Characterization of the main light-harvesting chlorophyll a/b-protein complex of green alga, Bryopsis corticulans

The main light-harvesting chlorophyll a/b -protein complex (LHC II) has been isolated directly from thylakoid membranes of shiphonous green alga, Bryopsis corticulans Setch. by using two consecutive runs of anion exchange and gel-filtration chromatography. Monomeric and trimeric subcomplexes of LHC 11 were obtained by using sucrose gradient ultracentrifugation. Pigment analysis by reversed-phase high performance liquid chromatography showed that chlorophyll a (Chl a), chlorophyll b (Chl b), neoxanthin, violaxanthin and siphonaxanthin were involved in LHC 11 from B. corticulans. The properties of electronic transition of monomeric LHC II showed similarities to those of trimeric LHC II. Circular dichroism spectroscopy showed that strong intramolecular interaction of excitonic dipoles between Chl a and between Chl b exist in one LHC II apoprotein, while the intermolecular interaction of these dipoles can be intensified in the trimeric structure. The monomer has high efficient energy transfer from Chl b and siphonaxanthin to Chl a similarly to that of the trimer. Our results suggest that in B. corticulans, LHC II monomer has high ordered pigment organization that play effective physiological function as the trimer, and thus it might be also a functional organization existing in thylakoid membrane of B. corticulans.

Isolation of the main light-harvesting chlorophyll a/b-protein complex from thylakoid membranes of marine alga, Bryopsis corticulans by a direct method

The main chlorophyll a/b light-harvesting complex (LHC 11) has been isolated directly from thylakoid membranes of marine green alga (Bryopsis corticulans Setch.) by two consecutive runs of anion exchange and gel-filtration chromatography. LHC 11 proteins in the membrane extracts treated with 3% n-Octyl-b-D-glucopyranoside (OG) obtained specific binding ability on Q Sepharose column, and thus were isolated from the thylakoid membranes in a highly selective fraction. The monomeric, trimeric and oligomeric subcomplexes of LHC 11 have been obtained by fractionation of the LHC 11 mixes with sucrose density gradient ultracentrifugation. The SDS-PAGE analysis of peptide composition and absorption spectrum showed that LHC 11 monomers, trimers and oligomers prepared through this work were intact and in high purity. Our report is the first to show that it is possible to purify LHC If directly from thylakoid membranes without extensively biochemical purification.

Characterization of the artificially covalent conjugate of B-phycoerythrin and R-phycocyanin and the phycobilisome from Porphyridium cruentum

B-phycoerythrin (BPE) and R-phycocyanin (RPC) were purified from Porphyridium cruentum by Sephadex G-200 chromatography, then the BPE was attached covalently to the RPC by reacting their amino groups to form the artificially covalent BPE-RPC conjugate in which the excitation energy can transfer from the BPE to the RPC with low efficiency. Meanwhile, the intact phycobilisome (PBS) consisting of BPE, RPC, APC and L-CM was isolated and purified from Porphyridium cruentum, and the purified PBS was found to keep intact if the solution contains sucrose. Comparison of spectroscopic properties between the purified PBS and the BPE-RPC conjugate suggests that the BPE-RPC conjugate is much more stable than the purified PBS. The construction of BPE-RPC conjugate with low efficiency of the excitation energy transfer may be useful for preparing phycobiliprotein probes. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

Expression of hepatitis B surface antigen gene (HBsAg) in Laminaria japonica (Laminariales, Phaeophyta)

A transformation model for Laminaria japonica was established from 1993 to 1998, on the basis of which the transgenic kelp with heterologous gene encoding hepatitis B surface antigen (HBsAg) was obtained by using the micro-particle bombardment transformation method. Results of quantitative ELISA showed that HBsAg in transgenic kelp was 0.529 mug/mg soluble proteins on average and the highest value was 2.497 mug/mg, implying that recombinant HBsAg had natural epitope. Further support for the integration of HBsAg gene into kelp genome was obtained by PCR-Southern and total DNA hybridization. Prospect of kelp bio-reactor producing high value materials such as edible HBV vaccine was discussed as well.

Isolation, properties and spatial site analysis of gamma subunits of B-phycoerythrin and R-phycoerythrin

Polysiphonia urceolata R-phycoerythrin and Porphyridium cruentum B-phycoerythrin were degraded with proteinaseK, and then the nearly native gamma subunits were isolated from the reaction mixture. The process of degradation of phycoerythrin with proteinaseK showed that the gamma subunit is located in the central cavity of (alpha beta)(6) hexamer of phycoerythrin. Comparative analysis of the spectra of the native phycoerythrin, the phycoerythrin at pH 12 and the isolated gamma subunit showed that the absorption peaks of phycoerythrobilins on alpha or beta subunit are at 535 nm (or 545 nm) and 565 nm, the fluorescence emission maximum at 580 nm; the absorption peak of phycoerythrobilins on the isolated gamma subunit is at 589 nm, the fluorescence emission peak at 620 nm which overlaps the absorption maximum of C-phycocyanin and perhaps contributes to the energy transfer with high efficiency between phycoerythrin and phycocyanin in phycobilisome; the absorption maximum of phycourobilin on the isolated gamma subunit is at 498 nm, which is the same as that in native phycoerythrin, and the fluorescence emission maximum at 575 nm.

Comparison between compsopogon coeruleus and porphyra yezoensis in their O-2 evolution rates and phycobilisome composition

In order to investigate the possible effects of the ecological environment on photosynthetic activity and the major light harvesting complex, the oxygen evolution rates and composition of phycobilisome from marine red alga Porphyra yezoensis Ueda and freshwater red alga Compsopogon coeruleus (Balbis) Montagne, which could grow and reproduce under salinity up to 35 ppt, were studied. The results showed that the oxygen evolution rate of P. yezoensis in seawater was significantly higher than that of C. coeruleus in freshwater, and P. yezoensis tolerated inorganic ions at a relatively higher concentration than C. coeruleus. Moreover, the phycoerythrin (PE) of P yezoensis was R-phycoerythrin containing alpha, beta, and gamma subunits comprised phycoerythrobilin and phycourobilin. In contrast, the PE from C. coeruleus consisted of alpha, beta, and gamma subunits comprised only phycoerythrobilin but not phycourobilin, suggesting that the PE from C. coeruleus was of a new type.

Molecular cloning and functional analysis of cathepsin B in nutrient metabolism during larval development in Meretrix meretrix

Seed rearing is an important part in large scale clam culture industry. Since the nutritional history affects early development in bivalve, the condition of larval nutrition plays a key role in successful seed rearing. So far, the molecular mechanism of nutrient uptake in bivalve larvae is unclear. As one of the important proteolytic enzymes, cathepsin B of several organisms has been reported to be involved in digestion. We intended to analyze whether cathepsin B is involved in larval nutrient metabolism in the economic bivalve, clam Meretrix meretrix. The full length of M. meretrix cathepsin B (MmeCB) cDNA was cloned, which is 1647 bp with an open reading frame of 1014 bp. The deduced amino acid sequence encoded a preproenzyme of 337 residues with Cys-114, His-282 and Asn-302 composing cathepsin B activity center. The temporal and spatial expressions of MmeCB mRNA were examined from trochophore to post larva stages by whole mount in situ hybridization. In trochophore stage, no detectable signal was found. In the later three stages, MmeCB mRNA was detected in the digestive gland, suggesting a possible role of MmeCB in digestion. Moreover, MmeCB mRNA was also observed in the epidermal cells in D-veligers. Cathepsin B specific inhibitor (CA074 methyl ester) was applied to block the activity of cathepsin B in unfed larvae. The average shell lengths of treated larvae were smaller than that in control groups. The results of mRNA epidermal distribution and inhibitor treatment in D-veligers indicated that MmeCB may be also associated with other pathway of nutrient metabolism in larval epidermis. The overall results in this paper revealed that MmeCB might play a role in larval nutrient metabolism. (C) 2008 Elsevier B.V. All rights reserved.

Scophthalmus maximus cystatin B enhances head kidney macrophage-mediated bacterial killing

Cystatins form a large family of cysteine protease inhibitors found in a wide arrange of organisms. Studies have indicated that mammalian cystatins play important roles under both physiological and pathological conditions. However, much less is known about fish cystatins. In this report, we described the identification and analysis of a cystatin B homologue, SmCytB, from turbot Scophthalmus maximus. The open reading frame of SmCytB is 300 bp, which encodes a 99-residue protein that shares high levels of sequence identities with the cystatin B of a number of fish species and contains the conserved cysteine protease inhibitor motif of cystatin B. Constitutive expression of SmCytB is high in muscle, brain, heart and liver, and low in spleen. blood, gill and kidney. Bacterial infection upregulates SmCytB expression in kidney, spleen, liver and brain but not in muscle or heart. Functional analysis showed that recombinant SmCytB purified from Escherichia colt exhibits apparent cysteine protease inhibitor activity. Transient overexpression of SmCytB in head kidney macrophages enhances macrophage bactericidal activity probably through a nitric oxide-independent mechanism. These results indicate that SmCytB is involved in the immune defense of turbot against bacterial infection. (C) 2010 Elsevier Ltd. All rights reserved.

Expression of beta-carotene hydroxylase gene (crtR-B) from the green alga Haematococcus pluvialis in chloroplasts of Chlamydomonas reinhardtii

A carotenoid gene (crtR-B) from the green alga Haematococcus pluvialis, encoding beta-carotene hydroxylase that was able to catalyze the conversion of beta-carotene to zeaxanthin and canthaxanthin to astaxanthin, was cloned into Chlamydomonas reinhardtii chloroplast expression vector p64D to yield plasmid p64DcrtR-B. The vector p64DcrtR-B was transferred to the chloroplast genome of C. reinhardtii using micro-particle bombardment. PCR and Southern blot analyses indicated that crtR-B was integrated into the chloroplast genome of the transformants. RTPCR assays showed that the H. pluvialis crt R-B gene was expressed in C. reinhardtii transformants. The transformants rapidly synthesized carotenoids in larger quantities than the wild-type upon being transferred from moderate to high-intensity white light. This research provides a foundation for further study to elucidate the possible mechanism of photo-protection by xanthophylls and other carotenoids in high light conditions or through exposure to UV radiation.

25ka B.P.以来黑潮流域古环境演化对高频全球变化事件的响应

本文利用黑潮流域主流轴上的两个柱状沉积物岩芯MD05-2908以及PC-1为研究材料，在AMS14C测年的基础上，利用高分辨率的有机地球化学分析记录结合浮游有孔虫氧、碳同位素，恢复并重建了过去25,000 cal a BP以来黑潮流域古海洋环境演化的历史。以及表层海水生产力以及物质输送状况的演化历史。通过利用Uk’37古海水温度以及盐度指标恢复重建了过去25,000 cal a BP以来海洋表层海水温度、盐度；通过机碳、氮含量以及同位素变化、长链正构烷烃以及正构烷醇等指标重建了过去7000a B.P.以来的陆源物质输入历史；通过长链不饱和烯酮含量以及有机碳同位素指标恢复了过去7000a B.P.以来海水表层生产力的历史。此外，通过基于以上各种指标的环境信息与区域以及全球其它气候记录进行对比研究以及不同环境指标的时间系列分析，探讨了该区表层环流系统以及生产力的演化对于全球气候变化的响应，揭示了不同尺度的短周期高频率全球变化事件在黑潮流域的具体作用过程和响应机制。通过这些研究取得了以下的主要认识： 基于有机地球化学指标的古气候环境记录与黑潮流域已有的研究成果有很好的对应关系，从我们高分辨率的有机地球化学记录中可以识别出全新世黑潮强弱变化的几次明显的事件；25000a B.P.以来黑潮流域的环境变化与全球环境变化有着很好的对应性，黑潮强弱演化总体趋势与全球气候背景演化相一致，黑潮对高频气候变化事件的记录与全球记录具有同步性，这种同步性尤其体现在末次冰消期以来的气候快速高频振荡以及全新世以来的气候突变事件上。 全球性的高频气候事件对黑潮主体本身及黑潮流域的相邻区域的大气和海洋环流都具有重要的控制作用，这种控制作用主要通过副高、ITCZ以及季风三种气候要素之间相互关联、彼此影响造成的。具体表现为：太阳辐射量的减少导致热力差异减小，这种相对减小弱化了热带西太平洋的对流活动，造成了西太平洋副热带高压长期偏南、偏东，ITCZ平均北界位置偏南，降雨带长时间集中在南部地区，增强的降雨量提高了风化剥蚀以及沉积物向海洋搬运的能力，陆源物质供应量增加；同时，辐射量以及热力差的减小又与加强的东亚冬季风相联系，增强的冬季风导致了近底层“雾状层”物质的向海传输，物质传输效率增高。这种物源供应以及搬运量的双重增加导致了冲绳海槽流域物质通量的增加。 基于有机地球化学指标的海洋表层生产力的变化与陆源物质供应量以及黑潮流的强弱变化存在着对应关系，通常情况增加的海洋表层生产力对应着高的陆源物质输入以及相对较弱的黑潮。这种变化与东亚夏季风的以及冬季风的强弱都有很好的一致性。陆源物质的输入增加了表层营养物质的含量，导致生产力的勃发；陆源物质的输入增加又对应着减少的太阳辐射量，偏南的ITCZ北界位置以及副热带高压，这些对应于减弱的东亚夏季风（增强的东亚冬季风）。 黑潮流域的高沉积速率事件对应于减弱的黑潮强度和增加的ENSO频度，这些事件与上述的副热带高压、ITCZ位移和强弱的变化相一致。黑潮流域过去25000a B.P.以来南北温度的差异有冰期加大而全新世减小的趋势，但这种冰期与全新世的差异很小，我们认为末次盛冰期的时候黑潮主流轴没有移出冲绳黑潮，只是由于强度的减弱受陆架水体的影响有所加大。 黑潮流域很好的记录到了包括数千年尺度的D/O旋回周期到大气——海洋系统内部振荡所致的PDO、NAO等数十年尺度的高频振荡，说明黑潮流域对过去全球及区域环境变化事件有很好的响应。黑潮流域各古海洋指标所记录周期上的一致性说明这些环境因子控制机理上具有的一致性，即大背景上受太阳活动所引起的辐射量变化控制，局部的高频快速气候波动又受到局域性的气候因素如海气相互作用的放大影响。

中国明对虾核转录因子NF-κB家族基因的克隆与表达分析

对虾流行病爆发以来，我国乃至世界的对虾产业一直受到各种虾病的困扰，对虾养殖业严重受阻。解决这一问题的关键是加强对虾免疫机制的研究，并在此基础上寻找对虾疾病防治的有效方法。Rel/NF-κB是一类核转录因子，在无脊椎动物的先天性免疫中，起着极为重要的作用。 本论文根据其他无脊椎动物中NF-κB家族基因Relish和Dorsal的保守氨基酸序列分别设计简并引物，从中国明对虾血细胞cDNA中先后克隆到了Relish和Dorsal基因的部分片段，并结合SMART-RACE技术分别获得了中国明对虾Relish基因（FcRelish）和Dorsal基因（FcDorsal）的cDNA 全长。 FcRelish的cDNA 全长为2157个碱基，其中开放阅读框为1512个碱基，编码504个氨基酸；FcRelish蛋白的推导分子量为57373.5 Da，理论等电点为7.00。FcDorsal基因的cDNA 全长为1627个碱基，其中开放阅读框为1071个碱基，编码357个氨基酸；FcDorsal蛋白的推导分子量为39780.7 Da，理论等电点为8.85。 分析了FcRelish基因和FcDorsal基因的在血细胞、淋巴器官、肠和肌肉等12个组织中的表达水平。组织表达结果表明FcRelish和FcDorsal在淋巴器官和血细胞中表达水平明显高于其他组织，而淋巴器官和血细胞是对虾免疫系统中最重要的两个组织，由此可以推测中国明对虾中的Relish和Dorsal可能与免疫关系密切。 本论文还利用实时荧光定量PCR技术，对灭活鳗弧菌刺激，以及WSSV病毒刺激后，对虾血细胞和淋巴器官中FcRelish基因和FcDorsal基因的转录水平进行了研究。FcRelish基因在WSSV病毒刺激后，在血细胞和淋巴器官中都出现了波浪形变化，说明FcRelish对WSSV病毒刺激产生了应答。在灭活鳗弧菌刺激后，FcRelish在血细胞中变化不明显，而在淋巴器官中出现了两次明显的下调上调交替，出现这种现象的具体原因有待探究。在WSSV病毒刺激后，血细胞和淋巴器官中FcDorsal的转录表达呈波浪形变化。而在鳗弧菌刺激后，FcDorsal在血细胞和淋巴器官中的转录均在短时间内出现明显的上调表达，说明FcDorsal对鳗弧菌非常敏感。 作为核转录因子的NF-κB蛋白的转录激活作用需要在细胞质中通过蛋白水解作用来激活，为了进一步阐明NF-κB对病菌感染的应答机制，需要进一步研究这两种转录因子在蛋白水平的变化，以便从分子水平阐明NF-κB在对虾天然免疫中的作用。

菲律宾蛤仔（Ruditapes philippinarum)能量代谢的研究

能量代谢指动物在进行生理活动(如摄食、消化以及动物的活动等)时所消耗能量的总和，一般以动物的呼吸率利排泄率来估计动物的能量代谢。其主要研究内容是闸明生物能量代谢的基木规律以及与环境闪子的关系。菲律宾蛤仔(Ruditapesphil ippmarum)是我国一种重要的养殖贝类，关于其能量代谢的研究却较少，这种状况妨碍了菲律宾蛤仔养殖生态理论的完善和养殖技术的提高。本研究主要对菲律宾蛤仔呼吸率和排泄率的基本规律(能量代谢与体重的关系、能量代谢的昼夜变化)及其与环境因子(饵料浓度、水温、栖息底质环境)的关系进行探讨。研究结果如下：1．不同体重菲律宾蛤仔代谢率小同。实验川菲律宾蛤仔分三种大小：l(干肉重为0．07-0．14g)、ll(干肉重0．27-0．34g)、III(干肉重0．45～0．63g)。温度包括：26℃(八月)、20℃(十月)、1 5℃(十二月)、9℃(一月)。实验共设四个饵料浓度：2．28±0．25，6．454±0．44，10．284±0．82，15．414±1．56mgTPM／L(TPM，总颗粒物)，饵料中POM(颗粒有机物)含量都为4．68±1．64 mg/L。常温下菲律宾蛤仔代谢率随着体重的增大而增大。15℃、20~C、26℃时蛤仔呼吸率与干肉重呈明显的幂函数关系R=aW~b，a值变动范围为0．1076-0．3309；b值变动范围为0．239l～0．8381；蛤仔排泄率与干肉重也呈明显的幂函数关系N=aW~b，a值变动范围为14．213～68．362：b值变动范围为0．3673-1．1 532。9℃(饵料浓度为2．28±0．25mgTPM／L)、20℃(饵料浓度为10．284-0．82mgTPM／L)、26℃(饵料浓度为6．454±0．44mgTPM／L)时不同体重蛤仔氧氮比差异显著，其它情况下不同体重蛤仔氧氮比差异不显著。2．常温下菲律宾蛤仔代谢率受饵料浓度的影响，不同大小蛤仔受饵料浓度的影响程度不同。I组蛤仔呼吸率受饵料浓度的显著影响，II组III组蛤仔呼吸率只在9℃(一月)和26~C(八月)时受饵料浓度的显著影响。26℃时影响最显著，26℃时I组蛤仔在饵料浓度为2．28±0．25，6．45±0．44，l0．28±0．82，15．4l±1．56mgTPM／L时呼吸率分别是O．086，0．146，0．073，0．093(mlO_2／h)；ll组蛤仔在上述浓度饵料中呼吸率分别是0．138，0．214，0．J 26，0．12l(mlO_2／h);III组蛤仔在上述浓度饵料中呼吸率分别是0．129，0．266，0．186，0．192(mlO_2／h)。菲律宾蛤仔呼吸率在饵料浓度为6．45±0．44 mgTPM／L时最高，蛤仔呼吸率在其它饵料浓度时都会降低。菲律宾蛤仔排泄率在饵料浓度为10．28±0．82 mgTPM／L和15．4l士1．56mgTPM／L时显著高于其它浓度组，9℃时这种趋势更明显，9℃时饵料浓度为2．28±0．25，6．454±044，lO．284±0．82，15．41±1．56mgTPM／L中I组蛤仔排泄率分别是4．297，2．874，8．003，6．658(μgNH_3-N／h)；II组蛤仔在上述浓度饵料中排泄率分别是4．011，3．609，10．427，12．732(μgNH_3-N／h)；III组蛤仔在上述浓度饵料中排泄率分别是2．28 l，6．452，10．283，15．417(μgNH_3-N／h)。3．菲律宾蛤仔代谢率受自然温度的显著影Ⅱ向。I组蛤仔在9℃、15℃、20℃、26℃时呼吸率平均为0．057，0．085，0．039，O．099；II组蛤仔在上述四个温度中呼吸率平均为0．08，O．128，0．089，0．149(mlO_2／h)，I组和II组蛤仔在9℃和20~C时呼吸率较低，在26℃时呼吸率最高。III组蛤仔在上述四个温度中呼吸率平均为0．09，O．1 59，O．143，O．193(mlO_2／h)，在9℃时llI组蛤仔呼吸率显著低于其它温度组。温度为9℃、15℃、20℃、26℃时l组蛤仔排泄率平均为5．458，13．169，4．946，11．138(μgNH_3-N／h)：II组蛤仔在上述温度中排泄率平均为7．695，23．578，8．319，23．90l(μgNH_3-N／h)；III组蛤仔在上述温度中排泄率平均为11．738，27．443，15．658，35．407(μgNH_3-N／h)，蛤仔排泄率在15℃和26℃时均高于9℃和20℃。4．摄食状态与饥饿状态菲律宾蛤仔代谢率有明显不同。26℃时蛤仔静止状态呼吸率平均为0．336(m102／g干重．h)，摄食状态呼吸率平均为0．656(ml0_2干重．h)，摄食状态呼吸率比静止状态平均升高了0 32(ml0_2／g干重．h)；26℃时蛤仔静止状态排泄率平均为39．471(μgNH_3-N／g干重．h)，摄食状态排泄率平均为88．08(μgNH_3-N／g干重．h)，摄食状态排泄率比静止状态排泄率平均升高了48．6(μgNH_3-N／g干重．h)。摄食状态代谢率平均是静止状态的2～3倍。根据摄食引起的呼吸率和排泄率升高量得出每氧化产生lμgNH_3-N需0_2量平均为7．05μl。5．人工控制温度对菲律宾蛤仔代谢率有明显影响。不同大小蛤仔受温度的影响程度不同。在温度5℃、10℃、l 5℃、20℃、26℃，I组和II组蛤仔呼吸率都随着温度的升高而升高，在10℃～l5℃和20℃～26℃这二个温度变化范围内呼吸率变化最大，在20℃～26℃时I组蛤仔呼吸率变动范围为O．85～1．04(m10_2／g干重．h)、II组蛤仔变动范围为0．57～0．86(ml0_2／g干重．h)。III组蛤仔呼吸率只在5℃～l0℃时明显增高，变动范围为0．09～0．5l(m10_2／g干重．h)，在10℃～26℃范围内变化不大。I组和II组蛤仔排泄率随着温度的升高而升高，变动幅度较大，在5℃～26℃范围内其排泄率变动范围为10．32～81．53(μgNH_3-N／g干重．h)；而 III组蛤仔排泄率只在5℃～15℃时随着温度的升高而升高，其排泄率变动范围为6．75～23．77(μgNH_3-N/g干重．h)，在15℃～26℃范围内几乎不变。III组蛤仔的适温范围比I组和II组蛤仔广。菲律宾蛤仔在5℃和10℃时氧氮比变化明显，变动范围为2．76～11．44，在15～26℃时变化不大。6．菲律宾蛤仔代谢率有明显的日节律性，呈正弦曲线型变化。蛤仔夜问代谢率明显升高。I组蛤仔夜间呼吸率平均为0．867(m10_2／g干重．h)，白天呼吸率平均为O．504(m10_2／g干重．h)；II组蛤仔夜间呼吸率平均为0．438(m10_2／g干重．h)，白天呼吸率平均为0．36l(m102／g干重．h)；III组蛤仔夜间呼吸率平均为0．409(m10_2／g干重．h)，白天呼吸率平均为0．252(m102／g干重．h)。在22：00-23：00菲律宾蛤仔呼吸率最高。7．底质环境对菲律宾蛤仔的代谢率有明显影响。在饥饿状态下菲律宾蛤仔在泥沙底质中呼吸率平均为l 406(m10_2／g干重h)，在无泥沙环境中呼吸率平均为O．963(ml0_2／g干重．h)；摄食状态下菲律宾蛤仔在泥沙底质中呼吸率平均为1．59l(m102／g干重．h)，在无泥沙环境中呼吸率平均为1．115(m10_2／g干重．h)。在饥饿状态下菲律宾蛤仔在泥沙底质中排泄率平均为78．934(μgNH_3-N／g 干重．h)，在无泥沙环境巾排泄率平均为45．043(μgNH_3-N／g干重．h)；摄食状态下菲律宾蛤仔在泥沙底质中排泄率平均为87．12l(μgNH_3-N／g干重．h)，在无泥沙底质中排泄率平均为58．354(μgNH_3-N／g干重．h)。蛤仔在泥沙环境中呼吸率和排泄率都明显升高。

Proteasome and NF-kappa B inhibiting phaeophytins from the green alga Cladophora fascicularis

Chemical examination of the green alga Cladophora fascicularis resulted in the isolation and characterization of a new porphyrin derivative, porphyrinolactone (1), along with five known phaeophytins 2-6 and fourteen sterols and cycloartanes. The structure of 1 was determined on the basis of spectroscopic analyses and by comparison of its NMR data with those of known phaeophytins. Compounds 1-6 displayed moderate inhibition of tumor necrosis factor alpha (TNF-alpha) induced nuclear factor-kappa B (NF-kappa B) activation, while 2 and 4 displayed potential inhibitory activity toward proteasome chymotripsin-like activation. The primary structure-activity relationship was also discussed.

One step isolation and purification of liquiritigenin and isoliquiritigenin from Glycyrrhiza uralensis Risch using high-speed counter-current chromatography

High-speed counter-current chromatography (HSCCC) technique in semi-preparative scale has been successfully applied to the separation of bioactive flavonoid compounds, liquiritigenin and isoliquiritigenin in one step from the crude extract of Glycyrrhiza uralensis Risch. The HSCCC was performed using a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-acetonitrile-water (2:2:1:0.6:2, v/v). Yields of liquiritigenin (98.9% purity) and isoliquiritigenin (98.3% purity) obtained were 0.52% and 0.32%. Chemical structures of the purified liquiritigenin and isoliquiritigenin were identified by electrospray ionization-MS (ESI-MS) and NMR analysis. (c) 2005 Published by Elsevier B.V.

高寒草甸植物抗氧化系统对长期增强UV-B辐射的响应

通过研究自然条件下模拟平流层臭氧破坏5%时近地表面增加的太阳UV-B辐射对高寒草甸4种典型植物（矮嵩草Kobresia humilis、垂穗披碱草Elymus nutans、麻花艽Gentiana straminea和鹅绒委陵菜Po-tentilla anserina）的抗氧化系统的影响表明,尽管各植物的抗氧化系统组分变化不同,但4种植物的膜脂过氧化程度没有加剧,长期增强UV-B辐射没有对膜系统造成损伤。在自然长期增强UV-B条件下,4种植物的膜脂过氧化产物——丙二醛（MDA）含量与对照相比无显著差异。垂穗披碱草、鹅绒委陵菜的谷胱甘肽（GSH）含量增加,麻花艽的超氧化物歧化酶（SOD）活性与鹅绒委陵菜的过氧化氢酶（CAT）活性上升,同时麻花艽的类胡萝卜素（Car）含量亦显著增加。可见这些植物已能很好地适应UV-B强辐射,其抗氧化能力除了与抗氧化系统各组分的协同作用有关外,也可能与种的适应性有关。