Human lipoprotein lipase complementary DNA sequence

Lipoprotein lipase is a key enzyme of lipid metabolism that acts to hydrolyze triglycerides, providing free fatty acids for cells and affecting the maturation of circulating lipoproteins. It has been proposed that the enzyme plays a role in the development of obesity and atherosclerosis. The human enzyme has been difficult to purify and its protein sequence was heretofore undetermined. A complementary DNA for human lipoprotein lipase that codes for a mature protein of 448 amino acids has now been cloned and sequenced. Analysis of the sequence indicates that human lipoprotein lipase, hepatic lipase, and pancreatic lipase are members of a gene family. Two distinct species of lipoprotein lipase messenger RNA that arise from alternative sites of 3'-terminal polyadenylation were detected in several different tissues.     

Morphine in cow and human milk: could dietary morphine constitute a ligand for specific morphine (mu) receptors?

Morphine has been found in cow and human milk at concentrations of 200 to 500 nanograms per liter. Multistep purification yields a material that has immunological, biological, pharmacological, and chemical properties identical to those of morphine. Similar morphine-like material, which has been tentatively identified in some common plant sources, may be a ubiquitous dietary constituent and a possible source for the material in milk. Since morphine (mu) receptors have a low affinity for enkephalins, and since morphine-like materials have been described in brain and intestine, it is possible that morphine in food may be the source of this material and a normal ligand specific for mu receptors.     

Space, stars, c60, and soot

Although carbon has been subjected to far more study than all other elements put together, the buckminsterfullerene hollow-cage structure, recently proposed to account for the exceptional stability of the C(60) cluster, has shed a totally new and revealing light on several important aspects of carbon's chemical and physical properties that were quite unsuspected and others that were not previously well understood. Most significant is the discovery that C(60) appears to form spontaneously, and this has particularly important implications for particle formation in combustion and in space as well as for the chemistry of polyaromatic compounds. The intriguing revelation that 12 pentagonal "defects" convert a planar hexagonal array of any size into a quasi-icosahedral cage explains why some intrinsically planar materials form quasi-crystalline particles, as appears to occur in the case of soot. Although the novel structural proposal has still to be unequivocally confirmed, this article pays particular attention to the way in which it provides convincing explanations of puzzling observations in several fields, so lending credence to the structure proposed for C(60).     

中国转基因植物产业化的研究进展及存在问题

综合分析了全球与中国转基因植物的产业化现状,结果表明中国转基因植物产业化已取得重大成果，在某些作物上已达到国际先进水平,转基因作物的种植面积居全球第5位。但总体看尚处于发展阶段，与发达国家相比还有一定差距。本文分析了中国转基因植物研究中存在的不足及其产业化进程滞后的原因，并对中国今后的转基因植物产业化发展提出了建议。     

草鱼出血病病毒减毒的研究

草鱼出血病病毒ＧＣＨＶ－８２９野毒株在ＰＳＦ细胞连续传代过程,于培养液中加入一定浓度的桉液,传至１９代已达减毒目的,继续传至２９代其减毒效果保持稳定,２７代后不再加入桉液,继续传至３７代其减毒效果仍然保持稳定不变。致弱病毒对草鱼的安全性好,免疫原性强,用该弱毒株制备的弱毒疫苗免疫草鱼后,草鱼的成活率和免疫保护率均达１００％,表明桉液的草鱼出血病病毒的一种良好减毒剂,经桉液减毒的ＧＣＨＡＶ－８９２是     

Three-dimensional structure of interleukin-2

Interleukin-2 is an effector protein that participates in modulating the immune response; it has become a focal point for the study of lymphokine structure and function. The three-dimensional structure of the interleukin molecule has been solved to 3.0 angstrom resolution. Interleukin-2 has a novel alpha-helical tertiary structure that suggests one portion of the molecule forms a structural scaffold, which underlies the receptor binding facets of the molecule.     

Air pollution. Panel backs EPA and 'six cities' study

The Environmental Protection Agency (EPA) has won a major victory in the fierce battle over its tough new standard for particulate air pollution. Dealing a sharp blow to critics from industry, a nonpartisan research group has reevaluated key data that EPA relied upon to set that standard and has come out firmly behind the agency.     

行标实施,缓控释肥迎来第一春

<正>没有标准和规则,一个新产品或新行业的发展是不可能真正实现规范化和产业化的。说到标准,业内人士也许还记得,因为没有标准,复合     

Indirect observation by 13C NMR spectroscopy of a novel CO2 fixation pathway in methanogens

High-field carbon-13 nuclear magnetic resonance (NMR) spectroscopy has been used to monitor the isotopic dilution of doubly carbon-13-labeled precursors for 2,3-cyclopyrophosphoglycerate, a novel primary metabolite that occurs in certain methanogens. A unique carbon dioxide fixation pathway that gives rise to asymmetric labeling of acetyl coenzyme A has been demonstrated in Methanobacterium thermoautotrophicum. The effect of selected metabolic inhibitors on the labeled species in the pathway has been examined by NMR. These techniques establish a general, sensitive method for the delineation of convergent biosynthetic pathways.     

草鱼出血病病毒减毒的研究

草鱼出血病病毒ＧＣＨＶ－８２９野毒株在ＰＳＦ细胞连续传代过程,于培养液中加入一定浓度的桉液,传至１９代已达减毒目的,继续传至２９代其减毒效果保持稳定,２７代后不再加入桉液,继续传至３７代其减毒效果仍然保持稳定不变。致弱病毒对草鱼的安全性好,免疫原性强,用该弱毒株制备的弱毒疫苗免疫草鱼后,草鱼的成活率和免疫保护率均达１００％,表明桉液的草鱼出血病病毒的一种良好减毒剂,经桉液减毒的ＧＣＨＡＶ－８９２是     

Science in europe/the antinuclear movement takes hold

Five months after the announcement of President Carter's nonproliferation policy, the common wisdom in this country is that Europe has hardly wavered in its rush toward nuclear power. The cry that "Europe will do what it wants whether the United States builds a breeder or not" is often heard from American nuclear interests, with apparent justification as the State Department has shown little visible progress in negotiating new agreements and some signs of retreating from its original goals. But popular protest against nuclear power has reached a pitch in Europe that would be barely imaginable today in this country, and the political strength of the antinuclear forces has become formidable, not only in Sweden where nuclear power was a pivotal issue last year, but across the continent. West Germany's research minister recently predicted that that country's two ruling coalition parties will vote for a complete moratorium on nuclear construction when they meet this fall, and some observers predict that any moratorium contingent on creation of a waste disposal site could last up to 12 years. Beyond public opposition, the plutonium breeder is running into trouble in Germany for many of the same reasons it has in the United States; program delays, safety concerns, and cost overruns threaten to undermine the claim that it can one day become an economically competitive energy source. Nuclear opposition is far from being a single-issue movement in Europe, as groups of many political persuasions embrace it for their own reasons. But as the following report by Nigel Hawkes details, the Carter administration policy is not the only thing holding back nuclear power in Europe.-W.D.M.     

落叶松和桦木木材切面的剖切方向对胶接性能的影响

研究了落叶松和桦木木材切面的剖切方向对胶接性能的影响，试验结果表明：落叶松径切板的干状压缩剪切强度比弦切板的大，而湿状压缩剪切强度径切板的比弦切板的要小；而对于桦木，径切板的干状压缩剪切强度比弦切板的小，而湿状压缩剪切强度径切板的比弦切板的要大。文中还分析了造成这些现象的原因，造成落叶松径切板的干状压缩剪切强度比弦切板大的原因主要是落叶松木材早晚材间的差异大，造成落叶松径切板的湿状压缩剪切强度比弦切板小的原因主要是落叶松早晚材的湿涨率不一样以及有纹孔的作用；造成桦木径切板的干状压缩剪切强度比弦切板小的主要原因是弦切面是横断木射线，因此，在弦面上留下射线管胞的孔隙，在胶接时胶粘剂渗入就形成了更多的胶钉，而在湿状时这种孔隙成为了水分的通道，因而使而桦木湿状压缩剪切强度径切板的比弦切板的要大。     

Building R & d policy from strength

Many proposals have been made for new initiatives in our nation's research and development system. But before rushing into untried approaches, we need to look to the foundations of the system that has worked so well for us in the past. We have a climate for venture capital that has never been better; the world's greatest research universities; an industrial base that is moving aggressively into high technology, spurred by competition; and a defense effort that can be a major asset to civiliarn R & D. We should build our future by understanding and using these existing strengths.     

江苏省1980-2000(三期)景观格局变化分析

在GIS技术和FRAGSTATS软件的支持下,针对江苏省1980、1995和2000年的遥感TM图像资料,对景观格局的变化进行了分析,得出了江苏省20年间的景观格局变化的基本状况。结果表明:耕地面积减少,建造用地面积增加;TL、NP等景观指数增加,LPI指数下降,说明斑块形式趋于复杂。景观的破碎度从0.0192上升到0.0201,景观格局不稳定性变大。景观多样性指数的结果显示,研究区域的景观多样性增强。景观格局变化与自然和人文因素有关,这些为区域可持续发展提供决策信息。     

金大米的知识产权问题分析及启示

世界知名的转基因作物、富含类胡萝卜素的金大米是由公共研究机构以人道主义为目的研发的,金大米的研发过程经历曲折,它在得到众多荣耀的同时,也引来诸多争议,知识产权问题就是其中一个重要方面。本文在介绍金大米技术探索之路的基础上,通过分析金大米的知识产权问题,揭示表面上看来非常严重的知识产权障碍其实却并非不可逾越,尤其在发展中国家,例如在中国现在就可能没有与金大米相关的任何专利存在。本文还探讨了在生物技术领域内逐渐兴起的反公共地悲剧问题。最后结合实际,总结了金大米的知识产权问题带给中国科技工作者的启示,包括应认真对待在科研工作中可能出现的知识产权障碍和应认清中国现在仍基本处于公共地悲剧阶段而非反公共地悲剧阶段等。     

Electrophoretic variation of galactose-1-phosphate uridyltransferase

A specific method for starch-gel electrophoresis of galactose-1-phosphate uridyltransferase has been developed. Electrophoresis of red-cell hemolyzate from normal subjects and subjects homozygous for the Duarte variant has shown that the Duarte variant has a slightly faster electrophoretic mobility than the normal enzyme under the various conditions used. Molecular-weight estimation on Sephadex G-200 indicates that this observed difference in electrophoreticmobility of the Duarte variant is not due to difference in molecular size. Both enzymes have a molecular weigh of approximately 85,000.     

对流—扩散型方程数值解的混合E—L方法

为解决对流—扩散型方程数值解中出现的数值耗散和数值弥散,本文通过质点导数概念,将物理方程分解为Euler形式下的对流型方程和Lagrange形式下的扩散型方程,采用特征线法和区域离散数值方法分别求解,二者合成即为对流一扩散运动的整体数值模拟过程。数值试验表明:对于大Pe数,在激波区或解梯度较大的区域,本方法的数值解仍能保持较高精度。为数值模拟大气污染、水资源污染过程、粘性流体的流动过程及其他类似问题提供了一个良好的数值模型。     

食用菌制种新型消毒剂的应用研究

食用菌制种新型消毒剂,经反复试验和生产验证,对食用菌的母种、原种菌丝抑制小,接种后萌动快,发菌迅速,成品率高。用此消毒剂并可在箱外接种,操作简便,减少了工作时间和成本。该消毒剂对工作人员无毒,无过敏反应,无刺激性。     

Mandel方差分析法在基因型X环境互作研究中的应用初探

本文系统地介绍了Mandel二因子互作方差分析法的原理与方法,并应用1990年西南玉米区域试验资料详细说明共分析、计算方法。得到了一个估计试验资料的理论方程,用其估计的理论值与实际资料的吻合程度极高,是一种值得在G×E互作分析中广泛采用的分析方法。     

一种做为遗传学教学的实验材料——卤虫

卤虫做为一种经济动物已广泛应用于水产养殖业中,但是做为一种遗传学教学的实验材料尚无人报道过。通过多次实验,本文作者提出了一种改进后的观察卤虫染色体形态和数目的实验方法。同时,作者还例举了各种事实表明卤虫是一种很好的遗传学教学的实验材料。