A phototaxis inhibition assay using barnacle larvae

The effects of sublethal concentrations of phenol and cadmium on the phototactic responses of the stage II nauplii of the barnacle Balanus amphitrite were investigated. Increased toxicant concentrations caused a reduction in phototactic responses. Balanus amphitrite nauplii exposed to nominal phenol concentrations of 100 ppm and higher for 1-12 h failed to exhibit phototactic responses, while longer exposure times of 24 and 48 h reduced the lowest observable effect concentration (LOECs) to 80 and 60 ppm, respectively. For cadmium, the LOECs, based on nominal concentrations, for B. amphitrite following 1, 6, 12, 24, and 48 h exposures were 20, 4.5, 4.0, 1, and 0.75 ppm, respectively. The LOECs can be significantly reduced by increasing the duration of exposure to the toxicants. A good relationship exists between the phototactic response and toxicant concentration as well as exposure time. Results of this study indicate that the toxicant-induced reduction in phototactic responses of barnacle larvae can be used in a sensitive, rapid screening test for ecotoxicological assessments. (C) 1997 by John Wiley & Sons, Inc.

Estradiol stimulates growth hormone production in female goldfish

The effects of estradiol (E(2)) on growth hormone (GH) production was investigated in gonad-intact female goldfish. It was first necessary to generate a specific antibody for use in immunocytochemistry, Western, and dot-blot analyses of GH production. To accomplish this, grass carp GH (gcGH) cDNA was cloned by the reverse transcription polymerase chain reaction (RT-PCR) and expressed in Echerichia coli and a specific polyclonal antibody to recombinant gcGH was generated in the rabbit. In Western blot, the anti-gcGH antibody specifically immunoreacted with recombinant gcGH, purified natural common carp GH, and with a single 21.5-kDa GH form from pituitary extracts of grass carp, common carp, goldfish, and zebrafish but not salmon, trout, or tilapia. Intraperitoneal injection of the recombinant gcGH enhanced the growth rates of juvenile common carp demonstrating biological activity of this GH preparation. Electron microscopic studies showed that the anti-gcGH-I antibody specifically reacted with GH localized in the secretory granules of the goldfish somatotroph. Using anti-gcGH-I in a dot-blot assay, it was found that in vivo implantation of solid silastic pellets containing E(2) (100 mu g/g body weight for 5 days) increased pituitary GH content by 150% in female goldfish. In a second, independent study employing a previously characterized anticommon carp GH antibody for radioimmunoassay, it was found that E(2) increased pituitary GH content by 170% and serum GH levels by approximately 350%. The E(2)-induced hypersecretion of GH and increase in pituitary GH levels was not associated with changes in steady-state pituitary GH mRNA levels, suggesting that this sex steroid may enhance GH synthesis at the posttranscriptional or translational level. Previous observations indicate that GH can stimulate ovarian E(2) production. The present results show that E(2) can in turn stimulate GH production, indicating the existence of a novel pituitary GH-ovarian feedback system in goldfish. (C) 1997 Academic Press.

STUDIES ON THE PURIFICATION AND RECLAMATION OF WASTE-WATER FROM A MEDIUM-SIZED CITY BY AN INTEGRATED BIOLOGICAL POND SYSTEM

The feasibility of an inexpensive wastewater treatment system is evaluated in this study. An integrated biological pond system was operated for more than 3 years to purify the wastewater from a medium-sized city, Central China. The experiment was conducted in 3 phases with different treatment combinations for testing their purification efficiencies. The pond system was divided into 3 functional regions: influent purification, effluent upgrading and multi-utilization. These regions were further divided into several zones and subzones. Various kinds of aquatic organisms, including macrophytes, algae, microorganisms and zooplankton, were effectively cooperating in the wastewater treatment in this system. The system attained high reductions of BOD5, COD, TSS, TN, TP and other pollutants. The purification efficiencies of this system were higher than those of most traditional oxidation ponds or ordinary macrophyte ponds. The mutagenic effect and numbers of bacteria and viruses declined significantly during the process of purification. After the wastewater flowed through the upgrading zone, the concentrations of pollutants and algae evidently decreased. Plant harvesting did not yield dramatic effects on reductions of the main pollutants, though it did significantly affect the biomass productivity of the macrophytes. The effluent from this system could be utilized in irrigation and aquaculture. Some aquatic products were harvested from this system and some biomass was utilized for food, fertilizer, fodder and some other uses. The wastewater was reclaimed for various purposes.

A colorimetric assay for screening microcystin class compounds in aquatic systems

Secondary metabolites produced by water-blooming cyanobacteria in eutrophic waters include some potent hepatotoxins, These compounds also have tumour-promoting properties, attributable to their inhibition and activation of protein phosphatases and kinases respectively. The inhibitory effect of these toxins on protein phosphatases have been employed in a commonly used radiometric assay, involving the use of a P-32-labeled substrate, for the detection and quantitation of these compounds. This paper investigates and describes a colorimetric method in which the activity of protein phosphatase 2A is determined by measuring the rate of colour production from the release of yellow p-nitrophenol using p-nitrophenyl phosphate as the substrate. Results of this study suggest that the colorimetric protein phosphatase inhibition assay is a simple, inexpensive tool for screening substances that may have tumour-promoting characteristics in aquatic systems. The detection limit of the colorimetric method is comparable to the radiometric assay. (C) 1998 Elsevier Science Ltd. All rights reserved.

CO2浓度升高对三种树木叶片化学和舞毒蛾幼虫取食及生长的影响

探讨全球气候变化的生物学和生态学效应是当今生态学中的热点，研究大气CO2浓度升高对植物-昆虫相互作用关系的影响具有重要的理论和实践意义。本文使用开顶式气室（Open-top chamber，OTC）在野外条件下研究了CO2浓度升高对三种树木（小青杨、白桦和蒙古栎）叶片化学成分含量的影响，以及树木叶片品质变化对一种广食性森林昆虫（舞毒蛾）幼虫取食、生长发育和取食偏嗜性的影响。得出如下结果：（1）CO2浓度升高对3个受试树种叶片中的营养成分及次生代谢物含量均有显著影响，总体表现为氮含量降低，而碳氮比、非结构性碳水化合物、总酚和缩合丹宁含量增加。叶片中的化学成分含量可随时间发生显著变化，不同树种、甚至同一树种不同冠层高度的叶片对CO2浓度升高的响应强度也是不同的。叶片的干物质含量和比叶重对CO2浓度升高的响应不显著。（2）室内非选择性取食实验、室内选择性取食实验以及上树取食饲养方式下的多龄期取食实验，均发现高浓度CO2处理组内舞毒蛾幼虫的生长发育受到显著抑制。但对四龄舞毒蛾幼虫所进行的短期生物测定并未发现不同CO2浓度处理下幼虫的生长发育速率、对食物的取食率和转化率等昆虫营养指标存在显著差异。（3）叶片品质的降低是导致舞毒蛾幼虫生长发育受抑制的主要原因。但是总体上，CO2浓度升高导致的叶片品质变化并未显著影响幼虫的取食率和取食量。（4）舞毒蛾幼虫对不同叶片种类表现出清晰的取食选择性，这种选择性在其幼龄期就可表现出来。幼虫对小青杨上层叶片有最显著的偏嗜性，对蒙古栎下层叶片有最明显的拒食性。但是CO2浓度升高导致的叶片品质变化对舞毒蛾幼虫的取食选择性和寄主偏嗜行为并未产生显著影响。（5）检测出高浓度CO2处理组内舞毒蛾幼虫虫粪中含有浓度更高的植物次生代谢物质（总酚和缩合单宁），这很可能是昆虫整体生长发育受抑制的重要原因之一。

厚朴中α-葡萄糖苷酶抑制活性成分研究

本论文由三章组成。 第一章是关于厚朴中具有α-葡萄糖苷酶抑制活性成分的研究。凹叶厚朴的乙醇提取物显示了较强的α-葡萄糖苷酶抑制活性。为了确定其活性成分，在活性测试的指导下，通过溶剂萃取、树脂吸附和反复硅胶柱层析等分离方法从凹叶厚朴乙醇提取物中分离得到6 个生物碱，并用质谱和核磁共振等波谱方法分别鉴定为：木兰箭毒碱，木兰花碱，鹅掌楸碱，蕃荔枝碱，罗默碱和Lysicamine。应用小肠α-葡萄糖苷酶模型测定了它们对α-葡萄糖苷酶的抑制作用。其中，番荔枝碱和木兰箭毒碱对α-葡萄糖苷酶相对抑制活性最好，分别为60%和62%；其它四个生物碱成分对α-葡萄糖苷酶的抑制活性几乎相当，鹅掌楸碱为46%，罗默碱为51%，Lysicamine 为49%，木兰花碱为51%。 第二章报道了厚朴酚的衍生物及其对α-葡萄糖苷酶的抑制活性。根据糖苷酶抑制剂的结构特点，设计合成了一系列厚朴酚的衍生物。厚朴酚经过Mannich 反应和环氧化及开环反应制备了一系列衍生物，经活性测试发现衍生物活性与取代基关系较大，其中5,5′-diallyl-3-((bis(2-hydroxyethyl)amino)methyl)biphenyl-2,2′-diol 的抑制活性最高，为72%。 第三章综述了厚朴的化学成分及药理活性两个方面的研究进展。 The dissertation consists of three chapters. The first chapter is about the study on the constituents with α-glycosidase inhibitory activity from Magnolia officinalis. The EtOH extracts of M. officinalis Rehd. et Wils showed good inhibitory activity against α-Glucosidase. In order to determine the active compounds, bio-assay was used to guide the isolation. Six known alkaloids were isolated by solvent extraction and repeated silica gel column chromatography, and their structures were identified as liriodenine, anonaine, roemerine, lysicamine, magnoflorine and magnocurarine by spectroscopic methods. The inhibitory activity against α-Glucosidase of these alkaloids was measured with alvine screening model of α-glucosidase. Among them, lysicamine and liriodenine have the best inhibitory activity at 60% and 62%, respectively. The other four alkaloids have close inhibitory activity, from 46% to 51%. The second chapter is about the derivation of magnolol and the inhibitory a ctivity of the derivatives. Seven derivatives of magnolol were prepared by Manni-ch reaction, epoxidation followed by ring-opening reaction. Biological activity as say indicated the inhibitory activity was related to substituting groups. Among them, 5,5′-diallyl-3-((bis(2-hydroxyethyl)amino)methyl)biphenyl-2,2′-diol had the highest activity at 72%. The third chapter is a review on the progress of M. officinalis including chemical constituents and pharmacological activity.