The suppression of Ge-132 on the Maillard reaction of BSA by fluorescence spectrum

The fluorescences of BSA and glycosylated BSA were observed respectively. The lambda(cm) of BSA was 340 nm; while the lambda(cm) of glycosylated BSA was 436 nm. Because the fluorescence spectra of them were different greatly, we can observe the suppression of Ge-132 on the Maillard reaction of BSA without any interference of itself. It was showed that the fluorescence intensity of glycosylated BSA increased continuously with the cultured time, Ge-132 may suppress the Maillard reaction of BSA greatly, and the suppressing efficicency would be 32 %. The key site of the Maillard reaction of BSA is free amino groups of alanine residues on N-terminal amino group, besides the epsilon-amino groups of intrachain Lysine residues.

The synthesis and thermotropic liquid crystalline behavior of the novel poly(aryl ether ketone)s containing chloro-side group

The novel poly(aryl ether ketone)s containing chloro-side group were synthesized by nucleophilic substitution reactions of 4,4'-biphenol and chlorohydroquinone with either 4,4'-difluorobenzophenone(BP/CH/DF) or 1,4-bis(p-fluorobenzoyl)benzene (BP/CH/BF) and their thermotropic liquid crystalline properties were characterized by a variety of experimental techniques. The thermotropic liquid crystalline behavior was observed in the copolymers containing 50 and 70% biphenol. Melting transition (Tm) and isotropization transition (Ti) both appeared in the DSC thermograms. A banded texture was formed after shearing the sample in the liquid crystalline state. The novel poly(aryl ether ketone)s had relatively higher glass transition temperature (Tg) in the range of 168 similar to 200 degrees C and lower melting temperature (Tm) in the range of 290 similar to 340 degrees C. The thermal stability (Td) was in the range of 430 similar to 490 degrees C.

Permselectivity of 4-aminophenol, paracetanol and phenacetin on the self-assembled n-alkanethiol monolayer modified gold electrode

The gold electrodes coated by n-alkanethiol with various chain lengths were used to study the permeability of uric acid, ascorbic acid, 4-aminophenol, paracetanol and phenacetin by means of linear sweep voltammetry. The results show that the optimum chain length is n=10. The improvements in the selectivity and the stability of the amperometric detection of these compounds in a flow stream were obtained by n-alkanethiol self assembled monolayers modified electrodes based on their differences in the hydrophobicity and the permeability.

FORMATION OF [C60C5H5] ADDUCT CATIONS AND THEORETICAL-STUDY OF THE ISOMERS

We study here the reactions between C-60 and planar C5H5+ cations that lead to the formation of [C60C5H5](+) adduct cations in the chemical ionization source of the mass spectrometer. The structures, stabilities and charge locations of some possible isomers of [C60C5H5](+): sigma-adduct, pi-complex, [1,4]- and [1,2]-addition cations, are studied by AM1 semiempirical molecular orbital calculations. We find that the most stable is the sigma-addition cation. Another interesting and stable structure is the pi-complex cation which is bonded by the electrostatic interaction at the inter-ring distance of 1.589 Angstrom with the C-5v symmetry. The C5H5+ cyclopentadienium cation seems to be an ''inverted umbrella'' sitting on a five-membered ring of the C-60 cage.

STUDIES ON STATES OF CYTOCHROME-C MOLECULES IN AQUOUS SOLUTIONS USING SYNCHRONOUS FLUORESCENCE SPECTROSCOPY

The states of cytochrome C molecules in aquous solution were studied with synchronous fluorescence spectroscopy, It was found that the synchronous fluorescent spectra of cytochrome C were contributed by tyrosine and tryptophan residues separately at Delta lambda = 20 nm and Delta lambda = 80 nm, The peak position in synchronous fluorescent spectra of tyrosine residues in cytochrome C molecule does not change with its concentration, but that of tryptophan residue changes with its concentration, Only one peak at 340.0 nm was observed in the dilute solution of cytochrome C, With increasing the concentration of cytochrome C, a new peak at 304. 0 nm appeared. The peak at 340.0 nm disappeared and only one peak at 304.0 nm was observed at a higher concentration of cytochrome C, It may originate from the change of aggregation states of cytochrome C molecules and it was considered that the peak at 340.0 nm was attributed to the monomer and peak at 304.0 nm was due to the dimmer or oligomers. When urea was added into cytochrome C solution in which both monomer and dimmer or oligomers exist, cytochrome C molecules do not denature in the range of the specific concentrations of urea. The concentration of monomer of cytochrome C molecules increased and that of aggregation slates decreased by adding urea, Therefore, the synchronous fluorescence spectroscopy can be used to identify monomer and aggregation states of cytochrome C molecules.

MODIFICATION OF POLYTETRAFLUOROETHYLENE BY RADIATION .1. IMPROVEMENT IN HIGH-TEMPERATURE PROPERTIES AND RADIATION STABILITY

Polytetrafluoroethylene (PTFE) has never been reported to form a network structure when subjected to high energy radiation. Results obtained in this work indicates that when irradiation is performed under 330-340-degrees-C in vacuo PTFE can be crosslinked

聚合物载体-稀土金属络合物的研究——Ⅹ.聚[苯乙烯-甲基丙烯酸β(甲基亚硫酰基)乙酯]载体-三氯化钕络合物对丁二烯聚合的催化作用

合成了聚[苯乙烯-甲基丙烯酸β(甲基亚硫酰基)乙酯]载体-三氯化公络合物(PSM·NdCl_3),以红外光谱,X-射线光电子能谱等方法对其作了表征。实验结果表明,PSM·NdCl_3是配键型聚合物戴体-稀土金属络合物;Nd离子在络合物中分布均匀;PSM·NdCl_3和不同烷基铝组成的体系对丁二烯聚合的活性差别很大;在PSM·NdCl_3分子中引入某种Lewis酸可以改善其催化活性,并探讨了催化活性中心的生成机理。

AN INFRARED SPECTROSCOPIC STUDY OF THE STRUCTURAL PHASE-TRANSITION IN THE PEROVSKITE-TYPE LAYER COMPOUND [N-C16H33NH3]2COCL4

The solid-solid phase transitions in the perovskite-type layer compound [n- C16H33NH3]2CoCl4 have been studied by infrared spectroscopy. A new phase transition at 340 K was found by comparison with differential scanning calorimetry results. A temperature dependence study of the infrared spectra provides evidence of the occurrence of structural phase transitions related to the dynamics of the alkylammonium ions and hydrogen bonds. The main transition at 374 K corresponds to the conformational order-disorder change in the chain, which probably couples with reorientational motions of the NH3 polar heads. GTG or GTG' defects appear in the high temperature disordered phase.

Evolutionary analysis of phycobiliproteins: Implications for their structural and functional relationships

Phycobiliproteins, together with linker polypeptides and various chromophores, are basic building blocks of phycobilisomes, a supramolecular complex with a light-harvesting function in cyanobacteria and red algae. Previous studies suggest that the different types of phycobiliproteins and the linker polypeptides originated from the same ancestor. Here we retrieve the phycobilisome-related genes from the well-annotated and even unfinished cyanobacteria genomes and find that many sites with elevated d(N)/d(S) ratios in different phycobiliprotein lineages are located in the chromophore-binding domain and the helical hairpin domains (X and Y). Covariation analyses also reveal that these sites are significantly correlated, showing strong evidence of the functional-structural importance of interactions among these residues. The potential selective pressure driving the diversification of phycobiliproteins may be related to the phycobiliprotein-chromophore microenvironment formation and the subunits interaction. Sites and genes identified here would provide targets for further research on the structural-functional role of these residues and energy transfer through the chromophores.

塔玛亚历山大藻(Alexandrium tamarense)对鲈鱼(Lateolabrax japonicus) 的危害机制研究

本论文选择在我国分离得到的一株有毒赤潮甲藻-塔玛亚历山大藻（Alexandrium tamarense，ATHK株），研究了其对一种我国沿海常见和典型养殖鱼类鲈鱼（Lateolabrax japonicus）的危害机制。首先研究了塔玛亚历山大藻（ATHK）对鲈鱼鳃结构的影响及其溶血毒性； 然后采用腹腔注射的方法，研究了高剂量塔玛亚历山大藻毒素（ATHK毒素：约为1.6×105 细胞，相应PSP为0.886µg STX Equal，相当于每克湿重的鲈鱼PSP注射量为0.0118µg STX Equal）和低剂量塔玛亚历山大藻毒素（ATHK毒素： 约为0.16×105 细胞，相应PSP为0.0886µg STX Equal，相当于每克湿重的鲈鱼PSP注射量为0.00118µg STX Equal）在鲈鱼体内代谢过程中对鲈鱼肝脏、肾脏和鳃组织的超微结构、Na+K+-ATPase活性、肝脏功能和肾脏功能的影响、以及对抗氧化系统酶活性和异生物质代谢酶的影响，以期从不同方面了解塔玛亚历山大藻及其所产水溶性毒素（ATHK毒素）对鲈鱼的毒害效应及机制，为有毒赤潮的有效管理提供一定的科学依据。 塔玛亚历山大藻（ATHK）对鲈鱼鳃组织影响的实验结果表明，该藻使鲈鱼鳃组织出现水肿现象，细胞间隙变大；粘液细胞颗粒不规则，颜色加深，颗粒发生凝集，有板结状；氯细胞线粒体内部基质凝集。不产PSP的一种亚历山大藻（AT-6）也使鲈鱼鳃出现水肿，且使细胞出现一定的固缩现象。显微镜观察发现鲈鱼鳃丝间存在有这两种亚历山大藻细胞。由此推测塔玛亚历山大藻ATHK和AT-6的表面结构可能具有能导致鲈鱼鳃组织水肿的机械作用。对人血细胞溶血实验结果表明塔玛亚历山大藻（ATHK）具有较强的溶血毒性，大小与藻的生长阶段和细胞密度都有一定的关系：指数期的溶血毒性最大，随细胞数目的增多，活性逐渐加大；藻细胞、细胞碎片、细胞内容物都有一定的溶血毒性，其中细胞碎片的活性最大。通过11种（株）产PSP的亚历山大藻、不产PSP的亚历山大藻以及标准PSP的实验结果表明这种溶血毒性是由藻细胞的其它非PSP物质造成的，且这种溶血毒性在产PSP的亚历山大藻中具有一定的普遍性。 塔玛亚历山大藻（ATHK）对鲈鱼组织超微结构实验结果表明：ATHK毒素（约为1.6×105 细胞，相应PSP为0.886µg STX Equal，相当于每克湿重的鲈鱼PSP注射量为0.0118µg STX Equal）能导致鲈鱼组织细胞超微结构发生剧烈的变化，主要表现在：肝细胞细胞膜有肿胀现象，部分膜边缘溶解；细胞质糖原颗粒化；核糖体脱落，仅见滑面内质网；细胞质和线粒体内都出现空泡，且线粒体的嵴状结构也发生变化；核膜溶解比较严重，核质外溢，且异染色质边际化。前肾细胞超微结构的变化主要是淋巴细胞核质出现空泡，核膜有溶解迹象；Ⅰ型粒细胞颗粒膨大，伪足增多且变长；Ⅱ型颗粒细胞颗粒增多，内部出现空腔，细胞膜和核膜溶解，胞质、细胞器和核质外溢。鳃组织中氯细胞的核膜局部溶解，核仁弥散，线粒体膜溶解，微细小管膨大；粘液颗粒膜溶解，内部结构遭受破坏；扁平细胞核膜及线粒体膜几乎全部溶解。因此，我们的结果表明，ATHK毒素能作用于鲈鱼细胞的内膜和外膜系统，使膜发生溶解、脱落等变化；比较注射同样剂量大小ATHK毒素120h和240h时鲈鱼组织超微结构发现，细胞超微结构在一定程度上能够恢复。 ATHK毒素对Na+K+-ATPase活性、肝脏功能以及肾脏功能的影响结果表明，0.16×105―1.6×105细胞范围内的ATHK毒素可以显著影响肝脏和鳃组织中的Na+K+-ATPase，使这两种组织中的Na+K+-ATPase活性出现不同程度的下降； 而且还能够显著抑制肝脏中谷丙转氨酶的活性，最大抑制率为95%。但此范围内的ATHK毒素不能显著影响肾脏中的Na+K+-ATPase活性以及尿素氮含量。因此，ATHK毒素对Na+K+-ATPase活性的抑制则会导致细胞能量的缺失，使细胞进一步发生其它变化，而ATHK毒素对肝脏功能完整性的影响则可能会抑制对蛋白质的分解代谢。 ATHK毒素对鲈鱼肝脏、肾脏和鳃组织中的、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱肝肽过氧化物酶（GSH-Px）以及谷胱肝肽转硫酶（GST）活性变化影响的结果表明：高剂量（约为1.6×105 细胞，相应PSP为0.886µg STX Equal，相当于每克湿重的鲈鱼PSP注射量为0.0118µg STX Equal）ATHK毒素能显著诱导鲈鱼肝脏和鳃组织中SOD、GSH-Px以及GST酶活性，最大变化范围为正常状态下的3-4倍，对肝脏中CAT酶活性具有一定的抑制作用，对鳃中的CAT抑制效应则不显著；但此剂量的ATHK毒素仅对肾脏鳃中的GSH-Px活性有一定的诱导作用，对SOD、CAT以及GST的活性没有显著影响。低剂量（约为0.16×105 细胞，相应PSP为0.0886µg STX Equal，相当于每克湿重的鲈鱼PSP注射量为0.00118µg STX Equal）ATHK毒素也能诱导鲈鱼肝脏和鳃组织中SOD、GSH-Px以及GST酶活性，其在第一个24h内的诱导效果与临界致死毒素剂量相似； 且连续注射低剂量ATHK毒素则对肝脏和鳃中这三种酶活性具有累加的诱导作用，使这三种酶活性的变化范围为正常的5倍；低剂量ATHK毒素对肝脏中CAT酶活性也具有抑制作用，但对鳃中CAT酶活性的抑制作用并不显著。 同样，低剂量ATHK毒素除对肾脏中GSH-Px活性具有一定诱导效应外，对SOD、CAT以及GST都没有显著影响。 SOD、GSH-Px以及GST酶活性的显著升高表明ATHK毒素在鲈鱼体内代谢过程中能诱导鲈鱼产生活性氧自由基，且GST活性的升高则说明作为细胞色素P450依赖的异生物质代谢酶，GST在ATHK毒素代谢过程中可能可以加速ATHK毒素的代谢。推测鲈鱼可以通过这三种酶降低ATHK毒素以及次生毒物活性氧自由基对鲈鱼的危害。

卫星高度计资料在海洋潮汐研究中的应用

本文依据收集到的392个地面验潮站8个主要分潮（M2、S2、K1、O1、N2、K2、P1及Q1）的调和常数，对现有7个全球大洋潮汐模式的准确度进行了检验，结果显示各模式在深海区域均达到了比较高的准确度，相互之间差别也不大。经验模式GOT00和CSR4.0、同化模式NAO99、反演同化模式TPXO7.0、数值同化模式FES2002和FES2004的M2分潮均方根偏差在3 cm左右，其它分潮（S2、K1、O1、N2、K2、P1及Q1）大约在1～2 cm。本文还依据中国近海18个岛屿的调和常数对其中的5个大洋潮汐模式的准确度进行了检验，结果表明，M2分潮均方根偏差在6～14 cm，明显高于大洋部分的偏差，其中日本国家天文台的潮汐模式NAO99在中国近海的结果相对较准确。 我们利用1992年8月至2008年8月的TOPEX/POSEIDON和JASON-1(T/P-J)卫星高度计资料，对沿卫星轨道的302816个站点进行了14个分潮的潮汐调和分析，得到了全球大洋潮汐的8个主要分潮以及2个气象分潮Sa、Ssa的经验同潮图。主要结果有：（1）各分潮在卫星上升轨道与下降轨道的交叉点(约7000个)相关性分析表明：M2分潮的振幅和迟角的相关系数很高（分别为0.9965和0.9961）；S2，K1，O1和Sa分潮也有较好的相关性（相关系数为0.94～0.99）；（2）该结果与392地面个验潮站吻合较好，其中M2分潮的振幅、迟角和向量的均方根偏差分别为：1.73 cm，2.340和2.93 cm；S2，K1和O1分潮的振幅、迟角和向量的均方根偏差为1 cm左右，5.250～7.270和1.5～2.1 cm，该精度与最近几年国际上的主要大洋潮汐模式的准确度相近；（3）首次通过卫星资料获得了Sa、Ssa分潮的同潮图。周期为1年的Sa分潮与大洋105个地面站相比，振幅、迟角和向量的均方根偏差分别为1.50 cm、18.360和2.16 cm。在此基础上，进一步分析了构成Sa、Ssa气象分潮的两个主要因素（海水密度以及海面气压）在全球的分布。 在T/P-J等卫星资料无法覆盖到南大洋和北冰洋，本文利用Princeton Ocean Model（POM）进行了数值模拟，模拟结果与162个地面实测站（其中南大洋30个，北冰洋132个）的观测比较一致。基于卫星资料分析的结果和数值模拟结果合并得到了全球大洋的8个主要分潮同潮图。在此基础上通过全球潮汐能量耗散的计算得到潮能通量的分布，并得到全球M2、S2、K1和O1分潮的潮汐能量耗散率为2.431TW、0.401TW、0.336TW和0.176TW。 本文还利用卫星资料对南海潮汐进行了研究，在中国南海，获得了主要的半日潮、全日潮、四分日分潮和长周期分潮（M2，S2，N2，K2，K1，O1，P1，Q1，M4, MS4，Sa, Ssa）的经验同潮图。与南海沿岸94个地面验潮站的数据符合得比较好，M2，S2，K1及O1等4个主要分潮的平均振幅差为2～4 cm，均方根偏差分别是9～11 cm.其它4个主要分潮N2，K2，P1，Q1的平均振幅差为1～2 cm，均方根偏差为2～4 cm。此外，本文还利用卫星高度计资料潮汐分析结果沿卫星轨道进行高通滤波，分离得出中国近海的M2，S2，K1及O1分潮的内潮信息。

中国对虾育种方法研究与遗传连锁图谱的构建

本研究以中国对虾为材料，以杂交育种和选择育种为目标，进行了系统的中国对虾杂交育种试验、生长性状遗传参数试验及其分子遗传连锁图谱的构建工作。结果表明以不同地理群体杂交作为基础群体，然后采用系统的选择育种方法可以获得较好的选择效果。构建的遗传连锁图谱为中国对虾分子辅助育种提供一定的基础。这些试验结果为中国对虾合理系统的育种工作提供了理论基础和数据支持。其具体结果如下： 1. 试验对中国对虾黄渤海水域乳山湾群体（WYP）和朝鲜半岛南海群体（WKN）的2个群体及其杂交后代不同月龄生长情况和存活率进行了研究，测量体长（TL）、头胸甲长（CL）、头胸甲宽（CW）、第2、3腹节高（HST）、第2、3腹节宽（WST）、体重（BW）和存活率共7个性状，计算各项指标的杂种优势率，并对各性状进行了方差分析和多重比较。其3月龄生长情况和存活率研究结果表明，存活率在乳山湾群体（WYP♀）× 朝鲜半岛南海群体（WKN♂）杂交后代出现杂种劣势外，其他指标都表现出不同程度的杂种优势(4.37%～23.96% )。除了存活率外，杂交后代生长性状均显著高于亲本，乳山湾群体（WYP♀）×朝鲜半岛南海群体（WKN♂）杂交后代高于朝鲜半岛南海群体（WKN♀）× 乳山湾群体（WYP♂）杂交后代，黄渤海水域乳山湾群体高于朝鲜半岛南海群体后代。为确定测量性状与中国对虾体重的相关程度，建立了用体长(X1)，头胸甲宽(X2)，第2、3腹节宽(X3)，头胸甲长(X4)，第2、3腹节高(X5)估计体重的多元回归方程：Y = －2.056 + 0.03X1 + 0.076X2 + 0.078X3 + 0.033X4 + 0.043X5。 2. 中国对虾黄渤海水域乳山湾群体（WYP）和朝鲜半岛南海群体（WKN）2个群体及其杂交后代在4月龄时期的6个生长指标和存活率的杂种优势范围在0.514%到14.95%之间，WYP♀×WKN♂杂交后代在这7个指标中都高于WKN♀×WYP♂杂交后代。5月龄杂交后代也表现出一定程度的杂种优势，其范围在-9.000%～19.090%之间，但头胸甲长、第2、3腹节处高和存活率3个指标出现杂种劣势。不同杂交组合各个阶段生长发育情况和存活率在杂种优势表现出一定的规律。随着月龄的增加，WKN♀×WYP♂杂交后代杂种优势率有所增加，而WYP♀×WKN♂杂交后代的却有所降低。ANOVA分析结果表明，杂交后代在存活率方面与双亲差异不显著。4月龄的分析结果发现杂交后代在WST和BW这2个指标上存在显著差异。LSD多重比较结果显示，WYP♀×WKN♂杂交后代在BW指标上与亲本存在显著差异，在WST指标方面与其他3个组合的后代差异显著。5月龄的数据分析结果发现，杂交后代除体重存在显著差异外，其他各项指标差异均不显著。LSD多重比较结果发现，WKN♀×WYP♂杂交后代体重与其亲本WKN存在显著差异。 3. 对2个野生群体——朝鲜半岛南海岸群体（WKN）和黄渤海群体（WYP）和3个养殖群体——朝鲜半岛群体的养殖一代（FKN），黄海1号（HH1）和即抗98（JK98）进行杂交试验的研究，结果表明JK98 (♀)  WKN (♂)组合在存活率方面最高，其余的依次为WYP (♀) WKN (♂)，WKN (♀) WYP (♂)，FKN (♀)HH1 (♂) 和 WYP (♀) FKN (♂)。而在体重方面FKN(♀)  HH1(♂)组合最高，其余的依次为WKN (♀) WYP (♂)，WYP (♀) WKN (♂)，WYP (♀)FKN (♂) 和 JK98 (♀)WKN (♂)。在所有生长性状方面，JK98 (♀)  WKN (♂)在5个组合中是最低的。方差检测结果表明，TL、CL、HST、LL和BW这5个指标在不同组合间存在差异，而其他指标不存在差异。多重比较结果发现JK98 (♀)WKN (♂)组合的TL与其他组合间差异极显著，HST指标与WKN (♀) WYP (♂)，FKN(♀)  HH1(♂)和 WYP (♀)  WKN (♂)这3个组合差异显著，BW指标与WKN (♀) WYP (♂) 和 FKN(♀)  HH1(♂)差异显著。 4. 通过人工授精的方法建立了中国对虾21个半同胞家系，测量了中国对虾21个半同胞（46个全同胞）家系的TL、CL、CW、HST、WST、第1腹节长（FL）、第6腹节长（LL）。利用MTDFREML软件得到生长性状遗传力在0.15~0.35之间，属于中度遗传力范围。TL的遗传力为0.34±0.071，CL的为0.30±0.070，CW为0.35±0.077，WST为0.33±0.073，HST为0.33±0.073，FL的最低为0.15±0.044，LL的为0.24±0.059。各个性状间表现出高的正相关，其中CW和TL以及HST的遗传相关最大，FL和WST的遗传相关最小。 通过以上杂交育种和选择育种的研究，认为单纯的依靠杂交育种来改善中国对虾的育种工作可能具有一定的局限性。所以在实际的育种过程中，以中国对虾不同群体的杂交后代作为基础群体，并以此为基础进行系统的选择育种应该具有更大的潜力。 5. 本试验利用中国对虾F2群体和AFLP分子标记技术进行了遗传连锁图谱的构建。利用55对AFLP引物组合对F2家系的110个个体进行了研究，结果检测到532个符合作图策略的AFLP标记。利用卡方检验检测分离位点是否符合孟德尔分离定律。对于符合3：1比例的分离位点利用F2自交模型构建性别平均连锁图谱，对于符合1：1比例的分离位点利用拟测交理论分别构建中国对虾的雌性和雄性遗传连锁图谱。雌性、雄性和性别平均遗传图谱分别有28、35和44个连锁群，图谱实际长度分别为1090、1617和1772.1 cM。中国对虾遗传连锁图谱估计基因组长度为2420 cM，符合与人类基因组相比的对虾类基因组长度。中国对虾雄性遗传连锁图谱比雌性遗传连锁图谱长32.6%，这可能说明中国对虾不同性别存在不同的重组率。通过皮尔逊相关系数检测认为AFLP标记在中国对虾图谱上分布均匀。本文利用AFLP标记构建的中国对虾遗传连锁图谱为中国对虾基因组研究和遗传改良提供一定的基础，同时也应该开发微卫星等共显性标记，为遗传连锁图谱的整合提供条件。

Preparation and in vitro antioxidant activity of kappa-carrageenan oligosaccharides and their oversulfated, acetylated, and phosphorylated derivatives

In order to study the relationship between chemical structure and properties of modified carrageenans versus antioxidant activity in vitro, K-carrageenan oligosaccharides were prepared through mild hydrochloric acid hydrolysis of the polysaccharide, and these were used as starting materials for the partial synthesis of their oversulfated, acetylated, and phosphorylated derivatives. The structure and substitution pattern of the oligosaccharides and their derivatives were Studied using FTIR and C-13 NMR spectroscopy, and their in vitro antioxidant activities were investigated. Certain derivatives of the carrageenan oligosaccharides exhibited higher antioxidant activity than the polysaccharides and oligosaccharides in certain antioxidant systems. The oversulfated and acetylated derivatives, which scavenge superoxide radicals, the phosphorylated and low-DS acetylated derivatives, which scavenge hydroxyl radicals, and the phosphorylated derivatives, which scavenge DPPH radicals, all exhibited significant antioxidant activities it, the systems examined. The effect of the molecular weight of the carrageenan on antioxidant activities, however, is not obvious from these studies. (c) 2005 Elsevier Ltd. All rights reserved.

Effect of parental stock size on F-1 genetic structure in the bay scallop, Argopecten irradians (Lamarck, 1819)

Three F-1 families of the bay scallop, Argopecten irradians, were produced from one, two and 10 individuals. The genetic changes in these populations, which suffered recent and different levels of bottleneck, were analysed using amplified fragment length polymorphism (AFLP) techniques. In the parental stock, a total of 330 bands were detected using seven AFLP primer pairs, and 70% of the loci were polymorphic. All F-1 groups had a significantly lower proportion of polymorphic loci when compared with the initial stock, and loss of the rare loci and reduction in heterozygosity both occurred. The progeny of the larger population (i.e., N=10) exhibited a lesser amount of genetic differentiation compared with the progeny from N=2, which showed lesser differentiation than progeny from N=1. The effective population sizes (N-e) in N=1, 2 and 10 were estimated as 1.50, 1.61 and 2.49. Based on regression analysis, we recommend that at least 340 individuals be used in hatchery populations to maintain genetic variation.

Salt-assisted acid hydrolysis of chitosan to oligomers under microwave irradiation

The effect of inorganic salts such as sodium chloride on the hydrolysis of chitosan in a microwave field was investigated. While it is known that microwave heating is a convenient way to obtain a wide range of products of different molecular weights only by changing the reaction time and/or the radiation power, the addition of some inorganic salts was shown to effectively accelerate the degradation of chitosan under microwave irradiation. The molecular weight of the degraded chitosan obtained by microwave irradiation was considerably lower than that obtained by traditional heating. Moreover, the molecular weight of degraded chitosan obtained by microwave irradiation assisted under the conditions of added salt was considerably lower than that obtained by microwave irradiation without added salt. Furthermore, the effect of ionic strength of the added salts was not linked with the change of molecular weight. FTIR spectral analyses demonstrated that a significantly shorter time was required to obtain a satisfactory molecular weight by the microwave irradiation-assisted inorganic salt method than by microwave irradiation without inorganic salts and conventional technology. (C) 2005 Elsevier Ltd. All rights reserved.