981 resultados para 366.223


Relevância:

10.00% 10.00%

Publicador:

Resumo:

报道了一种新的高效低能耗的污水处理塘系统的中试研究结果.本生物塘系统分为三个功能区域,分别为污水净化区,水质修饰区和综合利用区.水生维管束植物呈带状分布于塘系统中,在时间上和空间上进行不同搭配组合.较之传统氧化塘和一般的水生植物塘、综合生物塘的处理效果较好,COD、BOD、TSS、氮、磷等污染组分去除效率较高,细菌,病毒及诱变活性明显下降。在污水净化的同时,收获大量的水生植物及鱼,蚌等水产品.水质明显改善,出水可用于水产养殖和农业灌溉.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

在水质酸化和模拟酸雨试验中,共出现浮游动物17种,其中包括轮虫9种、枝角类6种和桡足类2种。在pH5.0—8.3各试验组出现种类数(10—13种)和个体数(223.0—334.5个·L~(-1))较多,而在pH3.0和4.5试验组出现种类数(5—9种)和个体数(16.8—182.0个·L~(-1))较少,表明pH5.0以下对浮游动物群落有明显的影响。从不同类群出现所占比例看,在pH5.5以下,随着pH的下降,存在着轮虫逐渐取代桡足类的趋势。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

本文以3种鱼类组织细胞系为材料,对鱼类微细胞和小分离细胞制备技术及其形成机制进行了研究。在微细胞制备中,观察了细胞的微核化过程,微核是由间期状态的细胞核不规则分裂而成。光镜和扫描电镜观察表明,在小分离细胞聚集体形成过程中,细胞核的变化与微细胞的微核化过程相一致,但其细胞质的分裂机制不同,当细胞质进行异常分裂的同时,细胞的微核也随同细胞质不规则分裂而被分配至各个小分离细胞内。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

由蒙金娜培养基上分离获得了东湖中的屈挠杆菌。研究了其中4个代表株的生物学特性,并与中华屈挠杆菌、加拿大屈挠杆菌、皮纳屈挠杆菌等3种屈挠杆菌的模式株作了比较和数值分类,讨论了屈挠杆菌在水生态系统中的作用、分离方法及其应用前景。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

柄杆菌对固氮蓝藻生物量和色素的影响研究结果表明:多态柄杆菌(Caulobacter polymorphus)017-41或新月柄杆菌(Caulobacter creseentus)CB_2的活菌、死菌及破碎细胞悬液分别与鱼腥藻(Anabaena)、念珠藻(Nostoc)不同藻珠混合培养时,试验组生长量均优于对照组;对衰老黄化的藻培养物的生长刺激作用尤为显著;试验组藻培养物的藻蓝或藻红素含量亦明显高于对照组。其作用机理尚待进一步阐明。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

<正> 本文报道的是1981年5—6月在鄂西地区(包括五峰、宜都、宜昌、当阳、兴山及神农架林区)采集到的裸藻门植物5个新种,7个新变种和3个新变型。1.阿洛格裸藻头状变种(新变型) (图1:a—e)Euglena allorgii var.capitata shi, var. nov.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

在恒温条件下,观察了平突船卵潘、隆线溞、微型裸腹溞的生长和繁殖。这三种淡水枝角类的生长随龄数的增加而变慢;总生活时间随温度升高而缩短。 平突船卵溞在20℃时,有3个幼龄、18个成龄、总生活时间为46.8天;30℃时为3个幼龄、15个成龄和18.8天。30℃时,隆线溞有3个幼龄、14个成龄、总生活时间为18.7天;微型裸腹溞则为2个幼龄、9个成龄和10.7天。 种类不同,累计产卵数相差很大。隆线溞在30℃时高达366个;微型裸腹溞仅为48个。平突船卵溞在20℃和30℃时分别为178个和172个。产卵率以隆线

Relevância:

10.00% 10.00%

Publicador:

Resumo:

作者观察了淡水青虾在实验室条件下幼体发育的情况。在幼体发育的全过程中,有的个体蜕皮9次,有的蜕皮11、14次。本文是描述蜕皮9次的个体的发育情况。从第一至第九期幼体以及后期幼体都附有详细的附肢图和部分整体图。幼体发育所需的时间随水温而变,在26.5±1.3℃条件下,幼体完成变态达到后期幼体需21天,在30.9±1-2℃仅需16天。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper discusses various techniques that may be used to combat counterfeiting in the pharmaceutical supply chain. These include the use of electronic pedigrees (to ensure the integrity of the supply chain), together with mass-serialization (to provide for a unique lifecycle history of each individual package) and authentication of the product (to check for any discrepancies in the various attributes of the product and its packaging are as intended for that individual package). Management of the pedigree process and product authentication is discussed in some detail, together with various other learnings from the Drug Security Network, including identification of some remaining vulnerabilities and suggestions for tightening these loopholes. © 2008 Springer-Verlag Berlin Heidelberg.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

<正> 白鲢,东北地区又称胖头,在黑龙江流域内分布很广。黑龙江中下游、松花江、嫩江等干流中都很丰盛,黑龙江上游呼玛以上的水体中,则尚未见其棲息。本文是根据1957—1958两年内,黑龙江流域渔业考察队在上述地区所采的标本和野外观察的新鲜材料共约70多尾,而整理分析的。白鲢是一种闻名的淡水饲养鱼,生长迅速,市上常见的大小多为2—7市斤,黑龙江中10斤和10斤以上的个体也十分多,下面是1958年4—8月从黑龙江、松花江、嫩江等地所采到的40尾白鲢的体重记录:

Relevância:

10.00% 10.00%

Publicador:

Resumo:

P>Semen sample was collected from two captive adult Yangtze finless porpoises (Neophocaena phocaenoides asiaeorientalis) during physical examination. One individual was aged about 9 years with body length 143 cm (total length) and body weight 46.1 kg in 2003. The age of the other was unknown and its body length was 147 cm and body weight was 43 kg in 2004. Ultrastructure of their spermatozoa was examined using scanning and transmission electron microscope. The sperm concentration was 4.17 x 10(9) spermatozoa per ml by the cytometer. The approximate dimensions of the spermatozoa were as follows: head length, 3.366 +/- 0.140 mu m (mean +/- SE, n = 15); head width, 1.896 +/- 0.099 mu m (n = 15); and neck length, 1.004 +/- 0.074 mu m (n = 10). The tail included midpiece, principal piece and terminal piece. The length of the midpiece was 1.882 +/- 0.077 mu m (n = 9). There is no apparent boundary between the principal piece and the terminal piece, so the length of the principal piece and the terminal piece was 44.612 +/- 3.485 mu m (n = 5). Total length of the spermatozoa was 53.314 +/- 4.580 mu m (n = 10). The acrosome covered approximately 45.8% of the anterior portion of the head.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Vasa is essential for germline development. However, the precise processes in which vasa involves vary considerably in diverse animal phyla. Here we show that vasa is required for primordial germ cell (PGC) migration in the medakafish. vasa knockdown by two morpholinos led to the PGC migration defect that was rescued by coinjection of Vasa RNA. Interestingly, Vasa knockdown did not alter the PGC number, identity, proliferation and motility even at ectopic locations. We established a cell culture system for tracing PGCs at the single cell level in vitro. In this culture system, control and morpholino-injected gastrulae produced the same PGC number and the same time course of PGC survival. importantly, vasa-depleted PGCs in culture had similar motility and locomotion to normal PGCs. Expression patterns of wt1a, sdf1b and cxcT4b in migratory tissues remained unchanged by Vasa knockdown. By chimera formation we show that PGCs from vasa-depleted blastulae failed to migrate properly in the normal environment, whereas control PGCs migrated normally in vasa-disrupted embryos. Furthermore, ectopic PGCs in vasa-depleted embryos also retained all the PGC properties examined. Taken together, medaka vasa is cell-autonomously required for PGC migration, but dispensable to PGC proliferation, motility, identity and survival. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A two-week trial was conducted to study the effect of feeding rates on heat shock protein levels in larval white sturgeon. The larvae (30 day post hatch, 230 mg initial body weight) were fed a commercial feed (12.6% moisture, 49.5% crude protein. 20.7% Crude fat, and 8.6% ash) at 5, 15. or 25% body weight per clay (BW d(-1)). Liver heat shock proteins (Hsp) were measured before and after the larvae were subjected to a heat shock from 18 to 26 degrees C at 1 degrees C/15 min and maintained at 26 degrees C for 4 h thereafter. Before heat shock, larvae fed 5% BW d(-1) had significantly (P<0.05) lower final body weight, RNA/DNA ratio, whole body lipid and protein content, and Hsp60 and Hsp70 levels but higher protein efficiency ratio, and whole body moisture content than larvae fed the two higher feeding rates. Heat shock significantly induced Hsp60 and Hsp70 levels in the liver of all fish but they were lower in larvae fed the 5% than those fed 15 and 25% BW d(-1). Hsp70 level increased much more than Hsp60 after the heat shock Suggesting that Hsp70 is a more sensitive biomarker under our experimental conditions. (c) 2008 Elsevier B.V. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Transgenic animals with improved qualities have the potential to upset the ecological balance of a natural environment. We investigated metabolic rates of 'all-fish' growth hormone (GH) transgenic common carp under routine conditions and during starvation periods to determine whether energy stores in transgenic fish would deplete faster than controls during natural periods of starvation. Before the oxygen uptake was measured, the mean daily feed intake of transgenic carp was 2.12 times greater than control fish during 4 days of feeding. The average oxygen uptake of GH transgenic fish was 1.32 times greater than control fish within 96 h of starvation, but was not significantly different from controls between 96 and 144 h of starvation. At the same time, GH transgenic fish did not deplete energy reserves at a faster rate than did the controls, as the carcass energy contents of the two groups following a 60-d starvation period were not significantly different. Consequently, we suggest that increased routine oxygen uptake in GH transgenic common carp over that of control fish may be mainly due to the effects of feeding, and not to an increase in basal metabolism. GH transgenic fish are similar to controls in the regulation of metabolism to normally distribute energy reserves during starvation. (c) 2008 Published by Elsevier B.V.