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巢湖沉积植硅体组合及中全新世以来的环境演变 总被引：1，自引：0，他引：1
尽管以前对眼虫进行过大量的形态发育研究和基于核糖体RNA基因的系统发育分析,但对于株系之间的关系仍然知之甚少．因其形态特征有限并且易变,很难鉴定眼虫的相似种和同种内不同的株．作者利用微卫星DNA指纹图谱,在七株眼虫中扩增了七个微卫星DNA位点,成功扩增的六个微卫星引物都得到了四到八个条带．从微卫星DNA指纹图谱计算得到的相似性系数范围从0．000到0．957．根据相似性系数得到的树状结构,七株眼虫在距离为0．9346处分为三支:E．mutabilis,E．intermedia和E．gracilis．其中,五株E．gracilis分为两组:来自日本的和美国的．不同地区的株得到不同的基因型,并初步分析了它们之间的关系．研究表明七株眼虫根据微卫星DNA指纹图谱被明显区分开．微卫星DNA指纹图谱具有很高的分辨率,是鉴定和区分原生动物相似种和同种内不同株的一种有用的新方法． 相似文献
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Direct effects of pure humic substance (BS1 FA) on three different aquatic organisms (Ceratophyllum demersum, Dreissena polymorpha, and Chaetogammarus ischnus) were demonstrated in this study. Exposure to environmentally relevant concentrations (0.5 mg/L) of this humic substance led to the activation of the microsomal and soluble glutathione S‐transferase (GST) in Ceratophyllum demersum. Exposure to 3‐chlorobiphenyl showed also an elevation of GST activity, which is due to the proposed detoxication metabolism of these chlorinated biphenyl. Coexposure to a mixture of 3‐chlorobiphenyl and BS1 FA showed a reduction of enzyme elevation, but still significant over an untreated control. The direct impact of humic substances seems not to be restricted to a specific class of organisms. 相似文献
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Controls on the nature and distribution of an alga in coal mine-waste environments and its potential impact on water quality 总被引：2，自引：0，他引：2
A dominant non-bacterial microorganism that may strongly impact environmental conditions in acid mine drainage at several
Indiana coal mine sites is a single-celled protozoan, Euglena mutabilis. Field data suggest E. mutabilis has high tolerance for elevated total dissolved solids (TDS), to 18 g/l, and acid conditions to pH 1.7. Distribution is restricted
to unmixed effluent pH<4.6, with prolific growth between pH 3.0 and 3.5. Additional factors influencing E. mutabilis include preference for areas with lower mineral/colloidal precipitation rates and a stable substrate of iron-rich precipitates.
Initial studies indicate that in areas of prolific growth it contributes to oversaturation of dissolved oxygen by up to 200%.
The presence of small orange intracellular crystalline-like structures, similar in color to iron oxyhydroxides, suggests that E. mutabilis may be sequestering iron, and possibly other metals. Further work is needed to determine if E. mutabilis contributes to natural mitigation of poor water quality at these and other coal mine sites.
Received: 13 January 2000 · Accepted: 2 May 2000 相似文献
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Although both Astasia longa and Euglena gracdlis belong to different genera, they share many morphological characters except that A. longa has no chloroplast. In the 1940‘ s, on the basis of the finding that in darkness or upon addition of scrne chemicals, E. gmcilis would fade reversibly or irreversibly, scrne scholars hypothesised that A. longa evolved from E. gracilis by losing chloroplast.The authors‘ use of RAPD and cladistic analyses in a study on the evolutionary relationship between A .longa and E. gmcilis showed that the A. longa ‘ s relationship with E. gmcilis was closer than that with other green euglenoids. This proves the hypothesis that A. longa evolved from E. gmcills is reasonable. The results d this study suggest that saprophytic colorless euglenoids were transformed fromgreen euglenoids by losing their choroplasts. 相似文献
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ANALYSIS OF EVOLUTIONARY RELATIONSHIP BETWEEN ASTASIA LONGA AND EUGLENA GRACILIS BY USING RAPD TECHNIQUE AND CLADISTIC ANALYSIS 总被引：1，自引：0，他引：1
ＩＮＴＲＯＤＵＣＴＩＯＮＡｓｔａｓｉａａｎｄＥｕｇｌｅｎａ,ｂｏｔｈｂｅｌｏｎｇｉｎｇｔｏＥｕｇｌｅｎａｐｈｙｔａ,ｗｅｒｅｆｉｒｓｔｃｌａｓｓｉｆｉｅｄｂｙＫｌｅｂｓ(1883)ｉｎｔｏｄｉｆｆｅｒｅｎｔｆａｍｉｌｉｅｓａｃｃｏｒｄｉｎｇｔｏｔｈｅｉｒｍｏｄｅｏｆｎｕｔｒｉｔｉｏｎ(ＡｓｔａｓｉａｉｓｓａｐｒｏｐｈｙｔｉｃａｎｄＥｕｇｌｅｎａｉｓｐｈｏｔｏｔｒｏｐｈｉｃ).Ｂｕｔｗｉｔｈｄｅｅｐｅｒｒｅｓｅａｒｃｈｅｓｏｎｉｔｓｍｏｒｐｈｏｃｙｔｏｌｏｇｙ,Ａｓｔａｓｉａｗａｓｆｏｕｎｄｔｏｂｅｖｅｒｙｓ… 相似文献
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I. N. Estcourt 《新西兰海洋与淡水研究杂志》2013,47(3):371-394
The distributions of 19 species of polychaetes burrowing in the intertidal sand and mudbanks of the Heathcote Estuary, New Zealand, are related to salinity, sediment grade, and length of time of exposure at low tide. Only Nicon aestuariensis Knox and Scotecolepides benhami Ehlers appear to be truly estuarine species reaching their greatest population densities in low salinities. Incidental observations of feeding and reproduction are reported. 相似文献
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NEW TAXA OF EUGLENOPHYTA FROM CHINA 总被引：1，自引：0，他引：1
施之新 《中国海洋湖沼学报》1995,13(4):348-353
Eight new taxa of Euglenophyta are described in this paper. They were collected from severalprovinces in China and respectively named Euglena allorgei var. exsulcata. E pisciformis var. globosa, E.tortiliS, Lepocinclis glabra var. papillata, Phacus pisiformis, Ph.strombuliformis,Ph.trimarginatus var.truncatus and Astasia angusta. 相似文献
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本文研究了北京翠湖湿地公园夏、秋季水华优势藻血红裸藻(Euglena sanguinea)从水华发生到衰亡过程的细胞密度、形态特征及其与环境因子的关系.结果发现,2016年8月下旬至9月中旬血红裸藻密度稳定增加,9月20日藻密度达到峰值5.13×106cells/L;9月下旬至11月底藻密度显著下降;血红裸藻在衰亡过程中呈现细胞形态由大变小、由细长变为圆形,细胞颜色由深变浅,运动速率由快变慢的趋势,衰亡后形成具透明胶被孢子的休眠体;血红裸藻群落生长的主控因子为水温和p H,其适宜的环境阈值范围为水温23~27℃,p H 7.3~8.0;其受光照强度影响存在分层现象,弱光强区域藻密度相对较低;血红裸藻的衰亡过程与铵态氮浓度呈显著正相关,低浓度时加速衰亡;与总氮浓度呈负相关,衰亡后总氮浓度显著升高;受总磷浓度影响相对较小,与溶解氧浓度无显著相关关系. 相似文献