The application of photocatalytic technology in algae killing is limited by the non-floatability and difficulty in recycling of the photocatalysts.Loading photocatalyst on magnetic or floatable carriers is the most po...The application of photocatalytic technology in algae killing is limited by the non-floatability and difficulty in recycling of the photocatalysts.Loading photocatalyst on magnetic or floatable carriers is the most popular method for overcoming the above inadequacies.In this work,a CdZnS/TiO_(2) membrane photocatalyst with adjustable suspended depth(include floating)and flexible assembly is designed,which is less prone to dislodgement due to in situ synthesis and has a wider range of applicability than previously reported photocatalysts.The photocatalytic removal of Microcystis aeruginosa revealed that the suspended depth and distribution format of the CdZnS/TiO_(2) membrane photocatalysts have striking effects on the photocatalytic removal performance of Microcystis aeruginosa,the photocatalytic removal efficiency of CdZnS/TiO_(2)-2 membrane photocatalysts for Microcystis aeruginosa could reach to 98.6%in 60 min when the photocatalysts assembled in the form of 3×3 arrays suspended at a depth of 2 cm from the liquid surface.A tiny amount of TiO_(2) loading allows the formation of Z-Scheme heterojunction,resulting in accelerating the separation efficiency of photogenerated carriers,preserving the photogenerated electrons and holes with stronger reduction and oxidation ability and inhabiting the photo-corrosion of CdZnS.展开更多
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
[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
To investigate the effect of neodymium （Nd） on Microcystis aeruginosa, the growth and physiological changes were studied by lab cultured experiments. The results showed that the content of chlorophyll a （Chl-a）, s...To investigate the effect of neodymium （Nd） on Microcystis aeruginosa, the growth and physiological changes were studied by lab cultured experiments. The results showed that the content of chlorophyll a （Chl-a）, soluble protein and the activity of superoxide dismutase （SOD）, peroxidase （POD）, and catalase （CAT） increased compared with the control （Nd3＋-free）, and the growth of M. aeruginosa was stimulated in the treatments of initial Nd3＋ concentration ≤1 mg/L; while the treatments of initial Nd3＋ concentration was in the range of 5.00–10.00 mg/L, the content of malondiadehyde （MDA） increased immediately but the activity of CAT reduced, which resulted in weakened M. aeruginosa’s ability to eliminate the active oxygen and the ruin of antioxidant defense system, and stunting the growth of M. aeruginosa. With the initial Nd3＋ concentration of 50 mg/L, the growth of M. aeruginosa was totally stunted. The ultrastructure showed that excess Nd3＋ could lead to the decrease of thylakoid and the increase of fat particle in cells of M. aeruginosa, and the cell membrane became rough and even broken, causing an irreversible damage to algal cells.展开更多
Growth and uptake of exogenous phosphate by Microcystis aeruginosa in batch culture under different temperature, photoperiod, and turbulence were studied by the method of phosphate isotope tracer. Relatively high temp...Growth and uptake of exogenous phosphate by Microcystis aeruginosa in batch culture under different temperature, photoperiod, and turbulence were studied by the method of phosphate isotope tracer. Relatively high temperature, long photoperiod and strong turbulence increased the cell density of M. aeruginosa in these batch cultures. The initial rapid uptake of phosphate by M. aeruginosa was independent of the temperature, photoperiod, and turbulence. Similarly, maximum exogenous phosphate uptake was not related to these environmental factors. However, elevated temperature and turbulence shortened the time, required to obtain maximum P accumulation. The growth of M. aeruginosa could alleviate the phosphorous leakage. Total amounts of exogenous phosphate uptake to M. aeruginosa and the phosphorus leakage of M. aeruginosa were significantly influenced by the growth state of M. aeruginosa closely correlated with the environmental factors. The maximum volume of exogenous phosphate uptake to M. aeruginosa was 46% of added exogenous phosphate in water with 16 hours of photoperiod. Thus, total amounts of exogenous phosphate uptake to M. aeruginosa were more strongly affected by the photoperiod length than temperature and turbulence.展开更多
Production and characteristics of typical taste and odor （T＆O） compounds by Microcystis aeruginosa were investigated. A few terpenoid chemicals, including 2-MIB, β-cyclocitral, and β-ionone, and a few sulfur comp...Production and characteristics of typical taste and odor （T＆O） compounds by Microcystis aeruginosa were investigated. A few terpenoid chemicals, including 2-MIB, β-cyclocitral, and β-ionone, and a few sulfur compounds, such as dimethyl sulfide and dimethyl trisulfide, were detected. β-Cyclocitral and β-carotene concentrations were observed to be relevant to the growth phases of Microcystis. During the stable growth phase, 41-865 fg/cell of β-cyclocitral were found in the laboratory culture. β-Cyclocitral concentrations correlated closely with β-carotene concentrations, with the correlation coefficient R2 = 0.96, as it is formed from the cleavage reaction of β-carotene. For dead cell cases, a high concentration of dimethyl trisulfide was detected at 3.48-6.37 fg/cell. Four T＆O compounds, including β-cyclocitral, β-ionone, heptanal and dimethyl trisulfide, were tested and found to be able to inhibit and damage Microcystis cells to varying degrees. Among these chemicals, β-cyclocitral has the strongest ability to quickly rupture cells.展开更多
Cyanobacteria, specifically Microcystis, usually form massive blooms in eutrophic freshwater lakes. Cyanobacterial samples were collected from eight sites of both Lake Taihu and Lake Chaohu in late summer to determine...Cyanobacteria, specifically Microcystis, usually form massive blooms in eutrophic freshwater lakes. Cyanobacterial samples were collected from eight sites of both Lake Taihu and Lake Chaohu in late summer to determine the diversity and distribution pattern of cyanobacteria and Microcystis in large, shallow, entropic lakes with significant spatial heterogeneity and long-term Microcystis bloom. Molecular methods based on denaturing gradient gel electrophoresis and clone library analysis were used. A similar heterogeneous distribution pattern of cyanobacteria in both lakes was observed. Most parts of these two lakes with high trophic level were dominated by Microcystis. However, in the regions with low trophic levels as well as low concentrations of chlorophyll a, Synechococcus occupied a considerable percentage. Different morphospecies and genotypes dominated the bloom-forming Microcystis populations in these two lakes. Microcystis viridis and Microcystis novacekii were dominant in Lake Chaohu, whereas Microcystis flos-aquae was dominant in Lake Taihu. Only 2 of thel3 Microcystis operational taxonomic units were shared between these two lakes. Analysis of molecular variance based on 16S to 23S internal transcribed spacer sequences indicated the significant genetic differentiation of Microcystis between these two lakes （Fst = 0.19, p 〈 0.001）. However, only 19.46% of the genetic variability was explained by the population variation between lakes, whereas most （80.54%） of the genetic variability occurred within the lakes. Phylogenetic analysis revealed no phylogeographic structure of Microcystis population in these two lakes, as illustrated by their cosmopolitan nature. Our results revealed that spatial heterogeneity within lakes has more impact on the cyanobacterial diversity than geographical isolation in a local scale.展开更多
A quantitative protocol for the rapid analysis of Microcystis cells and colonies in lake sediment was developed using a modified flow cytometer, the CytoSense. For cell enumeration, diluted sediment samples containing...A quantitative protocol for the rapid analysis of Microcystis cells and colonies in lake sediment was developed using a modified flow cytometer, the CytoSense. For cell enumeration, diluted sediment samples containing Microcystis were processed with sonication to disintegrate colonies into single cells. An optimized procedure suggested that 5 mg dw （dry weight）/mL dilution combined with 200 W x 2 min sonication yielded the highest counting efficiency. Under the optimized determination conditions, the quantification limit of this protocol was 3.3x104 cells/g dw. For colony analysis, Microcystis were isolated from the sediment by filtration. Colony lengths measured by flow cytometry were similar to those measured by microscopy for the size range of one single cell to almost 400 ~tm in length. Moreover, the relationship between colony size and cell number was determined for three Microcystis species, including Microcystisflos-aquae, M. aeruginosa and M. wessenbergii. Regression formulas were used to calculate the cell numbers in different- sized colonies. The developed protocol was applied to field sediment samples from Lake Taihu. The results indicated the potential and applicability of flow cytometry as a tool for the rapid analysis of benthic Microcystis. This study provided a new capability for the high frequency monitoring of benthic overwintering and population dynamics of this bloom-forming cyanobacterium.展开更多
基金financially supported by the Natural Science Foundation of ShanDong(Nos.ZR2023QD152 and ZR2021MD002).
文摘The application of photocatalytic technology in algae killing is limited by the non-floatability and difficulty in recycling of the photocatalysts.Loading photocatalyst on magnetic or floatable carriers is the most popular method for overcoming the above inadequacies.In this work,a CdZnS/TiO_(2) membrane photocatalyst with adjustable suspended depth(include floating)and flexible assembly is designed,which is less prone to dislodgement due to in situ synthesis and has a wider range of applicability than previously reported photocatalysts.The photocatalytic removal of Microcystis aeruginosa revealed that the suspended depth and distribution format of the CdZnS/TiO_(2) membrane photocatalysts have striking effects on the photocatalytic removal performance of Microcystis aeruginosa,the photocatalytic removal efficiency of CdZnS/TiO_(2)-2 membrane photocatalysts for Microcystis aeruginosa could reach to 98.6%in 60 min when the photocatalysts assembled in the form of 3×3 arrays suspended at a depth of 2 cm from the liquid surface.A tiny amount of TiO_(2) loading allows the formation of Z-Scheme heterojunction,resulting in accelerating the separation efficiency of photogenerated carriers,preserving the photogenerated electrons and holes with stronger reduction and oxidation ability and inhabiting the photo-corrosion of CdZnS.
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 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.
基金supported by Educational Commission of Sichuan Province of China (10ZA059)Innovation Programme of College Students of China (01409207)
文摘To investigate the effect of neodymium （Nd） on Microcystis aeruginosa, the growth and physiological changes were studied by lab cultured experiments. The results showed that the content of chlorophyll a （Chl-a）, soluble protein and the activity of superoxide dismutase （SOD）, peroxidase （POD）, and catalase （CAT） increased compared with the control （Nd3＋-free）, and the growth of M. aeruginosa was stimulated in the treatments of initial Nd3＋ concentration ≤1 mg/L; while the treatments of initial Nd3＋ concentration was in the range of 5.00–10.00 mg/L, the content of malondiadehyde （MDA） increased immediately but the activity of CAT reduced, which resulted in weakened M. aeruginosa’s ability to eliminate the active oxygen and the ruin of antioxidant defense system, and stunting the growth of M. aeruginosa. With the initial Nd3＋ concentration of 50 mg/L, the growth of M. aeruginosa was totally stunted. The ultrastructure showed that excess Nd3＋ could lead to the decrease of thylakoid and the increase of fat particle in cells of M. aeruginosa, and the cell membrane became rough and even broken, causing an irreversible damage to algal cells.
文摘Growth and uptake of exogenous phosphate by Microcystis aeruginosa in batch culture under different temperature, photoperiod, and turbulence were studied by the method of phosphate isotope tracer. Relatively high temperature, long photoperiod and strong turbulence increased the cell density of M. aeruginosa in these batch cultures. The initial rapid uptake of phosphate by M. aeruginosa was independent of the temperature, photoperiod, and turbulence. Similarly, maximum exogenous phosphate uptake was not related to these environmental factors. However, elevated temperature and turbulence shortened the time, required to obtain maximum P accumulation. The growth of M. aeruginosa could alleviate the phosphorous leakage. Total amounts of exogenous phosphate uptake to M. aeruginosa and the phosphorus leakage of M. aeruginosa were significantly influenced by the growth state of M. aeruginosa closely correlated with the environmental factors. The maximum volume of exogenous phosphate uptake to M. aeruginosa was 46% of added exogenous phosphate in water with 16 hours of photoperiod. Thus, total amounts of exogenous phosphate uptake to M. aeruginosa were more strongly affected by the photoperiod length than temperature and turbulence.
基金supported by the National Natural Science Foundation of China (No.51208456)the Foundation of Key Laboratory of Yangtze River Water Environment, Ministry of Education (Tongji University), China (No.YRWEF201302)+1 种基金the National Major Science and Technology Project of China (No.2008ZX07421-002)the Taiwan National Science Council Project (No.NSC101-2221-E-006-152-MY3)
文摘Production and characteristics of typical taste and odor （T＆O） compounds by Microcystis aeruginosa were investigated. A few terpenoid chemicals, including 2-MIB, β-cyclocitral, and β-ionone, and a few sulfur compounds, such as dimethyl sulfide and dimethyl trisulfide, were detected. β-Cyclocitral and β-carotene concentrations were observed to be relevant to the growth phases of Microcystis. During the stable growth phase, 41-865 fg/cell of β-cyclocitral were found in the laboratory culture. β-Cyclocitral concentrations correlated closely with β-carotene concentrations, with the correlation coefficient R2 = 0.96, as it is formed from the cleavage reaction of β-carotene. For dead cell cases, a high concentration of dimethyl trisulfide was detected at 3.48-6.37 fg/cell. Four T＆O compounds, including β-cyclocitral, β-ionone, heptanal and dimethyl trisulfide, were tested and found to be able to inhibit and damage Microcystis cells to varying degrees. Among these chemicals, β-cyclocitral has the strongest ability to quickly rupture cells.
基金supported by the National Major Scienceand Technology Program for Water Pollution Controland Treatment (No. 2008ZX07103-005)the National Basic Research Program (973) of China (No.2008CB418000)
文摘Cyanobacteria, specifically Microcystis, usually form massive blooms in eutrophic freshwater lakes. Cyanobacterial samples were collected from eight sites of both Lake Taihu and Lake Chaohu in late summer to determine the diversity and distribution pattern of cyanobacteria and Microcystis in large, shallow, entropic lakes with significant spatial heterogeneity and long-term Microcystis bloom. Molecular methods based on denaturing gradient gel electrophoresis and clone library analysis were used. A similar heterogeneous distribution pattern of cyanobacteria in both lakes was observed. Most parts of these two lakes with high trophic level were dominated by Microcystis. However, in the regions with low trophic levels as well as low concentrations of chlorophyll a, Synechococcus occupied a considerable percentage. Different morphospecies and genotypes dominated the bloom-forming Microcystis populations in these two lakes. Microcystis viridis and Microcystis novacekii were dominant in Lake Chaohu, whereas Microcystis flos-aquae was dominant in Lake Taihu. Only 2 of thel3 Microcystis operational taxonomic units were shared between these two lakes. Analysis of molecular variance based on 16S to 23S internal transcribed spacer sequences indicated the significant genetic differentiation of Microcystis between these two lakes （Fst = 0.19, p 〈 0.001）. However, only 19.46% of the genetic variability was explained by the population variation between lakes, whereas most （80.54%） of the genetic variability occurred within the lakes. Phylogenetic analysis revealed no phylogeographic structure of Microcystis population in these two lakes, as illustrated by their cosmopolitan nature. Our results revealed that spatial heterogeneity within lakes has more impact on the cyanobacterial diversity than geographical isolation in a local scale.
基金supported by the National Basic Research Program (973) of China (No. 2008CB418006)the National Special Program of Water Environment (No.2009ZX07106-001-002)+1 种基金the National Natural Science Foundation of China (No. 31070355)the National Major Science and Technology Program for Water Pollution Control and Treatment (No. 2009ZX07101-013)
文摘A quantitative protocol for the rapid analysis of Microcystis cells and colonies in lake sediment was developed using a modified flow cytometer, the CytoSense. For cell enumeration, diluted sediment samples containing Microcystis were processed with sonication to disintegrate colonies into single cells. An optimized procedure suggested that 5 mg dw （dry weight）/mL dilution combined with 200 W x 2 min sonication yielded the highest counting efficiency. Under the optimized determination conditions, the quantification limit of this protocol was 3.3x104 cells/g dw. For colony analysis, Microcystis were isolated from the sediment by filtration. Colony lengths measured by flow cytometry were similar to those measured by microscopy for the size range of one single cell to almost 400 ~tm in length. Moreover, the relationship between colony size and cell number was determined for three Microcystis species, including Microcystisflos-aquae, M. aeruginosa and M. wessenbergii. Regression formulas were used to calculate the cell numbers in different- sized colonies. The developed protocol was applied to field sediment samples from Lake Taihu. The results indicated the potential and applicability of flow cytometry as a tool for the rapid analysis of benthic Microcystis. This study provided a new capability for the high frequency monitoring of benthic overwintering and population dynamics of this bloom-forming cyanobacterium.
