香溪河水系大型底栖动物的群落结构及生态位

2005年7月～2006年6月对三峡水库湖北库区最大支流香溪河的大型底栖动物进行定量采集,并对所得数据进行了数理统计分析及生态位分析.结果表明,香溪河水系大型底栖动物物种丰富度在不同季节、不同支流间差异均显著;密度在各季节间差异显著.四节蜉、高翔蜉、锯形蜉、朝大蚊和扁蜉生态位较宽;Tetropina sp.、短尾石蝇、黑蝇生态位较窄.四节蜉、高翔蜉、锯形蜉、朝大蚊与其它分类单元生态位重叠值较大,黑蝇、短尾石蝇、直突摇蚊、Tetropinasp.与其它分类单元生态位重叠值较小.相对丰度和生态位宽度对生态位重

膜生物反应器活性污泥酶活与磷脂脂肪酸分析

分析了不同污染负荷下膜生物反应器的运行效率,并运用酶活表征污泥活性,用磷脂脂肪酸(PLFAs)分析微生物种群结构及其分布特征.结果表明,膜生物反应器对COD,TP,TN,NH4+-N保持着高而稳定的去除率,不同有机负荷下去除率差异不大(P>0.05);磷酸酶活性在低污染负荷下最高,脱氢酶、β-糖苷酶在中低污染负荷时的活性比高污染负荷时高,脲酶及蛋白酶活性随负荷增加而升高;活性污泥PLFAs组成以单不饱和脂肪酸、饱和脂肪酸和支链脂肪酸为主,而多不饱和脂肪酸与环丙烷脂肪酸含量较少,特征脂肪酸的比值表明在反应器

三峡库区四条支流藻类多样性评价及“水华”防治

应用多样性指数、丰富度指数和均匀性指数对长江4条支流水域的藻类多样性进行了评价.比较了4条支流春、秋两季浮游藻类优势种、细胞密度和生物量等指标,对三峡蓄水后库区“水华”成因进行了初步分析.结果表明,4条支流的营养水平均属于中-富营养型,童庄河的水质最差,其次为香溪河和青干河,九畹溪的水质较好.春季硅藻的种类数多,绿藻种类数少;秋季则相反.藻类细胞密度的最高值出现在香溪河(6.036×106个/L),生物量的最高值出现在童庄河(19.997mg/L).2项指标的最低值均出现在九畹溪.在春季,童庄河还出现了拟

固相萃取高效液相色谱法测定水中痕量微囊藻毒素

微囊藻毒素是有害的蓝藻水华释放的有毒代谢物 ,对人类及环境具有很大危害性。建立了固相萃取 高效液相色谱测定水中痕量藻毒素的方法。该法对两种常见微囊藻毒素MC LR、MC RR的检测限为 0 .0 2～ 0 .0 5 μg/L ,线性定量范围为 0 .1～ 5 0 μg/L。应用该法分析了天然水样 ,表明方法具有实用性

用污染指示菌评价城市水体污染的研究

选择湖南省常德市江北城区水体为代表开展本项研究。结果表明，水体中污染指示菌，总大肠菌群（ＴＣ）和粪大肠菌群（ＦＣ）密度同ＢＯＤ＿５负荷以及综合污染指数Ｐ呈高度正相关。所以，污染指示菌指标，特别是粪大肠菌群指标足综合评价城市污水，尤其是生活污水污染的一个必不可少的重要参数。对该城区水体细菌污染的评价结果是，生活污水排放愈集中的地区，细菌污染愈严重。其中护城河水的ＴＣ密度超出我国地面水Ⅲ级标准４个数量级；ＦＣ密度超过ＷＨＯ娱乐用水标准３个数量级。护城河是细菌污染最严重水体。包括滨湖公园内湖在内的接纳生活污水多

不同碳源对球孢鱼腥藻生长的影响

本文研究了有机碳源和无机碳源对球胞鱼腥藻生长的影响,结果表明:有机碳源中葡萄糖以0.5—1.0μg/mL、蔗糖以5.0μg/mL促进其生长效果最好;无机碳源中,碳酸钠以10.0—15.0μg/mL、碳酸氢钠以10.0μg/mL效果最好。葡萄糖和蔗糖的浓度高低对球孢鱼腥藻叶绿素a的含量没有明显影响,但前者略高于后者。碳酸钠和碳酸氢钠的浓度在5.0μg/mL时均提高了叶绿素a含量。四种碳源都提高了球孢鱼腥藻的同氮活性,有机碳源中蔗糖优于葡萄塘,无机碳源中碳酸钠优于碳酸氢钠。

Comparative responses in rare minnow exposed to 17 beta-estradiol during different life stages

Present in the excrement of humans and animals, 17 beta-estradiol (E-2) has been detected in the aquatic environment in a range from several nanograms to several hundred nanograms per liter. In this study, the sensitivities of rare minnows during different life stages to E-2 at environmentally relevant (5, 25, and 100 ng l(-1)) and high (1000 ng l(-1)) concentrations were compared using vitellogenin (VTG) and gonad development as biomarkers under semistatic conditions. After 21 days of exposure, VTG concentrations in whole-body homogenates were analyzed; the results indicated that the lowest observed effective concentration for VTG induction was 25 ng l(-1) E-2 in the adult stage, but 100 ng l(-1) E-2 in the larval and juvenile stages. After exposure in the early life stage, the larval and juvenile fish were transferred to clean water until gonad maturation. No significant difference in VTG induction was found between the exposure and control groups in the adults. However, a markedly increased proportion of females and appearance of hermaphrodism were observed in the juvenile-stage group exposed to 25 ng l(-1) E-2. These results showed that VTG induction in the adult stage is more sensitive than in larval and juvenile stages following exposure to E-2. The juvenile stage may be the critical period of gonad development. Sex ratio could be a sensitive biomarker indicating exposure to xenoestrogens in early-life-stage subchronic exposure tests. The results of this study provide useful information for selecting sensitive biomarkers properly in aquatic toxicology testing.

DE-71-induced apoptosis involving intracellular calcium and the Bax-mitochondria-caspase protease pathway in human neuroblastoma cells In vitro

Polybrominated diphenyl ethers (PBDEs) are used extensively as flame-retardants and are ubiquitous in the environment and in wildlife and human tissue. Recent studies have shown that PBDEs induce neurotoxic effects in vivo and apoptosis in vitro. However, the signaling mechanisms responsible for these events are still unclear. In this study, we investigated the action of a commercial mixture of PBDEs (pentabrominated diphenyl ether, DE-71) on a human neuroblastoma cell line, SK-N-SH. A cell viability test showed a dose-dependent increase in lactate dehydrogenase leakage and 3-(4,5-dimethylthia-zol-2-yl)-2,5-diphenyl-tetrazolium bromide reduction. Cell apoptosis was observed through morphological examination, and DNA degradation in the cell cycle and cell apoptosis were demonstrated using flow cytometry and DNA laddering. The formation of reactive oxygen species was not observed, but DE-71 was found to significantly induce caspase-3, -8, and -9 activity, which suggests that apoptosis is not induced by oxidative stress but via a caspase-dependent pathway. We further investigated the intracellular calcium ([Ca2+](i)) levels using flow cytometry and observed an increase in the intracellular Ca2+ concentration with a time-dependent trend. We also found that the N-methyl d-aspartate (NMDA) receptor antagonist MK801 (3 mu M) significantly reduced DE-71-induced cell apoptosis. The results of a Western blotting test demonstrated that DE-71 treatment increases the level of Bax translocation to the mitochondria in a dose-dependent fashion and stimulates the release of cytochrome c (Cyt c) from the mitochondria into the cytoplasm. Overall, our results indicate that DE-71 induces the apoptosis of ([Ca2+](i)) in SK-N-SH cells via Bax insertion, Cyt c release in the mitochondria, and the caspase activation pathway.

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.