Syntheses of indenyl lanthanide derivatives and the molecular structures of [(C9H7)(2)PrCl(THF)](2) and [(C9H7)(3)La(THF)]

The reaction of anhydrous PrCl3 with Na(C9H7) in 1.2 mole ratio in THF gives [(C9H7)(2)PrCl(THF)](2)1. 1 crystallized in monoclinic system, space group P2(1)/c with a = 7.808(2), b = 17.796(6), c = 14.070(4) Angstrom, beta = 93.97(2)degrees, V= 1950.3(9) Angstrom(3), Dcalcd = 1.63 g/cm(3) and Z = 2. Each Pr ion is surrounded by two indenyl, two Cl and one THF in a roughly trigonal bipyramid arrangement with average Pr-C(ring) and Pr-Cl distances of 2.81 and 2.84 Angstrom. The reaction of LaCl3 with Na(C9H7) in 1:3 mole ratio gives (C9H7)(3)LaTHF 2, which crystallizes in the monoclinic space group P2(1)/a with unit cell constants a = 21.871(8), b = 10.585(3), c = 23.652(7) Angstrom,beta = 114.62(2)degrees, V = 4977.9 Angstrom(3) and Z = 8. (C) 1997 Elsevier Science S.A.

Laser light-scattering study of novel thermoplastics .1. Phenolphthalein poly(aryl ether ketone)

Five different molecular weight phenolphthalein poly(aryl ether ketone) (PEK-C) fractions in CHCl3 were studied by static and dynamic laser light scattering(LLS). The dynamic LLS revealed that the PEK-C samples contain some large polymer clusters. These large clusters can be removed by filtering the solution with a 0.1-mu m filter. We found that the persistence length of PEK-C in CHCl3 at 25 degrees C is similar to 2 nm and the Flory characteristic ratio, C-infinity is similar to 25. Our results showed that [R(g)(2)](1/2)(z) = (3.50+/-0.20) x 10(-2)M(w)(0.54+/-0.01) and [D] = (2.37+/-0.05) x 10(-4)M(w)(-0.55+/-0.01), with [R(g)(2)](1/2)(z), M(w), and [D] being the z-average radius of gyration, the weight-average molecular weight, and the z-average translational diffusion coefficient, respectively. A combination of static and dynamic LLS results enabled us to determine D = (2.20+/-0.10) x 10(-4)M(-0.555+/-0.015), where D and M correspond to monodisperse species. Using this calibration between D and M,we have determined molecular weight distributions of five PEK-C fractions from their corresponding translational diffusion coefficient distribution.

A DYNAMIC LASER LIGHT-SCATTERING STUDY OF CHITOSAN IN AQUEOUS-SOLUTION

The solution behavior of four chitosans (91% deacetylated chitin) with different molecular weights in 0.2M CH3COOH/0.1M CH3COONa aqueous solution was investigated at 25 degrees C by dynamic laser light scattering (LLS). The Laplace inversion of the precisely measured intensity-intensity time correlation function leads us to an estimate of the line-width distribution G(Gamma), which could be further reduced to a translational diffusion coefficient distribution G(D). By using a combination of static and dynamic LLS results, i.e. Mw and G(D), we were able to establish a calibration of D = k(D)M(-alpha D) with k(D) = (3.14 +/- 0.20) X 10(-4) and alpha(D) = 0.655 +/- 0.015. By using this calibration, we successfully converted G(D) into a molecular weight distribution f(w)(M). The larger alpha(D) value confirms that the chitosan chain is slightly extended in aqueous solution even in the presence of salts. This is mainly due to its backbone and polyelectrolytes nature. As a very sensitive technique, our dynamic LLS results also revealed that even in dilute solution chitosan still forms a small amount of larger sized aggregates that have ben overlooked in previous studies. The calibration obtained in this study will provide another way to characterize the molecular weight distribution of chitosan in aqueous solution at room temperature. (C) 1995 John Wiley & Sons, Inc.

THE EFFECT OF RADIATION-INDUCED CROSS-LINKING ON THE RELAXATION OF TAUT TIE MOLECULES DURING ANNEALING OF DRAWN LDPE

Shrinkage, retractive stress, and infrared dichroism of the drawn low-density polyethylene (LDPE) as-drawn and irradiated by Co-60-ray have been measured under different annealing conditions. The shrinkage and the disorientation of the irradiated sample was undergone more rapidly than that of unirradiated one as the temperature was continuously increased, surpassing a certain value, and a higher degree of shrinkage and disorientation was achieved finally for the irradiated sample when the samples were annealed with free ends. For the samples heated isothermally with fixed ends, the retractive stress went through a maximum and then attenuated to a limited value, and the degree of such a stress attenuation for the unirradiated sample was much more than that for the irradiated sample. These results show that the taut tie molecules (TTMs) in drawn PE can relax by the pulling of chain segments out of crystal blocks that they anchored in at elevated temperatures higher than the a transition and also by the displacing of microfibrils if the samples were annealed with free ends. The cross-links produced by irradiation prohibit the former process. It was further observed that the dependence of the average extinction coefficient of the band at 2016 cm-1 on that of the band at 1894 cm-1 is related to irradiation and annealing conditions, which has also been explained by the relaxation of TTMs and the function of irradiation-induced cross-linking on the relaxation.

SYNTHESIS AND CRYSTAL-STRUCTURE OF K4H2[PMO9V3O40].10H2O

The crystal structure of the title compound was determined from single crystal X-ray diffraction at -90-degrees-C. The complex crystallizes in the tetragonal P4/mnc, Z = 2, a = 12.515(3), c = 17.636(7) angstrom. The structure was solved by Patterson and Fourier techniques and refined by least-squares to R = 0.061 for 788 reflections. The central PO4 is disordered, P-O = 1.54 angstrom, M(M = Mo or V) is 6-coordinate, M-O = 1.62-2.48 angstrom, K is 7-coordinate, K-O = 2.84-3.10 angstrom.

K_4H_2[PMo_9V_3O_(40)]·10H_2O的合成及其晶体结构

采用低温技术,用 X 射线单晶衍射法测定了标题化合物的结构.晶体属 P4/mnc 空间群,a=12.515(3),c=17.636(7),Z=2.用788个独立可观测反射精修所有结构参数得 R=0.061.钼钒磷杂多酸阴离子中,PO_4四面体是无序的,P—O 键长1.54.M(Mo,V)是6配位,M—O 键长1.62—2.48.K 是7配位,K—O 键长2.84—3.10.

裂解色谱法分析苯乙烯-丙烯酰胺共聚物

本文报道了用裂解色谱法分析一种新型的苯乙烯-丙烯酰胺共聚物的研究结果。考察了裂解温度、共聚物组成同主要裂解产物之间的相关性。提出了用相关曲线对不同类型共聚物的组成进行定量测定和鉴别的方法。讨论了由于分子链结构的差别导致无规和嵌段共聚物的不同的裂解行为。

激光光热偏转光谱技术在薄层色谱定量分析上的应用

本工作研究了激光光热偏转光谱技术在高效薄层色谱检测中的应用。用这种技术定量检测品红和结晶紫的色谱圆班,获得的检测下限分别为0.3ng和0.4ng,与传统的漫反射分光光度检测法相比,使测定灵敏度提高1～2个数量级。

The complete mitochondrial genome sequence of the cutlassfish Trichiurus japonicus (Perciformes: Trichiuridae) : Genome characterization and phylogenetic considerations

Mitochondrial genome sequence and structure analysis has become a powerful tool for studying molecular evolution and phylogenetic relationships. To understand the systematic status of Trichiurus japonicus in suborder Scombroidei, we determined the complete mitochondrial genome (mitogenome) sequence using the long-polymerase chain reaction (long-PCR) and shotgun sequencing method. The entire mitogenome is 16,796 by in length and has three unusual features, including (1) the absence of tRNA(Pro) gene, (2) the possibly nonfunctional light-strand replication origin (O-L) showing a shorter loop in secondary structure and no conserved motif (5'-GCCGG-3'), (3) two sets of the tandem repeats at the 5' and 3' ends of the control region. The three features seem common for Trichiurus mitogenomes, as we have confirmed them in other three T. japonicus individuals and in T nanhaiensis. Phylogenetic analysis does not support the monophyly of Trichiuridae, which is against the morphological result. T. japonicus is most closely related to those species of family Scombridae; they in turn have a sister relationship with Perciformes members including suborders Acanthuroidei, Caproidei, Notothenioidei, Zoarcoidei, Trachinoidei, and some species of Labroidei, based on the current dataset of complete mitogenome. T japonicus together with T. brevis, T lepturus and Aphanopus carbo form a clade distinct from Lepidopus caudatus in terms of the complete Cyt b sequences. T. japonicus mitogenome, as the first discovered complete mitogenome of Trichiuridae, should provide important information on both genomics and phylogenetics of Trichiuridae. (C) 2009 Elsevier B.V. All rights reserved.

中国近海浮游细菌生物量与生产力的生态分布特点

本论文研究了胶洲湾、东海和渤海的蓝细菌（Synechococcus）、生物量、异养细菌生物量和生产力的生态学特点。并在汇泉湾、渤海和东海用分极增减法对海洋蓝细菌在微型食物环（the microbial loop）中的作用进行了初步研究。在以上海区调查研究的时间如下：胶州湾：1993年2月、5月、9月11月，1996年5月、1999年3月、5月和12月。汇泉湾：1996年4月至1998年4月。东海：1997年2-3月，1998年7月。渤海1998年9-10月，1999年4-5月。研究结果如下：胶州湾：蓝细菌生物量的变化范围是11.4-0.03 mgC/m~3，季节变化是夏季>秋季和春季>冬季。其水平分布是除夏季蓝细菌生物量是沿岸浅水区向湾外递减外，其它三季（春、秋和冬季）是由湾外向湾内至沿岸浅水区递减。蓝细菌生物量与海水温度周年变化正相关，与季节海水温度的关系是秋、冬季分布变化一致，春、夏季分布变化相反。海水温度是影响胶州湾蓝细菌生物量分布变化的主要原因。异养细菌生物量和生产力的变化范围分别是29.8-1.62 mgC/m~3; 129.12-1.92 mgC/m~3.d。季节变化都是夏季>秋季、春季>冬季。夏季的异养细菌生物量和生产力水平分布趋势与蓝细菌生物量的分布变化相同。海水温度对异养细菌生产力的影响较对异养细菌生物量的影响大。异养细菌生产力相比（BP:PP）的变化在0.58-0.02之间，季节分布变化是夏季>秋季、春季>冬季。夏季表层的BP:PP由沿岸浅水区向湾心、湾口和湾外递减。东海：蓝细菌生物量的变化范围是46.72-0.011 mgC/m~3，夏季高平均是23.59 mgC/m~3，冬季低平均是3.61 mgC/m~3。冬季蓝细菌生物量的水平分布明显受黑潮的影响，在表面和20米层是由东南向西北方向递减。其垂直分布是冬季表层和20米层>底层，夏季是20米层>表层>底层；在连续站冬111站和410站变化都是中层>底层>表层。异养细菌生物量和生产力的变化范围分别是17.2-4.4 mgC/m~3（1997.2）；376.8-7.2 mgC/m~3.d。异养细菌生产力夏季高平均是35.1 mgC/m~3.d。异养细菌生物量的水平分布是由沿岸向外海递增（1997.2），异养细菌生产力的水平分布是冬季异养细菌生产力在32度断面有由沿岸向外递减趋势，PN断面的变化与冬季相似。垂直分布，冬季和夏季的异养细菌生产力的垂直变化在2断面是底层大于表面，PN断面则是表层大于底层，32度断面大多断站是底层大于表层。在连续站冬季111站异养细菌生产力的变化是底层>中层>表层，409站的变化是中层>底层>表层，夏季111站和410站都是中>底层>表层。异养细菌生物量（1997.2）表层分布变化与海水温度分布变化相似，底层变化相反。异养细菌生产力与初级生产力相比（BP:PP），冬季在0.04-0.30之间，平均为0.17；夏季在0.20-0.43之间平均0.32。冬季在长江口附近BP：PP有一个高值区是0.30，夏季在111站附近有一个高值区是0.43。从连续站111站和409’站观测发现底层的BP：PP明显高于表层。渤海：蓝细菌生物量秋季（16.6-0.37 mgC/m~3）比春季（0.44-0.015 mgC/m~3）高。其秋季的水平分布与海水盐度水平分布相同，与海水温度水平分布相反。异养细菌生产力秋季（189-62.2 mgC/m~3.d）与春季（193.2-49.8 mgC/m~3.d）相当。但秋季捕层BP普遍小于底层，而春季是表层普遍大于底层。根据颗粒分级培养实验结果，海洋蓝图细菌在微型食物环中的作用如下：在汇泉湾的春季和秋季蓝细菌可能主要被小型浮游动物（microzooplankton 20-200 μm）捕食。在渤海的春季和秋季也是同样结果。但在东海夏季的111站和410站附近（东海大陆架中部）微型浮游动物（nanozooplankton 2-20 μm）对蓝细菌的捕食压力明显。

皱纹盘鲍生长和抗逆相关新基因的初步研究

在刘晓研究员已构建的皱纹盘鲍全长cDNA文库及克隆随机测序的结果基础上，分析发现了皱纹盘鲍胸腺肽β（Tβ）cDNA全长，该序列全长487bp，生物信息学分析显示其含有一个135bp的开放阅读框（ORF），编码一个含44个氨基酸的蛋白质分子，另外其5'和3'非翻译区长度分别是69bp和283bp，3'端非翻译区具有AATAAA mRNA加尾信号及PolyA寡聚腺苷酸尾巴。采用荧光定量PCR的方法研究皱纹盘鲍Tβ的组织特异性发现，Tβ在各组织中均有分布，但在外套膜中高表达，推测和其组织结构中富含参与免疫分泌的颗粒有关。利用荧光定量PCR检测感染鳗弧菌后皱纹盘鲍腹足肌中Tβ在不同时间点的转录表达发现，Tβ基因表现出具有显著差异的时间依赖性，12h后Tβ基因的表达量明显升高，且在处理后24h达到最高值，然后表达量开始回落，至处理后72h，Tβ表达量基本降至初始值。推测皱纹盘鲍在受到病原菌侵染后Tβ基因表达量上调可能是由于Tβ基因参与了皱纹盘鲍的免疫反应，它可能在皱纹盘鲍的抗逆机制中发挥着重要作用。 发现了一个在皱纹盘鲍大小个体中差异表达的长1555bp含有完整3’端的新基因片断，暂命名为TH。利用荧光定量PCR检测皱纹盘鲍RwRh、J1Rh、J1Jm、RwJm 4个家系大小个体中TH基因的差异表达，发现其在大个体中的表达量显著高于小个体，推测其可能与皱纹盘鲍生长速度有某种关联。荧光定量PCR对皱纹盘鲍TH基因时空差异表达的研究发现，其在发育过程中的表达呈现出一定的规律性，即在围口壳幼虫期前始终保持较低水平的表达，当围口壳形成后表达量急剧增加，至幼鲍时达到最高值，在成鲍中也维持较高水平的表达，提示该基因可能调控壳的发育。同时，皱纹盘鲍TH基因具有组织特异性表达，在外套膜中的表达量显著高于其他组织，推测和其组织结构中富含参与壳形成的颗粒有关。另外还比较了皱纹盘鲍RwRh、J1Rh、J1Jm、RwJm 4个家系中TH基因的差异表达，结果发现在这4个家系中的相对表达呈现出一定的规律，即J1Rh＞RwRh＞RwJm＞J1Jm，可能有助于解释家系之间生物学性状上的差异。

牙鲆性腺分化发育及类固醇激素T和E2对性腺分化的影响

本文采用组织学手段研究了牙鲆性腺在分化、发育和成熟过程中的变化。然后，通过放射性免疫方法（RIA）测定了牙鲆仔稚幼鱼全组织匀浆液中的性类固醇激素—睾酮（T）和雌二醇（E2）的含量，并结合牙鲆血清中T和E2含量的年周期测定，从内分泌学水平探讨了T和E2在其性腺分化、发育和成熟过程中水平的变化规律。同时，采用高温和雌性激素对性腺未分化的普通和雌核发育牙鲆仔稚鱼进行诱导处理，获得了较高比例的雄性鱼/假雄鱼或100%雌性鱼；并研究了这些外界环境因子对牙鲆性腺分化、性别比率及体内T和E2水平的影响，藉此探讨了牙鲆性别决定与性腺分化的细胞学和内分泌学机制。 对牙鲆仔稚幼鱼性腺的组织切片观察发现，培育水温18~20℃下，孵化后第45天、平均全长<22.0±2.8 mm的牙鲆，其性腺分化尚未开始，属于原始性腺；在孵化后70日龄、平均全长为38.0±1.7 mm左右，部分个体中观察到卵巢的雏形，其余个体的性腺在此阶段以及之后的一段时间内变化并不明显；到了第110天、平均全长达到86.5±5.9 mm时，雌性个体卵巢出现了卵原细胞向卵母细胞的转变，标志着卵巢分化的结束。在90日龄、平均全长为63.5±3.4 mm的雄性牙鲆中，精原细胞快速增殖，并观察到了输精管结构；进一步的细胞学分化则出现在100日龄、平均全长为76.0±8.6 mm的个体中，此时可以看到精小叶的形成；在平均全长为140.0±15.2 mm时，精巢中出现初级精母细胞，标志着性腺分化的基本完成。 对牙鲆仔稚幼鱼全组织匀浆和成鱼血清中的T和E2水平的比较发现，在全长为6 mm左右的仔鱼中T和E2含量均较高。随后，在性腺分化过程中T含量大大降低，E2的含量急剧增高，而性腺分化后期E2含量又降到较低的水平。在雄性牙鲆成鱼中， 从精巢第Ⅲ期开始，T含量随着精巢的发育而增加，到了精巢第Ⅴ期性腺发育成熟并排精后，又降低到较低的水平；E2含量在从精巢第Ⅲ期发育至精巢第Ⅴ期过程中略呈降低的趋势，但是总体上来说没有明显的差异。在雌性牙鲆成鱼中，卵巢从第Ⅱ期到第Ⅳ期的过程中，T水平逐渐升高，在第Ⅴ期时则明显降低；而E2含量在卵巢第Ⅱ期时保持较低的水平，随着卵巢的发育，E2含量逐渐增高，在卵巢第Ⅳ期时达到最高水平，在第Ⅴ期产卵后又有所降低。在雌雄个体中T和E2均呈现周期性的变化。5月份随着水温的升高，雄性个体T和E2含量显著上升；到了9月份又逐渐下降至最低值。雌性个体E2含量自3月份开始增高，在5月份急剧升高，并在6月份达到最高值；在7月份的时候，E2突然降低，而到了8月份又有所回升；9月份之后E2逐渐降低并在1月份左右降到最低；而T的含量分别在2月份和6月份出现两次高峰。 温度诱导牙鲆幼鱼性腺分化的结果表明，牙鲆中存在明显的TSD机制，即其性腺分化因饲育水温的不同而变化：在一定温度范围内，随着饲育温度的增加，牙鲆的雄性比例逐渐增高，常温对照组和21℃组中的雄性比例分别为51.62%、60.00%，而在24℃和28℃高温组中，雄性比例显著高于对照组，分别达到73.33%和87.27%。T和E2含量测定显示，在性腺分化时期，高温和对照组中T含量没有明显的变化，而温度处理组中的E2水平则低于对照组，特别是在28℃高温组，其E2水平显著低于对照组（P<0.05）。外源E2处理性腺未分化的牙鲆幼鱼的结果也表明，牙鲆的死亡率与雌性化比率均为雌性激素剂量依赖型的。随着外源E2剂量的增加，雌性比率增加，但同时死亡率也增高。此期间T和E2水平比较发现，在性腺分化时期，对照组中的T含量稍高于雌激素处理组；而对照组中的E2含量高于0.2 ppm和2 ppm两个低剂量组，却低于20 ppm和100 ppm两个高剂量组。 同时，还对人工诱导培育的雌核发育牙鲆和性反转牙鲆进行了性腺发育观察，在所观察的雌核发育牙鲆个体中，其雌性比例为83.33%，而高温28℃饲育群体中的雄性比例（即假雄鱼比例）为91.67%；在雌性个体中，也有一定比例的个体性腺发育不正常，有的性腺发育较小，有的则缺少部分性腺。进一步对雌核发育成体的血清中T和E2含量进行测量，发现在普通牙鲆个体中T含量显著低于雌核发育个体，而E2含量则高于雌核发育牙鲆；在雌核发育牙鲆中，性腺发育不正常的个体比性腺发育正常的个体中的T含量稍高，而E2含量则显著低于正常雌核发育牙鲆个体和普通牙鲆个体（P< 0.05）。

八株海洋微生物次级代谢产物的研究

本论文选取4株胶州湾海洋放线菌和4株条斑紫菜丝状体相关丝状真菌，进行了次级代谢产物的分离纯化与鉴定，共得到78个单体化合物，其中10个为新颖结构。对部分纯化合物进行了抑菌，抗肿瘤活性测试，并对菌株进行了菌种鉴定。具体结果如下： 从胶州湾放线菌M491，M097，M361和M353得到40个单体化合物，其中6个为新颖结构化合物。从M491分离到14个单体化合物，包括2个新结构倍半萜15-hydroxy-T-muurolol (1a)和11,15-dihydroxy-T-muurolol (1b)，2个首次报道的微生物来源的倍半萜T-muurolol (2b)和3α-hydroxy-T-muurolol (2c)，2个新颖结构大环内酯chalcomycin C (7)和chalcomycin D (8)。制备了3-oxo-T-muurolol (2a)单晶体，纠正了前人发表的错误结构。从M353分离得到10个化合物，包括2个新颖倍半萜5-hydroxy-epi-isozizaene (28)和5,14-dihydroxy-isozizaene (30)。自M097和M361分别分离得到12个，4个已知结构化合物。 从健康条斑紫菜丝状体分离得到了12株真菌。从优势附生菌N5分离得到了12个化合物，包括phenylacetic acid (42)，p-hydroxyphenylethyl alcohol (43)和L-β-phenyllactic acid (49)等广谱抗生素和紫菜生长调节剂。 对分离自白斑病条斑紫菜丝状体真菌N27，EF8，GA4进行了次级代谢产物研究，分离得到38个单体化合物。从GA4分离得到了16个化合物，4个为新结构化合物，包括1个酰脲类化合物hualyzin (62)和3个phenalenone族新化合物7-methyl isonorherqueinone (69)，7,8-dimethyl atrovenetin (70)和8-methyl-deoxyherqueinone (73)。从真菌N27和EF8分别分离得到12个和2个已知结构化合物。 采用MTT法，对37株人体肿瘤细胞株活性表明：chalcomycin C (7)和chalcomycin D (8)具有非常强的细胞毒活性，其平均IC50分别为0.027 μg/mL和0.007 μg/mL。7,8-Dimethyl atrovenetin (71)和8-methyl deoxyherqueinone (73)具有中等细胞毒活性，其平均IC50分别为5.1 μg/mL和0.7 μg/mL。 此外，本文首次报道了几个已知化合物的细胞毒活性，分别是chalcomycin （0.015 μg/mL），kalamycin (0.06 µg/mL)，(+)-homononactic acid（1.9 µg/mL），(+)-nonactic acid（2.3 µg/mL），griseoviridin（3.9 µg/mL），cyclo（L-Trp-L-Phe）（3.3 µg/mL），WIN 64821（5.8 µg/mL）和3,5-dihydroxy-2-methyl-4-pyrone（3.3 µg/mL）。 菌种鉴定结果表明：M353归属链霉菌，GA4，N27归属青霉属，EF8归属曲霉属，N5为枝孢霉属。

Antioxidant activity of differently regioselective chitosan sulfates in vitro

Differently regioselective chitosan sulfates were prepared according to Hanno Baumann's methods. Their antioxidant potencies were investigated employing various established in vitro systems, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH)/superoxide/hydroxyl radicals scavenging, reducing power, iron ion chelating and total antioxidant activity. All kinds of sulfated chitosans (HCTS, TSCTS, SCTS, TCTS) showed strong inhibitory activity toward superoxide radical by the PMS-NADH system compared to Vc. According to the above-mentioned order their IC50 were 0.012, 0.040, 0.015, 0.022mg/mL, respectively, however, scavenging activity of Vc on superoxide radical was 68.19% at 2.0mg/mL. Scavenging activity of superoxide radical was found to be in the order of HCTS > SCTS > TCTS > TSCTS > Vc. Furthermore, all kinds of sulfated chitosans exhibited strong concentration-dependent inhibition of deoxyribose oxidation. Except for HCTS, others had stronger scavenging activity on hydroxyl radical than Vc. Scavenging effect of TSCTS on 1, 1 -diphenyl-2-picrylhydrazy] radical was little lower than that of BHA, but better than that of others. All kinds of sulfated chitosans were efficient in the reducing power, especially TSCTS. TSCTS and TCTS showed considerable ferrous ion chelating potency. The data obtained in vitro models clearly establish the antioxidant potency of all kinds of sulfated chitosans. These in vitro results suggested the possibility that sulfated chitosans could be effectively employed as ingredient in health or functional food, to alleviate oxidative stress. However, comprehensive studies need to be conducted to ascertain the in vivo safety of sulfated chitosans in experimental animal models. (C) 2004 Elsevier Ltd. All rights reserved.

Different responses to selection in two stocks of the bay scallop, Argopecten irradians irradians Lamarck (1819)

Two different stocks (A and B) of the bay scallop Argopecten irradialls irradians (Lamarck, 1819) were used to test mass selection on growth. Stock A was a descending stock from the initial introduction from U.S.A. in 1982, which had been cultured in China for about 20 years. Stock B was the third generation from a recent introduction from U.S.A. in 1999. Truncation selection was conducted by selecting the largest 11% scallops in shell length from Stock A and the largest 12.7% scallops from Stock B as parents for the respective selected groups. Before the removal of parents for truncation selection, equal numbers of scallops were randomly chosen from Stock A and B to serve as parents for the control groups. Offspring from the four groups were reared under the same hatchery, nursery, and grow-out conditions. Values of response to selection and realized heritability at larvae, spat and grow-out stages for Stock B were all significantly (P < 0.001) higher than its counterpart for Stock A. For Stock A, no significant response to selection was observed (P > 0.05) at any stage, and the realized heritability for shell length was 0.015 +/- 0.024 for larvae, 0.040 +/- 0.027 for spat, and 0.080 +/- 0.009 for grow-out, respectively. For Stock B, however, significant (P < 0.05) response to selection was observed, and the realized heritability for shell length was 0.511 +/- 0.010 for larvae, 0.341 +/- 0.022 for spat, and 0.338 +/- 0.015 for grow-out. On average, responses to selection at the three stages for Stock B was 30 x, 7.1 x, and 3 x higher than its counterpart for Stock A, respectively. Accordingly, realized heritability at above stages for Stock B was 33 X, 7.5 x, and 3.2 X higher than its counterpart for Stock A, respectively. Differences in response to selection and realized heritability between the two stocks are presumably due to differences in genetic variability. As the 20th generation from the initial introduction consisted of only 26 scallops, Stock A is known to be highly inbred, while inbreeding in Stock B is negligible. (C) 2004 Elsevier B.V. All rights reserved.