国产年产3000吨谷朊粉生产线研制成功

由南京野生植物综合利用研究院与河南天冠集团共同研究开发的年产 30 0 0吨活性小麦谷朊粉生产线于 2 0 0 2年 8月 3日在河南天冠集团通过河南省与中华全国供销合作总社联合组织的鉴定。活性小麦谷朊粉又称活性面筋粉 ,是将小麦粉中的蛋白质分离提取并烘干而成的一种粉末状产品     

小麦精深加工产业发展概况

综述了小麦谷朊粉加工、小麦淀粉生产酒精工艺、小麦淀粉制糖、麦麸和麦胚加工等方面开发应用的研究进展,指出存在的问题,并提出相应的对策,旨在为小麦精深加工提供参考。     

朊病毒和朊病毒病研究进展

朊病毒病即海绵状脑病,是人和动物中的一类致死性中央神经系统疾病,近几年来在朊病毒病的致病机制及其诊断技术和防治策略方面取得了很大的研究进展.     

适合糖尿病患者食用的高粱馒头配方的研究

研究高粱馒头的工艺及品质,并通过正交试验对工艺进行了优化。结果表明：45.74%高粱粉、45.74%小麦粉、6.52%谷朊粉和57.5%水在35min的二次醒发时间下醒发,可以得到品质良好的高粱馒头,在这种配比下得到的馒头感官评分为86.28。经测定,该高粱馒头的血糖生成指数（GI）为57.07,属中GI值水平,适合糖尿病患者在日常饮食中食用。     

长头谷盗对6种寄主谷粉及其挥发物的行为反应

利用Y型嗅觉仪和四臂嗅觉仪,测定了长头谷盗Latheticus oryzae (Waterhouse)对6种寄主谷粉的行为趋性反应,采用固相微萃取和气质联用(GC-MS)分析了其中3种寄主挥发物组分和含量,并测定长头谷盗对其中7种挥发物单体标样在5个浓度下的行为学反应,以期明确谷物挥发物在长头谷盗寄主定向行为中所起的作用.结果显示,6种寄主挥发物对长头谷盗雌雄成虫均具有显著的引诱作用,且雌雄个体间差异不显著;6种寄主之间分组比较时,长头谷盗的引诱强弱均显著的表现为全麦粉＞黄豆粉＞玉米粉＞荞麦粉＞小米粉＞高粱粉.选择全麦粉、黄豆粉和玉米粉进行分析时,3种寄主挥发物具有不同的化学图谱,且挥发物的相对含量差异较大,黄豆粉挥发物总量大于全麦粉和玉米粉;从组分来看,全麦粉挥发物中主要为烯醛类(37.46％),黄豆粉挥发物中主要为醇类(45.24％)和醛类(27.06％),玉米粉挥发物种主要为烷烃类(39.58％).7种寄主挥发物标样(100 ～ 1600μL/mL)中,除甲酸正己酯、二十烷和正十四烷对长头谷盗始终具有引诱作用外,正己醇、正己醛和反式-2,4-癸二烯醛分别在200～800、400 ～ 800和400 ～ 800 μL/mL时,才具有引诱作用;而反式-2-癸烯醛在高浓度(1600 μL/mL)下对长头谷盗具有趋避作用.综合分析表明,挥发性物质在长头谷盗对不同寄主谷粉的选择时具有重要的行为导向作用,且挥发性化合物的组成及浓度影响其引诱效果.     

高效储粮杀虫涂料的研究

运用微胶囊技术把氰戊菊酯与毒死蜱原药包裹在囊中,然后与涂料制成0.5%、1.0%、2.0%、5.0%杀虫涂料,经试验,2.0%～5.0%的微胶囊杀虫涂料对谷蠹Rhyzoperthadominica F.、玉米象Sitophilus zeamais Motschulsy、赤拟谷盗Tribolium castanamensis L.杀灭率为100%,对书虱Atropus pulsatoria Linnaeus、螨Acarus类杀灭率在90%以上,1.0%的杀虫涂料对以上害虫杀灭率在90%以上,进口杀虫涂料对谷蠹、玉米象、赤拟谷盗杀灭率在85%以上,但对书虱、螨类无效.经成本核算,若采用3%新型杀虫涂料,成本仅为进口杀虫涂料的29.1～33.3%.     

阿尔茨海默病与PRNP突变体小鼠动物模型

阿尔茨海默病是由β淀粉样蛋白造成的人类神经损伤性痴呆病之一,目前尚无治疗办法。朊蛋白是β淀粉样蛋白的受体,是阿尔茨海默病发病过程的关键蛋白之一,具有传递神经毒性和保护神经细胞的双重作用。人朊蛋白编码基因(PNRP)多态性影响阿尔茨海默病的潜伏期和临床症状,而PRNP突变体小鼠的发现提升了动物模型在朊蛋白疾病研究中的应用价值,在一定程度上弥补了现有阿尔茨海默病动物模型的不足。本文总结了朊蛋白在阿尔茨海默病病理中的作用及PRNP突变对阿尔茨海默病的影响,并详细总结了PRNP突变体小鼠的发现及在蛋白沉淀样病变研究中的应用和价值,旨在为阿尔茨海默病动物模型研究提供理论参考。     

微管相关蛋白tau与朊蛋白的相互作用

微管相关蛋白tau参与了许多神经退行性疾病的发生, 其中包括一些人类可传播性海绵状脑病. 为了探讨tau与朊蛋白(PrP)之间可能存在的关系, 首先通过GST pull-down和免疫共沉淀等技术发现重组tau蛋白可通过微管结合区与来源于正常叙利亚仓鼠脑组织中的正常细胞膜朊蛋白(PrP^C)和羊瘙痒因子263K感染仓鼠脑组织的异常朊蛋白(PrPSc)相结合. 利用免疫共沉淀实验发现在正常和羊瘙痒因子感染的仓鼠脑组织中存在tau蛋白与PrPC和PrPSc的相互作用, 并且利用激光共聚焦方法检测到PrP和tau蛋白在CHO细胞内具有共定位的关系. 为了确定PrP与tau蛋白相互作用的部位, 构建了不同区域的PrP片段, 从而证明PrP与tau蛋白相互作用的区域位于PrP的N端序列(23~91 aa). PrP与tau蛋白分子间相互作用的直接实验证据提示tau蛋白可能参与PrP的正常生理功能以及朊病毒病的病理过程.     

靶向PrP及Aβ的治疗性抗体研究进展

朊病毒病与阿尔茨海默病具有蛋白质异常折叠的共同特征, 患者均有痴呆的症状, 但前者具有传染性, 而后者没有. 这引起人们的研究兴趣, 从不同角度开展了二者的比较研究. 近年来, 靶向其关键蛋白PrP和Aβ的免疫治疗研究进展很快. 本文结合实际研究工作, 着眼于治疗性抗体的疾病靶向性和构象特异性等主要特征, 综述了针对PrP和Aβ治疗性抗体研究中的新视点和新策略, 以期为探索这两种疾病的共同机制及治疗方法提供参考.     

抗牛PrP多肽单克隆抗体的制备及其在牛PrP 检测中的应用

为获得广谱抗哺乳类动物PrP单克隆抗体(monoclonal antibody, McAb), 用牛朊蛋白(prion protein, PrP)多肽(209~228 aa)与匙孔槭血蓝蛋白(keyhole limpet hemocyanin, KLH)偶联物免疫Balb/C小鼠. 经细胞融合和克隆后获得针对上述多肽的杂交瘤细胞株. 分别用Western blot和免疫组化(immunohistochemistry, IHC)的方法检测这些McAbs与重组人(human, Hu)、牛(bovine, Bo)、仓鼠(hamster, Ha)PrP蛋白、牛脑组织中的正常朊蛋白(cellular PrP, PrPc)和致病性朊蛋白(scrapie of prion, PrPSc)的反应性. 本文为制备高效价抗PrP McAb提供了一个简单、易行的方法. 制备的抗体可用于研究哺乳类PrP生物学特性, 检测可传播性海绵样脑病, 特别是对牛海绵样脑病的诊断具有重要意义.     

ESR Studies on Lipid-protein Interaction in Gluten

The interaction of protein with lipid in wheat gluten has been studied by electron spin resonance (ESR). The gluten in the flour suspension was spin-labeled with a fatty acid spin label (N-oxyl-4,4'-dimethyloxazolidine derivative of 5-ketostearic acid) and washed out from the flour. The ESR spectra of the spin label incorporated in gluten exhibited clearly separated parallel and perpendicular hyperfine splittings. The orientation of the gluten lipid and its fluidity showed temperature dependence. Phase transition was observed at 25°C. Compared with gluten, vesicles of the lipids extracted from flour were found to be in a less oriented, highly fluid state, and with much lower activation energy for rotational viscosity, while the reconstituted gluten, which was prepared by mixing purified gluten protein and the extracted lipids, had a lipid environment similar to that of gluten. The results indicate that the lipid was immobilized in the gluten matrix by strong interaction with protein.     

胶原、壳聚糖包覆的小单层脂质体的体外稳定性评价

为了提高小单层脂质体（ＳｍａｌＵｎｉｌａｍｅｌａｒＶｅｓｉｃｌｅｓ,ＳＵＶ）的体外稳定性,以５（６）－羧基荧光素（５（６）－ＣＦ）为荧光探针,研究了脂质体被胶原蛋白和壳聚糖这两种天然生物大分子包覆后的通透性。发现,胶原蛋白、壳聚糖和磷脂酰胆碱（ＰＣ）的重量比分别为２：１和８：１时,已能明显降低脂质体的通透性。并以一种分子内电荷转移化合物３－甲氧基－４＇－Ｎ,Ｎ－二甲氨基黄酮（ＤＭＭＦ）为探针,用荧光偏振法研究了胶原蛋白、壳聚糖和ＰＣ在上述比例下,对脂质体膜流动性的影响,发现脂质体在被包覆前后,其膜的流动性没有明显的改变。可见,胶原蛋白、壳聚糖包覆脂质体能够在基本不干扰脂质体膜流动性的情况下,明显地提高其体外的稳定性     

A Spin-Label Study on Lipids in Dough Formed at Various Concentrations of Oxygen

The effect of oxygen on wheat flour lipids during dough mixing was investigated by analysis of the lipid composition and by an ESR technique with a fatty acid spin-label (4,4’-dimethyl-oxazolidine-N-oxyl derivative of 5-ketostearic acid). Dough was prepared in the presence of the spin-label under an atmosphere of air, nitrogen, 95% nitrogen—5% oxygen or oxygen, and the gluten was obtained by washing out the starch. ESR spectra of the spin-label incorporated into the gluten showed decreases in the order parameter, rotational correlation time and activation energy for rotational viscosity with increasing atmospheric oxygen concentration. During dough mixing in oxygen, oxidation of lipids proceeded and bound lipids slightly decreased. These data indicate that modification of lipids by incorporated oxygen leads to an increase in their fluidity and to a decrease in their hydrophobic interaction with protein in dough.     

The stability and functional properties of proteoliposomes mixed with dextran derivatives bearing hydrophobic anchor groups.

Liposomes composed of Escherichia coli phospholipid were coated with polysaccharides bearing hydrophobic palmitoyl anchors. The effect on the stability of liposomes without or with integral membrane proteins was investigated. A high concentration of hydrophobized dextrans protected the liposomes against detergent degradation, decreased the fluidity of the membranes, prevented fusion of the liposomes and enhanced their stability. Proteoliposomes containing beef heart cytochrome-c oxidase and the lactose transport carrier of E. coli were similarly affected by coating with the dextrans. Under these conditions both membrane proteins were still active. Long-term stability of the coated liposomes was obtained only in the absence of the integral membrane proteins.     

Physicochemical properties of proteins from wheat grown under high-contrast climatic conditions

Studies using electrophoresis, gel chromatography, viscometry, and calorimetry revealed an interrelation of several physicochemical properties of proteins of soft wheat grown under conditions of cool and wet weather with rheological characteristics of gluten and dough and bread quality. The ratio of gliadin and albumin-globulin polypeptides in flour with short-tearing gluten was much lower compared to that in flour with normal gluten. Proteins from flour with short-tearing gluten, including the water-soluble and salt-soluble fraction, had a loose spatial structure. Gluten fractions of this gluten (gliadin and glutenin) were characterized by a more compact and elongated structure compared to normal gluten. As distinct from normal gluten, the conformation of protein particles in short-tearing gluten depended little on hydrophobic interactions. The results suggest that the main components of grain determine the rheological properties of short-tearing gluten.     

Physicochemical properties of proteins from wheat grown under high-contrast climatic conditions

Studies using electrophoresis, gel chromatography, viscometry, and calorimetry revealed an interrelation of several physicochemical properties of proteins of soft wheat grown under conditions of cool and wet weather with rheological characteristics of gluten and dough and bread quality. The ratio of gliadin and albumin-globulin polypeptides in flour with short-tearing gluten was much lower compared to that in flour with normal gluten. Proteins from flour with short-tearing gluten, including the water-soluble and salt-soluble fraction, had a loose spatial structure. Gluten fractions of this gluten (gliadin and glutenin) were characterized by a more compact and elongated structure compared to normal gluten. As distinct from normal gluten, the conformation of protein particles in short-tearing gluten depended little on hydrophobic interactions. The results suggest that the main components of grain determine the rheological properties of short-tearing gluten.     

Isolation of a Spore Germination Inhibitor from a Cellular Slime Mold Dictyostelium discoideum

The functional properties of gluten obtained by treating with chymotrypsin at alkali pH were investigated. The gluten was treated by chymotrypsin at pH 10.0 and 20°C, and was found to be deamidated to a state that was scarcely subject to proteolysis by chymotrypsin. The degree of deamidation of the gluten reached about 25% by this treatment for 2 hr. The functional properties of the gluten thus obtained were investigated in regard to deamidation. The enzymatically deamidated gluten greatly improved such functional properties as solubility and emulsifying ability. In particular, the solubility of the treated gluten was remarkably high in the pH range of 5 to 8, in which native gluten is insoluble. It was apparent that the improvement in functional properties of gluten was mainly due to the deamidation induced by treating with chymotrypsin at pH 10.0 and 20°C.     

Conformation and Surface Properties of Deamidated Gluten

The surface properties of deamidated gluten were investigated with respect to their conformational changes. The helix content of gluten decreased curvilinearly with its decrease of deamidation. The surface tension decreased in proportion to the degree of deamidation. On the other hand, the surface hydrophobicity of gluten increased remarkably in proportion to the degree of deamidation. The emulsifying properties of gluten were improved greatly by deamidation, correlating linearly with the surface hydrophobicity. From these results, the relationships between the conformational changes and functional properties of deamidated gluten are discussed.     

Acid Hydrolysis of Wheat Gluten Induces Formation of New Epitopes but Does Not Enhance Sensitizing Capacity by the Oral Route: A Study in “Gluten Free” Brown Norway Rats

Background

Acid hydrolyzed wheat proteins (HWPs) are used in the food and cosmetic industry as emulsifiers. Cases of severe food allergic reactions caused by HWPs have been reported. Recent data suggest that these reactions are caused by HWPs produced by acid hydrolysis.

Objectives

To examine the sensitizing capacity of gluten proteins per se when altered by acid or enzymatic hydrolysis relative to unmodified gluten in rats naïve to gluten.

Methods

High IgE-responder Brown Norway (BN) rats bred on a gluten-free diet were sensitized without the use of adjuvant to three different gluten products (unmodified, acid hydrolyzed and enzymatic hydrolyzed). Rats were sensitized by intraperitoneal (i.p.) immunization three times with 200 µg gluten protein/rat or by oral dosing for 35 days with 0.2, 2 or 20 mg gluten protein/rat/day. Sera were analyzed for specific IgG and IgE and IgG-binding capacity by ELISA. IgE functionality was measured by rat basophilic leukemia (RBL) assay.

Results

Regardless of the route of dosing, all products had sensitizing capacity. When sensitized i.p., all three gluten products induced a strong IgG1 response in all animals. Acid hydrolyzed gluten induced the highest level of specific IgE but with a low functionality. Orally all three gluten products induced specific IgG1 and IgE but with different dose-response relations. Sensitizing rats i.p. or orally with unmodified or enzymatic hydrolyzed gluten induced specific IgG1 responses with similar binding capacity which was different from that of acid hydrolyzed gluten indicating that acid hydrolysis of gluten proteins induces formation of ‘new’ epitopes.

Conclusions

In rats not tolerant to gluten acid hydrolysis of gluten enhances the sensitizing capacity by the i.p. but not by the oral route. In addition, acid hydrolysis induces formation of new epitopes. This is in contrast to the enzymatic hydrolyzed gluten having an epitope pattern similar to unmodified gluten.     

Rapid isolation of gluten-digesting bacteria from human stool and saliva by using gliadin-containing plates

The number of individuals with gluten intolerance has increased dramatically over the last years. To date, the only therapy for gluten intolerance is the complete avoidance of dietary gluten. To sustain a strictly gluten-free diet, however, is very challenging. Therefore, there is need for a non-dietary therapy. Any such treatment must appreciate that the immunogenic part of gluten are gliadin peptides which are poorly degraded by the enzymes of the gastrointestinal tract. Probiotic therapy and oral enzyme therapy containing gluten-degrading bacteria (GDB) and their gliadin-digesting enzymes are possible new approaches for the treatment of gluten intolerance, however effectively isolating GDB for these treatments is problematic. The goal of this study was to develop an easy technique to isolate GDB rapidly and efficiently with the hope it might lead to newer ways of developing either probiotics or traditional medicines to treat gluten intolerance. Several researchers have already isolated successfully GDB by using gluten minimal or limited agar plates. Although these plates can be used to isolate bacteria which can tolerate gluten, further assays are needed to investigate if the same bacteria can also digest gluten. The agar plates we developed can detect bacteria which cannot only tolerate gluten but are able to digest it as well. Therefore, we were able to combine two steps into one step. Using such technologies, we were able to isolate five GDB from saliva and stool, and identified three bacterial reference strains with gluten-degrading activity. The technique we developed to isolate bacteria with gluten-degrading activity is fast, effective, and easy to use. The GDB isolated by our technology could have potential as part of a probiotic or enzymatic therapy for people with gluten intolerance.