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Struewing I, Sienkiewicz N, Zhang C, Dugan N, Lu J. Effective Early Treatment of Microcystis Exponential Growth and Microcystin Production with Hydrogen Peroxide and Hydroxyapatite. Toxins (Basel) 2022; 15:3. [PMID: 36668822 PMCID: PMC9864239 DOI: 10.3390/toxins15010003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 12/13/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022] Open
Abstract
Mitigating cyanotoxin production is essential to protecting aquatic ecosystems and public health. However, current harmful cyanobacterial bloom (HCB) control strategies have significant shortcomings. Because predicting HCBs is difficult, current HCB control strategies are employed when heavy HCBs have already occurred. Our pilot study developed an effective HCB prediction approach that is employed before exponential cyanobacterial growth and massive cyanotoxin production can occur. We used a quantitative polymerase chain reaction (qPCR) assay targeting the toxin-encoding gene mcyA to signal the timing of treatment. When control measures were applied at an early growth stage or one week before the exponential growth of Microcystis aeruginosa (predicted by qPCR signals), both hydrogen peroxide (H2O2) and the adsorbent hydroxyapatite (HAP) effectively stopped M. aeruginosa growth and microcystin (MC) production. Treatment with either H2O2 (10 mg·L-1) or HAP (40 µm particles at 2.5 g·L-1) significantly reduced both mcyA gene copies and MC levels compared with the control in a dose-dependent manner. While both treatments reduced MC levels similarly, HAP showed a greater ability to reduce mcyA gene abundance. Under laboratory culture conditions, H2O2 and HAP also prevented MC production when applied at the early stages of the bloom when mcyA gene abundance was below 105 copies·mL-1.
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Affiliation(s)
- Ian Struewing
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, USA
| | - Nathan Sienkiewicz
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, USA
| | - Chiqian Zhang
- Department of Civil and Environmental Engineering, Southern University and A&M College, Baton Rouge, LA 70813, USA
| | - Nicholas Dugan
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, USA
| | - Jingrang Lu
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, USA
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Oh KH, Beak KM, Shin Y, Cho YC. Assessing the microcystins concentration through optimized protein phosphatase inhibition assay in environmental samples. J Microbiol 2022; 60:602-609. [DOI: 10.1007/s12275-022-2020-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/14/2022] [Accepted: 03/15/2022] [Indexed: 11/30/2022]
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Pham TL, Tran THY, Shimizu K, Li Q, Utsumi M. Toxic cyanobacteria and microcystin dynamics in a tropical reservoir: assessing the influence of environmental variables. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:63544-63557. [PMID: 32948940 DOI: 10.1007/s11356-020-10826-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 09/13/2020] [Indexed: 06/11/2023]
Abstract
Toxic cyanobacterial blooms (TCBs) have become a growing concern worldwide. The present study investigated the dynamic of toxic cyanobacteria and microcystin (MC) concentrations in the Tri An Reservoir (TAR), a tropical system in Vietnam, with quantitative real-time polymerase chain reaction (qPCR) and high-performance liquid chromatography (HPLC), respectively. The results of the qPCR quantification revealed that Microcystis was the dominant group and the primary MC producer in the TAR. Potentially toxigenic cyanobacteria varied from 1.2 × 104 to 1.58 × 107 cells/mL, and the mean proportion of toxic Microcystis to that of the total toxic cyanobacteria varied from 21 to 88%. Microcystin concentrations in raw water and sediment samples often peaked during June to October as blooms occurred and varied from 0.27 to 6.59 μg/L and from 1.79 to 544.9 ng/g in wet weight, respectively. The results of this study indicated that conditions favoring Microcystis proliferation lead to the selection of more toxic genotypes. Water temperature and light availability were not driving factor in the formation of TCBs in the TAR. However, the high loads of total nitrogen (TN), phosphate, and total phosphorus (TP) into the water via rainfall runoff in combination with a high total suspended solid (TSS) and decreased water level during the early months of the rainy seasons did lead to a shift in Microcystis blooms and higher proportions of toxic genotypes of Microcystis in the TAR. This research may provide more insight into the occurrence mechanism of TCBs in tropical waters. The strategy to control TCB problems in tropical regions should be focused on these limnological and hydrological parameters, in addition to a reduction in nitrogen and phosphorus loading.
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Affiliation(s)
- Thanh-Luu Pham
- Ho Chi Minh City University of Technology (HUTECH), 475A Dien Bien Phu Street, Ward 25, Binh Thanh District, Ho Chi Minh City, 700000, Vietnam.
- Institute of Tropical Biology, Vietnam Academy of Science and Technology (VAST), 85 Tran Quoc Toan Street, District 3, Ho Chi Minh City, 700000, Vietnam.
| | - Thi Hoang Yen Tran
- Institute of Tropical Biology, Vietnam Academy of Science and Technology (VAST), 85 Tran Quoc Toan Street, District 3, Ho Chi Minh City, 700000, Vietnam
| | - Kazuya Shimizu
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8572, Japan
| | - Qintong Li
- Toyo University, 1-1-1 Izumino, Itakura-machi, Ora-gun, Gunma, 374-0193, Japan
| | - Motoo Utsumi
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8572, Japan
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Ramya M, Kayalvizhi M, Haripriya G, Rathinasabapathi P. Detection of microcystin-producing cyanobacteria in water samples using loop-mediated isothermal amplification targeting mcyB gene. 3 Biotech 2018; 8:378. [PMID: 30148028 DOI: 10.1007/s13205-018-1402-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 08/10/2018] [Indexed: 12/30/2022] Open
Abstract
Microcystin toxin-producing cyanobacteria are known to have harmful effects on humans and animals. We have developed a loop-mediated isothermal amplification (LAMP)-based detection method by targeting the microcystin synthetase B gene (mcyB), the gene responsible for the production of microcystin. The sensitivity of the method was found to be 1 fg per reaction, and it was 1000-fold higher than the conventional PCR. The LAMP method was able to amplify the target gene with a minimum amount of dNTP (0.4 mM), which further reduces the cost of reaction. The improved LAMP assay could detect the presence of the toxin-producing cyanobacteria in water samples within 2 h of time, which demonstrates the rapidness of the method. Freshwater samples were screened using the developed LAMP, and seven water samples collected from lakes and a bird sanctuary tested positive for mcyB gene harboring cyanobacteria, and negative in all other drinking waters. Hence, the developed LAMP could be a possible alternative to the existing molecular methods for screening for microcystin in environmental samples with greater sensitivity.
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Joung SH, Oh HM, You KA. Dynamic variation of toxic and non-toxic Microcystis proportion in the eutrophic Daechung Reservoir in Korea. J Microbiol 2016; 54:543-50. [PMID: 27480634 DOI: 10.1007/s12275-016-6141-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 06/02/2016] [Accepted: 06/15/2016] [Indexed: 10/21/2022]
Abstract
This study was conducted to determine the environmental factors affecting the level of potentially toxic Microcystis. The long-term tendencies of temperature, precipitation, and water quality factors were analyzed to determine the environmental characteristics of the Daechung Reservoir in Korea, and water samples were directly collected to analyze the dynamics of toxic and non-toxic Microcystis at weekly intervals from May to October 2012. Microcystis was the dominant genus during the study period, and it was composed of potentially toxic and non-toxic Microcystis. The fraction of potentially toxic Microcystis ranged from 6.0% to 61.1%. The amount of toxic Microcystis was highly related to the intracellular microcystin concentration (r = 0.760, P < 0.01). Therefore, the fraction of potentially toxic Microcystis is an important concern in Microcystis blooming because the intracellular microcystin concentration may reflect microcystin levels in the water. The prevalence of potentially toxic Microcystis was highly related to water temperature in Daechung Reservoir (r = 0.585, P < 0.01). Thus, temperature increase during Microcystis blooming may lead to more frequent toxic Microcystis blooms in eutrophic water bodies.
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Affiliation(s)
- Seung-Hyun Joung
- Dongjin Engineering Co., LTD., Daegu, 740978, Republic of Korea.
| | - Hee-Mock Oh
- Biochemical and Bioenergy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Republic of Korea
| | - Kyung-A You
- Water Environment Research Department, National Institute of Environment Research, Incheon, 22689, Republic of Korea
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Pacheco ABF, Guedes IA, Azevedo SMFO. Is qPCR a Reliable Indicator of Cyanotoxin Risk in Freshwater? Toxins (Basel) 2016; 8:toxins8060172. [PMID: 27338471 PMCID: PMC4926139 DOI: 10.3390/toxins8060172] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 05/23/2016] [Accepted: 05/24/2016] [Indexed: 01/06/2023] Open
Abstract
The wide distribution of cyanobacteria in aquatic environments leads to the risk of water contamination by cyanotoxins, which generate environmental and public health issues. Measurements of cell densities or pigment contents allow both the early detection of cellular growth and bloom monitoring, but these methods are not sufficiently accurate to predict actual cyanobacterial risk. To quantify cyanotoxins, analytical methods are considered the gold standards, but they are laborious, expensive, time-consuming and available in a limited number of laboratories. In cyanobacterial species with toxic potential, cyanotoxin production is restricted to some strains, and blooms can contain varying proportions of both toxic and non-toxic cells, which are morphologically indistinguishable. The sequencing of cyanobacterial genomes led to the description of gene clusters responsible for cyanotoxin production, which paved the way for the use of these genes as targets for PCR and then quantitative PCR (qPCR). Thus, the quantification of cyanotoxin genes appeared as a new method for estimating the potential toxicity of blooms. This raises a question concerning whether qPCR-based methods would be a reliable indicator of toxin concentration in the environment. Here, we review studies that report the parallel detection of microcystin genes and microcystin concentrations in natural populations and also a smaller number of studies dedicated to cylindrospermopsin and saxitoxin. We discuss the possible issues associated with the contradictory findings reported to date, present methodological limitations and consider the use of qPCR as an indicator of cyanotoxin risk.
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Affiliation(s)
- Ana Beatriz F Pacheco
- Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro 21949-902, Brazil.
| | - Iame A Guedes
- Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro 21949-902, Brazil.
| | - Sandra M F O Azevedo
- Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro 21949-902, Brazil.
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Hu L, Kong R, Xu X. Autumnal increase in proportion of toxic Microcystis
in Lake Taihu depends more on temperature adaptability than on effects of toxigenicity. J Appl Microbiol 2015; 119:744-52. [DOI: 10.1111/jam.12868] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 05/07/2015] [Accepted: 05/29/2015] [Indexed: 11/30/2022]
Affiliation(s)
- L. Hu
- State Key Laboratory of Freshwater Ecology and Biotechnology; Institute of Hydrobiology, Chinese Academy of Sciences; Wuhan Hubei China
| | - R. Kong
- State Key Laboratory of Freshwater Ecology and Biotechnology; Institute of Hydrobiology, Chinese Academy of Sciences; Wuhan Hubei China
| | - X. Xu
- State Key Laboratory of Freshwater Ecology and Biotechnology; Institute of Hydrobiology, Chinese Academy of Sciences; Wuhan Hubei China
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