单甲基化表没食子儿茶素没食子酸酯的化学合成

表没食子儿茶素没食子酸酯(EGCG)经甲基化后在抗过敏、降血脂等方面具有更高的生物活性。但茶叶中甲基化EGCG含量较低,为进一步研究其生物活性,本文对其半合成路线进行了优化。先以EGCG为原料制得五苄基化的表没食子儿茶素(EGC),然后将没食子酸丙酯经4-甲氧基苯甲醛二甲缩醛保护,甲基化,脱保护,苄基化,水解得到3,4-二苄氧基-5-甲氧基苯甲酸,再与苄基化EGC酯化和脱苄基得到表没食子儿茶素3-O-甲基没食子酸酯(3″-Me-EGCG);同样将没食子酸丙酯经全乙酰化、选择性甲基化、脱除乙酰基、苄基化、水解得到3,5-二苄氧基-4-甲氧基苯甲酸,再与苄基化EGC酯化和脱苄基得到表没食子儿茶素4-O-甲基没食子酸酯(4″-Me-EGCG);总产率分别为53%和57%。     

全甲基化没食子儿茶素没食子酸酯的制备

通过对价格昂贵的没食子儿茶素没食子酸酯(-)-GCG进行一步甲基化制备全甲基化(-)-GCG成本较高,所以本文选取对绿茶粗提物进行乙酰化和甲基化2种方法来制备全甲基化(-)-GCG,其中甲基化方法产率达到7.6%,是获得全甲基化(-)-GCG较简单经济的途径,为(-)-GCG的衍生化修饰及其MDR逆转活性的研究提供基础,所合成的化合物均经核磁共振氢谱、碳谱、质谱以及旋光对其结构进行了验证。     

四种齐墩果酸皂苷的合成

为获得高活性齐墩果酸皂苷药物候选分子，报道了4种单糖(葡萄糖、半乳糖、木糖、阿拉伯糖)与齐墩果酸的D3羟基进行糖苷化反应合成皂苷的方法。在合成中采用糖的全苯甲酰化三氯乙酰亚胺酯为糖基供体，齐墩果酸烯丙醇酯为糖基受体，在三氟甲磺酸三甲基硅醇酯(TMSOTf)的作用下，糖基供体与齐墩果酸的C-3羟基进行糖苷化，以较高的收率和专一的立体选择性得到4种齐墩果酸单糖皂苷。化合物结构经核磁共振波谱得以确证。     

薯蓣皂苷的汇聚式合成

采用汇聚式合成策略高效完成了天然产物薯蓣皂苷的合成。在PhCF_3/~t BuCN/CH_2Cl_2溶剂中,以HB(C_6F_5)_4作为催化剂,-20℃条件下马铃薯三糖三氯亚胺酯供体与薯蓣皂苷元反应,以β/α=11.8/1的立体选择性和97%的产率得到糖苷化产物,然后脱除保护基得到薯蓣皂苷。     

高黏度聚丙烯酸增稠剂的合成及表征

以丙烯酸为原料、季戊四醇三烯丙基醚(APE)为交联剂,乙酸乙酯和正己烷为混合溶剂,采用沉淀聚合法合成丙烯酸(AA)-甲基丙烯酸十八酯(SMA)接枝共聚物,并采用红外光谱(FT-IR)、核磁(1H-NMR)、扫描电镜(SEM)等方法进行表征。结果表明:合成的聚丙烯酸为具有三维网状结构的交联聚合物,重均分子量(Mw):8.931×109;分子量分布(Mz/Mn):1.678;产物有较好的透光度和黏度,在pH=6~8间,0.5%w(PAA)的透光率为95.1%,黏度最高可达1938 Pa.s。     

常山酮的合成方法研究

本文对常山酮(halofuginone)的合成方法进行了研究和改进,以2-甲基-3-羟基吡啶为起始原料,其甲基化产物与乙腈加成后经Rh/Al2O3选择性还原得(3-甲氧基-2-哌啶基)-丙酮,再经溴代、N-保护后与6-氯-7-溴-4(3H)-喹唑啉酮偶联,产物经水解脱保护得目标化合物6-氯-7-溴-3-(3-(3-羟基-2-哌啶基)-丙酮基)-4(3H)-喹唑啉酮氢溴酸盐,通过6步反应制得了常山酮,总收率为11.6%,为常山酮的工业化生产提供了可能。目标产物和各步中间体结构经MS1、H NMR和13CNMR确证。     

Liquid freshwater transport and Polar Surface Water characteristics in the East Greenland Current during the AO-02 Oden expedition

Dynamical features of the East Greenland Current (EGC) are synthesized from a survey conducted by the Swedish icebreaker Oden during the International Arctic Ocean - 02 expedition (AO-02) in May 2002 with emphasis on the liquid freshwater transport and Polar Surface Water. The data include hydrography and lowered acoustic doppler current profiler (LADCP) velocities in eight transects along the EGC, from the Fram Strait in the north to the Denmark Strait in the south. The survey reveals a strong confinement of the low-salinity polar water in the EGC to the continental slope/shelf—a feature of relevance for the stability of the thermohaline circulation in the Arctic Mediterranean. The southward transport of liquid freshwater in the EGC was found to vary considerably between the sections, ranging between 0.01 and 0.1 Sverdrup. Computations based on geostrophic as well as LADCP velocities give a section-averaged southward freshwater transport of 0.06 Sverdrup in the EGC during May 2002. Furthermore, Oden data suggest that the liquid freshwater transport was as large north of the Fram Strait as it was south of the Denmark Strait.     

The East Greenland Coastal Current: Structure, variability, and forcing

The subtidal circulation of the southeast Greenland shelf is described using a set of high-resolution hydrographic and velocity transects occupied in summer 2004. The main feature is the East Greenland Coastal Current (EGCC), a low-salinity, high-velocity jet with a wedge-shaped hydrographic structure characteristic of other surface buoyancy-driven currents. The EGCC was observed along the entire Greenland shelf south of Denmark Strait, while the transect north of the strait showed only a weak shelf flow. This observation, in conjunction with water mass considerations and other supporting evidence, suggests that the EGCC is an inner branch of the East Greenland Current (EGC) that forms south of Denmark Strait. It is argued that bathymetric steering is the most likely reason why the EGC apparently bifurcates at this location. Repeat sections occupied at Cape Farewell between 1997 and 2004 show that the alongshelf wind stress can have an influence on the structure and strength of the EGCC and EGC on timescales of 2-3 days. Accounting for the wind-induced effects, the volume transport of the combined EGCC/EGC system is roughly constant (∼2 Sv) over the study domain, from 68°N to Cape Farewell near 60°N. The corresponding freshwater transport increases by roughly 60% over this distance (59-96 mSv, referenced to a salinity of 34.8). This trend is consistent with a simple freshwater budget of the EGCC/EGC system that accounts for meltwater runoff, melting sea-ice and icebergs, and net precipitation minus evaporation.     

An inverse modeling study in Fram Strait. Part I: dynamics and circulation

In order to reconstruct the circulation in the northern Greenland Sea, between 77°N and 81°N, and the exchanges with the Arctic Ocean through Fram Strait, a variational inverse model is applied to the density field observed in summer 1984 during the MIZEX 84 experiment. An estimate of the three-dimensional large-scale pressure field is obtained in which the solution is decomposed into a limited number of vertical modes and the mode amplitudes are described by piece-wise polynomials on a finite-element grid. The solution should be consistent with a frictional depth-integrated vorticity balance and with the density data. The global model parameters are tuned to ensure agreement between the retrieved geostrophic velocity and independent currentmeter data. In a companion paper (Schlichtholz and Houssais, 1999b), the same method, but without dynamical constraint, is applied to the same hydrographic dataset to perform a detailed water mass analysis and to estimate individual water mass transports.A comprehensive picture of the summer geostrophic circulation in Fram Strait is obtained in which northward recirculations in the East Greenland Current (EGC) and various recirculations from the West Spitsbergen Current (WSC) to the EGC are identified. It is suggested that the branch of the WSC following the upper western slope of the Yermak Plateau turns westward beyond 81°N and recirculates southward along the lower slope, then merging with a westward recirculating branch south of 79°N. At 79°N, a southward net transport of 6.5 Sv is found in the EGC which, combined with a northward net transport of only 1.5 Sv in the WSC, results in a fairly large outflow of 5 Sv from the Arctic Ocean to the Greenland Sea.The inverse solutions show that, in summer, the local induction of vorticity by the wind stress curl or by meridional advection of planetary vorticity should be small, so that, in the EGC and in the WSC, the vorticity balance is mainly achieved between the bottom pressure torque and dissipation of vorticity through bottom friction. A substantial barotropic flow associated with along-slope potential energy gradients is indeed identified on both sides of the strait.     

中-晚全新世冷水团对西格陵兰Disko湾的影响

西格陵兰位于北极—北大西洋地区,其海洋环境演变受西格陵兰洋流中冷、暖水团的显著影响。本文运用主成分分析方法对西格陵兰Disko湾DA06-139G孔沉积物中主要硅藻属种进行研究,试图揭示5000a BP以来西格陵兰洋流中冷、暖水团强度变化对研究区海洋环境的影响。5000—3800a BP期间,东格陵兰寒流携带的极地冷水团强度较弱,而北大西洋暖水团势力较强,Disko湾地区海洋环境较为温暖。3800—2000a BP期间,西格陵兰洋流中极地冷水团势力呈现阶段性增强,此时Disko湾地区气候缓慢转冷,海冰覆盖面积逐渐增加。2000a BP以后,特别是650a BP之后,样品在主成分轴一上的得分显著增高,表明Disko湾气候明显变冷,来自东格陵兰寒流的极地冷水团强度显著增强。Disko湾中晚全新世以来的硅藻记录及样品在主成分轴一上的得分所指示的极地冷水团的强度变化与格陵兰冰芯温度及海冰变化等具有较好的一致性,说明研究区海流特征与大气温度、海冰等环境要素密切相关。     

栉孔扇贝壳尺寸性状对活体重的影响效果分析

选取 65只 2岁龄栉孔扇贝 ,测定其壳长、壳厚、壳高、活体重、肉重、熟肉重 ,计算相关系数 ,采用通径分析方法计算了以贝壳性状为自变量对活体重作依变量的通径系数、决定系数及相关指数。结果表明 ,栉孔扇贝壳长、壳厚、壳高与活体重、净肉重、熟肉重的相关系数均达到极显著水平 (P <0 .0 1 ) ;壳高对活体重的直接影响 ( 0 .6682 )最大 ,是影响活体重的主要因素 ;壳长与活体重的相关程度很大 ,但对活体重的直接影响 ( 0 .2 5 5 9 )较小 ,主要通过壳高间接影响活体重 ,是影响活体重的次要因素 ;壳厚对活体重的直接影响 ( 0 .0 960 )最小 ;决定系数分析结果与通径分析结果有一致的变化趋势 ;所选贝壳性状与活体重的复相关指数为R2 =0 .8847;多元回归分析建立了壳长、壳厚、壳高估计活体重的回归方程为 :^Y =- 42 .1 331 + 3.1 60X1 + 3.5 2 5 3X2 + 7.692 0X3,为扇贝选种提供了理论依据和理想的测度指标。     

Development of EST-SSR primers and their practicability test for Laminaria

Laminaria (Saccharina) is one of the economic important seaweeds.Through sequence analysis of 4 099 ESTs from Laminaria (971 were generated from our own cDNA laboratories and 3 128 were downloaded from updated EST databases) with SSRIT software,two hundred and fifty-four SSRs in 206 ESTs were found.From the 254 SSRs,sixty-three SSR primer-pairs were designed. In order to test their practicability, the 63 primer-pairs were tested in commonly used SSR reaction conditions using 12 Laminara DNA samples as templates. The results show that 23 SSR primer-pairs gave good amplification patterns on most (more than 80%) of the 12 Laminara DNA templates. Genetic diversity study of 12 Laminaria lines,which were widely used in breeding and economic cultivation in China,was performed based on the obtained SSR data.     

White-light promoted degradation of leucopterin and related pteridines dissolved in seawater, with evidence for involvement of complexation from major divalent cations of seawater

The photochemical instability of several related pteridines in seawater was investigated by aseptic incubation of solutions at 20–22°C under illumination from cool-white light of intensity 6 kerg cm⁻² sec⁻¹, and the chemical changes were spectrophotometrically monitored. All the pteridines showed markedly accelerated degradation from this illumination relative to their behaviour in total darkness.Pterin and lumazine were degraded very slowly with zero-order reaction kinetics, while the other pteridines photolysed rapidly (according to first-order kinetics) with decomposition rates increasing in the order dioxylumazine (2,4,6,7-tetrahydroxypteridine) < leucopterin < isoxanthopterin < xanthopterin < oxylumazine (2,4,6-trihydroxypteridine). Excepting leucopterin and dioxylumazine, the photolysis rates were attributable to the pH of seawater and not its salt content; this was also the case with oxylumazine which required the salt content of seawater for decomposition in darkness. Leucopterin and dioxylumazine (both 6,7-dihydroxylated pteridines) gave evidence of complexation with the major divalent cations (Ca²⁺, Mg²⁺) of seawater, by virtue of which their photolytic degradation rates were enhanced to magnitudes obtained in pH-10 buffer without seawater. It is proposed that such complexation produces structural forms of these pteridines analogous to their normal ionic forms at pH 10–12.The photolysis of the 6-hydroxylated pteridines (xanthopterin, oxylumazine) proceeded via intermediate formation of their corresponding 7-hydroxylated derivatives (leucopterin, dioxylumazine).     

亚临界流体中酶催化制备富含多不饱和脂肪酸甘油酯

研究亚临界流体中酶催化制备富含多不饱和脂肪酸甘油酯.采用亚临界R134a作为固定化脂肪酶Nonozym435催化富含n-3多不饱和脂肪酸甘油酯合成的反应介质,并利用响应面法对影响甘油酯合成的工艺条件进行了优化.结果表明,反应时间、酶用量、底物摩尔比、初始水分是影响酯化率的显著因素.通过对转化率的拟合模型响应面分析,得到了优化工艺条件:在亚临界R134a体系中,体系压力4 MPa,温度40 ℃,反应时间3.59 h,酶量:底物量的3.44%,底物摩尔比质量分数为4.55∶1(甘油/游离脂肪酸),初始水分含量0.81%;在此优化工艺条件下,酯化率的预测值为78.89%,试验值为84.06%.试验值与预测值的相符性很好,RSM模型的有效性得到验证.     

A simple method for the detection of hepatitis A virus in the environmental samples by polymerase chain reaction

Hepatitis A virus (HAV) is very persistent in the environment and is especially difficult to detect in the seafoods. In recent years, molecular cloning of the genome of HAV has led to sensitive polymerase chain reaction (PCR) method for the detection of HAV RNA. Here we describe a new and simple procedure to extract RNA from contaminated clams and the PCR method for detection of HAV in environmental samples. The specificity and efficiency of PCR amplification were studied using cDNA and RNA of HAV. Three primer couples gave satisfactory results. Some basic parameters of the PCR were modified to perform a highly specific and sensitive test.     

Anthropogenic carbon in the East Greenland Current

Sections of dissolved inorganic anthropogenic carbon () based on 2002 data in the East Greenland Current (EGC) are presented. The has been estimated using a model based on optimum multiparameter analysis with predefined source water types. Values of have been assigned to the source water types through age estimations based on the transit time distribution (TTD) technique. The validity of this approach is discussed and compared to other methods. The results indicated that the EGC had rather high levels of in the whole water column, and the anthropogenic signal of the different source areas were detected along the southward transit. We estimated an annual transport of with the Denmark Strait overflow (σ_θ > 27.8 kg m⁻³) of ∼0.036 ± 0.005 Gt C y⁻¹. The mean concentration in this density range was ∼30 μmol kg⁻¹. The main contribution was from Atlantic derived waters, the Polar Intermediate Water and the Greenland Sea Arctic Intermediate Water.