Cultured gill epithelial cells from tilapia (Oreochromis niloticus): a new in vitro assay for toxicants

A culture gill epithelium from seawater-adapted tilapia (Oreochromis niloticus) was developed for testing PAHs and dioxin-like contaminants in seawater. The epithelia consists two to three layers of epithelial cells incorporating both pavement cells and mitochondria-rich cells (MRCs). Polarity and a stable transepithelial resistance (TER) were maintained. and closely resembled those in fish gills in vivo. The tightness (integrity) of the epithelia remained unchanged upon exposure to benzo[a]pyrene (B[a]P). 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 3,3',4,4',5-pentachlorobiphenyl (PCB#126), while a concentration-dependent response of EROD activity in the epithelia was induced within 18-24 h when the apical side was exposed to these toxicants. The 24 h EC50 of EROD activity was 2.77 x 10(-7) M for PCB#126, 1.85 x 10(-7) M for B[a]P and 7.38 x 10(-10) M for TCDD. showing: that the preparation was not only sensitive to PAHs and dioxin-like compounds, but also able to produce inductive potency of AhR agonists that generally agreed with those derived from other established in vitro and in vivo systems. The results suggest, that the cultured gill epithelia from seawater-adapted tilapia may serve as a simple. rapid and cost-effective tool for assessing exposure and potential effects of toxicants in marine waters. (C) 2004 Elsevier B.V. All rights reserved.

The Chinese rare minnow (Gobiocypris rarus) as an in vivo model for endocrine disruption in freshwater teleosts: a full life-cycle test with diethylstilbestrol

Chinese rare minnow (Gobiocypris rarus), a freshwater teleost,. was exposed to diethylstilbestrol (DES) at 0.05, 0.5, 1 and 5 mug/L from fertilized eggs for up to mature period under flow-through condition. Several endpoints that related to development, reproductive fitness and transgenerational effects were evaluated. It was found that body length and body weight were significantly reduced and vitellogenin (Via) levels were significantly increased for fish exposed to DES. Histological examination showed that the sex ratios of F-0 fish skewed to female and about 2% of the fish exposed to 0.05 mug/L DES developed testes-ova. The reproductive success, as determined from data on egg production, was reduced in female fish exposed to 0.05, 0.5, 1 and 5 mug/L DES. The lowest-observed-effect concentrations (LOEC) for chances of sex ratios, reproductive success and histology alteration of F-0 are 0.05 mug/L. In the offspring, transgenerational effects on egg hatching rate. egg fertilization and Vtg levels of juvenile individuals were not observed. However. survival of F, generation fry significantly declined. The analysis of sex steroid levels revealed a significant decrease of testosterone (T) in the whole body homogenates (WBH) of male progeny and somewhat elevation of estradiol (E-T) in the WBH of female offspring. These findings indicate that exposure to DES causes a variety of developmental, reproductive and transgenerational effects. (C) 2004 Elsevier B.V. All rights reserved.

海洋动能及其开发

海洋面积占地球总面积的71%，蕴藏着丰富的海洋能源。海洋能包括海水温差、海水盐度差、潮汐、潮流、海流、波浪等形式。本文仅就储量丰富又有特色的海洋动能及其开发作一综述。 一、海洋动能的形式 动能形式指海流、潮流和波浪能。 1.海流 海水朝一定方向以一定速度不

D2-4放线菌的筛选及其抗生物质研究

利用有益微生物及其代谢产物来防治植物病害，已成为一个十分活跃并具有巨大应用前景的领域。本论文采用土壤预处理等特殊方法，从长白山不同高度的土壤中筛选出1068株放线菌。通过对峙培养法和杯碟法，筛选出D1-1等10株对蔬菜病害菌具有抑制作用的菌株。离体叶片实验中发现D2-4发酵液对黄瓜、辣椒、番茄等蔬菜真菌病害具有一定的防治效果。以水和常用化学农药作为空白和药物对照，对D2-4发酵液进行了盆栽实验，结果对番茄灰霉、辣椒根腐和黄瓜枯萎病的防治效果分别为70.65％、63.27％、65.04％，初步显示出良好的防治效果。通过单因素和均匀设计实验，优化了DZ-4菌发酵培养基的组成，考察了培养时间、接种量、菌龄等对抑菌活性的影响。确定了最佳发酵培养基成分：黄豆饼粉1.10％、葡萄糖2.71％、蔗糖1.00％、NaCl0.10％、酵母膏0.10％、发酵培养基初始pH为6.61。最佳发酵时间为96h左右，培养20～24h的种子液以7％的接种量转接有利于提高抑菌活性。经发酵培养基和发酵条件的优化，发酵液抑菌活性达到了6588 u／ml，比原始发酵培养基（3678 u／ml）活性提高了79.12％。经发酵液的预处理、离子交换层析、吸附柱层析、高效液相色谱纯化等步骤，对D2-4抗生素进行了分离纯化研究。通过纸层析、纸电泳等试验最后确定该农用抗生素为弱碱性水溶性抗生素。对D2-4抗生素纯品进行了红外吸收光谱、紫外吸收光谱等理化性质的研究。

CO_2浓度升高对玉米叶片光合生理特性的影响

以沈糯3号为研究材料,利用开顶式气室(OTCs)法研究了二氧化碳(CO2)浓度升高处理下,玉米叶片叶绿素含量、光合生理特性及其子粒产量的变化,揭示CO2浓度升高对玉米光合生理特性及子粒产量的影响机理。结果表明,在整个生育期内,与对照相比,高浓度CO2处理下,玉米叶片叶绿素a、叶绿素b及叶绿素(a+b)的含量增加,而叶绿素a/b的值则先升高后降低;在整个处理期间,净光合速率均高于对照(p>0.05),升高幅度为12.6%～71.1%,气孔导度低于对照(p>0.05),其降低幅度为2.9%～18.8%。处理至抽雄期和灌浆期,胞间CO2浓度分别增加152%和161%,均极显著高于对照(p<0.01);蒸腾速率的变化较小。高浓度CO2处理下,玉米穗粒数和穗粒重均明显高于对照(p<0.05)。CO2浓度升高在一定程度上促进了玉米的光合作用,从而使玉米子粒产量增加。

不同土地利用方式下沙地土壤水分空间变异规律

利用地统计学的方法 ,研究了科尔沁沙地甸子地不同土地利用方式草地和玉米地春季土壤含水量的空间变异规律。结果表明 ,草地表层、亚表层土壤含水量的变异函数均可很好地拟合成球状模型 ,具有明显的空间结构特征 ,其空间相关度分别为 0 979、0 999,变程分别为11 5 7m、19 4 1m ,分数维分别为 1 5 71、1 5 35 ,Moran’sI系数表现为在近距离内 (0 5～ 2 5m)为较强的正相关 (I=0 3～ 0 8) ,随着距离的增大 ,相关性变小 ,>5m后表现为较弱的负相关(I =0 2 )的变化趋势 ,克立格制图均表现出中央和四周高 ,西北角存在明显过渡带的空间分布格局 ,表层和亚表层具有很大的相似性。而耕地表层、亚表层土壤含水量变异函数分别拟合成线性和球状模型 ,其空间相关度分别为 0 344、0 914 ,变程分别为 7 6 7m、9 31m ,分数维分别为 1 92 8、1 6 81,Moran’sI系数分析和克立格制图表明表层、亚表层土壤含水量存在明显的差异。因此草地和耕地土壤含水量变异函数模型及参数、分数维、Moran’sI系数和克立格制图均存在明显的区别。同草地相比 ,玉米地土壤含水量空间格局特征表现为空间依赖性小 ,随机性大 ,空间自相关作用范围小 ,破碎化程度高。所以有必要采取退耕还草的措施来保护和恢复沙地生态系统的健康。

抗番茄灰霉病菌农用抗生素D2-4发酵条件的研究

对拮抗番茄灰霉病菌的D2 -4菌株培养基成分和发酵条件进行了研究。经研究发现在28℃ ,180r·min -1条件下 ,最佳发酵时间为96h左右 ,培养20～24h的种子液以7 %的接种量转接有利于提高抑菌活性 ,装液量为60mL/250mL三角瓶 ,均匀设计试验得出,最佳培养基配方为:黄豆饼粉1.10 %、葡萄糖2.71 %、蔗糖1.00 %、NaCl0.10 %、酵母膏0.10 %、pH值6.61。

天然物质复配铁型絮凝剂及其处理味精废水的研究

采用不同天然物质(城市草炭土、草甸土、火山灰和红壤)与聚合硫酸铁复配,制备一种更为经济的新型絮凝剂,利用其对高浓度有机味精废水进行絮凝实验,并讨论了各组分的不同投加量比例及其絮凝的影响因素.研究结果表明:此种天然物质-聚合硫酸铁复配絮凝剂处理味精废水表现出优良的絮凝性能.其中以草甸土、红壤为天然复配材料处理效果最为显著,其最佳投加量比例为草甸土(g)∶聚合硫酸铁(m l)∶助剂(g)=11∶4∶6,最佳pH为7.0—8.0;红壤(g)∶聚合硫酸铁(m l)=10∶6,最佳pH为1.0—2.0.在此条件下,该天然复配铁型絮凝剂对味精废水的CODcr去除率远远高于聚合硫酸铁(PFS)本身,分别可达到71.1%和55.0%.

Gas sensitivity of composite Langmuir-Blodgett films of Fe2O3 nanoparticle-copper phthalocyanine

The Langmuir-Blodgett (LB) composite films, ferric oxide nanoparticle composite with tris-(2,3-di-t-amylphenoxy)-(8-quinolinolinolyl) copper phthalocyanine (CuPcA(2)), were obtained by capped type and alternated type and characterized by X-ray photoelectron spectroscopy (XPS) and visible spectra. The gas sensitivity of the composite films and the pure ferric oxide and pure CuPcA(2) LB films to ammonia and ethanol were measured at room temperature. The composite films could be used as the C2H5OH sensors in the range of 2-8 or 100-200 ppm. The XPS data suggested that the adduct complex NH3-CuPcA(2) was formed after the capped film was exposed to the detected gas of ammonia. (C) 2000 Elsevier Science B.V. All rights reserved.