150 resultados para 351
Resumo:
在滇西苍山采到的175种蝶类, 经鉴定隶属于8科89属。其中风蝶科分属20种 , 粉蝶科16属27种, 斑蝶科5属5种, 眼蝶科6属27种, 蛱蝶科16属31种, 蚬蝶科 2属6种, 灰蝶科21属28种, 弄蝶科16属30种。对其主要种类的垂直分布及区系 概况进行了分析。
Resumo:
在移栽有沉水植物的网箱和水泥池 ,放养不同规格和密度的河蟹 ,以定量研究河蟹对沉水植物的影响 ,进而探讨草型湖泊河蟹的养殖容量。草型湖泊对河蟹的养殖容量 (或负荷力 )可以定义为对水生植被的生长没有显著影响时的最大的河蟹现存量。通过河蟹放养密度与沉水植物相对生长率的分析 ,获得了不同规格河蟹的养殖容量。当年幼蟹规格较小 (壳宽 18 0± 1 2mm) ,其养殖容量为 2 3ind·m-2 ;二龄幼蟹 (35 0± 3 6mmCW )的养殖容量是0 9ind·m-2 ;较大规格河蟹 (6 0 0± 5 7
Resumo:
1996—1997年对扁担塘螺类优势种之一铜锈环棱螺进行了周年研究,结果表明其种群含四个年龄组,其中1996年组生长最快,其带壳湿重瞬时生长率为4.15,去壳干重瞬时生长率为3.40。采用瞬时生长率法测算其周年生产量为:带壳湿重,15.77g·m-2·a-1;去壳干重,0.8624g·m-2·a-1。P/B系数基本一致,分别为0.50,0.51。铜锈环棱螺的生产量的去壳干重(Wd,g·m-2·a-1)和带壳湿重(Ww,g·m-2·a-1)满足下列关系:Ww=17.20Wd。
Resumo:
本文研究了种植香蒲Typhaangustifolia或灯心草Juncuseffusus的人工湿地对城镇污水和人工污水污染物的净化效果,调查了香蒲、灯心草不同季节的生长差异及高浓度污水冲击负荷对其生长的影响.香蒲、灯心草人工湿地净化城镇污水,出水水质总体上达到国家Ⅱ、Ⅲ类地面水标准;灯心草湿地对人工污水中凯氏氮、总磷、化学耗氧量的去除率维持在94%以上.氨氮的去除率为82.7%-99.7%;在正常条件下,香蒲湿地夏季对凯氏氮、氨氮的去除率在96%以上,冬李明显低于其它李节(P<0.05).对总磷,化学耗氧量
Resumo:
对东湖9个湖区藻类的群落结构、生长潜力、初级生产力和营养状况进行了比较研究。结果表明,9个湖区藻类的种类组成无明显差异,绿藻为主,蓝藻和硅藻次之;藻类的生长潜力和初级生产力各湖区差异较大,均以茶港湾重污染区最高和牛巢湖最低。根据各项指标综合分析,9个湖区水质优劣的顺序是:牛巢湖、汤林湖、后湖、郭郑湖、菱角湖、筲箕湖、庙湖、喻家湖和茶港湾重污染区。对东湖的大水面郭郑湖40年来藻类的有关参数进行比较发现,藻类个体数量的峰值40年内增加了百倍以上,而藻类的属数却比50年代减少了一半,藻类多样性下降,种类小型化现
Resumo:
比较研究了鲫鱼异倍体细胞系(CAB-80)、团头鲂尾鳍细胞系(BCC)、大鳞副泥鳅雌核发育单倍体胚胎细胞系(PHG)、草鱼胚胎细胞系(GCE)、草鱼尾鳍细胞系(GCRF-2)、草鱼肾细胞系(GCK-84)及其四个克隆对草鱼呼肠孤病毒(GCRV)的敏感性。证实了这些细胞(PHG除外)在不同程度上对GCRV敏感,其中以GCK-84的敏感性最强。这表明,在体外培养条件下,GCRV并无严格的种族特异性。用经GCK-84传代的病毒感染草鱼种,能复制出典型的出血病症状。用GCK-84检测了病毒在GCK-84、GCRF
Resumo:
<正> 一、前言在工业废水排入水体时,除了要考虑卫生标准外,还必须注意废水对鱼类的毒害和因废水排入,以致水体原来的物理、化学条件的破坏,而影响到水生生物的生长和繁殖等问题。本文的目的是为了配合×××浮选厂的排水设计,提供有关该厂排出的废水对鱼类和枝角类毒害作用方面的资料。
Resumo:
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.