蓖麻毒素—A链结构功能研究进展

蓖麻毒素（ｒｉｃｉｎ）是一种核糖体失活蛋白,是构建免疫毒素的一个重要成分,本介绍近年来ｒｉｃｉｎ－Ａ链的理化性质和制备,结构功能关系及其Ｎ－苷酶作用机制方面的研究进展．     

尖吻蝮蛇毒内一种新的抗血小板凝集蛋白agkisacuta …

从皖南尖吻蝮蛇毒中经阴离子交换层析和凝胶过滤层析分离纯化离纯化得到抗血小板凝集蛋白ａｇｋｉｓａｃｕｔａｃｉｎ,纯化的ａｇｋｉｓａｃｕｔａｃｉｎ由分子量为１４ｋＤ和１５ｋＤ的２条肽链通过二硫键连接,能有效抑制ｒｉｓｔｏｃｅｔｉｎ诱导的血小板凝集（ＩＣ５０为１８．５ｍｇ／Ｌ）,能轻微抑制凝血酶诱导的血小板聚集（ＩＣ５０为１．２２ｇ／Ｌ）,但对ＡＤＰ、胶原诱导的血小板聚集无影响。ａｇｋｉｓａｃｕｔａｃｉ     

包有蓖麻毒蛋白的脂质体的制备,性质及毒性研究

以半乳糖神经酰胺（ｇａｌａｃｔｏｓｙｌｃｅｒａｍｉｄｅ,ＧＣ）为材料,采用冷冻干燥脱水再水化法（ＤＲＶ法）制成包裹有蓖麻毒蛋白的半乳糖神经酰胺脂质体（ｒｉｃｉｎＧＣＬｓ）并对其性质及体外细胞毒性和动物毒性做了研究,实验结果表明,ｒｉｃｉｎ－ＧＣＬｓ的最大包封率可达７４．１％,粒度分布主要在０．５～０．８μｍ之间,符合静脉注射液的标准,脂质体冻干粉在４℃储存近半年,粒度分布几乎没有变化,体外细胞毒性     

免疫毒素的纯化

本文采用Ultrogel AcA 34凝胶柱纯化单克隆抗体和蓖麻毒素的结合物。结合物与游离毒素的分离较Sephadex G150柱好。继而利用蓖麻毒素B链能与半乳糖基结合的特性,用酸化Sepharose 4B柱进一步纯化结合物;达到完全除去游离抗体,使免疫毒素对靶细胞的特异性毒性提高20倍。     

Cibacron Blue亲和层析及应用

以Ｆ３ＧＡ（Ｃｉｂａｃｒｏｎ ＢｌｕｅＦ３ＧＡ）为配基建立了一种可用于免疫毒素（ＩＴ）分离纯化的亲和层析方法,实验中用三种不同来源的核糖体灭活蛋白（ＲＩＰ）,即蓖麻毒素Ａ链（ＲＴＡ）,苦撤毒素（Ｍｏｍｏｒｄｉｎ,ＭＴ）和Ｓａｐｏｒｉｎ,以探讨ＲＩＰ与Ｆ３ＧＡ的相互作用。分析三种ＲＩＰ均能引起Ｆ３ＧＡ吸收光谱明显红移,提示ＲＩＰ均可与Ｆ３ＧＡ发生特异结合,将Ｆ３ＧＡ与Ｓｅｐｈａｄｅｘ交联可获得Ｂｌｕ     

能诱导MGC-803细胞凋亡的新免疫毒IgY-ricinA(英文)

研究证明：许多化学药物的治疗都是以诱导细胞凋亡的方式杀伤癌细胞的。有关细胞凋亡的研究已成为肿瘤生物学研究中的一个新焦点。ＩｇＹｒｉｃｉｎＡ为本实验室新研制的一种免疫毒。与其它种类的免疫毒一样,它能够特异性地杀伤靶细胞。推测：免疫毒ＩｇＹｒｉｃｉｎＡ也是以诱导细胞凋亡的方式杀死癌细胞的。我们已经研究了免疫毒对靶细胞的杀伤能力和效果,本文则着重对细胞的杀伤机理进行探讨。本实验以胃癌细胞ＭＧＣ８０３为靶细胞,ＨｅＬａ细胞为非特异识别细胞,二倍体２ＢＳ细胞为正常对照细胞,进行ＩｇＹｒｉｃｉｎＡ处理,观察其诱导细胞凋亡的可能性。同时进行ＩｇＹ和ｒｉｃｉｎ处理,以期探明引起细胞凋亡的有效成分。ＯｌｙｍｐｕｓＢＸ荧光显微镜下观察到（Ｆｉｇ２,５＆６）：在细胞培养液中加入ＩｇＹｒｉｃｉｎＡ后,ＭＧＣ８０３细胞表现出典型的凋亡形态变化,即染色质浓缩、细胞皱缩并放出凋亡小体。细胞凋亡时ＤＮＡ被降解成寡核体长度的片段,在琼脂凝胶电泳上形成ＤＮＡ梯带,成为药物处理后确定细胞凋亡过程中细胞降解的一种生化指标。Ｆｉｇ３表明,用ＩｇＹｒｉｃｉｎＡ处理ＭＧＣ８０３细胞２４小时、用ｒｉｃｉｎ处理ＭＧＣ８０３和ＨｅＬａ     

蓖麻毒素A链的基因克隆

作为导向药物蓖麻毒素Ａ链在大肠杆菌中表达时不含糖基侧链,在体内半衰期长,可提高共作为导向药物的疗效。我们根据Ｒｉｃｉｎ基因核苷酸序列,设计Ｒｉｃｉｎ－Ａ的上,下游引物,通过ＰＣＲ（多聚酶链式反应）方法,扩增出Ｒｉｃｉｎ－Ａ链基因。与ｐＵＣ１９载体连接,转化到ＪＭ１０３大肠杆菌中,得到重组克隆。对其进行几种酶切鉴定,证明酶切位点正确,又经序列分析,读出与文献发表的Ｒｉｃｉｎ－Ａ序列只有两个碱基不同,     

Cibacron Blue亲和层析及应用

以Ｆ３ＧＡ（Ｃｉｂａｃｒｏｎ　Ｂｌｕｅ　Ｆ３ＧＡ）为配基建立了一种可用于免疫毒素（ＩＴ）分离纯化的亲和层析方法。实验中用三种不同来源的核糖体灭活蛋白（ＲＩＰ）,即蓖麻毒素Ａ链（ＲＴＡ）,苦瓜毒素（ｍｏｍｏｒｄｉｎ,ＭＴ）和Ｓａｐｏｒｉｎ,以探讨ＲＩＰ与Ｆ３ＧＡ的相互作用。分析显示三种ＲＩＰ均能引起Ｆ３ＧＡ吸收光诸明显红移,提示ＲＩＰ均可与Ｆ３ＧＡ发生特异结合。将Ｆ３ＧＡ与Ｓｅｐｈａｄｅｘ交联可获得Ｂｌｕｅｄｅｘ。Ｂｌｕｅｄｅｘ亲和层析是一种经济有效,简单易行,便于在各类实验室中使用的蛋白质亲和层析技术。结果表明：在低盐溶液中ＲＴＡ和ＭＴ均可迅速地与Ｂｌｕｅｄｅｘ结合,而在高盐溶液中（０．６５ｍｏｌ／ＬＮａＣｌ）又极易被洗脱回收。这一技术用于免疫毒素的研究可有效地去除游离抗体,而不影响其杀伤活性。     

稻纵卷叶螟对杂交水稻及常规水稻的生态反应

稻纵卷叶螟对杂交水稻及常规水稻的生态反应钱希（国营黄海农场,江苏省响水县２２４６２４）ＥｃｏｌｏｇｉｅａｌＲｅｓｐｏｎｓｅｓｏｆＲｉｃｅＣａｓｅｗｏｒｍｔｏＨｙｂｒｉｄＲｉｃｅｓａｎｄＴｒａｄｉｔｉｏｎａｌＲｉｃｅｓ￥ＱｉａｎＸｉ（ＴｈｅＳｔａｔｅＦａｒｍｏｆＹｅｌｌｏｗＳｅａ,ＸｉａｎｇｓｈｕｉＣｏｕｎｔｙ,Ｊｉａｎｇｓｕ,Ｐｒｏｖｉｎｃｅ２２４６２４）．ＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＥｃｏｌｏｇｙ,１９９３,１２（６）：２１－２４．Ｔｏｓｔｕｄｙｔｈｅｅｆｆｅｃｔｏｆｒｉｃｅｃｕｌｔｉｖａｒｓｏｎｔｈｅｏｖｉｐｏｓｉｔｉｏｎ,ｅｍｅｒｇｅｎｃｅ,ｗｏｒｍｄｅｖｅｌｏｐｍｅｎｔａｎｄｎａｔｕｒａｌｅｎｅｍｖｐａｒａｓｉｔｉｏｎｏｆｃａｓｅｗｏｒｍａｎｄｌｏｓｓｅｓｃａｕｓｅｄｂｙｔｈｅｐｅｓｔ,ｏｂｓｅｒｖａｔｉｏｎｓｈａｖｅｂｅｅｎｍａｄｅｏｎ１６ｒｉｃｅｃｕｌｔｉｖａｒｓｉｎＨｕａｎｇｈａｉＳｔａｔｅＦａｒｍｉｎＮｏｒｔｈｅｒｎＪｉａｎｇｓｕｐｒｏｖｉｎｃｅ,ｗｈｅｒｅｃａｓｅｗｏｒｍｇｒａｄｕａｌｌｙｂｅｃｏｍｅｍｏｒｅａｎｄｍｏｒｅｖｉ－ｏｌｅｎｔｓｉｎｃｅｔｈｅｃｈａｎｇｅｓｉｎｃｕｌｔｉｖａ     

一种纯化蓖麻毒素的新方法

该文介绍了一种新的提取、纯化蓖麻毒素的方法,首次将P-苯胺基-1-巯基-β-D-吡喃半乳糖苷（P—aminobenzyl-1-thoi-β-D-galactopyranoside）琼脂糖凝胶作为亲和层析介质,结合凝胶层析介质Sephcaryl S-200,通过两步层析纯化,获得了高纯度的蓖麻毒素。MALDI—TOF测得分子量为62925,LD50为12．4μg／kg。该方法可以制备高纯度蓖麻毒素。     

Investigation of the mechanism of temperature sensitivity of the electroreceptors of ampullae of lorenzini

In experiments on Black Sea skates (Raja clavata), the potential of the receptor epithelium of the ampullae of Lorenzini and spike activity of single nerve fibers connected to them were investigated during electrical and temperature stimulation. Usually the potential within the canal was between 0 and –2 mV, and the input resistance of the ampulla 250–400 k. Heating of the region of the receptor epithelium was accompanied by a negative wave of potential, an increase in input resistance, and inhibition of spike activity. With worsening of the animal's condition the transepithelial potential became positive (up to +10 mV) but the input resistance of the ampulla during stimulation with a positive current was nonlinear in some cases: a regenerative spike of positive polarity appeared in the channel. During heating, the spike response was sometimes reversed in sign. It is suggested that fluctuations of the transepithelial potential and spike responses to temperature stimulation reflect changes in the potential difference on the basal membrane of the receptor cells, which is described by a relationship of the Nernst's or Goldman's equation type.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov, Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Pacific Institute of Oceanology, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 67–74, January–February, 1980.     

Determination of stoichiometry of radioiodination of proteins

A sensitive method for the detection of small quantities of hydrophobic antioxidant free radical scavengers such as butylatedhydroxytoluene (BHT) and butylatedhydroxyanisole (BHA) in aqueous samples is described. The procedure involves extraction of the hydrophobic free radical scavenger into an organic solvent phase, followed by the subsequent reaction of an aliquot of this extract with the stable cation radical tris(p-bromophenyl)amminium hexachloroantimonate (TBACA). In experiments with BHT and BHA, the loss of TBACA absorbance at 730 nm was found to be linearly proportional to the amount of antioxidant added, with quantities of BHT as small as 200 pmol being easily detectable. In aqueous suspensions of dimyristoylphosphatidylcholine vesicles, assays of the aqueous BHT concentration showed that BHT partitioned strongly into the membrane phase, achieving very high BHT/phospholipid ratios. For a given concentration of BHT, partitioning into the membrane phase was greater in large, multilamellar liposomes than in either small, single-walled vesicles or in purified rat brain synaptic vesicle membranes. Direct assay of BHT and BHA in phospholipid membranes, however, was complicated by a nonspecific interaction between TBACA and the phospholipid.