[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
Water blooms have become a worldwide environmental problem. Recently, algicidal bacteria have attracted wide attention as possible agents for inhibiting algal water blooms. In this study, one strain of algicidal bacte...Water blooms have become a worldwide environmental problem. Recently, algicidal bacteria have attracted wide attention as possible agents for inhibiting algal water blooms. In this study, one strain of algicidal bacterium B5 was isolated from activated sludge. On the basis of analysis of its physiological characteristics and 16S rDNA gene sequence, it was identified as Bacillusfusiformis. Its algaelysing characteristics on Microcystis aeruginosa, Chlorella and Scenedesmus were tested. The results showed that： （1） the algicidal bacterium B5 is a Gram-negative bacterium. The 16S rDNA nucleotide sequence homology of strain B5 with 2 strains of B. fusiformis reached 99.86%, so B5 was identified as B. fusiformis; （2） the algal-lysing effects of the algicidal bacterium B5 on M. aeruginosa, Chlorella and Scenedesrnus were pronounced. The initial bacterial and algal cell densities strongly influence the removal rates of chlorophyll-a. The greater the initial bacterial cell density, the faster the degradation of chlorophyll-a. The greater the initial algal cell density, the slower the degradation of chlorophyll-a. When the bacterial cell density was 3.6 × 10^7 cells/ml, nearly 90% of chlorophyll-a was removed. When the chlorophyll-a concentration was less than 550 μg/L, about 70% was removed; （3） the strain B5 lysed algae by secreting metabolites and these metabolites could bear heat treatment.展开更多
Algae-lysing bacteria A1 has good control effect on the moss through its extracellular secretion. In order to further study its control mechanism, the sin- gle-factor tests of temperature and pH value, the activated c...Algae-lysing bacteria A1 has good control effect on the moss through its extracellular secretion. In order to further study its control mechanism, the sin- gle-factor tests of temperature and pH value, the activated carbon adsorption test, the organic solvent extraction test and the crude extract of active substance test were carried out to explore the characteristics of active substances. The results showed that the algae-lysing active ingredient of A1 strain had strong thermal stabili- ty, which still had good algae-lysing effect after being treated at 121 ℃ ; when the pH values of fermentation liquid were adjusted to 2.0 and 4.0 respectively, the active substances lost their activities, but their control ability against moss would be enhanced under the alkaline conditions ; the active substances could not be ad- sorbed by activated carbon; the algae-lysing active substances showed strong hydrophilie ability when they were extracted by ethyl acetate, petroleum ether and chloroform. Therefore, it could be speculated that the active substances belonged to carbohydrates. The crude extract results of algae-lysing active substances showed that the active substances secreted by A1 strain were composed by a variety of algae-lysing active substances.展开更多
[Objectives]This study was conducted to explore the culture conditions for siderophore production and preliminarily investigate the growth-promoting effects of strains.[Methods]Endophytic bacteria secreting siderophor...[Objectives]This study was conducted to explore the culture conditions for siderophore production and preliminarily investigate the growth-promoting effects of strains.[Methods]Endophytic bacteria secreting siderophores were isolated and screened from the roots of the plant Saposhnikovia divaricata(Trucz.)Schischk.The siderophore-producing capability was confirmed through qualitative detection and gene cluster analysis.[Results]The screened endophytic bacterium PB-2 belonged to the genus Paenibacillus sp.and could produce catechol-type or carboxylate-type siderophores.When cultured in MKB medium with 15 g/L glycerol as the carbon source and 6 g/L glycine as the nitrogen source for 3 d,the strain exhibited efficient siderophore secretion.Appropriate concentrations of Fe^(3+),Co^(2+),Cu^(2+)and Al^(3+)promoted siderophore production,with 15μmol/L Fe^(3+)being the most effective.Under the combined influences of siderophores,volatile compounds and other factors,strain PB-2 altered the root morphology of mulberry seedlings and increased their biomass.The primary root length decreased by 9.15%,while the number and length of root hairs increased by 37.93%and 16.37%,respectively,and the total biomass increased by 10.26%,all showing significant differences(P<0.05).Additionally,strain PB-2 enhanced the activities of defense-related enzymes in mulberry seedling leaves.The activities of superoxide dismutase(SOD)and peroxidase(POD)increased significantly(P<0.05)by 247.27%and 189.47%,respectively,compared with the control group.The activities of phenylalanine ammonialyase(PAL)and polyphenol oxidase(PPO)also showed varying degrees of increase.[Conclusions]This study provided a theoretical basis for rational utilization of endophytic growth-promoting strains secreting siderophores in the sustainable development of agriculture.展开更多
Study of marine noctilucence in marine is important to fishery, environmental monitoring and military affairs. A luminous bacterial strain D2 was isolated from the marine sediment samples collected near Donghai Island...Study of marine noctilucence in marine is important to fishery, environmental monitoring and military affairs. A luminous bacterial strain D2 was isolated from the marine sediment samples collected near Donghai Island in Zhanjiang, China. The primary cultural and luminescent conditions of luminous bacterium D2 which was identified as Vibrio sp. were determined in liquid culture. The results showed that pH 7.0, 35 ℃, with 2.0 % NaCI, were the best growth conditions, and pH5 - 6, 20℃, OD600 0.08, with 3.0 % NaCI, were the optimal luminescent conditions.展开更多
[ Objective] The purpose was to screen bacterium with antagonistic effect against pathogen of spot blotch disease in pakchoi in vegetable field. [Method] More than 200 strains of bacteria which could produce spore wer...[ Objective] The purpose was to screen bacterium with antagonistic effect against pathogen of spot blotch disease in pakchoi in vegetable field. [Method] More than 200 strains of bacteria which could produce spore were isolated from soil in different places. Through screening and rescreening, the bacteria with higher antibacterial activity were conducted observation about thallus shapes and colony characters, a series of physiological and biochemical tests were performed. [Result] Rescreening results indicated that the strains including ZG-10, ZG-19, ZG-59, ZG-72 and ZG-31 had significant antibacterial activity, which had very high research value and good application prospect for biocontrol on spot blotch disease in pakchoi; the strain ZG-10 was identified to be Bacillus subtilis. [ Conclusion] The strain ZG-10 had biocontrol potential and good development prospect. This research laid certain basis for subsequent research and strated a new way for the application of antagonistic strain and proteinum polypeptide in agdculture.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Project supported by the Special Funds for Doctor's Station of University(No.20060246024)Young Fund of Fudan University,and the Shanghai Tongji Gao Tingyao Environmental Science and Technology Developmem Fundation
文摘Water blooms have become a worldwide environmental problem. Recently, algicidal bacteria have attracted wide attention as possible agents for inhibiting algal water blooms. In this study, one strain of algicidal bacterium B5 was isolated from activated sludge. On the basis of analysis of its physiological characteristics and 16S rDNA gene sequence, it was identified as Bacillusfusiformis. Its algaelysing characteristics on Microcystis aeruginosa, Chlorella and Scenedesmus were tested. The results showed that： （1） the algicidal bacterium B5 is a Gram-negative bacterium. The 16S rDNA nucleotide sequence homology of strain B5 with 2 strains of B. fusiformis reached 99.86%, so B5 was identified as B. fusiformis; （2） the algal-lysing effects of the algicidal bacterium B5 on M. aeruginosa, Chlorella and Scenedesrnus were pronounced. The initial bacterial and algal cell densities strongly influence the removal rates of chlorophyll-a. The greater the initial bacterial cell density, the faster the degradation of chlorophyll-a. The greater the initial algal cell density, the slower the degradation of chlorophyll-a. When the bacterial cell density was 3.6 × 10^7 cells/ml, nearly 90% of chlorophyll-a was removed. When the chlorophyll-a concentration was less than 550 μg/L, about 70% was removed; （3） the strain B5 lysed algae by secreting metabolites and these metabolites could bear heat treatment.
基金Supported by Scientific and Technological Research Projects in Suihua University(KQ1002004)~~
文摘Algae-lysing bacteria A1 has good control effect on the moss through its extracellular secretion. In order to further study its control mechanism, the sin- gle-factor tests of temperature and pH value, the activated carbon adsorption test, the organic solvent extraction test and the crude extract of active substance test were carried out to explore the characteristics of active substances. The results showed that the algae-lysing active ingredient of A1 strain had strong thermal stabili- ty, which still had good algae-lysing effect after being treated at 121 ℃ ; when the pH values of fermentation liquid were adjusted to 2.0 and 4.0 respectively, the active substances lost their activities, but their control ability against moss would be enhanced under the alkaline conditions ; the active substances could not be ad- sorbed by activated carbon; the algae-lysing active substances showed strong hydrophilie ability when they were extracted by ethyl acetate, petroleum ether and chloroform. Therefore, it could be speculated that the active substances belonged to carbohydrates. The crude extract results of algae-lysing active substances showed that the active substances secreted by A1 strain were composed by a variety of algae-lysing active substances.
基金Supported by Doctoral Start-up Fund of Jiangsu University of Science and Technology(1102931901).
文摘[Objectives]This study was conducted to explore the culture conditions for siderophore production and preliminarily investigate the growth-promoting effects of strains.[Methods]Endophytic bacteria secreting siderophores were isolated and screened from the roots of the plant Saposhnikovia divaricata(Trucz.)Schischk.The siderophore-producing capability was confirmed through qualitative detection and gene cluster analysis.[Results]The screened endophytic bacterium PB-2 belonged to the genus Paenibacillus sp.and could produce catechol-type or carboxylate-type siderophores.When cultured in MKB medium with 15 g/L glycerol as the carbon source and 6 g/L glycine as the nitrogen source for 3 d,the strain exhibited efficient siderophore secretion.Appropriate concentrations of Fe^(3+),Co^(2+),Cu^(2+)and Al^(3+)promoted siderophore production,with 15μmol/L Fe^(3+)being the most effective.Under the combined influences of siderophores,volatile compounds and other factors,strain PB-2 altered the root morphology of mulberry seedlings and increased their biomass.The primary root length decreased by 9.15%,while the number and length of root hairs increased by 37.93%and 16.37%,respectively,and the total biomass increased by 10.26%,all showing significant differences(P<0.05).Additionally,strain PB-2 enhanced the activities of defense-related enzymes in mulberry seedling leaves.The activities of superoxide dismutase(SOD)and peroxidase(POD)increased significantly(P<0.05)by 247.27%and 189.47%,respectively,compared with the control group.The activities of phenylalanine ammonialyase(PAL)and polyphenol oxidase(PPO)also showed varying degrees of increase.[Conclusions]This study provided a theoretical basis for rational utilization of endophytic growth-promoting strains secreting siderophores in the sustainable development of agriculture.
文摘Study of marine noctilucence in marine is important to fishery, environmental monitoring and military affairs. A luminous bacterial strain D2 was isolated from the marine sediment samples collected near Donghai Island in Zhanjiang, China. The primary cultural and luminescent conditions of luminous bacterium D2 which was identified as Vibrio sp. were determined in liquid culture. The results showed that pH 7.0, 35 ℃, with 2.0 % NaCI, were the best growth conditions, and pH5 - 6, 20℃, OD600 0.08, with 3.0 % NaCI, were the optimal luminescent conditions.
文摘[ Objective] The purpose was to screen bacterium with antagonistic effect against pathogen of spot blotch disease in pakchoi in vegetable field. [Method] More than 200 strains of bacteria which could produce spore were isolated from soil in different places. Through screening and rescreening, the bacteria with higher antibacterial activity were conducted observation about thallus shapes and colony characters, a series of physiological and biochemical tests were performed. [Result] Rescreening results indicated that the strains including ZG-10, ZG-19, ZG-59, ZG-72 and ZG-31 had significant antibacterial activity, which had very high research value and good application prospect for biocontrol on spot blotch disease in pakchoi; the strain ZG-10 was identified to be Bacillus subtilis. [ Conclusion] The strain ZG-10 had biocontrol potential and good development prospect. This research laid certain basis for subsequent research and strated a new way for the application of antagonistic strain and proteinum polypeptide in agdculture.
