Dissection and localization of the immunostimulating domain of Edwardsiella tarda FliC

Bacterial flagellin is known to induce potent immune response in vertebrate systems via the toll-like receptor (TLR) 5. As a result, flagellin has been studied extensively as a vaccine adjuvant. In a previous study, we examined the vaccine and adjuvant potentials of the flagellin (FliC) of the fish pathogen Edwardsiella tarda. We found that E. tarda FliC induced low protective immunity by itself but could function as a molecular adjuvant and potentiate the specific immune response induced by the E. tarda antigen Eta6. Since FliC is a large protein and organized into distinct structural domains, we wondered whether the immunostimulating effect observed with the full-length protein could be localized to a certain region. To investigate this question, we in the present study dissected the FliC protein into several segments according to its structural features: (i) N163, which consists of the conserved N-terminal 163 residues of FliC; (ii) M160, which consists of the variable middle 160 residues; (iii) C94, which consists of the conserved C-terminal 94 residues; (iv) NC257, which is an artificial fusion of N163 and C94. To examine the adjuvanticity of the FliC fragments, DNA vaccine plasmids expressing FliC fragments in fusion with Eta6 were constructed and used to immunize Japanese flounder. The results showed that N163 produced the best adjuvant effect, which, in respect to improvement in the relative percent survival of the vaccinated fish, was comparable to that of the full-length FliC. None of the other FliC fragments exhibited apparent immunopotentiating effect. Further analysis showed that N163 enhanced the production of serum specific antibodies and, like full-length FliC, significantly upregulated the expression of the genes that are possibly involved in innate and adaptive immunity. These results indicate that N163 is the immunodominant region of FliC and suggest that E. tarda FliC may induce immune responses in Japanese flounder via mechanisms alternative to that involving TLR5. (C) 2010 Elsevier Ltd. All rights reserved.

Isolation and characterization of the oxygen-evolving photosystem II complex from the economical red alga Bangia fusco-purpurea

The highly pure and active photosystem II (PSII) complex was isolated from Bangia fusco-purpurea (Dillw) Lyngb., an important economic red alga in China, through two steps of sucrose density gradient ultracentrifugation and characterized by the room absorption and fluorescence emission spectra, DCIP (2,6-dichloroindophenol) reduction, and oxygen evolution rates. The PSII complex from B. fusco-purpurea had the characteristic absorption peaks of chlorophyll (Chl) a (436 and 676 nm) and typical fluorescence emission peak at 685 nm (Ex = 436 nm). Moreover, the acquired PSII complex displayed high oxygen evolution (139 mu mol O-2/(mg Chl h) in the presence of 2.5 mM 2,6-dimethybenzoqinone as an artificial acceptor and was active in photoreduction of DCIP (2,6-dichloroindophenol) by DPC (1,5-diphenylcarbazide) at 163 U/(mg Chl a h). SDS-PAGE also suggested that the purified PSII complex contained four intrinsic proteins (D1, D2, CP43, and CP47) and four extrinsic proteins (33-kD protein, 20-kD protein, cyt c-550, and 14-kD protein).

Development of expressed sequence tags from the bay scallop, Argopecten irradians irradians

The bay scallop, Argopecten irradians irradians, introduced from North America, has become one of the most important aquaculture species in China. Inan effort to identify scallop genes involved in host defense, a high-quality cDNA library was constructed from whole body tissues of the bay scallop. A total of 5828 successful sequencing reactions yielded 4995 expressed sequence tags (ESTs) longer than 100 bp. Cluster and assembly analyses of the ESTs identified 637 contigs (consisting of 2853 sequences) and 2142 singletons, totaling 2779 unique sequences. Basic Local Alignment Search Tool (BLAST) analysis showed that the majority (73%) of the unique sequences had no significant homology (E-value >= 0.005) to sequences in GenBank. Among the 748 sequences with significant GenBank matches, 160 (21.4%) were for genes related to metabolism, 131 (17.5%) for cell/organism defense, 124 (16.6%) for gene/protein expression, 83 (11.1%) for cell structure/motility, 70 (9.4%) for cell signaling/communication, 17 (2.3%) for cell division, and 163 (21.8%) matched to genes of unknown functions. The list of host-defense genes included many genes with known and important roles in innate defense such as lectins, defensins, proteases, protease inhibitors, heat shock proteins, antioxidants, and Toll-like receptors. The study provides a significant number of ESTs for gene discovery and candidate genes for studying host defense in scallops and other molluscs.

The effect of acute salinity change on white spot syndrome (WSS) outbreaks in Fenneropenaeus chinensis

In order to observe the effect of salinity on disease resistance and white spot syndrome virus (WSSV) proliferation in Fenneropenaeus chinensis, shrimps with latent WSSV were subjected to two acute salinity changes from the original salinity of 22 ppt to 18 and 14 ppt in an hour, respectively. The total haemocyte count (THC) of the challenged group showed no evident change under salinity adjustments, but the phenoloxidase (PO) index declined significantly (P<0.05) corresponding to continuing acute salinity changes from the 24th to the 72nd hour. According to the WSSV load detected by quantitative real-time PCR method, it was found that WSSV carried by the challenged group and control group were significantly different (P<0.05); acute salinity change from 22 to 14 ppt led to the WSSV carried in the challenged group being significantly higher (P<0.05) than that of those surviving in 22 ppt, but salinity change from 22 to 18 ppt had no such effect. At the end of the 72-h experiment, the challenged group subjected to salinity change from 22 to 14 ppt had nearly 3 times the WSSV load as the control group with no salinity change. Therefore, salinity changes over a particular range could result in a decrease of immunocompetence and obvious WSSV proliferation in the shrimps, leading to white spot syndrome developing from a latent infection to an acute outbreak. (C) 2005 Elsevier B.V All rights reserved.

Antimicrobial activity of hydroxylbenzenesulfonailides derivatives of chitosan, chitosan sulfates and carboxymethyl chitosan

Chitosan, carboxymethyl chitosan (CIVICS) and chitosan sulfates (CSS) with different molecular weight were modified by reacting with 4-hydroxyl-5-chloride-1,3-benzene-disulfo-chloride or 2-hydroxyl-5-chloride-1,3 -benzene-disulfo-chloride to give 12 kinds of new hydroxylbenzenesulfonailides derivatives of them. The preparation conditions of the derivatives were discussed in this paper, and their structures were characterized by FT-IR and C-13 NMR spectroscopy. The solubility of the derivatives was measured in the experiment. In addition, their antimicrobial activities against four bacteria and five crop-threatening pathogenic fungi were tested in the experiment. Besides, the rule and mechanism of their antibacterial activities were discussed in this paper. (C) 2009 Published by Elsevier B.V.

Low-temperature molten salt synthesis and characterization of CoWO4 nano-particles

CoWO4 nano-particles were successfully synthesized at a low temperature of 270 degrees C by a molten salt method, and effects of such processing parameters as holding time and salt quantity on the crystallization and development Of CoWO4 crystallites were initially studied. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM). and photoluminescent spectra techniques (PL), respectively. Experimental results showed that the well-crystallized CoWO4 nano-particles with ca. 45 nm in diameter could be obtained at 270 degrees C for a holding time of 8 h with 6:1 mass ratio of the salt to CoWO4 precursor, and XRD analysis evidenced that the as-prepared sample was a pure monoclinic phase Of CoWO4 with wolframite structure. Their PL spectra revealed that the CoWO4 nano-particles displayed a very strong PL peak at 453 nm with the excitation wavelength of 230 nm, and PL properties of CoWO4 crystallites relied on their crystalline state, especially on their particle size. (C) 2009 Elsevier B.V. All rights reserved.

高寒草甸土地退化及其恢复重建对植被碳、氮含量的影响

以青海省达日县高寒草甸原生高寒嵩草（Kobresia）草甸封育系统为对照,研究了土地退化对植被生产力的影响,检验了不同人工重建措施（两个人工种植处理：混播（HB）、翻耕单播（DBF）和1个退化草地封育自然恢复处理（NR）及1个退化草地自然状态（SDL））对植被生产力的相对影响程度。结果表明,原生植被封育处理（YF）地上总生物量为265.1g•m~(-2),混播（HB）和翻耕单播（DBF）处理中地上总生物量分别为原生植被封育处理的116%和68%。退化草地封育自然恢复处理（NR）和重度退化自然状态下地上总生物量分别为原生植被封育的76%和53%。YF处理根系生物量远大于其它处理。原生植被封育系统中植被地上部分碳储量为110.14g•m~(-2),地下根系（0～30cm）碳储量为2957g•m~(-2),植被总碳储量为3067.14g•m~(-2);重度退化草地系统中植被地上部分碳储量为57.07g•m~(-2),地下根系（0～30cm）碳储量为357g•m~(-2),植被总碳储量为414.07g•m~(-2)。由此可见,高寒草甸严重退化后,通过植物组织流失的碳达到2653.35g•m~(-2),即86.5%的碳损失;原生植被封育系统植被总氮储量为56.85g•m~(-2),而重度退化草地植被总氮储量为18.02g•m~(-2),高寒草甸严重退化使植物组织68.30%氮损失。与重度退化地相比,由于恢复重建措施增加了植物的生物量输入和群落组成,除翻耕单播处理外,其它恢复重建措施均能恢复系统植被的碳氮储量。这些恢复重建措施将会逐步改善土壤的物理和化学特性,最终使这些生态系统逐步由碳源向碳汇方向的转变成为可能。

二叶獐牙菜化学成分研究

从二叶獐牙菜(Swertia bifolia Batal.)的全草中分离得到了7个化合物,5种口山酮和2种甾醇类化合物.它们的结构经光谱方法分别鉴定为1-羟基-3,5-二甲氧基口山酮(Ⅰ)、1-羟基-3,7,8-三甲氧基口山酮(Ⅱ)、1,8-二羟基-3,5-二甲氧基口山酮(Ⅲ)、1,8-二羟基-3,7-二甲氧基口山酮(Ⅳ)、1,7-二羟基-3,8-二甲氧基口山酮(Ⅴ)、β-谷甾醇(Ⅵ)、胡萝卜苷(Ⅶ).

植物繁育系统研究的最新进展和评述

植物繁育系统是当今进化生物学研究中最为活跃的领域。繁育系统是指代表所有影响后代遗传组成的有性特征和总和，主要包括形态特征、花的开放式样，花各部分的寿命、传粉者种类和频率，自交亲和程度和交配系统，其中酱系统是核心，我们重点综述了植物有性繁育系统研究中1）传粉模式的多样性，2）从历史发生角度利用系统发育方法检验花性状的演化和繁育系统的生态转变过程；3）近交衰退对植物生殖史的影响及其机制和4）混和交配系统的时空动态，维持机理以及进化趋势的最新研究结果。总结了繁育系统在研究花适应性，物种形成机制和濒危植物保护生物学中的重要作用。最后对今后的繁育系统研究提出了两点建议：1）正确理解和使用适应概念，更多地利用人工控制实验来检验花的适应价值和2）将分子技术和生态学结合起来，开展群落水平和种以上水平的繁育系统研究，比较驱动与传粉多样性密切相关的花多样性基因和自花，异花传粉基因的进化与分化。确定繁育系统相互作用中的关键因子。

珠毛蟹甲草的大小孢子发生及雌雄配子体发育

珠毛蟹甲草 ( Parasenecio roborowskii)是菊科千里光族中款冬亚族蟹甲草属的一种植物 ,在藏药上全草入药 ,有治疗哮喘等疾病之功效。本文首次观察了珠毛蟹甲草的大小孢子发生、雌雄配子体的发育 ,旨在为开发与利用该种植物提供有性生殖过程方面的基础资料。

新疆细毛羊超排胚胎移植核心群育种方案的确定

南山种羊场的育种方案是根据育种目标的4个选择标准，加权综合而形成。计算出的选择指数为：净毛质量＋21.08；毛束长度＋0.58；平均纤维直径-4．23；育成羊体质量＋1.47。估测该方案每世代遗传进展为1.6～2.1，选择指数标准差依MOET功率而定，与传统的育种改良方案（每世代遗传进展约为选择指数标准差）相比非常有益。

Digestibility, nutrient balance and urinary purine derivative excretion in dry yak cows fed oat hay at different levels of intake

A feeding trial A as conducted at the farm of Qinghai Academy of Animal and Veterinary Science, Xining, China during 1996 - 1997 with three dry yak cows (initial body weight 163 - 197 kg, age 5 - 6 years) by using 3 x 3 Latin Square Design to determine the effect of levels of feed intake on digestion, nitrogen balance and purine derivative excretion in urine of yak cows. The animals were fed oat hay (nitrogen 13.5 g/kg dry matter (DM), metabolisable energy 8.3 MJ/kg DM), i.e., 0.3, 0.6 and 0.9 of voluntary intake (VI). Each intake treatment lasted for 17 days and the samples (feeds, faeces and urine) were collected during last 7 days of each period. The results indicate that digestibility of dietary DM, OM, NDF and ash declined when intake levels increased from 0.3 to 0.9 VI [DM, from 66.1% to 59.1% (P < 0.05); OM, from 68.1% to 59.9% (P < 0.05); NDF, from 62.1% to 54.3% (P < 0.05); and ash, from 33.9% to 11.8% (P < 0.05)]. Around 0.10 g N/kg W-0.75 was deficient daily in yak cows at 0.3 VI, and positive N balances were observed at 0.6 and 0.9 VI. Intake levels significantly (P < 0.05) affected total PD excretion in yak urine. The proportion of allantoin increased (P < 0.05) and uric acid decreased (P < 0.05) as intake level of feed increased. (C) 2004 Elsevier B.V. All rights reserved.

原子力显微镜Tapping模式探针动力学与操作方法研究

自从1986年G. Binnig 等发明原子力显微镜(AFM)以来，纳米科技研究得到了快速发展，纳米科技研究的最终目标是从纳米甚至分子与原子尺度上制造功能器件或系统，而实现此目标的手段之一是研制能够在纳米尺度上进行精确可控操作的装置、方法与技术。对此，学者们对基于 AFM 的纳米操作进行了大量研究。基于AFM-Tapping模式的纳米观测与操作具有成本低、易实现性等特点，因而近年来成为纳米技术研究的热点。但基于AFM探针的纳米观测和操作的基本理论仍然很不完善，许多情况下缺乏基于探针观测与操作的纳观作用力的合理解释与描述，因此限制了基于探针的纳米技术发展。为了解决这一问题，本论文在国家自然科学基金项目“基于机器人化的纳米操作方法研究(60575060)”的支持下，广泛收集和查阅国内外相关资料，重点开展了AFM-Tapping模式下探针动力学解释方法与建模研究，并进行了基于AFM-Tapping的纳米操作方法研究。主要研究工作如下： 1)针对探针动力学建模问题，开展了基于Hamilton原理和变分原理的有边界条件的探针一维悬臂梁建模方法研究。利用模态叠加法和模态函数正交性对探针各阶模态进行了解耦分析，得到了解耦的探针动力学方程。 2)开展了纳观尺度下探针-样品作用力研究。分析与阐述了毛细力、接触力和摩擦力等纳观尺度作用力；开展了基于Lennard-Jones势模型的不同形状探针与样品间的相互作用势描述方法研究；并根据势能-力之间的关系，研究了可描述半球形探针与样品间相互作用力的数学表达式。 3)开展了基于弹簧振子模型的纳观非线性力作用下探针振动问题分析研究。首次提出了基于探针弹性力与非线性纳观力平衡关系的探针振动状态区域划分方法。在探针振动能量平衡分析的基础上，研究了AFM-Tapping模式中的双稳态现象，进而得到了描述双稳态现象的解析表达式。最后采用Lyapunov指数分析的方法，证明了探针在非线性振动中确实存在着混沌现象。 4)研究了基于AFM-Tapping模式的纳米操作方法。通过研究探针振幅调节控制和预编程作业轨迹规划策略，提出了一种具有增强探针概念的纳米作业方法。该方法可以在参数设定和预编程条件下自动完成纳米尺度的平移和旋转操作，从而可以大大提高纳米操作的效率和精度。实验结果验证了该方法的有效性。本文的工作为纳米操作方法的研究提供了可以借鉴的理论与实验经验，有助于推动基于AFM的纳米操作与制造技术的发展。