[Objective] The aim was to study the antialgal activities of allelochemical extracts from three terrestrial plant species.[Method] The allelochemicals were extracted from the leaves of Magnolia grandiflora,Sophora jap...[Objective] The aim was to study the antialgal activities of allelochemical extracts from three terrestrial plant species.[Method] The allelochemicals were extracted from the leaves of Magnolia grandiflora,Sophora japonica f.pendula and Buxus sinica （Rehd.et Wils.） Cheng by alcohol extraction,n-hexane,ethyl acetate and n-utanol phase.Furthermore antialgal activities of all components were determined.[Result] The active substances of M.grandiflora mainly existed in n-hexane and n-butanol phases.The active substances of S.japonica mainly existed in n-hexane phase,while the active substances of B.sinica mainly existed in ethyl acetate and aqueous phase.All the active substances showed significant antialgal activity （50% inhibition） after culture for 1 d except aqueous phase of B.sinica.In addition,inhibition rates of the tested phases increased with the increasing of culture duration and testing concentrations.The inhibition rates were over 90% against the growth of M.aeruginosa after culture for 7 d.The n-hexane and n-butanol phases of M.grandiflora exhibited the best antialgal activity,over 96% inhibition rate at the concentration of 25 μg/ml,which was significantly higher than those of the other components,furthermore it could cause shrinkage and obvious surface inanition of Microcystis aeruginosa.[Conclusion] The n-hexane and n-butanol phases of M.grandiflora have the best inhibition activities on the growth of Microcystis aeruginosa,so they are worthy of further study.展开更多
The MaMV-DC cyanophage,which infects the bloom-forming cyanobacterium Microcystis aeruginosa,was isolated from Lake Dianchi,Kunming,China.Twenty-one cyanobacterial strains were used to detect the host range of MaMV-DC...The MaMV-DC cyanophage,which infects the bloom-forming cyanobacterium Microcystis aeruginosa,was isolated from Lake Dianchi,Kunming,China.Twenty-one cyanobacterial strains were used to detect the host range of MaMV-DC.Microcystic aeruginosa FACHB-524 and plaque purification were used to isolate individual cyanophages,and culturing MaMV-DC with cyanobacteria allowed us to prepare purified cyanophages for further analysis.Electron microscopy demonstrated that the negatively stained viral particles are tadpole-shaped with an icosahedral head approximately 70 nm in diameter and a contractile tail approximately 160 nm in length.Using one-step growth experiments,the latent period and burst size of MaMV-DC were estimated to be 24–48 hours and approximately 80infectious units per cell,respectively.Restriction endonuclease digestion and agarose gel electrophoresis were performed using purified MaMV-DC genomic DNA,and the genome size was estimated to be approximately 160 kb.Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE)analysis revealed four major structural proteins.These results support the growing interest in using freshwater cyanophages to control bloom-forming cyanobacterium.展开更多
Cyanobacterial blooms in eutrophic freshwater systems are a worldwide problem, creating adverse effects for many aquatic organisms by producing toxic mierocystins and deteriorating water quality. In this study, microc...Cyanobacterial blooms in eutrophic freshwater systems are a worldwide problem, creating adverse effects for many aquatic organisms by producing toxic mierocystins and deteriorating water quality. In this study, microcystins （MCs） in Microcystis aeruginosa, and Daphnia magna exposed to M. aeruginosa, were analyzed by HPLC-MS, and the effects of M. aeruginosa on D. magna were investigated. When D. magna was exposed to M. aeruginosa for more than 2 h, Microcystin-LR （MC-LR） was detected. When exposed to 1.5× 10^6, 3× 10^6, 0.75× 10^7, and 1.5× 10^7 cell/mL of M. aeruginosa for 96 h, average survival of D. magna for treatments were 23.33%, 33.33%, 13.33%, 16.67%, respectively, which were significantly lower than the average 100% survival in the control group （P 〈 0.05）. The adverse effects ofM. aeruginosa on body length, time for the first brood, brood numbers, gross fecundity, lifespan, and population growth olD. magna were density-dependent. These results suggest that the occurrence of M. aeruginosa blooms could strongly inhibit the population growth of D. magna through depression of survival, individual growth and gross fecundity. In the most serious situations, M. aeruginosa blooms could undermine the food web by eliminating filter-feeding zooplankton, which would destroy the ecological balance of aquaculture water bodies.展开更多
基金Supported by National Natural Science Foundation of China(30671240, 30871588)~~
文摘[Objective] The aim was to study the antialgal activities of allelochemical extracts from three terrestrial plant species.[Method] The allelochemicals were extracted from the leaves of Magnolia grandiflora,Sophora japonica f.pendula and Buxus sinica （Rehd.et Wils.） Cheng by alcohol extraction,n-hexane,ethyl acetate and n-utanol phase.Furthermore antialgal activities of all components were determined.[Result] The active substances of M.grandiflora mainly existed in n-hexane and n-butanol phases.The active substances of S.japonica mainly existed in n-hexane phase,while the active substances of B.sinica mainly existed in ethyl acetate and aqueous phase.All the active substances showed significant antialgal activity （50% inhibition） after culture for 1 d except aqueous phase of B.sinica.In addition,inhibition rates of the tested phases increased with the increasing of culture duration and testing concentrations.The inhibition rates were over 90% against the growth of M.aeruginosa after culture for 7 d.The n-hexane and n-butanol phases of M.grandiflora exhibited the best antialgal activity,over 96% inhibition rate at the concentration of 25 μg/ml,which was significantly higher than those of the other components,furthermore it could cause shrinkage and obvious surface inanition of Microcystis aeruginosa.[Conclusion] The n-hexane and n-butanol phases of M.grandiflora have the best inhibition activities on the growth of Microcystis aeruginosa,so they are worthy of further study.
基金National Natural Science Foundation of China(grant nos.31072239,31270213)Knowledge Innovation Program of the Chinese Academy of Sciences(grant no.KSCX2-EW-Z-3)StateKey Laboratory of Freshwater Ecology&Biotechnology Program(grant no.2011FBZ12)
文摘The MaMV-DC cyanophage,which infects the bloom-forming cyanobacterium Microcystis aeruginosa,was isolated from Lake Dianchi,Kunming,China.Twenty-one cyanobacterial strains were used to detect the host range of MaMV-DC.Microcystic aeruginosa FACHB-524 and plaque purification were used to isolate individual cyanophages,and culturing MaMV-DC with cyanobacteria allowed us to prepare purified cyanophages for further analysis.Electron microscopy demonstrated that the negatively stained viral particles are tadpole-shaped with an icosahedral head approximately 70 nm in diameter and a contractile tail approximately 160 nm in length.Using one-step growth experiments,the latent period and burst size of MaMV-DC were estimated to be 24–48 hours and approximately 80infectious units per cell,respectively.Restriction endonuclease digestion and agarose gel electrophoresis were performed using purified MaMV-DC genomic DNA,and the genome size was estimated to be approximately 160 kb.Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE)analysis revealed four major structural proteins.These results support the growing interest in using freshwater cyanophages to control bloom-forming cyanobacterium.
基金Supported by the Aquaculture and Fisheries Collaborative Research Support Program of USAID (No. 1366)the Shanghai Rising-Star Program (No. 08QA1405900)+1 种基金the Innovation Program of Shanghai Municipal Education Commission (No. 09YZ277)the Shanghai Leading Academic Discipline Project (No. Y1101)
文摘Cyanobacterial blooms in eutrophic freshwater systems are a worldwide problem, creating adverse effects for many aquatic organisms by producing toxic mierocystins and deteriorating water quality. In this study, microcystins （MCs） in Microcystis aeruginosa, and Daphnia magna exposed to M. aeruginosa, were analyzed by HPLC-MS, and the effects of M. aeruginosa on D. magna were investigated. When D. magna was exposed to M. aeruginosa for more than 2 h, Microcystin-LR （MC-LR） was detected. When exposed to 1.5× 10^6, 3× 10^6, 0.75× 10^7, and 1.5× 10^7 cell/mL of M. aeruginosa for 96 h, average survival of D. magna for treatments were 23.33%, 33.33%, 13.33%, 16.67%, respectively, which were significantly lower than the average 100% survival in the control group （P 〈 0.05）. The adverse effects ofM. aeruginosa on body length, time for the first brood, brood numbers, gross fecundity, lifespan, and population growth olD. magna were density-dependent. These results suggest that the occurrence of M. aeruginosa blooms could strongly inhibit the population growth of D. magna through depression of survival, individual growth and gross fecundity. In the most serious situations, M. aeruginosa blooms could undermine the food web by eliminating filter-feeding zooplankton, which would destroy the ecological balance of aquaculture water bodies.
