Identification of a C-type lectin from the bay scallop Argopecten irradians

C-type lectins are Ca2+ dependent carbohydrate-recognition proteins that play crucial roles in the invertebrate innate immunity, such as nonself recognition, activation of proPO system, antibacterial activity, promotion of phagocytosis and nodule formation. In this study, a novel C-type lectin of bay scallops Argopecten irradians (Ai Lec) was identified using expressed sequence tag (EST) and RACE techniques. The Ai Lec cDNA encoded a polypeptide of 171 amino acids with a putative signal peptide of 21 amino acid residues and a mature protein of 150 amino acids. The deduced amino acid sequence of Ai Lec was highly similar to those of the C-type lectins from other animals and contained a typical carbohydrate-recognition domain (CRD) of 131 residues, which has four conserved disulfide-bonded cysteine residues that define the CRD and two additional cysteine residues at the amino terminus. The expression of Ai Lec transcript was dominantly detected in the hepatopancreas and slightly detected in the haemocytes of normal scallops. 6 h after Vibrio anguillarum-challenge and 8 h after Micrococcus luteus-challenge, the temporal expression of Ai Lec mRNA in hemocytes was increased by 4.4- and 3.6-folds, respectively. The results suggested that Ai Lec was a constitutive and inducible acute-phase protein and might be involved in immune response to Gram-negative and Gram-positive microbial infection in bay scallop A. irradians.

Purification and characterization of agarases from a marine bacterium Vibrio sp. F-6

Marine bacterium Vibrio sp. F-6, utilizing agarose as a carbon source to produce agarases, was isolated from seawater samples taken from Qingdao, China. Two agarases (AG-a and AG-b) were purified to a homogeneity from the cultural supernatant of Vibrio sp. F-6 through ammonium sulfate precipitation, Q-Sepharose FF chromatography, and Sephacryl S-100 gel filtration. Molecular weights of agarases were estimated to be 54.0 kDa (AG-a) and 34.5 kDa (AG-b) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH values for AG-a and AG-b were about 7.0 and 9.0, respectively. AG-a was stable in the pH range of 4.0-9.0 and AG-b was stable in the pH range of 4.0-10.0. The optimum temperatures of AG-a and AG-b were 40 and 55 degrees C, respectively. AG-a was stable at temperature below 50 degrees C. AG-b was stable at temperature below 60 degrees C. Zn2+, Mg2+ or Ca2+ increased AG-a activity, while Mn2+, Cu2+ or Ca2+ increased AG-b activity. However, Ag+, Hg2+, Fe3+, EDTA and SDS inhibited AG-a and AG-b activities. The main hydrolysates of agarose by AG-a were neoagarotetraose and neoagarohexaose. The main hydrolysates of agarose by AG-b were neoagarooctaose and neoagarohexaose. When the mixture of AG-a and AG-b were used, agarose was mainly degraded into neoagarobiose.

Identification of archaeon-producing hyperthermophilic alpha-amylase and characterization of the alpha-amylase

The extremely thermophilic anaerobic archaeon strain, HJ21, was isolated from a deep-sea hydrothermal vent, could produce hyperthermophilic alpha-amylase, and later was identified as Thermococcus from morphological, biochemical, and physiological characteristics and the 16S ribosomal RNA gene sequence. The extracellular thermostable alpha-amylase produced by strain HJ21 exhibited maximal activity at pH 5.0. The enzyme was stable in a broad pH range from pH 5.0 to 9.0. The optimal temperature of alpha-amylase was observed at 95 degrees C. The half-life of the enzyme was 5 h at 90 degrees C. Over 40% and 30% of the enzyme activity remained after incubation at 100 degrees C for 2 and 3 h, respectively. The enzyme did not require Ca2+ for thermostability. This alpha-amylase gene was cloned, and its nucleotide sequence displayed an open reading frame of 1,374 bp, which encodes a protein of 457 amino acids. Analysis of the deduced amino acid sequence revealed that four homologous regions common in amylases were conserved in the HJ21 alpha-amylase. The molecular weight of the mature enzyme was calculated to be 51.4 kDa, which correlated well with the size of the purified enzyme as shown by the sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

SmC2P1, a C2 domain protein from Scophthalmus maximus that binds bacterial pathogen-infected lymphocytes and reduces bacterial survival

C2 domains are protein structural modules found in many eukaryotic proteins involved in signal transduction, membrane trafficking, and immune defense. Most of the studied C2 domain-containing proteins are multi-domained in structure, in which the C2 domain is an independently folded motif and plays an essential role in calcium-dependent membrane-targeting. Although C2 domains isolated from intact proteins have been studied for biological functions, no study on natural proteins containing C2 domain only has been documented. In this study, we identified a Scophthalmus maximus protein SmC2P1 that is comprised of a single C2 domain and lacks any other apparent domain structures. The deduced amino acid sequence of SmC2P1 contains 129 residues and shares 36-38% identities with the C2 domains of the perforins of several fish species. Like typical C2 domains, SmC2P1 is predicted to organize into eight beta-strands with a Ca2+-binding site located in inter-strand loops. SmC2P1 expression was detected, in deceasing order, in liver, spleen, blood, brain, muscle, kidney, gill, and heart. Experimental challenge of turbot with a bacterial pathogen significantly upregulated SmC2P1 expression in kidney in a time-dependent manner. Recombinant SmC2P1 purified from yeast exhibits no hemolytic activity but binds to pathogen-infected kidney lymphocytes in the presence of calcium. Furthermore, interaction of recombinant SmC2P1 with bacterium-infected lymphocytes reduced bacterial survival. These results indicate that SmC2P1 is a functional protein that is involved in host immune defense against bacterial infection. (C) 2010 Elsevier Ltd. All rights reserved.

渤海沿岸第四纪地下卤水的水化学特征及其形成研究

中国北方的渤海沿岸地区是第四纪滨海相地下卤水最为典型的分布区。本文在收集前人有关该地区第四纪地下卤水的勘探和分析资料的基础上，通过与海水蒸发浓缩过程的对比研究，并运用多种数学统计分析方法、水文地球化学分析及化学热力学的地球化学模拟方法，全面分析了整个渤海沿岸地区第四纪地下卤水的水化学特征及其形成演化机制。研究结果表明：1.渤海沿岸的第四纪地下卤水具有与海水相近的元素化学组成，不同矿化度的卤水中各离子组分的含量变化关系与海水的蒸发浓缩过程相类似，地下卤水的形成与海水的蒸发浓缩过程有着密切的联系。 2.地下卤水中宏量离子组分的相对含量关系与单纯的蒸发浓缩海水之间存在着明显的差异，卤水中K~+、Na~+ 和SO_4~(2-)离子的含量普遍偏低，Mg~(2+)离子的含量总体偏高，反映出地下卤水水化学特征的形成并不仅是简单的海水蒸发浓缩的结果。3.研究结果还表明，在卤水的形成、演化过程中，石膏和碳酸盐的相转过程是影响卤水中Ca~(2+)、 HCO_3~-和SO_4~(2-)离子含量变化的主要地球化学过程，其中SO_4~(2-)离子的含量偏低还与地下还原环境中发生的脱硫酸反应过程有关。4.卤水中 K~+、 Na~+离子的含量偏低和Ma~(2+)离子含量的明显偏高是由卤水与围岩之间发生的阳离子交换吸附过程形成的；受钙的碳酸盐和硫酸盐转移过程及淡水的混合作用的影响， Ca~(2+)离子的含量变化在离子交换反应过程中表现得并不显著。5.对莱州湾南岸昌邑廒里地区地下卤水的地球化学模拟研究进一步表明，在渤海沿岸第四纪地下卤水的形成演化过程中，石膏和钙的碳酸盐的沉淀析出及阳高子交替吸附反应过程是影响卤水水化学特征形成的主要地球化学过程，很好地验证了前述水文行球化学推断。由于分析数据的欠缺，本文的研究对卤水中微量元素和同位素组分的地球化学过程未做讨论.

地下咸水的化学特征及其在水产养殖中的应用

地下咸水的化学成分与现代海水基本相同，它本身不带病毒，与海水也没有连接的渠道，故海水中的病毒宿主难以侵入，因此，它可以做为海水养殖的一种替代水体，在水产养殖方面有非常广阔的应用前景。本论文首次对用于养殖的胶州地区的地下咸水的形成原因和化学组分特征作了系统阐述。主要的研究内容和研究结果包括：1．咸水入侵和稀释作用是形成该地区地下咸水的主要原因。现代海水和卤水入侵及临近河口区淡水对地下卤水的稀释作用是形成该地区地下咸水的两种主要原因。地质调查结果表明，胶州地区属于地下卤水远景分布区，该地区有不边疆分布的斑块状的地下卤水存在，对地下水的超采造成地下水水位的下降，从而引起咸水入侵。在大沽河河口地区，河流淡水对地下卤水的稀释也是是该区地下咸水形成的一个原因。2．地下咸水的主要化学组分特征 在地下咸水的常量元素分布中，由于地下水流沉积物表面时产生的溶滤作用、离子交换吸附及还原环境下脱硫酸菌的作用使Ca~(2+)/Cl~-、Mg~(2+)/Cl~－、Na~+/Cl~-值与海水中的相应组分的比值相比，有不同程度的升高，SO_4~(2-)/Cl~-明显降低，K~+/Cl~-的值在不同的地区差异较大。通过对几个地区地下水中铁、锰的含量对比，发现其值远高于海水中的含量，可高达每升几毫克，这主要是由于在地下水的还原环境和较低的pH条件下，铁、锰的氧化物较易还原溶出，并讨论了不同地区的Mn/Fe值由于受Fe~(2+)、Mn~(2+)这两种还原产物稳定性的没和铁锰氧化物易被还原的程度不同这两个因素的影响，分别呈现出大于1和小于1的情形。对地下水中微量元素铜、铅、锌、镉的分析表明，这些元素在地下水中的含量与海水中的含量在同一个数量级，差异不显著。以Cl~-为参比因子，从所求得的相关关系来看，锌和铜在地下水中呈较好的保宋性分布，即没有显著的添加或去除行为，铅和镉的保守性较差。地下水中的营养盐分布与海水也有着显著不同，在地下咸水的Eh和pH分布范围内，NH_4~+态氮是地下水中无机氮分布的主要形式，并且由于吸附在粘土中的硅酸盐矿物的转出，地下咸水中的SiO_3~(2-)含量显著偏高。3．Ca~(2+)、Mg~(2+)对对虾生长的影响 利用正交实验证实了Ca~(2+)/Mg~(2+)比值、Ca~(2+)+Mg~(2+)总量以及二者之间的交互作用对对是生长都有显著性影响。对虾生长适宜的Ca~(2+)/Mg~(2+)比值范围是1:1～1:3，对是能在Ca~(2+)/Mg~(2+)比值为1：10的水环境中正常生长，只要有一定的Ca~(2+)+Mg~(2+)总量。较低的Ca~(2+)浓度可能会成为导致对虾存活率降低的原因。

海水中微量元素-碳酸钙共沉淀现象模拟：古海洋环境指标的实验研究

本文主要阐述运用稳定加液-反应系统，在实验室环境下模拟海水中方解石和文石形成时微量元素共沉淀现象，主要研究微量元素固-液体系中的迁移、转化和分配。进而在对其定量描述的前提下，研究各靶元素的共沉淀行为对各种反应条件的响应，从中提取出可以用于古海洋研究的替代性指标。所研究的微量元素和部分常量元素包括非金属元素硼和砷、碱土金属元素镁、过渡金属元素(锰、钴、镍、铜、和镉)、铀系元素(铀、钍和铅)以及钇和稀土元素。 本实验首先运用pH测试、高精度滴定分析等手段测定了实验的一些基本参数，如[H+]、碱度和[Ca2+]，根据计算获得了各碳酸体系要素，并以此为基础建立了5℃、15℃和25℃及pCO2=0.0015 atm.=0.0030atm.下的人工海水中方解石或文石的沉淀动力学方程。研究表明： 1)在各个条件下，方解石或文石的沉淀速率(R)和其在海水中过饱和度(Ω)存在很好的相关性，可基本表达为Log R=k*Log(Ω-1)+b； 2) pCO2对会严重改变海水中的碳酸钙过饱和度，进而影响相应的沉淀速率，但对方解石或文石的沉淀动力学方程没有明显影响； 3)不同温度下所得的方解石或文石各自的沉淀动力学方程存在明显差异，表明这一过程受热力学元素控制。 在方解石和文石沉淀实验中，通过人为添加各种微量元素对它们的共沉淀行为进行模拟。首先通过直接溶解稀释法结合ICP-MS或采用离线螯合系统前处理结合ICP-MS测定海水、固体样品中各靶元素的浓度。在此基础之上通过换算得出各靶元素在海水([Me]sol’n)和方解石或文石沉淀([XMe]overg)中的含量，然后 计算出单个实验中各靶元素介于碳酸钙沉淀和海水之间的分异系数。 实验中通过改变晶核类型(方解石和文石)、温度、pCO2、碳酸钙过饱和度(2-12，以方解石计)、沉淀速率和靶元素起始浓度等参数，得到在不同反应条件下各靶元素的分异系数。基于分异系数之间的差异，各靶元素在方解石和文石沉淀过程中的共沉淀行为被加以分类和界定。在方解石中Mn、Co、Ni、Pb、Th、Cd、Cu、Mg等表现为相容元素。而在文石中Mn、Co、Ni、Cd等都属不相容元素。B、As、U与其他金属离子不同的是这三种元素是以BO33-、AsO33-、UO22+等基团的形式参予共沉淀的，其中BO33-和AsO33-是替代CO32-而UO22+取代Ca2+。 进一步总结各靶元素和反应条件的关系，初步得出碳酸钙沉淀动力学机制、温度、离子半径、碳酸钙矿物的晶格结构、溶液化学组成及其变化是影响微量元素随方解石和文石共沉淀过程的重要因素，并对各靶元素共沉淀模式进行了探讨。最后我们结合实际工作主要是文献中报导的有孔虫、珊瑚等生物钙质壳体或骨架中各靶元素的结果，对比我们的实验从中提取出了一些可应用于古海洋研究的潜在替代性指标，如： 1) 海水中CO32-浓度代用指标——文石U/Ca、Cd/Ca比，方解石U/Ca比； 2) 海水pH 代用指标——文石B/Ca、As/Ca 比； 3) 氧化还原代用指标——方解石Mn/Ca 比； 4) 海水化学代用指标——方解石Co/Ca 比、U/Ca 比文石Cu/Ca、Pb/Ca 比。 5）稀土元素代用指标——方解石质载体中的YREE/Ca比。 还有几种元素组合也非常具有价值，如Mn-Co-Ni 组合、B-U 组合。此外指出了现有微量元素古海洋指标应用过程中被忽略了的一些关键性因素，如文石Mg/Ca比受到文石沉淀速率的限制、方解石Cd/Ca 比受到沉淀速率和温度的双重影响等。

中国对虾血淋巴凝集素的分离纯化及其性质研究

中国对虾是我国重要的海水养殖经济动物，但是其发展深受病害的影响，为进行病害防治及遗传育种等研究，对中国对虾免疫机理的研究成为迫切的需要。本论文重点研究了一种重要的对是体液免疫因子－凝集素的各种性质，包括成虾血淋巴中的凝集素对各种动物红细胞的凝集效价以及其随季节、体长等因素的变化。同时研究对比了不同虾种之间，针对同一种红细胞的凝集效价。通过筛选多种糖类、糖蛋白，最终找到中国对虾血淋巴凝集素的特异性抑制糖类－海带多糖（FGS）。海带多糖是一种有良好应用前景的药用多糖，具有一定免疫调节作用。用两种方法从中国对虾的血清中提纯了海带多糖特异性抑制凝集素，一种方法是利用该糖的性质，制备了亲和纤维素树脂柱；另一种方法是利用传统的离子交换柱，将血清进行两次连续过柱得到的。将两种方法得到凝集素进行了对比，发现性质非常接近，认为是一种物质，命名为中国对虾素(chinesin)。对中国对虾素的各种性质进行了研究，包括它的Ca~(2+)依赖性、分子量、对细菌的凝集作用、变性温度、氨基酸组成以及几种重要单糖的含量，并将这些性质与已经提纯的其他虾种的凝集素进行了对比。

褐藻胶的化学结构与吸附二价金属离子功能关系的研究

本文在测定由中国产海带（Laminaria japonica）、海蒿子（Sargassum pallidum）、海黍子（S.kjellmanianum)和鼠尾藻（s.thunbergii）提取的无损褐藻胶的糖醛酸组成和嵌段结构的基础上，较系统地研究了褐藻酸及其钠盐钙盐对二价金属离子的静态交换平衡特性与褐藻胶结构的关系，初步制成了具有离子交换性能的粒状褐藻酸钙树脂，开对干燥过的褐藻酸、褐藻酸钠和褐藻酸钙在水溶液中的吸附机理进行了探讨和比较。其结果如下：1. 海带、海蒿子、海黍子和鼠尾藻提取的褐藻胶具有不同的组成和嵌段结构，其M/G比值分别为1.86、1.50、1.22和1.27。文中引入结构参数η不胜数= (F_MG))/(F_M * F_G)，η值分别为0.62、0.13、0.36和0.41。后三种马尾藻褐藻胶与海带的结构和性质有差异，而海黍子和鼠尾藻胶在结构与性质方面比较接近。2. 褐藻胶的结构对吸附二坐金属离子具有很大影响，褐藻酸钠Cd-Sr交换反应的分离因子随着M/G比值的增大而增大；褐藻酸钙对Cu~(2+)离子的交换容量随着MG-嵌段比例（或η值）的增大而增大；褐藻酸对Sr~(2+)、Ba~(2+)、Cd~(2+)混合离子的总交换量随着M-嵌段比例的增大而增大。3. 干燥进的褐藻酸、褐藻酸钙以及褐藻酸钠在水溶液中具有不同的吸附机理。褐藻酸钠在溶液中，主要是二价离子诱导G-分子链协同聚合——“蛋箱模型”~(26)，褐藻酸吸附Cu~(2+)、Sr~(2+)时，除了离子交换外，还有使分子链聚合的螯合作作，分子链上未交换的 -COOH可能参与Sr~(2+)的配位，而Cu~(2+)无此现象。褐藻酸钙吸附Cu~(2+)时，可能有部分Cu~(2+)离子进入“蛋箱”内部替代Ca~(2+)离子而重新配位，但“蛋箱”的骨架不变，而吸附Sr~(2+)时，则表现出与离子交换剂截然不同的分子吸附行为。4. 不溶性的褐藻酸和褐藻酸钙具有较高的吸附选择性，尤其是粒状褐藻酸钙树脂的选择性高、稳定性好，可能应用于贵金属的回收、分离与废水处理等。

渤海海水主要化学成分的基本来源、发布和移除机制的研究

本文以渤海为研究体系，具体研究和探讨其海水主要化学万分（K~+、Na~+、Ca~(2+)、Mg~(2+)、Cl~-、So_4~(2-)、HCO_3~-）等来源、分布和移除等有关地球化学行为，并从理论分析和实际计算两方面来建立相应的模型并加以验证分析。鉴于渤的特殊地理环境（半封闭的内陆海）和地质，其海水主要成分可以认为基本上来源于周围陆地河流的输入。因此作者首先搜集并整理了各入渤海河流的多年水文和水化学监测数据，并提出了相应的统计和计算方法。结果给出了每年平均输入渤海的各有关成分量，其中黄河占据了主导地位，最为突出的是它的悬浮质占总量的91％。作者首次分析了渤海南、北部分海域的海水和表层沉积物的主要化学组成（项目基本同前）。结果显示，除紧靠河口的极小区域，渤海的海水组成相当一致，与大洋水的规律相同（仅绝对含量偏低）。进一步，作者根据相应的输入量（前文所述）计算了各有成分在渤海海水实际容量有限，而河流物质大量注入的结果。另一方面，渤海平均每3年多即与北黄海交换一次海水，说明各种成分在移除埋藏这前己经过多次充分的迁移的交换。根据离了缔合理论，作者计算了渤海海水主要化学成分的热力学平衡分布。计算中应用了最新的热力学数据，并对活度系数的计算作了改进。结果的最大特点表现在Cl~-的缔合物在各金属离子缔合物中居主要地位，考虑到海水中高浓度的Cl~-，本文的计算结果是可信的。从热力学稳定图解分析出发，作者认为在渤海具体条件下海泡石－坡缕石和伊利石具有自生反应的可能性。并且粘土矿物在渤海中Ca~(2+)置换Na~+的反应，黄铁矿、石膏和碳酸钙的生成反应均为可行。文中同时给出了相应的化学反应式。依据海洋这一特定的“稳态模式”－即动态平衡，作者对渤海海水主要化学成分的质量平衡进行了定量计算。其移除过程包括渤海与北黄海的海水交换作用；离了交换作用；间隙水埋藏与海水飞沫作用；伊利石的自生成反应；海泡石的自生反应；硫酸盐的生成反应和碳酸盐的生成反应。质量平衡计算结果令人满意。

中国对虾(Penaeus chinensis) 与鹰爪虾(Trachypenaeus curvirostris)生殖生物学及早期发育的比较研究

本文主要对中国对虾及鹰的生殖生物学及早期胚胎的发育进行了较为系统的比较研究。在前人工作的基础上对中国对虾及鹰爪虾的精子及精荚形成，精子的超微结构，纳精囊的形态及结构，卵子的激活，受精卵的卵裂等进行了比较研究。使用激光扫描共聚焦显微镜对中国对虾精管的结构及精子的形成过程进行研究。中国对虾的输精管可分为近端、中段、远端输精管及壶腹四部分。输精管壁的本结构相似，分泌细胞的结构及分泌活动有较大的差别。精管自中段膨大部开始管腔逐渐被一隔膜分为大小不等的两部分，较大的腔内充满了很多精子，输精管较小的腔内充满胶体状物质。中国对精子细胞在精巢内产生，在两条输精管内渐发育成熟，经过细胞质的变化并与精子外部进行物质交换，形成顶体、亚顶体、棘突。核的变化则经历了染色质的解凝和核膜的消失，最后形成成熟的精子。对鹰爪虾精子的形成过程及精子的形态结构特征进行，结果表明鹰爪虾精子细胞产生于精巢的生精小管，在输精管内进一步发育，逐渐形成成熟的精子，许多精子在输精管内聚集成团外包胶质膜，形成许多大小不一的精子囊。精子由体 及棘突两部分组成，入海水中不运动。电镜下可见体部包括核区及细胞质区两部分。核区位于精子中部，核内由均质解凝的细胞核，外包一薄层细胞质带。细胞质区比核区略小，末端变尖，细胞质区内含有大量囊泡及膜层体。棘突从体部前端斜向伸出，由许多纤丝平行紧密排列组成，外包质膜。雄虾精子囊中的精子与已交配雌虾纳精囊内的精子在形态结构上没有明显差别。对中国对虾及鹰爪虾的纳精囊及精子的贮存特征进行研究。中国对虾及鹰爪虾的纳精囊都是封闭型纳精囊，中国对虾的纳精囊腔，表面为两个对称的半圆形甲壳版所覆盖，囊内由前向后伸出三个锥状突起。鹰爪纳精表面为前后两个甲壳版所覆盖。纳精囊中部为单一的腔，向后部两侧呈管状延伸，末端膨大形成两个袋状囊，内部贮存精子囊。纳精囊从功能上分为三个部分，即纳精囊中部的开口，交配时为胶体物质所充塞；内部的囊腔为贮存精子的部位；前端的开口为产卵时精释放口。中国对虾及鹰卵子具有相似的激活和卵裂过程。卵子可以不受精子的激活，只受海水刺激即可发生皮层反应；先排出皮质棒或皮质囊泡，形成胶质层，进而释放出皮层颗粒，形成孵化膜。中国对虾的孵化膜在卵子表面形成以后再举起；鹰爪虾的孵化膜远离卵子表面形成，然后进一步举起，鹰爪虾卵周隙较大。发生皮层反应的过程中，减数分裂重新启动，排出第一极体和第二极体。中国对虾与鹰爪虾卵子的皮层反应和减数分裂都可由海水刺激而进行，与受精与否无关，但未受精卵不能分裂或公分裂为大小不等的子细胞。中国对虾与鹰爪虾受精卵都具有原始的螺旋卵裂的特性。对海水中的Mg~(2+)、 Ca~(2+)、 K~+及胰蛋白酶和胰蛋白酶抑制剂对中国对虾卵子激活的影响进行研究。结果表明海水中的Mg~(2+)对中国虾卵子的激活是必须的，Ca~(2+)、 K~+是非必须的，而且它们对受精卵和非受精卵都具有相同的作用。胰蛋白酶（0．1％）在卵子产出后可以破坏胶质层及孵化膜的形成并影响受精卵的正常卵裂。胰蛋白酶抑制剂（0．01％）可以完全抑制卵子的激活及受精，也可以使发生皮层反应的卵子处于停滞状态。卵子产出后30min胰蛋白酶及胰蛋白酶抑制剂对卵子失去作用，表明胶膜及孵化膜完全形成后具有抵抗胰蛋白酶及胰蛋白酶抑制剂的作用。

Factors influencing hemolytic activity of venom from the jellyfish Rhopilema esculentum Kishinouye

In this study, hemolytic activity of venom from the jellyfish Rhopilema esculentum Kishinouye and some factors affecting it were assayed. The HU50 of R. esculentum full venom (RFV) against chicken erythrocytes was 3.40 mu g/ml and a Hill coefficient value was 1.73 suggesting at least two molecules participated in hemolytic activity. The hemolytic activity of RFV was affected by some chemical and physical factors such as divalent cations, EDTA, (NH4)(2)SO4, pH and temperature. In the presence of Mg2+, Cu2+, Zn2+, Fe2+, Ca2+ ( >= 2 mM), Mn2+ (>= 1 mM), EDTA (>= 2 mM) and (NH4)(2)SO4, the hemolytic activity of RFV was reduced. RFV had strong hemolytic activity at the pH 6-10 and the hemolytic ratios were 0.95-1.19. Hemolytic activity was temperature-sensitive and when RFV was pre-incubated at temperatures over 40 degrees C, it was sharply reduced. (c) 2007 Elsevier Ltd. All rights reserved.

Partial characterization of the hemolytic activity of the nematocyst venom from the jellyfish Cyanea nozakii Kishinouye

Using a recently developed technique to extract jellyfish venom from nematocysts, the present study investigated the hemolytic activity of Cyanea nozakii Kishinouye nematocyst venom on chicken erythrocytes. Venom extract caused a significant concentration-dependent hemolytic effect. The extract could retain its activity at -80 degrees C but was unstable when kept at 4 degrees C and -20 degrees C for 2 days. The hemolytic activity was inhibited by heating within the range of 37-100 degrees C. The extract was active over a pH range of 5.0-8.63 and the pH optima for the extract was 7.8. Incubation of the venom with sphingomyelin specially inhibited hemolytic activity by up to 70%. Cu2+ and Mn2+ greatly reduced the hemolytic activity while Mg2+, Sr2+ and Ba2+ produced a relatively low inhibiting effect on the hemolytic activity. Treatment with Ca2+ induced a concentration-dependent increase in the hemolytic activity. In the presence of 5 mM EDTA, all the hemolytic activity was lost, however, the venom containing 1.5 mM EDTA was stable in the long-term storage. PLA(2) activity was also found in the nematocyst venom of C. nozakii. These characteristics provide us a fundamental knowledge in the C. nozakii nematocyst venom which would benefit future research. (C) 2010 Published by Elsevier Ltd.

黄蘑菇的生长对草地植被及土壤的影响

研究了黄蘑菇的生长对草地植被及土壤的影响,其结果表明:1)着生黄蘑菇的区域植被具有明显的圈带状分布特点,圈上植物群落各类群分盖度总和明显高出圈外,且圈上禾本科植物增长特别明显.2)蘑菇圈上共由27种植物组成,对照组由19种植物组成.圈上植物群落物种多样性指数,均匀度指数均高于圈外,但黄蘑菇的生长对群落均匀度的影响不大.3)蘑菇圈0～10 cm土壤土层中水分、速效磷、硝态氮和氨态氮的含量明显高于圈外,但交换性Ca~(2+)、Mg~(2+) 和pH值的变化不明显,10～20 cm土层中,圈上、圈外各土壤成分均无明显差异.

碎屑锆石年龄和Nd-Hf同位素组成对扬子基底演化的制约

The South China craton was formed by the collision of the Yangtze and Cathaysia blocks during the Neoproterozoic Jiangnan orogeny (also termed as the Jingnin or Sibao orogeny in Chinese literature). Basement rocks within the Yangtze block consist mainly of Proterozoic sediments of the Lengjiaxi and Banxi Groups. U-Pb ages of detrital zircons obtained by the LA-ICP-MS dating technique imply that the deposition of the Lengjiaxi Group continued until the Neoproterozoic. The youngest detrital zircons suggest a maximum deposition age of ~830 Ma for the Lengjiaxi Group, consistent with the initiation time of the deposition of the overlying Banxi Group, likely indicating continuous deposition of these two groups and a short temporal hiatus (~10 Ma) between the Neoproterozoic sedimentary rocks distributed in the South China craton. Detrital zircons from both the Lengjiaxi and Banxi Groups have a wide range of εHf(t) values from -12 to 14.2 and a continuous Nd and Hf model age spectrum from ~820 Ma to 2200 Ma. Some grains have model ages ranging up to ca. 2.9-3.5 Ga, indicating that both juvenile mantle material and ancient crust provided sedimentary detritus. This is also consistent with the Nd isotopic signature of sedimentary rocks recorded in the Lengjiaxi Group, suggesting a back-arc tectonic setting. The Banxi Group has slightly enriched Nd isotopic signatures relative to the Lengjiaxi Group, implying a higher percentage of old continental material in the sedimentary source. Combined with previously published data, new results can help us to reconstruct the Neoproterozoic tectonic evolution of the South China craton. The age spectrum of detrital zircons and Nd-Hf isotopic composition suggests a two-stage collision: Between 1000 Ma to 870 Ma, a continental magmatic arc was build up along the eastern margin of the Yangtze block. Convergence led to continent-based back-arc extension, subsidence and formation of a back-arc basin. Detritus originating from arc-related magmatic and old basement rocks was transported into this back-arc basin resulting in formation of the Lengjiaxi Group and its equivalents. At around 870 Ma, a second (oceanic) arc was formed by extension of an inter-arc basin, subduction subsequently led to the first collision and the emplacement of the blueschist mélange. Accretion of the magmatic arc lasted until the closure of an oceanic basin between the Yangtze and Cathaysia blocks at about 830 Ma. Shortly after the collision, subsequent uplift, further extension of the former back-arc basin and post-collisional granitoid magmatism caused a tilting of the Lengjiaxi sediments. Between 830 Ma and 820 Ma, subsequent closure of the oceanic back-arc basin and formation of the Jiangnan orogen took place, leaving a regional unconformity above the Lengjiaxi Group. Above this unconformity the Banxi Group was immediately deposited during the post-tectonic stage.