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1.
Previously, we have found phosphopeptides (PPPs) from hen egg yolk phosvitin possess a potent antioxidative activity against oxidative stress in human intestinal epithelial cells, Caco-2. However, their biological activity at the cellular level has not yet fully understood. The objective of this study is to evaluate the regulation of glutathione (GSH) biosynthesis-associated and antioxidant enzymes against oxidative stress in Caco-2 cells using an in vitro model. Treatment of 1 mM H2O2-induced Caco-2 cells with PPPs increased cellular GSH levels, concomitant with a significant increase in gamma-glutamylcysteine synthetase (gamma-GCS) activity and the expression of gamma-GCS heavy subunit mRNA. Furthermore, intracellular glutathione reductase, glutathione S-transferase, and catalase activities were elevated by PPPs. In addition, PPPs with high content of phosphorus showed higher induction of these enzyme activities than PPPs without phosphorus. These data indicate that oligophosphopeptides from hen egg yolk phosvitin can up-regulate cellular GSH biosynthesis-associated enzymes activity and antioxidative activities, which play key roles against tissue oxidative stress in the human intestinal epithelial cells.  相似文献   

2.
The protective effects of hen egg yolk phosvitin phosphopeptides (PPPs) against hydrogen peroxide (H2O2)-induced oxidative stress were evaluated in an in vitro assay using human intestinal epithelial cells. Caco-2 cells were stimulated with 1 mM H2O2 for 6 h, and the secretion of IL-8, a proinflammatory mediator, was determined by ELISA as a biomarker of oxidative stress. The inhibition of H2O2-induced IL-8 secretion from Caco-2 cells was observed by pretreatment for 2 h with PPPs, but not with phosvitin. PPPs also suppressed the formation of malondialdehyde in H2O2-treated Caco-2 cells. Furthermore, intracellular glutathione levels and glutathione reductase activity were elevated by the addition of PPPs. The protective effects of PPPs against H2O2-induced oxidative stress were almost the same as that of glutathione, and PPPs with a high content of phosphorus exhibited higher protective activity than PPPs without phosphorus; however, phosphoserine itself did not show any significant antioxidative stress activity. These findings suggest that oligophosphopeptides from hen egg yolk phosvitin possess novel antioxidative activity against oxidative stress in intestinal epithelial cells and that phosphorus and peptide structure seem to have a key role in the activity.  相似文献   

3.
A hydroponic experiment was carried out to determine the influence of replacing 20% of nitrate-N in nutrient solutions with 20 individual amino acids on growth, nitrate accumulation, and concentrations of nitrogen （N）, phosphorus （P）, and potassium （K） in pak-choi （Brassica chinensis L.） shoots. When 20% of nitrate-N was replaced with arginine （Arg） compared to the full nitrate treatment, pak-choi shoot fresh and dry weights increased significantly （P ≤ 0.05）, but when 20% of nitrate-N was replaced with alanine （Ala）, valine （Val）, leucine （Leu）, isoleucine （Ile）, proline （Pro）, phenylalanine （Phe）, methionine （Met）, aspartic acid （Asp）, glutamic acid （Glu）, lysine （Lys）, glycine （Gly）, serine （Ser）, threonine （Thr）, cysteine （Cys）, and tyrosine （Tyr）, shoot fresh and dry weights decreased significantly （P ≤ 0.05）. After replacing 20% of nitrate-N with asparagine （Asn） and glutamine （Gin）, shoot fresh and dry weights were unaffected. Compared to the full nitrate treatment, amino acid replacement treatments, except for Cys, Gly, histidine （His）, and Arg, significantly reduced （P ≤0.05） nitrate concentrations in plant shoots. Except for Cys, Leu, Pro, and Met, total N concentrations in plant tissues of the other amino acid treatments significantly increased （P ≤ 0.05）. Amino acids also affected total P and K concentrations, but the effects differed depending on individual amino acids. To improve pak-choi shoot quality, Gln and Asn, due to their insignificant effects on pak-choi growth, their significant reduction in nitrate concentrations, and their increase in macroelement content in plants, may be used to partially replace nitrate-N.  相似文献   

4.
We investigated the effect of arbuscular mycorrhiza (AM) on amino acid concentration and composition of maize plants under low‐temperature stress. The AM plants had higher amino acid concentrations than the non‐AM pants. The concentrations of Thr, Lys, Gly, Ala, His, and Ile of the AM plants were higher than non‐AM plants. The results show that low‐temperature stress decreased the concentrations of amino acids and altered their composition.  相似文献   

5.
以20个大杯香菇品种和辐射选育新株系为材料, 分析了大杯香菇品种和辐射选育新株系蛋白质及其构成的17种氨基酸含量间的多元相关、回归和聚类关系, 并采用生物统计方法分析品种和新株系的蛋白质及各种氨基酸间的关系。结果表明: 大杯香菇辐105号新株系子实体中天门冬氨酸、苏氨酸、甘氨酸、丙氨酸、胱氨酸、缬氨酸、异亮氨酸、苯丙氨酸、蛋白质含量最高, 与部分品种和新株系子实体间差异显著或极显著, 且大多数氨基酸间及其与蛋白质含量之间存在显著或极显著正相关关系; 各种氨基酸与蛋白质含量之间分别有5种呈一次曲线关系, 10种呈二次曲线关系, ２种呈三次曲线关系; 采用系统聚类的方法可将蛋白质及17种氨基酸含量聚为4个大类, 对每类中的典型性状如精氨酸、亮氨酸、胱氨酸和蛋氨酸含量进行优化, 可有效提高大杯香菇品质育种中蛋白质构成的改良效率。  相似文献   

6.
Oxidative stress is involved in the initiation and propagation of chronic intestinal pathologies. Bioactive peptides such as egg yolk-derived phosvitin phosphopeptides (PPP3) have been previously shown to reduce in vitro oxidative stress by up-regulating glutathione synthesis and antioxidant enzyme activities. Peptide and gene expression profile analysis of the PPP3 peptides can provide insight into structures involved in signal transduction mechanisms in the antioxidative stress response. The objectives of this research were to identify the PPP3 amino acid sequences before and after simulated gastrointestinal digestion and to assess the genes influenced by PPP3. Peptide sequences were analyzed using ESI Q-TOF-MS/MS, and the expression profile of 84 human oxidative stress and antioxidant defense genes were analyzed. Undigested PPP3 was composed of three main peptides: GTEPDAKTSSSSSSASSTATSSSSSSASSPNRKKPMDE (phosvitin-PV residues 4-41), NSKSSSSSSKSSSSSSRSRSSSKSSSSSSSSSSSSSSKSSSSR (PV residues 155-197), and EDDSSSSSSSSVLSKIWGRHEIYQ (PV residues 244-257) and their fragments. There was limited degradation of PPP3 after gastrointestinal digestion as deduced from the fragment sizes of digested PPP3, which ranged from 5 to 32 amino acids. These fragments were rich in contiguous serines and, in some cases, monoesterified with phosphate. Both undigested and digested PPP3 significantly reduced IL-8 secretion in H(2)O(2)-induced Caco-2 cells, indicating that antioxidative stress bioactivity is retained upon digestion. After PPP3 pretreatment, antioxidant genes associated with oxygen and reactive oxygen species (ROS) metabolism and cellular responses to chemical stimulus, oxidative stress, and ROS are up-regulated in the presence and absence of oxidative stress, thereby contributing to the prevention of intestinal oxidative stress and the promotion of gut health.  相似文献   

7.
Reduction of free radicals generated by Fe(II)/cumene-hydroperoxide (CumOOH) by amino acids (Gly, Cys, Met, His, and Trp) and proteins (bovine serum albumin (BSA), beta-lactoglobulin, and lactoferrin) was followed by electron spin resonance spectroscopy using alpha-phenyl-N-tert-butylnitrone (PBN), 2-methyl-2-nitrosopropane (MNP), and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as spin traps. The radical species detected were mostly carbon-centered radicals from CumOOH fragmentation (methyl/*H3 and ethyl/*H2CH3), although carbon-centered radicals originated from amino acids could be formed in the presence of Cys, Met, His, or Trp. All proteins and amino acids, except Cys, were effective at inhibiting generation of radicals from the Fe(II)/CumOOH system. Trp was the amino acid with the highest antiradical activity, followed by His > Gly approximately Met. Lactoferrin was the protein showing the most efficient inhibition of radical formation from the Fe(II)/CumOOH system, and BSA and beta-lactoglobulin were not significantly different in their antiradical activities. These results suggest that proteins with higher inhibitory activity on lipid oxidation promoted by transition metal catalytic decomposition of hydroperoxides should be those with elevated metal-chelating and radical-scavenging properties as well as low concentration and accessibility of reducing groups from amino acids capable of activating metals, such as sulfhydryl groups.  相似文献   

8.
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9.
The tastes of several bitter amino acids and their gamma-glutamyl derivatives were compared. The bitterness of Phe, Val, Leu, and His was reduced, sourness was produced, and preferences were increased by gamma-glutamylization. Because the effect of gamma-glutamylization of bitter amino acids was most obvious for Phe, which is an atypical bitter amino acid, an enzymatic method for the synthesis of gamma-glutamylphenylalanine (gamma-Glu-Phe) involving bacterial gamma-glutamyltranspeptidase was developed. The optimum reaction conditions were 200 mM Gln, 200 mM Phe, and 0.5 unit/mL GGT, pH 10.4. After 1.5-h of incubation at 37 degrees C, 140 mM gamma-Glu-Phe was obtained, the yield being 70%. gamma-Glu-Phe was purified on a Dowex 1x8 column and then identified by NMR.  相似文献   

10.
This study was conducted to evaluate the effects of grape-seed procyanidins in controlling weaning diarrhea using a rat model. Weaned rats were fed either the basal diet or basal diet supplemented with either 250 mg/kg grape-seed procyanidins or 2000 mg/kg ZnO. Treated rats had better performance with a reduced incidence of diarrhea (P < 0.05). Both ZnO and grape-seed procyanidins significantly reduced urinary lactulose to mannitol ratios (P < 0.05) and enhanced the mRNA and protein expression of the intestinal mucosal tight junction proteins Ocln/ZO-1 (P < 0.05). Grape-seed procyanidins increased the activities of SOD, GSH-Px, and GSH while decreasing the level of MDA in the intestinal mucosa (P < 0.05). Furthermore, an in vitro investigation revealed that supplementation with grape-seed procyanidins in IEC-6 intestinal epithelial cells significantly enhanced the expression of Ocln/ZO-1 under H(2)O(2)-induced oxidative stress. Collectively, these results indicate that grape-seed procyanidins have the potential to prevent weaning diarrhea by reducing intestinal permeability and improving antioxidant indices.  相似文献   

11.
Anticancer compound screening of natural products using tumor cell lines has been commonly used to identify anticancer drugs. Two highly significant anticancer drugs, paclitaxel (Taxol) and camptothecin, were discovered using tumor cell lines by the U.S. National Cancer Institute (NCI) screening program of plants. It has been recently reported that the inhibition of cancer cell proliferation by fruit extracts was indirectly caused by phenolic-induced H(2)O(2) production in the cell culture media, suggesting that many previously reported effects of flavonoids and phenolic compounds on cultured cells might be from an artifact of H(2)O(2)-induced oxidative stress. The objective of the present study was to determine if apple extracts induced H(2)O(2) formation in common cell culture media and to investigate if the antiproliferative activity of apple extracts was due to phenolic-induced H(2)O(2) formation. It is reported here that apple extracts did not induce H(2)O(2) formation in WME, DMEM, or DMEM/Ham F12 media with the cell culture conditions tested. These same extracts inhibited proliferation of HepG(2) and Caco-2 cells. Therefore, antiproliferative activity of apple extracts was not due to the phenolic-induced H(2)O(2) production in cell culture media. In addition, H(2)O(2) added to the culture medium at 100 microM did not cause inhibition of cell proliferation in either HepG(2) liver cancer cells or Caco-2 colon cancer cells in vitro.  相似文献   

12.
Although chlorogenic acid (CHA) easily reaches a millimolar level in the gastrointestinal tract because of its high concentration in coffee and fruits, its effects on intestinal epithelial cells have been little reported. We investigated in this study the down-regulative effects of 5-caffeoylquinic acid (CQA), the predominant isomer of CHA, on the H(2)O(2-) or TNF-alpha-induced secretion of interleukin (IL)-8, a central pro-inflammatory chemokine involved in the pathogenesis of inflammatory bowel diseases, in human intestinal epithelial Caco-2 cells. After the cells had been pre- and simultaneously treated with CQA, the oversecretion of IL-8 and overexpression of its mRNA induced by H(2)O(2) were significantly suppressed in a dose-dependent manner in the range of 0.25-2.00 mmol/L. We further found that a metabolite of CQA, caffeic acid (CA), but not quinic acid, significantly inhibited the H(2)O(2)-induced IL-8 secretion and its mRNA expression in the same dose-dependent manner. Both CQA and CA suppressed the TNF-alpha-induced IL-8 secretion as well. Caffeic acid at 2.00 mmol/l was able to absolutely block the H(2)O(2)- or TNF-alpha-induced oversecretion of IL-8 in Caco-2 cells. However, CQA and CA did not suppress the TNF-alpha-induced increase in the IL-8 mRNA expression, indicating that the suppressive mechanisms are different between TNF-alpha-induced and H(2)O(2)-induced IL-8 production models. These results suggest that the habit of drinking coffee and/or eating fruits with a high CHA content may be beneficial to humans in preventing the genesis of inflammatory bowel diseases.  相似文献   

13.
Plants can take up intact amino acids, even in competition with soil microbes, yet we lack detailed information on which amino acids dominate the soil and whether amino acid composition varies seasonally. This study tested the hypotheses that 1) the pool of amino acid N is generally larger than inorganic N; 2) temporal changes in the concentration of amino acid N is related to changes in the size of the microbial N pool; and 3) amino acid N is dominated by simple, neutral amino acids during warm months, whereas during cold months the amino acid N is dominated by more complex aromatic and basic amino acids. Approximately every month for two years we collected soil from a temperate, sub-alpine grassland in the Snowy Mountains of Australia. We quantified exchangeable pools of amino acids, nitrate and ammonium in 1 M KCl extracts. Microbial N was quantified by chloroform fumigation. Averaged across the 21 monthly samples, nitrate was 13% of the quantified pool of soluble non-protein N, ammonium was 34% and amino acid N was 53%. These data are consistent with our hypothesis that the pool of amino acid N is larger than inorganic N. There was substantial variation between months in concentrations of amino acids and inorganic N, but no clear temporal pattern. Microbial N did not vary between months, and thus changes in amino acid N were unrelated to microbial N. Principal components analysis indicated multivariate groupings of the different pools of N that were broadly indicative of function and/or biosynthetic relationships. Thus PCA identified a grouping of aromatic amino acids (Phe and Try) with amino acids derived from oxaloacetate (Asp, Ala, Val, Leu, Ile), and a second group comprising microbial N, nitrate and glycine. The pool of exchangeable amino acid N was dominated by Arg (26% of amino N) Val (20%) Gln (18%), Try (8%) and Asn (8%). Contrary to our hypothesis, the composition of the amino acid pool did not vary in a consistent way between months, and there was no evidence simple amino acids were relatively more abundant in warm months and complex amino acids in cool months.  相似文献   

14.
Protein hydrolysates were prepared as a natural flavor stock from the red hake (Urophycis chuss) headed-gutted (H&G) mince and frame mince using commercial enzymes, Flavourzyme and Savorase, at the natural pH of fish (6.8) and the water/fish ratio of 2:5. The addition of 1.5% NaCl and 0.4% STPP improved the flavor quality of the hydrolysate by masking bitterness and off-flavor. A 6 h hydrolysis of H&G mince with Flavourzyme yielded a hydrolysate of the highest acceptability. Hydrolysis increased the concentration of most free amino acids except Arg and His. Leu, Lys, and Arg were predominant free amino acids in the hydrolysates, whereas Leu and Arg were major ones in the cooking juice. The concentration of Glu responsible for umami taste was increased by 6-9 times upon hydrolysis. Hydrolysates contained higher percentages of free amino acids giving both umami and sweet tastes than did cooking juice.  相似文献   

15.
通过田间试验研究了施氮量和穗粒肥比例对稻米氨基酸和蛋白质含量及Fe、Zn、Cu、Mn、Mg、Ca含量的影响。结果表明,稻米氨基酸和蛋白质含量均随着施氮量和穗粒肥比例的提高而增加,但施氮量和穗粒肥比例对氨基酸含量的影响程度因品种和氨基酸种类而异。合系39的氨基酸含量受施氮量和穗粒肥比例的影响较滇屯502的大;His、Val、Gly、Pro和Lys受施氮量和穗粒肥比例的影响较大,Ile、Arg、Asp和Glu受施氮量和穗粒肥比例的影响较小。稻米中Fe、Zn、Cu、Mn、Mg、Ca的含量和产量均随着施氮量的增加先上升后下降;从稻谷和蛋白质的产量、6种矿质元素的含量和产量看,供试粳型品种合系39的适宜施氮量较籼型品种滇屯502高。  相似文献   

16.
Interactions between a well-characterized protein, beta-lactoglobulin, and two flavor compounds, beta-ionone and gamma-decalactone, were studied by 2D NMR spectroscopy. NMR spectra were recorded in aqueous solution (pH 2.0, 12 mM NaCl, 10% D(2)O) under conditions such that beta-lactoglobulin is present in a monomeric state. TOCSY and NOESY spectra were recorded on the protein and the complexes between protein and ligands. The spectra of the NH-CH(alpha) region showed the cross-signals due to the coupling between N- and C-bonded protons in the polypeptide backbone. The observed chemical shift variations in the presence of ligands can be assigned to changes in the protein conformation. It appears that the side chains of several amino acids are affected by binding of gamma-decalactone point into the central cavity (Leu46, Ile56, Met107, and Gln120), whereas binding of beta-ionone affects amino acids located in a groove near the outer surface of the protein (Leu104, Tyr120, and Asp129), as illustrated by molecular visualization. This NMR study provides precise information of the location of binding and confirms the existence of two different binding sites for aroma compounds on beta-lactoglobulin, which was suggested in previous competition studies by fluorometry or affinity chromatography and by structural information obtained from infrared spectroscopy.  相似文献   

17.
Abstract

This project studied the amino acid composition of samples taken from an experiment of in situ incubation of plant debris, mixed with mineral earth, to identify changes during decomposition. Medicago sativa debris, and Eucalyptus globulus and Pinus halepensis ground litter, were mixed with a OM‐poor mineral earth, and buried in the soil at 5, 20, and 40 cm depth, for 2 years. The total amino acid composition of the final samples was compared with that of the initial ones. The amino acid composition of the several initial mixtures was quite similar. Also, the differences between initial and incubated samples were small, but still large enough to detect consistent changes. The pattern of change was consistent for only nine amino acids: Gly consistently increased, whereas Lys, His, Leu, and (to a lesser extent) Arg, Tyr, Phe, Ser, and Tau consistently decreased. The ratio Gly/(Lys+His+Leu+Arg+Tyr+Phe+Ser) is taken as the amino acid signature (AaS). This ratio increased from about 0.30–0.35 in the undecomposed mixtures, to about 0.55–0.60 after 2 years of field decomposition, and the comparison with data from other authors suggests that it could be a useful indicator of the degree of biochemical evolution of nitrogen compounds in soil samples. In contrast, changes in the traditional groups of amino acids, i.e., acid, basic, neutral, and sulfur (S)‐containing, were hardly detectable.  相似文献   

18.
The citrus flavanones hesperidin, hesperetin, and neohesperidin are known to exhibit antioxidant activities and could traverse the blood-brain barrier. H2O2 formation induces cellular oxidative stress associated with neurodegenerative diseases. In this study, protective effects of pretreatments (6 h) with hesperidin, hesperetin, and neohesperidin (0.8, 4, 20, and 50 microM) on H2O2-induced (400 microM, 16 h) neurotoxicity in PC12 cells were evaluated. The results showed that hesperetin, hesperidin, and neohesperidin, at all test concentrations, significantly ( p < 0.05) inhibited the decrease of cell viability (MTT reduction), prevented membrane damage (LDH release), scavenged ROS formation, increased catalase activity, and attenuated the elevation of intracellular free Ca2+, the decrease of mitochondrial membrane potential (except those of 0.8 microM neohesperidin-treated cells) and the increase of caspase-3 activity in H2O2-induced PC12 cells. Meanwhile, hesperidin and hesperetin attenuated decreases of glutathione peroxidase and glutathione reductase activities and decreased DNA damage in H2O2-induced PC12 cells. These results first demonstrate that the citrus flavanones hesperidin, hesperetin, and neohesperidin, even at physiological concentrations, have neuroprotective effects against H2O2-induced cytotoxicity in PC12 cells. These dietary antioxidants are potential candidates for use in the intervention for neurodegenerative diseases.  相似文献   

19.
吴恩芸  任稳稳  李耀东  刘丽霞  曹忻  张丽 《核农学报》2019,33(10):1940-1948
为探究中国荷斯坦牛Toll样受体1(TLR1)基因与中国荷斯坦牛乳房炎抗性的关联性,以中国荷斯坦牛为试验对象,构建DNA混合池,采用PCR扩增和直接测序法对中国荷斯坦牛TLR1基因进行单核苷酸多态性(SNP)检测,从而筛选出对中国荷斯坦牛免疫方面有显著影响的SNPs位点,同时应用在线软件对中国荷斯坦牛TLR1基因编码的蛋白质进行功能预测。结果表明,中国荷斯坦牛TLR1基因编码727个氨基酸,组成了一种不稳定的水溶性蛋白,蛋白质二、三级结构均以α-螺旋为主;PCR扩增后,在扩增片段处共发现8个SNPs位点,分别为A61T-TLR1、C632A-TLR1、C1408T-TLR1、C1451T-TLR1、A1461G-TLR1、A1475C-TLR1、G1550A-TLR1、G1596A-TLR1,其中A61T-TLR1、C632A-TLR1、C1408T-TLR1、A1461G-TLR1、G1596A-TLR1属错义突变,分别由原来的赖氨酸(Lys)、苯丙氨酸(Phe)、丙氨酸(Ala)、异亮氨酸(Ile)、缬氨酸(Val)突变为甲硫氨酸(Met)、亮氨酸(Leu)、缬氨酸(Val)、缬氨酸(Val)、异亮氨酸(Ile),SNPs位点的等位基因频率在突变前后均存在差异。DNA池结合直接测序技术检测到TLR1基因8个SNPs位点,可作为中国荷斯坦牛乳房炎的遗传标记进行深入研究;蛋白质功能预测结果表明,有多种与免疫相关的因子几率较高。本研究结果为中国荷斯坦牛在分子领域的抗病育种提供了理论依据。  相似文献   

20.
The effects of the addition of amino acids and peptides on the oxidation of eicosapentaenoic acid ethyl ester (EPE) encapsulated by maltodextrin (MD) were investigated. The encapsulated lipid was prepared in two steps, that is, by mixing of EPE with MD solutions (+/-amino acids and peptides) to produce emulsions and freeze-drying of the resultant emulsions. The addition of amino acids and peptides improved the oxidation stability of EPE encapsulated with MD, and the inhibition of lipid oxidation by the amino acids and peptides was more effective at 70% relative humidity (RH). Met, Arg, and Trp were effective amino acids for antioxidation at RH = 10 and 40%, whereas at RH = 70%, His was the most effective amino acid, preventing the oxidation of EPE almost perfectly. Carnosine also exhibited a strong antioxidant effect at RH = 70%, but the effect of anserine was inferior. The addition of Met + Trp or Met + Arg inhibited the oxidation of EPE encapsulated with MD at RH = 40%. Cys accelerated the oxidation of EPE, indicating that the thiyl radical may act as a pro-oxidant. No close relationship was observed between the radical scavenging abilities of amino acids and peptides measured in the aqueous diphenylpicrylhydrazyl solution and their antioxidative effects in the powdery system. It is possible that the radical-scavenging ability of amino acids and peptides detected by ESR in the powder system is responsible for the antioxidative activity of these compounds.  相似文献   

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