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Guo Y, Zhao X, Yao Z, Qian Z, Wang Y, Xian Q. The effects of exogenous amino acids on production of microcystin variants in Microcystis aeruginosa. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2023; 259:106525. [PMID: 37087861 DOI: 10.1016/j.aquatox.2023.106525] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 03/25/2023] [Accepted: 04/05/2023] [Indexed: 05/03/2023]
Abstract
Dissolved free amino acids are a significant component of dissolved organic nitrogen (DON) in natural waterbodies. The effects of four amino acids (glutamic acid, phenylalanine, leucine, and arginine) on the growth and microcystins (MCs) production of Microcystis aeruginosa were studied in batch culture. The profiles of five MCs variants and the expression levels of target genes involved in MCs biosynthesis and nitrogen metabolism were measured. When amino acids were used as the sole nitrogen source instead of nitrate at different levels (0.5, 2.0 and 8.0 mg/L based on N) in BG-11 medium, algal cell growth and intracellular MCs quotas were inhibited slightly by the treatments with glutamic acid and arginine. The treatments with phenylalanine and leucine, on the other hand, had a strong inhibitory effect on algal cell growth and MCs production. Moreover, the concentrations of Chlorophyll a, phycocyanin and allophycocyanin in cells cultured in glutamic acid, leucine and phenylalanine were lower than those in the control group with nitrate as nitrogen source. The existence of leucine or phenylalanine can lead to a significant increase in the relative abundance of MCs variants structured with the corresponding amino acids. The expression of microcystin-producing gene mcyD was downregulated while the gene pipX associated with nitrogen metabolism was upregulated during the cultivation of M. aeruginosa with amino acids as sole nitrogen source. M. aeruginosa undergoes significant alterations due to exogenous amino acids and exhibits advanced strategies for MCs production.
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Affiliation(s)
- Yaxin Guo
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Xiating Zhao
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Zongcheng Yao
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Zongyao Qian
- Guangxi Key Laboratory of Karst Ecological Processes and Services, Huanjiang Observation and Research Station for Karst Ecosystems, Chinese Academy of Sciences, Huanjiang 547100, China
| | - Yuting Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Qiming Xian
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
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2
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Zhao Y, Wang Z, Chen M, Huang X, Luo Z. Effects of nitrogen to phosphorus ratios on algal growth and arsenate metabolism by Microcystis aeruginosa with dissolved organic phosphorus and nitrate as nutrients. ALGAL RES 2023. [DOI: 10.1016/j.algal.2022.102922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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3
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Hellweger FL, Martin RM, Eigemann F, Smith DJ, Dick GJ, Wilhelm SW. Models predict planned phosphorus load reduction will make Lake Erie more toxic. Science 2022; 376:1001-1005. [PMID: 35617400 DOI: 10.1126/science.abm6791] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Harmful cyanobacteria are a global environmental problem, yet we lack actionable understanding of toxigenic versus nontoxigenic strain ecology and toxin production. We performed a large-scale meta-analysis including 103 papers and used it to develop a mechanistic, agent-based model of Microcystis growth and microcystin production. Simulations for Lake Erie suggest that the observed toxigenic-to-nontoxigenic strain succession during the 2014 Toledo drinking water crisis was controlled by different cellular oxidative stress mitigation strategies (protection by microcystin versus degradation by enzymes) and the different susceptibility of those mechanisms to nitrogen limitation. This model, as well as a simpler empirical one, predicts that the planned phosphorus load reduction will lower biomass but make nitrogen and light more available, which will increase toxin production, favor toxigenic cells, and increase toxin concentrations.
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Affiliation(s)
- Ferdi L Hellweger
- Water Quality Engineering, Technical University of Berlin, Berlin, Germany
| | - Robbie M Martin
- Department of Microbiology, University of Tennessee, Knoxville, TN, USA
| | - Falk Eigemann
- Water Quality Engineering, Technical University of Berlin, Berlin, Germany
| | - Derek J Smith
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Gregory J Dick
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA.,Cooperative Institute for Great Lakes Research, University of Michigan, Ann Arbor, MI, USA
| | - Steven W Wilhelm
- Department of Microbiology, University of Tennessee, Knoxville, TN, USA
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4
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Qi J, Ma B, Miao S, Liu R, Hu C, Qu J. Pre-oxidation enhanced cyanobacteria removal in drinking water treatment: A review. J Environ Sci (China) 2021; 110:160-168. [PMID: 34593187 DOI: 10.1016/j.jes.2021.03.040] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 03/15/2021] [Indexed: 06/13/2023]
Abstract
Cyanobacterial bloom has many adverse effects on source water quality and drinking water production. The traditional water treatment process can hardly achieve satisfactory removal of algae cells. This review examines the impact of pre-oxidation on the removal of cyanobacteria by solid-liquid separation processes. It was reported that the introduction of chemical oxidants such as chlorine, potassium permanganate, and ozone in algae-laden water pretreatment could improve algae removal by the subsequent solid-liquid separation processes. However, over dosed oxidants can result in more serious water quality risks due to significant algae cell lysis and undesirable intracellular organic matter release. It was suggested that moderate pre-oxidation may enhance the removal of cyanobacteria without damaging algae cells. In this article, effects of moderate pretreatment on the solid-liquid separation processes (sedimentation, dissolved air flotation, and membrane filtration) are reviewed.
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Affiliation(s)
- Jing Qi
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Baiwen Ma
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shiyu Miao
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ruiping Liu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Chengzhi Hu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Jiuhui Qu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
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5
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Li B, Liu Y, Zhang H, Liu Y, Liu Y, Xie P. Research progress in the functionalization of microcystin-LR based on interdisciplinary technologies. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.214041] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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6
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Zhang Q, Chen Y, Wang M, Zhang J, Chen Q, Liu D. Molecular responses to inorganic and organic phosphorus sources in the growth and toxin formation of Microcystis aeruginosa. WATER RESEARCH 2021; 196:117048. [PMID: 33773451 DOI: 10.1016/j.watres.2021.117048] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/04/2021] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
Toxic cyanobacteria bloom is a ubiquitous phenomenon worldwide in eutrophic lakes or reservoirs. Microcystis, is a cosmopolitan genus in cyanobacteria and exists in many different forms. Microcystis aeruginosa (M. aeruginosa) can produce microcystins (MCs) with strong liver toxicity during its growth and decomposition. Phosphorus (P) is a typical growth limiting factor of M. aeruginosa. Though different forms and concentrations of P are common in natural water, the molecular responses in the growth and MCs formation of M. aeruginosa remain unclear. In this study, laboratory experiments were conducted to determine the uptake of P, cell activity, MCs release, and related gene expression under different concentrations of dissolved inorganic phosphorus (DIP) and dissolved organic phosphorus (DOP). We found that the growth of M. aeruginosa was promoted by increasing DIP concentration but coerced under high concentration (0.6 and 1.0 mg P/L) of DOP after P starvation. The growth stress was not related to the alkaline phosphatase activity (APA). Although alkaline phosphatase (AP) could convert DOP into algae absorbable DIP, the growth status of M. aeruginosa mainly depended on the response mechanism of phosphate transporter expression to the extracellular P concentration. High-concentration DIP promoted MCs production in M. aeruginosa, while high-concentration DOP triggered the release of intracellular MCs rather than affecting MCs production. Our study revealed the molecular responses of algal growth and toxin formation under different P sources, and provided a theoretical basis and novel idea for risk management of eutrophic lakes and reservoirs.
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Affiliation(s)
- Qi Zhang
- State Key Laboratory of Hydrology-Water Resources & Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210029, China; Center for Eco-Environment Research, Nanjing Hydraulic Research Institute, Nanjing 210029, China
| | - Yuchen Chen
- Center for Eco-Environment Research, Nanjing Hydraulic Research Institute, Nanjing 210029, China
| | - Min Wang
- Center for Eco-Environment Research, Nanjing Hydraulic Research Institute, Nanjing 210029, China
| | - Jianyun Zhang
- State Key Laboratory of Hydrology-Water Resources & Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210029, China; Yangtze Institute for Conservation and Green Development, Nanjing 210098, China
| | - Qiuwen Chen
- State Key Laboratory of Hydrology-Water Resources & Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210029, China; Yangtze Institute for Conservation and Green Development, Nanjing 210098, China.
| | - Dongsheng Liu
- Center for Eco-Environment Research, Nanjing Hydraulic Research Institute, Nanjing 210029, China
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Effects of Nutrient Limitation on the Synthesis of N-Rich Phytoplankton Toxins: A Meta-Analysis. Toxins (Basel) 2020; 12:toxins12040221. [PMID: 32244741 PMCID: PMC7232484 DOI: 10.3390/toxins12040221] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/11/2020] [Accepted: 03/12/2020] [Indexed: 11/21/2022] Open
Abstract
Eutrophication has played a major role in the worldwide increase of harmful algal blooms (HABs). Higher input of key nutrients, such as nitrogen (N) and phosphorus (P), can stimulate the growth of harmful algal species in freshwater, estuarine, and coastal marine ecosystems. Some HAB-forming taxa, particularly several cyanobacteria and dinoflagellate species, are harmful through the production of N-rich toxins that have detrimental effects on the environment and human health. Here, we test how changes in nutrient availability affect N-rich toxin synthesis in cyanobacteria and dinoflagellates using a meta-analysis approach. Overall, N-rich toxin content showed an increase with P limitation, while it tended to decrease with N limitation, but we also observed substantial variation in responses both within and across genera and toxin groups. For instance, in response to N limitation, microcystin content varied from a 297% decrease up to a 273% increase, and paralytic shellfish poisoning (PSP) toxin content varied from a 204% decrease to an 82% increase. Cylindrospermopsin, produced by N2-fixing cyanobacteria, showed no clear direction in response to nutrient limitation, and cellular contents of this compound may thus vary independently of nutrient fluctuations. Our results confirm earlier reported stoichiometric regulation of N-rich phytoplankton toxins, showing increased toxin content with an increase in cellular N:P ratios, and vice versa. Thus, changes in N-rich toxin content largely follow the changes in relative cellular N content. Consequently, although nutrient limitation may limit bloom biomass and thereby bloom toxicity, our results warn that P limitation can cause accumulation of cellular toxins and thus lead to unexpected increases in bloom toxicity.
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8
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Zhou Y, Li X, Xia Q, Dai R. Transcriptomic survey on the microcystins production and growth of Microcystis aeruginosa under nitrogen starvation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 700:134501. [PMID: 31689655 DOI: 10.1016/j.scitotenv.2019.134501] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/15/2019] [Accepted: 09/15/2019] [Indexed: 06/10/2023]
Abstract
Cyanobacteria are a vital component of freshwater phytoplankton, and many species are recognized for their ability to produce toxins and harmful algal blooms (HABs). Nitrogen is an essential element of all the complex macromolecules in algal cells. However, the underlying molecular mechanism of the changes in transcriptomic patterns and physiological responses in response to N starvation is poorly understood. The transcriptomes were generated via RNA-sequencing (RNA-Seq) technology to study the major metabolic pathway under N starvation. The results shed light on the mechanism of toxin production and physiological adaptations in Microcystis aeruginosa (M. aeruginosa). The cell density gradually increased during the first two days then declined over time and was finally stable at (15.50 ± 0.5) × 105 cell mL-1 after 6 days. The chlorophyll-a content and phycocyanin content of M. aeruginosa increased during the first two days and subsequently decreased markedly over time under N starvation. The variable to maximum chlorophyll fluorescence ratio (Fv/Fm ratio) decreased with time under N starvation. Most photosynthesis genes have similarity decreasing trends with growth physiological changes. The microcystins (MCs) levels generally increased first, reaching a peak value with 1.35 pg cell-1 on the fifth day, and then remained roughly constant. The genes involved in N metabolism-related gene expression were upregulated to maintain normal biological activity, while the genes involved in photosynthesis-related gene expression were downregulated to save energy. All genes encoding algae toxin synthesis were upregulated under N starvation. The observed expression patterns demonstrate that all MCs genes respond similarly to MCs production within the cell. Our results indicate the response mechanism of M. aeruginosa under N starvation and provide a comprehensive understanding of N-controlling cyanobacteria and MCs synthesis.
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Affiliation(s)
- Yanping Zhou
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Xuan Li
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Qiongqiong Xia
- North China Municipal Engineering Design & Research Institute Co. Ltd., Tianjin 300074, China
| | - Ruihua Dai
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
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9
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Lu KY, Chiu YT, Burch M, Senoro D, Lin TF. A molecular-based method to estimate the risk associated with cyanotoxins and odor compounds in drinking water sources. WATER RESEARCH 2019; 164:114938. [PMID: 31419667 DOI: 10.1016/j.watres.2019.114938] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 07/06/2019] [Accepted: 07/31/2019] [Indexed: 06/10/2023]
Abstract
A biomolecular-based monitoring approach for the assessment of water quality hazards and risks associated with cyanobacteria was developed and validated in drinking reservoirs in Taiwan and the Philippines. The approach was based upon the measurement of gene abundances of toxigenic Microcystis and Cylindrospermopsis; for cyanotoxins; and for aesthetically offensive earthy-musty odor compounds. This was compared to conventional monitoring approaches, which included cell enumeration by microscopy, and toxin and odor compound analysis by instrumental analytical methods and immunoassays as appropriate for the metabolites. The validation involved samples from ten major reservoirs on Taiwan's main island, nineteen reservoirs on the offshore islands, and Laguna de Bay in the Philippines. The gene-based approach was successfully validated statistically and compared to conventional widely utilized risk assessment schemes which have employed 'Alert Levels' for toxic cyanobacteria. In this case a new integrated scheme of 'Response Levels' is proposed which incorporates odor metabolite hazards in addition to cyanotoxins and is based upon gene copy numbers to derive quantitative triggers. The comprehensive scheme evaluated from these locations is considered to be more precise and efficient for both monitoring and as a risk assessment diagnostic tool, given that it offers the capacity for analysis of the abundance of genes for cyanobacterial metabolites in large numbers of natural water samples in a significantly reduced period of time compared to the approaches of cell enumeration by microscopy or metabolite analytical techniques. This approach is the first time both the hazard and risk for both odors and cyanotoxins from cyanobacteria have been considered together in a monitoring scheme and offers an improved means for determining the Response Levels in the risk assessment process for cyanobacteria and their metabolites in drinking water sources.
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Affiliation(s)
- Keng-Yu Lu
- Department of Environmental Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Yi-Ting Chiu
- Department of Environmental Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Michael Burch
- Department of Ecology and Evolutionary Biology, University of Adelaide, Adelaide, Australia
| | - Delia Senoro
- School of Civil, Environmental and Geological Engineering, Mapua University, Manila, Philippines
| | - Tsair-Fuh Lin
- Department of Environmental Engineering, National Cheng Kung University, Tainan, Taiwan.
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10
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Chen Q, Wang M, Zhang J, Shi W, Mynett AE, Yan H, Hu L. Physiological effects of nitrate, ammonium, and urea on the growth and microcystins contamination of Microcystis aeruginosa: Implication for nitrogen mitigation. WATER RESEARCH 2019; 163:114890. [PMID: 31351354 DOI: 10.1016/j.watres.2019.114890] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 07/18/2019] [Accepted: 07/19/2019] [Indexed: 05/03/2023]
Abstract
The effects of three commonly bioavailable nitrogen (N) sources (nitrate, ammonium, and urea) on regulating the growth and microcystins (MCs) production of Microcystis aeruginosa (M. aeruginosa) at environmentally relevant concentrations were investigated from a physiological perspective. Changes in amino acid quotas as well as the transcripts of target genes associated with N metabolism (ntcA, pipX and glnB) and toxin formation (mcyA and mcyD) were determined. Results indicated that increases in nitrate and urea concentrations enhanced M. aeruginosa growth, but high ammonium concentration (7 mg-N/L) suppressed the growth. The total intracellular MCs (IMCs) content was well correlated (0.65, p < 0.001) to amino acids (the sum of methionine, leucine, serine, alanine, arginine, glutamic acid, and aspartic acid) associated with MCs production. Ammonium favors amino acid synthesis in M. aeruginosa, thus cells grown under high concentrations of ammonium (7 mg-N/L) had sufficient precursors for MCs production, which might lead to higher IMCs. Both high and low ammonium concentration resulted in high total extracellular MCs (EMCs) level in water, despite of their different mechanisms. These results indicated that mitigation of nitrogen in eutrophic waters should be very cautious of unexpected risks, as the reduction of ammonium may have the risk of stimulating M. aeruginosa growth or increasing EMCs levels.
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Affiliation(s)
- Qiuwen Chen
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, 210029, China; Center for Eco-Environmental Research, Nanjing Hydraulic Research Institute, Nanjing, 210029, China.
| | - Min Wang
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, 210029, China; Center for Eco-Environmental Research, Nanjing Hydraulic Research Institute, Nanjing, 210029, China
| | - Jianyun Zhang
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, 210029, China.
| | - Wenqing Shi
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, 210029, China; Center for Eco-Environmental Research, Nanjing Hydraulic Research Institute, Nanjing, 210029, China
| | - Arthur E Mynett
- Center for Eco-Environmental Research, Nanjing Hydraulic Research Institute, Nanjing, 210029, China
| | - Hanlu Yan
- Center for Eco-Environmental Research, Nanjing Hydraulic Research Institute, Nanjing, 210029, China
| | - Liuming Hu
- Center for Eco-Environmental Research, Nanjing Hydraulic Research Institute, Nanjing, 210029, China
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Tilahun S, Kifle D, Zewde TW, Johansen JA, Demissie TB, Hansen JH. Temporal dynamics of intra-and extra-cellular microcystins concentrations in Koka reservoir (Ethiopia): Implications for public health risk. Toxicon 2019; 168:83-92. [DOI: 10.1016/j.toxicon.2019.06.217] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 06/08/2019] [Accepted: 06/16/2019] [Indexed: 10/26/2022]
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12
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Dai R, Zhou Y, Chen Y, Zhang X, Yan Y, An D. Effects of arginine on the growth and microcystin-LR production of Microcystis aeruginosa in culture. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 651:706-712. [PMID: 30245426 DOI: 10.1016/j.scitotenv.2018.09.213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/15/2018] [Accepted: 09/16/2018] [Indexed: 06/08/2023]
Abstract
Although toxic cyanobacterial blooms and their toxins threaten drinking water and ecology and are promoted by nutrient loading, the precise nutrient regime that increases cyanobacterial populations and toxin production is poorly understood. Here, the influences of arginine (Arg), as a common amino acid with high nitrogen content, on the growth and microcystins (MCs) production of Microcystis aeruginosa (M. aeruginosa) were investigated by an isotope method (15N). The results showed that the biomass and production of microcystin-LR (MC-LR) increased with an increase in initial Arg concentrations in the range of 0.3-1.4 mmol-N L-1, whereas a higher Arg concentration (3.6 mmol-N L-1) inhibited the growth. MC-LR on different days (days 0, 6, 12, and 18) was detected by liquid chromatography with tandem mass spectrometry (LC-MS/MS) after incubation with 15N-Arg. The MC-LR molecular weight increased from 995 to 1004 with 100% relative abundance with 10 15N atoms bound by the Adda, Arg (4 15N), Glu, Mdha, Ala, Leu, and MeAsp residues on day 18. It seems that there was a sequential order when M. aeruginosa assimilated Arg to synthesize MC-LR. The Arg residue in the molecule of MC-LR was the last one to be labeled by 15N from 15N-arginine. This study not only presents a deeper insight into the biosynthesis of free amino acids that are incorporated into MCs but also reminds us of the potential risk caused by Arg, which should arouse concerns.
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Affiliation(s)
- Ruihua Dai
- Department of Environmental Science & Engineering, Fudan University, 2205 Songhu Road, Shanghai 200438, PR China
| | - Yanping Zhou
- Department of Environmental Science & Engineering, Fudan University, 2205 Songhu Road, Shanghai 200438, PR China
| | - Yanan Chen
- Department of Environmental Science & Engineering, Fudan University, 2205 Songhu Road, Shanghai 200438, PR China
| | - Xufeng Zhang
- Department of Environmental Science & Engineering, Fudan University, 2205 Songhu Road, Shanghai 200438, PR China
| | - Yangwei Yan
- Department of Environmental Science & Engineering, Fudan University, 2205 Songhu Road, Shanghai 200438, PR China
| | - Dong An
- Department of Environmental Science & Engineering, Fudan University, 2205 Songhu Road, Shanghai 200438, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
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13
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Wang Z, Luo Z, Yan C, Xing B. Impacts of environmental factors on arsenate biotransformation and release in Microcystis aeruginosa using the Taguchi experimental design approach. WATER RESEARCH 2017; 118:167-176. [PMID: 28431349 DOI: 10.1016/j.watres.2017.04.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 03/22/2017] [Accepted: 04/09/2017] [Indexed: 06/07/2023]
Abstract
Very limited information is available on how and to what extent environmental factors influence arsenic (As) biotransformation and release in freshwater algae. These factors include concentrations of arsenate (As(V)), dissolved inorganic nitrogen (N), phosphate (P), and ambient pH. This study conducted a series of experiments using Taguchi methods to determine optimum conditions for As biotransformation. We assessed principal effective factors of As(V), N, P, and pH and determined that As biotransformation and release actuate at 10.0 μM As(V) in dead alga cells, the As efflux ratio and organic As efflux content actuate at 1.0 mg/L P, algal growth and intracellular arsenite (As(III)) content actuate at 10.0 mg/L N, and the total sum of As(III) efflux from dead alga cells actuates at a pH level of 10. Moreover, N is the critical component for As(V) biotransformation in M. aeruginosa, specifically for As(III) transformation, because N can accelerate algal growth, subsequently improving As(III) accumulation and its efflux, which results in an As(V) to As(III) reduction. Furthermore, low P concentrations in combination with high N concentrations promote As accumulation. Following As(V), P was the primary impacting factor for As accumulation. In addition, small amounts of As accumulation under low concentrations of As and high P were securely stored in living algal cells and were easily released after cell death. Results from this study will help to assess practical applications and the overall control of key environmental factors, particularly those associated with algal bioremediation in As polluted water.
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Affiliation(s)
- Zhenhong Wang
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; School of Chemistry and Environment, Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou, 363000, China; Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA, 01003, United States
| | - Zhuanxi Luo
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA, 01003, United States
| | - Changzhou Yan
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
| | - Baoshan Xing
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA, 01003, United States
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14
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Microcystin Biosynthesis and mcyA Expression in Geographically Distinct Microcystis Strains under Different Nitrogen, Phosphorus, and Boron Regimes. BIOMED RESEARCH INTERNATIONAL 2016; 2016:5985987. [PMID: 27803926 PMCID: PMC5075592 DOI: 10.1155/2016/5985987] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 09/01/2016] [Indexed: 02/04/2023]
Abstract
Roles of nutrients and other environmental variables in development of cyanobacterial bloom and its toxicity are complex and not well understood. We have monitored the photoautotrophic growth, total microcystin concentration, and microcystins synthetase gene (mcyA) expression in lab-grown strains of Microcystis NIES 843 (reference strain), KW (Wangsong Reservoir, South Korea), and Durgakund (Varanasi, India) under different nutrient regimes (nitrogen, phosphorus, and boron). Higher level of nitrogen and boron resulted in increased growth (avg. 5 and 6.5 Chl a mg/L, resp.), total microcystin concentrations (avg. 1.185 and 7.153 mg/L, resp.), and mcyA transcript but its expression was not directly correlated with total microcystin concentrations in the target strains. Interestingly, Durgakund strain had much lower microcystin content and lacked microcystin-YR variant over NIES 843 and KW. It is inferred that microcystin concentration and its variants are strain specific. We have also examined the heterotrophic bacteria associated with cyanobacterial bloom in Durgakund Pond and Wangsong Reservoir which were found to be enriched in Alpha-, Beta-, and Gammaproteobacteria and that could influence the bloom dynamics.
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Zhou Q, Li F, Ge F, Liu N, Kuang Y. Nutrient removal by Chlorella vulgaris F1068 under cetyltrimethyl ammonium bromide induced hormesis. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:19450-19460. [PMID: 27381355 DOI: 10.1007/s11356-016-6999-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 05/27/2016] [Indexed: 06/06/2023]
Abstract
Toxicants are generally harmful to biotechnology in wastewater treatment. However, trace toxicant can induce microbial hormesis, but to date, it is still unknown how this phenomenon affects nutrient removal during municipal wastewater treatment process. Therefore, this study focused on the effects of hormesis induced by cetyltrimethyl ammonium bromide (CTAB), a representative quaternary ammonium cationic surfactant, on nutrient removal by Chlorella vulgaris F1068. Results showed that when the concentration of CTAB was less than 10 ng/L, the cellular components chlorophyll a, proteins, polysaccharides, and total lipids increased by 10.11, 58.17, 38.78, and 11.87 %, respectively, and some enzymes in nutrient metabolism of algal cells, such as glutamine synthetase (GS), acid phosphatase (ACP), H(+)-ATPase, and esterase, were also enhanced. As a result, the removal efficiencies of ammonia nitrogen (NH4 (+)) and total phosphorus (TP) increased by 14.66 and 8.51 %, respectively, compared to the control during a 7-day test period. The underlying mechanism was mainly due to an enhanced photosynthetic activity of C. vulgaris F1068 indicated by the increase in chlorophyll fluorescence parameters (the value of Fv/Fm, ΦII, Fv/Fo, and rETR increased by 12.99, 7.56, 25.59, and 8.11 %, respectively) and adenylate energy charge (AEC) (from 0.68 to 0.72). These results suggest that hormesis induced by trace toxicants could enhance the nutrient removal, which would be further considered in the design of municipal wastewater treatment processes. Graphical abstract The schematic mechanism of C. vulgaris F1068 under CTAB induced hormesis. Green arrows ( ) represent the increase and the red arrow ( ) represents the decrease.
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Affiliation(s)
| | - Feng Li
- Xiangtan University, Xiangtan, Hunan, China
| | - Fei Ge
- Xiangtan University, Xiangtan, Hunan, China.
| | - Na Liu
- Xiangtan University, Xiangtan, Hunan, China
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16
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Wang C, Wang X, Wang P, Chen B, Hou J, Qian J, Yang Y. Effects of iron on growth, antioxidant enzyme activity, bound extracellular polymeric substances and microcystin production of Microcystis aeruginosa FACHB-905. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2016; 132:231-239. [PMID: 27337497 DOI: 10.1016/j.ecoenv.2016.06.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 06/07/2016] [Accepted: 06/07/2016] [Indexed: 06/06/2023]
Abstract
Toxic cyanobacterial blooms have occurred in various water bodies during recent decades and made serious health hazards to plants, animals and humans. Iron is an important micronutrient for algal growth and recently, the concentration of which has increased remarkably in freshwaters. In this paper, the cyanobacterium Microcystis aeruginosa FACHB-905 was cultivated under non-iron (0μM), iron-limited (10μM) and iron-replete (100μM) conditions to investigate the effects of iron on growth, antioxidant enzyme activity, EPS and microcystin production. The results showed that algal cell density and chlorophyll-a content were maximal at the highest iron concentration. Antioxidant enzymes activity increased notably under all three conditions in the early stage of experiment, of which the SOD activity recovered soon from oxidative stress in 10μM group. The productions of some protein-like substances and humic acid-like substances of bound EPS were inhibited in iron-containing groups in the early stage of experiment while promoted after the adaptation period of Microcystis aeruginosa. Iron addition is a factor affecting the formation of cyanobacterial blooms through its impact on the content of LB-EPS and the composition of TB-EPS. The intracellular MC-LR concentration and the productivity potential of MC-LR were the lowest in 0μM group and highest in 10μM group. No obvious extracellular release of MC-LR was observed during the cultivation time. Therefore, iron addition can promote the physiological activities of M. aeruginosa, but a greater harm could be brought into environment under iron-limited (10μM) condition than under iron-replete (100μM) condition.
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Affiliation(s)
- Chao Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, No. 1 Xikang Road, Nanjing 210098, China
| | - Xun Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, No. 1 Xikang Road, Nanjing 210098, China
| | - Peifang Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, No. 1 Xikang Road, Nanjing 210098, China.
| | - Bin Chen
- School of Environment, Beijing Normal University, No. 19 Xinjiekouwai Street, Beijing 100875, China
| | - Jun Hou
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, No. 1 Xikang Road, Nanjing 210098, China
| | - Jin Qian
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, No. 1 Xikang Road, Nanjing 210098, China
| | - Yangyang Yang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, No. 1 Xikang Road, Nanjing 210098, China
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Alexova R, Dang TC, Fujii M, Raftery MJ, Waite TD, Ferrari BC, Neilan BA. Specific global responses to N and Fe nutrition in toxic and non-toxicMicrocystis aeruginosa. Environ Microbiol 2015; 18:401-13. [DOI: 10.1111/1462-2920.12958] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 06/05/2015] [Accepted: 06/15/2015] [Indexed: 01/03/2023]
Affiliation(s)
- Ralitza Alexova
- School of Biotechnology and Biomolecular Sciences; University of New South Wales; Sydney NSW 2052 Australia
| | - The Cuong Dang
- School of Civil and Environmental Engineering; University of New South Wales; Sydney NSW 2052 Australia
| | - Manabu Fujii
- School of Civil and Environmental Engineering; University of New South Wales; Sydney NSW 2052 Australia
- Department of Civil Engineering; Tokyo Institute of Technology; 2-12-1-M1-4 Ookayama Tokyo 152-8552 Japan
| | - Mark J. Raftery
- Bioanalytical Mass Spectrometry Facility; University of New South Wales; Sydney NSW 2052 Australia
| | - T. David Waite
- School of Civil and Environmental Engineering; University of New South Wales; Sydney NSW 2052 Australia
| | - Belinda C. Ferrari
- School of Biotechnology and Biomolecular Sciences; University of New South Wales; Sydney NSW 2052 Australia
- Australian Centre for Astrobiology; University of New South Wales; Sydney NSW 2052 Australia
| | - Brett A. Neilan
- School of Biotechnology and Biomolecular Sciences; University of New South Wales; Sydney NSW 2052 Australia
- Australian Centre for Astrobiology; University of New South Wales; Sydney NSW 2052 Australia
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18
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Wu X, Yan Y, Wang P, Ni L, Gao J, Dai R. Effect of urea on growth and microcystins production of Microcystis aeruginosa. BIORESOURCE TECHNOLOGY 2015; 181:72-77. [PMID: 25638406 DOI: 10.1016/j.biortech.2015.01.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 01/07/2015] [Accepted: 01/09/2015] [Indexed: 06/04/2023]
Abstract
The effects of urea on the growth and toxin content of Microcystis aeruginosa isolated from Dianchi Lake in China were investigated. Experiments were carried out in lab using (15)N isotopic technique to characterize urea-N biosynthesis to microcystins. High urea concentration (3.6 mmol-N L(-1)) would restrict the growth of M.aeruginosa and the production of microcystin-LR, while low urea concentration (0.4-1.4 mmol-N L(-1)) would promote the growth of M.aeruginosa and the production of microcystin-LR. The (15)N labeling experiment further demonstrated that there existed selectivity when M.aeruginosa assimilated urea to form its structure. The majority of M.aeruginosa assimilated 1 urea molecule at first which was biosynthesized into the Ala or Leu residue. On day 18, The m/z=1004 parent ion assimilated 9 (15)N except that the Mdha residue did not assimilate any urea-(15)N. The results give deeper insight to the biosynthesis of urea into microcystins.
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Affiliation(s)
- Xuanhao Wu
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Yangwei Yan
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Pinfei Wang
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Lanqi Ni
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Jiayi Gao
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Ruihua Dai
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
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19
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Yan Y, Dai R, Liu Y, Gao J, Wu X. Comparative effects of inorganic and organic nitrogen on the growth and microcystin production of Microcystis aeruginosa. World J Microbiol Biotechnol 2015; 31:763-72. [PMID: 25726035 DOI: 10.1007/s11274-015-1829-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 02/21/2015] [Indexed: 11/26/2022]
Abstract
Nitrogen causes the frequent occurrence of harmful algal blooms and possible microcystin production. The effects of ammonia and alanine (Ala) on the growth and microcystin production of Microcystis aeruginosa were investigated using an isotope tracer ((15)N). The results indicated that Ala was directly used by M. aeruginosa and contributed to biomass formation amounting to 2.1 × 10(7) cells mL(-1) on day 48, compared with only 6.2 × 10(6) cells mL(-1) from ammonia alone. Microcystin-LR production with Ala was less than that of ammonia, which peaked at 50.2 fg cell(-1) on day 6. Liquid chromatographic analysis with tandem mass spectrometry of (15)N-microcystin-LR suggested that (15)N from ammonia was probably synthesized into the arginine residue. By contrast, (15)N from Ala was assimilated into the Ala, leucine, the iso-linked (2R,3S)-3-methylaspartic acid, arginine, and certain unusual C20 amino acid residues. The results represent the forward steps in the determination of the nitrogen forms that fuel toxin production and blooms.
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Affiliation(s)
- YangWei Yan
- Department of Environmental Science and Engineering, Fudan University, 220 Handan Road, Shanghai, 200433, China,
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20
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Zheng S, Jing G, Wang X, Ouyang Q, Jia L, Tao N. Citral exerts its antifungal activity against Penicillium digitatum by affecting the mitochondrial morphology and function. Food Chem 2015; 178:76-81. [PMID: 25704686 DOI: 10.1016/j.foodchem.2015.01.077] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 01/09/2015] [Accepted: 01/14/2015] [Indexed: 11/17/2022]
Abstract
This work investigated the effect of citral on the mitochondrial morphology and function of Penicillium digitatum. Citral at concentrations of 2.0 or 4.0 μL/mL strongly damaged mitochondria of test pathogen by causing the loss of matrix and increase of irregular mitochondria. The deformation extent of the mitochondria of P. digitatum enhanced with increasing concentrations of citral, as evidenced by a decrease in intracellular ATP content and an increase in extracellular ATP content of P. digitatum cells. Oxygen consumption showed that citral resulted in an inhibition in the tricarboxylic acid cycle (TCA) pathway of P. digitatum cells, induced a decrease in activities of citrate synthetase, isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, succinodehydrogenase and the content of citric acid, while enhancing the activity of malic dehydrogenase in P. digitatum cells. Our present results indicated that citral could damage the mitochondrial membrane permeability and disrupt the TCA pathway of P. digitatum.
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Affiliation(s)
- Shiju Zheng
- School of Chemical Engineering, Xiangtan University, Xiangtan 411105, PR China
| | - Guoxing Jing
- School of Chemical Engineering, Xiangtan University, Xiangtan 411105, PR China.
| | - Xiao Wang
- School of Chemical Engineering, Xiangtan University, Xiangtan 411105, PR China
| | - Qiuli Ouyang
- School of Chemical Engineering, Xiangtan University, Xiangtan 411105, PR China
| | - Lei Jia
- School of Chemical Engineering, Xiangtan University, Xiangtan 411105, PR China
| | - Nengguo Tao
- School of Chemical Engineering, Xiangtan University, Xiangtan 411105, PR China.
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21
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De la Fuente IM, Cortés JM, Valero E, Desroches M, Rodrigues S, Malaina I, Martínez L. On the dynamics of the adenylate energy system: homeorhesis vs homeostasis. PLoS One 2014; 9:e108676. [PMID: 25303477 PMCID: PMC4193753 DOI: 10.1371/journal.pone.0108676] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 09/03/2014] [Indexed: 11/20/2022] Open
Abstract
Biochemical energy is the fundamental element that maintains both the adequate turnover of the biomolecular structures and the functional metabolic viability of unicellular organisms. The levels of ATP, ADP and AMP reflect roughly the energetic status of the cell, and a precise ratio relating them was proposed by Atkinson as the adenylate energy charge (AEC). Under growth-phase conditions, cells maintain the AEC within narrow physiological values, despite extremely large fluctuations in the adenine nucleotides concentration. Intensive experimental studies have shown that these AEC values are preserved in a wide variety of organisms, both eukaryotes and prokaryotes. Here, to understand some of the functional elements involved in the cellular energy status, we present a computational model conformed by some key essential parts of the adenylate energy system. Specifically, we have considered (I) the main synthesis process of ATP from ADP, (II) the main catalyzed phosphotransfer reaction for interconversion of ATP, ADP and AMP, (III) the enzymatic hydrolysis of ATP yielding ADP, and (IV) the enzymatic hydrolysis of ATP providing AMP. This leads to a dynamic metabolic model (with the form of a delayed differential system) in which the enzymatic rate equations and all the physiological kinetic parameters have been explicitly considered and experimentally tested in vitro. Our central hypothesis is that cells are characterized by changing energy dynamics (homeorhesis). The results show that the AEC presents stable transitions between steady states and periodic oscillations and, in agreement with experimental data these oscillations range within the narrow AEC window. Furthermore, the model shows sustained oscillations in the Gibbs free energy and in the total nucleotide pool. The present study provides a step forward towards the understanding of the fundamental principles and quantitative laws governing the adenylate energy system, which is a fundamental element for unveiling the dynamics of cellular life.
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Affiliation(s)
- Ildefonso M. De la Fuente
- Institute of Parasitology and Biomedicine “López-Neyra”, CSIC, Granada, Spain
- Department of Mathematics, University of the Basque Country UPV/EHU, Leioa, Spain
- Unit of Biophysics (CSIC, UPV/EHU), and Department of Biochemistry and Molecular Biology University of the Basque Country, Bilbao, Spain
- Biocruces Health Research Institute, Hospital Universitario de Cruces, Barakaldo, Spain
| | - Jesús M. Cortés
- Biocruces Health Research Institute, Hospital Universitario de Cruces, Barakaldo, Spain
- Ikerbasque: The Basque Foundation for Science, Bilbao, Basque Country, Spain
| | - Edelmira Valero
- Department of Physical Chemistry, School of Industrial Engineering, University of Castilla-La Mancha, Albacete, Spain
| | | | - Serafim Rodrigues
- School of Computing and Mathematics, University of Plymouth, Plymouth, United Kingdom
| | - Iker Malaina
- Biocruces Health Research Institute, Hospital Universitario de Cruces, Barakaldo, Spain
- Department of Physiology, University of the Basque Country UPV/EHU, Bilbao, Spain
| | - Luis Martínez
- Department of Mathematics, University of the Basque Country UPV/EHU, Leioa, Spain
- Biocruces Health Research Institute, Hospital Universitario de Cruces, Barakaldo, Spain
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22
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Huang W, Bi Y, Hu Z. Effects of fertilizer-urea on growth, photosynthetic activity and microcystins production of Microcystis aeruginosa isolated from Dianchi Lake. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2014; 92:514-519. [PMID: 24515350 DOI: 10.1007/s00128-014-1217-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 01/25/2014] [Indexed: 06/03/2023]
Abstract
Urea is the most frequently applied nitrogen (N) fertilizer in agriculture, while its loss is assumed triggering algal blooms in adjacent water bodies. In this context the present study assessed the growth, photosynthetic activity as well as toxin production of Microcystis aeruginosa at different urea concentrations (0.125, 1.25, 12.5, 250 and 2,500 mg/L) using BG11 (containing 250 mg/L NO3(-)-N) as control. The results showed for all endpoints that M. aeruginosa is capable of using urea as N source: the two highest urea treatments delivered comparable values like the control. Low urea concentrations (0.125 and 1.25 mg/L), which were comparable to environmental urea levels, did not sustainably promote the growth, photosynthesis and toxin production of the test species. While, in certain microenvironments urea might potentially reach the concentrations that may affect M. aeruginosa.
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Affiliation(s)
- Wenmin Huang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, People's Republic of China
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23
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Qian H, Pan X, Chen J, Zhou D, Chen Z, Zhang L, Fu Z. Analyses of gene expression and physiological changes in Microcystis aeruginosa reveal the phytotoxicities of three environmental pollutants. ECOTOXICOLOGY (LONDON, ENGLAND) 2012; 21:847-859. [PMID: 22218976 DOI: 10.1007/s10646-011-0845-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/16/2011] [Indexed: 05/31/2023]
Abstract
When the concentrations of ampicillin (Amp), atrazine (Atr) and cadmium chloride (Cd) reach excessive quantities, they become toxic to aquatic organisms. Due to the acceleration of the industrialization and the intensification of human activities, the incidence and concentrations of these types of pollutants in aquatic systems are increasing. The primary purpose of this study was to evaluate the short-term effects of Amp, Atr and Cd on the physiological indices and gene expression levels in Microcystis aeruginosa. These three pollutants significantly induced antioxidant activity but continuously accelerated the cellular oxidative damage in microalgae, which suggests an imbalance between the oxidant and the antioxidant systems. Amp, Atr and Cd also decreased the transcription of psaB, psbD1 and rbcL; the lowest transcription of these genes was only 38.1, 23.7 and 7% of the control, respectively. These three pollutants affected nitrogen (N) and phosphorous (P) uptake by inhibiting the transcription of N or P absorbing and transporting related genes, and they down regulated the transcription of microcystin-related genes, which caused a decrease of microcystin levels; and the lowest level of microcystin was only 42.4% of the control. Our results suggest that these pollutants may cause pleiotropic effects on algal growth and physiological and biochemical reactions, and they may even affect secondary metabolic processes.
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Affiliation(s)
- Haifeng Qian
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, 310032 Zhejiang, China
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24
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Martins A, Vasconcelos V. Use of qPCR for the study of hepatotoxic cyanobacteria population dynamics. Arch Microbiol 2011; 193:615-27. [PMID: 21735229 DOI: 10.1007/s00203-011-0724-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2011] [Revised: 06/05/2011] [Accepted: 06/14/2011] [Indexed: 11/25/2022]
Abstract
Toxic cyanobacteria blooms are increasingly frequent and object of greater concern due to its ecological and health impacts. One important lack in the toxic cyanobacteria research field is to understand which parameters influence most and how they operate to regulate the overall levels of cyanotoxins in a body of water. MC concentration is believed to be influenced by changes in several seasonal environmental factors that influence the succession of toxic cyanobacteria. In the last years, qPCR (quantitative polymerase chain reaction) has been applied to determine the seasonal and temporal shifts in the proportions of MC-producing and non-MC-producing subpopulations by quantifying both mcy genotypes and total population numbers. We discuss the most prominent and recent studies using qPCR to address hepatotoxic cyanobacteria population dynamics and evaluate how they helped understanding the factors promoting the growth of toxic strains in situ and the succession of hepatotoxin-producing genera in natural populations.
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Affiliation(s)
- António Martins
- CIIMAR/CIMAR, Marine and Environmental Research Centre, Porto University, Rua dos Bragas, Portugal
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25
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Sevilla E, Martin-Luna B, Vela L, Bes MT, Peleato ML, Fillat MF. Microcystin-LR synthesis as response to nitrogen: transcriptional analysis of the mcyD gene in Microcystis aeruginosa PCC7806. ECOTOXICOLOGY (LONDON, ENGLAND) 2010; 19:1167-1173. [PMID: 20532619 DOI: 10.1007/s10646-010-0500-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/07/2010] [Indexed: 05/29/2023]
Abstract
The influence of environmental factors on microcystin production by toxic cyanobacteria has been extensively studied. However, the effect of nitrogen on the synthesis of this toxin remains unclear because of the literature contradictory data. The aim of this work was to determine how nitrate affects the transcriptional response of mcyD gene and the microcystin-LR synthesis in Microcystis aeruginosa PCC 7806. For first time real time RT-PCR has been used to investigate the effect of nitrogen availability. Our results show that, under laboratory conditions, an excess of nitrate triggers Microcystis aeruginosa growth without increasing the synthesis of microcystin-LR per cell. The concentration of microcystin in the cultures correlates with mcyD gene expression, being both parameters independent of nitrate availability. Analysis of the bidirectional promoter mcy unravels that the transcription start points of mcyA and mcyD genes did not change under different nitrate regimes. The effect of nitrate inputs in the development of toxic blooms is primarily due to the increased growth rate and population, not to the induction of the mcy operon.
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Affiliation(s)
- Emma Sevilla
- Departamento de Bioquimica y Biologia Molecular y Celular, Facultad de Ciencias, and BIFI, Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain
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26
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Xiao Y, Liu Y, Wang G, Hao Z, An Y. Simulated microgravity alters growth and microcystin production in Microcystis aeruginosa (cyanophyta). Toxicon 2010; 56:1-7. [DOI: 10.1016/j.toxicon.2010.01.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 12/08/2009] [Accepted: 01/26/2010] [Indexed: 11/27/2022]
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27
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Bougaran G, Bernard O, Sciandra A. Modeling continuous cultures of microalgae colimited by nitrogen and phosphorus. J Theor Biol 2010; 265:443-54. [PMID: 20433853 DOI: 10.1016/j.jtbi.2010.04.018] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Revised: 04/19/2010] [Accepted: 04/19/2010] [Indexed: 12/01/2022]
Abstract
It is well documented that the combination of low nitrogen and phosphorus resources can lead to situations where colimitation of phytoplankton growth arises, yet the underlying mechanisms are not fully understood. Here, we propose a Droop-based model built on the idea that colimitation by nitrogen and phosphorus arises from the uptake of nitrogen. Indeed, since N-porters are active systems, they require energy that could be related to the phosphorus status of the cell. Therefore, we assumed that N uptake is enhanced by the P quota. Our model also accounts for the biological observations that uptake of a nutrient can be down-regulated by its own internal quota, and succeeds in describing the strong contrast for the non-limiting quotas under N-limited and P-limited conditions that was observed on continuous cultures with Selenastrum minutum and with Isochrysis affinis galbana. Our analysis suggests that, regarding the colimitation concept, N and P would be better considered as biochemically dependent rather than biochemically independent nutrients.
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Affiliation(s)
- Gaël Bougaran
- PBA-IFREMER, rue de l'Ile d'Yeu, BP 21105, 44311 Nantes cedex 03, France.
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28
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Gong Y, Song L, Wu X, Xiao B, Fang T, Liu J. Effects of arsenate on microcystin content and leakage of Microcystis strain PCC7806 under various phosphate regimes. ENVIRONMENTAL TOXICOLOGY 2009; 24:87-94. [PMID: 18442067 DOI: 10.1002/tox.20392] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Both arsenic pollution and eutrophication are prominent environmental issues when considering the problem of global water pollution. It is important to reveal the effects of arsenic species on cyanobacterial growth and toxin yields to assess ecological risk of arsenic pollution or at least understand naturally occurring blooms. The sensitivity of cyanobacteria to arsenate has often been linked to the structural similarities of arsenate and phosphate. Thus, we approached the effect of arsenate with concentrations from 10(-8) to 10(-4) M on Microcystis strain PCC7806 under various phosphate regimes. The present study showed that Microcystis strain PCC7806 was arsenate tolerant up to 10(-4) M. And such tolerance was without reference to both content of intra- and extra-cellular phosphate. It seems that arsenate involved the regulation of microcystin synthesis and cellular polyphosphate contributed to microcystin production of Microcystis responding to arsenate, since there was a positive linear correlation of the cellular microcystin quota with the exposure concentration of arsenate when the cells were not preconditioned to phosphate starvation. It is presumed that arsenate could help to actively export microcystins from living Microcystis cells when preconditioned to phosphate starvation and incubated with the medium containing 1 microM phosphate. This study firstly provided evidence that microcystin content and/or release of Microcystis might be impacted by arsenate if it exists in harmful algal blooms.
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Affiliation(s)
- Yan Gong
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, People's Republic of China
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29
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Dai R, Liu H, Qu J, Zhao X, Hou Y. Effects of amino acids on microcystin production of the Microcystis aeruginosa. JOURNAL OF HAZARDOUS MATERIALS 2009; 161:730-736. [PMID: 18486331 DOI: 10.1016/j.jhazmat.2008.04.015] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2007] [Revised: 03/14/2008] [Accepted: 04/05/2008] [Indexed: 05/26/2023]
Abstract
A Microcystis aeruginosa which produced high content of microcystin-LR (MC-LR) but no microcystin-RR (MC-RR) was isolated from Dianchi Lake in China. In the molecular structure of MC-LR, glutamic acid, aspartic acid, leucine, alanine and arginine are the constitutional components which are abundant in natural water. In this paper, effects of six amino acids at their natural concentrations on the growth of the M. aeruginosa and the microcystin (MC) production were studied in batch culture. M. aeruginosa could assimilate alanine, leucine and arginine as sole nitrogen sources for growth and MC production. However, glutamic acid, aspartic acid and lysine could not be assimilated quickly, although they could pass the cell membrane and enter into the cell rapidly. Our experiment demonstrated that the possible reason of such phenomenon was that different amino acids had different effects on the process of metabolism through the free dissolved amino acids within the cells.
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Affiliation(s)
- Ruihua Dai
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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