濒危植物矮牡丹无性系分株种群的结构

矮牡丹（Paeonia suffruticosa Andr.var.spontanea Rehd.)无性系分株种群结构的研究结果表明：7个样地矮牡丹的年龄结构可划分为4类：强增长型、平缓增长型、稳定适应型和波动型,前3类种群的数量动态符合负指数方程y=e^a-bx。表现结构为单株高度不超过120cm,基径不超过2cm。适宜生境为地带性顶极群落辽东栎林。     

中国前胡属酯酶同工酶与种类演化和地理分布格局

利用聚丙烯酰胺凝胶电泳方法分析比较我国前胡属(PeucedanumL.)18种4变种的叶片酯酶同工酶酶谱,并结合形态特征和地理分布,从基因位点分布规律出发,探讨该属种间亲缘关系和地理分布格局。前胡属种类的酯酶同工酶酶谱能较好地反映种间的亲缘关系,基因位点随所分析种类的地理分布而呈现出明显的地带性变化。讨论了滨海前胡(P.japonicumThunb.)、马山前胡(P.mashanenseShanetSheh)和广西前胡(P.guangxienseShanetSheh)、石防风〔P.terebinthaceum(Fisch.)Fisch.exTurcz.〕和宽叶石防风〔P.terebinthaceumvar.deltoideam(MakinoexYabe)Makino〕、红前胡(P.rubricauleShanetSheh)和刺尖前胡(P.elegansKomarov),以及华中前胡(P.medicumDunn)和华北前胡(P.harrysmithiiFeddeexWolff)等种类的酯酶同工酶酶谱类型与系统演化的关系。根据前胡属植物区系,将我国前胡属分成7个酯酶同工酶地理表型。     

Using computer algebra to determine rate constants in biochemistry

In earlier work we have described how computer algebra may be used to derive composite rate laws for complete systems of equations, using the mathematical technique of Gröbner Bases (Bennett, Davenport and Sauro, 1988). Such composite rate laws may then be fitted to experimental data to yield estimates of kinetic parameters. Recently we have been investigating the practical application of this methodology to the estimation of kinetic parameters for the closed two enzyme system of aspartate aminotransferase (AAT) and malate dehydrogenase (MDH) (Fisher 1990a; Fisher 1990b; Bennett and Fisher, 1990): $$\begin{gathered} aspartate + \alpha - ketoglutarate\begin{array}{*{20}c} \rightharpoonup \\ \leftharpoondown \\ \end{array} glutamate + oxaloacetate \hfill \\ {\text{oxaloacetate + NADH}}\begin{array}{*{20}c} \rightharpoonup \\ \leftharpoondown \\ \end{array} malate + NAD^ + \hfill \\ \end{gathered} $$ In this paper we present a fuller (although not yet complete) analysis of the system. We show how symbolic estimates of the error behaviour of the parameters can be made, and used to identify those which are of kinetic significance. Finally we consider how metabolic control analysis can be applied directly to such a system.     

A simple method for measuring signs of <Superscript>1</Superscript>H<Superscript>N</Superscript> chemical shift differences between ground and excited protein states

NMR relaxation dispersion spectroscopy is a powerful method for studying protein conformational dynamics whereby visible, ground and invisible, excited conformers interconvert on the millisecond time-scale. In addition to providing kinetics and thermodynamics parameters of the exchange process, the CPMG dispersion experiment also allows extraction of the absolute values of the chemical shift differences between interconverting states, | \Updelta [(w)\tilde] | \left| {\Updelta \tilde{\omega }} \right| , opening the way for structure determination of excited state conformers. Central to the goal of structural analysis is the availability of the chemical shifts of the excited state that can only be obtained once the signs of \Updelta [(w)\tilde] \Updelta \tilde{\omega } are known. Herein we describe a very simple method for determining the signs of ¹H^N \Updelta [(w)\tilde] \Updelta \tilde{\omega } values based on a comparison of peak positions in the directly detected dimensions of a pair of ¹H^N–¹⁵N correlation maps recorded at different static magnetic fields. The utility of the approach is demonstrated for three proteins that undergo millisecond time-scale conformational rearrangements. Although the method provides fewer signs than previously published techniques it does have a number of strengths: (1) Data sets needed for analysis are typically available from other experiments, such as those required for measuring signs of ¹⁵N \Updelta [(w)\tilde] \Updelta \tilde{\omega } values, thus requiring no additional experimental time, (2) acquisition times in the critical detection dimension can be as long as necessary and (3) the signs obtained can be used to cross-validate those from other approaches.     

Analysis of tracer experiments V: Integral equations of perturbation-tracer analysis

An integral equation approach to perturbation-tracer analysis in steady-state multicompartment systems is formulated. The theory is developed for δ function perturbation and tracer inputs and extended to the case of continuous small perturbations and continuous tracer inputs. It is shown that the first order dependence of the initial entry function can then be expressed by means of an integral equation:

$$B_1 (t) = \int_{t_2 = - \infty }^\infty {\int_{t_1 = - \infty }^\infty {P(t_1 )T(t_2 )B_1 (t - t_2 ,t_1 - t_2 )dt_1 dt_2 } } $$     

绵刺的生物学特性及其保护

绵刺是蒙古高原特有的单种属植物,已列为国家二级重点保护植物。系统综述了绵刺的生态生物学特性,并探讨了其适应性,研究结果表明,绵刺具有典型旱生植物的结构和特征。耐旱、耐盆瘠、耐盐碱和抗风蚀能力较强,对恶劣的环境条件具有良好的适应性。另外还分析了绵刺濒危的可能原因并提出了保护措施。     

黄芩组织培养同源四倍体的诱导

应用组织培养技术对黄芩进行多倍体诱导,结果表明：组织培养条件下,在培养基中添加一定浓度和秋水仙素,或者把带有绿色芽点的黄芩愈伤组织经０．２％秋水仙素溶液浸泡一定时间后再进行培养,均可诱发黄芩多倍体的产生,但以后效果较好,诱导率可达４０．０％,通过试管苗根尖染色体显微观察,鉴定出５０多个黄芩同源四倍体,为今后优良品种的选育打下基础。     

Fmoc固相合成JFT的工艺研究

目的:研究多肽JFT的合成工艺。方法:本实验采用固相合成法(spps),以Fmoc—氨基酸为原料,TBTU\HoBt\DIEA混合试剂缩合,用三氟乙酸\苯甲硫醚\巯基乙醇\苯酚\水脱保护,将多肽从MBHA树脂上切割下来。结果:粗肽的收率为62%,经RP-HPLC纯化,即可获得纯度在98%以上的目标肽。经MALDI—MS质谱分析其分子量与理论值一致。结论:此工艺操作简单,便于推广,适合大规模生产。     

E-waste projection using life-span and population statistics

Purpose

E-waste is the most rapidly growing problem throughout the world, which has serious future concerns over its management and recycling. This article proposes a simple approach for future e-waste projection which can be obtained by using life-span data of various electronic items along with incorporation of population statistics.

Methods

For this purpose, 7-year sales data of electronic items were collected, which is then used to generate various mathematical equations. These mathematical relations are then modified by incorporating life-span and population data.

Results and discussion

By comparing sales data with their life-span (average) and population statistics, future e-waste can be quantified both in terms of specified area under investigation and proposed estimation area. The following equation is thus proposed: E - waste In terms of quantity = m Waste projection year ? Life - span ? Initial data collection year + C × Population of estimation area Population of study area $$ \begin{array}{c}\mathrm{E}-\mathrm{waste}\;\\ {}\left(\mathrm{In}\ \mathrm{terms}\ \mathrm{of}\ \mathrm{quantity}\right)=\left[m\left\{\mathrm{Waste}\;\mathrm{projection}\;\mathrm{year}-\mathrm{Life}-\mathrm{span}\right\}-\mathrm{Initial}\ \mathrm{data}\ \mathrm{collection}\ \mathrm{year}+C\right]\times \frac{\mathrm{Population}\ \mathrm{of}\ \mathrm{estimation}\ \mathrm{area}}{\mathrm{Population}\ \mathrm{of}\ \mathrm{study}\ \mathrm{area}\ }\end{array} $$ Where m and C can be obtained from plotting year-wise sales data over Excel sheet.

Conclusions

Local as well as global projection of future e-waste can be possible with the help of final equation.     

陕北黄土高原森林植被数量分类及环境解释

通过对陕北黄土高原森林群落的系统聚类分析和因子分析（FA）及其与5个土壤变量的多元统计分析。定量研究了该地区森林植被的类型及土壤特征之间的相互关系。结果表明,陕北黄土高原森林植被可分为5个群系,即油松林、辽东栎林、山杨林、白桦林和侧柏林,聚类分析结果与传统分类的结果完全一致。该地区森林植被格局可由群落土壤条件的差异来解释,土壤因子中含水量、全氮和有机质是主导性因素,各群落沿此梯度呈现出一定的分布格局,其它土壤因子的作用并不明显。     

大气一氧化碳浓度升高对植物生长的影响

大气ＣＯ２浓度同对植物生长有促进作用,对Ｃ３植物生长的促进作用最大。短期ＣＯ２浓度升高时,植物光和速率增加;在长期ＣＯ２浓度升高条件下,植物光鸽上降并发生光合适应现象。这可能是植物在长期ＣＯ２浓度升高条件下植物源库关系不平衡引起的反馈抑制作用以及营养吸收不能满足光合速率增加的需要所引起Ｒｕｂｉｓｅｏ活必和含量下降。在ＣＯ２浓度升高条件下植物的呼吸也会发生变化,根的分枝和数量增多,根系的分泌量和吸收     

中国结缕草属植物( Zoysia spp.)地上部分形态类型多样性

通过对结缕草属 (ZoysiaWilld .)植物地上部分 18个形态性状的的聚类分析 ,将产于中国的 78份结缕草种质划分为 6组 ,结缕草 (Z .japonicaSteud .)和中华结缕草 (Z .sinicaHance)具有较典型的特征而各自成组 ,细叶结缕草(Z .tenuifoliaWilld .)和沟叶结缕草〔Z .matrella (L .)Merr.〕为一组、大穗结缕草 (Z .macrostachyaFranch .)和长花结缕草 (Z .sinicavar.nipponicaOhwi)为一组 ,另有两组为比较独特的类型。结缕草属植物叶表面被毛、叶长、叶宽等营养性状和生殖枝高度、小穗密度、小穗数量等生殖性状都有较大的变异 ,变异系数 13.75 %～ 5 8.74 % ,其中中华结缕草内部存在更大的变异 ,表明在中华结缕草种内选育更加容易获得优良种质或品种。主成分分析表明 ,小穗数、小穗长、小穗密度、小穗长宽比以及叶片宽度和叶片被毛发达情况是结缕草属形态分类的重要依据 ,其中叶片被毛发达情况可以作为区分结缕草和中华结缕草的简单依据 ;而生殖枝高度、穗长、叶长、花序柄长度 (1)和叶长宽比可作为研究结缕草属下种内分异的主要依据     

时空表达可控的转基因动物模型调控体系的研究

目的在血管内皮细胞建立时空表达可控的转基因动物模型调控体系。方法培育两个配套的转基因动物品系,利用组织专一性启动子确保转基因表达的空间专一性,利用四环素诱导系统对转基因表达在时间上实施调控。结果将血管内皮细胞特异性表达的VE cadherin基因启动子与人工融合的转录因子tTA基因连接,建立转基因小鼠品系VE cadherin:tTA;将tetoperon的启动子与myrAkt1连接,建立转基因小鼠品系TET:myrAkt1。两系鼠杂交的子代,筛选的阳性纯合子,能可控性地在血管内皮细胞特异性表达目的基因Akt1PKB。结论利用VE cadherin基因启动子和tet off诱导表达系统,可以达到在时间上和空间上都能人为控制目的基因在血管内皮细胞上特异性表达的目的。     

Kinetics of aflatoxin biosynthesis by Aspergillus parasiticus in the presence of N(alpha)-palmitoyl-L-lysyl-L-lysine-ethyl ester dihydrochloride or dichlorvos

N(alpha)-Palmitoyl-L-lysyl-L-lysine-ethyl ester dihydrochloride (PLL) has antimicrobial properties and may be useful as a food preservative. This study was conducted to see if PLL can inhibit growth and synthesis of aflatoxin by Aspergillus parasiticus. Growth of mold and accumulation of aflatoxins were monitored for up to 15 days. To compare these data with those of a known inhibitor of aflatoxin synthesis, dichlorvos was added to media, and mold growth and aflatoxin accumulation were monitored. The kinetic model of Brown and Vass that correlates growth and formation of secondary metabolites was applied to results of this study, and values for maturation time (t(m)) and aflatoxin accumulation rate constant (alpha) were calculated. Values of t(m) decreased when cultures contained PLL, whereas presence of dichlorvos resulted in a considerable increase. The lag phase of mold growth increased in the presence of PLL. The values of alpha increased with an increasing amount (up to 300 ppm) of PLL in media. Higher concentrations of PLL decreased the value of alpha. All levels of dichlorvos tested decreased the value of alpha. The aflatoxin accumulation rate constant (alpha) as a function of concentration of additive (C) followed the general equation: \documentclass{article}\pagestyle{empty}\begin{document}$$\alpha = \frac{{\alpha _m C\exp (- {C \mathord{\left/ {\vphantom {C {K_i }}} \right. \kern-\nulldelimiterspace} {K_i }})}}{{C + K_a }}$$\end{document} where alpha(m), K(a), and K(i) are constants.     

The threshold of perception of angular acceleration as a function of duration

The threshold for rotation about the yaw axis was determined for constant acceleration stimuli as a function of their duration in the range from 3 to 25 s. From the torsion-swing model the following theoretical equation can be derived: 1 $$a_{{\text{thr}}} = {C \mathord{\left/ {\vphantom {C {\left[ {1 - \exp \left( { - {{t_s } \mathord{\left/ {\vphantom {{t_s } {\tau _1 }}} \right. \kern-\nulldelimiterspace} {\tau _1 }}} \right)} \right]}}} \right. \kern-\nulldelimiterspace} {\left[ {1 - \exp \left( { - {{t_s } \mathord{\left/ {\vphantom {{t_s } {\tau _1 }}} \right. \kern-\nulldelimiterspace} {\tau _1 }}} \right)} \right]}}$$ , where a _thr=acceleration amplitude at threshold, t _s =duration of the acceleration, τ₁=time constant, C=threshold for very long stimuli. According to this formula the Mulder product (i.e. the product of the threshold acceleration amplitude and the duration of the stimulus) is constant for durations up to 0.3 τ₁. The best fit of this theoretical function to the somatosensory data is found for τ₁=14.5 s, and C=0.22⁰/s ². The time within the Mulder product is constant (about 5s) is doubtless due to the mechanics of the semicircular canals. For the oculogyral data a lower value of τ₁ is found. We do not have any explanation for this lower value.     

Generalization of monod kinetics for analysis of growth data with substrate inhibition

The inhibitory effect of butanol on yeast growth has been studied for the strain Candida utilis ATCC 8205 growing aerobically on butanol under batch conditions. A mathematical expression was then proposed to fit the kinetic pattern of butanol inhibition on the specific growth rate: \documentclass{article}\pagestyle{empty}\begin{document}$$ \mu = \frac{{\mu _m S}}{{K_s + S}}\left[{1 - \frac{S}{{S_m }}} \right];n $$\end{document}The maximum allowable butanol concentration above which cells do not grow was predicted to be 9.16g/L. The proposed model appears to accurately represent the experimental data obtained in this study and the literature data developed for a variety of batch culture systems at widely ranging substrate concentrations.     

Prolonged activation of tumor necrosis factor (TNF)-alpha and its soluble receptors in chronic heart failure patients both in the compensated and decompensated state. Interplay between their levels and metalloproteinase-3

INTRODUCTION: Recent clinical and experimental studies indicate that upregulation of the TNF system can contribute to the progression of cardiac remodeling and heart failure decompensation, by promoting alterations in cardiomyocyte biology and extracellular matrix metabolism. Extracellular matrix turnover is regulated by the matrix metalloproteinases (MMPs), which are endogenous enzymes responsible for extracellular collagen degradation. The present study investigates the fluctuation of serum levels of TNF-alpha, soluble TNF receptor-1 (sTNFR1) and -2 (sTNFR2), in patients with chronic heart failure both during acute decompensation and the stable state of the syndrome. The second goal of this study was to determine if a relationship exists between serum MMPs profiles (MMP-1, MMP-2, MMP-3) and circulating TNF-alpha or its soluble receptors. METHODS: Our patient group consisted of 52 patients with chronic heart failure (NYHA III-IV; mean age: 65 +/- 4 years; hypertensive cardiomyopathy: 20, ischemic cardiomyopathy: 17, dilated cardiomyopathy: 10, valvular disease: 5), who were hospitalized for acute decompensation of the syndrome. Our control group consisted of 30 healthy subjects (mean age: 57 +/- 6 years). Serum levels of TNF-alpha, sTNFR1, sTNFR2 and MMP-1,-2,-3 were measured in heart failure patients by ELISA at admission and after one month as follow-up. Values are expressed as medians and interquartile ranges. RESULTS: In our patient group, we observed a statistically significant increase in the levels of sTNFR1 and sTNFR2 at admission (sTNFR1: 5.15 ng\mL, 4.49-8.90 ng\mL, P < 0.001, sTNFR2: 13.40 ng\mL, 6.10-21.50 ng\mL, P < 0.001), and at one-month follow-up (sTNFR1: 5.30 ng\mL, 4.61-6.90 ng\mL, P < 0.001, sTNFR2: 21.80 ng\mL, 11.50-25.20 ng\mL, P < 0.001), compared to the control group (sTNFR1: 3.83 ng\mL, 3.70-3.95 ng\mL, sTNFR2: 4.00 ng\mL, 3.40-5.40 ng\mL). There was a statistically significant difference in the levels of sTNFR2 between admission and follow-up (P < 0.05). Significant correlations between serum MMP-3 and sTNFR2 levels both at admission and follow up (r -/+ 0.460, P -/+ 0.005 and r -/+ 0.338, P -/+ 0.044, respectively) were also found. CONCLUSIONS: Soluble TNF receptors are elevated in heart failure patients both in acute decompensation and stable phase. We have detected higher levels of soluble TNFR2 during the compensated phase of heart failure, suggesting that TNFR2 receptors appear to stabilize the cytokine and thereby prolong its half-life and biological functions. Finally, TNF system-mediated cardiac remodeling may exist through the activation of MMP-3 signaling pathways.     

The Tryptophan Fluorescence of Tetracarbidium conophorum Agglutinin II and a Solution-Based Assay for the Binding of a Biantennary Glycopeptide

The plant lectin Tetracarbidium conophorum agglutinin II binds to glycoproteins and glycopeptides in a structurally specific manner [Animashaun et al., (1994) Glycoconjugate J. 11, 299–303]. We have characterized the steady-state and time-resolved fluorescence of the tryptophan residues of this lectin. The fluorescence (λ_ex = 295 nm, λ_em = 350 nm) decay is complex and can be described by four decay times with the following values: τ₁ = 7.4nsec, α₁ = 0.22; τ₂ = 2.9 nsec, α₂ = 0.25; τ₃ = l.0 nsec, α₃ = 0.34; τ₄ = 0.2 nsec, α₄ = 0.18. The addition of a biantennary glycopeptide $\begin{array}{*{20}c} {Gal\beta (1 \to 4)GlcNAc\beta (1 \to 2)Man\alpha (1 \to 6)\neg } \\ {Man\beta (1 \to 4)GlcNAC\beta (1 \to 4)GlcAc\beta (1 \to )\begin{array}{*{20}c} {Glu - Nh_2 } \\ | \\ {Asn} \\ | \\ {COOH} \\ \end{array} } \\ {Gal\beta (1 \to 4)GlcNAc\beta (1 \to 2)Man\alpha (1 \to 3)} \\ \end{array} $ to the lectin results in a quench and an 8 nm blue shift of the emission spectrum. The effect is saturable, and is described by an association constant of 1.8×10⁵ M^?1. The tryptophan fluorescence of Tetracarbidium conophorum agglutinin II may therefore be utilized to characterize thermodynamically the binding interactions between this lectin and complex glycoprotein.     

Transient method for proposing the mechanisms of reactions over immobilized enzymes

The transient response method is introduced to elucidate the mechanism of reaction over immobilized enzyme. Glucose oxidation over the glucose oxidase that was immobilized on ion-exchange resin using glutaraldehyde as a linking agent is selected as an example here. The transient responses of a fixed-bed reactor to step increases and decreases in glucose, oxygen, and gluconolactone feed concentrations have been monitored and interpreted. From some responses, we have found that gluconolactone is formed in the reaction of glucose with adsorbed oxygen, while hydrogen peroxide is formed in the reaction of oxygen with adsorbed glucose. Combining all information from interpreting the responses with the literature, a mechanistic picture can be obtained as follows: \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {E_{{\rm ox}} + G \to E_{{\rm red}} GL} \\ {E_{{\rm red}} GL \to E_{{\rm red}} + GL} \\ {E_{{\rm red}} + {\rm O}_2 \to E_{{\rm ox}} {\rm H}_2 {\rm O}_2 } \\ {E_{{\rm ox}} {\rm H}_2 {\rm O}_2 \to E_{{\rm ox}} + {\rm H}_2 {\rm O}_2 } \\ \end{array} $$\end{document}.