作者机构：
[Li, Juan] College of Life Sciences, Central China Normal University, Wuhan, Hubei, China;[Liu, Yong-Ding] Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China;[Zhang, Cheng-Cai] College of Life Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei, China;[Xu, Wen-Liang] College of Life Sciences, Central China Normal University, Wuhan, Hubei, China<&wdkj&>Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China
通讯机构：
[Liu Yong-ding] I;Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China
摘要：
ThefecC gene encoding a putative iron (III) dicitrate transporter was cloned from nitrogen-fixing cyanobacteriumAnabaena sp. PCC 7120, and inactivated. The mutant grows normally in medium with NO 3 ? , NH 4 + or without combined nitrogen. But in iron-deficient medium, the mutant grows slowly. Photosynthetic properties were compared between the mutant and the wildtype strain, the content of photosynthetic pigments in the mutant is lower than that of the wild-type. The results of RT-PCR experiments show that thefecC gene is expressed under iron-deficient conditions, but is not expressed under iron-replete conditions. These results revealed thatfecC gene product is required for optimal growth under iron-deficient conditions inAnabaena sp. PCC 7120. Key words Anabaena sp. PCC 7120 - fecC - iron deficiency - photosynthetic properties - expression CLC number Q 933 Foundation item: Supported by the National Natural Sciences Foundation of China (30070154), the Frontier Science Projects Program of the Institute of Hydrobiology, the Chinese Academy of Sciences (220316), State Key Project on Cyanobacterial Bloom Control in Lake Dianchi (K99-05-35-01) Biography: XU Wen-liang (1974-), male, Ph. D, research direction: molecular genetics of cyanobacteria.
作者机构：
[Xiong, L] Cent China Normal Univ, Coll Life Sci, Wuhan 430079, Peoples R China.;Jiangsu Univ, Sch Med Technol, Zhenjiang 212001, Peoples R China.;Chinese Acad Sci, Inst Hydrobiol, Wuhan 430072, Peoples R China.
通讯机构：
[Xiong, L] C;Cent China Normal Univ, Coll Life Sci, Wuhan 430079, Peoples R China.
关键词：
cypermethrin;Daphnia magna HB;toxicity
摘要：
The acute toxic effect of the pesticide cypermethrin to Daphnia magna HB was examined. D. magna HB was exposed to cypermethrin at concentrations of 0, 1, 3, 5, 7, and 9 mg/L for 24 h. Data showed that the 24 h-LC50 of cypermthrin on D. magna HB was 4.81 mg/L. In contrast, the 24 h-LC50 of K2Cr2O7(the national standard toxicant) to Daphnia magna was 0.38 mg/L in the current study. Results indicated that the Daphnia magna was very sensitive to pesticides. In addition, the effects of the culture condition(such as hardness, temperature and DO etc.) on Daphnia magna HB was also studied.
