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1.
Quillaja saponin is the extract from the balk of a South American tree, and it is considered to modulate immunological responses. We hypothesized that Quillaja saponin may change allergy-associated cytokine profile and antigen-specific immune responses. The purpose of this study is to investigate whether Quillaja saponin can suppress ovalbumin (OVA)-induced IgE-mediated allergic responses through promoting a dominant Th1 immune response. The spleen cells from BALB/c mice, which were primed by OVA, were used for an in vitro challenge test. The level of total and OVA-specific IgE, IL-4, IFN-gamma, and IL-12 was determined by enzyme-linked immunosorbent assay (ELISA). BALB/c mice were orally administered with saponin for 35 days. The mice were immunized intraperitoneally with OVA on days 14 and 21. After intraperitoneal challenge with OVA on day 35, anaphylactic symptoms were monitored. Total and specific IgE and IgG, specific IgG1 and IgG2a, and histamine levels in serum were analyzed by ELISA. The increase of IL-12 and IFN-gamma levels was observed in the presence of Quillaja saponin, while the IL-4 level was decreased. Furthermore, Quillaja saponin suppressed total and OVA-specific IgE secretion in spleen cells. Balb/c mice that were orally administered Quillaja saponin exhibited lower total and OVA-specific IgE and OVA-specific IgG secretions, whereas total IgG levels remained unchanged. Suppression of OVA-specific IgG1 and an increase of OVA-IgG2a were observed in mice fed saponin. Quillaja saponin also decreased serum histamine levels and diminished anaphylactic symptoms. The present study indicates that Quillajasaponin can suppress allergen-specific IgE-mediated reactivity in a murine model of food allergy, which results from shifting from a Th2-dominated to a Th1-dominated immune response.  相似文献   

2.
The emergence of egg allergy has had both industrial and clinical implications. In industrialized countries, egg allergy accounts for one of the most prevalent food hypersensitivities, especially in children. Atopic dermatitis represents the most common clinical manifestation in infancy; however, the range of clinical signs is broad and encompasses life-threatening anaphylaxis. The dominant egg allergens are proteins and are mainly present in the egg white, for example, ovalbumin, ovomucoid, ovotransferrin, and lysozyme. However, egg yolk also displays low-level allergenicity, for example, alpha-livetin. Strict avoidance of the offending food remains the most common recommendation for egg-allergic individuals. Nevertheless, the omnipresence of egg-derived components in prepackaged or prepared foods makes it difficult. Therefore, more efficient preventive approaches are investigated to protect consumers from inadvertent exposure and ensuing adverse reactions. On the one hand, commercial kits have become readily available that allow for the detection of egg contaminants at trace levels. On the other hand, attempts to produce hypoallergenic egg-containing products through food-processing techniques have met with promising results, but the approach is limited due to its potentially undesirable effects on the unique functional and sensory attributes of egg proteins. Therefore, the development of preventive or curative strategies for egg allergy remains strongly warranted. Pilot studies have suggested that oral immunotherapy (IT) with raw or cooked preparations of egg may represent a safe alternative, immediately available to allergic subjects, but remains applicable to only nonanaphylactic patients. Due to the limitations of conventional IT, novel forms of immunotherapy are sought based on information obtained from the molecular characterization of major egg allergens. In the past decade, promising approaches to the treatment and prevention of egg allergy have been explored and include, among others, the production of hypoallergenic recombinant egg proteins, the development of customized peptides, and bacterial-mediated immunotherapy. Nonspecific approaches have also been evaluated, and preliminary trials with the use of probiotic bacteria have yielded encouraging results. The current understanding of egg allergens offers novel approaches toward the making of food products safe for human consumption and the development of efficient immunotherapeutic strategies.  相似文献   

3.
Riboflavin binding protein (RfBP) is a minor protein in hen egg; its potential involvement in egg allergy has seldom been studied. The aim of this work was to investigate the IgE binding capacity of RfBP before and after simulated gastrointestinal digestion. It was shown that digestion of RfBP mainly occurred during the gastric phase. The protein fragments resulting from the subsequent duodenal phase remained linked through disulfide bonds. Both the intact protein and its digests were subjected to inhibition ELISA with sera obtained from patients allergic to egg. The results revealed significant IgE binding to intact RfBP, whereas the digests showed reduced but substantial IgE binding levels, with serum-to-serum variability. The RfBP digests were then subjected to immunoblot with allergic patients' sera, and the IgE-reactive peptides were further analyzed by MALDI-TOF/TOF mass spectrometry for sequence determination. The RfBP sequence 41-84 was identified as a novel IgE binding peptide in patients allergic to egg.  相似文献   

4.
Hen's egg allergy represents one of the most common and severe IgE-mediated reactions to food in infants and young children. It persists, however, in many cases also lifelong. Therefore, the aim of this study was the detailed analysis of a technological process used to reduce the allergenic potential of hen's egg. The investigation focused on the pasteurized egg as starting material, intermediate, and final products of a nine-step manufacturing process performed for use of eggs in convenience products appropriate for allergic individuals. The steps consisted of a combination of various heat treatments and enzymatic hydrolyses. The alterations were controlled by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting, enzyme allergosorbent test (EAST) inhibition, and mass spectrometry. Thereby it could be demonstrated that the allergenic potential of the raw material was reduced from step to step, and despite the known stability against heat and proteolysis of certain egg proteins, the total allergenic potential was finally below 1/100 that of the starting material without a significant change in texture and flavor as evaluated in various products.  相似文献   

5.
刺苋是一种外来入侵植物,刺苋花粉现已成为我国华南地区的重要过敏原,且刺苋花粉变应原易与其他过敏原交叉反应。为研究刺苋花粉的过敏性,以刺苋花粉为研究对象对其进行致敏原纯化,再利用BALB/c小鼠进行腹腔注射,致敏滴鼻激发建立BALB/c小鼠动物过敏评价模型。通过对小鼠鼻部症状观察及评分,鼻腔分泌物涂片染色观察和血清中小鼠组胺和Ig E含量的测定,以及对小鼠解剖后肺部HE染色观察来确定小鼠的致敏剂量。结果表明,小鼠体内Ig E含量随注射剂量的增加呈线性增长的趋势,在注射量为75μg时达到最大值;小鼠体内组胺含量在低剂量注射时呈线性增长趋势,在注射量达到38μg后组胺含量变化趋于平缓;75μg注射量可引起小鼠明显的过敏反应,且导致小鼠肺部炎症反应。本研究对刺苋花粉进行过敏性评价研究,为全面进行外来入侵植物的健康风险评价做了一定补充。  相似文献   

6.
The physicochemical and functional properties of ultraviolet (UV)-treated egg white protein (EW) and sodium caseinate (SC) were investigated. UV irradiation of the proteins was carried out for 30, 60, 90, and 120 min. However, the SC samples were subjected to extended UV irradiation for 4 and 6 h as no difference was found on the initial UV exposure time. Formol titration, SDS-PAGE, and FTIR analyses indicated that UV irradiation could induce cross-linking on proteins and led to improved emulsifying and foaming properties (P < 0.05). These results indicated that the UV-irradiated EW and SC could be used as novel emulsifier and foaming agents in broad food systems for stabilizing and foaming purposes.  相似文献   

7.
The objective of this study was to assess the antiallergic effect of fermented milk prepared, respectively, with Streptococcus thermophilus MC, Lactobacillus acidophilus B, Lactobacillus bulgaricus Lb, L. bulgaricus 448, and Bifidobacterium longum B6. Female BALB/c mice fed fermented milk were immunized intraperitoneally with ovalbumin (OVA)/complete Freund's adjuvant (CFA) to evaluate the immune response by observing the secretion of cytokines IL-2, IL-4, and IFN-gamma and serum antibody IgE. The results showed that supplementation with lactic acid bacteria fermented milk did not significantly change the IL-2 spontaneous and OVA-stimulated secretions of splenocytes. However, both spontaneous and OVA-stimulated secretions of splenocytes from mice fed lactic acid bacteria fermented milk showed significantly (P < 0.05) lower levels of IL-4 (Th2 cytokine) than those from OVA/CFA-immunized mice fed non-fermented milk (OVA/CFA-milk group). The spontaneous secretion of IFN-gamma (Th1 cytokine) by splenocytes from mice fed L. bulgaricus 448 or L. bulgaricus Lb fermented milk significantly increased as compared to that from the OVA/CFA-milk group. The results showed that the ratios of IFN-gamma to IL-4 of both spontaneous and OVA-stimulated secretions in splenocytes from mice fed lactic acid bacteria fermented milk increased significantly as compared to that of PBS- or OVA/CFA-milk groups. The serum levels of OVA-specific IgE in fermented milk fed groups, especially the group fed S. thermophilus MC fermented milk, were significantly lower than those in the OVA/CFA-milk group through a 6 week feeding experiment. The results showed that milk fermented with lactic acid bacteria demonstrated in vivo antiallergic effects on OVA/CFA-immunized mice via increasing the secretion ratio of IFN-gamma/IL-4 (Th1/Th2) by splenocytes and decreasing the serum level of OVA-specific IgE.  相似文献   

8.
The market of specialty eggs, such as omega-3-enriched eggs, organic eggs, and free-range eggs, is continuously growing. The nutritional composition of egg yolk can be manipulated by feed diet; however, it is not known if there is any difference in the composition of egg white proteins among different egg varieties. The purpose of the study was to compare the egg white proteins among six different egg varieties using proteomics analysis. Egg white proteins were analyzed using two-dimensional gel electrophoresis (2-DE), and 89 protein spots were subjected to LC-MS/MS. A total of 23 proteins, belonging to Gallus gallus , were identified from 72 detected protein spots. A quiescence-specific protein precursor in egg white was identified for the first time in this study. Significant differences in the abundant levels of 19 proteins (from 65 protein spots) were observed among six egg varieties. Four proteins, ovalbumin-related protein Y, cystatin, avidin, and albumin precursor, were not different among these six egg varieties. These findings suggest that the abundance, but not the composition, of egg white proteins varied among the egg varieties.  相似文献   

9.
A 35-day experiment was conducted to evaluate the effect of selenium-enriched probiotics (SP) on laying performance, egg quality, egg selenium (Se) content, and egg glutathione peroxidase (GPX) activity. Five hundred 58-week-old Rohman laying hens were randomly allotted to 5 dietary treatments of 100 each. Each treatment had 5 replicates, and each replicate had 5 cages with 4 hens per cage. The SP was supplemented to a corn-soybean-meal basal diet at 3 different levels that supplied total Se at 0.2, 0.5, and 1.0 mg/kg. The basal diet served as a blank control, while the basal diet with supplemental probiotics served as a probiotics control. The results showed that dietary SP supplementation not only increased (p < 0.05) the rate of egg laying, day egg weight, mean egg weight, egg Se content, and egg GPX activity but also decreased (p < 0.05) the feed:egg ratio and egg cholesterol content. The egg Se content was gradually increased (p < 0.05) along with the increasing level of dietary Se. The SP supplementation also slowed down (p < 0.05) the drop of Haugh units (HU) of eggs stored at room temperature. The egg GPX activity had a positive correlation (p < 0.01) with egg Se content and a negative correlation (p < 0.01) with egg HU drop. These results suggested that Se contents, GPX activity, and HU of eggs were affected by the dietary Se level, whereas the egg-laying performance and egg cholesterol content were affected by the dietary probiotics. It was concluded that this SP is an effective feed additive that combines the organic Se benefit for hen and human health with the probiotics benefit for laying hen production performance. It was also suggested that the eggs from hens fed this SP can serve as a nutraceutical food with high Se and low cholesterol contents for both healthy people and patients with hyperlipidemia, fatty liver, or cardiovascular disease.  相似文献   

10.
Dehulled adlay is known as a natural Chinese medicine having antiallergic activity, although its mechanism remains unclear. This study examined the effects of dehulled adlay on antigen-specific antibody and cytokine production. Mice were immunized three times with ovalbumin (OVA) in alum adjuvant. It was found that oral administration of dehulled adlay in mice suppressed the production of IgE against OVA antigen. Serum anti-OVA IgG(2a) antibody levels were significantly increased in mice after oral administration of dehulled adlay. Furthermore, the production of IL-2 by OVA-stimulated splenocytes was augmented in dehulled adlay-fed mice. Although dehulled adlay had no effect on the serum anti-OVA IgG(1) antibody levels, it had a great capacity to reduce IL-5 secretion by means of OVA-stimulated splenocytes. Hydrothermal processes, including steaming and extrusion cooking, did not change the capacity of dehulled adlay to suppress IgE production. Three fractions of dehulled alday, including methanolic extract, warm water extract, and residue, were obtained. The methanolic extract exhibited the greatest capacity to reduce anti-OVA IgE production. These results suggest that dehulled adlay has a modulating ability to shift the balance from Th2 to Th1 dominance in the T cell mediated immune system and may be beneficial for the treatment of allergic disorders.  相似文献   

11.
d-Psicose (Psi) might be an ideal sucrose (Suc) substitute for food products due to its sweet taste, easy processing, and functional properties (noncaloric and low glycemic response). In the present study, the effects of Psi on foaming properties of egg white (EW) protein and the quality of butter cookies were analyzed to find a better use of Psi in aerated food systems. The results showed that Psi could improve the foaming properties of EW protein with increasing whipping time in comparison to Suc and d-fructose (Fru). The addition of Psi to butter cookies, as partial replacement of Suc, had no influence on the cook loss while significantly contributing to a color change of the cookie crust through a nonenzymatic browning reaction. Furthermore, Psi-containing cookies possessed the highest antioxidant capacity in all tested cookies using two assays of radical scavenging activity and ferric reducing power. It was found that there was a close correlation between the crust color and the antioxidant activity of the cookie. The results suggest that the addition of Psi enhanced the browning reaction during cookie processing and, consequently, produced a strong antioxidant activity.  相似文献   

12.
电解水技术是果蔬采后保鲜和商品化处理的热点技术,该研究对电解水抑制微生物、去除农药残留和提质延时保鲜3个方向开展技术总结和机理研究综述,并从电解水技术在采后果蔬的处理方式和专利申请方面对其应用性开展应用分析。总结发现,1）不同类型的电解水在果蔬采后保鲜领域研究不完善,酸性电解水较碱性电解水研究更丰富;2）酸性电解水是有效去除食源性致病细菌的农产品加工工程技术,但酸性电解水对果蔬腐烂真菌的抑制研究还不充分;3）电解水可以有效去除果蔬表面农药残留,在机磷农药上阐明了具体机理,对于有机氯、菊酯农药的降解研究不足;4）电解水处理可以有效提升果蔬的抗性、缓解果蔬低温贮藏冷害并抑制鲜切果蔬褐变;5）目前电解水应用方式较为单一,不适宜所有果蔬保鲜处理流程,技术专利申请较少。通过本文梳理归纳以期为电解水技术的工程技术应用拓展提供理论依据和参考。  相似文献   

13.
Characterization of high-pressure-treated egg albumen.   总被引：2，自引：0，他引：2  
Addition of NaCl or sucrose to egg albumen prior to high-pressure treatment (up to 10 min at 800 MPa) prevented insolubilization or gel formation after pressure treatment. As a consequence of protein unfolding, the treated albumen had increased viscosity but retained its foaming and heat-gelling properties. Susceptibility of egg albumen proteins to hydrolysis by trypsin increased dramatically after pressure treatment. The S-form of ovalbumin, the presence of which is an index of egg aging, was not found in any of the pressure-treated samples, which also did not display evidence for covalent protein aggregation. However, recognition of ovalbumin by an anti-ovalbumin antiserum was reduced to 40% of that of untreated sample.  相似文献   

14.
选用BalB/C乳鼠和成年BalB/C小鼠进行卡介苗（bacillus calmette-guerin, BCG）接种, 攻毒后用体外培养法观察脾细胞内病原生长特性以及用enzyme-linked immunospot (ELISPOT)方法检测脾细胞诱导表达γ-干扰素（interferon -γ,IFN-γ）和白细胞介素-4（interleukin -4,IL-4）的变化。结果显示,低剂量（2×103 cfu）BCG对7日龄乳鼠可产生100%的免疫保护,高剂量（4×104 cfu）BCG产生75%的免疫保护;而低剂量（2×103 cfu）BCG对35日龄小鼠产生的免疫保护为67%。低剂量（2×103 cfu）BCG诱导乳鼠产生以IFN-γ为主的Th1类细胞免疫反应明显增强,以IL-4为主的Th2类免疫反应降低;而高剂量（4×104 cfu ）BCG诱导产生的IFN-γ/IL-4均增多。低剂量（2×103 cfu）BCG接种诱导35日龄小鼠产生的IFN-γ/IL-4亦均增多。结果表明,卡介苗BCG对小鼠的保护率与BCG免疫剂量和免疫动物日龄间存在紧密的相关性,这种差异可能与BCG诱导产生的Th1/Th2类细胞免疫反应的变化有关。  相似文献   

15.
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   

16.
Chicken egg ovoinhibitor is a multidomain Kazal-type serine protease inhibitor with unknown function. Comparison of expression between different tissues indicated that ovoinhibitor is highly expressed in the magnum and liver followed by the uterus, which secrete egg white, egg yolk, and eggshell precursors, respectively. The results also revealed that ovoinhibitor expression is increased in the liver during sexual maturation followed by a subsequent decrease in mature hens. Ovoinhibitor was purified from the egg yolk plasma from nonfertilized eggs using two consecutive affinity chromatographies and gel filtration. Purified egg yolk ovoinhibitor was shown to inhibit trypsin and subtilisin. It was shown that purified egg yolk ovoinhibitor exhibited antimicrobial activities against Bacillus thuringiensis . The results suggest that this anti-protease plays a significant role in antibacterial egg defense against Bacillus spp., preventing contamination of table eggs (nonfertilized eggs) and protecting the chick embryo (fertilized eggs).  相似文献   

17.
The sulfhydryl (SH) content of egg white proteins (10% v/v or 9.64 mg of protein/mL) after heat (50-85 degrees C) and combined heat- and high-pressure treatments (100-700 MPa, 10-60 degrees C) was determined using 5',5-dithiobis (2-nitrobenzoic acid) (DTNB), both for the soluble fraction and the total protein fraction. Only irreversible changes were taken into account. Both physical treatments were performed at two pH levels: pH 7.6, corresponding to the pH of fresh egg white, and pH 8.8, corresponding to that of aged egg white. Both heat and combined heat- and high-pressure treatment resulted in an exposure of buried SH groups. These exposed SH groups were involved in the formation of disulfide bond stabilized protein aggregates, as shown by gel electrophoresis. Under severe processing conditions (above 70 degrees C at atmospheric pressure or above 500-600 MPa, depending on the temperature applied), a decrease in total SH content could be observed, probably due to the formation of disulfide bonds by oxidation, especially at alkaline pH when the thiolate anion was more reactive. The high degree of exposure of sulfhydryl groups, and subsequent oxidation and sulfhydryl-disulfide bond exchange reactions resulting in soluble aggregates, can explain why pressure-induced egg white gels are softer and more elastic than heat-induced ones. When pressure treatment was performed at low temperatures (e.g., 10 degrees C), a lower pressure was required to induce similar changes in the sulfhydryl content, as compared to higher temperatures (e.g., 25 degrees C), indicating an antagonistic effect between pressure and temperature in the domain studied (10-60 degrees C, 100-700 MPa). Treatment conditions resulting in extensive protein insolubilization were accompanied by a transfer of free sulfhydryl groups from the soluble to the insoluble protein fraction. These SH groups were mainly accessible to DTNB.  相似文献   

18.
Contribution of egg hatch inhibition in the overall reduction of Meloidogyne incognita numbers by Nemafric-BL phytonematicide was determined in vitro using a series of water-diluted phytonematicide solutions. Hatched juveniles were assessed at four different incubation periods. Thereafter, each phytonematicide solution was water-diluted 5 times and incubated for 5 days to evaluate the reversibility of egg hatch inhibition. At all exposure periods, except the shortest (24?h), concentration effects on egg hatch were highly significant with juvenile numbers versus increasing concentrations exhibiting quadratic relations. The models for the three consecutive exposure periods explain the quadratic relations by 95%, 94% and 98%, respectively. Results suggested that egg hatch inhibition was one of the mechanisms involved in reducing M. incognita population densities by Nemafric-BL phytonematicide.  相似文献   

19.
Changes in physicochemical properties of egg yolk were investigated after a treatment with phospholipase A 2 (PLA 2), where phospholipids are converted in lyso-phospholipids. Protein solubility and protein denaturation before and after modification by PLA 2 was monitored as well as the functionality of egg yolk by means of interfacial tension. Enzymatic treatment showed a significant impact on the properties of egg yolk with regard to protein solubility and denaturation behavior. To gain a closer insight, egg yolk was separated in its water-soluble fraction called plasma and the insoluble granules. Both fractions were separately modified by PLA 2. The granule fraction shows a higher protein solubility, and the plasma proteins show very high heat stability after modification by PLA 2. Hypotheses regarding related changes in the low-density lipoprotein (LDL) particles are discussed. Results suggest that significant differences in the functional properties of untreated and PLA 2-modified egg yolk do not primarily result from the existence of lyso-phospholipids but from structural changes in egg yolk granules and LDL particles.  相似文献   

20.
The quantitative determination of cholesterol in egg yolk by using an enzymatic test kit is described. Cholesterol in the egg yolk is extracted with other lipid components by methylene chloride-methanol (2 + 1) and is enzymatically determined after saponification of the lipid extract. The method is relatively rapid, simple, and accurate and gives results which agree with those obtained by using a gas-liquid chromatographic (GLC) method. The mean cholesterol content of egg yolk determined by the enzymatic and GLC methods was 1237 and 1240 mg/100 g, respectively.  相似文献   

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