Organoclays for controlled release of the herbicide fenuron

Organoclays were assayed as matrices in which to associate herbicides, with the aim of decreasing product losses that could give rise to water contamination from agricultural activities. Fenuron was selected as model of a very mobile and highly water-soluble herbicide. Two different organoclays of high (A-HDT) and low (H-C18) reversible fenuron sorption were selected. Herbicide-organoclay complexes were prepared from the two organoclays and with two different fenuron contents (20 and 40 g AI kg-1) and two different mixing times, so as to form a series of weak and strong complexes. The release of fenuron from those complexes into water and water/soil suspensions gave values of T50 (time to release 50% of the fenuron content) ranging from 0.3 min to 2400 h. The total fenuron released in these closed systems ranged from 48 to 80% of the fenuron in the complex. The organoclay type (high or low sorptivity) had the greatest influence on fenuron release, followed by the strong or weak complex, suggesting that herbicide-organoclay interactions are the main factors controlling release. Soil column leaching experiments showed fenuron-organoclay complexes to be effective in reducing the peak herbicide concentration in the leachate to a half (6 microns) or a quarter (3 microns) of that obtained from the free technical compound (12 microns). Herbicide lost through leaching was reduced from 78% for the free technical fenuron to 50-30%, depending on the organoclay used as carrier and the strength of the complex. Bioassay with ryegrass showed that the weak fenuron/H-C18 complex (40 g AI kg-1) gave the same herbicidal activity as technical fenuron. The potential suitability of low-sorptive organoclays for conferring slow-release properties on the fenuron complex has been demonstrated.     

白水江国家级自然保护区高等植物多样性测定及保护研究

在白水江国家自然保护区综合考察的基础上,应用Shannon—Wiener变化度指数（H）、Pielou均匀度指数㈣和Simpson优势度指数（功测度群落内的多样性（α多样性）,用Sorensen指数（S1）、Jaccard指数（Cj）和Cody（βc）指数测试群落间的多样性（β多样性）结果表明：保护区由于海拔相差大和所处气候带的原因,仅多样性与β多样性均较低;保护区有野生种子植物136科、708属、1810种。各种温带分布的属共有540个之多,占总属数的70．77％,温带成分几乎包括了世界温带分布的所有木本属,反映出明显的温带性质。并针对存在的生境片断化、毁林开荒、森林不合理砍伐、森林旅游等威胁因素,提出了相应的保护措施。     

天津市民水资源保护意识定量评价

水资源是维持人类生存、经济发展与社会进步的重要物质。但随着人口增长和社会经济的快速发展,水资源短缺和水污染问题日益严重。加强水资源保护意识宣传,提高市民节水意识,是实现水资源可持续利用的重要途径。文中基于系统观念,建立了一套综合评估市民水资源保护意识的指标体系,针对天津市民开展实证研究。选用层次分析法确定指标权重,通过模糊综合评价模型进行定量评价,采用相关分析辨识主要影响因子。结果表明:天津市民水资源保护意识总体一般,水资源保护意识强、中、弱的市民比例分别为50.96%、37.77%和10.92%;不同特征人群水资源保护意识存在差异;基于ArcGIS的空间分析表明天津市民水资源保护意识水平存在"东南高西北低、内高外低"的分布规律。     

应用TaqMan-MGB探针进行松材线虫的实时荧光定量检测技术研究

 松材线虫是国际公认的最重要的检疫性有害生物之一,也是我国2类检疫危险性有害生物,我国口岸多次从货物的木质包装中截获该线虫。由于松材线虫与拟松材线虫在形态上极其相似,难以区分,幼虫更无法用于鉴定。传统的形态学鉴定、生化以及其他分子技术等方法存在费时、准确度不高、灵敏度低等缺点,不易形成标准。我们设计筛选一对引物以及一条MGB探针,对松材线虫进行实时荧光PCR检测。建立了一条从1 pg到10⁴pg标准曲线,相关系数r=0.965。该检测方法省时、准确、快速、无污染。     

Epidermal proteases of the Japanese eel

A fluorescent-sensitive assay was used to demonstrate the protease activity in the dorsal skin of Japanese eel (Anguilla japonica). Two distinct extracts were separately prepared from skin mucus and epidermal cell layers, with no mutual contamination. The epidermal extract was sensitive to various substrates, whereas there was no, or only marginal, susceptibility to the same substrates for the mucous extract. Optimum hydrolysis pHs of the epidermal extract was variable and below pH 7.0, and the optimum hydrolysis temperatures were between 40 and 50 °C. In addition, Tos-Phe-Ch₂Cl, chymostatin, CdCl₂, CuCl₂, HgCl₂ and ZnCl₂ inhibited protease activities to different extents. Several other reagents specifically affected the protease activities, and their induced effects were useful for the identification of epidermal proteases. The findings indicate that a proteolytic factor, exhibiting various enzymological specificities, is retained within epidermal cell layers of Japanese eel. This factor is composed of 4 distinct proteases, such as cathepsins L and B-like proteases, a serine protease and an aminopeptidase.     

生态旅游区资源评价与保护性开发

以东北东部的主要生态旅游区——方正原始森林生态旅游区为例，根据最新国家标准，对旅游区的旅游资源进行了调查、分类和评价。结果表明：其自然景观良好，原始性很强，适合开展生态旅游。对该区进行保护性开发，在功能分区与景区、景点规划方面要以环境保护为前提，同时提出了旅游区环境保护监测系统及生态环境建设的相关建议，以保证生态旅游的真正实现。     

苏云金芽孢杆菌对黄河鲤血液免疫效果研究

研究了苏云金芽孢杆菌对黄河鲤血液免疫应答的影响.将苏云金芽孢杆菌按1.0×10~(11)、3.0×10~(11)、5.0×10~(11) cfu/kg 3个浓度添加在鱼用全价颗粒饲料中,投喂经嗜水气单胞菌疫苗免疫组(A_0～A_3)和未免疫组(B_0～B_3)黄河鲤,分别于0、15、30、40 d时检测各组黄河鲤白细胞吞噬活性、血清溶菌酶活性以及血清凝集抗体效价,并进行攻毒试验.结果表明:添加苏云金芽孢杆菌可使黄河鲤血液中白细胞吞噬活性和血清溶菌酶活性显著提高.添加组与对照组差异显著(P<0.05),添加浓度越高,血液白细胞活性和溶菌酶活性越强.免疫组与未免疫组白细胞吞噬活性差异不显著(P>0.05),而溶菌酶活性差异显著(P<0.05).在停止投喂后10 d,白细胞活性、血清溶菌酶活性逐渐下降,但差异不显著(P>0.05).添加苏云金芽孢杆菌还可提高黄河鲤的凝集抗体效价及攻毒后的存活率,其中,当菌株添加浓度为5.0×10~(11) cfu/kg时,受免疫的黄河鲤免疫保护率最高.即投喂苏云金芽孢杆菌对黄河鲤血液免疫应答有明显促进作用.     

中国海洋生物多样性保护研究进展与几个热点问题

根据近年最新研究成果,对中国海洋生物多样性保护和研究进展进行了综述。文章重点阐述了海洋生物遗传多样性、物种多样性和生态系统多样性状况、保护现状及其研究进展,分析了目前海洋生物多样性保护所面临的主要威胁;探讨了近期中国海洋生物多样性保护研究的几个热点问题。     

Presence of anti-Neoparamoeba sp. antibodies in Tasmanian cultured Atlantic salmon, Salmo salar L

Previous studies have indicated that when Atlantic salmon, Salmo salar L., are exposed to Neoparamoeba sp. the fish produce anti-Neoparamoeba sp. antibodies. It appears unlikely that these antibodies elicit any specific protection against amoebic gill disease (AGD) as fish with demonstrable activities have been affected by AGD. Experiments were conducted on Atlantic salmon cultured throughout Tasmania to assess the natural production of antibodies towards Neoparamoeba sp. Fish were sampled from areas where AGD was prevalent and from areas where there had been no reported cases. An enzyme-linked immunosorbent assay (ELISA) was used to measure anti-Neoparamoeba sp. antibody activities in serum. All fish from sea water had antibody activities greater than the negative control fish, including fish from areas with no reported cases of AGD. Time trial samples indicated that time after transfer to sea water did not appear to be a significant (P > 0.05) factor in antibody activity, however location was (P < 0.05). There was no agreement (corrected kappa value, 0.16) between the ELISA result and the isolation of Neoparamoeba sp. from the gills of the same fish. The results suggest that Atlantic salmon in seawater culture in Tasmania produce anti-Neoparamoeba sp. antibodies regardless of infection history, suggesting the presence of Neoparamoeba sp. in the environment.