Synthesis and extraction of lanthanofullerenes and its DEIMS, ESR characterizations

The synthesis for lanthanofullerenes was studied by activating the La2O3 containing graphite rod in situ and back-burning the carbide-rich cathode deposite, La@C-2n are efficiently extracted in high temperature toluene, among them, La@C-74 as a new species is added into the soluble lanthanofullerenes, The toluene extraction is first characterized by desorption electron impact (DEI) mass spectrometry, The ESR spectrum of the extraction at room temperature is also discussed.

Molecular characterizations of oxytetracycline resistant bacteria and their resistance genes from mariculture waters of China

Oxytetracycline-resistant bacteria were isolated from a mariculture farm in China, and accounted for 32.23% and 5.63% of the total culturable microbes of the sea cucumber and the sea urchin rearing waters respectively. Marine vibrios, especially strains related to Vibrio splendidus or V. tasmaniensis, were the most abundant resistant isolates. For oxytetracycline resistance, tet(A), tet(B) and tet(D) genes were detected in both sea cucumber and sea urchin rearing ponds. The dominant resistance type for V. tasmaniensis-like strains was the combination of both tet(A) and tet(B) genes, while the major resistance type for V. splendidus-like strains was a single tet(D) gene. Most of the sea cucumber tet-positive isolates harbored a chloramphenicol-resistance gene, either cat IV or cat II, while only a few sea urchin tet-positive isolates harbored a cat gene, actually cat IV. The coexistence of tet and cat genes in the strains isolated from the mariculture farm studied was helpful in explaining some of the multi-resistance mechanisms. (c) 2006 Elsevier Ltd. All rights reserved.

Molecular characterizations of chloramphenicol- and oxytetracycline-resistant bacteria and resistance genes in mariculture waters of China

In order to gain an understanding of the diversity and distribution of antimicrobial-resistant bacteria and their resistance genes in maricultural environments, multidrug-resistant bacteria were screened for the rearing waters from a mariculture farm of China. Both abalone Haliotis discus hannai and turbot Scophthalmus maximus rearing waters were populated with abundant chloramphenicol-resistant bacteria. These bacteria were also multidrug resistant, with Vibrio splendidus and Vibrio tasmaniensis being the most predominant species. The chloramphenicol-resistance gene cat II, cat IV or floR could be detected in most of the multidrug-resistant isolates, and the oxytetracycline-resistance gene tet(B), tet(D), tet(E) or tet(M) could also be detected for most of the isolates. Coexistence of chloramphenicol- and oxytetracycline-resistance genes partially explains the molecular mechanism of multidrug resistance in the studied maricultural environments. Comparative studies with different antimicrobial agents as the starting isolation reagents may help detect a wider diversity of the antimicrobial-resistant bacteria and their resistance genes. (C) 2009 Elsevier Ltd. All rights reserved.

Characterizations and activities of the nano-sized Ni/Al2O3 and Ni/La-Al2O3 catalysts for NH3 decomposition

A series of nano-sized Ni/Al2O3 and Ni/La-Al2O3 catalysts that possess high activities for NH3 decomposition have been successfully synthesized by a coprecipitation method. The catalytic performance was investigated under the atmospheric conditions and a significant enhancement in the activity after the introduction of La was observed. Aiming to study the influence of La promoter on the physicochemical properties, we characterized the catalysts by N-2 adsorption/desorption, XRD, H-2-TPR, chemisorption and TEM techniques. Physisorption results suggested a high specific surface area and XRD spectra showed that nickel particles are in a highly dispersed state. A combination of XRD, TEM and chemisorption showed that Ni-0 particles with the average size lower, than 5.0 nm are always obtained even though the Ni loading ranged widely from 4 to 63 %. Compared with the Ni/Al2O3 catalysts, the Ni/La-Al2O3 ones with an appropriate amount of promoter enjoy a more open mesoporous structure and higher dispersion of Ni. Reduction kinetic studies of prepared catalysts were investigated by temperature-programmed reduction (TPR) method and the fact that La additive partially destroyed the metastable Ni-Al mixed oxide phase was detailed. (c) 2005 Elsevier B.V. All rights reserved.

Investigations of cohesive zone properties of the interface between metal film and ceramic substrate at nano- and micro-scales

Cohesive zone characterizations of the interface between metal film and ceramic substrate at micro- and nano-scales are performed in the present research. At the nano-scale, a special potential for special material interface (Ag/MgO) is adopted to investigate the interface separation mechanism by using MD simulation, and stress-separation relationship will be obtained. At the micro-scale, peeling experiment is performed for the Al film/Al2O3 substrate system with an adhesive layer at the interface. Adhesive is a mixture of epoxy and polyimide with mass ratio 1:1, by which a brittle cohesive property is obtained. The relationships between energy release rate, the film thickness and the adhesive layer thickness are measured during the steady-state peeling. The experimental result has a similar trend as modeling result for a weak adhesion interface case.

Low-temperature hydrothermal growth of oriented [0001] ZnO film

Well-aligned ZnO films have been successfully prepared by using low-temperature hydrothermal approach on (0001) sapphire substrates that were pre-coated with a ZnO nano-layer by dip-coating. The characterizations of scanning electron microscopy (SEM) and X-ray diffraction (XRD) indicate that the ZnO films consist of hexagonal rods that grow along the c axis based on the sapphire substrates. It is found that the size of ZnO rods can be adjusted by an aqueous solution with some methenamine. (c) 2006 Elsevier B.V. All rights reserved.

转Rubisco 活化酶大型同工酶基因(rca)水稻的光合作用特性研究

Rubisco 是催化光合暗反应第一步反应的酶，是唯一能将CO2 转变成碳水化合物的酶，由它固定和最后转化成的碳水化合物提供了植物、动物和微生物的食物和能量。但是，Rubisco 催化该反应的效率十分低，使之成为光合作用的限速步骤。由于Rubisco 的合成和催化过程十分复杂，人们很难通过直接改造Rubisco 提高植物固定CO2 的能力。而Rubisco 活化酶能活化Rubisco，使植物在生理CO2 浓度下具有最大的CO2 同化速率，因此研究活化酶有重要意义。水稻活化酶有2 个同工酶，大型同工酶比小型同工酶C 端多37 个氨基酸，其中包括两个Cys 残基。这两个Cys 残基的存在使活化酶大型同工酶对ADP 的存在更加敏感，其活性在硫氧还蛋白的介导下能被基质中氧化还原状态的变化所调节。由于活化酶大型同工酶对调节Rubisco 的活性具有的这种特殊作用，在本研究中，将活化酶大型同工酶rca基因用正义和反义引入水稻基因组，获得了过量表达活化酶大型同工酶基因和反义抑制活化酶基因表达的转基因植株，对其光合作用进行了生理和生化分析。 本研究的主要结果如下： Rubisco 活化酶大型同工酶基因的克隆：从水稻镇恢249 中克隆了1525 bp 的活化酶大型同工酶cDNA 序列。经过测序，它与报道的粳稻品种活化酶大型同工酶cDNA 序列（rca）完全相同。 构建了4 个植物表达载体：3 个为过量表达rca的载体，分别是pCBUbirca，pCBSrca 和 pCBSUbirca ，其中rca分别在水稻中高效表达的玉米Ubiquitin 启动子、受光调控的Rubisco 小亚基基因启动子和由这两个启动子构成的双启动子控制下表达; 1 个在Ubiquitin 启动子控制的反义rca载体，即 pCBUbi-antirca。 获得了转化rca的水稻再生植株：用日本晴，台北309，武育梗7 号和籼稻品种培矮64S 水稻成熟种子诱导愈伤组织。用改良的农杆菌浸染法将rca基因转化这些愈伤组织，在潮霉素筛选压力下获得抗性愈伤组织，经过2 天的干燥处理后，转入到含山梨醇的高渗分化培养基上培养，能迅速获得大量的芽和转化体再生植株。 获得了转rca基因的水稻植株：抗性愈伤组织和再生水稻幼苗的叶片经GUS 染色呈蓝黑色。PCR 扩增转基因水稻基因组内的潮霉素基因和rca，大部分转基因水稻中含有841 bp 的潮霉素基因片段和1525 bp 长的rca cDNA 片段。251 粒T1 代转基因水稻种子中189粒呈现潮霉素抗性，抗性种子/非抗性种子的比率约为3：1，接近孟德尔分离规律。Southern杂交表明rca序列已整合到水稻基因组，一般含1－2个拷贝。Western 杂交显示Rubisco 活化酶含量在转pCBUbi －antirca 的水稻中和对照比，几乎看不出，被反义抑制;转pCBUbirca 的水稻与对照含量相差无几;转pCBSUbirca，pCBSrca 载体的水稻中活化酶的含量比对照有极显著的增加。 T1 代转rca水稻的光合作用发生显著变化：转pCBSrca 和pCBSUbirca 的水稻在饱和光强下的Rubisco 初始活性、羧化效率、光合速率都明显高于对照，但是表观量子效率、色素含量和Rubisco 总活性与对照相似。两者相比，前者比后者更高;转反义rca（pCBUbi-antirca）基因的水稻饱和光强下的光合速率、表观量子效率、羧化效率、Rubisco 初始活性明显降低，色素含量和Rubisco 总活性基本不变;转pCBUbirca 的水稻中，光合作用的各项参数与对照基本相似。 T1 代转rca水稻的叶绿素荧光明显改变：转pCBSrca 和pCBSUbirca 的水稻ΦPSII 的值明显高于对照，而且前者qP 的值明显高于对照。两者相比，前者的ΦPSII 和qP 的值比后者高;转反义rca的水稻ΦPSII，F′v/F′m，qP 值和对照比都明显降低，但qN 的值升高;转pCBUbirca 载体的水稻中，叶绿素荧光的各项参数与对照基本相似。 转rca基因的水稻生长发育的变化：转pCBUbirca 载体的水稻整个生长发育过程与对照相似;转化pCBSrca 和pCBSUbirca 载体的水稻和对照比，植株高大，生长发育速度加快，抽穗、开花和结籽的时间提前。两者本身相比，前者比后者明显;转反义rca（pCBUbi-antirca）基因的水稻生长发育延迟，植株矮小，种子败育。 由上可见，Rubisco 活化酶大型同工酶rca基因在Rubisco 小亚基基因启动子、Ubiquitin 基因启动子和Rubisco 小亚基基因启动子共同控制下正义转入水稻的转基因植物光合作用的参数最好，光合效率提高，植物表型最好，生长发育加快，提前开花结籽。这一研究可能为获得高光合效率和高产量的水稻奠定了基础。

蕨类植物铁芒萁（Dicranopteris dichotoma）体内稀土元素的分布及其光合特性的研究

为了阐明蕨类植物铁芒萁(Dicranopteris dichotoma Bernh.)体内稀土元素的分布及其光合特性，采用电感耦合等离子质谱分析了中国江西省龙南县轻、重稀土矿区和非矿区铁芒萁植物体内的稀土元素含量，并采用透射电子显微镜对其叶片细胞内的稀土元素进行精确定位。还比较系统的研究了自然条件下的铁芒萁与高浓度稀土元素处理条件下的非稀土元素富集植物黄瓜(Cucumis sativus Linn)的光合特性。结果表明： 1、0.5 mmol•L-1 LaCl3处理黄瓜后，可以诱导激发能向PS II分配。1和2 mmol•L-1 LaCl3处理黄瓜后，对黄瓜幼苗抑制作用表现在对其生长率，光合放氧活性和叶绿体完整率的抑制。这是由于LaCl3对黄瓜细胞结构和叶绿体膜结构的破坏所致。其表现为对类囊体膜结构的破坏，而导致PS II光合活性下降，并最终抑制黄瓜生长。 2、铁芒萁可以富集稀土元素，轻、重稀土矿区铁芒萁植物稀土元素的分布规律为叶片>根>土壤>茎>叶柄，非矿区铁芒萁植物稀土元素的分布规律为叶片>根>茎>叶柄。稀土元素在铁芒萁体内的运输和迁移过程中，发生了明显的分异作用，茎、叶柄、叶片中的重稀土相对贫乏，叶片中可以富集高浓度的轻稀土元素。 3、稀土元素可以进入完整的铁芒萁表皮细胞和叶肉细胞中，但多以沉淀的形式聚集在一起。非矿区铁芒萁叶绿体中的稀土元素含量约占其叶片中含量的5％。轻稀土矿区铁芒萁叶绿体中的稀土元素含量约占其叶片中含量的10％。部分稀土元素定位于富含PS II的基粒片层上。 4、铁芒萁富集稀土元素受环境和遗传特性的双重影响，但主要由其自身的生理、生化特性决定。其富集稀土元素的机制是隔离稀土元素在细胞壁、液泡中和分泌结合物质使稀土元素成为沉淀沉积下来，从而避免对光合活性的破坏。 5、与非矿区铁芒萁相比，轻稀土矿区植物叶绿体膜的全链电子传递速率增加了34.9％，PS II的电子传递活性增高了252.9％，PS I的电子传递活性增加了16.8％。轻稀土矿区铁芒萁全链电子传递活性的增加主要来自PS II电子传递活性的大幅提高，这可能与其调节激发能更多向PS II分配，提高PS II反应中心色素蛋白复合体（67.0％）和捕光色素蛋白复合体的含量相关。 6、与非矿区铁芒萁相比，重稀土矿区植物叶绿体膜的全链电子传递速率增加了46.3％，PS II的电子传递活性增高了23.8％，PS I的电子传递活性增加了60.4％。重稀土矿区铁芒萁电子传递活性的提高主要来自PS I电子传递活性的大量增加，这可能与其PS I反应中心蛋白复合体含量的提高（60.0％）有关。 铁芒萁富集并吸收稀土元素主要是由自身的理化特性决定的。它能够将稀土元素以沉淀的形式固定在细胞内部，并通过改变生理代谢来避免高浓度稀土元素对其光合作用的影响。可以在治理稀土元素污染的环保工程中用作植物修复材料。

Characterization of TRPC2, an Essential Genetic Component of VNS Chemoreception, Provides Insights into the Evolution of Pheromonal Olfaction in Secondary-Adapted Marine Mammals

Pheromones are chemical cues released and sensed by individuals of the same species, which are of major importance in regulating reproductive and social behaviors of mammals. Generally, they are detected by the vomeronasal system (VNS). Here, we first investigated and compared an essential genetic component of vomeronasal chemoreception, that is, TRPC2 gene, of four marine mammals varying the degree of aquatic specialization and related terrestrial species in order to provide insights into the evolution of pheromonal olfaction in the mammalian transition from land to water. Our results based on sequence characterizations and evolutionary analyses, for the first time, show the evidence for the ancestral impairment of vomeronasal pheromone signal transduction pathway in fully aquatic cetaceans, supporting a reduced or absent dependence on olfaction as a result of the complete adaptation to the marine habitat, whereas the amphibious California sea lion was found to have a putatively functional TRPC2 gene, which is still under strong selective pressures, reflecting the reliance of terrestrial environment on chemical recognition among the semiadapted marine mammals. Interestingly, our study found that, unlike that of the California sea lion, TRPC2 genes of the harbor seal and the river otter, both of which are also semiaquatic, are pseudogenes. Our data suggest that other unknown selective pressures or sensory modalities might have promoted the independent absence of a functional VNS in these two species. In this respect, the evolution of pheromonal olfaction in marine mammals appears to be more complex and confusing than has been previously thought. Our study makes a useful contribution to the current understanding of the evolution of pheromone perception of mammals in response to selective pressures from an aquatic environment.

Plankton community composition in the Three Gorges Reservoir Region revealed by PCR-DGGE and its relationships with environmental factors

To explore the relationships between community composition and the environment in a reservoir ecosystem, plankton communities from the Three Gorges Reservoir Region were studied by PCR-denaturing gradient gel electrophoresis fingerprinting. Bacterial and eukaryotic operational taxonomic units (OTUs), generated by DGGE analysis of the PCR-amplified 16S and 18S rRNA genes, were used as surrogates for the dominant "biodiversity units". OTU composition among the sites was heterogeneous; 46.7% of the total bacteria] OTUs (45) and 64.1% of the eukaryotic OTUs (39) were identified in less than half of the sampling sites. Unweighted pair group method with arithmetic averages (UPGMA) clustering of the OTUs suggested that the plankton communities in the Xiangxi Rive sites were not always significantly different from those from the Yangtze River sites, despite clear differences in their environmental characterizations. Canonical correspondence analysis (CCA) was applied to further investigate the relationships between OTU composition and the environmental factors. The first two CCA ordination axes suggested that the bacterial community composition was primarily correlated with the variables of NO3--N, dissolved oxygen (DO), and SiO32--Si, whereas, the eukaryotic community was mainly correlated with the concentrations of DO, PO43--P, and SiO32--Si.

Field and laboratory studies on pathological and biochemical characterization of microcystin-induced liver and kidney damage in the phytoplanktivorous bighead carp

Field and experimental studies were conducted to investigate pathological characterizations and biochemical responses in the liver and kidney of the phytoplanktivorous bighead carp after intraperitoneal (i.p.) administration of microcystins (MCs) and exposure to natural cyanobacterial blooms in Meiliang Bay, Lake Taihu. Bighead carp in field and laboratory studies showed a progressive recovery of structure and function in terms of histological, cellular, and biochemical features. In laboratory study, when fish were i.p. injected with extracted MCs at the doses of 200 and 500 mu g MC- LReq/kg body weight, respectively, liver pathology in bighead carp was observed in a time dose-dependent manner within 24 h postinjection and characterized by disruption of liver structure, condensed cytoplasm, and the appearance of massive hepatocytes with karyopyknosis, karyorrhexis, and karyolysis. In comparison with previous studies on other fish, bighead carp in field study endured higher MC doses and longer-term exposure, but displayed less damage in the liver and kidney. Ultrastructural examination in the liver revealed the presence of lysosome proliferation, suggesting that bighead carp might eliminate or lessen cell damage caused by MCs through lysosome activation. Biochemically, sensitive responses in the antioxidant enzymes and higher basal glutathione concentrations might be responsible for their powerful resistance to MCs, suggesting that bighead carp can be used as biomanipulation fish to counteract cyanotoxin contamination.

Physiological comparison between colonial and unicellular forms of Microcystis aeruginosa Kutz. (Cyanobacteria)

In order to gain insight into the bloom sustainment of colonial Microcystis aeruginosa Katz., physiological characterizations were undertaken in this study. Compared with unicellular Microcystis, colonial Microcystis phenotypes exhibited a higher maximum photosynthetic rate (Pm), a higher maximum electron transfer rate (ETRmax), higher phycocyanin content, and a higher affinity for inorganic carbon (K-0.5 DIC <= 8.4 +/- 0.7 mu M) during the growth period monitored in this study. This suggests that photosynthetic efficiency is a dominant physiological adaptation found in colonial Microcystis, thus promoting bloom sustainment. In addition, the high content of soluble and total carbohydrates in colonial Microcystis suggests that this phenotype may possess a higher ability to tolerate enhanced stress conditions when compared to unicellular (noncolonial) phenotypes. Therefore, high photosynthetic activities and high tolerance abilities may explain the bloom sustainment of colonial Microcystis in eutrophic lakes.

Temperature- and salinity-dependent development of a Nordic strain of Ichthyophthirius multifiliis from rainbow trout

During the twentieth century evidence was presented which suggested the presence of various strains and races of the parasite Ichthyophthirius multifiliis Fouquet. However, ecological profiles of various parasite isolates from different climatic zones are sparse. Such stringent characterizations of parasite development at defined abiotic conditions could provide valuable criteria for the different races: profile comparison from various localities is one way to differentiate these strains. Baseline investigations were therefore performed on the associations between abiotic factors (temperature/salinity) and the development of theronts in tomocysts of I. multifiliis isolated from rainbow trout in a Danish trout farm. It was shown that tomocyst formation and theront development took place between 5 and 30degreesC. Development rates and sizes of theronts were clearly affected by temperature: theronts escaped tomocysts already after 16-27 h at 25degreesC and 30degreesC, whereas this process took 8-9 days at 5degreesC. Likewise, theront size decreased steadily from a maximum of 57.4 x 28.6 mum at 5degreesC to 28.6 x 20.0 mum at 30degreesC. This size variation was only partly associated with the number of theronts that appeared at different temperatures. The lowest number of theronts escaping from one tomocyst was indeed found at 5-7degreesC (mean 329-413). At 11.6, 17.0 and 21degreesC. the highest number of theronts appeared (mean 546-642). However, at 25 and 30degreesC, the number decreased (458 and 424, respectively). Additional studies on the salinity dependent development of the parasite (at 11.6degreesC) showed that salinities above 5 p.p.t. totally inhibited development. Even at 5 p.p.t. the developmental time significantly increased and the number of theronts produced from one tomocyst decreased.