Characterization of acetylcholinesterase and its molecular forms in organs of five freshwater teleosts

The activity and molecular forms of acetylcholinesterase (AChE, EC 3.1.1.7) were characterized in the brain, heart, white skeletal muscle and liver of the Siberian sturgeon (Acipenser baeri), European eel (Anguilla anguilla), wels (Silurus glanis), common carp (Cyprinus carpio) and silver carp (Hypophthalmichthys molitrix), belonging in four families. The brain had the highest (between 183.2±10.6 and 1361.2±189.7 mU mg^-1 protein and between 4.7±0.4 and 23.5±2.7 U g^-1 wet tissue) and the liver the lowest (between 25.3±1.9 and 126.5±22.7 mU mg^-1 protein and between 1.0±0.1 and 4.5±0.5 U g^-1 wet tissue) activity in all these fish, with the exception of the wels, where the heart contained the smallest amount of AChE (26.2±7.5 mU mg^-1 protein and 1.2±0.3 U g^-1 wet tissue). The highest tissue AChE activity was found in the carp and lowest in the sturgeon. The solubility properties and molecular forms of AChE in the four tissues were studied by extraction in high-salt medium (1.0 M NaCl) with and without the detergent Triton X-100 (0.5%, v/v). The proportions of detergent-soluble (DS) and salt-soluble (SS) forms of AChE varied considerably from one species to another, but a general tendency could be observed: the proportion of DS AChE was generally higher in the brain (between 70.4±4.1 and 82.5±1.2%) and lower in the heart (between 12.0±2.0 and 51.3±2.3%) and skeletal muscle (between 16.0±2.0 and 64.4±0.7%). Velocity sedimentation centrifugation revealed that most tissues contained the G₄ or A₄ form. Three tissues (brain, heart, and liver) of the Siberian sturgeon contained a relatively high proportion of the G1 form (between 24.3±2.4 and 28.6±4.9%), while the skeletal muscle of the wels contained only the most complex type of AChE, i.e., A₁₂. Amongst the tissues studied, the brain and liver mostly contained amphiphilic globular forms of the G₄ type, while the heart and skeletal muscle were rich in asymmetric forms (A₄ and A₁₂). It was concluded that the differences revealed in the activities of AChE and in the distribution of its molecular forms may be connected with the variation in behavioral habits (feeding and swimming patterns), and the developmental stage of the nervous system.     

两种形态蛹虫草菌株子实体及有效成分比较

在蛹虫草资源调查中,发现两种子实体形态迥异的蛹虫草菌株T和G。栽培试验表明,T菌株子实体矮化膨大,G菌株子实体为棒状．两者子实体长度、直径和产量差异显著。有效成分测定结果表明,菌株T和G子实体中粗多糖的含量分别为1．75％,1．77％,虫草酸为2．81％,2．57％,超氧化物歧化酶（SOD）酶活分别为30．43U／mgprotein、53．49U／mgprotein,过氧化物酶（POD）分别为31．26U／mgprotein,33．49U／mgprotein,过氧化氢酶（CAT）分别为126．35U／mgprotein、137．46U／mgprotein。其中,虫草酸含量、SOD酶活两者差异均显著。     

多酶金缓释尿素对土壤氮素形态和含量及油菜产量的影响

采用盆栽试验和室内分析化验相结合的方法,研究了多酶金缓释尿素对油菜田土壤氮素及油菜植株全氮含量、氮肥利用率和土壤氮素依存率的影响。结果表明,多酶金缓释尿素在石灰性褐土中抑制尿素水解显著有效作用时间在油菜移栽后20 d以内,20 d以后多酶金缓释尿素处理的土壤铵态氮、硝态氮和无机氮分别为5.26,9.08,14.34 mg/kg,显著高于多酶金尿素和普尿;多酶金缓释尿素处理的土壤有机氮、全氮和植株全氮比多酶金尿素和普尿分别提高了13.55%,13.67%,9.85%和21.75%,21.82%,19.60%,且差异显著;多酶金缓释尿素处理的氮肥利用率最高,为45.19%,土壤氮素依存率和氮素损失最低,分别为40.13%和1.21 g/盆,而多酶金尿素处理的油菜产量比多酶金缓释尿素和普尿分别提高了5.38%,8.11%,这可能与肥料释放养分特点和油菜生长特性有关。     

不同硫浓度下叶面施硒对水稻幼苗镉的亚细胞分布及化学形态的影响

采用水培的方式,通过叶面喷施硒(Se),根部施加硫(S)与镉(Cd),研究了不同硫浓度下叶面施硒对水稻幼苗体内Cd的亚细胞分布和化学形态的影响。结果表明,在不同处理条件下,细胞壁组分所占比例均为Cd10Cd1(Cd10代表浓度为10 mg·L-1的Cd,下同)。随着S的增加以及叶面施Se可溶性组分中Cd的比例有所升高,表明S与Se的供应能促进Cd向液泡转移。NaCl提取态所占比例趋势为S720S48S0、Se500Se0,而乙醇和去离子水等活性较高的提取态所占比例有所下降,说明S的添加以及叶面施Se能够促使Cd向活性较低的提取态转移。然而相对于无S,在高浓度S情况下,施Se并未显著增加Cd在液泡中以及FNaCl提取态的比例,推测S与Se之间相互竞争,从而未产生协同作用。     

鄂尔多斯地区历史城市的城市平面组合和子城特征

结合文物资料和前人的研究成果,在2003～2007年多次野外实地考察的基础上,对我国农牧过渡带-鄂尔多斯高原及毗邻地区内209座历史城市的城市平面组合和子城进行了研究。鄂尔多斯高原及毗邻地区历史时期的城市平面组合形式大致可分为两种:独立组合式和相连并列式。汉代城市的子城周长大致符合晁错的设计规模;子城以偏于地势较高和利于防卫的城内一隅为最常见的形态;子城作为城市中枢系统衙署所在,在位置选择中要得到最好的防御保障。     

模拟消化体系中乳及发酵乳对铁化学状态及透析率的影晌

本文通过体外消化来模拟消化系统以研究乳及发酵乳对FeCl3中铁的化学状态及透析率的影响，结果表明，在消化过程中乳及发醇乳可促进铁的溶解、以及Fe3 的还原和铁的透析，这一作用与样品的pH元失，认为是消化过程中产生的氨基酸和肽起了作用。研究还发现，原乳先加铁盐再送行发酵所产生的作用要较发醇后再加铁盐的作用大，认为发醇乳对铁化学状态及透析率的影响具有时间效应。此外，有乳存在的各试验组其Fe3 透析率较可溶性铁的透析率与对照组差异更大。     

渗透胁迫对玉米幼苗叶片不同形态多胺含量的影响

用高压液相色谱法，研究了玉米品种农大108（抗旱性较强）和掖单13（抗旱性较弱）幼苗叶片中游离态(free, f)、酸可溶性共价结合态(AS-conjugated)和酸不溶性共价结合态(AIS-bound) 多胺（polyamine, PA）与渗透胁迫的关系。结果发现，渗透胁迫7 d，农大108的fSpd和fSpm的含量显著(P＜0.05)上升，而掖单13的fPut的升幅显著(P＜0.05)。用S-腺苷蛋氨酸脱羧酶（SAMDC）抑制剂甲基乙二醛-双（鸟嘌呤腙）（MGBG）处理农大108，显著抑制了渗透胁迫诱导的fSpd和fSpm的增加，并且加重了渗透胁迫伤害，用外源Spd处理掖单13，则显著促进了渗透胁迫诱导的fSpd和fSpm的增加，并且减缓了渗透胁迫的伤害。渗透胁迫下，农大108幼苗叶片中AS-conjugated-PA和AIS-bound-PA的上升幅度都显著大于掖单13。用转谷氨酰胺酶（TGase）抑制剂菲咯啉(o-Phen)处理，则抑制了渗透胁迫诱导的AIS-bound-PA含量的上升，并加重了渗透胁迫的伤害。上述结果说明，玉米幼苗叶片中的fSpd、fSpm、AS-conjugated-PA和AIS-bound-PA的升高有利于增强幼苗的抗渗透性。     

An Effect of Various Nitrogen Forms Used as Fertilizer on Lupinus albus L. Yield and Protein, Alkaloid and α-Galactosides Content

The influence of various forms of nitrogen supplied to the ground as N₂, NH, NO, [NH + NO], –NH₂, and Nd (N‐deficiency) on Lupinus albus L. cvs. Butan (sweet) and Bac (bitter) yield and protein, alkaloid and α‐galactoside biosynthesis in their seeds were studied. The experiments were performed in a greenhouse on perlite using, in all cases, the same dose of P, K, Mg and micronutrients (B, Zn, Mn, Cu, Mo, Fe). The Nd treatment contained only macro‐ and micronutrients without any nitrogen support. We found that different nitrogen forms used as a fertilizer had a significant influence on the development and yield structure of both lupin cultivars. It was found that the plants developed most favourably when nitrogen was supplied as N₂ and [NH + NO]. For the other forms, the anomalies like necrosis, chlorosis, leaves with small surface of assimilation were noticed. However, these observations were not always reflected by all parameters of yield structure. The forms of nitrogen had a pivotal influence on yield of generative and vegetative parts of lupin. Moreover, significant differences in protein, alkaloid and α‐galactoside content in seeds were observed.     

Agronomical and morphological differentiation among winter and spring triticales

A collection of 299 secondary hexaploid triticale cultivars and advanced breeding lines from 18 countries, which were considered a representative sample of the existing diversity, was evaluated for morphological and agronomical characters with autumn planting at Lleida, Spain, from 1988 to 1991. The entries were classified as having winter (84) or spring (215) growth habit and among this latter group were complete (73) or substituted (147) types according to CIMMYT's terminology. Winter and spring triticales were grouped by cluster and principal component analyses. Winter triticales were taller with longer growth cycles, longer spikes, and more spikelets per spike than spring types. At early stages they also had prostrate growth. Spring-substituted types were separated from complete material. As a group, spring-substituted triticales differed more from winter types than the spring complete genotypes, which showed intermediate characteristics. Complete types of spring habit had tendency to be taller, with longer spikes, more spikelets per spike and bigger and heavier grains than substituted triticales. Greater variation in morphological and agronomical parameters was detected among winter triticales followed by the complete-spring group.     

Characterization of organic phosphorus in leachate from a grassland soil

The degree of eutrophication in fresh water ecosystems may be influenced by the forms of phosphorus (P) leached from agricultural systems. Physico-chemical fractionation of P in leachate from a grassland soil carried out over a two year period indicated that the majority of the P loss from the Lismore soil occurred in unreactive particulate (55-76%) P forms. ³¹P nuclear magnetic resonance analysis of a selected leachate sample indicated that unreactive P was mainly comprised of monoester and diester forms of organic P. The presence of phosphomonoesterase (20-200 μg p nitrophenol l⁻¹ h⁻¹) and phosphodiesterase (68 μg bis-p nitrophenol l⁻¹ h⁻¹) activity in leachate resulted in hydrolysis of 10-21% of total unreactive P (TUP), indicating that some of the monoesters and diesters can be eventually hydrolyzed into inorganic P forms during P transport. Enzyme hydrolysis showed that 23% of the TUP was present as labile monoester P (LMP), followed by 20% as inositol hexakisphosphate (IHP) and 14% as diesters (phospholipids and nucleic acids). The findings of this study suggest that LMP, IHP and diesters are an important component of organic P leaching from the grassland soil.