 CCH3 (selectivity) of ODH.
ABSTRACT
Marination is a common technology in meat processing with advantages of enhancing tenderness, water retention, and overall quality. This study was conducted to investigate the effect of vacuum tumbling and immersion marination on meat quality, microstructure, water mobility, protein changes, and denaturation of Xueshan chicken. Results showed that vacuum tumbling significantly increased the marinating rate of chicken, tenderness, meat texture, and water retention. Meanwhile, vacuum tumbling decreased total sulfhydryl content alongside an increased protein surface hydrophobicity and free sulfhydryl content, indicating that vacuum tumbling elevated the degree of protein denaturation. Further, the peak area corresponding to the relaxation time T22 after vacuum tumbling was significantly higher than that of immersion marination, suggesting that the stability of the immobilized water of chicken was reduced by vacuum tumbling. Compared to immersion marination, vacuum tumbling improved myofibril fragmentation index (MFI) presenting fewer myofibrillar protein bands in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) gel and more damaged muscular cells. Overall, vacuum tumbling could improve the marination absorptivity, protein degradation, and denaturation, resulting in changes in myofibril structure and meat quality of Xueshan chicken.
ABSTRACT
Background: We aimed to analyze the predictive role of serum test and questionnaire in Early Gastric Cancer in The First Affiliated Hospital of Xingtai Medical College, Hebei Province from 2019 to 2020. Methods: In this prospective study, 280 medical examiners underwent questionnaire, serum test and gastroscopy. They were divided into Gastric cancer (GC) and Non-Gastric cancer (NGC) group. NGC group was divided into Low-grade intraepithelial neoplasia (LGIN), Chronic atrophic gastritis (CAG) and Non-chronic atrophic gastritis (NCAG) group. Results: Age, drinking, sex and Gastrin-17(G-17) was respectively independent risk factors for GC. Age, drinking and G-17 was independent risk factors for GC in men. G-17 of GC group was higher than that of LGIN and NCAG group (P<0.05). Pepsinogen I/II ratio (PGR) of GC was lower than that of NCAG group (P<0.05). There was no significant difference between Pepsinogen I (PGI) and Pepsinogen II (PGII) in the four groups. Helicobacter pylori-immunoglobulin G antibodies (H. pylori-IgG) of LGIN group was significantly higher than that of CAG and NCAG group in gastritis group (P<0.008). G-17≥42.95 pmol/L, age≥69years, male and drinking can predict GC. Conclusion: Older, drinking, men and high G-17 could respectively predict GC. Especially in men, older, drinking and high G-17 could affect the occurrence of GC. G-17, age, drinking and sex used respectively to screen high-risk populations for GC were more efficient than combined screening. GC had a higher serum G-17 and a lower PG than other gastric diseases.