板栗氮素营养与花性的表现

在板栗不同物候期间对其叶片,芽和枝皮中的蛋白态氮,非蛋白态氮和蛋白质氨基酸等进行测定,结果表明：能分化雌花的芽比只能分化雄花的芽含较多的非蛋白态氮和蛋白态氮,不同性别表现的新梢叶片非蛋白态氮含量及利用的时机不同,结果母枝上雌性表现区段枝皮比只有雄性表现区段枝皮中含较多的非蛋白态氮,氮素营养中以非蛋白态氮与雌性表现关系密切,花芽与叶芽中组成蛋白质的氨基酸种类没有差别,即花性表现与所测的１７种蛋白质氨     

Freezing resistance in some Antarctic fishes

Measurements of serum freezing points in three Antarctic marine fishes indicated that they do not freeze in the -1.87 degrees C seawater because their blood is isosmotic to seawater. Concentrations of sodium chloride, urea, and free amino acids in the serum accounted for only half of the freezing-point depression of the serum. A protein containing carbohydrate was isolated which accounted for 30 percent of the freezing-point depression of the serum.     

大气苯酚在蓖麻蚕生态系统中的积累和迁移

定量调查了间歇性大气苯酚在蓖麻蚕生态系统中的积累和迁移。大气苯酚通过气孔被蓖麻植物和蓖麻蚕吸收并积累 ,蓖麻植物又通过蓖麻叶把苯酚带入蚕体 ,也会带入蓖麻籽 ,并且通过植株残体把苯酚迁入土壤和水分。苯酚进入蚕体后 ,除积累在蚕体组织外 ,还通过蚕丝和蚕粪排出体外。蚕粪作为肥料 ,内含的苯酚通过植物进入下一轮循环 ;蚕粪作为动物饲料 ,则影响鱼和鸡等动物生产。污染蓖麻叶中的苯酚一部分进入蚕体组织 ,并在其中积累 ,但大部分通过粪便排出体外。大气中的苯酚直接进入蚕体后 ,很少通过粪便排出体外 ,而主要在血液等组织中积累 ,在丝腺中的积累也大大超过污染饲料的影响     

Immunoglobulin structure: variation in amino acid sequence and length of human lambda light chains

Variation and conservation in the primary structure of human lambda light chains is revealed by complete amino acid sequence of three Bence Jones proteins. These proteins differ in amino acid sequence in from 38 to 48 positions; they are of unequal length in the amino-terminal half of the chain but have identical sequence in the last 105 amino acids.     

肽在动物生产上的应用

蛋白质的营养问题一直是营养学中的一个重要课题，但其传统的营养代谢观点认为必须分解为氨基酸才能被小肠吸收。近年来研究人员所揭示的有关蛋白质和氨基酸消化代谢的情况，被消化的蛋白质大部分是以低聚肽而不是以单体氨基酸被吸收，而且进入血液循环中的小肽能直接参与组织蛋白质的合成，所以小肽的营养作用逐步被人们所认识，特别是对动物消化代谢的影响。     

Angiogenic factors

Within the past 2 years, several angiogenic factors have been fully purified, their amino acid sequences determined, and their genes cloned. These polypeptides include acidic and basic fibroblast growth factor, angiogenin, and transforming growth factors alpha and beta. Other less well characterized angiogenesis factors have also been isolated, some of which are lipids. This article traces the discovery of the angiogenic factors and describes their possible significance in understanding growth regulation of the vascular system. When evaluated according to their putative targets, they appear to fall into two groups: those that act directly on vascular endothelial cells to stimulate locomotion or mitosis, and those that act indirectly by mobilizing host cells (for example, macrophages) to release endothelial growth factors. In addition to their presence in tumors undergoing neovascularization, the same angiogenic peptides are found in many normal tissues where neovascularization is not occurring. This suggests that physiological expression of angiogenic factors is tightly regulated. In addition to the persistent angiogenesis induced by tumors, it now appears that a variety of nonneoplastic diseases, previously thought to be unrelated, can be considered as "angiogenic diseases" because they are dominated by the pathologic growth of capillary blood vessels.     

An expanded eukaryotic genetic code

We describe a general and rapid route for the addition of unnatural amino acids to the genetic code of Saccharomyces cerevisiae. Five amino acids have been incorporated into proteins efficiently and with high fidelity in response to the nonsense codon TAG. The side chains of these amino acids contain a keto group, which can be uniquely modified in vitro and in vivo with a wide range of chemical probes and reagents; a heavy atom-containing amino acid for structural studies; and photocrosslinkers for cellular studies of protein interactions. This methodology not only removes the constraints imposed by the genetic code on our ability to manipulate protein structure and function in yeast, it provides a gateway to the systematic expansion of the genetic codes of multicellular eukaryotes.     

An alternative bactericidal mechanism of action for lantibiotic peptides that target lipid II

Lantibiotics are polycyclic peptides containing unusual amino acids, which have binding specificity for bacterial cells, targeting the bacterial cell wall component lipid II to form pores and thereby lyse the cells. Yet several members of these lipid II-targeted lantibiotics are too short to be able to span the lipid bilayer and cannot form pores, but somehow they maintain their antibacterial efficacy. We describe an alternative mechanism by which members of the lantibiotic family kill Gram-positive bacteria by removing lipid II from the cell division site (or septum) and thus block cell wall synthesis.     

Organic Substance Metabolism in Seeds of Sophora japonica during Germination

The metabolism of fats,proteins and carbohydrates and the change of enzyme activity in seeds of Sophora japonica during germination were studied by methods of Soxhlet‘s extraction,flow injection and colorimetric analysis of spectrophotometer for provding theoretical basis for germination and storage of seeds of forest trees.The results are as follows:(1) The activity of enzymes in the seeds does not always coincide with the increase or decrease of their corresponding substances during germination of the seeds of Sophora japonica.(2) Proteins were first utilized during germination of the seeds;(3)The fatty acids reducing sugar and amino acids in the radiele plumular axis were used psecedently over all others when the embryos grew.(4) excessive small-molecular substances produced by hydrolysis would accumulate in tissres and sometimes they were stored temporarily in the form of storage substances and finally uscd for embryo growth.     

Diversity considerations in HIV-1 vaccine selection

Globally, human immunodeficiency virus-type 1 (HIV-1) is extraordinarily variable, and this diversity poses a major obstacle to AIDS vaccine development. Currently, candidate vaccines are derived from isolates, with the hope that they will be sufficiently cross-reactive to protect against circulating viruses. This may be overly optimistic, however, given that HIV-1 envelope proteins can differ in more than 30% of their amino acids. To contend with the diversity, country-specific vaccines are being considered, but evolutionary relationships may be more useful than regional considerations. Consensus or ancestor sequences could be used in vaccine design to minimize the genetic differences between vaccine strains and contemporary isolates, effectively reducing the extent of diversity by half.     

芦笋茎不同部位氨基酸含量的分析测定

[目的]测定分析芦笋茎不同部位中氨基酸含量,为芦笋营养价值的开发利用提供理论依据。[方法]利用氨基酸分析仪对芦笋茎不同部位氨基酸含量及组成进行测定和分析。[结果]18种氨基酸在不同部位均有检出,嫩尖中氨基酸总量、人体必需氨基酸含量、儿童必需氨基酸含量最高;嫩茎中鲜味氨基酸含量、支/芳比最高。[结论]芦笋茎不同部位具有不同的营养价值和药用价值,这为芦笋的开发利用提供了理论依据。     

多肽和蛋白质的人工合成评述

多肽和蛋白质的人工合成,就是多个氨基酸在一定的条件下通过肽键形成多肽链。氨基酸是合成多肽和蛋白质的原料。在合成前各个氨基酸都必须经过基团保护、氨基和羧基的活化处理,然后经接肽,去除保护基,最后形成多肽链。本文对目前国内外常用的液相合成法和固相合成法的原理和步骤进行了简要的评述。     

烟台沿海4种常见海藻的氨基酸分析及营养评价

用高效液相色谱仪测定了烟台沿海4种常见海藻中各种氨基酸的组成,并对其进行营养评价。结果表明:4种海藻样品经酸水解处理,均含有16种氨基酸,包括7种人类必需的氨基酸,2种半必需氨基酸和其他7种非必需氨基酸;各种必需氨基酸的配比合理,除叉枝藻外,其他3种海藻的E/N和E/T值与WHO/FAO提出的E/N约为60%、E/T约为40%的蛋白质参考模式相接近;萱藻和叉枝藻总氨基酸含量比较高,分别为11.30%和10.32%;此外,4种海藻中普遍含有多种药效氨基酸。说明4种海藻具有丰富的营养价值和良好的药用价值,值得大力开发利用。     

前列腺干细胞研究进展

干细胞是一种具有自我复制能力的多潜能细胞,具备多向分化潜能、自我更新、高度增殖的特性,具备再生各类人体器官以及人体的潜在能力,被医学界戏称为“全能细胞”。目前逐渐发现它在许多疾病的发生和治疗中发挥重大作用。近年研究发现前列腺内一样地存在着前列腺干细胞,在特定的环境中可以分化发育为前列腺组织,并与前列腺某些疾病有关。本文就有关前列腺干细胞相关文献研究进行综述。     

探索英语谚语在农民工英语培训中的运用

有越来越多的农民工自觉地参加到英语培训队伍中来。农民工由于年纪大导致记忆 力不佳,学习时间又相对较少,对要记忆的内容特感困难。若在农民工英语培训中适时穿插英 语谚语,不仅有利于他们学习英语,提高英语实际运用能力,还能帮助他们了解英语国家文化, 提高思想道德修养。英语谚语教学应注意教育性、适切性、灵活性、创造性等原则。     

Identification and Bioinformatics Analysis of SnRK2 and CIPK Family Genes in Sorghum

Through bioinformatic data mining, 10 SnRK2 and 31 CIPK genes were identified from sorghum genome. They are unevenly distributed in the sorghum chromosomes. Most SnRK2 genes have 8 introns, while the CIPK genes have a few （no intron or less than 3 introns） or more than I0 introns. Phylogenetic analysis revealed that SnRK2 genes belong to one cluster and CIPK genes form the other independent cluster. The sorghum SnRK2s are subgrouped into three parts, and CIPK into five parts. More than half SnRK2 and CIPK genes present in homologous pairs, suggesting gene duplication may be due to the amplification of SnRK family genes. The kinase domains of SnRK2 family are highly conserved with 88.40% identity, but those of the CIPK family are less conserved with 63.72% identity. And the identity of sorghum CBLinteracting NAF domains of CIPKs is 61.66%. What＇s more, regarding to the sorghum SnRK2 and CIPK kinases, they are characterized with distinct motifs and their subcellular localization is not necessarily the same, which suggests they may be divergent in functions. Due to less conserved sequences, complex subcellular localization, and more family members, sorghum CIPK genes may play more flexible and multiple biological functions. According to the phylogenetic analysis of SnRK genes and SnRK functional studies in other plants, it is speculated that sorghum SnRK2 and CIPK genes may play important roles in stress response, growth and development.     

Droplet countercurrent chromatography

A new form of countercurrent chromatography, named droplet counter-current chromatography, has been developed. This all-liquid separation technique is based on the partitioning of solute between a steady stream of droplets of moving phase and a column of surrounding stationary liquid phase. Milligram quantities of dinitrophenyl (DNP) amino acids were separated with an efficiency comparable to that of gas chromatography.     

绵羊TTF-1基因分子克隆及序列分析

以经产小尾寒羊母羊基因组DNA为模板,利用特异性引物对P1和P2对绵羊甲状腺转录因子-1(TTF-1)基因进行扩增,克隆入pGEM-T载体.转化后挑取阳性克隆进行酶切与测序鉴定,并对获得的TTF-1基因序列及推导的氨基酸序列进行生物信息学分析.结果表明,扩增的绵羊TTF-1基因序列长度为1 459 bp,包括部分外显子1、外显子2序列以及内含子,共编码174个氨基酸.该基因与GeneBank报道牛、狗、猪、人、和小鼠的基因序列同源性分别为98.7%、98.3%、97.5%、96.6%和96.6%.内含子与猪、人、鼠的内含子同源性为83.7%、74.9%和59.5%.     

Biosynthesis and secretion of proatrial natriuretic factor by cultured rat cardiocytes

Rat atrial natriuretic factor (ANF) is translated as a 152-amino acid precursor preproANF. PreproANF is converted to the 126-amino acid proANF, the storage form of ANF in the atria. ANF isolated from the blood is approximately 25 amino acids long. It is demonstrated here that rat cardiocytes in culture store and secrete proANF. Incubation of proANF with serum produced a smaller ANF peptide. PreproANF seems to be processed to proANF in the atria, and proANF appears to be released into the blood, where it is converted by a protease to a smaller peptide.     

论中国古典园林设计中的曲线意识及其形成

曲线作为一种几何形态，存在于客观世界的万事万物中，尤其对以视觉感知为主的造型艺术，曲线更是一种必不可少的造型元素，其使用顺手可拈。在园林设计中，尤其相对中国古典风景园林而言，大量运用的曲线更使其意境幽远，妙趣横生。因此，从园林设计中的曲线形式开始，逐步展开对园林设计中曲线审美意识及其形成相关因素的探讨，以及进一步对中国古典造园思想与手法的深层研究，对当代园林设计有重要意义。