组氨酸生产中间控制方法的研究

研究了组氨酸与Pauly试剂显色反应的适宜条件 ,并加入钠盐和酪氨酸对标准曲线进行校正后 ,作为组氨酸定量测定的工作曲线。该方法简便 ,快速 ,准确度高 ,重现性好     

植物叶片中过氧化氢含量测定方法的改进

Ti（Ⅳ）-H₂O₂比色法因背景物质干扰而测得的植物叶片内H₂O₂含量偏高，5％三氯乙酸抽提，活性炭脱色，Ti（Ⅳ）-4-(2-吡啶偶氮)间苯二酚(PAR)比色法测得的H₂O₂含量偏低.萃取法有效地脱去丙酮提液中的色素，且H₂O₂的回收率在95％以上.用过氧化氢酶(CAT）处理作空白对照，利用H₂O₂与Ti（Ⅳ）-PAR的显色反应，建立了一种简便、快速、准确的植物叶片内的H₂O₂含量测定方法，H₂O₂的最低检测浓度为0.25 μmol·L^－1.用该方法测得多种植物叶片中H₂O₂的含量在0.1～0.8 μmol·g^－1.     

An Improved Chemiluminescence Method for Hydrogen Peroxide Determination in Plant Tissues

As a consequence of the increasing importance of hydrogen peroxide in plant metabolism, more efficient methods are required for accurate determinations of its concentration in plant tissue and organs. Here we present a highly sensitive chemiluminescence (CL) method based on the Co (II) catalysed oxidation of luminol by H₂O₂. The replacement of ferricyanide, the traditional catalyst of luminol luminescence by Co (II), enhanced the sensitivity of the reaction towards H₂O₂ in three orders of magnitude. Thus, plant extracts can be diluted to such a level that quenching effects of phenols and ascorbic acid (ASA), which are normally present at high concentrations in plant tissues is avoided, and therefore, pre-treatments with PVP and ascorbate oxidase to remove these quenchers from plant-extracts become unnecessary. To exemplified the high performance of the method, measurements of H₂O₂ were carried out in PVP treated and non-treated extracts of grapevine leaf, a plant tissue that contain high levels of phenols and ASA. Moreover, increases in H₂O₂ levels were detected in disc-leaf treated with aminotriazole, a specific Cat inhibitor, showing the importance of Cat as a H₂O₂ scavenging enzyme in leaves of grapevine.     

An Improved Method for Standardization of Microspectrofluorometers

The use of meshed cadmium-zinc sulfide fluorescent particles in combination with an electron microscope locator grid greatly facilitates the standardization of miam spectrofluorometers. The fluorescent particles emit maximally at 570 nm, and the intensity of fluorescence is directly proportional to cross-sectional area when epi-illumination is used Details concerning technique and fluorescent particle characteristics are reported.     

An Improved Method for Estimating Macromolecular Synthesis

Estimating rates of DNA, RNA, and protein synthesis has beengreatly facilitated by the use of radioactive precursors. Currentlyavailable methods to assess macromolecular synthesis in higherplants are time-consuming and imprecise. In the procedure outlinedhere, the conventional method is simplified by processing thetissue intact. This method allows a rapid analysis and considerablyreduces the inherent variability associated with the conventionalmethod.     

一种改进的蛋白质超薄凝胶电泳方法

介绍了一种将聚丙烯酰胺凝胶固定在电泳夹板上的蛋白质电泳方法.通过此方法蛋白质电泳可以在0.4 mm厚的聚丙烯酰胺凝胶上进行.实验证明,经此方法处理的玻板结合凝胶非常牢固,在电泳后的所有处理步骤中都不会发生凝胶脱落现象.     

An Improved Method of Decalcification

Following several experimental investigations, an improved method of decalcification has been devised. The principle of this decalcification method is to obtain complete decalcification by a mixture of as high pH as possible without diminishing the stainability of the Nissl-granules (with Einarson's progressive staining method by means of gallocyanin). This is accomplished by the help of a buffer solution of equal parts of 8 N formic acid and 1 N sodium formate (pH 2.2). After-treatment consists only in rinsing in flowing water for 24 hours. Dehydration is in alcohol (70%, 96%, 100%); cedar oil; ligroin. Embedding in paraffin follows.     

An Improved Method for the Study of Chromosomes

It has been felt strongly that the current methods for the fixation of chromosomes are inadequate, inasmuch as the reagents are unduly long in reaching the important elements of the cells, particularly the nucleus. A realization of this situation has been at the bottom of the development of the so-called smear method. This method can, however, be advantageously employed only where loose cells are available, as in the reproductive elements of plants and animals. The present author has found that cutting up the material in very thin slices of almost microscopical tenuity, and passing them immediately into the best fixing solutions, namely those containing osmic acid, gives excellent results. The material is then assembled on cards in accordance with the present author's mass method (for which see the original article), and after embedding in nitrocellulose is sectioned 5μ or even thinner. Practically all methods of staining may be used, but the most satisfactory results have been achieved with Heidenhain's hematoxylin bleached almost to disappearance and followed by prolonged treatment with an aqueous safranin. This differentiates the chromosomal structures extremely well. It is clear by this method that chromosomes in all cases consist of a ground substance in which are situated two chromatids. In the somatic tissues these chromatids are apparently generally spiral and run in opposite directions. The crossing points of these spirals are responsible for the optical illusion which has been designated the gene.     

An Improved Method for the Synthesis of Flavanones

An isomerization of 2"-hydroxychalcones into the corresponding flavanones in ethanol in the presence of triethylamine is described.     

An Improved Method of Decalcification

Following several experimental investigations, an improved method of decalcification has been devised. The principle of this decalcification method is to obtain complete decalcification by a mixture of as high pH as possible without diminishing the stainability of the Nissl-granules (with Einarson's progressive staining method by means of gallocyanin). This is accomplished by the help of a buffer solution of equal parts of 8 N formic acid and 1 N sodium formate (pH 2.2). After-treatment consists only in rinsing in flowing water for 24 hours. Dehydration is in alcohol (70%, 96%, 100%); cedar oil; ligroin. Embedding in paraffin follows.     

An Improved Method for Marine Cyanobacterial DNA Isolation

Summary The method of Bolch, Blackburn, Jones, Orr & Grewe [Phycologia, 36, 6 11, 1997] developed for isolation of DNA from freshwater cyanobacteria was suitably modified to yield a simple, efficient and reproducible protocol for the isolation of DNA from different morphological types of marine cyanobacteria. This method resulted in a high yield of quality DNA suitable for polymerase chain reaction (PCR) amplifications.     

An Improved Method for Studying Grass Leaf Epidermis

Leaf epidermis of grasses is elaborate and important in the systematica of the Poaceae at subfamily and genus level. Most available techniques used in preparing leaf epidermis for microscopic studies are time-consuming and often produce preparations inadequate for studying histological detail. A combination of the hand scraping and maceration methods with modifications is proposed in this paper to prepare epidermal peels comparatively rapidly. One epidermal layer was scraped off and the mesophyll tissue removed from the epidermis to be studied by maceration in HNO, The recovered epidermal peel was neutralized in NaOH and stained with malachite green or safranin O. Preparations made by this technique are suitable for studies of epidermal features, measurements of special structures and determinations of trichome indices. This method has been used in a study investigating intraspecific variation in southern African pasture grasses.     

An Improved Method for Preparing Anti-B Lymphocyte Serum

THE preparation of a heterologous antiserum specific to the bursa equivalent (B) lymphoid cells of the mouse requires extensive absorption with mouse tissues, especially thymocytes, to obtain specificity. The cell surface antigen(s) against which the serum reacts has been termed mouse specific bone marrow derived lymphocyte antigen(s) (MBLA)¹. The specificity of anti-MBLA for the B lymphoid population has been demonstrated by cytotoxicity tests, by its ability to inhibit a portion of antigen binding cells and by adoptive immune responses of antiserum purified lymphoid cells (refs. 1 and 2 and unpublished results of E. Möller and myself).     

An Improved Pollen Grain Smear Method for Wheat

Anthers containing actively dividing pollen grains were treated 1 hour at 18-20° C. with 0.2% solution of colchicine, washed 1 hour in water, soaked in 0.002 M aqueous solution of 8-oxyquinoline at 10-14° C. for 1 hour, washed in water for 1 hour and then fixed in Carnoy's solution (alcohol, chloroform, acetic acid, 6:3:1) for 6 hours to overnight. They were washed successively in acetic-alcohol (1:1) 10-15 minutes, 70% alcohol 10-15 minutes and in water 30 minutes before hydrolysing them in bulk in 1 N HCl at 60° C. for 10-15 minutes. “Finally, they were stained in leuco-basic fuchsin for 15-30 minutes. Pollen grains were squeezed out of a stained anther in a small drop of egg albumen on a slide and the albumen smeared uniformly on the slide. The slide was dipped successively for a few seconds in glacial acetic acid and 45% acetic acid respectively. The smear was covered by a cover glass in a drop of aceto-carmine and pressed gently between folded filter papers. The cover glass was sealed with paraffin and stored overnight. To make the preparation permanent the paraffin was removed and the cover glass separated in a 1:1 mixture of acetic acid and n-butyl alcohol. The slide and the cover glass were then passed through n-butyl alcohol, 2 changes, and finally remounted in balsam.     

An Improved Method for Chromosome Counting in Maize

An improved method for counting chromosomes in maize (Zea mays L.) is presented. Application of cold treatment (5C, 24 hr), heat treatment (42 C, 5 min) and a second cold treatment (5C, 24 hr) to root tips before fixation increased the number of condensed and dispersed countable metaphase chromosome figures. Fixed root tips were prepared by the enzymatic maceration-air drying method and preparations were stained with acetic orcein. Under favorable conditions, one preparation with 50-100 countable chromosome figures could be obtained in diploid maize using this method. Conditions affecting the dispersion of the chromosomes are described. This technique is especially useful for determining the somatic chromosome number in triploid and tetraploid maize lines.     

一种改进的cDNA文库固相构建法

本文介绍一种新的cDNA文库固相构建法。文库构建过程中,cDNA的合成和修饰全部在固相介质――磁珠上完成,简便、迅速、文库质量高,能满足不同目的的cDNA文库构建,是一种值得借鉴和应用的好方法。 Abstract：A method for cDNA library construction was introduced.All enzymatic steps of library synthesis were performed on a solid support-magnetic beads.Therefore it combines fast speed and convenient with high quality library,making it ideally suited for most purposes.It is a good method and worth learning and utilization.     

An Improved Method for Identifying 8-O-Acetyl-N-Acetylneuraminic Acid

The periodic acid/thionin-Schiff/potassium hydroxide/periodic acid/fuchsin-Schiff sequence developed by Culling et al. frequently causes damage to sections and gives inconsistent results because of insufficient primary oxidation and difficulties in making the thionin-Schiff reagent. These disadvantages have been largely eliminated by more thorough primary oxidation and by replacing the original thionin-Schiff with a new cold thionin-Schiff. The effect of alkaline hydrolysis on thionin-aldehyde complexes was also studied and the reduction of color caused by this treatment was restored by a second thionin-Schiff reaction. The new sequence gives consistent results and imparts greater color to the thionin-Schiff reaction.     

An Improved Method for Determining Lipolytic Acyl-hydrolase Activity

The effects of 2-phthalimidooxyalkanoic acid derivatives on the germination and root-growth of cress were examined. Since 2-phthalimidooxypropionates were most effective, the optically active ethyl esters were prepared. As the result of biological testing, the (S)-(-)-isomer exhibited stronger activity than the (R)-(+)-isomer. This result is contrary to those from commercial herbicides with similar structures, phenoxy- and oxyphenoxy-propionate-type compounds, where the (R)-isomers are generally known to be the active principles.