葛仙米研究进展

科技部科技型中小企业技术创新基金资助(04EFN216600329); 国家星火计划管理项目(2005EA173005)资助

饲料碳水化合物水平对南方鲇生长的影响

2002年6—8月对南方鲇(SilurusmeridionalisChen)(初始体重12.93±0.13g)进行人工配合饲料的喂养实验。实验以白鱼粉、玉米油、糊化玉米淀粉分别作为蛋白质、脂肪和碳水化合物(CBH)原料。配制等蛋白质(含量为40%),等脂肪(含量为10%),不同CBH梯度的6组饲料,饲料CBH水平分别设计为0%,6%,12%,18%,24%,30%。实验每水平设4个重复,采用室内循环水养殖系统,在27.5℃下以饱足日粮水平喂养8周。实验结果表明:随着饲料淀粉水平的增加,摄食率和生长率呈先增

黄鳝摄食活饵的初步研究

本文对不同体重的黄鳝摄食蚯蚓、蝌蚪、蛴螬的饵料系数、特定生长率、能量转化效率和最大摄食量等作了初步研究。结果表明 :在限食试验中 ,黄鳝摄食蚯蚓、蝌蚪、蛴螬的饵料系数分别为 3.2 83.89、7.0 99.0 7、3.393.4 2 ;特定生长率分别为 0 .33% 1.0 9%、1.0 9% 1.2 0 %、0 .6 5 % 0 .70 % ;能量转化效率分别为2 4 .9% 2 9.5 %、33.2 % 34.1%、2 8.8% 2 9.1%。饵料系数、特定生长率的大小主要决定于饵料性质 ,与体重(

鲤鱼sGnRH基因克隆及其在成熟个体的表达分析

采用RACE方法 ,从鲤鱼脑组织克隆了两个差异的sGnRH(salmonGnRH ,[Trp7Leu8]GnRH)cDNAs ,即cDNA1和cDNA2 ,其长度分别为 393和 4 78bp。两个cDNAs都包括一个 2 85bp开放阅读框 ,编码的sGnRH前体为 94个氨基酸残基 ,由一个信号肽、sGnRH十肽和一个由蛋白水解位点 (Gly Lys Arg)连接的促性腺激素释放激素相关肽共 3部分组成。用内含子捕获得到相应的两个差异sGnRH基因 ,即sGnRHgene1和 gene2 ,其基本结构

活体及离体条件下微囊藻毒素对鱼蛋白磷酸酶的抑制作用

用鱼组织匀浆液或纯化的酶作为酶源，研究了离体和活体条件下天然有毒物微囊藻毒素对蛋白磷酸酶的抑制作用。结果表明，３种微囊藻毒素ＬＲ、ＹＲ和ＲＲ都对蛋白磷酸酶有极强的抑制作用，毒素浓度对酶相对活力作图呈典型的Ｓ型曲线。在活体致毒时，微囊藻毒素ＬＲ可在极短时间里完全抑制鱼肝脏的蛋白磷酸酶活性。研究结果还证明，离体条件下，微囊藻毒素对鱼蛋白磷酸酶的作用模式和程度与哺乳动物中的一样，活体致毒时，微囊藻毒素对鱼蛋白磷酸酶有专一性的抑制作用。

在不同水硬度下铜对草鱼、鲢和大鳞泥鳅的急性毒性

实验以草鱼、鲢和大鳞泥鳅的鱼苗为材料,测定了水硬度对铜的急性毒性的影响,水硬度在255、141、37和14mg/L(以 CaCO_3计)时铜对草鱼的48小时 LC_(50)分别是519、354、91和76μg/L,96小时 LC_(50)则分别为460、307、67和39μg/L.在同样的硬度条件下,对鲢的48小时 LC_(50)是452、393、71和40μg/L,96小时 LC_(50)分别为452、296、41和31μg/L.大鲢泥鳅鱼苗在硬度260、137、36和10μg/L(以 CaCO_3计)

Systematic misregistration and the statistical analysis of surface data.

Spatial normalisation is a key element of statistical parametric mapping and related techniques for analysing cohort statistics on voxel arrays and surfaces. The normalisation process involves aligning each individual specimen to a template using some sort of registration algorithm. Any misregistration will result in data being mapped onto the template at the wrong location. At best, this will introduce spatial imprecision into the subsequent statistical analysis. At worst, when the misregistration varies systematically with a covariate of interest, it may lead to false statistical inference. Since misregistration generally depends on the specimen's shape, we investigate here the effect of allowing for shape as a confound in the statistical analysis, with shape represented by the dominant modes of variation observed in the cohort. In a series of experiments on synthetic surface data, we demonstrate how allowing for shape can reveal true effects that were previously masked by systematic misregistration, and also guard against misinterpreting systematic misregistration as a true effect. We introduce some heuristics for disentangling misregistration effects from true effects, and demonstrate the approach's practical utility in a case study of the cortical bone distribution in 268 human femurs.

Phylogeography of the freshwater catfish Hemibagrus guttatus (Siluriformes, Bagridae): Implications for South China biogeography and influence of sea-level changes

National Natural Science Foundation of China (NSFC) ; [2007CB411600]; [30530120]

Micronutrient niacin addition to enhance biological treatment of textile wastewater

Micronutrients play an important role in biological processes for wastewater treatment. Many industrial wastewaters lack in nutrients required for microbial growth, and this is one of the problems at many activated sludge plants treating them. In this study, the effects of the micronutrient niacin on the COD removal rates of textile wastewater, together with the effect of Mixed Liquor Suspended Solids (MLSS) on niacin, were studied. Certain improvement effects were found on the removal rates of COD, when 0.5 similar to 2.0 mg/L niacin was added to the textile wastewater. The optimal concentration of niacin was 1.0 mg/L, which was continuously added during textile wastewater treatment, and removal rates were 1.31 times compared to those of the control system. The concentration of MLSS was probably one of the factors influencing treatment efficiency, and the biological performance of treatment system could be optimized through micronutrient niacin supplements.

Molecular characterisation and inductive expression of a fish protein arginine methyltransferase 1 gene in response to virus infection

Protein arginine methyltransferase 1 (PRMT1) is currently thought as an effector to regulate interferon (IFN) signalling. Here Paralichthys olivaceus PRMT1 (PoPRMT1) gene was identified as a vitally induced gene from UV-inactivated Scophthalmus maximus Rhabdovirus (SMRV)-infected flounder embryonic cells (FEC). PoPMRT1 encodes a 341-amino-acid protein that shares the conserved domains including post-I, motif I, II and III. Homology comparisons show that the putative PoPMRT1 protein is the closest to zebrafish PMRT1 and belongs to type I PRMT family (including PRMT1, PRMT2, PRMT3, PRMT4, PRMT6, PRMT8). Expression analyses revealed an extensive distribution of PoPMRT1 in all tested tissues of flounder. In vitro induction of PoPRMT1 was determined in UV-inactivated SMRV-infected FEC cells, and under the same conditions, flounder Mx wash also transcriptionally up-regulated, indicating that an IFN response might be triggered. Additionally, live SMRV infection of flounders induced an increased expression of PoPRMT1 mRNA and protein significantly in spleen, and to a lesser extent in head kidney and intestine. Immunofluorescence analysis revealed a major cyptoplasmic distribution of PoPRMT1 in normal FEC but an obvious increase occurred in nucleus in response to UV-inactivated SMRV. This is the first report on in vitro and in vivo expression of fish PRMT1 by virus infection, suggesting that PoPRMT1 might be implicated in flounder antiviral immune response. (c) 2006 Elsevier Ltd. All rights reserved.

Isolation and characterization of polymorphic microsatellites in a Yangtze River fish, brass gudgeon (Coreius heterodon Bleeker)

The brass gudgeon (Coreius heterodon) is a fish of economic importance in the Yangtze River. From a (GATA)(n)-enriched genomic library, 25 microsatellites were developed by employing the fast isolation by AFLP of sequences containing repeats (FIASCO) protocol. Nine loci exhibited polymorphism with two to 12 alleles (mean 3.9 alleles/locus) in a test population, and observed heterozygosity ranged from 0.1111 to 0.9630 (mean 0.4426). Three of the nine loci showed polymorphism in a congeneric species, the largemouth bronze gudgeon Coreius guichenoti. These loci should provide sufficient level of genetic diversity to evaluate the fine-scale population structure of C. heterodon.

Partial compensatory growth in hybrid tilapia Oreochromis mossambicus x O-niloticus following food deprivation

The capacity of hybrid tilapia Oreochromis mossambicus x O. niloticus [23.2 +/- 0.2 g (mean +/- SE)] to show compensatory growth was assessed in an 8-week experiment. Fish were deprived of feed for 1, 2 and 4 weeks, and then fed to satiation for 4 weeks; fish fed to satiation during the experiment served as control. Water temperature gradually declined from 28.1 to 25.5 degrees C throughout the experiment. Specific growth rate (SGR) decreased with progressive food deprivation. At the end of deprivation, body weight was lower in the deprived fish than in the control. Fish deprived for 4 weeks exhibited lower contents of lipids and energy in whole body, and higher moisture content and ratio of protein to energy (P/E) than those of the control; they also consumed feed faster than the control when normal feeding was resumed. All deprived fish showed higher food intake (FI) than that of the control during re-alimentation; however, enhanced SGR was only observed in the fish deprived for 4 weeks. There were no significant differences in digestibility of protein and energy, food efficiency (FE) or energy retention efficiency between the control and deprived fish. At the end of re-alimentation, deprived fish failed to catch up in body weight with the control, while content of moisture, lipids and energy, and P/E in whole body of the deprived fish did not significantly differ from that of the control. The results of the experiment revealed that the hybrid tilapia reared in freshwater showed partial capacity for compensatory growth following food deprivation of 4 weeks, and that growth compensation was due mainly to increased FI, rather than to improved FE.

Effects of microcystins on the growth and the activity of superoxide dismutase and peroxidase of rape (Brassica napus L.) and rice (Oryza sativa L.)

Microcystins are naturally occurring hepatotoxic cyclic heptapeptides produced by some toxic freshwater cyanobacterial species. In this study, crude extract of toxic cyanobacterial blooms from Dianchi Lake in southwestern China was used to determine the effects of microcystins on rape (Brassica napus L.) and rice (Oryza sativa L.). Experiments were carried out on a range of doses of the extract (equivalent to 0, 0.024, 0.12, 0.6 and 3 mug MC-LR/ml). Investigations showed that exposure to microcystins inhibited the growth and development of both rice and rape seedlings, however, microcystins had more powerful inhibition effect on rape than rice in germination percentage of seeds and seedling height. Microcystins significantly inhibited the elongation of primary roots of rape and rice seedlings. Determination of the activities of peroxidase and superoxide dismutase demonstrated that microcystin stress was manifested as an oxidative stress. Using ELISA, microcystins were examined from the extract of exposed rape and rice seedlings, indicating that consumption of edible plants exposed to microcystins via irrigation route may have health risks. Significantly different levels of recovered microcystins between exposed rice and rape seedlings Suggested that there might be different tolerant mechanisms toward microcystins. (C) 2004 Elsevier Ltd. All rights reserved.

Structural and optical properties of quaternary AlInGaN epilayers grown by MOCVD with various TMGa flows

AlInGaN quaternary epilayers have been grown with various TMGa flows by metalorganic chemical vapor deposition to investigate the influence of growth rate on the structural and optical properties. Triple-axis X-ray diffraction measurements show AlInGaN epilayers have good crystalline quality. Photolummescence (PL) measurements show that the emission intensity of AlInGaN epilayers is twenty times stronger than that of AlGaN epilayer with comparable Al content. V-shaped pits are observed at the surface of AlInGaN epilayers by atomic force microscopy (AFM) and transmission electron microscopy (TEM). High growth rate leads to increased density and size of V-shaped pits, but crystalline quality is not degraded. (C) 2003 Elsevier B.V. All rights reserved.