致仔猪过敏性大豆抗原蛋白β-conglycinin单克隆抗体的制备与鉴定

研究以人工合成的对应于β-conglycinin分子α'亚基上的一段抗原表位肽(RPQHPER,78-84α')作为半抗原,与载体蛋白(OVA)交联后,作为免疫原制备了致仔猪过敏性大豆抗原蛋白β-conglycinin的单克隆抗体(Mab 6G4),并应用酶联免疫吸附等方法进行鉴定。结果表明,制备的单抗Mab 6G4属于IgG1;该抗体能与大豆β-conglycinin特异性结合,IC50为4.7 ng/mL,并对β-conglycinin表现出较强的亲和力,亲和常数达6.9×109 L/mol。因此,制备的单克隆抗体Mab 6G4为分析大豆制品中β-conglycinin的含量及探讨β-conglycinin对仔猪的致敏机理提供了一个潜在的分析工具。     

大豆β-伴大豆球蛋白研究进展

在大豆抗原蛋白的研究中,β-伴大豆球蛋白的研究比较重要。在其结构和特性方面,β-伴大豆球蛋白的α′亚基和该亚基上的Soymetide研究较为深入,并且摄入β-伴大豆球蛋白与体内甘油三酯含量有一定关系。很多研究表明,仔猪腹泻、犊牛腹泻的主要诱因来自于抗原性蛋白所引起的体内消化道免疫反应。不同的加工工艺如挤压膨化、乙醇浸提,可以降低β-伴大豆球蛋白对于机体的损害,本文还基于现在的研究提出了进一步的展望。     

β-伴大豆球蛋白对仔猪抗营养阈值的研究进展

β-伴大豆球蛋白等抗原蛋白热稳定性较强,其抗原活性难以完全去除,可导致仔猪等幼龄动物产生过敏反应,从而影响其生理健康、日粮养分消化利用和生产性能。目前针对不同大豆制品在畜禽生产中的应用已有大量研究,但大豆抗原蛋白在幼龄畜禽日粮中的安全剂量尚不明确。本文对β-伴大豆球蛋白的理化性质及对仔猪的致敏机制、大豆制品中β-伴大豆球蛋白含量及大豆制品在仔猪生产中的应用进行综述,并对β-伴大豆球蛋白在仔猪日粮中的安全剂量进行探讨。     

大豆球蛋白及β-伴大豆球蛋白的研究进展

大豆是一种高蛋白含量的作物,在畜禽养殖中多用作蛋白饲料,但其中含有的抗营养因子限制了大豆的使用。大豆球蛋白及β-伴大豆球蛋白是主要的抗原蛋白。本文介绍了大豆球蛋白及β-伴大豆球蛋白的结构、抗营养作用和抗原性的消除方法。     

大豆抗原蛋白对小鼠肠上皮细胞的影响

大豆中所含的抗原蛋白是引起幼龄动物发生过敏反应的重要原因之一。研究以自备分离纯化大豆球蛋白和β-伴球蛋白作为试验材料,以原代培养小鼠肠上皮细胞作为试验模型,研究0、1、5和10mg/mL纯化大豆球蛋白和β-伴球蛋白对小鼠肠上皮细胞完整性和免疫的影响。结果表明:超过5mg/mL大豆球蛋白和β-伴球蛋白能破坏小鼠肠上皮细胞完整性,抑制上皮细胞增殖。显著提高培养液乳酸脱氢酶(LDH)和谷草转氨酶(GOT)水平。大豆球蛋白和β-伴球蛋白能显著提高体外培养的小鼠肠上皮细胞炎性细胞因子(白介素-2(IL-2)、白介素-6(IL-6)、白介素-8(IL-8))的分泌,促使其发生过敏反应。     

大豆球蛋白、β-伴大豆球蛋白对反刍前犊牛致敏作用的研究

8头初生荷斯坦公犊牛,随机分为A、B两组,每组4头。分别饲喂含生全脂大豆粉的代乳料和全乳。1、3、7、10、14、18、22、26、30、34、38、42日龄早饲前采血5mL,分离血清,以提纯大豆球蛋白、β-伴大豆球蛋白及其相邻收集馏分(7S二峰、11S二峰)为抗原,采用ELISA方法测定血清中特异性抗体滴度。结果表明:A组犊牛自10日龄起全部开始腹泻,20日龄左右粪便中可见脱落的肠黏膜,而B组犊牛无腹泻发生;A组犊牛血清中各种大豆抗原蛋白的特异性抗体滴度均极显著地(P<0.01)高于B组;饲喂初乳后,3日龄血清抗体滴度出现一个峰值;在持续饲喂大豆蛋白的情况下,6周龄内血清抗体持续升高,未见下降趋势,其中7S二峰致敏性高于大豆球蛋白、β-伴大豆球蛋白和11S二峰;β-伴大豆球蛋白在30日龄前致敏性高于大豆球蛋白和11S二峰。     

大豆抗原蛋白对小鼠肠上皮细胞吸收功能的影响

大豆中所含的大豆球蛋白和β-伴球蛋白会导致幼龄动物对营养物质的吸收功能发生下降,进而出现腹泻等症状。试验以自备分离纯化大豆球蛋白和β-伴球蛋白作为试验材料,以原代培养小鼠肠上皮细胞作为试验模型,研究了0、1、5和10mg/mL纯化大豆球蛋白和β-伴球蛋白对小鼠肠上皮细胞Na+-K+-ATP酶及小肽转运蛋白1(PEPT1)和二价金属离子转运体(DMT1)表达的影响。结果表明:大豆球蛋白和β-伴球蛋白能增强小鼠肠上皮细胞Na+-K+-ATP酶活性,降低PEPT1和DMTl基因的表达量,而且β-伴球蛋白的作用明显大于大豆球蛋白。     

大豆抗原蛋白的基本结构及作用机理

本文阐述了大豆球蛋白和β-伴球蛋白的基本结构及其使动物产生腹泻的作用机理,说明了大豆抗原蛋白对动物的抗营养作用。     

大豆抗原蛋白β-伴大豆球蛋白抗酶解肽的分离纯化及其免疫活性鉴定

β-伴大豆球蛋白(β-conglycinin)是引起动物过敏反应的主要致敏原之一,经消化酶降解后仍存在具有免疫活性的抗酶解物质,目前它对动物的致敏机理和强度还没有确切定论。试验旨在分离纯化出β-伴大豆球蛋白抗酶解肽,为后续的体外试验提供刺激源,从而为研究抗酶解肽对机体的致敏作用及机制提供必要的条件。试验通过模拟体外环境,利用胃蛋白酶、胰蛋白酶消化β-伴大豆球蛋白,分析β-伴大豆球蛋白中主要的抗酶解肽段,并用β-伴大豆球蛋白致敏的兔血清免疫印迹试验检测抗酶解肽段的免疫活性,利用凝胶层析技术分离纯化β-伴大豆球蛋白抗酶解肽。结果表明:β-伴大豆球蛋白在胃蛋白酶、胰蛋白酶的连续消化下产生大量抗酶解的肽段,其中有3条主要的抗酶解肽段,分子量分别约为52、30、25 ku。52 ku含量相对较高,且均具有免疫活性。酶解产物经葡聚糖G-100凝胶层析分离纯化后,得到分子量为52 ku的抗酶解肽段纯品。     

大豆抗原蛋白研究进展

大豆抗原蛋白既是大豆的主要营养成分,又是大豆抗营养因子之一,是限制大豆及其制品在人类营养和动物饲料中利用的主要因素。鉴于此,对大豆抗原蛋白的研究具有重要的科研和应用价值。其中最主要的两类为大豆球蛋白和β-伴大豆球蛋白,同时也是大豆引起机体过敏反应和腹泻的主要成分。本文主要介绍了大豆抗原蛋白的种类及结构、大豆抗原蛋白的营养免疫学特点,并对今后的研究方向进行了初步探讨。     

商会自治的基石——商会自治规范研究

在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。     

癸氧喹酯干混悬剂含量测定的改进

采用高效液相色谱法测定癸氧喹酯干混悬剂的含量,在2-250μg/mL范围内,峰面积的常用对数与进样量浓度的常用对数呈良好的线性关系,R^2=1(n=5),平均回收率为99.24%~99.51%,RSD在0.05%~0.28%。此方法分析时间短,样品前处理简便、定量结果准确,重现性好,结果满意,为其质量控制提供了依据。     

猪毛色遗传的研究进展

本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。     

Comparison of 2 methods of centesis of the bursa of the biceps brachii tendon of horses

REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air.     

不同样本商品蜂蜜中硒含量的测定

用硝酸和高氯酸消化蜂蜜,使硒游离出来,在微酸性环境下,硒和2,3-二氨基萘(DAN)生成有较强荧光的物质,用环己烷萃取,在激发波长378nm,荧光波长518nm处测定其荧光强度。蜂蜜中硒含量范围:0.10～0.82μg/g。表明:蜂蜜应视为天然富硒营养品。     

乳酸杆菌益生作用机制的研究进展

乳酸杆菌作为益生菌广泛用于人和动物。本文综述了乳酸杆菌改善宿主健康的机制。乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道。文章重点讨论了乳酸杆菌表面成分（表面蛋白、脂磷壁酸和肽聚糖）与肠道受体（Ｃ型凝集素受体、Ｔｏｌｌ样受体和 Ｎｏｄ样受体）,阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制。     

Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF

Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo.     

Mechanism of Action of Probiotic Function of Lactobacilli

乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制.     

Evaluation of serum concentrations of biomarkers of skeletal metabolism and results of radiography as indicators of severity of osteochondrosis in foals

OBJECTIVE: To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses. ANIMALS: 43 Dutch Warmblood foals with varying severity of osteochondrosis. PROCEDURE: 24 foals were monitored for 5 months and 19 foals were monitored for 11 months. Monthly radiographs of femoropatellar-femorotibial and tibio-tarsal joints were graded for osteochondral abnormalities. Serial blood samples were assayed for 8 cartilage and bone biomarkers. At the end of the monitoring period, foals were examined for macroscopic osteochondrosis lesions. RESULTS: Temporal relationships were evident between certain serum biomarkers and osteochondrosis severity in foals during their first year. Biomarkers of collagen degradation (collagenase-generated neoepitopes of type-II collagen fragments, type-I and -II collagen fragments [COL2-3/4C(short)], and cross-linked telopeptide fragments of type-I collagen) and bone mineralization (osteocalcin) were positive indicators of osteochondrosis severity at 5 months of age. In foals with lesions at 11 months of age, osteochondrosis severity correlated negatively with COL2-3/4C(short) and osteocalcin and positively with C-propeptide of type-II procollagen (CPII), a collagen synthesis marker. Radiographic grading of osteochondrosis lesions significantly correlated with macroscopic osteochondrosis severity score at both ages and was strongest when combined with osteocalcin at 5 months and CPII at 11 months. CONCLUSIONS AND CLINICAL RELEVANCE: The ability of serum biomarkers to indicate osteochondrosis severity appears to depend on stage of disease and is strengthened with radiography. In older foals with more permanent lesions, osteochondrosis severity is significantly related to biomarker concentrations of decreased bone formation and increased cartilage synthesis.