Evidence of host blood feeding by the monogenean, Ancyrocephalus mogurndae (Monogenea : Ancyrocephalidae) from the gills of the mandarin fish, Siniperca chuatsi

By examining iron contents, it is demonstrated that the monogenean Ancyrocephalus mogurndae (Yamaguti, 1940) feeds on the blood of its host, the mandarin fish Siniperca chuatsi (Basilewsky). The iron content and then the quantity of blood necessary to produce this amount of iron are found different in young and fully-matured worms. Young worms contain higher levels of iron and estimated amount of blood. It is suggested that A. mogurndae may start to feed on host blood as attached on gills, and the amount of blood ingested by young worms may vary from 0.01 to 1.00 mu l before reproduction. The difference between young and fully-matured worms may be accounted for by the elimination of haematin and change of food composition in matured worms and may also be affected by reproduction. Experimental infections of the monogenean may provide supportive information for explaining the difference, and further studies should also examine the effect of immune components in host blood ol mucus on the intestines of the parasite.

Long-term changes in crustacean zooplankton and water quality in a shallow, eutrophic Chinese lake densely stocked with fish

From surveys made in 1962-1963, 1973-1974, 1979-1996 at two Stations in Lake Donghu, a shallow eutrophic water body near Wuhan, P. R. China, the authors, derive long-term changes in species composition, standing crop and body-size of planktonic crustaceans. The species number decreased from the 1960s to the 1990s. The cladocerans dropped from 46 (1960s) to 26 (1980s) to 13 (1990s); the copepods decreased from 14 (1960s) to 10 (1980s) to 7 (1990s). From the mid-1980s on, the dominant crustaceans also changed: Daphnia hyalina and D. carinata ssp. were replaced by Moina micrura and Diaphanosoma brachyurum at Stations 1 and 2, respectively; Cyclops vicinus replaced Mesocyclops leuckarti. Densities and biomass of Cladocera decreased markedly after 1987. Annual average densities and biomass of cladocerans were statistically differences between 1962-1986 and 1987-1996 (P < 0.01). Annual average densities of Daphnia (Station 1 + Station 2) were negatively correlated with fish yield. Since the 1980s, annual average body length of Cladocera and Calanoida decreased, while annual average body length of Cyclopoida increased. In the same years, average body length of copepods was lower during May-October than during January-April and November-December. A 12-yr data analysis showed annual average concentration of chlorophyll-a (Chl-a) to be negatively correlated with annual average density of Daphnia, whilst lake transparency was positively correlated with annual average densities of Daphnia. The results imply that, since Daphnia feeds efficiently on phytoplankton, it could decrease concentration of Chl-a, and enhance water transparency.

基于SPEM2XPDL模型转换的软件过程执行

SPEM(software process engineering metamodel)是国际标准化组织制定的标准元模型,正日益成为软件过程建模领域的行业标准,但在过程执行方面,SPEM还存在不足.将软件过程看作是一种特殊的工作流,提出了一种应用工作流运行机制支持软件过程执行的方法.通过将SPEM模型转换为XPDL(XML process definition language)模型,利用XPDL引擎支持SPEM模型的执行.制定了SPEM和XPDL之间的映射规则,设计了转换算法并开发了转换引擎.该方法被应用在SoftPM项目中,成功地基于XPDL引擎Shark实现了对软件过程模型的执行支持.

SPEM2XPDL模型转换研究

将软件过程技术与工作流技术相结合,严格定义了SPEM2XPDL模型转换规则,设计并实现了一个SPEM2XPDL模型转换引擎.此引擎将SPEM描述的软件过程转换为符合工作流定义(XPDL)的工作流过程,从而可基于工作流管理系统对软件过程提供执行支持.SPEM模型经引擎转换后在工作流管理系统Shark上的成功执行表明了引擎的可用性.

姚虻成功从宿主获得血餐的分子机制初探

在长期的吸血进化过程中，吸血节肢动物在唾液腺中形成了一系列有助于适应吸 血生存的活性物质，这些物质包括血管舒张分子、血小板聚集抑制分子、抗凝血分子 和其它相互作用的分子。此外，为了得到洁净的血液和防止在吸血过程中被病原微生 物感染，吸血节肢动物在其唾液腺中形成了许多防御物质以保护自身和宿主，这些物 质包括抗菌肽和蛋白酶抑制剂等。因此，研究吸血节肢动物的唾液腺重要活性物质和 转录体组学有助于弄清其吸血机制。 姚虻（Tabancus yao Macquart）是我国特有的牛虻，其雌性在产卵前需要吸食大 型哺乳动物的血液以促使卵的发育。我们希望通过对姚虻唾液腺重要活性物质和转录 体组学的研究揭示姚虻成功从宿主获得血餐的分子机制，找到具有药用前景的活性物 质和为控制该虫及其传播的疾病的提供理论基础。 首先，我们对其唾液腺匀浆物活性进行了系统分析，发现姚虻唾液腺匀浆物具有 如下活性：有抗金黄色葡萄球菌活性，并且对大肠杆菌、白色念球菌和枯草杆菌都有 效；能够抑制ADP 诱导的洗涤和富血浆血小板的聚集；能够凝集兔红细胞、能够抑制 丝氨酸蛋白酶对小肽底物的水解、具有对纤维蛋白原的水解活性（金属蛋白酶）、具 有过敏原活性、能够促进肥大细胞脱粒和组氨释放；反复检测而没有发现的活性如下： 磷脂酶A2(PLA2)活性、溶血活性、血浆凝固活性、体外抗补体、血管生长促进与抑制 活性、对小鼠脾细胞因子分泌的促进和抑制活性、抗肿瘤细胞HepG2 的生长活性。 以来源姚虻唾液腺的mRNA为材料，我们成功构建了丰度为1ｘ106的姚虻唾液腺 cDNA文库。通过对400个随机克隆的测序，我们得到了编码23种保守蛋白，44种分泌 蛋白和5种功能未知的蛋白。44种分泌蛋白中比较重要的分别是：20种抗原5相关蛋白、 2种α淀粉酶、2种麦芽糖酶、2种attactins抗菌蛋白以及血管舒张肽、过氧化物酶、 抗菌肽、透明质酸酶、mucin样蛋白和脯氨酸丰富蛋白。另外，一些不知道功能的分 泌肽也被发现,这其中包括四个与Hybomitra bimaculata的分泌肽相似性达47-82%的 多肽，这些信息有助于我们发现牛虻唾液腺活性物质和加快从知道部分氨基酸序列的 蛋白的鉴定速度，加快对姚虻从宿主获得血餐的分子机制的诠释速度。 通过分子筛、高压液相色谱等程序，我们从姚虻唾液腺中得到了一个由55 个氨 基酸组成，分子量为6 kDa，含有3 对二硫键的Kunitz 型丝氨基酸蛋白酶抑制剂TYTI。 该抑制剂与Anemonia sulcata 的蛋白酶抑制剂AsKC3 和SA5II 的成熟肽部分的同源 性达66%；并且该抑制剂，对热相对稳定；对凝乳酶、弹性蛋白酶、凝血酶、胰酶等 都有抑制作用，对胰酶的抑制常数为2.586ｘ10-4M 。 通过分子筛、高压液相色谱等程序，我们从姚虻唾液腺中得到了一分子量为7 kDa，由65 个氨基酸组成且含有3 对二硫键的防御素Taymin，它与长角血蜱的防御素的相 似性达43%，但它的第二个半胱氨酸比长角血蜱的半胱氨酸靠前一个氨基酸。该抗菌 肽对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌和白色念球菌的最小抑菌浓度分别是: 160、80、140 和120μg/mL。 通过与分离丝氨酸蛋白酶抑制剂相同的生化分离手段,从姚虻唾液腺中得到一种 红细胞凝集素样活性物质TYML1，其能凝集原始和经胰酶、链霉蛋白酶和弹性蛋白酶 处理的A、B、O 和AB 血型的人、兔、绵羊、大鼠、小鼠、鹌鹑的红细胞, 对链霉蛋 白酶处理的鹌鹑红细胞的凝集效价比正常下降了8 倍；对热、酸、碱处理和蛋白酶降 解稳定；具有Ca2+依赖性，活性能为半乳糖胺和胎球蛋白所完全抑制。 通过分子筛、阴离子交换、高压液相色谱等程序，我们从姚虻唾液腺中分离得到 了一分子量为26 kDa,由234 个氨基酸组成，含有10 个半胱氨酸的血小板聚集抑制剂 Macquaritin-2,它与报道的所有血小板聚集抑制剂均不具有同源性，但是与双翅目昆 虫唾液腺过敏原却有一定的同源性(25%-33%),对其血小板聚集抑制活性研究发现:其 能抑制胰酶、花生四烯酸、Stejnulxin、TMVA、ADP、U46619 等激动剂诱导的血小板 聚集；血小板膜结合试验表明:其能与血小板细胞膜结合,故该血小板聚集抑制剂可能 通过作用血小板上的受体来阻止激动剂诱导血小板聚集。 通过分子筛、阳离子交换、高压液相色谱等程序，我们从姚虻唾液腺中分离得到 分子量为24-30 kDa 的两个血小板聚集抑制剂Macquaritin-3 和Macquaritin-1，它 们的N 端16 个氨基酸分别是V N Y C R L P C R G C D Y H V 和 V A V D Y L G L P G R G Y H V。通过PCR, Macquaritin-3 的核苷酸序列被得到，其推导蛋白的成熟区 和信号肽分别含有232 和23 个氨基酸。利用根据Macquaritin-1 的N 端氨基酸设计 的简并引物扩到含有V A V D Y L G L P 序列的两组核苷酸序列。它们与报道的所有 血小板聚集抑制剂均不具有同源性，但是其与双翅目昆虫的唾液腺抗原5 相关蛋白却 有一定的同源性。将所有血小板抑制剂及其相关序列和通过cDNA 文库筛选得到的抗 原5 相关序列进行分析,发现它们有很高的相似性,这种相似性介于33.3%-93.0%间, 且大部分高于50%。另外，两个血小板聚集抑制剂和一个可能的血小板抑制剂分别处 于这些抗原5 相关蛋白进化树的三个簇中。因此，我们推测这些过抗原5 相关蛋白可 能都具有血小板抑制剂活性。

Effect of different VOPO4 phase catalysts on oxidative dehydrogenation of cyclohexane to cyclohexene in acetic acid

alpha(1)-VOPO4, alpha(II)-VOPO4 and beta-VOPO4 have been investigated as catalysts for the gas phase oxidative dehydrogenation (ODH) of cyclohexane to cyclohexene with the addition of acetic acid (HOAc) in the feeds in a fixed bed reactor. Different VOPO4 phases showed different acidity and reducibility. beta-VOPO4 phase is more active than alpha(I)-VOPO4 and alpha(II)-VOPO4 in the ODH without acetic acid addition. In the presence of acetic acid, the acidity of the catalyst may play an important role in the ODH process. Due to higher acidity, alpha(I)-VOPO4 phase catalyst gives better catalytic performances than alpha(I)-VOPO4 and beta-VOPO4 for the ODH of cyclohexane by adding of acetic acid in the reactants.

Selective separation of yttrium by CA-100 in the presence of a complexing agent

The selective separation of Y from yttrium solution containing small heavy rare earth (HRE) impurities (Ho, Er, Tm, Yb, Lu) by liquid-liquid extraction using CA-100 in the presence of a water-soluble complexing agent of ethylenediaminetetraacetic acid (EDTA) was experimentally studied at 298K. Experiments were carried Out in two feeds, Feed-I: [RE](f) = 4.94 x 10(-3) M, Y = 98.5%, HRE (Ho, Er, Tm, Yb, Lu) = 1.5%; Feed-II: [RE](f) = 4.94 x 10(-3) M, Y = 99.9%, HRE (Ho, Er, Tm, Yb, Lu) = 0.1%, as a function of equilibrium pH (pH(eq)), the concentration ratio of [EDTA]:[HRE impurities]. It was shown that the extraction of HRE in the presence of EDTA was suppressed when compared to that of Y because of the masking effect, while the selective extraction of Y was enhanced and the separation factors increased to maximum at appropriate condition for Feed-I: Y/Ho = 1.53, Y/Er = 3.09, Y/Tm = 5.61, Y/Yb = 12.04, Y/Lu = 27.51 at pH 4.37 and [EDTA]:[HRE impurities] = 4: 1, for Feed-II: Y/Ho = 1.32, Y/Er = 1.91, Y/Tm = 2.00, Y/Yb = 3.05, Y/Lu = 3.33 at pH 4.42 and [EDTA]: [HRE impurities] = 8:1. The separation and purification of Y by this method was discussed.

The complete amino acid sequence of growth hormone and partial amino acid sequence of prolactin and somatolactin from sea perch (Lateolabrax japonicus)

Growth hormone (GH), prolactin (PRL) and somatolactin (SL) were purified simultaneously under alkaline condition (pH 9.0) from pituitary glands of sea perch (Lateolabrax japonicas) by a two-step procedure involving gel filtration on Sephadex G-100 and reverse-phase high-performance liquid chromatography (rpHPLC). At each step of purification, fractions were monitored by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and by immunoblotting with chum salmon GH. PRL and SL antisera. The yields of sea perch GH, PRL and SL were 4.2, 1.0 and 0.28 mg/g wet tissue, respectively. The molecular weights of 19,200 and 20,370 Da were estimated by SDS-PAGE for sea perch GH and PRL, respectively. Two forms of sea perch SL were found: one (28,400 Da) is probably glycosylated, while the other one (23,200 Da) is believed to be deglycosylated. GH bioactivity was examined by an in vivo assay. Intraperitoneal injection of sea perch GH at a dose of 0.01 and 0.1 mug/g body weight at 7-day intervals resulted in a significant increase in body weight and length of juvenile rainbow trout. The complete sea-perch GH amino acid sequence of 187 residues was determined by sequencing fragments cleaved by chemicals and enzymes. Alignment of sea-perch GH with those of other fish GHs revealed that sea-perch GH is most similar to advanced marine fish, such as tuna, gilthead sea bream, yellowfin porgy, red sea bream, bonito and yellow tail with 98.4, 96.2%, 95.7%, 95.2%, 94.1% and 91% sequence identity, respectively. Sea-perch GH has low identity to Atlantic cod (76.5%), hardtail (73.3%), flounder (68.4%), chum salmon (66.3%), carp (54%) and blue shark (38%). Partial amino-acid sequences of 127 of sea-perch PRL and the N-terminal of 16 amino-acid sequence of sea-perch SL have been determined. The data show that sea-perch PRL has a slightly higher sequence identity with tilapia PRL( 73.2%) than with chum salmon PRL(70%) in this 127 amino-acid sequence. (C) 2001 Elsevier Science B.V. All rights reserved.

鲨鱼软骨抗血管生成多肽的分离纯化及其生物活性

以血管生成为靶点的抗肿瘤策略是抗肿瘤领域的研究热点，目前已经发现许多天然和化学合成的抗血管生成药物。鲨鱼软骨作为抗新生血管生成因子的重要来源的研究已有20多年的历史，很多研究显示鲨鱼软骨提取物有抗血管生成活性。但鲨鱼软骨活性多肽的完整分子结构一直未见报道；鲨鱼软骨活性多肽干扰血管生成通路的信号途径尚不明确。 本文应用盐酸胍抽提、丙酮分级沉淀、超滤、凝胶层析等分离技术，从青鲨（Prionace glauca）软骨中分离纯化并鉴定了一种新的具有抗新生血管生成活性的多肽。经SDS-PAGE和N-末端氨基酸序列分析显示，该多肽分子量为15500 Da，采用蛋白数据库分析表明该多肽是一种新发现的鲨鱼软骨多肽（Polypeptide from Prionace glauca，PG155）。 体外实验显示，PG155抑制内皮细胞生长因子（vascular endothelial growth factor，VEGF）介导的人脐静脉内皮细胞（human umbilical vein endothelial cell ，HUVEC）迁移和管腔形成，并呈剂量依赖关系。200 μg/ml PG155对牛主动脉内皮细胞（Bovine Aortic Endothelial Cells，BAECs）和HUVECs及以下癌细胞，包括人肝癌细胞（human hepatoma Bel-7402 cells，Bel-7402）、 口腔上皮癌细胞（human oral epidermoid carcinoma KB cells ，KB）、人结肠癌细胞（human colon cancer HCT-18 cells，HCT-18）和人乳腺癌细胞（human breast MCF7 cancer cells ，MCF7）的增殖均无抑制作用，说明PG155无细胞毒作用。20 μg/ml PG155显著抑制HUVEC的迁移和管腔形成；40-80 μg/ml PG155 对VEGF 介导的HUVEC的迁移和管腔形成几乎完全抑制。 体内实验显示，PG155显著抑制斑马鱼胚胎模型新生血管生成，并呈剂量依赖关系。形态学观察表明PG155显著抑制斑马鱼胚胎肠下静脉（subintestinal vessels， SIVs）的生长，随着浓度的升高SIVs的生长可受到完全抑制。碱性磷酸酶染色分析显示，在一定浓度范围内，PG155随着浓度的升高对斑马鱼胚胎整体血管生成抑制作用依次增强。160 μg/ml PG155会引起斑马鱼胚胎心脏功能障碍。 由海洋生物中发现新的肿瘤新生血管生成抑制剂国内外的报道较少，我们的工作表明鲨鱼软骨可作为血管生成抑制剂的重要来源，鲨鱼软骨活性多肽PG155由于具有极低的细胞毒作用，并能抑制VEGF介导的血管生成过程，有希望成为一类新型抗肿瘤药物。

藻体对水环境中N、P及重金属Cu2+、Pb2+、Cd2+、Cr6+的吸附特征研究

随着全球生态环境的恶化，各国日益重视对水体中各种污染物的治理。利用藻类的吸收、富集和降解作用，可以去除污水中的营养物质、重金属离子和有机污染物，与其他物理、化学及工程的方法相比，该技术具有以下优点：成本低、能耗小、治理效果较好，对环境污染小，有利于资源化，有利于整体生态环境的改善，是治理水质污染的新途径。 本文利用几种大型海藻对富营养化海水进行处理，结果发现孔石莼、刚毛藻均有很强的吸收N、P的能力，吸收能力依次为褶曲刚毛藻>束生刚毛藻>孔石莼。水体中褶曲刚毛藻3 g/L含量，在3～5小时之内，可把中等以上富营养化海水中的N、P降低至一类海水水平。利用刚毛藻处理富营养化地下海水和养殖废水，进行海参和大菱鲆养殖试验，探索藻类净化水质和废水循环利用的新模式，使水体保持较低的营养盐状态，减轻养殖废水对环境的影响，实现了海水养殖业与环境的可持续发展。 刚毛藻在我国近海滩涂分布广泛，利用它来处理富营养化水体，并和水产养殖业相结合，既净化水体，使养殖废水能循环利用，满足水产养殖的需求，又改善水产业生态环境。同时，将回收藻体生产优质饲料、食品和药物等，实现藻类资源的高值利用。刚毛藻营养丰富，用其替代鼠尾藻作海参饲料，资源丰富，成本低，效果好，是一种值得加以开发利用的宝贵资源，具有广泛的应用前景。 生物吸附法是一种经济有效的移除废水中有害重金属离子的方法。由于藻类细胞壁中的多聚糖可提供吸附重金属的位点，廉价而蕴藏丰富的海藻对多种重金属表现出很强的吸附能力。所以本文通过分批实验，研究了非活体刚毛藻对水体中重金属Cu2+、Pb2+和Cd2+的吸附影响因子、吸附热力学、吸附动力学及吸附机理，得到了平衡等温线及动力学数据。吸附过程的最佳pH值为5.0，吸附量随温度的升高而增加，水体中常见的Na+、K+、Ca2+、Mg2+阳离子及Cl-、NO3-、SO42-、C2O42-等阴离子的存在对吸附的影响并不显著。EDTA存在时，吸附百分率大大降低。吸附等温线符合Langmuir和Freundlich方程。刚毛藻对重金属Cu2+、Pb2+和Cd2+的吸附容量很高，25℃时，对Cu2+、Pb2+和Cd2+的最大吸附容量分别为1.61 mmol/g、0.96 mmol/g和0.98 mmol/g，且吸附过程为吸热反应。刚毛藻对重金属Cu2+、Pb2+和Cd2+的吸附过程为化学吸附，在吸附过程中藻体表面的官能团可能与金属离子发生了螯合作用。吸附动力学过程符合pseudo-二级动力学模型，在初始的30min内，吸附速率很快，随后速率逐渐降低。解吸试验表明，用EDTA可以对重金属进行回收，刚毛藻可以循环利用。实验结果表明刚毛藻是一种高效、经济实用的生物吸附材料，可用来吸附回收水体中的重金属Cu2+、Pb2+和Cd2+等。 通过非活体刚毛藻对重金属Cr6+的吸附影响因子、吸附动力学、吸附机理的研究发现，刚毛藻对Cr6+具有很强的还原能力，对电镀废水中的Cr6+的还原去除提供了非常好的方法。吸附过程的最佳pH值为2～3，实际电镀废水通常在此pH范围，因此处理实际废水时，首先在原酸性条件下，对Cr6+进行还原去除，然后调废水pH至5.0，继续进行吸附，去除其他二价离子及被还原的三价Cr离子，实现了利用同一材料还原Cr6+为Cr3+，并将Cr3+和其他重金属离子同时去除。通过对机理的讨论，认为刚毛藻对Cr6+的生物吸附过程不是一个简单的“离子交换过程”，而是一个“吸附还原过程”。在海藻量足够的前提下，只要时间足够长，Cr6+可被彻底还原去除。 利用工业废弃物褐藻渣，对水体中重金属离子Cu2+、Pb2+、Cd2+及Cr6+的生物吸附特性分别进行了讨论，结果表明褐藻渣对重金属离子的吸附特性与刚毛藻一致，吸附等温线符合Langmuir和Freundlich方程，在25℃时，pH为5.0时，由Langmuir方程求出褐藻渣对Cu2+、Pb2+和Cd2+的最大吸附容量分别为4.20 mmol/g、3.13 mmol/g和2.97 mmol/g。褐藻渣对低、高浓度的重金属Cr6+都具有很强的吸附能力，且移除效果比较彻底。实际应用结果表明，褐藻渣是一种高效、经济实用的生物吸附材料，可用来吸附回收水体中的重金属离子，具有广泛的应用前景。

Feeding and respiration rates of a planktonic copepod (Calanus sinicus) oversummering in Yellow Sea Cold Bottom Waters

The distribution, feeding and oxygen consumption of Calanus sinicus were studied in August 2001 on a transect across Yellow Sea Cold Bottom Waters (YSCBW) and two additional transects nearby. The distribution of C. sinicus adults and copepodites stage CV appeared to be well correlated with water temperature. They tended to concentrate in the YSCBW (>10,000 ind. m(-2)) to avoid high surface temperature. Gut pigment contents varied from 0.44 to 2.53 ng chlorophyll a equivalents (chl a equiv.) ind.(-1) for adults, and from 0.24 to 2.24 ng chl a equiv. ind.(-1) for CV copepodites. We found no relationship between gut pigment contents and the ambient chl a concentrations. Although the gut evacuation rate constants are consistent with those measured for other copepods, their low gut pigment contents meant an estimated daily herbivorous ingestion of <3% of body carbon in the YSCBW and <10% outside the YSCBW. However, based on estimates of clearance rates, C. sinicus feeds actively whether in the YSCBW or not, so the low ingestion rates probably reflect shortage of food. Oxygen consumption rates of C. sinicus ranged from 0.21 to 0.84 mul O-2 ind.(-1) h(-1), with high rates often associated with high temperature. From the oxygen consumption rates, daily loss of body carbon was estimated to be 4.0-13.7%, which exceeds our estimates of their carbon ingestion rates. C. sinicus was probably not in diapause, either within or outside the YSCBW, but this cold-water layer provides C. sinicus with a refuge to live through the hot, low-food summer.

The influence of diets containing dried bivalve feces and/or powdered algae on growth and energy distribution in sea cucumber Apostichopus japonicus (Selenka) (Echinodermata : Holothuroidea)

In recent years, bivalve feces and powdered algae have been used as the food sources of holothurians in China. In this study, growth and energy budget for sea cucumber Apostichopus japonicus (Selenka) with initial wet body,veights of 32.5 1.0 g (mean +/- SE, n=45) when fed with five different granule diets containing dried bivalve feces and/or powdered algae in water temperature 13.2-19.8 degrees C and salinity 30-32ppt were quantified in order to investigate how diets influence growth and energy distribution and to find out the proper diet for land-based intensive culture of this species. Results showed that diets affected the food ingestion, feces production, food conversion efficiency and apparent digestive ratios, hence the growth and energy budget. Sea cucumbers fed with dried feces of bivalve showed poorer energy absorption, assimilation and growth than individuals fed with other four diets; this could be because feces-drying process removed much of the benefits. Dried bivalve feces alone, therefore, were not a suitable diet for sea cucumbers in intensive cultivation. The mixed diets of feces and powered algae showed promising results for cultivation of sub-adult Apostichopus japonicus, while animals fed with powdered algae alone, could not obtain the best growth. According to SGR of tested animals, a formula of 75% feces and 25% powdered algae is the best diet for culture of this species. Extruded diets were used in the present experiment to overcome shortcomings of the traditional powdered feeds, however, it seems a conflict exists between drying bivalve feces to form extruded diets and feeding sea cucumbers with fresh feces which contain beneficial bacteria. Compared with other echinoderms, in holothurians the energy deposited in growth is lower and the energy loss in feces accounts for the majority of the ingested energy. Such detailed information could be helpful in further development of more appropriate diets for culture of holothurians. (c) 2006 Elsevier B.V. All rights reserved.

Food sources of three bivalves living in two habitats of Jiaozhou Bay (Qingdao, China): Indicated by lipid biomarkers and stable isotope analysis

Food Sources of three filter-feeding bivalves from two habitats (intertidal oyster Crassostrea gigas, mussel Mytilus galloprovincialis. and subtidal cultured scallop Chlamys farreri) of Jiaozhou Bay (Qingdao,China) were determined by fatty acid and stable isotope in analysis. Cultured scallop was characterized by significant diatom markets such as 16:1/16:0 close to 1 and high ratio of 20:5(n - 3)/22:6(n - 3), hence we assume that the scallop mainly feeds on diatoms. Fatty acid biomarkers specific to bacteria and terrestrial materials were also found in considerable amounts in scallop tissue, which suggested that there were Substantial bacterial and terrestrial input into the food of the species. Intertidal oyster and mussel, however, exhibited significant flagellate marker. 22:6(n - 3). and lower level of diatom markers. which indicated that flagellates are also part of intertidal bivalves' Planktonic food Sources: meanwhile, high level of Chlorophyta fatty acid marker, Sigma 18:2(n - 6) + 18:3(n - 3), suggested that Ulva pertusa (Chlorophyta) seaweed bed supplied important food sources to intertidal bivalves. Additionally, result of stable isotope analysis showed that phytoplankton contributed 86.2 to 89.0% to intertidal bivalves' carbon budget; macroalga U. pertusa origin source had a contribution of MIX, to 11.0%, which indicated its role Lis in important supplemental food source to intertidal bivalves. From this study. it is concluded that the dietary difference of three bivalves probably relates to the different potential food sources in the scallop farm and intertidal zone in Jiaozhou Bay.

Detection of transgenic DNA in tilapias (Oreochromis niloticus, GIFT strain) fed genetically modified soybeans (Roundup Ready)

We used nested-polymerase chain reaction (PCR) to detect Roundup Ready soybean in aquatic feeds and feeding tilapias. A template concentration of 10(-10) g mu L-1 DNA solution could be detected with a dilute degree of 0.01%. Most (90.6%) of the aquatic feeds containing soybean byproduct included exogenous DNA segments. We also compared genetically modified (GM) soybean with non-GM soybean diets in feeding tilapias (Oreochromis niloticus, GIFT strain) and examined the residual fragments (254 bp) of GM soybeans. Tilapias receiving GM soybean diets had DNA fragments in different tissues and organs, indicating that exogenous GM genes were absorbed systemically and not completely degraded by the tilapia's alimentary canal.

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.