The effect of sodium chloride(NaCl)curing salt content on protein oxidation,lipid oxidation and lipolysis of Chinese dry sausage was investigated.Two groups Chinese dry sausages with 2%and 4%(m/m)salt content were stu...The effect of sodium chloride(NaCl)curing salt content on protein oxidation,lipid oxidation and lipolysis of Chinese dry sausage was investigated.Two groups Chinese dry sausages with 2%and 4%(m/m)salt content were studied.The degree of protein oxidation increased during the processes in two groups sausages,while the content of phospholipids decreased,neutral lipids and free fatty acids increased.The degree of protein oxidation,lipid oxidation and lipolysis in 4%NaCl content group was higher than those in 2%NaCl content group,while 4%NaCl content group has higher lipase activity.In conclusion,4%NaCl may facilitate the protein oxidation,lipid hydrolysis and oxidation in Chinese dry sausage,and the protein oxidation had strong correlation with lipid oxidation and lipolysis.The results could provide a basis for improving the technology of industrial production.展开更多
Investigation that protein oxidation to the formation of advanced glycation end products(AGEs)after chicken myofibrillar protein glycation is limited.Models of protein oxidation induced by different concentrations of ...Investigation that protein oxidation to the formation of advanced glycation end products(AGEs)after chicken myofibrillar protein glycation is limited.Models of protein oxidation induced by different concentrations of hydroxyl radicals(·OH)were developed after the chicken myofibrillar protein mild glycation(MPG).Results exhibited that levels of AGEs and surface hydrophobicity(H_(0))steadily increased with the a ddition of h ydrogen peroxide(H_(2)O_(2))concentration.However,levels of s ulfhydryl group,free amino group,and particle size gradually decreased with the H_(2)O_(2)concentration.The protein carbonyl value increased in H_(2)O_(2)concentration until 10 mmol/L.Pearson's correlation indicated that MPG structure modification(unfolding and degradation)induced by protein oxidation were significantly positively correlated with AGEs concentration(P<0.05).Finally,a mechanism was proposed to hypothesize t he effect of protein oxidation on the formation of AGEs under MPG conditions.展开更多
Introduction: The kinetics of protein oxidation, monitored in breath, and its contribution to the whole body protein status is not well established. Objectives: To analyze protein oxidation in various metabolic condit...Introduction: The kinetics of protein oxidation, monitored in breath, and its contribution to the whole body protein status is not well established. Objectives: To analyze protein oxidation in various metabolic conditions we developed/validated a <sup>13</sup>C-protein oxidation breath test using low enriched milk proteins. Method/Design: 30 g of naturally labeled <sup>13</sup>C-milk proteins were consumed by young healthy volunteers. Breath samples were taken every 10 min and <sup>13</sup>CO<sub>2</sub> was measured by Isotope Ratio Mass Spectrometry. To calculate the amount of oxidized substrate we used: substrate dose, molecular weight and <sup>13</sup>C enrichment of the substrate, number of carbon atoms in a substrate molecule, and estimated CO<sub>2</sub>-production of the subject based on body surface area. Results: We demonstrated that in 255 min 20% ± 3% (mean ± SD) of the milk protein was oxidized compared to 18% ± 1% of 30 g glucose. Postprandial kinetics of oxidation of whey (rapidly digestible protein) and casein (slowly digestible protein) derived from our breath test were comparable to literature data regarding the kinetics of appearance of amino acids in blood. Oxidation of milk proteins was faster than that of milk lipids (peak oxidation 120 and 290 minutes, respectively). After a 3-day protein restricted diet (~10 g of protein/day) a decrease of 31% ± 18% in milk protein oxidation was observed compared to a normal diet. Conclusions: Protein oxidation, which can be easily monitored in breath, is a significant factor in protein metabolism. With our technique we are able to characterize changes in overall protein oxidation under various meta-bolic conditions such as a protein restricted diet, which could be relevant for defining optimal protein intake under various conditions. Measuring protein oxidation in new-born might be relevant to establish its contribution to the protein status and its age-dependent development.展开更多
This study investigated the protective effect of ferulic acid(FA) on the digestibility of oxidized beef myofibrillar protein(MP).MP were treated with varying concentrations of FA(20,40,and 80 μmol/g pro) and then exp...This study investigated the protective effect of ferulic acid(FA) on the digestibility of oxidized beef myofibrillar protein(MP).MP were treated with varying concentrations of FA(20,40,and 80 μmol/g pro) and then exposed to oxidation.The results showed that FA inhibited carbonyl in a dose-dependent manner.Fluorescence spectroscopy and molecular docking studies revealed FA was bonded to MP via hydrophobic interactions and hydrogen bonds.Sodium dodecyl sulfate polyacrylamide gel electrophoresis and transmission electron microscope analysis indicated that FA mitigated the aggregation of oxidized MP.Peptidomic analysis showed FA protected 34.24% peptides recover from oxidation loss,and theses recovered peptide were mainly distributed in hydrophobic regions and lysine sites.In vitro digestion showed FA remarkably improved digestibility of oxidized MP(P < 0.05),with 80 μmol/g pro FA mitigating 67.85% loss in digestibility.Overall,FA effectively preserved the release of peptides by inhibiting hydrophobic aggregation and oxidation of lysine residues,thereby alleviating the decrease in digestibility of oxidized MP.展开更多
This study systematically investigated the mechanism by which soybean peptides regulate the flavor and quality stability of infant formula nutrition powder(IFNP)during 300-day storage.The results demonstrated that soy...This study systematically investigated the mechanism by which soybean peptides regulate the flavor and quality stability of infant formula nutrition powder(IFNP)during 300-day storage.The results demonstrated that soy-bean peptide supplementation significantly improved product quality by increasing vitamin A and D retention rates by 6.24%and 15.94%respectively,enhancing dispersibility by 23.08%,and effectively mitigating color deterioration.A flavor fingerprint profile was constructed based on Gas Chromatography-Ion Mobility Spectrometry(GC-IMS)technology,and a total of 49 volatile flavor substances were identified.9 key off-flavor substances were screened out by subsequent multivariate statistical analysis.Soybean peptides significantly inhibited their accumulation,with inhibition rates reaching 46.61% for(E)-2-hexenal and 43.37% for 1-hexanal,while promoting the retention of beneficial flavor components including esters and alcohols,thereby substantially enhancing flavor stability.At the molecular level,soybean peptides exhibited remarkable antioxidant activity,reducing total free radical intensity by 6.06% through effective radical scavenging,interrupting lipid oxidation chain reactions,decreasing malondialdehyde content,and preserving unsaturated fatty acid structures.Concurrently,they significantly suppressed protein oxidative damage,as evidenced by reduced carbonyl content and maintained free sulfhydryl groups.Multivariate correlation analysis further constructed a complete quality deterioration network,confirming the synergistic relationship between lipid and protein oxidation in driving overall quality degradation.This research clarified that soybean peptides achieve multi-dimensional quality stabilization in IFNP by targeted dual inhibition of lipid and protein oxidation pathways,thereby providing a solid theoretical foundation for their innovative application.展开更多
The changes and gastric digestive properties of gel were investigated for oxidiz ed myofibrillar protein(MP)(0–1 mmol/L H_(2)O_(2))treated by 30%substitution of NaCl with KCl,MgCl_(2),and KCl/MgCl_(2).Mild oxidation ...The changes and gastric digestive properties of gel were investigated for oxidiz ed myofibrillar protein(MP)(0–1 mmol/L H_(2)O_(2))treated by 30%substitution of NaCl with KCl,MgCl_(2),and KCl/MgCl_(2).Mild oxidation level(0.3 mmol/L H_(2)O_(2))facilitated the protein unfolding,and MgCl_(2)obviously intervened the protein selfassembly by forming the salt bridge and more disulfide bonds.At the same oxidation concentration,the sodium-reduced MP substituted with KCl formed dense network structure with better gel strength(increased by 6%–18%)and water retention in comparision to the gel without sodium reduction.The KCl-substituted gel chewing work was also relatively higher among the low-sodium samples at the first chewing cycle.Reversely,the relatively soft structure and lower gel viscosity in simulated oral chewing were found in MgCl_(2)-substituted gel.These changes decreased the contact limit between pepsin and protein for better gastric disintegration or pepsin diffusivity,and increased the proportion of small molecular weight peptides(25.83%,<5 kDa).Therefore,partial substitution of NaCl with other salt replacers could influence the physicochemical properties of low-sodium MP suspension or gel under different oxidation degree and the subsequent gastric digestion characteristics.展开更多
Many aquatic products have been stored using superchilling technology, but rarely used for the storage of sturgeon fillets. In this study, we investigated the effects of protein oxidation, cathepsin, and various freez...Many aquatic products have been stored using superchilling technology, but rarely used for the storage of sturgeon fillets. In this study, we investigated the effects of protein oxidation, cathepsin, and various freezing temperatures on the quality of superchilled sturgeon fillets. Sensory evaluation results showed that the sensory attributes of superchilled (−3 °C) sturgeon fillets were acceptable three times longer (18 days) than samples stored at refrigeration temperatures (4 °C). The sarcoplasmic protein, carbonyl, myofibrillar protein, total sulfhydryl content and the surface hydrophobicity were determined using fluorescence spectrophotometry and SDS-PAGE. Results showed that superchilling might protect myofibrillar proteins from oxidation compared to refrigeration temperatures. The activity of the three cathepsins (B, L, and H) in terms of myofibrillar, mitochondria, lysosomes, and sarcoplasm demonstrated that superchilling can inhibit cathepsins activity in sturgeon and protect its muscle structure. Microscopic observations showed that as the temperature decreased, the gap area of the muscle fibers decreased, and the deformation of cross-sectional slices was gradually reduced. In addition, the freezing rate of ice crystals produced during the freezing process influenced the muscle structure, texture, and sensory attributes. Superchilled sturgeon fillets showed good hardness, chewiness, and water retention. In conclusion, superchilling technology shows promise for its ability to extend the shelf life while maintaining the texture and sensory attributes of fresh sturgeon fillets.展开更多
Proteins are essential biomolecules that play a vital role in a wide range of biological processes.However,they can be affected by oxidative reactions,which can lead to protein oxidation,compromising their structural ...Proteins are essential biomolecules that play a vital role in a wide range of biological processes.However,they can be affected by oxidative reactions,which can lead to protein oxidation,compromising their structural integrity and nutritional and functional properties.Therefore,it is necessary to explore innovative preservation technologies to mitigate protein oxidation and prolong the shelf life of protein-based products.Currently,pressure-based preservation technologies such as high pressure processing(HPP),ultra high pressure homogenization(UHPH)and high pressure microfluidization(HPM)have been extensively studied to extend the shelf life of foods.These techniques have demonstrated their ability to inactivate microorganisms and enzymes,thereby preserving food and biological materials.However,they can cause a loss of quality in the food matrix,particularly through protein oxidation.Several studies have investigated the effect of HPP,UHPH and HPM on protein oxidation in various systems,including model proteins,meat,seafood,dairy and related products.The results indicate that protein oxidation is caused by free radicals,which may originate from a lipid or protein molecule in foods processed by these techniques.Once a free radical is formed,it initiates the oxidation of other proteins and lipids present in the system.Although significant progress has been made in comprehending the impact of these techniques on protein oxidation,there are still some knowledge gaps that need to be addressed.Therefore,this review paper aims to provide a summary of the current understanding of the impact of HPP,UHPH and HPM on protein oxidation.展开更多
BACKGROUND Esophageal cancer(ESCA)is among the most prevalent and lethal tumors globally.While nitric oxide synthase 1(NOS1)is recognized for its important in-volvement in various cancers,its specific function in ESCA...BACKGROUND Esophageal cancer(ESCA)is among the most prevalent and lethal tumors globally.While nitric oxide synthase 1(NOS1)is recognized for its important in-volvement in various cancers,its specific function in ESCA remains unclear.AIM To explore the potential role and underlying mechanisms of NOS1 in ESCA.METHODS Survival rates were analyzed using GeneCards and Gene Expression Profiling Interactive Analysis.The effects and mechanisms of NOS1 on ESCA cells were evaluated via the Cell Counting Kit-8 assay,scratch assay,Transwell assay,flow cytometry,quantitative polymerase chain reaction,western blotting,and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling staining.The protein interaction network was used to screen the interacting proteins of NOS1 and validate these interactions through co-immuno-precipitation and dual luciferase assays.Additionally,a nude mouse xenograft model was established to evaluate the effect of NOS1 in vivo.RESULTS The survival rate of patients with ESCA with high NOS1 expression was higher than that of patients with low NOS1 expression.NOS1 expression in ESCA cell lines was lower than that in normal esophageal epithelial cells.Overexpression of NOS1(oe-NOS1)inhibited proliferation,invasion,and migration abilities in ESCA cell lines,resulting in decreased autophagy levels and increased apoptosis,pyroptosis,and ferroptosis.Protein interaction studies confirmed the interaction between NOS1 and NOS1 adaptor protein(NOS1AP).Following oe-NOS1 and the silencing of NOS1AP,levels of P62 and microtubule-associated protein 1 light chain 3 beta increased both in vitro and in vivo.Furthermore,the expression levels of E-cadherin,along with the activation of phosphatidylinositol 3-kinase(PI3K)and protein kinase B(AKT),were inhibited in ESCA cell lines.CONCLUSION NOS1 and NOS1 proteins interact to suppress autophagy,activate the PI3K/AKT pathway,and exert anti-cancer effects in ESCA.展开更多
Cu-catalyzed oxidation of 5-hexyl-1,3-dihydroimidazo-2-one (1) in the presence of propylamine, as surrogates for the oxidized His side chain and Lys side chain, was investigated. 5-Hexylidene-4-propylamino-1,5-dihydro...Cu-catalyzed oxidation of 5-hexyl-1,3-dihydroimidazo-2-one (1) in the presence of propylamine, as surrogates for the oxidized His side chain and Lys side chain, was investigated. 5-Hexylidene-4-propylamino-1,5-dihydroimidazol-2-one (2), a model His-Lys cross-link product, was isolated and structurally characterized by NMR and mass spectrometry.展开更多
Background： Improving the unsaturated fatty acid content of ruminant meat is essential due to the generally saturated nature of fatty acids in ruminant meat and the negative effects this can have on human health. Non...Background： Improving the unsaturated fatty acid content of ruminant meat is essential due to the generally saturated nature of fatty acids in ruminant meat and the negative effects this can have on human health. Nonetheless, enhancing the unsaturated fatty acid content of ruminant meat can have adverse effects on the shelf life and quality attributes of the meat. This study assessed the effects of dietary 80 % canola oil and 20 % palm oil blend（CPOB） on fatty acid composition, antioxidants, oxidative spoilage, cholesterol and physicochemical properties of semimembranosus（SM）muscle from goats. Twenty four Boer bucks were randomly assigned to diets containing on dry matter basis 0, 4 and8 % CPOB, fed for 100 d and slaughtered. The carcasses were subjected to a 7 d postmortem refrigerated storage. Al analyses were conducted on the SM muscle.Results： Diet had no effect（P 〉 0.05） on the concentration of free thiol and carbonyl and the band intensity of myosin heavy chain, actin and troponin T. The muscle glycogen, p H, water holding capacity, tenderness, glutathione peroxidase（GPX） activity, total carotenoid, δ-tocopherol, cholesterol and proximate composition did not differ（P 〉 0.05） between diets. The SM muscle from goats fed 4 and 8 % CPOB had lower（P 〈 0.05） concentration of C14：0 and C16：0 and higher（P 〈 0.05） concentration of C18：1 trans-11, C18：1ω-9, C18：3ω-3, C20：5ω-3 and C22：5ω-3 than the SM muscle from the control goats. Dietary CPOB increased（P 〈 0.05） the concentration of α and γ tocopherol and meat redness（a＊） on d1 and 4 postmortem. Regardless of diet, antioxidant vitamins, and shear force decreased（P 〈 0.05） while drip loss, lipid and protein oxidation increased（P 〈 0.05） as postmortem storage progressed.Conclusion： Results evince that dietary CPOB can be used as a management tool to enhance the beneficial fatty acids and antioxidant contents of chevon without deleterious effects on its physicochemical properties and shelf life.展开更多
The aim of this study was to investigate the effect of different storage temperatures(4℃,25℃ and 45℃,denoted as T-4,T-25 and T-45,respectively)on the physical stability and protein-lipid co-oxidation of whey protei...The aim of this study was to investigate the effect of different storage temperatures(4℃,25℃ and 45℃,denoted as T-4,T-25 and T-45,respectively)on the physical stability and protein-lipid co-oxidation of whey protein functional emulsions during the storage period at storage times of 1,2,3 and 6 months.At the 6th month of storage,samples stored at 45℃ were less physically stable than samples stored at 4℃,as evidenced by an increase in particle size(5.50%),a decrease in zeta potential(7.93%),and a decrease in adsorbed protein concentration(36.8%).The most severe protein-lipid co-oxidation was induced in whey protein functional emulsions under 45℃ temperature conditions with increasing storage time.Protein oxidation products(carbonyls,N′-formyl-L-kynurenine,and sulfhydryl groups)and lipid oxidation products(lipid hydroperoxides,thiobarbituric acid reactive substances)were at their highest levels,and significant molecular changes were observed in the molecules of adsorbed protein or unadsorbed proteins.As the storage temperature rises it exposes the active sites such as internal sulfhydryl and hydrophobic groups in the protein,promoting cross-linking and aggregation.Cluster and correlation analyses showed that protein-lipid co-oxidation of emulsions inevitably occurs during storage,but low-temperature storage can delay this process.This study is of guiding significance for the quality maintenance of functional nutritional emulsions and the selection of storage conditions.In addition,this study may provide clearer solutions to the problems of whey protein denaturation and formation of lipid oxides caused by protein-lipid co-oxidation in the food industry,as well as to the problem of increasing the shelf life of products by choosing the appropriate storage,packaging,and transportation temperatures.展开更多
The oxidative modification of myofibrillar proteins(MPs)has been identified as a crucial factor affecting meat quality during processing.We compared the effects of 4-hydroxy-2-nonenal(HNE)and lipoxygenase(LOX)-catalyz...The oxidative modification of myofibrillar proteins(MPs)has been identified as a crucial factor affecting meat quality during processing.We compared the effects of 4-hydroxy-2-nonenal(HNE)and lipoxygenase(LOX)-catalyzed linoleic acid(LA)oxidation products on the digestibility and gel properties in MPs from bighead carp.Both treatments resulted in decreased free amino acid content,reduced digestibility,and loss of amino acids in MPs.The HNE treatment enhanced gel strength by increasing hydrophobic interactions within the gel matrix.Conversely,the LOX-catalyzed LA oxidation enhanced disulfide bonds,leading to an agglomerated microstructure.Reduced myofibrillar protein(MP)solubility,primarily due to protein aggregation,was observed in the LA group but not in the HNE group.This distinction suggests that the impact on MP functionality is predominantly influenced by the protein aggregation induced by LOX-catalyzed LA oxidation rather than by HNE alone.展开更多
The traditional Chinese medicine（Tripterygium wilfordii Hook.f., TWH） has been clinically used to treat primary and secondary renal diseases and proteinuria for nearly 40 years. However, there is a rare literature a...The traditional Chinese medicine（Tripterygium wilfordii Hook.f., TWH） has been clinically used to treat primary and secondary renal diseases and proteinuria for nearly 40 years. However, there is a rare literature about the effect of triptolide（the main active ingredient of TWH） on the expression of oxidative carbonyl protein（OCP） in diabetic nephropathy（DN）. This study aimed to provide experimental evidence for triptolide treatment on DN through its effect on the expression of OCP, in order to investigate the effects of triptolide on the expression of OCP in rats with DN. Sixty SD rats were randomly divided into five groups： control group, high-dose triptolide（Th） group, low-dose triptolide（Tl） group, DN model group, and positive control（benazepril） group. The DN model was established using streptozotocin. Urinary protein excretion, fasting blood glucose（FBG）, superoxide dismutase（SOD） in renal homogenate, malondialdehyde（MDA） in renal homogenate and renal nitrotyrosine by immunohistochemistry, and the expression of OCP by oxyblotimmune blotting were detected. In the DN model group, rat urinary protein excretion and renal MDA were significantly increased, while renal SOD significantly decreased and nitrotyrosine expression was obviously upregulated in the kidney. After triptolide treatment, 24-h urinary protein excretion（61.96±19.00 vs. 18.32±4.78 mg/day, P〈0.001）, renal MDA（8.09±0.79 vs. 5.45±0.68 nmol/L, P〈0.001）, and nitrotyrosine expression were decreased. Furthermore, renal OCP significantly decreased, while renal SOD（82.50±19.10 vs. 124.00±20.52 U/L, P〈0.001） was elevated. This study revealed that triptolide can down-regulate the expression of OCP in the renal cortex of DN rats.展开更多
Treatment with metformin can lead to the recovery of pleiotropic biological activities after spinal cord injury.However,its effect on spinal cord injury in aged mice remains unclear.Considering the essential role of a...Treatment with metformin can lead to the recovery of pleiotropic biological activities after spinal cord injury.However,its effect on spinal cord injury in aged mice remains unclear.Considering the essential role of angiogenesis during the regeneration process,we hypothesized that metformin activates the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway in endothelial cells,thereby promoting microvascular regeneration in aged mice after spinal cord injury.In this study,we established young and aged mouse models of contusive spinal cord injury using a modified Allen method.We found that aging hindered the recovery of neurological function and the formation of blood vessels in the spinal cord.Treatment with metformin promoted spinal cord microvascular endothelial cell migration and blood vessel formation in vitro.Furthermore,intraperitoneal injection of metformin in an in vivo model promoted endothelial cell proliferation and increased the density of new blood vessels in the spinal cord,thereby improving neurological function.The role of metformin was reversed by compound C,an adenosine monophosphate-activated protein kinase inhibitor,both in vivo and in vitro,suggesting that the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway likely regulates metformin-mediated angiogenesis after spinal cord injury.These findings suggest that metformin promotes vascular regeneration in the injured spinal cord by activating the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway,thereby improving the neurological function of aged mice after spinal cord injury.展开更多
The aim was to investigate the molecular mechanisms responsible for the inducible nitric oxide synthase （iNOS） gene expression stimulated by lipid associated membrane proteins （LAMPs） of Ureaplasma urealytictan （...The aim was to investigate the molecular mechanisms responsible for the inducible nitric oxide synthase （iNOS） gene expression stimulated by lipid associated membrane proteins （LAMPs） of Ureaplasma urealytictan （ U. urealyticum ）. Detection of NO, the expression of iNOS and the activation of nuclear factor κB （NF-κB） in direct response to U. urealyticum LAMPs in a murine macrophages, the effects of pyrrolidine dithiocarbamate （PDTC）, an inhibitor of NF-κB and of cycloheximide （CHX）, a protein synthase inhibitor were available. The results indicated that U. urealyticum LAMPs stimulated mouse macrophages to express iNOS and thus produce NO in dose- and time-dependent manner by activating NF-κB. The expression of iNOS, NO production and the activation of NF-κB were inhibited by U. urealyticum LAMPs combination with PDTC or CHX. In conclusion, our findings suggest that U. urealyticum may be an etiological factor to certain diseases due to its ability to stimulate the expression of iNOS, which is probably mediated through the activation of NF-κB.展开更多
The sensory characteristics of chicken skin chewy and soft are a crucial demand of consumers for hedonism of Chinese style soft-boiled chicken(Bai Qie Ji).In this investigation,the surface hydrophobicity of chicken sk...The sensory characteristics of chicken skin chewy and soft are a crucial demand of consumers for hedonism of Chinese style soft-boiled chicken(Bai Qie Ji).In this investigation,the surface hydrophobicity of chicken skin protein was found to be the highest at 60 min.The exposure of hydrophobic groups led to the formation of protein cross-linking aggregates.The main force of maintaining protein was disulfide bond and hydrophobic interaction after stewing.A total of 536 metabolites with significant differences(P<0.05)were identified,among which amino acids,peptides and analogues,glycerophosphocholines,fatty acids and conjugates accounted for the majority.The t-g-t,β-sheet andβ-turn,N-acyl amino acid and 5’-umami nucleotide was significantly positively correlated with stewing time.In summary,the chicken skin collagen structure was conferred by augmented disulfide bonds,and N-acyl amino acids were pivotal metabolites,which offering novel insights into the processing mechanism of collagenous foodstuffs.展开更多
This study systematically investigated the effects of deep-frying temperatures(150℃,180℃,210℃)on protein structure reorganization and textural evolution in beef.Through integrating low-field nuclear magnetic resona...This study systematically investigated the effects of deep-frying temperatures(150℃,180℃,210℃)on protein structure reorganization and textural evolution in beef.Through integrating low-field nuclear magnetic resonance(LF-NMR),Fourier transform infrared spectroscopy(FTIR),and biochemical assays,we revealed that elevated temperatures induced hierarchical alterations.Biochemical assays demonstrated progressive increases in protein carbonyl content,lipid oxidation,and protein hydrophobicity,alongside reductions in sulfhydryl content and protein solubility,as temperature increased.LF-NMR analysis indicated a reduction in the proportions of bound and free water,with moisture redistribution into immobilized states at higher temperatures.FTIR analysis revealed temperature-dependent structural transitions:α-helix,β-turn,andβ-sheet contents decreased,while random coil content increased,correlating with diminished elasticity and cohesiveness.Additionally,higher temperatures induced surface hardening,limited sodium chloride diffusion and altered color parameters(reduced redness and increased yellowness).These findings underscore the trade-offs between thermal processing benefits and oxidative compromises,providing critical insights for optimizing traditional deep-frying conditions to balance sensory quality,nutritional retention,and consumer acceptability.展开更多
Objective To evaluate the oxidative stress in patients with colorectal cancer and to investigate the relationship between oxidative stress and colorectal cancer. Methods Seventy-six subjects were divided into two grou...Objective To evaluate the oxidative stress in patients with colorectal cancer and to investigate the relationship between oxidative stress and colorectal cancer. Methods Seventy-six subjects were divided into two groups （36 colorectal cancer patients as the study group and 40 normal healthy individuals as the control group）. Their protein oxidation, DNA damage, lipid peroxidation and antioxidants, vitamin C, vitamin E, glutathione （GSH）, and antioxidative enzymes in serum were detected. Results The levels of protein carbonyl and advanced oxidation protein products （AOPP） were significantly higher in the study group than in the control group （P〈0.01）. Serum 8-OHdG was significantly increased in the study group compared to the control group （P〈0.01）. However, the mean serum level of MDA and conjugated diene was lower in the study group than in the control group （P〈0.01）. The activity of antioxidative enzymes was significantly decreased in the study group compared to the control group （P〈0.01）. Serum vitamins C and E concentrations were significantly reduced in the study group compared to the control group （P〈0.01）. Conclusion Colorectal cancer is associated with oxidative stress, and assessment of oxidative stress and given antioxidants is important for the treatment and prevention of colorectal cancer.展开更多
The effect of the addition of natural antioxidants from strawberry tree （Arbutus unedo L.; AU） and dog rose （Rosa canina L.; RC）, in frankfurters elaborated with or without the addition of antioxidant additives （...The effect of the addition of natural antioxidants from strawberry tree （Arbutus unedo L.; AU） and dog rose （Rosa canina L.; RC）, in frankfurters elaborated with or without the addition of antioxidant additives （sodium ascorbate and nitrite） was studied. Six different types of experimental frankfurters were prepared depending on the addition of phenolic-rich extracts from RC and AU and the presence （P） or absence （C） of antioxidant additives. Thiobarbituric acid reactive substances （TBARS）-numbers signiifcantly increased during chilled storage of C-frankfurters while additives and fruit phenolics inhibited lipid oxidation in P-frankfurters. The amount of protein carbonyls signiifcantly increased in all treatments except in P-AU frankfurters. The discoloration process that occurred during the chilled storage was reduced by the addition of substances with proven antioxidant activity （P-frankfurters）. Texture characteristics as hardness, springiness, cohesiveness and gumminess also suffered a signiifcant deterioration in C-frankfurters. The use of phenolic fruit extracts in combination with traditional antioxidant additives is a successful strategy to enhance the oxidative stability of frankfurters without modifying their color and texture properties.展开更多
基金This study was financially supported by National Key R&D Program of China(grant No.2017YFD0400105)Natural Science Foundation of Beijing Municipality(grant No.6192009)Fengtai science and technology new star(grant No.KJXX201902).
文摘The effect of sodium chloride(NaCl)curing salt content on protein oxidation,lipid oxidation and lipolysis of Chinese dry sausage was investigated.Two groups Chinese dry sausages with 2%and 4%(m/m)salt content were studied.The degree of protein oxidation increased during the processes in two groups sausages,while the content of phospholipids decreased,neutral lipids and free fatty acids increased.The degree of protein oxidation,lipid oxidation and lipolysis in 4%NaCl content group was higher than those in 2%NaCl content group,while 4%NaCl content group has higher lipase activity.In conclusion,4%NaCl may facilitate the protein oxidation,lipid hydrolysis and oxidation in Chinese dry sausage,and the protein oxidation had strong correlation with lipid oxidation and lipolysis.The results could provide a basis for improving the technology of industrial production.
基金supported by National Key R&D Program of China(2021YFD2100104)griculture Research System of China(CARS-41-Z)+2 种基金Science and Technology Project of Nanjing City(202002040)Jiangsu Province Policy Guidance Program(BX2020008)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX21_0579),China。
文摘Investigation that protein oxidation to the formation of advanced glycation end products(AGEs)after chicken myofibrillar protein glycation is limited.Models of protein oxidation induced by different concentrations of hydroxyl radicals(·OH)were developed after the chicken myofibrillar protein mild glycation(MPG).Results exhibited that levels of AGEs and surface hydrophobicity(H_(0))steadily increased with the a ddition of h ydrogen peroxide(H_(2)O_(2))concentration.However,levels of s ulfhydryl group,free amino group,and particle size gradually decreased with the H_(2)O_(2)concentration.The protein carbonyl value increased in H_(2)O_(2)concentration until 10 mmol/L.Pearson's correlation indicated that MPG structure modification(unfolding and degradation)induced by protein oxidation were significantly positively correlated with AGEs concentration(P<0.05).Finally,a mechanism was proposed to hypothesize t he effect of protein oxidation on the formation of AGEs under MPG conditions.
文摘Introduction: The kinetics of protein oxidation, monitored in breath, and its contribution to the whole body protein status is not well established. Objectives: To analyze protein oxidation in various metabolic conditions we developed/validated a <sup>13</sup>C-protein oxidation breath test using low enriched milk proteins. Method/Design: 30 g of naturally labeled <sup>13</sup>C-milk proteins were consumed by young healthy volunteers. Breath samples were taken every 10 min and <sup>13</sup>CO<sub>2</sub> was measured by Isotope Ratio Mass Spectrometry. To calculate the amount of oxidized substrate we used: substrate dose, molecular weight and <sup>13</sup>C enrichment of the substrate, number of carbon atoms in a substrate molecule, and estimated CO<sub>2</sub>-production of the subject based on body surface area. Results: We demonstrated that in 255 min 20% ± 3% (mean ± SD) of the milk protein was oxidized compared to 18% ± 1% of 30 g glucose. Postprandial kinetics of oxidation of whey (rapidly digestible protein) and casein (slowly digestible protein) derived from our breath test were comparable to literature data regarding the kinetics of appearance of amino acids in blood. Oxidation of milk proteins was faster than that of milk lipids (peak oxidation 120 and 290 minutes, respectively). After a 3-day protein restricted diet (~10 g of protein/day) a decrease of 31% ± 18% in milk protein oxidation was observed compared to a normal diet. Conclusions: Protein oxidation, which can be easily monitored in breath, is a significant factor in protein metabolism. With our technique we are able to characterize changes in overall protein oxidation under various meta-bolic conditions such as a protein restricted diet, which could be relevant for defining optimal protein intake under various conditions. Measuring protein oxidation in new-born might be relevant to establish its contribution to the protein status and its age-dependent development.
基金supported by the earmarked fund for China Agriculture Research System of MOF and MARA(CARS-35)Doctoral Research Initiation Fee Grant Program,Guangdong Ocean University(060302042315)。
文摘This study investigated the protective effect of ferulic acid(FA) on the digestibility of oxidized beef myofibrillar protein(MP).MP were treated with varying concentrations of FA(20,40,and 80 μmol/g pro) and then exposed to oxidation.The results showed that FA inhibited carbonyl in a dose-dependent manner.Fluorescence spectroscopy and molecular docking studies revealed FA was bonded to MP via hydrophobic interactions and hydrogen bonds.Sodium dodecyl sulfate polyacrylamide gel electrophoresis and transmission electron microscope analysis indicated that FA mitigated the aggregation of oxidized MP.Peptidomic analysis showed FA protected 34.24% peptides recover from oxidation loss,and theses recovered peptide were mainly distributed in hydrophobic regions and lysine sites.In vitro digestion showed FA remarkably improved digestibility of oxidized MP(P < 0.05),with 80 μmol/g pro FA mitigating 67.85% loss in digestibility.Overall,FA effectively preserved the release of peptides by inhibiting hydrophobic aggregation and oxidation of lysine residues,thereby alleviating the decrease in digestibility of oxidized MP.
基金the financial support provided by the Major Scientific and Technological Research and Development Projects of Jiangxi province(20203ABC28W015).
文摘This study systematically investigated the mechanism by which soybean peptides regulate the flavor and quality stability of infant formula nutrition powder(IFNP)during 300-day storage.The results demonstrated that soy-bean peptide supplementation significantly improved product quality by increasing vitamin A and D retention rates by 6.24%and 15.94%respectively,enhancing dispersibility by 23.08%,and effectively mitigating color deterioration.A flavor fingerprint profile was constructed based on Gas Chromatography-Ion Mobility Spectrometry(GC-IMS)technology,and a total of 49 volatile flavor substances were identified.9 key off-flavor substances were screened out by subsequent multivariate statistical analysis.Soybean peptides significantly inhibited their accumulation,with inhibition rates reaching 46.61% for(E)-2-hexenal and 43.37% for 1-hexanal,while promoting the retention of beneficial flavor components including esters and alcohols,thereby substantially enhancing flavor stability.At the molecular level,soybean peptides exhibited remarkable antioxidant activity,reducing total free radical intensity by 6.06% through effective radical scavenging,interrupting lipid oxidation chain reactions,decreasing malondialdehyde content,and preserving unsaturated fatty acid structures.Concurrently,they significantly suppressed protein oxidative damage,as evidenced by reduced carbonyl content and maintained free sulfhydryl groups.Multivariate correlation analysis further constructed a complete quality deterioration network,confirming the synergistic relationship between lipid and protein oxidation in driving overall quality degradation.This research clarified that soybean peptides achieve multi-dimensional quality stabilization in IFNP by targeted dual inhibition of lipid and protein oxidation pathways,thereby providing a solid theoretical foundation for their innovative application.
基金supported by the National Natural Science Foundation of China(32172257)the Ministry of Science and Technology of the People’s Republic of China(DL2022163005L)+2 种基金the Science and Technology Program of Qingyuan(2022KJJH018)the Postdoctoral Innovative Talent Support Program(BX20230130)the 111 Project(B17018).
文摘The changes and gastric digestive properties of gel were investigated for oxidiz ed myofibrillar protein(MP)(0–1 mmol/L H_(2)O_(2))treated by 30%substitution of NaCl with KCl,MgCl_(2),and KCl/MgCl_(2).Mild oxidation level(0.3 mmol/L H_(2)O_(2))facilitated the protein unfolding,and MgCl_(2)obviously intervened the protein selfassembly by forming the salt bridge and more disulfide bonds.At the same oxidation concentration,the sodium-reduced MP substituted with KCl formed dense network structure with better gel strength(increased by 6%–18%)and water retention in comparision to the gel without sodium reduction.The KCl-substituted gel chewing work was also relatively higher among the low-sodium samples at the first chewing cycle.Reversely,the relatively soft structure and lower gel viscosity in simulated oral chewing were found in MgCl_(2)-substituted gel.These changes decreased the contact limit between pepsin and protein for better gastric disintegration or pepsin diffusivity,and increased the proportion of small molecular weight peptides(25.83%,<5 kDa).Therefore,partial substitution of NaCl with other salt replacers could influence the physicochemical properties of low-sodium MP suspension or gel under different oxidation degree and the subsequent gastric digestion characteristics.
基金financial support from the Key Laboratory of Aquatic Product Processing,Ministry of Agriculture,P.R.China(NYJG201901)Natural Science Foundation of Shandong Province(ZR2019MC014)+1 种基金China Agriculture Research System of MOF and MARA(CARS-46)Jiangsu Provincial Science and Technology Program(LYG-SZ201815).
文摘Many aquatic products have been stored using superchilling technology, but rarely used for the storage of sturgeon fillets. In this study, we investigated the effects of protein oxidation, cathepsin, and various freezing temperatures on the quality of superchilled sturgeon fillets. Sensory evaluation results showed that the sensory attributes of superchilled (−3 °C) sturgeon fillets were acceptable three times longer (18 days) than samples stored at refrigeration temperatures (4 °C). The sarcoplasmic protein, carbonyl, myofibrillar protein, total sulfhydryl content and the surface hydrophobicity were determined using fluorescence spectrophotometry and SDS-PAGE. Results showed that superchilling might protect myofibrillar proteins from oxidation compared to refrigeration temperatures. The activity of the three cathepsins (B, L, and H) in terms of myofibrillar, mitochondria, lysosomes, and sarcoplasm demonstrated that superchilling can inhibit cathepsins activity in sturgeon and protect its muscle structure. Microscopic observations showed that as the temperature decreased, the gap area of the muscle fibers decreased, and the deformation of cross-sectional slices was gradually reduced. In addition, the freezing rate of ice crystals produced during the freezing process influenced the muscle structure, texture, and sensory attributes. Superchilled sturgeon fillets showed good hardness, chewiness, and water retention. In conclusion, superchilling technology shows promise for its ability to extend the shelf life while maintaining the texture and sensory attributes of fresh sturgeon fillets.
基金support from PT national funds(FCT/MCTES,Fundação para a Ciência e Tecnologia and Ministério da Ciência,Tecnologia e Ensino Superior)through the projects 10.54499/LA/P/0008/2020,10.54499/UIDP/50006/2020,and 10.54499/UIDB/50006/2020the FCT/MCTES for the PhD fellowships of Alireza Mousakhani Ganjeh(2022.12558.BD)Carlos A.Pinto(SFRH/BD/137036/2018 and COVID/BD/153220/2023).
文摘Proteins are essential biomolecules that play a vital role in a wide range of biological processes.However,they can be affected by oxidative reactions,which can lead to protein oxidation,compromising their structural integrity and nutritional and functional properties.Therefore,it is necessary to explore innovative preservation technologies to mitigate protein oxidation and prolong the shelf life of protein-based products.Currently,pressure-based preservation technologies such as high pressure processing(HPP),ultra high pressure homogenization(UHPH)and high pressure microfluidization(HPM)have been extensively studied to extend the shelf life of foods.These techniques have demonstrated their ability to inactivate microorganisms and enzymes,thereby preserving food and biological materials.However,they can cause a loss of quality in the food matrix,particularly through protein oxidation.Several studies have investigated the effect of HPP,UHPH and HPM on protein oxidation in various systems,including model proteins,meat,seafood,dairy and related products.The results indicate that protein oxidation is caused by free radicals,which may originate from a lipid or protein molecule in foods processed by these techniques.Once a free radical is formed,it initiates the oxidation of other proteins and lipids present in the system.Although significant progress has been made in comprehending the impact of these techniques on protein oxidation,there are still some knowledge gaps that need to be addressed.Therefore,this review paper aims to provide a summary of the current understanding of the impact of HPP,UHPH and HPM on protein oxidation.
基金Supported by the National Natural Science Foundation of China,No.81000201.
文摘BACKGROUND Esophageal cancer(ESCA)is among the most prevalent and lethal tumors globally.While nitric oxide synthase 1(NOS1)is recognized for its important in-volvement in various cancers,its specific function in ESCA remains unclear.AIM To explore the potential role and underlying mechanisms of NOS1 in ESCA.METHODS Survival rates were analyzed using GeneCards and Gene Expression Profiling Interactive Analysis.The effects and mechanisms of NOS1 on ESCA cells were evaluated via the Cell Counting Kit-8 assay,scratch assay,Transwell assay,flow cytometry,quantitative polymerase chain reaction,western blotting,and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling staining.The protein interaction network was used to screen the interacting proteins of NOS1 and validate these interactions through co-immuno-precipitation and dual luciferase assays.Additionally,a nude mouse xenograft model was established to evaluate the effect of NOS1 in vivo.RESULTS The survival rate of patients with ESCA with high NOS1 expression was higher than that of patients with low NOS1 expression.NOS1 expression in ESCA cell lines was lower than that in normal esophageal epithelial cells.Overexpression of NOS1(oe-NOS1)inhibited proliferation,invasion,and migration abilities in ESCA cell lines,resulting in decreased autophagy levels and increased apoptosis,pyroptosis,and ferroptosis.Protein interaction studies confirmed the interaction between NOS1 and NOS1 adaptor protein(NOS1AP).Following oe-NOS1 and the silencing of NOS1AP,levels of P62 and microtubule-associated protein 1 light chain 3 beta increased both in vitro and in vivo.Furthermore,the expression levels of E-cadherin,along with the activation of phosphatidylinositol 3-kinase(PI3K)and protein kinase B(AKT),were inhibited in ESCA cell lines.CONCLUSION NOS1 and NOS1 proteins interact to suppress autophagy,activate the PI3K/AKT pathway,and exert anti-cancer effects in ESCA.
文摘Cu-catalyzed oxidation of 5-hexyl-1,3-dihydroimidazo-2-one (1) in the presence of propylamine, as surrogates for the oxidized His side chain and Lys side chain, was investigated. 5-Hexylidene-4-propylamino-1,5-dihydroimidazol-2-one (2), a model His-Lys cross-link product, was isolated and structurally characterized by NMR and mass spectrometry.
文摘Background： Improving the unsaturated fatty acid content of ruminant meat is essential due to the generally saturated nature of fatty acids in ruminant meat and the negative effects this can have on human health. Nonetheless, enhancing the unsaturated fatty acid content of ruminant meat can have adverse effects on the shelf life and quality attributes of the meat. This study assessed the effects of dietary 80 % canola oil and 20 % palm oil blend（CPOB） on fatty acid composition, antioxidants, oxidative spoilage, cholesterol and physicochemical properties of semimembranosus（SM）muscle from goats. Twenty four Boer bucks were randomly assigned to diets containing on dry matter basis 0, 4 and8 % CPOB, fed for 100 d and slaughtered. The carcasses were subjected to a 7 d postmortem refrigerated storage. Al analyses were conducted on the SM muscle.Results： Diet had no effect（P 〉 0.05） on the concentration of free thiol and carbonyl and the band intensity of myosin heavy chain, actin and troponin T. The muscle glycogen, p H, water holding capacity, tenderness, glutathione peroxidase（GPX） activity, total carotenoid, δ-tocopherol, cholesterol and proximate composition did not differ（P 〉 0.05） between diets. The SM muscle from goats fed 4 and 8 % CPOB had lower（P 〈 0.05） concentration of C14：0 and C16：0 and higher（P 〈 0.05） concentration of C18：1 trans-11, C18：1ω-9, C18：3ω-3, C20：5ω-3 and C22：5ω-3 than the SM muscle from the control goats. Dietary CPOB increased（P 〈 0.05） the concentration of α and γ tocopherol and meat redness（a＊） on d1 and 4 postmortem. Regardless of diet, antioxidant vitamins, and shear force decreased（P 〈 0.05） while drip loss, lipid and protein oxidation increased（P 〈 0.05） as postmortem storage progressed.Conclusion： Results evince that dietary CPOB can be used as a management tool to enhance the beneficial fatty acids and antioxidant contents of chevon without deleterious effects on its physicochemical properties and shelf life.
基金financially supported by the National Key Research and Development Program of China(2022YFF1100402)the National Natural Science Foundation of China(No.31801518 and 31601450)the China Postdoctoral Science Foundation(2024T170256).
文摘The aim of this study was to investigate the effect of different storage temperatures(4℃,25℃ and 45℃,denoted as T-4,T-25 and T-45,respectively)on the physical stability and protein-lipid co-oxidation of whey protein functional emulsions during the storage period at storage times of 1,2,3 and 6 months.At the 6th month of storage,samples stored at 45℃ were less physically stable than samples stored at 4℃,as evidenced by an increase in particle size(5.50%),a decrease in zeta potential(7.93%),and a decrease in adsorbed protein concentration(36.8%).The most severe protein-lipid co-oxidation was induced in whey protein functional emulsions under 45℃ temperature conditions with increasing storage time.Protein oxidation products(carbonyls,N′-formyl-L-kynurenine,and sulfhydryl groups)and lipid oxidation products(lipid hydroperoxides,thiobarbituric acid reactive substances)were at their highest levels,and significant molecular changes were observed in the molecules of adsorbed protein or unadsorbed proteins.As the storage temperature rises it exposes the active sites such as internal sulfhydryl and hydrophobic groups in the protein,promoting cross-linking and aggregation.Cluster and correlation analyses showed that protein-lipid co-oxidation of emulsions inevitably occurs during storage,but low-temperature storage can delay this process.This study is of guiding significance for the quality maintenance of functional nutritional emulsions and the selection of storage conditions.In addition,this study may provide clearer solutions to the problems of whey protein denaturation and formation of lipid oxides caused by protein-lipid co-oxidation in the food industry,as well as to the problem of increasing the shelf life of products by choosing the appropriate storage,packaging,and transportation temperatures.
基金supported by the National Key R&D Program of China(2022YFD2100902)the National Natural Science Foundation of China(32172133)+1 种基金the earmarked fund forCARS(CARS-45)funded by Chiang Mai University.
文摘The oxidative modification of myofibrillar proteins(MPs)has been identified as a crucial factor affecting meat quality during processing.We compared the effects of 4-hydroxy-2-nonenal(HNE)and lipoxygenase(LOX)-catalyzed linoleic acid(LA)oxidation products on the digestibility and gel properties in MPs from bighead carp.Both treatments resulted in decreased free amino acid content,reduced digestibility,and loss of amino acids in MPs.The HNE treatment enhanced gel strength by increasing hydrophobic interactions within the gel matrix.Conversely,the LOX-catalyzed LA oxidation enhanced disulfide bonds,leading to an agglomerated microstructure.Reduced myofibrillar protein(MP)solubility,primarily due to protein aggregation,was observed in the LA group but not in the HNE group.This distinction suggests that the impact on MP functionality is predominantly influenced by the protein aggregation induced by LOX-catalyzed LA oxidation rather than by HNE alone.
基金supported by the program for Outstanding Academic Leaders Training Plan of Health System of Huangpu District of Shanghai from 2013 to 2016 year(No.2013-18)
文摘The traditional Chinese medicine（Tripterygium wilfordii Hook.f., TWH） has been clinically used to treat primary and secondary renal diseases and proteinuria for nearly 40 years. However, there is a rare literature about the effect of triptolide（the main active ingredient of TWH） on the expression of oxidative carbonyl protein（OCP） in diabetic nephropathy（DN）. This study aimed to provide experimental evidence for triptolide treatment on DN through its effect on the expression of OCP, in order to investigate the effects of triptolide on the expression of OCP in rats with DN. Sixty SD rats were randomly divided into five groups： control group, high-dose triptolide（Th） group, low-dose triptolide（Tl） group, DN model group, and positive control（benazepril） group. The DN model was established using streptozotocin. Urinary protein excretion, fasting blood glucose（FBG）, superoxide dismutase（SOD） in renal homogenate, malondialdehyde（MDA） in renal homogenate and renal nitrotyrosine by immunohistochemistry, and the expression of OCP by oxyblotimmune blotting were detected. In the DN model group, rat urinary protein excretion and renal MDA were significantly increased, while renal SOD significantly decreased and nitrotyrosine expression was obviously upregulated in the kidney. After triptolide treatment, 24-h urinary protein excretion（61.96±19.00 vs. 18.32±4.78 mg/day, P〈0.001）, renal MDA（8.09±0.79 vs. 5.45±0.68 nmol/L, P〈0.001）, and nitrotyrosine expression were decreased. Furthermore, renal OCP significantly decreased, while renal SOD（82.50±19.10 vs. 124.00±20.52 U/L, P〈0.001） was elevated. This study revealed that triptolide can down-regulate the expression of OCP in the renal cortex of DN rats.
基金supported by the Natural Nature Science Foundation of China,Nos.82030071,81874004the Science and Technology Major Project of Changsha,No.kh2103008(all to JZH).
文摘Treatment with metformin can lead to the recovery of pleiotropic biological activities after spinal cord injury.However,its effect on spinal cord injury in aged mice remains unclear.Considering the essential role of angiogenesis during the regeneration process,we hypothesized that metformin activates the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway in endothelial cells,thereby promoting microvascular regeneration in aged mice after spinal cord injury.In this study,we established young and aged mouse models of contusive spinal cord injury using a modified Allen method.We found that aging hindered the recovery of neurological function and the formation of blood vessels in the spinal cord.Treatment with metformin promoted spinal cord microvascular endothelial cell migration and blood vessel formation in vitro.Furthermore,intraperitoneal injection of metformin in an in vivo model promoted endothelial cell proliferation and increased the density of new blood vessels in the spinal cord,thereby improving neurological function.The role of metformin was reversed by compound C,an adenosine monophosphate-activated protein kinase inhibitor,both in vivo and in vitro,suggesting that the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway likely regulates metformin-mediated angiogenesis after spinal cord injury.These findings suggest that metformin promotes vascular regeneration in the injured spinal cord by activating the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway,thereby improving the neurological function of aged mice after spinal cord injury.
文摘The aim was to investigate the molecular mechanisms responsible for the inducible nitric oxide synthase （iNOS） gene expression stimulated by lipid associated membrane proteins （LAMPs） of Ureaplasma urealytictan （ U. urealyticum ）. Detection of NO, the expression of iNOS and the activation of nuclear factor κB （NF-κB） in direct response to U. urealyticum LAMPs in a murine macrophages, the effects of pyrrolidine dithiocarbamate （PDTC）, an inhibitor of NF-κB and of cycloheximide （CHX）, a protein synthase inhibitor were available. The results indicated that U. urealyticum LAMPs stimulated mouse macrophages to express iNOS and thus produce NO in dose- and time-dependent manner by activating NF-κB. The expression of iNOS, NO production and the activation of NF-κB were inhibited by U. urealyticum LAMPs combination with PDTC or CHX. In conclusion, our findings suggest that U. urealyticum may be an etiological factor to certain diseases due to its ability to stimulate the expression of iNOS, which is probably mediated through the activation of NF-κB.
基金supported by China Agriculture Research System of MOF and MARA(CARS-41)National Natural Science Foundation of China(No.32472259).
文摘The sensory characteristics of chicken skin chewy and soft are a crucial demand of consumers for hedonism of Chinese style soft-boiled chicken(Bai Qie Ji).In this investigation,the surface hydrophobicity of chicken skin protein was found to be the highest at 60 min.The exposure of hydrophobic groups led to the formation of protein cross-linking aggregates.The main force of maintaining protein was disulfide bond and hydrophobic interaction after stewing.A total of 536 metabolites with significant differences(P<0.05)were identified,among which amino acids,peptides and analogues,glycerophosphocholines,fatty acids and conjugates accounted for the majority.The t-g-t,β-sheet andβ-turn,N-acyl amino acid and 5’-umami nucleotide was significantly positively correlated with stewing time.In summary,the chicken skin collagen structure was conferred by augmented disulfide bonds,and N-acyl amino acids were pivotal metabolites,which offering novel insights into the processing mechanism of collagenous foodstuffs.
基金funded by Cuisine Science Key Laboratory of Sichuan Province,Sichuan Tourism University,grant number PRKX2024Z05Sichuan University of Science and Engineering,grant number Y2024228.
文摘This study systematically investigated the effects of deep-frying temperatures(150℃,180℃,210℃)on protein structure reorganization and textural evolution in beef.Through integrating low-field nuclear magnetic resonance(LF-NMR),Fourier transform infrared spectroscopy(FTIR),and biochemical assays,we revealed that elevated temperatures induced hierarchical alterations.Biochemical assays demonstrated progressive increases in protein carbonyl content,lipid oxidation,and protein hydrophobicity,alongside reductions in sulfhydryl content and protein solubility,as temperature increased.LF-NMR analysis indicated a reduction in the proportions of bound and free water,with moisture redistribution into immobilized states at higher temperatures.FTIR analysis revealed temperature-dependent structural transitions:α-helix,β-turn,andβ-sheet contents decreased,while random coil content increased,correlating with diminished elasticity and cohesiveness.Additionally,higher temperatures induced surface hardening,limited sodium chloride diffusion and altered color parameters(reduced redness and increased yellowness).These findings underscore the trade-offs between thermal processing benefits and oxidative compromises,providing critical insights for optimizing traditional deep-frying conditions to balance sensory quality,nutritional retention,and consumer acceptability.
基金the grant from the Health Bureau of Heilongjiang Province (No. 2005-126)the Natural Science Foundation of Heilongjiang Province (No. D2007-29)
文摘Objective To evaluate the oxidative stress in patients with colorectal cancer and to investigate the relationship between oxidative stress and colorectal cancer. Methods Seventy-six subjects were divided into two groups （36 colorectal cancer patients as the study group and 40 normal healthy individuals as the control group）. Their protein oxidation, DNA damage, lipid peroxidation and antioxidants, vitamin C, vitamin E, glutathione （GSH）, and antioxidative enzymes in serum were detected. Results The levels of protein carbonyl and advanced oxidation protein products （AOPP） were significantly higher in the study group than in the control group （P〈0.01）. Serum 8-OHdG was significantly increased in the study group compared to the control group （P〈0.01）. However, the mean serum level of MDA and conjugated diene was lower in the study group than in the control group （P〈0.01）. The activity of antioxidative enzymes was significantly decreased in the study group compared to the control group （P〈0.01）. Serum vitamins C and E concentrations were significantly reduced in the study group compared to the control group （P〈0.01）. Conclusion Colorectal cancer is associated with oxidative stress, and assessment of oxidative stress and given antioxidants is important for the treatment and prevention of colorectal cancer.
基金supported by the Spanish CDTI Program(IDI 20090264)the Spanish Ministry of Science and Innovation for the contract through the Ramón y Cajal(RYC-2009-03901) program+3 种基金the support through the project Protein Oxidation in Frozen Meat and Dry-Cured Products:MechanismsConsequences and Development of Antioxidant Strategies(AGL2010-15134)The European Community (Research Executive Agency) is also acknowledged for the Marie Curie Reintegration Fellowship(PERG05-GA-2009-248959 Pox-MEAT)
文摘The effect of the addition of natural antioxidants from strawberry tree （Arbutus unedo L.; AU） and dog rose （Rosa canina L.; RC）, in frankfurters elaborated with or without the addition of antioxidant additives （sodium ascorbate and nitrite） was studied. Six different types of experimental frankfurters were prepared depending on the addition of phenolic-rich extracts from RC and AU and the presence （P） or absence （C） of antioxidant additives. Thiobarbituric acid reactive substances （TBARS）-numbers signiifcantly increased during chilled storage of C-frankfurters while additives and fruit phenolics inhibited lipid oxidation in P-frankfurters. The amount of protein carbonyls signiifcantly increased in all treatments except in P-AU frankfurters. The discoloration process that occurred during the chilled storage was reduced by the addition of substances with proven antioxidant activity （P-frankfurters）. Texture characteristics as hardness, springiness, cohesiveness and gumminess also suffered a signiifcant deterioration in C-frankfurters. The use of phenolic fruit extracts in combination with traditional antioxidant additives is a successful strategy to enhance the oxidative stability of frankfurters without modifying their color and texture properties.
