水华蓝藻萃取物抑菌作用的实验研究

目的:探索水华蓝藻萃取物及其混合物对细菌的抑制作用。方法:采用水华蓝藻混合藻中铜绿微囊藻、浮游念珠藻、水华鱼腥藻及其混合藻的萃取物,分别植入细菌、大肠菌群,检测其抑茵率。结果:铜绿微囊藻、水华鱼腥藻、浮游念珠藻及其混合藻的萃取物均具有抑菌作用,其中以混合藻的抑菌率最大,可达42.80%～46.00%,抑菌率又随萃取物浓度的递升而增大;当浓度为10 mg/mL时,抑茵率为10.00%;20 mg/mL时为30.00%,30 mg/mL为50.00%。结论:聚集成水华蓝藻的铜绿微囊藻、水华鱼腥藻,浮游念珠藻及其混合藻萃取物,都有不同程度的抑菌作用,尤其是此三藻的混合藻的最大抑菌率又随萃取物的浓度递升而增大。抑菌能力依次为:铜绿微囊藻>水华鱼腥藻>浮游念珠藻。     

藻毒素的检测与生物学效应评价的研究进展

对藻毒素的化学结构和化学特性、藻毒素的检测及藻毒素的生物学效应评价等方面研究进展进行综述：(1)藻毒素的种类、结构及特性等尚未完全清楚，需做进一步研究；(2)藻毒素的检测方法主要有生物法、化学法和免疫法等三大类；(3)现有生物学效应评价多为单因素单方法评价，主要分为观察法和实验法两大类。     

水样预处理法分离溶藻细菌效果观察

目的:探讨如何从水华期采集的水样中有效地分离溶解蓝藻的细菌.方法:从富营养化池塘中采集表层水样,采集的水样分3等份,分别进行如下处理:①经0.8 μm纤维滤膜过滤处理.②0.22 μm纤维滤膜过滤,氯仿剧烈震荡处理5 min.③103.42 kPa、121.5℃条件下灭菌20 min.将3种处理水样分别与液体培养供试蓝藻共培养,通过溶藻试验、富集培养和平板划线法筛选溶藻细菌.结果:筛选出7株能够抑制供试蓝藻生长或者溶解供试蓝藻的细菌.结论:本方法能有效地分离溶藻细菌,值得推广.     

Individual and combined effects of cadmium and copper on the growth response of Chlorella vulgaris

The individual and combined effects of cadmium and copper on the growth response of the green alga, Chlorella vulgaris, were examined. The effects of pH alone, and in combination with copper were also evaluated. An increase in cadmium and copper concentrations caused a significant reduction in the growth of C. vulgaris cells, and the corresponding EC₅₀ values were 1.02 and 4.01 mg L⁻¹, respectively. For a pH range of 2–7, the inhibitory effect due to increased copper concentrations (coupled with the resulting drop in pH) was significantly higher than the impact due to increased acidity (by addition of HCl) alone. At lower metal concentrations (5 mg L⁻¹ Cu + < 2 mg L⁻¹ Cd or 2.5 mg L⁻¹ Cd + < 4 mg L⁻¹ Cu), a combination of copper and cadmium appeared to have a stronger inhibitory effect on cell growth than that of a single metal. In contrast, at higher metal concentrations (5 mg L⁻¹ Cu + > 2 mg L⁻¹ Cd or 2.5 mg L⁻¹ Cd + > 4 mg L⁻¹ Cu), the effect of a single metal exhibited a significantly stronger effect compared to a combination of the two metals. ©1999 John Wiley & Sons, Inc. Environ Toxicol 14: 347–353, 1999     

A Screening Strategy for Selection of Anti-HSV-1 and Anti-HIV Extracts from Algae

In order to find new sources of antiviral agents with different mechanisms of action, extracts of 49 algae were assayed for antiherpes simplex virus (HSV) and anti-human immunodeficiency virus (HIV) activities. Twenty-five aqueous extracts showed anti-HSV activity, four of which were found to be most potent inhibitors with a selective index more than 1000. Eight samples of the aqueous extracts were identified as having activity against HIV replication. The result suggests that the extracts from algae are a promising source of antiviral agents which may act on different stages in virus replication cycle.     

Screening of marine algae for potential tyrosinase inhibitor: those inhibitors reduced tyrosinase activity and melanin synthesis in zebrafish

In order to find new anti-browning and whitening agents in this study, we investigated 43 indigenous marine algae for tyrosinase inhibitory activity. The extracts from Endarachne binghamiae, Schizymenia dubyi, Ecklonia cava (EC) and Sargassum silquastrum (SS) evidenced potent tyrosinase inhibitory activity similar to that of positive control, kojic acid. Among those marine algae, EC and SS are distributed abundantly on Jeju Island. Therefore, we selected those two species for further studies. Our results evidenced that both species reduced cellular melanin synthesis and tyrosinase activity. On the other hand, we utilized zebrafish as an alternative in vivo model. All the tested samples evidenced excellent inhibitory effects on the pigmentation of zebrafish, most likely due to their potential tyrosinase inhibitory activity. In simultaneous in vivo toxicity tests, no toxicity was observed in either algal species, on the other hand, toxicity was observed in positive controls. These results provided that EC and SS extract could be used as an ingredient for whiting cosmetics and that zebrafish is an alternative in vivo model.     

上海淀山湖、黄浦江水系浮游藻类及藻类毒素的动态研究

通过对淀山湖、黄浦江水系浮游藻类的种群构成和蓝藻毒素的季节变化进行周年监测，发现淀山湖藻类及其毒素的污染具有明显的季节性，７～９月份蓝藻大量繁殖，形成了一年中污染的高峰。优势种群已由隐藻被毒性较高的蓝藻所取代，而蓝藻中占优势的铜绿微囊藻、水华鱼腥藻等能产生一种具有强烈肝毒性的短肽，称为微囊藻毒素。应用ＥＬＩＳＡ方法对淀山湖水中的微囊藻毒素进行测定，结果表明水体中微囊藻毒素与蓝藻的变化规律呈正相关，夏、秋季水中毒素出现高峰，最高值达５５．４ｎｇ／ｍｌ，说明淀山湖藻类毒素的污染较为严重。通过对水体总磷、总氮、叶绿素ａ、ｐＨ值等因素的分析，讨论了影响该水系营养水平和藻类生长的主要因素。     

Sargassum plagiophyllum Extract Enhances Colonic Functions and Modulates Gut Microbiota in Constipated Mice

Constipation is a symptom that is widely found in the world’s population. Various dietary supplementations are used to relieve and prevent constipation. Seaweed is widely used for its health benefits. In this study, we aimed to investigate the effects of Sargassum plagiophyllum extract (SPE) on functions of the gastrointestinal tract and gut microbiota. The results show that SPE pretreatment increased the frequency of gut contraction, leading to reduce gut transit time. SPE pretreatment also significantly increased the secretion of Cl⁻ and reduced Na⁺ absorption, increasing fecal water content in constipated mice (p < 0.05). In addition, the Bifidobacteria population in cecal contents was significantly higher in constipated mice pretreated with 500 mg/kg SPE for 14 days than in untreated constipated mice (p < 0.05). Our findings suggest that SPE can prevent constipation in loperamide-induced mice. This study may be useful for the development of human food supplements from S. plagiophyllum, which prevent constipation.