湖州主要森林类型土壤肥力的灰色关联度分析与评价

土壤是一个由生物及非生物组成的复杂综合体、有集散、转化、传递物质和能量的作用 ,其综合作用称为肥力[3] 。土壤肥力是从环境条件和营养条件两方面供应和协调作物生长发育的能力 ,是土壤物理、化学和生物等性质的综合反映 ,土壤结构是肥力的重要基础[11] 。土壤肥力的差异是土壤基本特性的综合表现 ,是多因素的耦合[7] 。在评价土壤肥力时 ,要考虑土壤整体剖面。目前有关土壤肥力的定义至今没有适当的内涵和外延 ,缺少量化的指标[3] 。为此 ,笔者认为 ,土壤肥力评价 ,应着眼于系统的观点 ,根据评价土壤肥力的综合指标 ,以评判该种土壤的…     

野生诸葛菜蛋白质营养价值的评价研究

采用模糊识别法和氨基酸比值系数法,分别以鸡蛋蛋白质为标准蛋白,以WHO/FAO氨基酸参考模式为评价标准,对诸葛菜蛋白质营养价值进行了全面评价。并与12种豆科芽苗菜和野菜蛋白进行了对照比较,结果表明,诸葛菜蛋白质营养价值优于11种对照蔬菜。     

鸡冠花叶蛋白质营养价值的评价研究

应用模糊识别法和氨基酸比值系数法,分别以鸡蛋蛋白南为标准蛋白,以ＷＨＯ／ＦＡＯ氨基酸参考模式为评价标准,对３种鸡冠花叶蛋白质营养价值进行了全面评价,并与１０种常见叶菜蛋白进行对照比较。结果表明,３种鸡冠花叶（干品）蛋白质含量为２３．７％￣２７．４％,蛋白质中氨基酸种类齐全,其含量为８３．４７％￣８６．９４％,必需氨基酸（ＥＡＡ）占总氨基酸量的４０．２％￣４１．７％,第一限制性氨基酸为含硫氨基酸（Ｍ     

新疆长绒棉品种(系)的灰色关联度分析与综合评价

本文利用灰色关联度方法,把棉花产量和品质的15个性状指标集为一体进行分析,对参试品种(系)进行全面直观的综合评价,为新品种审定和大面积生产应用提供科学依据。     

基于灰色关联度分析的辽西地区典型种植模式评价

不同种植模式评价是当今种植制度研究中的热点之一,针对辽西地区自然特点和种植模式混杂多样的现状,在多年试验研究和专家问卷调查的基础上,采用灰色关联度分析方法对辽西地区6种典型种植模式进行了评价。结果表明:无论是在等权关联度下还是在侧重生态环境指标或经济指标的变权重下,南果梨+南瓜种植模式与参考模式的关联度均为最大,分别为0.867、0.920和0.841,南果梨+花生种植模式次之,说明南果梨+南瓜‖花生的林粮间作模式的生态和经济效益最好,是辽西地区发展种植业的最佳模式,玉米/大豆间作模式的关联度最小,分别为0.848、0.901和0.821,这种模式的生态和经济效益最差。该研究结果对保护辽西地区生态环境,发展多熟立体农业,推动该区域的社会经济与环境的协调发展提供了理论依据。     

运用灰色关联度法评价皮特兰猪在商品猪生产中的种用价值

目的:以评价皮特兰在商品猪生产中的种用价值.方法:本文运用灰色关联度法对含皮特兰血的5个组合杂交猪(皮杜、皮杜B、皮杜大、皮杜长大和杜长大)的瘦肉率、熟肉率、大理石纹评分、肉色评分、pH值、失水率和嫩度等7个肉质指标按等权关联度进行了综合评定.结果:"皮杜 B"肉质最优,其次是"杜长大"和"皮杜长大".结论:说明以提高瘦肉率为目标利用"皮杜"公猪,"皮杜长大"四系配套组合和"皮杜"公猪与培育品种杂交肉质最佳.     

三种蜂王浆蛋白质的营养评价

采用国际上通用的营养价值评价方法,全面评价了中蜂王浆、意蜂王浆和卡蜂王浆蛋白质的营养价值。三种王浆的必需氨基酸含量分别占其氨基酸总量的42.88%,40.98%和42.72%,含硫氨基酸为第一限制氨基酸。蛋白质的化学评分(CS)、氨基酸评分(AAS)、必需氨基酸指数(EAAI)、生物价(BV)、营养指数(NI)和氨基酸比值系数分(SRCAA)计算结果表明,三种蜂王浆都是良好的蛋白源,但中蜂王浆蛋白质的营养价值高于意蜂王浆和卡蜂王浆,明显与常规品质评价指标10-HDA的含量高低顺序不同。     

丹参品质与主导气候因子的灰色关联度分析

气候因子对丹参(Salvia miltiorrhiza Bunge)生长及有效成分含量有重要影响,为科学选择人工种植基地,需要明确影响丹参品质的主导气候因子。研究了丹参在商洛6个不同地区的生长量及有效成分含量差异,并应用灰色关联度分析了其与气候因子的关系,结果表明:6地区丹参有效成分含量均达到药典要求,但品质存在显著差异。年日照和年均降水量是影响丹参根系生长量的主导因子;无霜期与年极高温度是影响丹参素含量的主导因子;7月份均温、年均温度、年极高温度是影响丹参酮IIA含量的主导因子;年日照、无霜期是影响丹酚酸B含量的主导因子。以上几个指标可以作为选择丹参适生基地的参考指标,为科学合理的选择丹参规范化种植基地,保证中成药生产原料质量提供参考。     

贵州四种植物种子蛋白质的氨基酸研究

本文根据贵州所产四种植物种子或种仁,进行了蛋白质的氨基酸测定,采用氨基酸分析仪对它们进行定量。根据分析结果,本文主要讨论了四种植物种子蛋白质的氨基酸含量、种类及利用。     

一种新的蛋白质结构类预测方法

基于氨基酸的16种分类模型,给出蛋白质序列的派生序列,进而结合加权拟熵和LZ复杂度构造出34维特征向量来表示蛋白质序列。借助于贝叶斯分类器对同源性不超过25%的640数据集进行蛋白质结构类预测,准确度达到71.28%。     

Polyamine synthesis and salvage pathways in the malaria parasite Plasmodium falciparum

We demonstrate, for the first time, a functional polyamine biosynthetic pathway in the malaria parasite Plasmodium falciparum that culminates in the synthesis of spermine. Additionally, we also report putrescine and spermidine salvage in the malaria parasite. Putrescine and spermidine transport in P. falciparum infected red blood cells is a highly specific, carrier mediated and active process, mediated by new transporters that differ from the transporters of uninfected red blood cells in their kinetic parameters, Vmax and km, as well as in their activation energy.     

Polyamine metabolism during sclerotial development of Sclerotinia sclerotiorum

A study on polyamine metabolism and the consequences of polyamine biosynthesis inhibition on the development of Sclerotinia sclerotiorum sclerotia was conducted. Concentrations of the triamine spermidine and the tetramine spermine, as well as ornithine decarboxylase and S-adenosyl-methionine decarboxylase activities, decreased during sclerotia maturation. In turn, the concentration of the diamine putrescine was reduced at early stages of sclerotial development but it increased later on. This increment was not related to de novo biosynthesis, as demonstrated by the continuous decrease in ornithine decarboxylase activity. Alternatively, it could be explained by the release of putrescine from the conjugated polyamine pool. α-Difluoro-methylornithine and cyclohexylamine, which inhibit putrescine and spermidine biosynthesis, respectively, decreased mycelial growth, but did not reduce the number of sclerotia produced in vitro even though they disrupted polyamine metabolism during sclerotial development. It can be concluded that sclerotial development is less dependent on polyamine biosynthesis than mycelial growth, and that the increase of free putrescine is a typical feature of sclerotial development. The relationship between polyamine metabolism and sclerotial development, as well as the potential of polyamine biosynthesis inhibition as a strategy for the control of plant diseases caused by sclerotial fungi are discussed.     

Changes in Polyamine Concentrations in Amygdaloid-Kindled Rats

Concentrations of the polyamines putrescine, spermidine, and spermine were investigated in the left and right amygdala and in the remaining cerebrum, in which kindling was induced by repeated application of electrical stimulation of the left amygdala of rats. In kindled rats, the concentrations of spermidine and spermine increased slightly, but elevations did not reach significant levels in any brain regions. The most profound increase was detected in the putrescine concentration in all parts of the cerebrum 1-8 h after the final stimulation. These results suggest that the increases in concentrations of polyamines, particularly of putrescine, are involved in the pathogenesis of amygdaloid kindling.     

多胺类代谢与园艺作物生长发育关系研究进展

本文综述了国内外近年来对多胺类物质与园艺作物生长发育关系的研究报道。就多胺类的合成途径、对植物生长发育的调控作用以及在园艺作物上的应用进行了概述。     

Metabolism and function of polyamines in plants: recent development (new approaches)

A review is presented of the recent developments in the metabolism andfunction of polyamines in plants. Polyamines appear to be involved in a widerange of plant processes so their exact role is not completely understood. Inthis review, the metabolic pathways involved in polyamine biosynthesis anddegradation are explained, along with the transport and conjugation of thesecompounds. The methodologies involved in the analysis of polyamine functionusing metabolic inhibitors and genetic and molecular approaches are described.The occurrence and distribution of polyamine-derived alkaloids are also dealtwith. The direction of future research in the study of plant polyamines isindicated.     

Polyamine transport inEscherichia coli

Summary The polyamine content in cells is regulated by both polyamine biosynthesis and its transport. We recently obtained and characterized three clones of polyamine transport genes (pPT104, pPT79 and pPT71) inEscherichia coli. The system encoded by pPT104 was the spermidine-preferential uptake system and that encoded by pPT79 the putrescine-specific uptake system. Furthermore, these two systems were periplasmic transport systems consisting of four kinds of proteins: pPT104 clone encoded potA, -B,-C, and -D proteins and pPT79 clone encoded potF, -G, -H, and -I proteins, judging from the deduced amino acid sequences of the nucleotide sequences of these clones. PotD and -F proteins were periplasmic substrate binding proteins and potA and -G proteins membrane associated proteins having the nucleotide binding site. PotB and -C proteins, and potH and -I proteins were transmembrane proteins probably forming channels for spermidine and putrescine, respectively. Their amino acid sequences in the corresponding proteins were similar to each other. The functions of potA and -D proteins in the spermidine-preferential uptake system encoded by pPT104 clone were studied in detail through a combined biochemical and genetic approach. In contrast, the putrescine transport system encoded by pPT71 consisted of one membrane protein (potE protein) haveing twelve transmembrane segments, and was active in both the uptake and excretion of putrescine. The uptake was dependent on membrane potential, and the excretion was due to the exchange reaction between putrescine and ornithine.     

Polyamine derivatives from the bee pollen of Quercus mongolica with tyrosinase inhibitory activity

Eighteen constituents, including nine new compounds, were isolated from the bee pollen of Quercus mongolica. The structures of the new compounds were established on the basis of combined spectroscopic analysis. Structurally, the nine new compounds are polyamine derivatives with phenolic moieties which were assigned as one putrescine derivative, mogolicine A (2), seven spermidine derivatives, mongolidines A-G (3–5, 8, 12, 14, 17) and one spermine derivative, mogoline A (18). Evaluation of the biological activity of isolated compounds revealed that the polyamine derivatives with coumaroyl and caffeoyl moieties showed tyrosinase inhibition with IC₅₀ values of 19.5–85.8 μM; however, the addition of a methoxy group to phenolic derivatives reduced the inhibitory activity.     

Conversion of exogenous spermidine into putrescine after administration to rats

Administration of large, but non-toxic doses of spermidine (0.4–1.25 mmol/kg) led to a substantial increase in putrescine in liver, kidney and a number of other tissues including muscle. The increase in putriscine peaked at 6 h after treatment and was completely prevented by administration of cycloheximide 3 h after the spermidine suggesting that the induction of a new protein was required. This protein is likely to be spermidine N¹-acetyltransferase which was induced by the treatment with spermidine and increased 3–4-fold in liver and kidney within 6 h. N¹-Acetylspermidine was detected in tissues at this time after spermidine treatment and experiments in which labeled spermidine was given indicated that a substantial fraction of the administered spermidine was converted into N¹-acetylspermidine and into putrescine. These results suggest that the rise in putrescine after spermidine treatment is brought about by the production of N¹-acetylspermidine which is converted into putrescine by the action of polyamine oxidase. The limiting step in this conversion is the activity of the acetylase which is induced in response to the rise in spermidine content. The acetylase/oxidase pathway, therefore, provides a means by which polyamine levels can be regulated and excess polyamine disposed of.