Large-scale purification of hepatitis B surface antigen using affinity chromatography

Summary Large-scale purification of hepatitis B surface antigen, applicable to the preparation of potential vaccines for prevention of hepatitis B, is described. The method involves the following steps: precipitation of serum with polyethylene glycol 6000, affinity chromatography on concanavalin A-Sepharose and on -aminononyl-Sepharose, and isopycnic centrifugation.This study was supported by grant 09011 from the National Heart, Lung and Blood Institute. We thank Dr. B. Hollinger for testing HB_sAg samples by a complement fixation test.     

Biochemistry: a cadmium enzyme from a marine diatom

The ocean biota contains a vast reservoir of genomic diversity. Here we present the sequence and preliminary characterization of a protein that is a cadmium-containing carbonic anhydrase from the marine diatom Thalassiosira weissflogii. The existence of a cadmium enzyme in marine phytoplankton may indicate that there is a unique selection pressure for metalloenzymes in the marine environment, and our discovery provides a long-awaited explanation for the nutrient-like behaviour of cadmium in the oceans.     

阿尔茨海默症新药T-588的合成

阿尔茨海默症是一类神经退行性疾病 ,其症状主要表现为病人记忆和认知能力不同程度的丧失 ,行为活动发生障碍。经研究发现 ,此病患者脑细胞产生的神经递质有许多缺损。其中乙酰胆碱能 (Ａｃｈ)系统神经递质缺损非常明显 ,这一发现激起了一系列提高脑部 (Ａｃｈ)水平药物的研究[1] 。Ｔ - 5 88化学名为Ｒ(- ) - 1- (5-苯并噻吩 ) - 2 - [2 - (Ｎ ,Ｎ -二乙胺基 )乙氧基 ]乙醇盐酸盐 ,即为一种促进脑神经中 (Ａｃｈ)释放的类胆碱类新药。此药目前在日本处于临床研究阶段 ,且临床表现良好[2 ] 。本文将详细报导Ｔ - 5 88的合成方法。Ｔ - 5 88…     

我国硒资源变硒产业的重点、难点和发展实践

从整体来看我国硒资源较为匮乏,约有 72% 的地区属于缺硒地区,同时我国存在256个富硒地区。部分富硒地区立足自身硒资源优势,大力发展硒产业,实现了硒资源向硒产业的转化,但仍面临一些问题和挑战。本研究从硒产业发展的标准化、智慧化、绿色化、品牌化4个方面系统地梳理了我国硒产业发展存在的难点问题,指出我国硒产业发展的重点方向,介绍了我国富硒地区硒产业发展实践,最后从加强标准化、智慧化、绿色化及品牌化等“四化”的建设角度,为我国硒资源更好地变为硒产业,提供了有关综合解决方案的系统性思考。     

Cloning and expression of a functional serotonin transporter from rat brain

Selective antagonism of serotonin (5-hydroxytryptamine, 5HT) and noradrenaline transport by antidepressants is a key element in the 'amine' hypothesis of affective disorders. Uptake and/or transport sites of 5HT have been reported to be reduced in platelets of patients suffering from depression and in post-mortem brain samples of depressed patients and suicide victims. To date there has been little molecular information available on the structure and regulation of 5HT transporters. Using the polymerase chain reaction with degenerate oligonucleotides derived from two highly conserved regions of the transporters for noradrenaline and gamma-aminobutyric acid (GABA), we have identified a large family of related gene products expressed in rodent brain. One of these products hybridizes to a single 3.7-kilobase RNA restricted to rat midbrain and brainstem, where it is highly enriched within the serotonergic raphe complex. Transfection with a single 2.3-kilobase brainstem complementary DNA clone is sufficient to confer expression of a Na(+)-dependent 5HT transporter upon nonneural cells, with transport selectively and potently antagonized by 5HT uptake-specific antidepressants, including paroxetine, citalopram and fluoxetine.     

Defective acidification of intracellular organelles in cystic fibrosis.

The phenotype of cystic fibrosis (CF) includes abnormalities in transepithelial transport of Cl- (refs 1-5), decreased sialylation and increased sulphation and fucosylation of glycoproteins, and lung colonization with Pseudomonas. It is not apparent how these abnormalities are interrelated, nor how they result from loss of function of the CF gene-encoded transmembrane regulator (CFTR). We have previously shown that that the pH of a secretory granule is regulated by the vesicular conductance for Cl- (ref. 11). Here we find defective acidification in CF cells of the trans-Golgi/trans-Golgi network, of prelysosomes and of endosomes as a result of diminished Cl- conductance. Sialytation of proteins and lipids is reduced and ligand traffic altered. These abnormalities can result from defective acidification because vacuolar pH regulates glycoprotein processing and ligand transport. The CF phenotype is similar to that of alkalinized cells and acidification-defective mutatants.