ORGANIC-PHASE ENZYME ELECTRODE OPERATED IN WATER-FREE SOLVENTS

A new material, polyhydroxyl cellulose, and a refrigerating immobilization method were used to construct HRP-mediator electrode for determination of hydrogen peroxide in water-free organic solvents. Rapid and sensitive response was obtained. The enzyme el

A STUDY ON POLYMER-POLYMER INTERACTIONS THROUGH MIXING CALORIMETRY

The aim of this work is to describe the most recent achievements in the field of the physical chemistry of mixing. The systems studied have been classified according to the amount of thermic effect due to the blending and its interpretation. When polystyrene (PS) and poly(alpha-methylstyrene) (P alpha MS) are blended, the interaction is weak and Delta(mix)H is close to zero. The presence of polar atoms and/or groups increases the stability of the blend and, therefore, Delta(mix)H becomes more negative. Poly(ethylene oxide) (PEO), poly(methyl acrylate) (PMA), poly(methyl methacrylate) (PMMA) and poly(vinylacetate) (PVAc), when mixed to form binary systems, show large differences from their properties when pure. If hydrogen bonding takes place, the interactions are readily detected and a large effect is calorimetrically determined. Cellulose diacetate (CDA) and poly(vinylpyrrolidone) (PVP) have been studied as an example of a strongly interacting system.

SURFACE-MODIFIED HYDROPHILIC MEMBRANES IN MEMBRANE DISTILLATION

The porosity and the hydrophobicity of membranes are two essential requirements for membrane distillation (MD) of aqueous solutions. So far, the hydrophobic porous membranes used in MD studies have been prepared from hydrophobic materials. In this work, hydrophilic cellulose acetate and cellulose nitrate membranes were modified into hydrophobic membranes by radiation grafting polymerization and plasma polymerization, and used in MD studies successfully. The results indicated that modified membranes with good performance in MD can be obtained if the modifying conditions are controlled appropriately. Especially plasma polymerization, in which many particular kinds of monomer could be polymerized onto the surface of porous materials, has become an efficient method to prepare hydrophobic porous membrane with high performance from hydrophilic membranes. It will stimulate the development and practical application of MD.

PLASMA POLYMERIZATION OF OCTAFLUOROCYCLOBUTANE AND HYDROPHOBIC MICROPOROUS COMPOSITE MEMBRANES FOR MEMBRANE DISTILLATION

In this paper, hydrophilic microporous cellulose nitrate membranes have been surface-modified by plasma polymerization of octafluorocyclobutane (OFCB). The microporous composite membranes with a hydrophilic layer sandwiched between two hydrophobic layers have been obtained. The obtained composite membranes have been used in a membrane distillation (MD) process and have exhibited good performance. The effects of polymerization conditions, such as glow-discharge power and deposition time, on the structures and MD performances of the obtained composite membranes have been investigated by SEM, X-ray microscopical analysis, and XPS. The polymerization conditions should be as mild as possible in order to prepare the hydrophobic composite membrane with good MD performance. The typical MD behaviors of the obtained hydrophobic composite membranes are in agreement with that of hydrophobic membranes directly prepared from hydrophobic polymeric materials, like PVDF, PTFE, or PP.

Purification and partial characterization of Mn superoxide dismutase from muscle tissue of the shrimp Macrobrachium nipponense

Superoxide dismutase (SOD; EC 1.15.1.1) is an enzyme that protects against oxidative stress from superoxide radicals in living cells. This enzyme had been isolated, purified and partially characterized from muscle tissue of the shrimp Macrobrachium nipponense. The purification was achieved by heat treatment, ammonium sulfate fractionated precipitation and column chromatograph on DEAE-cellulose 32. Some physiological and biochemical characterization of it was tested. The molecular weight of it was about 21.7 kDa, as judged by SDS-polyacrylamide gel electrophoresis. The purified enzyme had an absorption peak of 278 nm in ultraviolet region, and the enzyme remained stable at 25-45 degreesC within 90 min. However, it was rapidly inactivated at higher temperature. Treatment of the enzyme with 1 mM ZnCl2, SDS and 1 mM or 10 mM mercaptoethanol showed some increasing activity. However, the enzyme activity was obviously inhibited by 10 mM CaCl2, CuSO4, ZnCl2 and 1 mM CaCl2 and 10 mM K2Cr2O7. SOD activity did not show significantly variation after incubated with 1 mM CaCl2, EDTA and 10 MM SDS. The enzyme was insensitive to cyanide and contained 1.03 +/- 0.14 atoms of manganese per subunit shown in atomic absorption spectroscopy, which revealed that purified SOD was Mn superoxide dismutase. (C) 2004 Elsevier B.V. All rights reserved.

An acidic polysaccharide with xylose branches from Porphyra yezoensis

An acidic polysaccharide (PY3) was isolated from the hot water extract of the red algae Porphyra yezoensis by successive column chromatographies over DEAE-cellulose and Sephadex G-200. PY3 with an average molecular weight of 1.8x10(5) was demonstrated to be composed of galactose (Gal), 3,6-anhydrogalactose (3,6-AnGal), 6-OSO3-galactose (6-OSO3-Gal) and xylose (Xyl) in an approximate molar ratio of 25 : 15, 10, 1. In view of Smith degradation and methylation and on the basis of spectral evidence including those of IR, GC, GC-MS, and H-1 and C-13 NMR, the most probable repeating unit of PY3 could be proposed as [(1-->3)beta -D-Gal(1 --> 4)alpha -L-3,6-AnGal](3)-[(1 --> 3)beta -D-Gal(1 --> 4)alpha -L-6-OSO3-Gal](2) with a xylose moiety at the C-6 of one of every twenty-five beta -D-Gal residues. To our knowledge, PY3 was shown to be the first porphyran possessing occasional xylose branches.

Chemical species of iodine in some seaweeds II. Iodine-bound biological macromolecules

The distribution of iodine in various biological macromolecules in Sargassum kjellmanianum was studied using neutron activation analysis combined with chemical and biochemical separation techniques. The results indicate that iodine is mainly bound with protein, part of iodine with pigment and polyphenol, and little with polysaccharides, such as algin, fucoidan and cellulose. This result is significant for the mechanism of enriching iodine of algae and utilization of alga iodine.

Study on early-stage development of conchospore in Porphyra yezoensis Ueda

Porphyra yezoensis Ueda (Rhodophyta) is a seaweed of economic importance with a typical dimorphic life cycle consisting of a leafy gametophyte and a filamentous sporophyte. Recently, it has been recognized as a model system for fundamental and applied studies in marine biological sciences. Conchospore, a major spore linking the two distinct multicellular phases in the life cycle, is most widely used in the breeding of P. yezoensis. In this paper, the early-stage development of conchospore, including the attachment and the cell wall formation, was studied with fluorescent reagents staining and Scanning Electron Microscopy detection. Results displayed: (I) the cell wall began to be generated after culturing for 4 h in the attached conchospores; (2) the initially released conchospores were plastids with some filmy, amorphous substance on the surface, and they attached to the fibers firmly via the actively secreted mucilaginous substances after their touch to the fibers; (3) cellulase and pectolase prohibited the attachment of conchospores in the different ways; and (4) only attached conchospores generated cell walls and developed normally, while the suspending ones could not. It indicated that the cellulose played crucial roles in the permanent attachment as the pectin did in the initial attachment. The conchospore attachment seemed to trigger the cell wall formation and the further development. Affects of light on the development of conchospores were also discussed. The results showed that high intensity (200 mu mol.m(-2).s(-1)) and long-wave (>= 580 nm) light facilitated the division rate of conchospores. (C) 2008 Elsevier B.V. All rights reserved.

琼脂分级产物的研究

琼脂（agar，又称琼胶）作为世界三大工业海藻胶之一，被广泛应用于食品、医药、生物技术、造纸等领域。本文首先研究了琼脂的分级方法，用DEAE-Cellulose将石花菜琼脂分级，得到四个级分，即水级分、0.5mol/L NaCl级分、1.0mol/L NaCl级分、2.5mol/L NaCl级分。分析了各级分的理化性质，并通过IR和~（13）C-NMR光谱研究其化学结构。石花菜琼脂分级得到的四个级分中，水级分的硫酸基含量为0.16%，凝胶强度为1130 g/cm~2（1%浓度），电内渗（EEO）为0.12，主要质量标准为Sigma公司的低电内渗琼脂糖(agarose）产品接近，符合低电内渗琼脂糖产品的质量要求。1.0mol/L NaCl级分和2.5mol/L NaCl级分的硫酸基含量较高，分别为22.8%和32.5%，合称为硫琼脂(agaropectin）。在琼脂糖的应用中，特别是现代生物技术研究中，需要低凝固温度琼脂糖。本文以石花菜琼脂分级得到的水级分为原料，采用甲基化反应制备低凝固温度琼脂糖。实验产品的凝固温度为30.1 ℃(1.5%浓度），融化温度为64.8 ℃（1.5%浓度），凝胶强度为264 g/cm~2(1%浓度），主要质量标准与Sigma公司的低凝固温度琼脂糖产品接近，符合低凝固温度琼脂糖产品的质量要求。随着对多糖生物学功能的深入，海藻硫酸多糖表现出多种生物活性，其活性研究已经成为目前新药研究的一个热点。到目前为止，有关琼脂分级产物的生物活性研究较少。本文在研究石菜硫琼脂的组成和主要理化特性的基础上，对基体内外抗凝血活性进行了较系统的研究。新西兰兔腹主动脉血体外抗凝实验结果表明，石花菜硫琼脂具有明显的体外抗凝血活性，在3.125mg/ml ～ 25mg/ml剂量范围内呈现量效关系；大鼠体内抗凝血实验的结果表明其口服可以吸收，在体内产生抗凝血作用，在100 mg/kg·d ～ 400 mg/kg·d剂量范围内，与全血凝血时间(CT）、凝血酶时间（TT）、凝血酶原时间（PT）、部分凝血活酶时间（KPTT）的延长及血浆纤维蛋白原（Fib）含量的降低均呈剂量依赖关系。就其抗凝血机制而言，石花菜硫琼脂的抗凝血作用既影响凝血系统，又影响纤溶系统。

紫菜壳孢子萌发过程及其世代差异研究

紫菜是一类海洋藻类研究的模式系统，具有重要的经济价值和理论研究意义。本研究基于紫菜的世代交替生活史，对其壳孢子萌发过程进行了研究，并对丝状孢子体与叶状配子体的世代差异进行了分析，主要包括以下三部分： 1） 对紫菜丝状孢子体与叶状配子体的连接枢纽——壳孢子的发育过程及其光影响进行了研究与讨论，发现壳孢子只有在附着后才能形成细胞壁并发育，说明壳孢子的附着是触发了壳孢子细胞壁的形成以及后期发育的开关，亦即附着是触发紫菜世代交替过程中配子体转录组表达的开关；纤维素酶和果胶酶均能抑制壳孢子附着，但影响机制各不相同，推测果胶质主要介导壳孢子的初始附着，而纤维素则与永久附着相关；波长≥580 nm的高强度（200 μmol•m-2•s-1）可见光有利于壳孢子早期发育。 2） 结合现有藻类数据，对坛紫菜丝状孢子体阶段11000 EST数据进行了大规模的生物信息学分析，结果首次发现坛紫菜丝状孢子体中可能存在PCK型C4光合固碳途径，并筛选出44条在紫菜孢子体中表达上调的代表基因。 3） 结合坛紫菜、条斑紫菜、海带和红毛菜，对红藻和褐藻等大型海藻孢子体与配子体阶段代表基因Rubisco的表达与羧化酶活性差异进行了研究分析，结果表明Rubisco的表达量和初始羧化酶活在其配子体中均显著高于其孢子体世代，即与藻体不同世代的相对复杂度无关，而与染色体倍性相关，说明Rubisco的世代差异极有可能与染色体倍性相连锁，因而可能是海藻世代交替过程中的重要功能基因。

Study on extraction of agaropectin from Gelidium amansii and its anticoagulant activity

Gelidium amansii agar was fractionated on DEAE-cellulose and four fractions were obtained sequentially. The yields of 1.0 mol/L NaCl fraction and 2.5 mol/L NaCl fraction were 2.80% and 2.03%. They are highly sulfated agar, and named as agaropectin with sulfate content being 22.8% and 32.5%, respectively. The anticoagulant experiment results show that agaropectin could effectively prolong the coagulation time in a dose-dependent manner in vitro. Agaropection could be absorbed and effectively prolong the plasma coagulation time in vivo. After intragastric administration at the doses of 100, 200, and 400 mg/kg.d in rats for 15 days, TT (thrombin time), CT (coagulation time), PT (prothrombin time), and APTT (activated partial thromboplastin time) could be effectively prolonged and the plasma Fib level could be significantly lowered.

中国中部全新世气候变化的泥炭同位素记录--以湖北神农架大九湖为例

泥炭作为一种地质档案，其发育形成过程中包含了丰富的古气候和古环境的变化信息。由于泥炭沉积中植物残体的碳、氧等稳定同位素组成与气候变化之间存在着密切关系，其稳定同位素时间序列已作为气候变化的代用指标逐渐用于古气候的恢复和重建，尤其是在以高时间分辨率重建全新世以来的气候环境变化方面已取得一些重要进展。 本论文通过对湖北省神农架地区大九湖泥炭中植物残体的氧、碳同位素的研究，同时以温度和湿度这两种重要的气候参数代用指标，恢复和重建全新世以来中国中部地区的气候状况。通过本论文的工作并与其它相关成果综合对比研究，对从末次冰消期晚期和全新世以来中国中部地区气候状况有如下的认识： 1. 末次冰消期晚期至全新世阶段，大九湖泥炭纤维素δ18O敏感地记录了发生在约14.67～12.89 cal. kaBP的BA暖期以及在此期间所发生的两次冷事件：Oder Dryas冷事件和Intra-Allerød冷事件；并指示随后的Allerød暖期明显较Bølling暖期偏冷；在新仙女木时期（YD），神农架地区温度较低，事件中后期温度开始回升；在11.0～9.0 cal. kaBP的早全新世时期，大九湖泥炭δ18O在波动中升高，指示了整体上的温暖气候，期间存在一系列的气候变冷事件。这些冷事件基本都是叠加在一种长期的、相对较暖的变化趋势上，有别于末次冰消期的突然变冷事件；在9.0～5.0 cal. kaBP的中全新世阶段，神农架地区总体上处于相对温暖的适宜阶段，但波动较为频繁，期间记录到了著名的“8.2ka”冷事件；约5.0 cal. kaBP开始，大九湖泥炭δ18O值持续升高，指示以一次快速的升温过程开始了晚全新世阶段并保持在一个相对较高的温度水平；在整体温暖的气候背景下也明显记录有“4.2ka”、“小冰期”等全球性冷事件；大九湖泥炭纤维素δ18O所记录的温度变化趋势与中国大陆地区其他一些气候代用指标所记录的温度变化趋势有很好的相似性，说明中国大陆地区温度变化的趋势基本一致。 2. 大九湖泥炭δ18O温度变化序列所记录到的历次突然气候变冷事件，与格陵兰冰芯和北大西洋冷事件的发生具有很好的一致性，这说明对应于北半球高纬度区域的气候变化，在中低纬度的中国地区同样存在响应和变化，并且这种响应贯穿于整个全新世阶段。 3. 大九湖泥炭纤维素δ13C敏感地记录了末次冰消期以来东亚季风的演变历史。东亚季风在整个末次冰消期至晚全新世阶段始终处于一种强弱交替的波动态势。在末次冰消期至全新世早期，其整体上表现为一种由弱转强的态势；在全新世早期和中期阶段，东亚季风活动强度整体较高，表现为整个时间序列中的高活动时段，而其中也出现了数次明显的减弱迹象；全新世晚期阶段，东亚季风的活动强度较中期和早期为弱，整体上表现出低幅的波动但没有恢复到前两个时期的活动强度。在中世纪温暖期阶段的中后期，东亚季风的活动强度开始在波动中逐渐升高。 4. 该泥炭纤维素代用指标所记录的一些东亚季风突变（增强）事件与同一时期所发生的印度季风的突变（减弱）事件具有很好的对应关系；进一步证实这两个季风系统之间所存在的反相变化关系；同时，这些突变事件与北大西洋IRD冷事件在发生时间段也具有较好的对应关系，即每当北大西洋地区气候变冷时，东亚季风都表现出增强的迹象。 5. 综合分析中国泥炭同位素古气候记录和其它研究结果，对气候驱动机制有如下认识：当太阳活动发生百年至千年时间尺度的减弱时，由大气臭氧层变化所触发的影响向大气层下部延伸，导致北半球气候变冷；同时，减弱的太阳活动可能在赤道太平洋触发类厄尔尼诺状态出现，并引发印度洋夏季风减弱和东亚夏季风增强；早全新世北半球冰盖周围大冰湖冰岸坍塌，湖中巨量体积淡水突然流入北大西洋，导致海洋温盐环流传送带运转放慢甚致停顿，通过跨赤道的温盐环流向北输送的热量大大减少，引起北半球气候变冷；由于海洋温盐环流的变化改变了全球热量的分配，暖水在地球南部积累，导致西太平洋暖池区域海表面水与深层水温度之间反差的增加，从而有利于类厄尔尼诺状态出现，同样将可能引起印度洋夏季风减弱和东亚夏季风增强。

单种属泥炭纤维素碳稳定同位素组成与全新世青藏高原东部西南季风变化

泥炭的形成和积累主要受控于气候，其次是地质、地貌和水文等因素。作为一种重要和理想的气候信息载体，泥炭己经与冰芯、海洋及湖泊沉积、黄土堆积、洞穴碳酸盐沉积、树轮和珊瑚礁等其它类型的自然地质档案一样，逐渐为国内外致力于古气候变化研究的学者所接受，并将其重点应用于全新世以来气候变化信息的提取。本研究在已有的泥炭混合植物残体纤维素碳稳定同位素记录青藏高原东部地区气候信息的基础上，首次提取泥炭中单一种属植物残体一木里苔草（Calexmulieensis）纤维素，测定其碳稳定同位素，并以其时间序列作为一种新的西南季风代用指标，揭示该区域全新世以来气候变化。研究表明：1．木里苔草的碳稳定同位素时间序列是西南季风强度变化的敏感代用指标。约11800～11加0 cal aBP期间，木里苔草纤维素的613C记录处于最大值，表明该时段西南季风活动鼻弱，气候干冷，对应于普遍发生并存在的新仙女木事件；它清晰地指示了该区全新世的下限年龄为约11200 cal aBP（14c年龄约9900aB玲从约11200 oal aBP起该区迅速进入湿暖的全新世阶段，季风活动迅速增强；在约10800～5500 cal aBP期间，季风总体保持在强盛状态，但其间有4次突然减弱，气候变干冷；约从5500 cala即起季风活动在波动中逐渐减弱，其中有4次减弱最为明显。2．木里苔草纤维素碳同位素所记录的犯000年以来的所有9次西南季风活动的突然减弱与同时期北大西洋发生的冰力｝漂移碎屑沉积物事件（IRD事件）一一对应。这种密切的相关关系表明，西南季风强度的波动可能是对全球气候变化特别是对海洋热盐环流引起的地球南北方气撇动变化的响应。3．木里苔草纤维素碳稳定同位素所指示的西南季风有952，乓57，475，312，211和77年等一系列周期。其中557年和77年两个周期分别与北大西洋深层海水环流的550年的周期和76年的气候周期非常吻合。这表明西南季风与北大西洋气候间有很好的相关关系。由于557年和77年的季风周期又都分别类似于53。年和80年的太阳活动周期，这表明太阳活动可能对西南季风和北大西洋气候间的联系有着影响。4．红原泥炭木里苔草纤维素和泥炭混合纤维素别3c时间序列在千年至万年时间尺度上的变化趋势很相近。两种代用记录都一致反映了冰后期的气候变化，即均指示西南季风强度变化可分为三个明显的大阶段。这说明它们对过去12000年的西南季风变化具有相同的响应。对于目前经过较详细研究的那些全球大范围发生的突然气候变化事件，木里苔草纤维素δ~(13)C代用记录与泥炭混合纤维素δ~(13)C代用记录一样，都有相同的响应，但是，相对于泥炭中单一的木里苔草敏感地记录到历次北大西洋I劝事件而言，泥炭混合纤维素δ~(13)C记录对其中的几次突然气候变化事件似乎没有表现出明显的响应。这个结果表明对数百年尺度的突然气候变化，木里苔草纤维素比混合纤维素的酬3c指标似乎要更敏感一点。因此，在能获得足够数量的单种植物·残体的情况下，单种植物残体纤维素的δ~(13)C指标有很好的使用价值。

Removal of endotoxin from human serum albumin solutions by hydrophobic and cationic charged membrane

A novel matrix of macropore cellulose membrane was prepared by chemical graft, and immobilized the cationic charged groups as affinity ligands. The prepared membrane Fan be used for the removal of endotoxin from human serum albumin (HSA) solutions. With a cartridge of 20 sheets affinity membrane of 47 mm diameter, the endotoxin level in HSA solution can be reduced ro 0.027 eu/mL. Recovery of HSA was over 95%.