[Objective] The aim was to explore the relationship between alage-lysing bacterium and Anabaena flosaquae so as to provide reference for the control of bloom. [Method] An algae-lysing bacterium strain named S7 was iso...[Objective] The aim was to explore the relationship between alage-lysing bacterium and Anabaena flosaquae so as to provide reference for the control of bloom. [Method] An algae-lysing bacterium strain named S7 was isolated from eu- trophic river. The lyric efficiency and performing mode of S7 strain to Anabaena flos- aquae was studied. Influence of different environmental factors and the relationship between S7 strain and Anabaena flosaquae was also studied, and then the bacteri- um strain was physiologically identified. [Result] More than 90% of Anabaena flos- aquae had been removed by 7 d when the volume ratio of medium to algae solu- tion was 30%, the pH was 9 and the temperature was 35 ℃. These results also showed that a mutual inhibit relationship existed between S7 strain and Anabaena flos-aquae. The S7 strain killed the algae by indirectly through certain lyric agents in absence of direct contact with the target but by secreting metabolites. Moreover, these lyric agents also had the thermostability. 16SrDNA sequence analysis showed that S7 strain belonged to Chryseobacterium sp. [Conclusion] The examined Poly-p proved that S7 strain is polyphosphate accumulating bacteria （PAOs） and has better lyric efficiency.展开更多
This paper studied the effects of different ratios of nitrogen and phospho- rus on the growth and competition of Anabaena sp. strain PCC and chloralla vul- gads （low nitrogen-phosphorus ratio group： N/P=16：1; Mediu...This paper studied the effects of different ratios of nitrogen and phospho- rus on the growth and competition of Anabaena sp. strain PCC and chloralla vul- gads （low nitrogen-phosphorus ratio group： N/P=16：1; Medium low nitrogen-phospho- rus ratio group： N/P=32：1; Medium high nitrogen-phosphorus ratio group： N/P=64：1; High nitrogen-phosphorus ratio group： N/P=320：1）. Results suggested that the largest amount of anabaena sp.strain PCC survived in medium high nitrogen-phosphorus ratio group. The nitrogen-phosphorus ratio showed no significant influences on the growth of Chlorella vulgaris, but it exerted dramatic influences on the growth of Chlore/la vulgaris of the mixed cultivation system. The largest amount of Ch/orel/a vulgaris can be found in the medium-high nitrogen-phosphorus ratio group. The inhi- bition parameter of nitrogen-phosphorus on the algae was distinctive. Anabaena sp. strain PCC had advantages in the competition with the low nitrogen-phosphorus ra- tio and medium-low nitrogen-phosphorus ratio. Potential instability existed between anabaena sp.strain PCC and Chlorella vulgaris when the nitrogen to phosphorus ratio was medium-high and high.展开更多
To produce mouse metallothionein-1 (mMT-I ) in cyanobacterium Anabaena sp. PCC 7120, a novel Escherichia co/i-cyanobacterium shuttle fusion expression vector, pKG-MT, was constructed. Via this vector, mMT-I cDNA which...To produce mouse metallothionein-1 (mMT-I ) in cyanobacterium Anabaena sp. PCC 7120, a novel Escherichia co/i-cyanobacterium shuttle fusion expression vector, pKG-MT, was constructed. Via this vector, mMT-I cDNA which was fused with a carboxyl terminal extension of the 26 kD glutathione-S-trans-ferase (GST) containing a thrombin specific site was expressed in Anabaena under the control of tac promoter. SDS-polyacrylamid gel electrophoresis (SDS-PAGE) showed that the fusion protein GST-MT was expressed in the transgenic Anabaena sp. PCC 7120 after induction with isopropylthio-β-D-galactoside (IPTG). Glutatione-S-transferase metallothionein (GST-MT) was purified from the crude extracts by affinity chromatography on immobilized glutathione and mMT- I was obtained by digesting the fusion protein with thrombin on column and gel filtration on Sephadex G-50. SDS-PAGE demonstrated that the purified mMT- I was the desired protein. The result of ELISA for the purified mMT-I showed that the recovery of mMT- I from the transgenic cyanobacterium was about 0.6 mg/g fresh weight. According to the data of atomic absorption assay, metal-binding activity of the purified mMT-I was almost the same as that of wild type MT.展开更多
基金Supported by Ecological Environment Construction and Protection Demonstration Project of Three Gorges~~
文摘[Objective] The aim was to explore the relationship between alage-lysing bacterium and Anabaena flosaquae so as to provide reference for the control of bloom. [Method] An algae-lysing bacterium strain named S7 was isolated from eu- trophic river. The lyric efficiency and performing mode of S7 strain to Anabaena flos- aquae was studied. Influence of different environmental factors and the relationship between S7 strain and Anabaena flosaquae was also studied, and then the bacteri- um strain was physiologically identified. [Result] More than 90% of Anabaena flos- aquae had been removed by 7 d when the volume ratio of medium to algae solu- tion was 30%, the pH was 9 and the temperature was 35 ℃. These results also showed that a mutual inhibit relationship existed between S7 strain and Anabaena flos-aquae. The S7 strain killed the algae by indirectly through certain lyric agents in absence of direct contact with the target but by secreting metabolites. Moreover, these lyric agents also had the thermostability. 16SrDNA sequence analysis showed that S7 strain belonged to Chryseobacterium sp. [Conclusion] The examined Poly-p proved that S7 strain is polyphosphate accumulating bacteria （PAOs） and has better lyric efficiency.
基金Supported by Modern Agricultural Production Technological System Construction(No:CARS-49)Central Public-Interest Scientific Institution Basal Research Fund(No:2013JBFM06)Jiangsu Wuxi Agricultural Scientific Cooperation Program~~
文摘This paper studied the effects of different ratios of nitrogen and phospho- rus on the growth and competition of Anabaena sp. strain PCC and chloralla vul- gads （low nitrogen-phosphorus ratio group： N/P=16：1; Medium low nitrogen-phospho- rus ratio group： N/P=32：1; Medium high nitrogen-phosphorus ratio group： N/P=64：1; High nitrogen-phosphorus ratio group： N/P=320：1）. Results suggested that the largest amount of anabaena sp.strain PCC survived in medium high nitrogen-phosphorus ratio group. The nitrogen-phosphorus ratio showed no significant influences on the growth of Chlorella vulgaris, but it exerted dramatic influences on the growth of Chlore/la vulgaris of the mixed cultivation system. The largest amount of Ch/orel/a vulgaris can be found in the medium-high nitrogen-phosphorus ratio group. The inhi- bition parameter of nitrogen-phosphorus on the algae was distinctive. Anabaena sp. strain PCC had advantages in the competition with the low nitrogen-phosphorus ra- tio and medium-low nitrogen-phosphorus ratio. Potential instability existed between anabaena sp.strain PCC and Chlorella vulgaris when the nitrogen to phosphorus ratio was medium-high and high.
文摘To produce mouse metallothionein-1 (mMT-I ) in cyanobacterium Anabaena sp. PCC 7120, a novel Escherichia co/i-cyanobacterium shuttle fusion expression vector, pKG-MT, was constructed. Via this vector, mMT-I cDNA which was fused with a carboxyl terminal extension of the 26 kD glutathione-S-trans-ferase (GST) containing a thrombin specific site was expressed in Anabaena under the control of tac promoter. SDS-polyacrylamid gel electrophoresis (SDS-PAGE) showed that the fusion protein GST-MT was expressed in the transgenic Anabaena sp. PCC 7120 after induction with isopropylthio-β-D-galactoside (IPTG). Glutatione-S-transferase metallothionein (GST-MT) was purified from the crude extracts by affinity chromatography on immobilized glutathione and mMT- I was obtained by digesting the fusion protein with thrombin on column and gel filtration on Sephadex G-50. SDS-PAGE demonstrated that the purified mMT- I was the desired protein. The result of ELISA for the purified mMT-I showed that the recovery of mMT- I from the transgenic cyanobacterium was about 0.6 mg/g fresh weight. According to the data of atomic absorption assay, metal-binding activity of the purified mMT-I was almost the same as that of wild type MT.
