The harmful algal bloom primarily caused by Microcystis aeruginosa(M.aeruginosa)has become one of the serious biological pollution issues in actual water,which has received intense attention worldwide.Over the past ye...The harmful algal bloom primarily caused by Microcystis aeruginosa(M.aeruginosa)has become one of the serious biological pollution issues in actual water,which has received intense attention worldwide.Over the past years,increasing number of publications have reported that metal-organic frameworks(MOFs)based functional materials exhibited significant inhibition against M.aeruginosa via multiple mechanisms,but no review papers systematically presented progresses regarding MOFs-based materials for M.aeruginosa control up to now.With this review paper,we summarized the state-of-the-art studies of MOFsbased materials for M.aeruginosa removal,comparing and discussing the design strategies of MOFs-based materials and their antimicrobial mechanisms.Meanwhile,we discussed methods for evaluating the water purification performances of MOFs-based materials against M.aeruginosa.Finally,the perspectives for design of novel MOFs-based functional materials and application scenarios were proposed to provide an outlook on areas where greater efforts should be made in the future.展开更多
Inactivation of cyanobacterial cells and simultaneous control of secondary metabolites is of significant necessity for the treatment of cyanobacteria-laden water.Acetylacetone(AcAc)has been reported a specific algicid...Inactivation of cyanobacterial cells and simultaneous control of secondary metabolites is of significant necessity for the treatment of cyanobacteria-laden water.Acetylacetone(AcAc)has been reported a specific algicide to inactivate Microcystis aeruginosa(M.aeruginosa)and an effective light activator to degrade pollutants.This study systematically investigated the photodegradation ability of AcAc under xenon(Xe)irradiation on the secondary metabolites of M.aeruginosa,mainly algal organic matter(AOM),especially toxic microcystin-LR(MC-LR).Results showed that AcAc outperformed H_(2)O_(2)in destructing the protein-like substances,humic acid-like matters,aromatic proteins and fulvic-like substances of AOM.For MC-LR(250μg/L),0.05 mmol/L AcAc attained the same degradation efficiency(87.0%)as 0.1mmol/L H_(2)O_(2).The degradation mechanism of Xe/AcAc might involve photo-induced energy/electron transfer and formation of carbon center radicals.Alkaline conditions(pH>9.0)were detrimental to the photoactivity of AcAc,corresponding to the observed degradation rate constant(k_(1)value)of MC-LR drastically decreasing to 0.0013 min^(-1)as solution pH exceeded 9.0.The PO_(4)^(3-)and HCO_(3)^(-)ions had obvious inhibition effects,whereas NO_(3)^(-)slightly improved k_(1)value from 0.0277 min^(-1)to 0.0321 min^(-1).The presence of AOM did not significantly inhibit MC-LR degradation in Xe/AcAc system.In addition,the biological toxicity of MC-LR was greatly reduced after photoreaction.These results demonstrated that AcAc was an alternative algicidal agent to effectively inactivate algal cells and simultaneously control the secondary metabolites after cell lysis.Nevertheless,the concentration and irradiation conditions should be further optimized in practical application.展开更多
Aeration induced turbulence was considered as an important measure to control the occurrence of cyanobacterial blooms in many lakes.Different aeration intensities were set for the culture of Microcystis aeruginosa bas...Aeration induced turbulence was considered as an important measure to control the occurrence of cyanobacterial blooms in many lakes.Different aeration intensities were set for the culture of Microcystis aeruginosa based on the formation of Microcystis colony at high iron concentrations.The turbulent dissipation rate was calculated using a computational fluid dynamics(CFD)model to evaluate the intensity of turbulence.The effects of turbulence on the formation of Microcystis colony and the release of microcystin were analyzed.Results show that turbulence produced by aeration promoted the growth of Microcystis compared to that in stagnant water.Low intensity turbulence(4×10^(-8)-1×10^(-7) m2/s3)promoted the formation of Microcystis colonies,but high intensity turbulence(1.28×10^(-6)-1.8×10^(-5) m^(2)/s^(3))did not.The increase in the number of cells per colony was slower than that in total biomass,indicating that the low intensity turbulence induced colony formation via cell division,while the high level turbulence disaggregated colonies formed by both cell division and cell adhesion.Low aeration intensity induced more production of reactive oxygen species(ROS)and malondialdehyde(MDA)in the cells of Microcystis than those in high aeration intensity.In addition,the content of microcystin(MC)-LR in the cells was positively correlated with turbulence intensity,showing that turbulence affected not only the growth and aggregation of Microcystis colonies but also their toxin production.These findings provide a better understanding of the cyanobacterial bloom formation mechanisms and help to propose feasible methods to prevent the formation of Microcystis colonies in a natural environment.展开更多
Silver carp mediated biological control techniques are often advocated for controlling cyanobacteria blooms in eutrophic water,which are often enriched with arsenic(As).How-ever,the transfer and fate of As during the ...Silver carp mediated biological control techniques are often advocated for controlling cyanobacteria blooms in eutrophic water,which are often enriched with arsenic(As).How-ever,the transfer and fate of As during the biological control of cyanobacteria blooms by silver carp in As-rich eutrophic water remain unclear.Based on the simulated ecosystem experiment,the accumulation of As in silver carp and the transfer and fate of As in the water-algae-silver carp system during Microcystis aeruginosa blooms controlled by silver carp were investigated.Microcystis aeruginosa showed high tolerance to As(V).The accumulation of As in different tissues of silver carp was different,as follows:intestine>liver>gill>skin>muscle.After silver carp ingested As-rich Microcystis aeruginosa,As accumulation in the intestine,liver,gill,and skin of silver carp was enhanced under the action of digestion and skin contact.Compared with the system without algal,As accumulation in the intestine,liver,gill,and skin of silver carp increased by 1.1,3.3,3.3,and 9.6 times,respectively,after incubation for 30 days in the system with Microcystis aeruginosa,while the accumulation of As in the muscle was only slightly increased by 0.56 mg/kg.This work revealed the transfer and fate of As during algal control by silver carp,elucidated the accumulation mechanism of As in water-algae-silver carp system,enriched our understanding of As bioaccumulation and transformation in As-rich eutrophication water,and provided a scientific basis for as-sessing and predicting As migration and enrichment in water-algae-silver carp system.展开更多
Genus Microcystis is the most common dominant species of bloom-forming cyanobacteria.Growth and colony formation are critical processes for the occurrence of Microcystis blooms.To identify allelochemicals that can inh...Genus Microcystis is the most common dominant species of bloom-forming cyanobacteria.Growth and colony formation are critical processes for the occurrence of Microcystis blooms.To identify allelochemicals that can inhibit the growth and colony formation of Microcystis,Microcystis aeruginosa was cultivated and treated with various concentrations of gramine,catechol,berberine,and sanguinarine in laboratory.Results indicate that the growth,colony formation,and extracellular polysaccharides(EPS)content of Microcystis were significantly inhibited when treated with gramine,catechol,and berberine in appropriate concentrations at high iron level(6.8 mg/L).Microcystis growth was inhibited and colony formation and EPS content were promoted when treated with sanguinarine at high iron level.These findings suggest that cyanobacterial blooms can be controlled by regulating the input of gramine,catechol,and berberine.Furthermore,this study revealed that plant allelochemicals could affect the growth and morphology of algae in aquatic ecological restoration,which may be potentially important for improving water quality.展开更多
Quaternary ammonium compounds(QACs)are commonly used in a variety of consumer and commercial products,typically as a component of disinfectants.During the COVID-19 pandemic,QACs became one of the primary agents utiliz...Quaternary ammonium compounds(QACs)are commonly used in a variety of consumer and commercial products,typically as a component of disinfectants.During the COVID-19 pandemic,QACs became one of the primary agents utilized to inactivate the SARS CoV-2 virus on surfaces.However,the ecotoxicological effects of QACs upon aquatic organisms have not been fully assessed.In this study,we examined the effects of a widely used QAC(benzalkonium chloride-C_(14),BAC-14)on two toxigenic Microcystis strains and one non-toxigenic freshwater Microcystis strain and carried out an analysis focused on primary,adaptive and compensatory stress responses at apical(growth and photosynthesis)and metabolic levels.This analysis revealed that the two toxic Microcystis strains were more tolerant than the non-toxic strain,with 96 hr-EC_(50)values of 0.70,0.76,and 0.38 mg/L BAC-14 for toxigenic M.aeruginosa FACHB-905,toxigenic M.aeruginosa FACHB-469,and non-toxigenic M.wesenbergii FACHB-908,respectively.The photosynthetic activities of the Microcystis,assessed via F_(v)/F_(m) values,were significantly suppressed under 0.4 mg/L BAC-14.Furthermore,this analysis revealed that BAC-14 altered 14,12,and 8 metabolic pathways in M.aeruginosa FACHB-905,M.aeruginosa FACHB-469,and M.wesenbergii FACHB-908,respectively.It is noteworthy that BAC-14 enhanced the level of extracellular microcystin production in the toxigenic Microcystis strains,although cell growth was not significantly affected.Collectively,these data show that BAC-14 disrupted the physiological and metabolic status of Microcystis cells and stimulated the production and release of microcystin,which could result in damage to aquatic systems.展开更多
Although many studies have found that cadmium(Cd)can be toxic to microalgae,only a few reports focused on the role of extracellular polymeric substances(EPS)in Cd(Ⅱ)detoxification.The biochemical and physiological en...Although many studies have found that cadmium(Cd)can be toxic to microalgae,only a few reports focused on the role of extracellular polymeric substances(EPS)in Cd(Ⅱ)detoxification.The biochemical and physiological endpoints of Microcystis aeruginosa,including the composition and functional groups of soluble EPS(SL-EPS),loosely bound EPS(LB-EPS),and tightly bound EPS(TB-EPS),were detected to elucidate the toxicity and detoxification mechanisms of Cd(Ⅱ)for cyanobacteria.Toxicological and physiological assays on M.aeruginosa showed that the 0.25-mg/L Cd(Ⅱ)resulted in a larger inhibition on growth and F_(v)/F_(m).Nevertheless,Cd(Ⅱ)significantly induced much higher contents of superoxide dismutase(SOD),intracellular microcystin LR(MC-LR),extracellular MC-LR,and EPS.Scanning electron microscopy with energy dispersive X-ray spectroscopy confirmed that Cd(Ⅱ)was absorbed into the EPS layer.Fourier transform infrared spectrum analysis revealed that the functional groups bound with Cd(Ⅱ)of algae biomass,SL-EPS,LB-EPS,and TB-EPS were somewhat different.The C=O/C=N groups ofδ-lactam or protein were their prominent functional groups,suggesting that amide or proteins in the EPS played a key role in the adsorption in Cd(Ⅱ).The concentration of 0.25 mg/L of Cd(Ⅱ)may change the chemical structure of EPS by altering the production of protein-like substances containing tryptophan.This study indicated that M.aeruginosa could detoxify Cd(Ⅱ)stress via induction of antioxidant capacity(higher SOD activity and MC synthesis),EPS production,and modification in chemical structure of EPS.展开更多
[Objective]The relationship between signal molecule N-acety-homoserine lactones（AHLs） and Microcystis aeruginosa cell apoptosis was studied.[Method]With M.aeruginosa as the test materials treated by 5 μmol/L N-acet...[Objective]The relationship between signal molecule N-acety-homoserine lactones（AHLs） and Microcystis aeruginosa cell apoptosis was studied.[Method]With M.aeruginosa as the test materials treated by 5 μmol/L N-acety-homoserine lactones（AHLs）,the morphology of cell apoptosis was observed through staining with DAPI.[Result]Microcystis aeruginosa cell apoptosis was induced by signal molecule N-acetyhomoserine lactones（AHLs） with the concentration of 1 μmol/L to inhibit the growth and proliferation of Microcystis aeruginosa.[Conclusion] The results provided the important scientific basis and new management ideas for the treatment of water bloom of Microcystis aeruginosa.展开更多
[Objective] The study aimed to discuss the effects of pH value on the growth metabolism of Microcystis aeruginosa and the phosphorus metabolism relationship with adnascent Pseudomonas.[Method] By the phosphorus uptake...[Objective] The study aimed to discuss the effects of pH value on the growth metabolism of Microcystis aeruginosa and the phosphorus metabolism relationship with adnascent Pseudomonas.[Method] By the phosphorus uptake experiment of M.aeruginosa under different pH conditions(8.0-10.0) and the effect experiment on the phosphorus metabolism of M.aeruginosa and adnascent Pseudomonas under different pH conditions(7.0-9.0),the phosphorus uptake of M.aeruginosa in the short time and the growth curve of M.aeruginosa,the change of phosphorus concentration in the water,the change of total phosphorus content in M.aeruginosa in the longer time were measured.[Results] In the short time,pH value had the effects on the absorption phosphorus ability of M.aeruginosa.As pH value rose,the absorption phosphorus ability enhanced.During the longer time,the higher pH value was,the quicker the growth speed of M.aeruginosa was,and the better the growth situation was.M.aeruginosa had the ability of self regulation pH value and could use the phosphorus well in the water which was released from Pseudomonas.In the system of the algae,bacteria and water,the phosphorus in the bacteria played the role of phosphorus source which was released slowly.Though the phosphorus concentration was lower,it was favorable to the growth of algae.[Conclusions] pH value was the factor that affected the circle of the phosphorus element in the system of algae-bacteria-water.展开更多
Harmful cyanobacterial blooms, especially Microcystis blooms, occur worldwide and draw widespread attention. The dynamics of microcystin-producing Microcystis and competition between microcystin-producing Microcystis ...Harmful cyanobacterial blooms, especially Microcystis blooms, occur worldwide and draw widespread attention. The dynamics of microcystin-producing Microcystis and competition between microcystin-producing Microcystis and non-microcystin-producing Microcystis are key to predicting and treating Microcystis blooms. Multiplex qPCR is a useful tool to assess such issues. In this study, we developed multiplex qPCR methods with newly-designed probes and primers for the microcystin-synthesis related genes mcyA and mcyE. We used seven toxic Microcystis strains and four non-toxic Microcystis strains to compare the differences in the ratios of toxic and non-toxic Microcystis in mixed cultures, which were calculated using abundances of the genes mcyA, mcyB, mcyD, mcy E and phycocyanin( PC). We also compared traditional cell counting and multiplex qPCR. Hierarchical clustering and principal component analysis indicated that mcyD was the most suitable mcy gene for quantification in laboratory experiments. mcyB abundances were always higher; we suggest that the amount of toxic Microcystis measured using mcyB might overestimate the actual percentages.展开更多
[Objective] The research aimed to discuss the inhibitory effect of Sophora japonica extracts against the growth of Microcystis aeruginosa.[Method] The inhibitory effect of extracted liquid of Sophora japonica leaf aga...[Objective] The research aimed to discuss the inhibitory effect of Sophora japonica extracts against the growth of Microcystis aeruginosa.[Method] The inhibitory effect of extracted liquid of Sophora japonica leaf against the growth of M.aeruginosa was measured.Moreover,the active component was studied and analyzed initially.[Result] The absolute alcohol extract of Sophora japonica leaf was separated by n-hexane,ethyl acetate,n-butanol and water phases in turn.The polar fractions were found being the majority （〉60%）.The non-polar fraction in n-nexane （about 25%） was found significantly inhibiting the growth of M.aeruginosa.The inhibition rates of fraction in n-hexane at the concentrations of 25 and 50 mg/L against M.aeruginosa in 7 d were higher than 75% and 90% respectively.In addition,chlorophyll a of M.aeruginosa was also destroyed in the presence of the hexane fraction.[Conclusion] The research provided the theoretical basis for preventing and controlling the water bloom of M.aeruginosa.展开更多
In order to monitor the changes of Microcystis along with temporal and spatial variations, seasonal variation of Microcystis in Lake Taihu was investigated by 16S-23S rRNA internal transcribed spacer denaturing gradie...In order to monitor the changes of Microcystis along with temporal and spatial variations, seasonal variation of Microcystis in Lake Taihu was investigated by 16S-23S rRNA internal transcribed spacer denaturing gradient gel electrophoresis （16S-23S rRNA-ITS DGGE） and microscopic evaluation. Samples were collected quarterly at four sites （River Mouth, Meiliang Bay, Cross Area, and Lake Center） from August 2006 to April 2007. Results showed that Microcystis dominated total phytoplankton abundance at the four sites in all seasons except winter. The average annual abundance of Microcystis was relatively high at River Mouth and Meiliang Bay, reaching 81.22×10^6 and 61.32×10^6 cells/L, respectively. For temporal variations, Shannon-Wiener diversity index （H＇） according to DGGE profile revealed the richness of Microcystis in summer （H＇ = 1.375±0.034） and winter （H＇ = 1.650 ±0.032） was lower than that in spring （H＇ = 2.078 ±0.031） and autumn （H＇ = 2.365 ±0.032） （P 〈 0.05）. While for spatial variations, the richness of Microcystis at River Mouth （H＇ = 2.015± 0.074） was higher than at other sites during four seasons （P 〈 0.01）. Very few differences of Microcystis diversity in the same season were observed among the other three sites （P 〉 0.05）. Canonical correspondence analysis （CCA） was performed to elucidate the relationships between Microcystis operational taxonomic units （OTUs） composition and the environmental factors. Results of CCA revealed that temperature was strongly positively correlated with the first axis （r = 0.963）, while TSS was negative correlated with the second axis （r = -0.716）. Phylogenetic tree based on the sequencing results of target bands on DGGE gel indicated that samples collected in summer and winter constituted two separated clusters.展开更多
Decomposition of Microcystis is accompanied by the release of phosphorus,during bacteria play an important role.A series of experiments were undertaken to evaluate the effect of bacteria on the decomposition of Microc...Decomposition of Microcystis is accompanied by the release of phosphorus,during bacteria play an important role.A series of experiments were undertaken to evaluate the effect of bacteria on the decomposition of Microcystis taken from Lake Taihu,China,a lake that is suffering from dense Microcystis blooms.The 16 experiments involved four size fractions of colonial Microcystis with or without the addition of lake sediment and Gram-negative bacterial inhibitor NAN_3.The highest decomposition rates were recorde...展开更多
Objective To isolate and characterize indigenous algicidal bacteria and their algae-lysing compounds active against Microcystis aeruginosa, strains TH1, TH2, and FACHB 905. Methods The bacteria were identified using t...Objective To isolate and characterize indigenous algicidal bacteria and their algae-lysing compounds active against Microcystis aeruginosa, strains TH1, TH2, and FACHB 905. Methods The bacteria were identified using the Biolog automated microbial identification system and 16S rDNA sequence analysis. The algae-lysing compounds were isolated and purified by silica gel column chromatography and reverse-phase high performance liquid chromatography. Their structures were confirmed by Nuclear Magnetic Resonance （NMR） and Fourier Transform infrared （FT-IR） spectroscopy. Algae-lysing activity was observed using microscopy. Results The algae-lysing bacterium LTH-2 isolated from Lake Taihu was identified as Serratia marcescens. Strain LTH-2 secreted a red pigment identified as prodigiosin （C20H25N30）, which showed strong lytic activity with algal strains M. aeruginoso TH1, TH2, and FACHB 905 in a concentration-dependent manner. The 50% inhibitory concentration （ICs0） of prodigiosin with the algal strains was 4.8 （±0.4）×10^-2 μg/mL, 8.9 （±1.1）×10^-2μg/mL, and 1.7 （±0.1）×10^-1 μg/mL in 24 h, respectively. Conclusion The bacterium LTH-2 and its pigment related to damage of cell membranes. The bacterium for regulating blooms of harmful M. aeruginosa. had strong Microcystis-lysing activity probably LTH-2 and its red pigment are potentially useful展开更多
Tega-numa （Lake Tega） is one of the eutrophic lakes in Japan. For the improvement of water quality in Lake Tega, the North- chiba Water Conveyance Channel was constructed in 2000, which transfer water from Tone Rive...Tega-numa （Lake Tega） is one of the eutrophic lakes in Japan. For the improvement of water quality in Lake Tega, the North- chiba Water Conveyance Channel was constructed in 2000, which transfer water from Tone River into the lake. After 2000, the dominant species of diatoms, mainly Cyclotella sp., have been replacing blue-green algae, mainly Microcystis aeruginosa in Lake Tega. This transition of dominant species would be due to the dilution, but the detail mechanism has not been understood yet. This study examined the relationship between phosphorus fluctuation caused by river water dilution to Lake Tega and dominance of algal species, M. aeruginosa or Cyclotella sp. based on the single-species and the mixed-species culture experiments. The single-species culture experiment showed that the half-saturation constant and uptake rate of phosphorus were one order lower and seven times higher for M. aeruginosa than those for Cyclotella sp. These findings implied that M. aeruginosa would possess a potential for the growth and survival over Cyclotella sp. in the phosphorus limited condition. The superiority of M. aeruginosa was reflected in the outcome of the mixed-species culture experiment, i.e., dominance of M. aeruginosa, even phosphorus concentration was lowered to 0.01 mg-P/L. Therefore, it could be concluded that the decrease in phosphorus concentration due to the river water dilution to Lake Tega would be interpreted as a minor factor for the transition of dominant species from M. aeruginosa to Cyclotella sp.展开更多
Interactions between bacteria and cyanobacteria have been suggested to have a potential to influence harmful algal bloom dynamics; however, little information on these interactions has been reported. In this study, th...Interactions between bacteria and cyanobacteria have been suggested to have a potential to influence harmful algal bloom dynamics; however, little information on these interactions has been reported. In this study, the bacterial communities associated with five strains of Microcystis aeruginosa, three species of other Microcystis spp., and four representative species of non-Microcystis cyanobacteria were compared. Bacterial 16S rDNA fragments were amplified and separated by denaturing gradient gel electrophoresis （DGGE） followed by DNA sequence analysis. The similarities among bacterial communities associated with these cyanobacteria were compared to the digitized DGGE profiles using the cluster analyses. The bacterial community structure of all cyanobacterial cultures differed. Cluster analysis showed that the similarity values among M. aeruginosa cultures were higher than those of other cyanobacterial cultures. Sequence analysis of DGGE fragments indicated the presence of bacteria including, Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Bacteroidetes and Actinobacteria in the cyanobacterial cultures. Members of the Sphingomonadales were the prevalent group among the Microcystis-associated bacteria. The results provided further evidence for species-specific associations between cyanoabcteria and heterotrophic bacteria, which are useful for understanding interactions between Microcystis and their associated bacteria.展开更多
Yttrium is a main kind of rare earth elements （REEs） with wide applications in modem industry and farming. Lead has been considered to be one of the most important heavy metal pollutants due to its environmental per...Yttrium is a main kind of rare earth elements （REEs） with wide applications in modem industry and farming. Lead has been considered to be one of the most important heavy metal pollutants due to its environmental persistence and tendency. In order to clarify the effects of REEs on cyanobacteria in case of suffering heavy metal pollutants, we investigated the effect of different concentrations of yttrium ion （y3＋） on the common blue-green microalgae Microcystis aeruginosa, grown under conditions of lead ion （Pb2＋） stress. Growth and physiological status were tested involving several important enzyme of antioxidant defense system （superoxide dismutase （SOD）, peroxidase （POD）, catalase （CAT）, malondiadehyde （MDA）, chlorophyll a （Chl-a）, soluble sugar and Microcystin-LR （MC-LR） in cultured experiments. Results indicated that growth ofM. aeruginosa was stimulated when treated less than 0.50 mg/L y3-and 0.20 mg/L is the optimum concentration. With the increasing content of Chl-a and activity of SOD, POD, CAT at the 12th day at relatively low concentration of y3＋ treatment （〈0.20 mg/L）, enhancement of photosynthesis and the improvement of eliminating active oxygen on M. aeruginosa were observed. On the contrast, soluble sugar content on algae reduced as the treatment of initial y3＋ concentration was in the range of 0.00-0.50 mg/L. Besides, there was a significant accumulation in both contents of MDA and MC-LR exposed from 1.00 to 5.00 mg/L y3＋, indicating that the ruin of antioxidant defense system and further aggravation to the existence of algal cell may be due to MC-LR releasing. M. aeruginosa might suffer a more positive physiological impact for exposure of relatively low y3＋ concentration against Pb2＋ stress harm, which provided a far-reaching significance on blue-green algae research.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
基金supported by National Natural Science Foundation of China(Nos.22176012,52370025)the Pyramid Talent Training Project of Beijing University of Civil Engineering and Architecture(No.JDLJ20220802)+1 种基金the Doctor Graduate Scientific Research Ability Improvement Project of Beijing University of Civil Engineering and Architecture(No.DG2023014)Guangxi Key Laboratory of Urban Water Environment。
文摘The harmful algal bloom primarily caused by Microcystis aeruginosa(M.aeruginosa)has become one of the serious biological pollution issues in actual water,which has received intense attention worldwide.Over the past years,increasing number of publications have reported that metal-organic frameworks(MOFs)based functional materials exhibited significant inhibition against M.aeruginosa via multiple mechanisms,but no review papers systematically presented progresses regarding MOFs-based materials for M.aeruginosa control up to now.With this review paper,we summarized the state-of-the-art studies of MOFsbased materials for M.aeruginosa removal,comparing and discussing the design strategies of MOFs-based materials and their antimicrobial mechanisms.Meanwhile,we discussed methods for evaluating the water purification performances of MOFs-based materials against M.aeruginosa.Finally,the perspectives for design of novel MOFs-based functional materials and application scenarios were proposed to provide an outlook on areas where greater efforts should be made in the future.
基金supported by the National Natural Science Foundation of China (No.21906085)the Natural Science Foundation of Jiangsu Province of China (No.BK20190547)the State Key Laboratory of Pollution Control and Resource Reuse Foundation (No.PCRRF21046)。
文摘Inactivation of cyanobacterial cells and simultaneous control of secondary metabolites is of significant necessity for the treatment of cyanobacteria-laden water.Acetylacetone(AcAc)has been reported a specific algicide to inactivate Microcystis aeruginosa(M.aeruginosa)and an effective light activator to degrade pollutants.This study systematically investigated the photodegradation ability of AcAc under xenon(Xe)irradiation on the secondary metabolites of M.aeruginosa,mainly algal organic matter(AOM),especially toxic microcystin-LR(MC-LR).Results showed that AcAc outperformed H_(2)O_(2)in destructing the protein-like substances,humic acid-like matters,aromatic proteins and fulvic-like substances of AOM.For MC-LR(250μg/L),0.05 mmol/L AcAc attained the same degradation efficiency(87.0%)as 0.1mmol/L H_(2)O_(2).The degradation mechanism of Xe/AcAc might involve photo-induced energy/electron transfer and formation of carbon center radicals.Alkaline conditions(pH>9.0)were detrimental to the photoactivity of AcAc,corresponding to the observed degradation rate constant(k_(1)value)of MC-LR drastically decreasing to 0.0013 min^(-1)as solution pH exceeded 9.0.The PO_(4)^(3-)and HCO_(3)^(-)ions had obvious inhibition effects,whereas NO_(3)^(-)slightly improved k_(1)value from 0.0277 min^(-1)to 0.0321 min^(-1).The presence of AOM did not significantly inhibit MC-LR degradation in Xe/AcAc system.In addition,the biological toxicity of MC-LR was greatly reduced after photoreaction.These results demonstrated that AcAc was an alternative algicidal agent to effectively inactivate algal cells and simultaneously control the secondary metabolites after cell lysis.Nevertheless,the concentration and irradiation conditions should be further optimized in practical application.
基金Supported by the National Natural Science Foundation of China(No.51979236)。
文摘Aeration induced turbulence was considered as an important measure to control the occurrence of cyanobacterial blooms in many lakes.Different aeration intensities were set for the culture of Microcystis aeruginosa based on the formation of Microcystis colony at high iron concentrations.The turbulent dissipation rate was calculated using a computational fluid dynamics(CFD)model to evaluate the intensity of turbulence.The effects of turbulence on the formation of Microcystis colony and the release of microcystin were analyzed.Results show that turbulence produced by aeration promoted the growth of Microcystis compared to that in stagnant water.Low intensity turbulence(4×10^(-8)-1×10^(-7) m2/s3)promoted the formation of Microcystis colonies,but high intensity turbulence(1.28×10^(-6)-1.8×10^(-5) m^(2)/s^(3))did not.The increase in the number of cells per colony was slower than that in total biomass,indicating that the low intensity turbulence induced colony formation via cell division,while the high level turbulence disaggregated colonies formed by both cell division and cell adhesion.Low aeration intensity induced more production of reactive oxygen species(ROS)and malondialdehyde(MDA)in the cells of Microcystis than those in high aeration intensity.In addition,the content of microcystin(MC)-LR in the cells was positively correlated with turbulence intensity,showing that turbulence affected not only the growth and aggregation of Microcystis colonies but also their toxin production.These findings provide a better understanding of the cyanobacterial bloom formation mechanisms and help to propose feasible methods to prevent the formation of Microcystis colonies in a natural environment.
基金supported by the National Natural Science Foundation of China(Nos.41572230 and 41172219)the Grant for Innovative Research Groups of the National Natural Sci-ence Foundation of China(No.41521001)+1 种基金the Special Scien-tific Research Project of Hanzhong City-Shaanxi University of Technology Co-construction State Key Laboratory(No.SXJ-2106)the Scientific Research Foundation of State Key Laboratory of Qinba Bio-Resource and Ecological Environment(No.SXC-2105).
文摘Silver carp mediated biological control techniques are often advocated for controlling cyanobacteria blooms in eutrophic water,which are often enriched with arsenic(As).How-ever,the transfer and fate of As during the biological control of cyanobacteria blooms by silver carp in As-rich eutrophic water remain unclear.Based on the simulated ecosystem experiment,the accumulation of As in silver carp and the transfer and fate of As in the water-algae-silver carp system during Microcystis aeruginosa blooms controlled by silver carp were investigated.Microcystis aeruginosa showed high tolerance to As(V).The accumulation of As in different tissues of silver carp was different,as follows:intestine>liver>gill>skin>muscle.After silver carp ingested As-rich Microcystis aeruginosa,As accumulation in the intestine,liver,gill,and skin of silver carp was enhanced under the action of digestion and skin contact.Compared with the system without algal,As accumulation in the intestine,liver,gill,and skin of silver carp increased by 1.1,3.3,3.3,and 9.6 times,respectively,after incubation for 30 days in the system with Microcystis aeruginosa,while the accumulation of As in the muscle was only slightly increased by 0.56 mg/kg.This work revealed the transfer and fate of As during algal control by silver carp,elucidated the accumulation mechanism of As in water-algae-silver carp system,enriched our understanding of As bioaccumulation and transformation in As-rich eutrophication water,and provided a scientific basis for as-sessing and predicting As migration and enrichment in water-algae-silver carp system.
基金Supported by the Chongqing Water Conservancy Bureau Project(No.5000002021BF40001)the National Natural Science Foundation of China(No.41601537)the Science and Technology Support Project of Guizhou Province,China(No.[2022]General 148)。
文摘Genus Microcystis is the most common dominant species of bloom-forming cyanobacteria.Growth and colony formation are critical processes for the occurrence of Microcystis blooms.To identify allelochemicals that can inhibit the growth and colony formation of Microcystis,Microcystis aeruginosa was cultivated and treated with various concentrations of gramine,catechol,berberine,and sanguinarine in laboratory.Results indicate that the growth,colony formation,and extracellular polysaccharides(EPS)content of Microcystis were significantly inhibited when treated with gramine,catechol,and berberine in appropriate concentrations at high iron level(6.8 mg/L).Microcystis growth was inhibited and colony formation and EPS content were promoted when treated with sanguinarine at high iron level.These findings suggest that cyanobacterial blooms can be controlled by regulating the input of gramine,catechol,and berberine.Furthermore,this study revealed that plant allelochemicals could affect the growth and morphology of algae in aquatic ecological restoration,which may be potentially important for improving water quality.
基金supported by the National Key Research and Development Program of China (Nos.2018YFD0900701 and 2019YFD0900604)the National Natural Science Foundation of China (Nos.42107150 and 32061143029)。
文摘Quaternary ammonium compounds(QACs)are commonly used in a variety of consumer and commercial products,typically as a component of disinfectants.During the COVID-19 pandemic,QACs became one of the primary agents utilized to inactivate the SARS CoV-2 virus on surfaces.However,the ecotoxicological effects of QACs upon aquatic organisms have not been fully assessed.In this study,we examined the effects of a widely used QAC(benzalkonium chloride-C_(14),BAC-14)on two toxigenic Microcystis strains and one non-toxigenic freshwater Microcystis strain and carried out an analysis focused on primary,adaptive and compensatory stress responses at apical(growth and photosynthesis)and metabolic levels.This analysis revealed that the two toxic Microcystis strains were more tolerant than the non-toxic strain,with 96 hr-EC_(50)values of 0.70,0.76,and 0.38 mg/L BAC-14 for toxigenic M.aeruginosa FACHB-905,toxigenic M.aeruginosa FACHB-469,and non-toxigenic M.wesenbergii FACHB-908,respectively.The photosynthetic activities of the Microcystis,assessed via F_(v)/F_(m) values,were significantly suppressed under 0.4 mg/L BAC-14.Furthermore,this analysis revealed that BAC-14 altered 14,12,and 8 metabolic pathways in M.aeruginosa FACHB-905,M.aeruginosa FACHB-469,and M.wesenbergii FACHB-908,respectively.It is noteworthy that BAC-14 enhanced the level of extracellular microcystin production in the toxigenic Microcystis strains,although cell growth was not significantly affected.Collectively,these data show that BAC-14 disrupted the physiological and metabolic status of Microcystis cells and stimulated the production and release of microcystin,which could result in damage to aquatic systems.
基金Supported by the National Natural Science Foundation of China(Nos.31800457,32170383)。
文摘Although many studies have found that cadmium(Cd)can be toxic to microalgae,only a few reports focused on the role of extracellular polymeric substances(EPS)in Cd(Ⅱ)detoxification.The biochemical and physiological endpoints of Microcystis aeruginosa,including the composition and functional groups of soluble EPS(SL-EPS),loosely bound EPS(LB-EPS),and tightly bound EPS(TB-EPS),were detected to elucidate the toxicity and detoxification mechanisms of Cd(Ⅱ)for cyanobacteria.Toxicological and physiological assays on M.aeruginosa showed that the 0.25-mg/L Cd(Ⅱ)resulted in a larger inhibition on growth and F_(v)/F_(m).Nevertheless,Cd(Ⅱ)significantly induced much higher contents of superoxide dismutase(SOD),intracellular microcystin LR(MC-LR),extracellular MC-LR,and EPS.Scanning electron microscopy with energy dispersive X-ray spectroscopy confirmed that Cd(Ⅱ)was absorbed into the EPS layer.Fourier transform infrared spectrum analysis revealed that the functional groups bound with Cd(Ⅱ)of algae biomass,SL-EPS,LB-EPS,and TB-EPS were somewhat different.The C=O/C=N groups ofδ-lactam or protein were their prominent functional groups,suggesting that amide or proteins in the EPS played a key role in the adsorption in Cd(Ⅱ).The concentration of 0.25 mg/L of Cd(Ⅱ)may change the chemical structure of EPS by altering the production of protein-like substances containing tryptophan.This study indicated that M.aeruginosa could detoxify Cd(Ⅱ)stress via induction of antioxidant capacity(higher SOD activity and MC synthesis),EPS production,and modification in chemical structure of EPS.
基金Supported by National Natural Science Fund(30960036)Key Schoollevel Project of Kunming University(20091016)~~
文摘[Objective]The relationship between signal molecule N-acety-homoserine lactones（AHLs） and Microcystis aeruginosa cell apoptosis was studied.[Method]With M.aeruginosa as the test materials treated by 5 μmol/L N-acety-homoserine lactones（AHLs）,the morphology of cell apoptosis was observed through staining with DAPI.[Result]Microcystis aeruginosa cell apoptosis was induced by signal molecule N-acetyhomoserine lactones（AHLs） with the concentration of 1 μmol/L to inhibit the growth and proliferation of Microcystis aeruginosa.[Conclusion] The results provided the important scientific basis and new management ideas for the treatment of water bloom of Microcystis aeruginosa.
基金Supported by"973"Project(2008CB418003)The National Natural Science Fund(30700414)
文摘[Objective] The study aimed to discuss the effects of pH value on the growth metabolism of Microcystis aeruginosa and the phosphorus metabolism relationship with adnascent Pseudomonas.[Method] By the phosphorus uptake experiment of M.aeruginosa under different pH conditions(8.0-10.0) and the effect experiment on the phosphorus metabolism of M.aeruginosa and adnascent Pseudomonas under different pH conditions(7.0-9.0),the phosphorus uptake of M.aeruginosa in the short time and the growth curve of M.aeruginosa,the change of phosphorus concentration in the water,the change of total phosphorus content in M.aeruginosa in the longer time were measured.[Results] In the short time,pH value had the effects on the absorption phosphorus ability of M.aeruginosa.As pH value rose,the absorption phosphorus ability enhanced.During the longer time,the higher pH value was,the quicker the growth speed of M.aeruginosa was,and the better the growth situation was.M.aeruginosa had the ability of self regulation pH value and could use the phosphorus well in the water which was released from Pseudomonas.In the system of the algae,bacteria and water,the phosphorus in the bacteria played the role of phosphorus source which was released slowly.Though the phosphorus concentration was lower,it was favorable to the growth of algae.[Conclusions] pH value was the factor that affected the circle of the phosphorus element in the system of algae-bacteria-water.
基金Supported by the National Natural Science Foundation of China(Nos.31370418,41561144008)the Jiangxi Water Science and Technology Fund(No.KT201602)the State Key Laboratory of Freshwater Ecology and Biotechnology(No.2016FBZ07)
文摘Harmful cyanobacterial blooms, especially Microcystis blooms, occur worldwide and draw widespread attention. The dynamics of microcystin-producing Microcystis and competition between microcystin-producing Microcystis and non-microcystin-producing Microcystis are key to predicting and treating Microcystis blooms. Multiplex qPCR is a useful tool to assess such issues. In this study, we developed multiplex qPCR methods with newly-designed probes and primers for the microcystin-synthesis related genes mcyA and mcyE. We used seven toxic Microcystis strains and four non-toxic Microcystis strains to compare the differences in the ratios of toxic and non-toxic Microcystis in mixed cultures, which were calculated using abundances of the genes mcyA, mcyB, mcyD, mcy E and phycocyanin( PC). We also compared traditional cell counting and multiplex qPCR. Hierarchical clustering and principal component analysis indicated that mcyD was the most suitable mcy gene for quantification in laboratory experiments. mcyB abundances were always higher; we suggest that the amount of toxic Microcystis measured using mcyB might overestimate the actual percentages.
基金Supported by National Natural Science Foundation of China(41076097,41006097)Science and Technology Research Key Project of ChineseMinistry of Education(211065)+3 种基金Natural Science Foundation of Jiangsu Province,China(BK2010322)Open Research of Jiangsu Key Laboratory of Environmental Material and Environmental Engineering(K090027,K090025,K090026,K090028)Graduate Science and Technology Innovation Project of Department of Education,Jiangsu Province,China(M080960)"New Century"Talent Project of Yangzhou University,China~~
文摘[Objective] The research aimed to discuss the inhibitory effect of Sophora japonica extracts against the growth of Microcystis aeruginosa.[Method] The inhibitory effect of extracted liquid of Sophora japonica leaf against the growth of M.aeruginosa was measured.Moreover,the active component was studied and analyzed initially.[Result] The absolute alcohol extract of Sophora japonica leaf was separated by n-hexane,ethyl acetate,n-butanol and water phases in turn.The polar fractions were found being the majority （〉60%）.The non-polar fraction in n-nexane （about 25%） was found significantly inhibiting the growth of M.aeruginosa.The inhibition rates of fraction in n-hexane at the concentrations of 25 and 50 mg/L against M.aeruginosa in 7 d were higher than 75% and 90% respectively.In addition,chlorophyll a of M.aeruginosa was also destroyed in the presence of the hexane fraction.[Conclusion] The research provided the theoretical basis for preventing and controlling the water bloom of M.aeruginosa.
基金supported by the State Key Fun- damental Research and Development Program (No. 2008CB418000)the National Natural Science Foundation of China (No. 40671068)the Special Program for Lake Taihu Water Pollution Governing of Jiangsu Province (No. BK2007748)
文摘In order to monitor the changes of Microcystis along with temporal and spatial variations, seasonal variation of Microcystis in Lake Taihu was investigated by 16S-23S rRNA internal transcribed spacer denaturing gradient gel electrophoresis （16S-23S rRNA-ITS DGGE） and microscopic evaluation. Samples were collected quarterly at four sites （River Mouth, Meiliang Bay, Cross Area, and Lake Center） from August 2006 to April 2007. Results showed that Microcystis dominated total phytoplankton abundance at the four sites in all seasons except winter. The average annual abundance of Microcystis was relatively high at River Mouth and Meiliang Bay, reaching 81.22×10^6 and 61.32×10^6 cells/L, respectively. For temporal variations, Shannon-Wiener diversity index （H＇） according to DGGE profile revealed the richness of Microcystis in summer （H＇ = 1.375±0.034） and winter （H＇ = 1.650 ±0.032） was lower than that in spring （H＇ = 2.078 ±0.031） and autumn （H＇ = 2.365 ±0.032） （P 〈 0.05）. While for spatial variations, the richness of Microcystis at River Mouth （H＇ = 2.015± 0.074） was higher than at other sites during four seasons （P 〈 0.01）. Very few differences of Microcystis diversity in the same season were observed among the other three sites （P 〉 0.05）. Canonical correspondence analysis （CCA） was performed to elucidate the relationships between Microcystis operational taxonomic units （OTUs） composition and the environmental factors. Results of CCA revealed that temperature was strongly positively correlated with the first axis （r = 0.963）, while TSS was negative correlated with the second axis （r = -0.716）. Phylogenetic tree based on the sequencing results of target bands on DGGE gel indicated that samples collected in summer and winter constituted two separated clusters.
文摘Decomposition of Microcystis is accompanied by the release of phosphorus,during bacteria play an important role.A series of experiments were undertaken to evaluate the effect of bacteria on the decomposition of Microcystis taken from Lake Taihu,China,a lake that is suffering from dense Microcystis blooms.The 16 experiments involved four size fractions of colonial Microcystis with or without the addition of lake sediment and Gram-negative bacterial inhibitor NAN_3.The highest decomposition rates were recorde...
基金supported by the National Science and Technology Major Project (2012ZX07101-005)the National Natural Science Foundation of China (30972440)Jiangsu Province Postgraduate Innovation Project (CX10B-087Z)
文摘Objective To isolate and characterize indigenous algicidal bacteria and their algae-lysing compounds active against Microcystis aeruginosa, strains TH1, TH2, and FACHB 905. Methods The bacteria were identified using the Biolog automated microbial identification system and 16S rDNA sequence analysis. The algae-lysing compounds were isolated and purified by silica gel column chromatography and reverse-phase high performance liquid chromatography. Their structures were confirmed by Nuclear Magnetic Resonance （NMR） and Fourier Transform infrared （FT-IR） spectroscopy. Algae-lysing activity was observed using microscopy. Results The algae-lysing bacterium LTH-2 isolated from Lake Taihu was identified as Serratia marcescens. Strain LTH-2 secreted a red pigment identified as prodigiosin （C20H25N30）, which showed strong lytic activity with algal strains M. aeruginoso TH1, TH2, and FACHB 905 in a concentration-dependent manner. The 50% inhibitory concentration （ICs0） of prodigiosin with the algal strains was 4.8 （±0.4）×10^-2 μg/mL, 8.9 （±1.1）×10^-2μg/mL, and 1.7 （±0.1）×10^-1 μg/mL in 24 h, respectively. Conclusion The bacterium LTH-2 and its pigment related to damage of cell membranes. The bacterium for regulating blooms of harmful M. aeruginosa. had strong Microcystis-lysing activity probably LTH-2 and its red pigment are potentially useful
文摘Tega-numa （Lake Tega） is one of the eutrophic lakes in Japan. For the improvement of water quality in Lake Tega, the North- chiba Water Conveyance Channel was constructed in 2000, which transfer water from Tone River into the lake. After 2000, the dominant species of diatoms, mainly Cyclotella sp., have been replacing blue-green algae, mainly Microcystis aeruginosa in Lake Tega. This transition of dominant species would be due to the dilution, but the detail mechanism has not been understood yet. This study examined the relationship between phosphorus fluctuation caused by river water dilution to Lake Tega and dominance of algal species, M. aeruginosa or Cyclotella sp. based on the single-species and the mixed-species culture experiments. The single-species culture experiment showed that the half-saturation constant and uptake rate of phosphorus were one order lower and seven times higher for M. aeruginosa than those for Cyclotella sp. These findings implied that M. aeruginosa would possess a potential for the growth and survival over Cyclotella sp. in the phosphorus limited condition. The superiority of M. aeruginosa was reflected in the outcome of the mixed-species culture experiment, i.e., dominance of M. aeruginosa, even phosphorus concentration was lowered to 0.01 mg-P/L. Therefore, it could be concluded that the decrease in phosphorus concentration due to the river water dilution to Lake Tega would be interpreted as a minor factor for the transition of dominant species from M. aeruginosa to Cyclotella sp.
基金supported by the National Basic Research Program (973) of China (No. 2008CB418004)the Natural Science Foundation of Jiangsu Province (No.BK2007150)the China Postdoctoral Science Foundation (No. 20070410345)
文摘Interactions between bacteria and cyanobacteria have been suggested to have a potential to influence harmful algal bloom dynamics; however, little information on these interactions has been reported. In this study, the bacterial communities associated with five strains of Microcystis aeruginosa, three species of other Microcystis spp., and four representative species of non-Microcystis cyanobacteria were compared. Bacterial 16S rDNA fragments were amplified and separated by denaturing gradient gel electrophoresis （DGGE） followed by DNA sequence analysis. The similarities among bacterial communities associated with these cyanobacteria were compared to the digitized DGGE profiles using the cluster analyses. The bacterial community structure of all cyanobacterial cultures differed. Cluster analysis showed that the similarity values among M. aeruginosa cultures were higher than those of other cyanobacterial cultures. Sequence analysis of DGGE fragments indicated the presence of bacteria including, Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Bacteroidetes and Actinobacteria in the cyanobacterial cultures. Members of the Sphingomonadales were the prevalent group among the Microcystis-associated bacteria. The results provided further evidence for species-specific associations between cyanoabcteria and heterotrophic bacteria, which are useful for understanding interactions between Microcystis and their associated bacteria.
文摘Yttrium is a main kind of rare earth elements （REEs） with wide applications in modem industry and farming. Lead has been considered to be one of the most important heavy metal pollutants due to its environmental persistence and tendency. In order to clarify the effects of REEs on cyanobacteria in case of suffering heavy metal pollutants, we investigated the effect of different concentrations of yttrium ion （y3＋） on the common blue-green microalgae Microcystis aeruginosa, grown under conditions of lead ion （Pb2＋） stress. Growth and physiological status were tested involving several important enzyme of antioxidant defense system （superoxide dismutase （SOD）, peroxidase （POD）, catalase （CAT）, malondiadehyde （MDA）, chlorophyll a （Chl-a）, soluble sugar and Microcystin-LR （MC-LR） in cultured experiments. Results indicated that growth ofM. aeruginosa was stimulated when treated less than 0.50 mg/L y3-and 0.20 mg/L is the optimum concentration. With the increasing content of Chl-a and activity of SOD, POD, CAT at the 12th day at relatively low concentration of y3＋ treatment （〈0.20 mg/L）, enhancement of photosynthesis and the improvement of eliminating active oxygen on M. aeruginosa were observed. On the contrast, soluble sugar content on algae reduced as the treatment of initial y3＋ concentration was in the range of 0.00-0.50 mg/L. Besides, there was a significant accumulation in both contents of MDA and MC-LR exposed from 1.00 to 5.00 mg/L y3＋, indicating that the ruin of antioxidant defense system and further aggravation to the existence of algal cell may be due to MC-LR releasing. M. aeruginosa might suffer a more positive physiological impact for exposure of relatively low y3＋ concentration against Pb2＋ stress harm, which provided a far-reaching significance on blue-green algae research.
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.
