单苯环氯取代指数法预测二噁类化合物PCDDs的正辛醇/水分配系数

采用单苯环氯取代指数作为氯代二苯并二口恶口英类化合物 (PCDDs)的分子结构描述符 ,通过正向逐步线性回归方法建立了PCDDs的logKow与分子结构描述符之间的定量关系模型。与文献报道的MOD模型相比 ,该模型不仅具有显著的相关性 (n =43,Radj=0 898,SE =0 195 ,在α =0 0 5时 ,F =2 0 45 5 ,p =0 0 0 0 0 ) ,而且对于分子结构具有更好的区分能力。利用建立的模型 ,对没有logKow文献值的其他 33种PCDDs化合物给出了预测值

原位杂交和原位PCR技术在鱼类基因定位中的应用

国家自然科学基金（项目编号：39730290）

在患病鳜鱼组织中观察到3种病毒

在患暴发性流行病的鳜鱼组织中观察到 3种不同形态的病毒 ,它们分别是直径约为2 80nm的球形病毒、大小约为 2 5 0nm× 1 2 0nm的弹状病毒和大小约为 2 0 0nm× 1 0 0nm的杆状病毒 .这种现象表明 ,单一病毒疫苗难以达到预防鳜鱼暴发性流行病的原因可能是由于鳜鱼受到多种病毒病原的侵染 ,提示鳜鱼病毒病的防治不要忽视病毒病原的复杂性 .

光照、温度及宿主粘液对河鲈锚首吸虫虫卵孵化的影响

光照、温度及宿主粘液对河鲈锚首吸虫虫卵孵化的影响夏晓勤，聂品，姚卫建（中国科学院水生生物研究所，武汉４３００７２）关键词河鲈锚首吸虫，虫卵孵化，鳜鱼ＥＦＦＥＣＴＳＯＦＬＩＧＨＴ，ＴＥＭＰＥＲＡＴＵＲＥＡＮＤＨＯＳＴＭＵＣＵＳＯＮＴＨＥＥＧＧＨＡＴＣＨ...

鲤痘疮病病原的电镜观察初报

<正> 痘疮病是鲤越冬前后常见的疾病。过去由于该病在池塘中流行不广,危害也不大,因而未引起足够的重视。近年来由于网箱养鱼等高密度养殖技术的推广,该病日益常见而且严重。本文报道了患痘疮病鲤鱼组织的电镜观察。

茭草叶饲养草鱼效果

<正> 茭草又称野菰(Zizania latifolia),广泛分布于我国内陆水体,在湖北省洪湖中,茭草是沿岸呈环带状分布的优势挺水植物。由于该湖年平均水深仅1.35米,底泥肥沃,适于茭草生长繁殖,群落面积已达22.7万亩,占该湖总面积的42％。每年生产茎叶干物质达15万吨以上,但绝大部分废弃分解还湖,未被充分利用。根据洪湖大水面水体生物生产力综合开发利用研究计划,我们对茭草不同器官化学成分分析的结果证明,茭草乃优质饲料,茭草叶含粗蛋白16.8—18.7％,其必需氨基酸组成比例与草鱼肌

引起橡胶和马尾松木材蓝变的真菌—可可球二孢

<正> 可可球二泡(Botryodiplodia theobromae Pat.)早在1879年就被Cooke发现,目前,至少拥有48个异名,常见的异名是Diplodia theobromae(Pat.)Nowell,Diplodia natalensis PoleEvans,Lasiodiplodia theobromae(Pat.)Griff.＆ Maubl。Punithalingam和Sutton分别对该菌作过详细的评述。它广泛分布于热带、亚热带和温带。其寄主植物已知约500种,它不但引起植物病害,

怀念伍献文所长

<正> 1985年4月3日,我们敬爱的老所长、我国鱼类学和水生生物学的奠基人之一、著名的动物学家伍献文教授安详地离开了人世。伍献文教授的一生是为发展中华民族文化科学事业而奋斗的一生,他的历史业绩将永远为人们所缅怀。

中国胭脂鱼的骨骼形态和胭脂鱼科的分类位置

<正> 中国胭脂鱼Myxocyprinus asiaticus(Bleeker)是迄今知道胭脂鱼科(Catostomidae)分布于我国的一个种,而该科的大多数种属分布于北美洲,总计有14个现存属,大约80个种(Miller,1958)。 方炳文(Fang,1934)对中国胭脂鱼除了发表一个头骨及下咽齿的照片外,主要是阐明这种鱼的体形随不同体长(实际是不同龄期)而改变的事实。Nelson(1948)作了胭脂鱼韦氏器的比较解剖,他提到中国胭脂鱼第二和第三脊椎具有分离的椎体和第一脊椎存在一对横突之外,只简单地

Oxidative stress response after prolonged exposure of domestic rabbit to a lower dosage of extracted microcystins

Oxidative stress response after prolonged exposure to a low dose of microcystins (MCs) was studied in liver, kidney and brain of domestic rabbits. Rabbits were treated with extracted MCs (mainly MC-LR and MC-RR) at a dose of 2 MC-LReq. mu g/kg body weight or saline solution every 24 h for 7 or 14 days. During the exposure of MCs, increase of lipid peroxidation (LPO) levels were detected in all the organs studied, while antioxidant enzymes responded differently among different organs. The enzyme activities Of Superoxide dismutase (SOD). catalase (CAT) and glutathione reductase (GR) in liver decreased in the MCs treated animals. In brain, there were obvious changes in glutathione peroxidase (GPx) and GR, while only CAT was obviously influenced in kidney. Therefore, daily exposure at a lower dosage of MCs, which mimicked a natural route of MCs. could also induce obvious oxidative stress in diverse organs of domestic rabbits. The oxidative stress induced by MCs in brain was as serious as in liver and kidney, suggesting that brain may also be a target of MCs in mammals. And it seems that animals may have more time to metabolize the toxins or to form an adaptive response to reduce the adverse effects when exposed to the low dose of MCs. (C) 2008 Elsevier B.V. All rights reserved.

Rana grylio virus thymidine kinase gene: an early gene of iridovirus encoding for a cytoplasmic protein

The presence of thymidine kinase (TK) is a feature of many large DNA viruses. Here, a TK gene homologue was cloned and characterized from Rana grylio virus (RGV), a member of family Iridoviridae. RGV TK encodes a protein of 195 aa with a predicted molecular mass of 22.1 kDa. Homologues of the protein were present in all the currently sequenced iridoviruses, and phylogenetic analysis showed that it was much close to cellular TK type 2 (TK2), deoxycytidine kinase (dCK) and deoxyguanosine kinase (dGK). Subsequently, Western blotting revealed TK expression increased with time from 6 h post-infection in RGV-infected cells. Using drug inhibition analysis by protein synthesis inhibitor (cycloheximide) and DNA replication inhibitor (cytosine arabinofuranoside), RGV TK was classified as the early expression gene during in vitro infection. Subcellular localization by TK-GFP fusion protein expression and immunofluorescence staining showed RGV TK was an exclusively cytoplasmic protein in fish cells. Collectively, current data indicate that RGV TK was an early gene of iridovirus which encoded a cytoplasmic protein in fish cells.

Toll-like receptor 3 regulates Mx expression in rare minnow Gobiocypris rarus after viral infection

Toll-like receptor 3 (TLR3) plays a key role in activating immune responses during viral infection. To study the genes involved in the regulatory function of TLR3 in the rare minnow Gobiocypris rarus after viral infection, a full-length cDNA of TLR3 (GrTLR3) with a splice variant (GrTLR3s) was identified by homologous cloning and RACE techniques. The antiviral effector molecule Mx gene was cloned and partially sequenced. The mRNA expression levels of GrTLR3, GrTLR3s, and Mx were studied in different tissues before and after virus infection by real-time quantitative RT-PCR. The transcripts of all three genes in liver were significantly increased following GCRV infection (P<0.05). The mRNA levels in liver were upregulated at 24 h post-injection for GrTLR3 and GrTLR3s, and at 12 h for Mx. The upregulated expression levels were several folds for GrTLR3s, tens of folds for GrTLR3, and hundreds of folds for Mx. By semi-quantitative RT-PCR, GrTLR3 and Mx expressed at all the developmental stages, whereas GrTLR3s could only be detected at later developmental stages. Using RNAi and transgenic techniques, GrTLR3 mediated Mx expression but GrTLR3s did not. The time-dependent upregulation of receptor and effector, and the Mx over-expression dependent on TLR3, indicated that GrTLR3 regulated Mx expression in viral infection through a configuration change in rare minnow, and its splice variant did not contribute to the process.

Seasonal pattern of reproduction of Hizikia fusiformis (Sargassaceae, Phaeophyta) from Nanao Island, Shantou, China

The maturation pattern of sexual reproduction in Hizikia fusiformis (Harvey) Okamura (Sargassaceae, Phaeaophyta) was examined in 2003 at Yunao Bay, Nanao Island, Shantou, China. Maturation began in mid-April (seawater temperature 19-21 degrees C), reached the peak in mid-May (maturation rate ca. 70%, and seawater temperature 23.5-25 degrees C) and finished in late-June (seawater temperature 27.5-30 degrees C). The Hizikia plants continued to gain the length from the beginning of maturation season to reach a maximum mean length of 34.8 cm in mid-May, after which the mean length was reduced drastically due to the senescence and rupture of the larger plants in size. The major portion of the mature plants belonged to the larger plants between April and May, but to the smaller ones in June. It is suggested that the plant must achieve a critical size before reproductive maturation occurred. There was a positive relationship between the number of receptacles (NR), as well as the reproductive allocation (RA), and the plant size of Hizikia population, with the recorded maximum values of NR and RA being 1220 and 64.3% respectively, for a single plant.