Distribution of microcystins in various organs (heart, liver, intestine, gonad, brain, kidney and lung) of Wistar rat via intravenous injection

The distribution of microcystins (MCs) in various tissues of Wistar rats was studied under laboratory conditions. Rats were injected intravenously (i.v.) with extracted MCs at a dose of 80 mu g MC-LRequivalent/kg body weight. MCs concentrations in various tissues were detected at 1, 2. 4, 6, 12 and 24 h post-injection using liquid chromatography-mass spectrometry (LC-MS). The highest concentration of MCs was found in kidney (0.034-0.295 mu g/g dry weight), followed by lung (0.007-0.067 mu g/g dry weight), stomach (0.010-0.058 mu g/g dry weight) and liver (0.003-0.052 mu g/g dry weight). The maximum MCs content in the whole body of rat, 2.9% of the injected dose, was observed at 2 h post-injection. MCs concentration was higher in kidney than in liver during the experiment, and two peaks of MCs concentration (at 2 and 24 h, respectively) were observed in kidney, indicating that MCs can be excreted directly via kidney of rat. Though heart, intestine, spleen, brain, gonad and stomach contained less than 0.2% of injected MCs during the whole experiment stage, the presence of MCs in these tissues represents potential damage to them. (c) 2008 Elsevier Ltd. All Fights reserved.

The effect of cyanobacterial crude extract on the transcription of GST mu, GST kappa and GST rho in different organs of goldfish (Carassius auratus)

The glutathione S-transferases play important roles in the detoxification of microcystin. Core-sequences of three classes of GST (mu, kappa and rho) were cloned from goldfish (Carassius auratus L) i.p. injected with cyanobacterial crude extract at two doses (50 and 200 mu g MC-LReq kg(-1) BW). The relative changes of the mRNA abundance in liver, kidney and intestine were analyzed by real-time PCR. The transcription of GST mu was inhibited in intestine at both doses and the transcription of GST kappa was inhibited from 12 to 48 h in kidney at both doses. The decreased transcription of GST rho was detected in all three organs at the high dose. It is suggested that transcription inhibition of GST rho might be significant in MCs toxicity at higher toxin concentration in omnivorous freshwater fish. Alteration in transcription of GSTs stimulated by MCs implicates an increased health risk to fish. (C) 2008 Published by Elsevier B.V.

Bioaccumulation of the hepatotoxic microcystins in various organs of a freshwater snail from a subtropical Chinese lake, Taihu lake, with dense toxic microcystis blooms

In this paper, we describe the seasonal dynamics of three common microcystins (MCs MC-RR, MC-YR, and MC-LR) in the whole body, hepatopancreas, intestine, gonad, foot, remaining tissue, and offspring of a freshwater snail, Bellamya aeruginosa, from Gonghu Bay of Lake Taihu, China, where dense toxic Microcystis blooms occur in the warm seasons. Microcystins were determined by liquid chromatography electrospray ionization mass spectrum. Microcystin (MC-RR + MC-YR + MC-LR) content of the offspring and gonad showed high positive correlation, indicating that microcystins could transfer from adult females to their young with physiological connection. This study is the first to report the presence of microcystins in the offspring of the adult snail. The majority of the toxins were present in the intestine (53.6%) and hepatopancreas (29.9%), whereas other tissues contained only 16.5%. If intestines are excluded, up to 64.3% of the toxin burden was allocated in the hepatopancreas. The microcystin content in the intestine, hepatopancreas, and gonad were correlated with the biomass of Microcystis and intracellular and extracellular toxins. Of the analyzed foot samples, 18.2% were above the tolerable daily microcystin intake recommended by the World Health Organization (WHO) for human consumption. This result indicates that public health warnings regarding human ingestion of snails from Taihu Lake are warranted. In addition, further studies are needed to evaluate the occurrence by Microcystis in relation to spatial and temporal changes in water quality.

Seasonal dynamics of the hepatotoxic microcystins in various organs of four freshwater bivalves from the large eutrophic Lake Taihu of subtropical China and the risk to human consumption

So far, little is known on the distribution of hepatotoxic microcystin (MC) in various organs of bivalves, and there is no study on MC accumulation in bivalves from Chinese waters. Distribution pattern and seasonal dynamics of MC-LR, -YR and -RR in various organs (hepatopancreas, intestine, visceral mass, gill, foot, and rest) of four edible freshwater mussels (Anodonta woodiana, Hyriopsis cumingii, Cristaria plicata, and Lamprotula leai) were studied monthly during Oct. 2003-Sep. 2004 in Lake Taihu with toxic cyanobacterial blooms in the summer. Qualitative and quantitative determinations of MCs in the organs were done by LC-MS and HPLC. The major toxins were present in the hepatopancreas (45.5-55.4%), followed by visceral mass with substantial amount of gonad (27.6-35.5%), whereas gill and foot were the least (1.8-5.1%). The maximum MC contents in the hepatopancreas, intestine, visceral mass, gill, foot, and rest were 38.48, 20.65, 1.70, 0.64, 0.58, and 0.61 mu g/g DW, respectively. There were rather good positive correlation in MC contents between intestines and hepatopancreas of the four bivalves (r = 0.75-0.97, p < 0.05). There appeared to be positive correlations between the maximum MC content in the hepatopancreas and the delta(13)C (r = 0.919) or delta(15)N (r = 0.878) of the foot, indicating that the different MC content in the hepatopancreas might be due to different food ingestion. A glutathione (GSH) conjugate of MC-LR was also detected in the foot sample of C. plicata. Among the foot samples analyzed, 54% were above the provisional WHO tolerable daily intake (TDI) level, and the mean daily intakes from the four bivalves were 8-23.5 times the TDI value when the bivalves are eaten as a whole, suggesting the high risk of consuming bivalves in Lake Taihu. (C) 2005 Wiley Periodicals, Inc.

The role of sense organs in the feeding behaviour of Chinese perch

Experiments were conducted to identify the rules of the individual sense organs in the feeding behaviour of Chinese perch Siniperca chuatsi by determining the consumption of natural food after selective removal or blocking of eyes, lateral lines and olfactory organs, and also by observing the behavioural response to visual, mechanical and chemical stimulation by artificial prey. Chinese perch were able to feed properly on live prey fish when either eyes or lateral lines were intact or functional, but could scarcely feed without these two senses. Chinese perch recognized its prey by vision through the perception of motion and shape, and showed a greater dependence on vision in predation when both visual and mechanical cues were available. Chemical stimulation by natural food could not elicit any feeding response in Chinese perch, and gustation was only important to the fish for the last stage of food discrimination in the oropharyngeal cavity. The sensory basis of Chinese perch in feeding is well adapted to its nocturnal stalking hunting strategy. and also explains its peculiar food habit of accepting live prey fish only and refusing dead prey fish or artificial diets. (C) 1998 The Fisheries Society of the British Isles.

Materials selection in mechanical design for microsensors and microactuators

Microsensors and microactuators are vital organs of microelectromechanical systems (MEMS), forming the interfaces between controller and environment. They are usually used for devices ranging in size at sub-millimeter or micrometer level, transforming energy between two or more domains. Presently, most of the materials used in MEMS devices belong to the silicon material system, which is the basis of the integrated circuit industry. However, new techniques are being explored and developed, and the opportunities for MEMS materials selection are getting broader. The present paper tries to apply 'performance index' to select the material best suited to a given application, in the early stage of MEMS design. The selection is based on matching performance characteristics to the requirements. A series of performance indices are given to allow a wide range comparison of materials for several typical sensing and actuating structures, and a rapid identification of candidates for a given task. (C) 2002 Elsevier Science Ltd. All rights reserved.

辽西中生代银杏目和茨康目植物生殖器官研究

本文研究了采自辽宁西部下白垩统义县组和上三叠统羊草沟组的三种植物的生殖器官，它们分别属于银杏目 (Ginkgoales) 和茨康目 (Czekanowskiales)。辽宁银杏 (G. liaoningensis Liu, Crane, Li et Wang sp. nov.) 和纤细堆囊穗 (Sorosaccus gracilis Harris 1935 emend. Liu, Hueber, Li et Wang) 是银杏目植物的雄球花，通过将这两种雄球花与现存银杏 (Ginkgo biloba L.) 雄球花的对比研究，讨论了自晚三叠世至今银杏目雄性生殖器官可能的演化途径。蟹形薄果穗 (Leptostrobus cancer Harris 1951 emend. Liu, Li et Wang) 是茨康目植物的雌性生殖器官，我们根据辽西标本对该种的特征集要做了修订，并对薄果穗属 (Leptostrobus Heer 1876) 的种进行了讨论，将三个种归并到蟹形薄果穗薄。主要内容包括： 1. 银杏属植物雄球花——辽宁银杏 采自中国辽宁下白垩统义县组的辽宁银杏，为葇荑花序状，主轴基部有鳞片。小孢子叶螺旋排列在主轴上，小孢子叶上着生3—4个 (少数为2个) 卵形到椭圆形的小孢子囊。小孢子囊下垂，纵状开裂。成熟花粉粒单沟，长椭圆形;而未成熟的花粉粒处在四分体阶段。辽宁银杏的特征和现存银杏十分相似。主要差别在于辽宁银杏的小孢子叶着生3—4个 (少数为2个) 小孢子囊，而现存银杏的小孢子叶绝大多数着生2个小孢子囊。辽宁银杏在大小及小孢子囊数目上区别于其它的银杏属雄球花化石种，如：英国约克郡侏罗纪的胡顿银杏 (Ginkgo huttoni (Sternberg) Heer) 雄球花，加拿大阿尔贝塔晚白垩世一个未定名的银杏属雄球花。辽宁银杏 (化石) 和银杏 (现存) 的比较支持了根据银杏属胚珠器官而提出的缩减假说，因为自早白垩世至今，银杏属雄球花小孢子叶着生的小孢子囊的数目经历了从3—4个到2个的减少。 2. 银杏目植物雄球花——纤细堆囊穗 本文研究的纤细堆囊穗采自中国东北上三叠统羊草沟组。这种雄球花小孢子 叶末端的裂片在形态上差异很大，这是在以前对这种植物的研究中没有发现的重要特征。这些保存精美的化石对于纤细堆囊穗特征的阐明和修订以及种的复原很有帮助。将中国的标本与西伯利亚堆囊穗 (Sorosaccus sibiricus Prynada 1962)、小堆囊穗 (S. minor Harris 1935)、乌马尔堆囊穗 (S. umaltensis Krassilov 1972) 和被定为长叶拜拉 (Baiera longifolia (Pom.) Heer 1876) 的雄球花进行了比较，发现它们与纤细堆囊穗在特征上一致，故将它们处理为纤细堆囊穗的异名。同时，也讨论了堆囊穗属可能的演化意义。它可能是银杏属的远祖，经过小孢子囊数目的减少和小孢子叶长度的缩短而演化到现在的银杏，而辽西早白垩世的辽宁银杏可能代表了堆囊穗和现代银杏在演化上的一个中间阶段。 3. 茨康目雌性生殖器官——蟹形薄果穗 本文研究的蟹形薄果穗采自辽西上三叠统羊草沟组和下白垩统义县组。羊草沟组的材料是蟹形薄果穗属最早的纪录，从而该种的分布在时间上有了新的资料：从晚三叠世到早白垩世。据标本穗轴顶端的完整性，我们修订了蟹形薄果穗的特征集要和提供了它的复原图，并将三种薄果穗归并到蟹形薄果穗。我们也回顾了薄果穗属自1876年建立以来100多年的研究历史，并列出了该属所有材料，还讨论了该属各种的主要特征和建种依据。

显性雄性核不育小麦不育株与育性近等基因系可育株不同器官的蛋白质比较研究

近年来作物杂种优势利用的研究取得了很大的进展，杂交种的应用带来了巨大的经济效益。作物杂种的生产通常借助于雄性不育系。但是某些植物雄性不育形成的分子机理尚未搞清，不育基因的结构与功能以及不育基因在表达过程中一系列的基因与蛋白质的相互作用有待揭晓。 显性雄性核不育小麦（太谷核不育小麦）是我国特有的显性雄性核不育无花粉型材料，其不育性是由显性单基因Ms2控制的。本论文以显性雄性核不育小麦不育株和可育株近基因系为材料，应用单向电泳（SDS－PAGE）和双向电泳（IEF／SDS－PAGE）方法，分析了不育株和可育株不同器官（种子、旗叶、幼穗及花药）的蛋白质组成。通过研究发现两者之间在蛋质组成上存在一些异同点。在胚乳和旗叶中，未发现不育株和可育株两者之间的蛋白质组成存在明显的差异。在外于减数分裂时期的幼穗和花药中，不育株和可育株之间蛋白质组成上有明显差异。与可育株相比，不育株缺少分子量分别为15.8kD、17kD、17．8kD、38kD、81．2kD的5个碱性蛋白质。另外，还发现不育株增加了一个16．2kD的低分子量酸性蛋白质。在某些特定分子量的蛋白质中，虽然两者都存在该蛋白质，但是在含量上有着明显的不同，可育株含量比不育株高。这些蛋白质组成的变化成为不育株的重要特征。本文首次报告了显性雄性核不育小麦不育株与近等基因系可育株不同器官中蛋白质组成的区别。本研究结果在蛋白质水平上证实了花器官是雄性败育基因表达的主要器官，Ms的表达具有较强的时间性和空间性。 本论文还对双向电泳方法进行了一些探讨。

几种作物非叶器官结构和功能的研究

本论文以小麦、水稻等几种重要经济作物为材料，应用透射电镜、扫描电镜、激光共聚焦显微镜以及氧电极，低温荧光等生理技术手段，对作物非叶器官的结构和主要生理特性进行了较全面和系统的研究。其中，比较分析了非叶器官叶绿体超微结构的差异，测量了非叶器官的放氧和低温荧光等生理指标，尝试从结构与功能相结合的角度，探讨非叶器官在提高作物产量中所起的重要作用。 首先以不同品种的小麦为实验材料，对其主要非叶器官－茎秆，从解剖结构、木质素含量、以及抗倒伏的力学特性等方面做了详细的比较研究。结果表明：高产小麦品种茎秆的秆壁厚度、茎截面积、机械组织厚度及细胞层数、维管束与其韧皮部的截面积等，均明显优于一般小麦品种。在茎秆薄壁组织细胞、机械组织细胞（厚壁组织细胞）和维管束的木质素含量上，高产品种也显著高于对照品种。另外，通过分析证明，小麦植株抗倒伏的能力与其茎秆高度、直径和髓腔直径等均有密切关系。因此，在超高产小麦品种的选育上，重视外源基因的引进，改进茎秆的结构特性及提高其木质素含量，可能是一个重要的选育方向。 气孔是植物器官吸收CO2 和放出O2 的主要通道，对光合作用的强弱有着决定性的作用。因此，对非叶器官表面气孔的研究显得尤为重要。通过对几种作物非叶器官气孔频度、气孔大小和气孔指数的研究，结果发现，非叶器官的气孔频度均较对应功能叶低;而气孔大小和气孔指数则变化较大。另外，本文还着重讨论了非叶器官气孔频度对作物光合作用的影响，并提出了在非叶器官中可能存在与此相适应的未知的光合类型 叶绿体是作物进行光合作用的场所，通过对小麦、水稻非叶器官及功能叶叶绿体超微结构的比较研究，发现非叶器官单个光合细胞中叶绿体的数量较少，体积也较小。其中小麦芒和颖片有发育较好的叶绿体结构，其基粒数可达普通叶的水平，但比旗叶少;外稃和穗轴都有完整的基粒跺叠，只是跺叠的数量较少;而内稃基粒少，基粒内囊体跺叠不整齐。随着小麦芒的衰老过程，其中叶绿体的数量也随之减少，并且这种减少的趋势在旗叶中先发生。非叶器官中叶绿体超微结构的这种变化和差异，暗示着非叶器官可能在作物的不同发育时期，对籽粒有重要作用。 通过对非叶器官和功能叶光合特性的比较研究，发现不同种作物非叶器官具有与功能叶不同的光合特性。在436nm 激发光下，非叶器官的F686／F734 明显高于旗叶;若以放氧为标准，比较功能叶和非叶器官的光合活性，发现以叶绿素为单位，非叶器官的放氧速率与旗叶相当，或甚至高于旗叶;以单穗为单位，最高可相当于旗叶的28％。另外，比较不同发育时期芒和旗叶的放氧速率，发现芒在作物的衰老后期，仍保持较高的光合活性。

疏叶骆驼刺的生物生态学研究

盐生草甸是新疆平原草地生物生产力最高的植被类型。而豆科植物疏叶骆驼刺则是盐毕草甸植被的常见种类。此项工作对疏叶骆驼刺天然分布的范围及其生态环境条件，特别是土壤水盐状况和与该植物相联系的植物群落类型进行了调查分析。本文通过对K、Na、Ca、Mg4种金属盐性元素在土壤—疏叶骆驼刺系统中的迁移进行分析，探讨该种植物在盐化土壤环境中的生长状况与主要盐性金属元素的相互关系;通过对包括土壤植物体内元素含量、土壤水盐状况、植株生长状况等指标的综合分析，研究其生态适应关系和种群与土壤水盐状况的关系;通过对植物器官形态解剖学的研究，探讨该种植物与盐生土壤环境生态适应的生物结构基础和耐盐的生理途径;通过对土壤盐化过程影响因素和土壤盐化趋势的分析，结合疏叶骆驼刺的生态学特性，探讨该种植物在新疆盐化土壤的可能利用价值。结果如下： 1、疏叶骆驼刺为中生适弱盐化的潜水草甸植物。在有潜水发育的地带，其生存适应土壤盐化环境的范围较广。 2、在天然条件下，疏叶骆驼刺以根萌生新芽繁殖方式为主。在弱盐化和土壤水分较充足的地带，可以种子繁殖再生新株。 3、作为盐生草甸植被与荒漠植被间过渡类型中常出现的种类，疏叶骆驼刺的种群消长代表了一定的土壤盐化的演替阶段。 4、该种植物的器官组织显微结构显示出其与盐化土壤环境关系上特殊的适应机制。 5、在植物的生长发育过程中，金属盐性元素的迁移积累变化的性质表明，在一定条件下，该种植物对土壤盐性具有改善作用。 6、面对新疆盐化土地使用状况和土壤盐化退化的趋势，疏叶骆驼刺的生态利用潜势很大。

大豆（Glycine max (L)Merr.）叶片和非叶器官光合特性探讨

本论文由三部分组成，一、大豆高产品种黑农40与低产品种黑农37不同发育时期叶片光合功能的比较研究。二、大豆非叶器官豆荚的光合特性。三、不同大豆品种叶片和非叶器官光合特性的比较分析。 一、 黑农40和黑农37不同发育时期叶片的光合特性。 以不同产量水平的东北大豆黑农40和对照品种黑农37为试验材料，研究了从幼苗期到衰老期五个不同发育时期叶片光合作用特性的变化。尤其是比较系统地研究了C4途径的表达，并通过相关分析，发现C4途径酶的活性与大豆的光合效率及其产量密切相关。主要研究结果如下： 1．测定不同发育时期大豆叶片净光合速率、DCIP光还原活力和1,5-二磷酸核酮糖羧化酶(RuBPcase)活力，结果表明，黑农40和黑农37叶片净光合速率均在初荚期达到最高值，而且不同发育时期的黑农40叶片光合能力均强于黑农37。 2．随着大豆叶片的发育和衰老，其叶绿素、类胡萝卜素的含量及Chla/b比值有一个逐渐升高，而后降低的过程。在同一发育时期，高产高光效品种黑农40光合色素含量均高于黑农37，有助于黑农40捕获更多的光能供光合作用所利用。 3．叶绿体吸收光谱及四阶导数光谱表明在整个生育期内以初荚期叶片对光能的吸收能力最强;而每一个发育时期黑农40叶片对光能吸收的能力均比黑农37高。荧光动力学参数表明，高产大豆黑农40叶片PSII活性(Fv/Fo)，光化学猝灭系数(qP)及PSII总的光化学量子产量也均高于对照品种黑农37的相应值：而黑农40的非光化学猝灭系数(qN)低于黑农37。说明高产大豆叶片具有与产量潜力相关的较高光能吸收和原初转化能力。通过对叶片及其叶绿体低温(77K)荧光发射光谱特性的分析表明，黑农40叶绿体对两个光系统之间激发能的调节能力优于黑农37。总之，黑农40对光能的吸收、传递和转化能力高于黑农37，从而能为碳同化提供更多能量。 4．通过研究苗期、开花期、初荚期、鼓粒期和衰老期等发育阶段的黑农40和黑农37叶片中磷酸烯醇式丙酮酸羧化酶(PEPCase)、NADP-苹果酸脱氢酶(NADP-MDH)、NADP-苹果酸酶(NADP-ME)、丙酮酸磷酸双激酶(PPDK)等C4途径的关键酶的活性变化，结合同位素14CO2喂饲试验，证明两种大豆叶片均含有C4途径四种关键酶，其原初产物含有有限的有机酸，说明有C4循环存在;而从PEPCase/RuBPcase的比值看，C4途径的酶在黑农40叶片中表达较高。通过相关分析，我们发现Pn与PSII光化学活性，RuBPCase及C4酶活性密切相关。这些结果还暗示有可能通过检测C4途径酶的表达水平及比例，筛选出具有高产潜力的大豆种质。 二、大豆非叶器官豆荚的光合特性。 通过对大豆非叶器官豆荚光合特性的研究，结果表明大豆豆荚的光合能力在鼓粒期达到最高值。通过叶绿体吸收光谱、荧光动力学和低温荧光等测定技术，我们发现鼓粒期的豆荚对光能的吸收、传递和转化有更高的能力;在鼓粒期不同品种的豆荚色素的含量也较高，从而有利于捕获更多的光能，供光合作用利用。DCIP光还原活力的测定结果表明鼓粒期豆荚也具有较高光合能力。 通过对大豆的初荚期、鼓粒期和衰老期豆荚RuBPCase和四种C4途径酶活性的研究，不仅证明非叶器官中有高活性的C4途径酶和存在有限的C4途径，而且鼓粒期豆荚有较高的碳同化效率。 三、不同大豆叶片和非叶器官光合特性的比较分析。 对三种大豆叶片、豆荚、种皮和子叶的色素含量和Chla/b进行测定，利用光谱技术、荧光技术及RuBPCase活性的测定，分析了大豆不同器官的光合特性。试验结果证明，非叶器官具有与叶器官相似的光合性能。与叶片比较，表明在非叶器官中具有非常高的C4酶活性。有利于补偿叶片开始衰老光合作用衰退的不足，因此非叶器官的这些光合特性有助于增加大豆光合产物的积累。