Seven types of microcystins,isolated from Microcystis waterbloom in Lake Dalai,were characterized.The major toxins:MCYST-LR,MCYST-RR,[D-Asp<sup>3</sup>]MCYST-LR and[Dha<sup>7</sup>]MCYST-LR wer...Seven types of microcystins,isolated from Microcystis waterbloom in Lake Dalai,were characterized.The major toxins:MCYST-LR,MCYST-RR,[D-Asp<sup>3</sup>]MCYST-LR and[Dha<sup>7</sup>]MCYST-LR were identified by high performance liquid chromatography（HPLC）,as com-pared with the authentic microcystins.The minor toxins:MCYST FR,[L-Mser<sup>7</sup>]MCYST-LRand an unknown MCYST which was most likely to be MCYST-（H<sub>4</sub>）YR were identified with frit-fast atom bombardment liquid chromatography/mass spectrometry（Frit-FAB LC/MS）and aminoacid analysis.The toxigenic diversity in blue-green algae（cyanobacteria）was discussed.展开更多
To explore how decomposed Microcystis-dominant cyanobacterial blooms affect submerged macrophytes,the submerged plant Myriophyllum spicatum was exposed to cell extracts from microcystin(MC)-and non-MC-producing Microc...To explore how decomposed Microcystis-dominant cyanobacterial blooms affect submerged macrophytes,the submerged plant Myriophyllum spicatum was exposed to cell extracts from microcystin(MC)-and non-MC-producing Microcystis strains in a laboratory experiment.Results showed that both Mcracystis cell extracts exerted obvious damages to plant biomass,photosynthesis,primary and secondary metabolism measures,and resistance of plant antioxidant systems,with MC-producing Microcystis having stronger effects due to the presence of MCs.Cyanotoxins other than MCs responsible for the negative effects from both strains needs further identification.The Shannon diversity and Chao1 indices of epiphytic and planktonic bacteria were decreased by the cell extracts from both Microcystis strains.However,epiphytic and planktonic bacterial communities responded differently to cell extracts at the genus level.The dominant genera of planktonic bacteria including Enterobacter,Pseudomonas,and Novosphingobium from phylum Proteobacteria,Chryseobacterium from phylum Bacteroidetes,and Microbacterium from Actinobacteriota in the treatments with cell extracts were previously reported to have strains with algicidal and MC-degrading capabilities.B acterial genes associated with energy production and conversion,amino acid transport and metabolism,and inorganic ion transport and metabolism,were more abundant in both treatments than the control for planktonic bacteria,but less abundant for epiphytic bacteria.We speculate that planktonic bacterial communities have the potential to use and degrade substances derived from Microcystis cell extracts,which may be beneficial for M.spicatum to alleviate damages from Microcystis.Further research is needed to verify the structure and function dynamics of epiphytic and planktonic bacteria in the interaction between cyanobacteria and submerged macrophytes.展开更多
To assess uncertainty of determination of MC-LR in environmental samples by solid phase extraction- ultra performance liquid chromatography- tandem mass spectrometry,the sources of the uncertainty were evaluated first...To assess uncertainty of determination of MC-LR in environmental samples by solid phase extraction- ultra performance liquid chromatography- tandem mass spectrometry,the sources of the uncertainty were evaluated firstly,and the expanded uncertainty was calculated finally.The results show that when MC-LR concentration in the water samples was 0.50 μg/L,the expanded uncertainty was 0.00628 μg/L(k=2).展开更多
Cyanobacterial populations in surface waters, including drinking water supplies and recreational waters, represent an ever present challenge for resource managers. As communities continuously respond to external and i...Cyanobacterial populations in surface waters, including drinking water supplies and recreational waters, represent an ever present challenge for resource managers. As communities continuously respond to external and internal processes, dynamic profiles of composition, dominance, growth and toxigenicity emerge. In this study measures of size structure and biomass, quantified using light microscopy and fluorometry, were used to estimate microcystin concentrations through linear regression analysis. Toxigenic profiles using cyanobacterial biomass were developed for lakes dominated by Microcystis spp. and Dolichospermum spp., influenced by both genus-specific pigment concentrations as well as microcystin concentrations. Community composition (Log %MIC) and biomass were used to describe microcystin concentrations in mixed assemblages, where composition was the first input variable. The accessory photopigment phycocyanin was used to describe the linear relationship between the daily growth and net microcystin production rates in the bloom-forming Microcystis spp. samples, suggesting that this size-fractionated sample may provide indications of potential toxigenicity in the whole lake water sample. Future investigations using fluorometric evaluation of cyanobacterial populations could provide additional applications and metrics for use by resource managers to quantify risk association with elevated cyanotoxin concentrations.展开更多
This study determined the levels of microcystins in water and fish from Phayao Lake, Phayao Province and selected fish ponds along the Ing River tributary in Chiang Rai Province. Samples were collected monthly for 8 m...This study determined the levels of microcystins in water and fish from Phayao Lake, Phayao Province and selected fish ponds along the Ing River tributary in Chiang Rai Province. Samples were collected monthly for 8 months (January to August 2011 for Phayao Lake, and November 2008 to June 2009 for fish ponds) and were analyzed by HPLC. The highest total microcystin-LR levels in water and fish in Phayao Lake were recorded in April 2010 at 2.60 ± 2.48 μg·L-1 and 0.20 ± 0.03 μg·kg-1 dry weight, respectively. Microcystis aeruginosa Kütz were the dominant species (271.6 ± 72.4 mm3/m3) in the lake. Colony number of Microcystis spp showed a positive correlation with soluble orthophosphate (r2 = 0.77). Similarly, Nile tilapia ponds surveyed along the tributary in Chiang Rai were contaminated with microcystins as well. The highest concentration detected in water was in March 2009 (0.58 ± 0.24 μg·L-1), whilst the maximum concentration in fish was recorded in April 2009 (2.68 ± 0.51 μg·kg-1 dry weight). Microcystis spp. dominated the pond waters and was positively correlated with chlorophyll a (r2=0.80) and soluble nitrate (r2=0.71). The highest concentration of the cyanobacteria was recorded in February 2009 at 4272.5 ± 62.3 mm3/m3. Results showed that total microcystin-LR concentration in fish in Chiang Rai ponds were higher than in Phayao Lake. This study suggested the possible health risks associated with the bioaccumulation of microcystins in fish (Nile tilapia) cultivated in fish ponds along the tributary in Chiang Rai and in Phayao Lake.展开更多
Different temperatures of water bath was used to extract the intracellular microcystin-LR(MC-LR) of Microcystis aeruginosa. Researching the extraction efficiency under the suitable temperature, so that it could find o...Different temperatures of water bath was used to extract the intracellular microcystin-LR(MC-LR) of Microcystis aeruginosa. Researching the extraction efficiency under the suitable temperature, so that it could find out the best temperature and time for extracting MC-LR from Microcystis aeruginosa cells. Five equal Microcystis aeruginosa was used to find out the best temperature, extracting at 60℃, 70℃, 80℃, 90℃ and 100℃ for 15 minutes, respectively. Results showed that the content of MC-LR extracted with the water under 100℃ was the highest. But meanwhile, the type and the content of impurities was the highest, too. In addition, another six equal Microcystis aeruginosa was extract with the water under 100℃ for 5min, 10 min, 15 min, 20 min, 25 min and 30 min respectively. It was proved that 20 minutes was enough for extracting MC-LR from Microcystis aeruginosa, no long time was needed.展开更多
This study investigates the photocatalytic degradation of microcystin-LR (MC-LR) under simulated solar light using Pt modified nano-sized tungsten trioxides (Pt/WO3). Photocatalytic activity was higher during the degr...This study investigates the photocatalytic degradation of microcystin-LR (MC-LR) under simulated solar light using Pt modified nano-sized tungsten trioxides (Pt/WO3). Photocatalytic activity was higher during the degradation of MC-LR with Pt/WO 3 than with pure WO 3 or Ti O2 . The catalyst loading greatly affect the degradation performance. The rate of degradation is influenced by the initial pH of the reaction solution. This study also investigates the photocatalytic inactivation of cyanobacteria. The results show that the algal growth was successfully controlled by the Pt/W O 3 . This study suggests Pt/W O 3 photocatalytic oxidation with solar light is a promising treatment for water containing MC-LR.展开更多
The effects of light, temperature, and coculture on the intracellular microcystin-LR(MCLR) quota of M icrocystis aeruginosa were evaluated based on coculture experiments with nontoxic Dolichospermum( Anabaena) fl os- ...The effects of light, temperature, and coculture on the intracellular microcystin-LR(MCLR) quota of M icrocystis aeruginosa were evaluated based on coculture experiments with nontoxic Dolichospermum( Anabaena) fl os- aquae. The MC-LR quota and transcription of m cy B and m cy D genes encoding MC synthetases in M. aeruginosa were evaluated on the basis of cell counts, high-performance liquid chromatography, and reverse-transcription quantitative real-time PCR. The MC-LR quotas of M. aeruginosa in coculture with a 1/1 ratio of inoculum of the two species were signifi cantly lower relative to monocultures 6-d after inoculation. Decreased MC-LR quotas under coculture conditions were enhanced by increasing the D. fl os- aquae to M. aeruginosa ratio in the inoculum and by environmental factors, such as temperature and light intensity. Moreover, the transcriptional concentrations of mcy B and mcy D genes in M. aeruginosa were signifi cantly inhibited by D. fl os- aquae competition in coculture(P <0.01), lowered to 20% of initial concentrations within 8 days. These data suggested that coculture effects by D. fl os- aquae not only reduced M. aeruginosa 's intracellular MC-LR quota via inhibition of genes encoding MC synthetases, but also that this effect was regulated by environmental factors, including temperature and light intensities.展开更多
Microcystins(MCs) are produced by certain bloomforming cyanobacteria that can induce toxicity in various organs, including renal toxicity, reproductive toxicity, cardiotoxicity, and immunosuppressive effects. It has b...Microcystins(MCs) are produced by certain bloomforming cyanobacteria that can induce toxicity in various organs, including renal toxicity, reproductive toxicity, cardiotoxicity, and immunosuppressive effects. It has been a significant global environmental issue due to its harm to the aquatic environment and human health. Numerous investigators have demonstrated that MC exposure can induce a widespread epidemic of enterogastritis with symptoms similar to food poisoning in areas close to lakes. Both in vivo and in vitro studies have provided evidence of positive associations between MC exposure and gastrointestinal toxicity. The toxicity of MCs on the gastrointestinal tract is multidimensional. MCs can affect gastrointestinal barrier function and shift the structure of gut microbiota in different gut regions. Furthermore, MCs can inhibit the secretion of gastrointestinal digestive enzymes and the release of inflammatory cytokines, which affects the expression of immune-related genes in the intestine. The damage of the intestine is closely correlated to MC exposure because the intestine is the main site for the digestion and absorption of nutrients. The damage to the gastrointestinal tract due to MCs was summarized from different aspects, which can be used as a foundation for further exploration of molecular damage mechanisms.展开更多
Twenty water bodies in China were sampled,and 186 strains of different Microcystis species were isolated,from which eight morpho species were identified and 43 stains containing the mcyB gene were detected.Phylogeneti...Twenty water bodies in China were sampled,and 186 strains of different Microcystis species were isolated,from which eight morpho species were identified and 43 stains containing the mcyB gene were detected.Phylogenetic analysis based on the mcyB gene indicated that the microcystin(MC)-producing Microcystis in China could be divided into two groups(ⅠandⅡ)and showed significant differences between the two groups.The maximum sequence similarity was 69.1%.Microcystins(MCs)were measured by high-performance liquid chromatography(HPLC)analysis,and no microcystin-RR(MC-RR)was detected in some strains belonging to GroupⅡ.Compared to other regions of the world,the proportion of Chinese MC-producing was different,and the regional differences were more obvious.A whole-cell polymerase chain reactio(PCR)assay was conducted to analyze the proportion of the mcyB gene in the laboratory cultured and field cultured Microcystis.The proportion of four morphospecies(M.vividis,M.ichthyoblabe,M.novacekii,and M.aeruginosa)that contained the mcyB gene exceeded 50%in the field cultured sample s.Compared with former studies,M.aeruginosa was the mo st likely morphotype that can produce MCs in the world.This study provided new insight of Microcystis hazard assessment and field monitoring.展开更多
A method of rapidly detecting three kinds of microcystins( MCs) in environmental water samples by using disk SPE- ultra high performance liquid chromatography- tandem mass spectrometry( UPLC- MS / MS) was established....A method of rapidly detecting three kinds of microcystins( MCs) in environmental water samples by using disk SPE- ultra high performance liquid chromatography- tandem mass spectrometry( UPLC- MS / MS) was established. Firstly,environmental water samples were extracted by disk SPE column( C_(18)),and three kinds of MCs were separated by Waters BEH C_(18) chromatographic column with acetonitrile- 0. 2% formic acid solution as the mobile phase. After the gradient elution separation,the external standard method was used for quantitative and qualitative analysis under MRM of UPLC- MS / MS. The results showed that the three kinds of MCs in the range of 0. 05- 10 μg / L showed good linear relation,and the correlation coefficients were higher than 0. 999 4,while the method detection limit was 0. 04 ng / L. Under 0. 1,1,and 5 μg / L standard addition for the same environmental sample,the average recovery was 82. 8%- 108. 8%,and the relative standard deviation of determination results was2. 1%- 10. 1%( n = 6). This method is rapid,sensitive and accurate,so it can be effectively applied in the monitoring of MCs in environmental water samples.展开更多
Three minor microcystins have been isolated from a Planktothrix rubescens strain.Their structures have been elucidated by one-and two-dimensional NMR spectroscopy and high-resolution tandem mass spectrometry as the co...Three minor microcystins have been isolated from a Planktothrix rubescens strain.Their structures have been elucidated by one-and two-dimensional NMR spectroscopy and high-resolution tandem mass spectrometry as the compounds[Asp^(3),(E)-Dhb^(7)]MC-LY(1),[Asp^(3),(E)-Dhb^(7)]MC-HtyW(2),and[Asp^(3),(E)-Dhb^(7)]MC-LW(3).The amino acids found at the variable positions 2 and 4 of the microcystin core structure are in accordance with the predicted amino acid substrate activation selectivities of the non-ribosomal peptide synthetases McyA and McyB described earlier for this strain.All structural microcystin variants produced by this strain were shown to inhibit protein phosphatase 1 in the nanomolar range.展开更多
Cyanobacterial blooms associated by their toxins have been increasing in frequency in fresh water bodies throughout the world. Among the cyanobacterial toxins, microcystins (MC) are the most common and cause severe ad...Cyanobacterial blooms associated by their toxins have been increasing in frequency in fresh water bodies throughout the world. Among the cyanobacterial toxins, microcystins (MC) are the most common and cause severe adverse impacts on plants, aquatic organisms and human beings. In this study, the effects of MC (at the concentrations of 20 and 200 μg·L-1) from field water and crude extract of cyanobacterial scum (mainly Microcystis spp.) from the Dau Tieng Reservoir, Vietnam, on the seedlings of three plants, Brassica rapa-chinensis, B. narinosa and Nasturtium officinale, were investigated for over a period of 7 days. The results showed that MC reduced the fresh weight, root and shoot length of the exposed seedlings. In addition, abnormalities of leaf shape and color of B. rapa-chinensis under exposure to MC were observed. The results implied that MC were taken up and might be accumulated in the seedlings possessing potential risk to consumers as seedlings of these plants are a common food source for Vietnamese. To the best of our knowledge, this is the first report on the effects of MC on B. rapa-chinensis, B. narinosa and N. officinale.展开更多
Phytoplankton including blue-green algal or cyanobacterial blooms frequently occurred in aquaculture ponds. Some cyanobacteria produced cyanotoxins that may accumulate in the food web and eventually in the aquaculture...Phytoplankton including blue-green algal or cyanobacterial blooms frequently occurred in aquaculture ponds. Some cyanobacteria produced cyanotoxins that may accumulate in the food web and eventually in the aquaculture products. In this study, accumulatation of microcystins in Nile tilapia (Oreochromis niloticus) and giant freshwater prawn (Macrobrachium rosenbergii) cultured in green water system was investigated.Nile tilapia was cultured in green water system and fish food;green water system with Microcystis aeruginosa Kützingand fish food and green water system with M. aeruginosa. Giant freshwater prawn was cultured: in green water systems with and without toxic M. aeruginosa. Microcystins of 8.32±0.76 and9.35±1.45μg·kg—1 d.w. were detected in fish cultured in green water system with M. aeruginosa and fish food and in green water system with M. aeruginosa, respectively. Microcystins of 14.42±1.63 μg·kg—1 was found in prawn samples. It implied that aquaculture products were likely to be contaminated with microcystins. This finding is useful for aquaculture in terms of food safety.展开更多
Immunoassays are widely used biochemical techniques to detect microcystins in environmental samples. The use of immunoassays for the detection of microcystins is vulnerable to matrix components and other interferents....Immunoassays are widely used biochemical techniques to detect microcystins in environmental samples. The use of immunoassays for the detection of microcystins is vulnerable to matrix components and other interferents. This study is an evaluation of the effects of interfering substances commonly found in drinking and ambient water samples using commercially-available immunoassay kits for microcystin toxins. The microplate and strip test immunoassay formats were tested in the study. For the microplate ELISA, the following were found to inhibit microcystin-LR (MC-LR) detection: 250 μg/mL Ca2+ or Mg2+, 0.01% ascorbic acid, 0.1% EDTA chelating agent, 0.05 M glycine-HCl, pH 3. The following exhibited no effect: sodium chloride (NaCl, 1% to 4%) and sodium thiosulfate (0.001% and 0.01%), 0.01 to 0.1 M phosphate buffers (PB), pH 7 and 0.067 M PB at pH 5, 6, 7 and 8. Overall, up to 50 μg/mL of standard and reference natural organic matter (NOM) from various sources did not interfere in the assay system (without MC-LR) but diminished the detection of MC-LR at varying degrees. This is the first study evaluating standard and reference humic and fulvic acids from various sources in immunoassays for microcystins. The strip test also showed variable effects on MC-LR detection in the presence of NOM. This assay format was also sensitive to varying pHs and ionic strengths. MC-LR binding was inhibited at low pH (0.05 M glycine-HCl, pH 3), whereas, 0.067 M PB with pH 6, 7 and 8 can yield false positive results. Lower ionic strength of 0.01 M PB, pH 7 showed no interference in MC-LR binding whereas higher ionic strengths can interfere with MC-LR detection. NaCl at 3% and 4% can interfere with the analysis giving false positive results. Mg2+ at 50 and 250 μg/mL showed no effect on the analysis while the same concentration of Ca2+ can yield false positive results. The performance in marine, brackish and hard waters should be tested given the potential sensitivity to salinity. Results of this study may assist in the further refinement of existing assays and the development of practical antibody-based methods to clean-up samples and detect cyanotoxins in water.展开更多
文摘Seven types of microcystins,isolated from Microcystis waterbloom in Lake Dalai,were characterized.The major toxins:MCYST-LR,MCYST-RR,[D-Asp<sup>3</sup>]MCYST-LR and[Dha<sup>7</sup>]MCYST-LR were identified by high performance liquid chromatography（HPLC）,as com-pared with the authentic microcystins.The minor toxins:MCYST FR,[L-Mser<sup>7</sup>]MCYST-LRand an unknown MCYST which was most likely to be MCYST-（H<sub>4</sub>）YR were identified with frit-fast atom bombardment liquid chromatography/mass spectrometry（Frit-FAB LC/MS）and aminoacid analysis.The toxigenic diversity in blue-green algae（cyanobacteria）was discussed.
基金Supported by the National Program for the Introduction of High-end Foreign Experts(No.G2021026024L)the National Natural Science Foundation of China(Nos.31700405,U1904124)+1 种基金the Major Public Welfare Projects in Henan Province(No.201300311300)the Breeding Project of Henan Normal University(No.HNU2021PL05)。
文摘To explore how decomposed Microcystis-dominant cyanobacterial blooms affect submerged macrophytes,the submerged plant Myriophyllum spicatum was exposed to cell extracts from microcystin(MC)-and non-MC-producing Microcystis strains in a laboratory experiment.Results showed that both Mcracystis cell extracts exerted obvious damages to plant biomass,photosynthesis,primary and secondary metabolism measures,and resistance of plant antioxidant systems,with MC-producing Microcystis having stronger effects due to the presence of MCs.Cyanotoxins other than MCs responsible for the negative effects from both strains needs further identification.The Shannon diversity and Chao1 indices of epiphytic and planktonic bacteria were decreased by the cell extracts from both Microcystis strains.However,epiphytic and planktonic bacterial communities responded differently to cell extracts at the genus level.The dominant genera of planktonic bacteria including Enterobacter,Pseudomonas,and Novosphingobium from phylum Proteobacteria,Chryseobacterium from phylum Bacteroidetes,and Microbacterium from Actinobacteriota in the treatments with cell extracts were previously reported to have strains with algicidal and MC-degrading capabilities.B acterial genes associated with energy production and conversion,amino acid transport and metabolism,and inorganic ion transport and metabolism,were more abundant in both treatments than the control for planktonic bacteria,but less abundant for epiphytic bacteria.We speculate that planktonic bacterial communities have the potential to use and degrade substances derived from Microcystis cell extracts,which may be beneficial for M.spicatum to alleviate damages from Microcystis.Further research is needed to verify the structure and function dynamics of epiphytic and planktonic bacteria in the interaction between cyanobacteria and submerged macrophytes.
文摘To assess uncertainty of determination of MC-LR in environmental samples by solid phase extraction- ultra performance liquid chromatography- tandem mass spectrometry,the sources of the uncertainty were evaluated firstly,and the expanded uncertainty was calculated finally.The results show that when MC-LR concentration in the water samples was 0.50 μg/L,the expanded uncertainty was 0.00628 μg/L(k=2).
文摘Cyanobacterial populations in surface waters, including drinking water supplies and recreational waters, represent an ever present challenge for resource managers. As communities continuously respond to external and internal processes, dynamic profiles of composition, dominance, growth and toxigenicity emerge. In this study measures of size structure and biomass, quantified using light microscopy and fluorometry, were used to estimate microcystin concentrations through linear regression analysis. Toxigenic profiles using cyanobacterial biomass were developed for lakes dominated by Microcystis spp. and Dolichospermum spp., influenced by both genus-specific pigment concentrations as well as microcystin concentrations. Community composition (Log %MIC) and biomass were used to describe microcystin concentrations in mixed assemblages, where composition was the first input variable. The accessory photopigment phycocyanin was used to describe the linear relationship between the daily growth and net microcystin production rates in the bloom-forming Microcystis spp. samples, suggesting that this size-fractionated sample may provide indications of potential toxigenicity in the whole lake water sample. Future investigations using fluorometric evaluation of cyanobacterial populations could provide additional applications and metrics for use by resource managers to quantify risk association with elevated cyanotoxin concentrations.
文摘This study determined the levels of microcystins in water and fish from Phayao Lake, Phayao Province and selected fish ponds along the Ing River tributary in Chiang Rai Province. Samples were collected monthly for 8 months (January to August 2011 for Phayao Lake, and November 2008 to June 2009 for fish ponds) and were analyzed by HPLC. The highest total microcystin-LR levels in water and fish in Phayao Lake were recorded in April 2010 at 2.60 ± 2.48 μg·L-1 and 0.20 ± 0.03 μg·kg-1 dry weight, respectively. Microcystis aeruginosa Kütz were the dominant species (271.6 ± 72.4 mm3/m3) in the lake. Colony number of Microcystis spp showed a positive correlation with soluble orthophosphate (r2 = 0.77). Similarly, Nile tilapia ponds surveyed along the tributary in Chiang Rai were contaminated with microcystins as well. The highest concentration detected in water was in March 2009 (0.58 ± 0.24 μg·L-1), whilst the maximum concentration in fish was recorded in April 2009 (2.68 ± 0.51 μg·kg-1 dry weight). Microcystis spp. dominated the pond waters and was positively correlated with chlorophyll a (r2=0.80) and soluble nitrate (r2=0.71). The highest concentration of the cyanobacteria was recorded in February 2009 at 4272.5 ± 62.3 mm3/m3. Results showed that total microcystin-LR concentration in fish in Chiang Rai ponds were higher than in Phayao Lake. This study suggested the possible health risks associated with the bioaccumulation of microcystins in fish (Nile tilapia) cultivated in fish ponds along the tributary in Chiang Rai and in Phayao Lake.
文摘Different temperatures of water bath was used to extract the intracellular microcystin-LR(MC-LR) of Microcystis aeruginosa. Researching the extraction efficiency under the suitable temperature, so that it could find out the best temperature and time for extracting MC-LR from Microcystis aeruginosa cells. Five equal Microcystis aeruginosa was used to find out the best temperature, extracting at 60℃, 70℃, 80℃, 90℃ and 100℃ for 15 minutes, respectively. Results showed that the content of MC-LR extracted with the water under 100℃ was the highest. But meanwhile, the type and the content of impurities was the highest, too. In addition, another six equal Microcystis aeruginosa was extract with the water under 100℃ for 5min, 10 min, 15 min, 20 min, 25 min and 30 min respectively. It was proved that 20 minutes was enough for extracting MC-LR from Microcystis aeruginosa, no long time was needed.
文摘This study investigates the photocatalytic degradation of microcystin-LR (MC-LR) under simulated solar light using Pt modified nano-sized tungsten trioxides (Pt/WO3). Photocatalytic activity was higher during the degradation of MC-LR with Pt/WO 3 than with pure WO 3 or Ti O2 . The catalyst loading greatly affect the degradation performance. The rate of degradation is influenced by the initial pH of the reaction solution. This study also investigates the photocatalytic inactivation of cyanobacteria. The results show that the algal growth was successfully controlled by the Pt/W O 3 . This study suggests Pt/W O 3 photocatalytic oxidation with solar light is a promising treatment for water containing MC-LR.
基金Supported by the National Natural Science Foundation of China(Nos.31471810,31272081)the Major Science and Technology Program for Water Pollution Control and Treatment(No.2012ZX07101-013-05(02))the Jiangsu Key Technology R&D Program(No.BE2012372)
文摘The effects of light, temperature, and coculture on the intracellular microcystin-LR(MCLR) quota of M icrocystis aeruginosa were evaluated based on coculture experiments with nontoxic Dolichospermum( Anabaena) fl os- aquae. The MC-LR quota and transcription of m cy B and m cy D genes encoding MC synthetases in M. aeruginosa were evaluated on the basis of cell counts, high-performance liquid chromatography, and reverse-transcription quantitative real-time PCR. The MC-LR quotas of M. aeruginosa in coculture with a 1/1 ratio of inoculum of the two species were signifi cantly lower relative to monocultures 6-d after inoculation. Decreased MC-LR quotas under coculture conditions were enhanced by increasing the D. fl os- aquae to M. aeruginosa ratio in the inoculum and by environmental factors, such as temperature and light intensity. Moreover, the transcriptional concentrations of mcy B and mcy D genes in M. aeruginosa were signifi cantly inhibited by D. fl os- aquae competition in coculture(P <0.01), lowered to 20% of initial concentrations within 8 days. These data suggested that coculture effects by D. fl os- aquae not only reduced M. aeruginosa 's intracellular MC-LR quota via inhibition of genes encoding MC synthetases, but also that this effect was regulated by environmental factors, including temperature and light intensities.
基金Supported by Henan Natural Science Foundation,No.162300410267the National Nature Science Foundation of China,Nos.81773384 and 81472948
文摘Microcystins(MCs) are produced by certain bloomforming cyanobacteria that can induce toxicity in various organs, including renal toxicity, reproductive toxicity, cardiotoxicity, and immunosuppressive effects. It has been a significant global environmental issue due to its harm to the aquatic environment and human health. Numerous investigators have demonstrated that MC exposure can induce a widespread epidemic of enterogastritis with symptoms similar to food poisoning in areas close to lakes. Both in vivo and in vitro studies have provided evidence of positive associations between MC exposure and gastrointestinal toxicity. The toxicity of MCs on the gastrointestinal tract is multidimensional. MCs can affect gastrointestinal barrier function and shift the structure of gut microbiota in different gut regions. Furthermore, MCs can inhibit the secretion of gastrointestinal digestive enzymes and the release of inflammatory cytokines, which affects the expression of immune-related genes in the intestine. The damage of the intestine is closely correlated to MC exposure because the intestine is the main site for the digestion and absorption of nutrients. The damage to the gastrointestinal tract due to MCs was summarized from different aspects, which can be used as a foundation for further exploration of molecular damage mechanisms.
基金the Science and Technology Project of Henan Province(Nos.19A180018,192102310306)the Key Laboratory of Algal Biology,Institute of Hydrobiology,Chinese Academy of Sciences(No.2018001)。
文摘Twenty water bodies in China were sampled,and 186 strains of different Microcystis species were isolated,from which eight morpho species were identified and 43 stains containing the mcyB gene were detected.Phylogenetic analysis based on the mcyB gene indicated that the microcystin(MC)-producing Microcystis in China could be divided into two groups(ⅠandⅡ)and showed significant differences between the two groups.The maximum sequence similarity was 69.1%.Microcystins(MCs)were measured by high-performance liquid chromatography(HPLC)analysis,and no microcystin-RR(MC-RR)was detected in some strains belonging to GroupⅡ.Compared to other regions of the world,the proportion of Chinese MC-producing was different,and the regional differences were more obvious.A whole-cell polymerase chain reactio(PCR)assay was conducted to analyze the proportion of the mcyB gene in the laboratory cultured and field cultured Microcystis.The proportion of four morphospecies(M.vividis,M.ichthyoblabe,M.novacekii,and M.aeruginosa)that contained the mcyB gene exceeded 50%in the field cultured sample s.Compared with former studies,M.aeruginosa was the mo st likely morphotype that can produce MCs in the world.This study provided new insight of Microcystis hazard assessment and field monitoring.
文摘A method of rapidly detecting three kinds of microcystins( MCs) in environmental water samples by using disk SPE- ultra high performance liquid chromatography- tandem mass spectrometry( UPLC- MS / MS) was established. Firstly,environmental water samples were extracted by disk SPE column( C_(18)),and three kinds of MCs were separated by Waters BEH C_(18) chromatographic column with acetonitrile- 0. 2% formic acid solution as the mobile phase. After the gradient elution separation,the external standard method was used for quantitative and qualitative analysis under MRM of UPLC- MS / MS. The results showed that the three kinds of MCs in the range of 0. 05- 10 μg / L showed good linear relation,and the correlation coefficients were higher than 0. 999 4,while the method detection limit was 0. 04 ng / L. Under 0. 1,1,and 5 μg / L standard addition for the same environmental sample,the average recovery was 82. 8%- 108. 8%,and the relative standard deviation of determination results was2. 1%- 10. 1%( n = 6). This method is rapid,sensitive and accurate,so it can be effectively applied in the monitoring of MCs in environmental water samples.
基金supported by the German Federal Ministry of Economics and Technology(KF2766301SB0)the Leibniz-Institut fur Molekulare Phamakologie(FMP),the Austrian Science Fund(P24070)the Austrian Climate Research Program(ACRP)project RADICAL(Risk Analysis of Direct and Indirect Climate effects on deep Austrian Lake Ecosystems).
文摘Three minor microcystins have been isolated from a Planktothrix rubescens strain.Their structures have been elucidated by one-and two-dimensional NMR spectroscopy and high-resolution tandem mass spectrometry as the compounds[Asp^(3),(E)-Dhb^(7)]MC-LY(1),[Asp^(3),(E)-Dhb^(7)]MC-HtyW(2),and[Asp^(3),(E)-Dhb^(7)]MC-LW(3).The amino acids found at the variable positions 2 and 4 of the microcystin core structure are in accordance with the predicted amino acid substrate activation selectivities of the non-ribosomal peptide synthetases McyA and McyB described earlier for this strain.All structural microcystin variants produced by this strain were shown to inhibit protein phosphatase 1 in the nanomolar range.
文摘Cyanobacterial blooms associated by their toxins have been increasing in frequency in fresh water bodies throughout the world. Among the cyanobacterial toxins, microcystins (MC) are the most common and cause severe adverse impacts on plants, aquatic organisms and human beings. In this study, the effects of MC (at the concentrations of 20 and 200 μg·L-1) from field water and crude extract of cyanobacterial scum (mainly Microcystis spp.) from the Dau Tieng Reservoir, Vietnam, on the seedlings of three plants, Brassica rapa-chinensis, B. narinosa and Nasturtium officinale, were investigated for over a period of 7 days. The results showed that MC reduced the fresh weight, root and shoot length of the exposed seedlings. In addition, abnormalities of leaf shape and color of B. rapa-chinensis under exposure to MC were observed. The results implied that MC were taken up and might be accumulated in the seedlings possessing potential risk to consumers as seedlings of these plants are a common food source for Vietnamese. To the best of our knowledge, this is the first report on the effects of MC on B. rapa-chinensis, B. narinosa and N. officinale.
文摘Phytoplankton including blue-green algal or cyanobacterial blooms frequently occurred in aquaculture ponds. Some cyanobacteria produced cyanotoxins that may accumulate in the food web and eventually in the aquaculture products. In this study, accumulatation of microcystins in Nile tilapia (Oreochromis niloticus) and giant freshwater prawn (Macrobrachium rosenbergii) cultured in green water system was investigated.Nile tilapia was cultured in green water system and fish food;green water system with Microcystis aeruginosa Kützingand fish food and green water system with M. aeruginosa. Giant freshwater prawn was cultured: in green water systems with and without toxic M. aeruginosa. Microcystins of 8.32±0.76 and9.35±1.45μg·kg—1 d.w. were detected in fish cultured in green water system with M. aeruginosa and fish food and in green water system with M. aeruginosa, respectively. Microcystins of 14.42±1.63 μg·kg—1 was found in prawn samples. It implied that aquaculture products were likely to be contaminated with microcystins. This finding is useful for aquaculture in terms of food safety.
文摘Immunoassays are widely used biochemical techniques to detect microcystins in environmental samples. The use of immunoassays for the detection of microcystins is vulnerable to matrix components and other interferents. This study is an evaluation of the effects of interfering substances commonly found in drinking and ambient water samples using commercially-available immunoassay kits for microcystin toxins. The microplate and strip test immunoassay formats were tested in the study. For the microplate ELISA, the following were found to inhibit microcystin-LR (MC-LR) detection: 250 μg/mL Ca2+ or Mg2+, 0.01% ascorbic acid, 0.1% EDTA chelating agent, 0.05 M glycine-HCl, pH 3. The following exhibited no effect: sodium chloride (NaCl, 1% to 4%) and sodium thiosulfate (0.001% and 0.01%), 0.01 to 0.1 M phosphate buffers (PB), pH 7 and 0.067 M PB at pH 5, 6, 7 and 8. Overall, up to 50 μg/mL of standard and reference natural organic matter (NOM) from various sources did not interfere in the assay system (without MC-LR) but diminished the detection of MC-LR at varying degrees. This is the first study evaluating standard and reference humic and fulvic acids from various sources in immunoassays for microcystins. The strip test also showed variable effects on MC-LR detection in the presence of NOM. This assay format was also sensitive to varying pHs and ionic strengths. MC-LR binding was inhibited at low pH (0.05 M glycine-HCl, pH 3), whereas, 0.067 M PB with pH 6, 7 and 8 can yield false positive results. Lower ionic strength of 0.01 M PB, pH 7 showed no interference in MC-LR binding whereas higher ionic strengths can interfere with MC-LR detection. NaCl at 3% and 4% can interfere with the analysis giving false positive results. Mg2+ at 50 and 250 μg/mL showed no effect on the analysis while the same concentration of Ca2+ can yield false positive results. The performance in marine, brackish and hard waters should be tested given the potential sensitivity to salinity. Results of this study may assist in the further refinement of existing assays and the development of practical antibody-based methods to clean-up samples and detect cyanotoxins in water.
