防洪整治工程对白鱀豚和江豚的影响分析

自 1998年大洪水后 ,为了保障人民生命财产的安全 ,水利部门正在规划一系列长江中下游防洪整治工程。根据工程规划方案 ,结合白豚和江豚种群目前的现状 ,综合分析了部分规划中的防洪工程对白豚和江豚的影响。主要包括两个方面 ,一是施工期间的影响 ,二是工程结束后对环境的改变而带来的影响。经分析认为 ,有些工程 ,如洲湾裁弯取直工程、鄱阳湖建闸控制工程将对白豚和江豚产生巨大不利影响 ,建议在近期内不考虑实施。另一些工程如在施工期间和完工后采取积极、有效的保护措施 ,从白豚和江豚保护的角度分析是可行的

原位杂交研究对虾白斑杆状病毒在虾体内感染过程

应用地高辛标记的对虾白斑杆状病毒 (whitespotsyndromebaculovirus,WSSV)核酸探针 ,与人工感染后不同时间采集的对虾组织样品进行原位杂交 ,以动态研究病毒从侵染至对虾发病死亡的过程。将典型感染WSSV的病虾组织投喂健康对虾 ,结果显示 :WSSV首先通过侵染消化道上皮进入虾体内增殖 ,此后随着细胞裂解、病毒粒子释放 ,游离的病毒粒子伴随血淋巴循环进而侵染其它靶组织 ,直至对虾发病死亡。

人工湿地系统去除藻毒素研究

以含水华的鱼塘水作为进水灌溉两套上行流 -下行流人工湿地系统 ,系统内种植芦苇等水生植物。灌溉一周后收集人工湿地进出水水样 ,用HPLC法检测其藻毒素含量 ,结合温度、电位、溶氧等理化指标和细菌、藻类数量的变化 ,分析人工湿地系统对藻毒素的去除效果及影响其效果的可能因素。结果表明 ,人工湿地系统对藻毒素有一定的去除作用 ,对藻毒素含量 0 .117g/L的进水 ,两套系统去除率分别为 6 8.5%和 34.6 % ,芦苇 -水葱组合的湿地系统去除效果优于茭白 -石菖蒲组合的湿地系统。在三种主要藻毒素RR、

鱼类精子携带的外源基因导入

将鲤鱼（或泥鳅）精子在保存液内与人生长激素（ｈＧＨ）重组质粒ＤＮＡ保温，再与鲤（或泥鳅）卵受精。由此发育的鱼苗经ＤＮＡ分子杂交和ＰＣＲ检测证明，３３．３％（或３７．０％）的个体带ｈＧＨ基因，其拷贝数在４—１５０／细胞之间。在一定条件下，精子可作为携带外源基因的载体，通过受精作用产生转基因鱼。

叶绿体陪伴蛋白在几种藻类中的存在和分布

用豌豆叶绿体陪伴蛋白（ｃｈ－ｃｐｎ６０）的杭体对衣藻和多种蓝藻细胞提取液作Ｗｅｓｔ－ｅｒｎｂｌｏｔ分析表明：真核的衣藻和原核的有异形胞丝状蓝藻的一种鱼腥藻中存在一种与豌豆ｃｈ－ｃｐｎ６０抗体有交叉反应的蛋白，其一个亚基的分子量与豌豆该蛋白的分子量相似，而另一亚基的分子量高于豌豆的β亚基分子量。绿藻和丝状蓝藻中这一蛋白在热处理后含量增加，而经－２０℃冷处理１２ｈ后含量明显下降。在单细胞蓝藻中则检测不到这种蛋白。

东湖异养细菌群落的分类结构和聚类分析

对东湖异养细菌群落结构采用系统分类和微机聚类分析方法作了比较研究。169株由东湖Ⅰ、Ⅱ、Ⅲ站水体中分离的异养细菌分别隶属于30个细菌属。其中以芽孢杆菌属居于明显优势,其次是微球菌属。在不同水域或水层,细菌的分布表现有一定的差别,但各站间多样性指数值没有明显的差异。基于113项生物学特性检测结果,采用lBM PC/XT微机聚类分析后计算各站细菌的多样性指数发现:Ⅰ站明显高于Ⅱ、Ⅲ两站,43项检测系统所得结果与此表现了一致的趋势。这与东湖各站水环境的理化分析参数是比较吻合的。作者对以上结果作了讨论。

中国淡水轮虫新资料

<正> 1978年7月下旬至9月中旬,作者到华南地区13个水库进行湖沼学调查,共采集了浮游动物定性样品27个,定量样品38个。经初步鉴定,发现轮虫种类非常丰富,共有57种,其中包括新种1个,新亚种3个,新纪录3个。现描述于下。模式标本均存中国科学院水生生物研究所。

Effects of thiamine on treatment performance of textile wastewater

Textile wastewater is commonly treated with activated sludge process technology. However, its treatment performance has not been demonstrated to be very effective. In this study, the effects of micronutrient thiamine on removal efficiencies of dissolved organic carbon (DOC) and chemical oxygen demand (COD) of textile wastewater in a batch test, together with its effect on the oxygen uptake rate (OUR) of activated sludge, were evaluated. Significant improvements were observed in the removal rates of DOC, COD and OUR with 121%, 156% and 121% of those of the control, respectively, when 0.5-2.0 mg/L thiamine was added to the wastewater treatment system. Thiamine could be probably used to improve the treatment performance of textile wastewater.

Studies on the toxic effects of La3+ to Tetrahymena thermophila by microcalorimetry

The toxic effects of La3+ on Tetrahymena thermophila have been studied by microcalorimetry at 28 degrees C. The metabolic rate constant (r) and peak time were linked to the concentration of La3+. The changes of metabolic rate constant indicated that low-concentration La3+ (0-75 mg/L) had no significant effects on the metabolism of Tetrahymena cells but high-concentration La3+ (100-175 mg/L) could inhibit their metabolism. From the results obtained by cell counting and fluorescence depolarization measurements, the inhibition of metabolism resulted from the decrease in cell number and the reduction in cell membrane fluidity. According to the results, it is clear that the metabolic mechanism of Tetrahymena cells has been changed with the addition of high-concentration La3+. In addition, microcalorimetry of Tetrahymena could be a sensible, easy-to-use, and convenient method for monitoring the potential effects of rare earth elements on cells and the freshwater ecosystem.

Crustacean zooplankton distribution patterns and their biomass as related to trophic indicators of 29 shallow subtropical lakes

A comparative limnological study was carried out to present a snapshot of crustacean zooplankton communities and their relations to environmental factors to test whether there is a consistent relationship between crustacean biomass and trophic indicators among lake groups with similar trophic conditions. The study lakes showed a wide range of trophic status, with total phosphorus (TP) ranging from 0.008 to 1.448mgL(-1), and chlorophyll a from 0.7 to 146.1 mu g L-1, respectively. About 38 species of Crustacea were found, of which Cladocera were represented by 25 taxa (20 genera), and Copepoda by 13 taxa (I I genera). The most common and dominant species were Bosmina coregoni, Moina micrura, Diaphanosoma brachyurum, Cyclops vicinus, Thermocyclops taihokuensis, Mesocyclops notius and Sinocalanus dorrii. Daphnia was rare in abundance. Canonical correspondence analysis showed that except for four species (D. hyalina, S. dorrii, C. vicinus and M. micrura), almost all the dominant species had the same preference for environmental factors. Temperature, predatory cyclopoids and planktivorous fishes seem to be the key factors determining species distribution. TP was a relatively better trophic indicator than chlorophyll a to predict crustacean biomass. Within the three groups of lakes, however, there was no consistent relationship between crustacean biomass and trophic indicators. The possible reason might be that top-down and bottom-up control on crustaceans vary with lake trophic state. The lack of significant negative correlation between crustacean biomass and chlorophyll a suggests that there was little control of phytoplankton biomass by macrozooplankton in these shallow subtropical lakes. (c) 2007 Elsevier GmbH. All rights reserved.

Metals in surface sediments of large shallow eutrophic lake chaohu, china

Metal contents of surface sediments were analyzed temporally and spatially in Lake Chaohu, China. No obvious temporal variations were observed, which probably due to physio- and bio- mixing, e.g. wind and microbes, in this lake. Enrichment factor of some metals were generally greater than 1.0, suggesting significant anthropogenic impact on metal levels. Significantly positive correlations between concentrations of nutrient and metals indicated that the nutrients transported to this lake contributed, to some extent, to the enrichment of metals. The correlation between trace metals concentrations indicated the co-contamination of anthropogenically derived metal enrichment in surface sediment of Lake Chaohu.

Sedimentary records of water environment in lake Chaohu in the Yangtze delta region, China

Three lacustrine core samples were collected from Chaohu lake in December 2002 in the Yangtze delta region. The grain sizes were analyzed using a Laser Analyzer to obtain grain-size parameters. Sediment geochronology was determined in radioisotopes Cs-137 and the average sedimentary rates are 0.29cm.a(-1), 0.35 cm.a(-1) and 0.24cm-a(-1) in Cores C 1, C2 and C3, respectively. The grain-size parameters of the deposits vary regularly with the fluctuation of hydrodynamics. From 1950s to the beginning of 20th century, coarse-grained sediment was deposited, suggesting strong hydraulic conditions and high water-level periods with much precipitation; from the start of 20(th) century to latter half of 18(th) century, fine-grained sediment was deposited, indicating that weak hydraulic conditions and low water-level periods with less precipitation; before the first half of 18(th) century, coarse-grained sediment was deposited, suggesting great velocity of flow and high water-level periods of more precipitation.

Enhanced resistance to Aeromonas hydrophila infection and enhanced phagocytic activities in human lactoferrin-transgenic grass carp (Ctenopharyngodon idellus)

Human lactoferrin (hLF) is an iron-binding protein with antimicrobial and immunomodulatory activities. hLF cDNA was transferred into grass carp via electroporated sperm. The production of transgenic fish was as high as 55% tinder the best parameters. 2(11) pulses and 20-min incubation. The expression of the transgene was demonstrated by the detection of hLF mRNA by RT-PCR. We also investigated the response of G(0) transgenic grass carp to Aeromonas hydrophila infection. Serum lysozyme activities (P>0.05) and phagocytic activities of kidney cells (P<0.05) were measured in transgenic individuals. The transgenic fish not only cleared A. hydrophila significantly faster than the control carp (P<0.05), but also showed enhanced phagocytic activities. The result shows that hLF has immunomodulatory activities in hLF-transgenic grass carp. The transgenic grass carp exhibited enhanced immunity to A. hydrophila infection. These results reveal that the mechanisms of disease resistance are different between hLF-transgenic plants and hLF-transgenic grass carp. (C) 2004 Elsevier B.V. All rights reserved.

SESTON IN A SEASONALLY FLOODED LAKE OF THE CENTRAL CHANGJIANG RIVER (CHINA)

Seston was studied during inundation in a seasonally flooded lake of Changjiang River system (Lake Chenhu, Hanyang, P.R. China). Particulate organic matter (POM), particulate inorganic matter (PIM), particulate organic carbon (POC) and particulate organic nitrogen (PON) concentrations were highest upon initial inflow of river water, as a result of the riverine transport of allochthonous seston into the lake, and during the initial draining phase, coinciding with the postflood development of phytoplankton biomass and accumulation of detritus from the decomposition of the inundated vegetation grown during the preceding period of exposure. However seston concentrations were lowest shortly after the termination of flood inflow, presumably due to sedimentation and river water dilution. Seston food quality, based on POM : PIM, C : N and Algal-AFDW : POM ratios, was higher during the early high water phase than during the filling and draining phases.

The growth temperatures dependence of optical and electrical properties of InN films

InN films grown on sapphire at different substrate temperatures from 550 degrees C to 700 degrees C by metalorganic chemical vapor deposition were investigated. The low-temperature GaN nucleation layer with high-temperature annealing (1100 degrees C) was used as a buffer for main InN layer growth. X-ray diffraction and Raman scattering measurements reveal that the quality of InN films can be improved by increasing the growth temperature to 600 degrees C. Further high substrate temperatures may promote the thermal decomposition of InN films and result in poor crystallinity and surface morphology. The photoluminescence and Hall measurements were employed to characterize the optical and electrical properties of InN films, which also indicates strong growth temperature dependence. The InN films grown at temperature of 600 degrees C show not only a high mobility with low carrier concentration, but also a strong infrared emission band located around 0.7 eV. For a 600 nm thick InN film grown at 600 degrees C, the Hall mobility achieves up to 938 cm(2)/Vs with electron concentration of 3.9 x 10(18) cm(-3).