根瘤菌培养基的优化和剂型的比较研究*

以费氏中华根瘤菌 (Sinorhizobiumfredii)HN0 1和大豆慢生根瘤菌 (Bradyrhizobiumjaponi cum)USDA1 1 0作为供试菌 ,进行YMA、TY、SM、PA和BSE等 5种培养基的比较试验。结果表明 ,两种菌都在BSE中生长速度最快。对USDA1 1 0进行培养基的优化试验 ,筛选出一种能将生长速度提高 2倍左右的优化培养基。制作了供试菌的固体、液体与冻干菌剂 ,结果表明在 3种供试固体剂型载体中 ,草炭要优于蛭石 ,蛭石又优于珍珠岩。供试菌在两种液体剂型中的存活率和活菌数均较高 ,氮气或真空剂型对存活率的影响没有明显的差别。两种冻干菌剂的结果表明 ,供试菌在冻干过程中的死亡率较高 ,液氮冻干优于常规冻干。冻干菌剂在储存条件下的存活率为 : 2 0℃ >4℃ >室温     

SIZE DEPENDENCE OF GROWTH RATE,RESPIRATORY ELECTRON TRANSPORT SYSTEM ACTIVITY,AND CHEMICAL COMPOSITION IN MARINE DIATOMS IN THE LABORATORY1

The dependence of growth, electron transport system activity and chemical composition on the size of diatoms was examined during the exponential phase of growth. The six different marine centric species compared ranged in volume from 7.7 μm³ to 62 × 10⁵μm³. A size dependence was observed for growth, ¹⁴C uptake, respiration and the productivity index (¹⁴C/chl a). Although the size dependence of all parameters was similar, the results indicate that on a carbon basis, growth efficiency decreases with increasing size. The C/N and C/chl a ratios were not size dependent. The importance of the surface area to cell volume ratio, and the importance of carbon per unit volume in determining the observed size dependence are discussed.     

PHOTOSYNTHETIC ELECTRON TRANSPORT IN CELL-FREE EXTRACTS OF DIVERSE PHYTOPLANKTON1,2

A simple and rapid procedure for preparing thylakoid membranes that are active in photosynthetic electron transport from diverse phytoplankton species is described. The method requires disruption of algal cells with glass beads, exposure to mild hypotonic stress, and subsequent enrichment of the thylakoid membranes by differential centrifugation. Isolated thylakoid membranes were assayed for photosynthetic electron transport activity by measuring rates of oxygen consumption and oxygen production, using a variety of electron donors and acceptors. In the dinoflagellate Gonyaulax polyedra Stein, a relatively broad pH optimum between 7.0 and 8.0 was determined for the whole chain electron transport from water to methyl viologen. The preparation maintained maximum activity for 45 min following the preparation. The assay for photosystem I activity in G. polyedra, determined as electron flow from ascorbate/2,6-dichlorophenolindophenol to methyl viologen, had a somewhat narrower pH optimum around 8.0. Rates of whole chain photosynthetic electron transport on a per cell and on a per chlorophyll a basis were shown to decrease dramatically with cell age in batch cultures of G. polyedra. Using the procedures optimized for G. polyedra, reproducible rates of electron transport on a per cell chlorophyll a basis were also measured in cultures of the dinoflagellate Glenodinium sp., the diatom Nitzschia closterium (Ehrenberg 1839) Wm. Smith 1853 and the chrysophyte Monochrysis lutheri Droop {= Pavlova lutheri (Droop) Green}. Other electron transport assays applied to G. polyedra, and that resulted in comparable rates to those found in other algal groups, include the photosystem II assay from water to diaminodurene/ferricyanide and the photosystem I assay from durohydroquinone to methyl viologen.     

ANATOMY OF MACROZAMIA COMMUNIS LATERAL ROOTS AND ROOT NODULES FORMED IN VITRO STUDIED WITH LIGHT AND SCANNING ELECTRON MICROSCOPY

The anatomy of Macrozamia communis L. Johnson lateral roots and nodules was studied following axenic culture in light and darkness. Pointed lateral roots from dark cultures had an open apical organization similar to that of other cycads and gymnosperms. A distinct protoderm-derived epidermis was not observed. At the apex, the dermis was formed by the outer root capcortical cell layer. Subapically, the outer cortex formed the dermis. No evidence of an algal zone was observed in these roots. The stele was bounded by a distinct endodermis and contained an exarch, diarch xylem. Apogeotropic nodules which developed at the root-shoot junction in darkness, branched dichotomously and had rounded tips covered by tangentially-enlarged root cap cells. The root cap was reduced to a few cell layers and was confined to the extreme nodule apex. The central region of the apical meristem was enlarged, and meristematic cells contained differentiated amyloplasts. A presumptive algal zone was present in some but not all nodules and divided the cortex into inner and outer regions. Stelar anatomy was similar to that observed in pointed, dark-grown lateral roots, except that there was greater xylem differentiation. Nodules which developed in the light were similar to dark-formed nodules, except that root cap cells were radially enlarged and extended over the flanks of the nodule forming a persistent root cap. The heteromorphic lateral roots of M. communis formed a developmental continuum not a heterorhizic root system.     

MAIZE ENDOSPERM TISSUE GROWN IN VITRO III. DEVELOPMENT OF A SYNTHETIC MEDIUM

Straus , Jacob . (U. Oregon, Eugene.) Maize endosperm tissue grown in vitro. III. Development of a synthetic medium. Amer. Jour. Bot. 47(8) : 641–647. Illus. 1960.—The development of a synthetic medium for the growth of endosperm tissue cultures derived from the maize variety, ‘Black Mexican Sweet,‘ is described. Previously, these tissues required yeast extract, casein hydrolyzate, or tomato juice in the medium in order to grow. The growth-supporting activity of these complexes could be attributed to their organic nitrogen content. The effect of juice extracted from fresh tomatoes is enhanced by autoclaving under acid conditions. Presumably this treatment increases the free amino acid content of the tomato juice. One-dimensional paper chromatograms of tomato juice autoclaved under acid conditions indicated the presence of a large amount of free amino acids. Addition of 1.5 × 10^–2 M asparagine to the basal mineral-sugar-vitamin medium (White's medium plus Nitsch's trace-element solution) resulted in better growth than that supported by yeast extract, tomato juice, or casein hydrolyzate. Arginine was ineffective. Glutamine, glutamic acid and aspartic acid (all at 1.5 × 10^–2 M) supported appreciable growth of the tissue but none of them were nearly so good as asparagine in this respect. Thus, a medium containing minerals, sugar, vitamins, and asparagine is capable of supporting excellent growth of maize endosperm tissue cultures.     

GLUCOSE TRANSPORT SYSTEMS AND GROWTH CHARACTERISTICS OF BRACTEACOCCUS MINOR1,2

Bracteacoccus minor grows on glucose both in the dark and in the light. However, the growth rates at 50 ft-c or higher in the presence of glucose are considerably lower than those in inorganic media at the same intensities. The lowered growth rates in the presence of glucose appear to be related to changes in metabolism toward increased production of storage carbohydrates. Glucose shortens the length of the lag phase at high light intensities and increases the length of the exponential phase at all light intensities, resulting in very high cell yields compared to cultures grown in inorganic media. B. minor has 2 transport systems for glucose: (1) a high affinity system, K_S=1 × 10^?5 M, which is formed in the dark in the absence of external glucose; and (2) a low affinity system, K_S=5 × 10^?4 M, which appears to be constitutive. At high concentrations of glucose there is also significant free diffusion of glucose into the cells. The glucose analog, 3-O-methyl glucose, is also taken up by the inducible system, but at a lower rate than glucose. It is Acumulated, about 2000 times in a 20-min incubation period, indicating active transport. Cycloheximide inactivates the high affinity system to the same extent as high light intensities, and also prevents induction of this system in the dark. Rates of photosynthesis are inversely correlated to glucose uptake rates over a range of light intensities of pre-incubation. The possession of a light-regulated high-affinity transport system as well as a constitutive low-affinity system for glucose is probably of competitive advantage to this alga in the soil environment.     

TRANSPORT OF CHOLINE ACETYLTRANSFERASE AND ACETYLCHOLINESTERASE IN THE RAT SCIATIC NERVE: A BIOCHEMICAL AND ELECTRON HISTOCHEMICAL STUDY

The transport of acetylcholinesterase (AChE) and choline acetyltransferase (ChAc) were investigated by biochemical and histochemical methods. After ligature of one of the sciatic nerves of the rat for varying times—4, 14, 20 and 44 h—the normal levels and the accumulation of AChE and ChAc activities were investigated. It can be inferred from the results that there is a rapid accumulation of AChE activity just proximal to the ligature, while the increase in ChAc activity is less pronounced. Distal to the ligature the level of AChE is above the control value whereas, in contrast to this, the ChAc activity is significantly decreased. Histochemical demonstration of the two enzymes indicates that they are present in the cholinergic axons. The reaction end-product produced by AChE occurs within vesicles and neurotubules, while the endproduct due to ChAc appears to be free in the axoplasm, bound to neurofilaments and on the outer surface of vesicles and tubules.     

绿豆线粒体呼吸链在不同电子传递途径中的电子漏

绿豆线粒体的呼喊链在氧化不同义莪时有不同的呼吸速率和电子漏速率,但是Ｏ２＾－／Ｏ２比值较稳定。呼吸链部位Ⅱ的抑制剂抗霉素Ａ对α－酮茂二酸、琥珀酸及苹果本工物时的电子漏速率和Ｏ２＾－／Ｏ２比值都明显的促进作用,说明电子漏发生的位点可能在抗纱Ａ的抑制点之前。呼吸链在氧化外源ＮＡＤＨ时,线料体所产生的地氰化物、鱼藤酮、抗弱Ａ及ＳＨＡＭ都不敏感,而对钙离子的螯合剂ＥＧＴＡ显著敏感。因此,依赖于钙离子的ＮＡ     

SERUM FRACTIONATION AND THE EFFECTS OF BOVINE SERUM FRACTIONS ON HUMAN CELLS GROWN IN A CHEMICALLY DEFINED MEDIUM

Serum has been fractionated by curtain electrophoresis using carboxymethyl cellulose dissolved in sodium bicarbonate electrolyte. Various fractions were produced from bovine serum and added to replicate cultures of Chang's endoepithelial cells and HeLa cells grown in a chemically defined medium. The effects of each of the various fractions on the appearance of the cultures and on cell multiplication were studied. Three different fractions were obtained and two were subjected to further purification. One fraction associated with albumin promoted survival, attachment, and flattening as well as cell multiplication. A second fraction associated with the alpha globulins promoted survival and multiplication of some cells. A third fraction caused cells to aggregate and form free floating clumps. An adequate chemically defined medium for continuous growth of human cells was used throughout the study. The response of cells to alterations in their environment which simulated some of the effects produced by serum fractions is described.     

Photosynthesis in Fescue: I. HIGH RATE OF ELECTRON TRANSPORT AND PHOSPHORYLATION IN CHLOROPLASTS OF HEXAPLOID PLANTS

Chloroplasts isolated from tall fescue, Festuca arundinacea Schreb., showed high rates of electron transport, comparable to rates observed for spinach chloroplasts.     

脂氧合酶对黄瓜叶片光合电子传递活性的影响

黄瓜（Ｃｕｃｕｍ ｉｓｓａｔｉｖｕｓＬ．）叶片的光合作用与电子传递活性随叶片衰老而降低,脂氧合酶（Ｌｏｘ）活性则相应增高。大豆Ｌｏｘ－１ 抑制黄瓜子叶分离的叶绿体ＰＳⅡ电子传递活性,没食子酸丙酯（ＰＧ）或槲皮酮（ＰＦ）能消除这种抑制作用。二氯苯二甲脲（ＤＣＭＵ）或２,３－二溴百里香醌（ＤＢＭＩＢ）存在时,大豆Ｌｏｘ－１ 对ＰＳⅡ电子传递活性有抑制作用,加入ＰＧ 使活性恢复到接近原有水平。二苯卡巴肼（ＤＰＣ）对经Ｌｏｘ－１ 处理的叶绿体ＰＳⅡ电子传递活性有明显恢复作用。Ｌｏｘ－１ 使Ｃｈｌａ室温荧光Ｆｍ 降低,ＤＰＣ则能轻微恢复Ｆｍ 。可见,ＰＳⅡ氧化侧、Ｑ与ＰＱ 位点都对Ｌｏｘ－１ 的作用敏感。Ｌｏｘ－１ 对叶绿体色素的漂白作用,以及活性氧对ＰＳⅡ电子传递活性的抑制,可能是Ｌｏｘ 影响光合膜功能的重要原因之一     

大豆根瘤菌接种试验的系统聚类分析

本文研究了在种植大豆的老区,用3种Rhizobiumiaponicum进行单菌接种、混菌接种和混菌接种加施过磷酸钙等7个处理的田间对比试验,并选取22个分类性状,采用系统聚类分析方法,进行数学运算．结果表明,系统聚类分析的6种方法,均得到满意的结果．其中,以离差平方和法和最长距离法为佳,即用R.japonicum61A76、R.japomicum005和R.japoioumSm31分别接种与CK对比,单位面积产量均有所增加,但以3种R．japonicum各1／3混菌接种或混菌接种加施过磷酸钙增产更为显著,增产幅度13.03～15.14％．     

植物的磷营养：磷酸盐运转系统及其调节

对近年来植物磷营养中有关Ｐｉ运转系统及其调节等方面的研究进展进行简要介绍,并对今后有关的研究趋势作了初步展望。     

紫云英根瘤菌质粒功能研究

紫云英根瘤菌CH203含有3条质粒(pRHa,97MI);pRHb,168MD;pRHc,251MD为共生质粒),用带蔗糖敏感基因Tn5-sacB进行菌株质粒消除和质粒缺失突变株筛选,获得一系列突变株。与野生型菌相比,质粒pRHa的丢失导致菌株结无效根瘤,质粒pRHb的丢失使菌株失去共生能力,在TY培养基平板上菌落变得粗糙,失去了脂多糖(LPSI)。质粒pRHc(共生质粒)的丢失显然失去其菌株的共生能力,同时使菌株抗酸性明显减弱。质粒回复能恢复突变株的表现特征和共生能力。此外,紫云英根瘤菌CH205含有5条大小不同的质粒(分子量42MD～230MD),该菌株某些质粒的消除能显著增强菌株的结瘤固氮能力。研究结果也表明除共生质粒外,紫云英根瘤菌其它质粒明显影响菌株的共生效应。