1
|
Ta M, Wei J, Ye S, Zhang J, Song T, Li M. Investigation of dissolved organic matter's influence on the toxicity of cadmium to the cyanobacterium Microcystis aeruginosa by biochemical and molecular assays. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:94790-94802. [PMID: 37540421 DOI: 10.1007/s11356-023-29000-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 07/22/2023] [Indexed: 08/05/2023]
Abstract
Rapid economic development has increased the accumulation of dissolved organic matter (DOM) and heavy metals in aquatic environments. In addition, Microcystis aeruginosa can cause the outbreak of cyanobacteria bloom and can produce microcystin, which poses a threat to human water safety. Therefore, this study analyzed the biochemical and molecular assays of DOM (0, 1, 3, 5, 8, 10 mg C L-1) extracted from four different sources on the toxicity of cadmium (Cd) to M. aeruginosa. The results showed that the addition of different concentrations of DOM from sediment, biochar, and humic acid alleviated the toxicity of Cd to M. aeruginosa. But the addition of rice hulls DOM at high concentrations (8 and 10 mg L-1) significantly reduced the normal growth and metabolic activities of M. aeruginosa. DOM from four different sources promoted the expression level of microcystin-related gene mcyA and the production of microcystin-leucine-arginine (MC-LR), and mcyA was positively correlated with MC-LR. DOM from biochar, sediment, and humic acid were able to bind Cd through complexation. The results will help to understand the toxic effects of heavy metals on toxic-producing cyanobacteria in the presence of DOM, and provide certain reference for the evaluation of water environmental health.
Collapse
Affiliation(s)
- Mingxiang Ta
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China
- Wuxi Environment Monitoring Center, Wuxi, 214121, Jiangsu, People's Republic of China
| | - Jianan Wei
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China
| | - Sisi Ye
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China
| | - Junyi Zhang
- Wuxi Environment Monitoring Center, Wuxi, 214121, Jiangsu, People's Republic of China
| | - Ting Song
- Wuxi Environment Monitoring Center, Wuxi, 214121, Jiangsu, People's Republic of China
| | - Ming Li
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China.
| |
Collapse
|
2
|
Song Y, Li R, Song W, Tang Y, Sun S, Mao G. Microcystis spp. and phosphorus in aquatic environments: A comprehensive review on their physiological and ecological interactions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 878:163136. [PMID: 37001662 DOI: 10.1016/j.scitotenv.2023.163136] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 03/02/2023] [Accepted: 03/24/2023] [Indexed: 05/13/2023]
Abstract
Cyanobacterial blooms caused by eutrophication have become a major environmental problem in aquatic ecosystems worldwide over the last few decades. Phosphorus is a limiting nutrient that affects the growth of cyanobacteria and plays a role in dynamic changes in algal density and the formation of cyanobacterial blooms. Therefore, identifying the association between phosphorus sources and Microcystis, which is the most representative and harmful cyanobacteria, is essential for building an understanding of the ecological risks of cyanobacterial blooms. However, systematic reviews summarizing the relationships between Microcystis and phosphorus in aquatic environments are rare. Thus, this study provides a comprehensive overview of the physiological and ecological interactions between phosphorus sources and Microcystis in aquatic environments from the following perspectives: (i) the effects of phosphorus source and concentration on Microcystis growth, (ii) the impacts of phosphorus on the environmental behaviors of Microcystis, (iii) mechanisms of phosphorus-related metabolism in Microcystis, and (iv) role of Microcystis in the distribution of phosphorus sources within aquatic environments. In addition, relevant unsolved issues and essential future investigations (e.g., secondary ecological risks) have been highlighted and discussed. This review provides deeper insights into the relationship between phosphorus sources and Microcystis and can serve as a reference for the evaluation, monitoring, and effective control of cyanobacterial blooms.
Collapse
Affiliation(s)
- Yuhao Song
- School of Life Sciences, Qufu Normal University, Qufu 273165, China.
| | - Ruikai Li
- School of Life Sciences, Qufu Normal University, Qufu 273165, China
| | - Wenjia Song
- School of Life Sciences, Qufu Normal University, Qufu 273165, China
| | - Yulu Tang
- School of Life Sciences, Qufu Normal University, Qufu 273165, China
| | - Shuangyan Sun
- School of Life Sciences, Qufu Normal University, Qufu 273165, China
| | - Guannan Mao
- State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| |
Collapse
|
3
|
Zhang Y, Whalen JK, Cai C, Shan K, Zhou H. Harmful cyanobacteria-diatom/dinoflagellate blooms and their cyanotoxins in freshwaters: A nonnegligible chronic health and ecological hazard. WATER RESEARCH 2023; 233:119807. [PMID: 36871382 DOI: 10.1016/j.watres.2023.119807] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 02/06/2023] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
Human and ecological health depends on the vitality of freshwater systems, but these are increasingly threatened by cyanotoxins released from harmful algal blooms (HABs). Periodic cyanotoxin production, although undesirable, may be tolerable when there is enough time for cyanotoxins to degrade and dissipate in the environment, but the year-round presence of these toxins will be a chronic health for humans and ecosystems. The purpose of this critical review is to document the seasonal shifts of algal species and their ecophysiological acclimatation to dynamic environmental conditions. We discuss how these conditions will create successive occurrences of algal blooms and the release of cyanotoxins into freshwater. We first review the most common cyanotoxins, and evaluate the multiple ecological roles and physiological functions of these toxins for algae. Then, the annual recurring patterns HABs are considered in the context of global change, which demonstrates the capacity for algal blooms to shift from seasonal to year-round growth regimes that are driven by abiotic and biotic factors, leading to chronic loading of freshwaters with cyanotoxins. At last, we illustrate the impacts of HABs on the environment by compiling four health issues and four ecology issues emanating from their presence in the that covers atmosphere, aquatic ecosystems and terrestrial ecosystems. Our study highlights the annual patterns of algal blooms, and proposes that a "perfect storm" of events is lurking that will cause the 'seasonal toxicity' to become a full-blown, 'chronic toxicity' in the context of the deterioration of HABs, highlighting a non-negligible chronic health and ecological hazard.
Collapse
Affiliation(s)
- Yanyan Zhang
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China; Department of Natural Resource Science, McGill University, Macdonald Campus, 21,111 Lakeshore Road, Ste-Anne-de Bellevue, QC H9×3V9, Canada; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, China.
| | - Joann K Whalen
- Department of Natural Resource Science, McGill University, Macdonald Campus, 21,111 Lakeshore Road, Ste-Anne-de Bellevue, QC H9×3V9, Canada
| | - Chen Cai
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Kun Shan
- Chongqing Key Laboratory of Big Data and Intelligent Computing, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China, CAS Key Lab on Reservoir Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Hongxu Zhou
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| |
Collapse
|
4
|
Martínez de la Escalera G, Kruk C, Segura AM, Piccini C. Effect of hydrological modification on the potential toxicity of Microcystis aeruginosa complex in Salto Grande reservoir, Uruguay. HARMFUL ALGAE 2023; 123:102403. [PMID: 36894214 DOI: 10.1016/j.hal.2023.102403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 02/02/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
It is widely known that the environmental conditions caused by the construction of reservoirs favor the proliferation of toxic cyanobacteria and the formation of blooms due to the high residence time of the water, low turbidity, temperature regimes, among others. Microcystin-producing cyanobacteria such as those from the Microcystis aeruginosa complex (MAC) are the most frequently found organisms in reservoirs worldwide, being the role of the environment on microcystin production poorly understood. Here, we addressed the community dynamics and potential toxicity of MAC cyanobacteria in a subtropical reservoir (Salto Grande) located in the low Uruguay river. Samples were taken from five different sites (upstream, inside the reservoir and downstream) during contrasting seasons (summer and winter) to analyze: (i) the MAC community structure by amplicon sequencing of the phycocyanin gene spacer, (ii) the genotype diversity of microcystin-producing MAC by high resolution melting analysis of the mcyJ gene, and (iii) the abundance and mcy transcription activity of the microcystin-producing (toxic) fraction. We found that MAC diversity decreased from summer to winter but, despite the observed changes in MAC community structure, the abundance of toxic organisms and the transcription of mcy genes were always higher inside the reservoir, regardless of the season. Two different genotypes of toxic MAC were detected inside the reservoir, one associated with low water temperature (15 °C) and one thriving at high water temperature (31 °C). These findings indicate that the environmental conditions inside the reservoir reduce community diversity while promoting the proliferation of toxic genotypes that actively transcribe mcy genes, whose relative abundance will depend on the water temperature.
Collapse
Affiliation(s)
| | - Carla Kruk
- Facultad de Ciencias, IECA, Universidad de la República, Uruguay; Departamento de Modelización Estadística de Datos e Inteligencia Artificial (MEDIA), CURE-Rocha, Universidad de la República, Uruguay
| | - Angel M Segura
- Departamento de Modelización Estadística de Datos e Inteligencia Artificial (MEDIA), CURE-Rocha, Universidad de la República, Uruguay
| | - Claudia Piccini
- Departamento de Microbiología, Instituto de Investigaciones Biológicas Clemente Estable (IIBCE), Montvideo, Uruguay.
| |
Collapse
|
5
|
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: 43] [Impact Index Per Article: 21.5] [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.
Collapse
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
| |
Collapse
|
6
|
Liu J, Chen L, Zhang X. Current research scenario for biological effect of exogenous factors on microcystin synthesis. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:26190-26201. [PMID: 35089514 DOI: 10.1007/s11356-021-18256-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
In natural water bodies, numerous cyanobacteria have the potential to intracellularly synthesize cyanotoxins, among which microcystin (MC) is the ubiquitous toxin that has been well known to be carcinogenic for hepatocytes. MC synthesis is a complex process, which involves about 10 non-ribosomal proteins encoded by the mcy gene cluster. In the natural environments containing MC-producing cyanobacteria, a variety of external factors can affect the generation of MC by mediating the expression of synthesizing genes. These factors can be generally divided into biotic factors (e.g., daphnia, virioplankton, MC-degrading bacteria, algicidal bacteria) and abiotic factors (e.g., nutrients, physical factors, chemicals, phytochemicals, essential trace elements), which are of great significance to the effective reduction of MC. Furthermore, comparison of MC-synthesizing genes in different cyanobacterial strains was performed, and the related factors affecting MC synthesis were summarized. Then, the problems and gaps regarding the biological effect of exogenous factors on microcystin synthesis were discussed. This review article may provide new ideas for addressing the challenges and bottlenecks of MC management.
Collapse
Affiliation(s)
- Jiahui Liu
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, Changsha, China
| | - Lv Chen
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, Changsha, China
| | - Xian Zhang
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, Changsha, China.
- Hunan Provincial Key Laboratory of Clinical Epidemiology, Central South University, Changsha, China.
| |
Collapse
|
7
|
bte Sukarji NH, He Y, Te SH, Gin KYH. Application of a Mechanistic Model for the Prediction of Microcystin Production by Microcystis in Lab Cultures and Tropical Lake. Toxins (Basel) 2022; 14:103. [PMID: 35202131 PMCID: PMC8875899 DOI: 10.3390/toxins14020103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 01/13/2022] [Accepted: 01/24/2022] [Indexed: 12/04/2022] Open
Abstract
Microcystin is an algal toxin that is commonly found in eutrophic freshwaters throughout the world. Many studies have been conducted to elucidate the factors affecting its production, but few studies have attempted mechanistic models of its production to aid water managers in predicting its occurrence. Here, a mechanistic model was developed based on microcystin production by Microcystis spp. under laboratory culture and ambient field conditions. The model was built on STELLA, a dynamic modelling software, and is based on constitutive cell quota that varies with nitrogen, phosphorus, and temperature. In addition to these factors, varying the decay rate of microcystin according to its proportion in the intracellular and extracellular phase was important for the model's performance. With all these effects, the model predicted most of the observations with a model efficiency that was >0.72 and >0.45 for the lab and field conditions respectively. However, some large discrepancies were observed. These may have arisen from the non-constitutive microcystin production that appear to have a precondition of nitrogen abundance. Another reason for the large root mean square error is that cell quota is affected by factors differently between strains.
Collapse
Affiliation(s)
- Nur Hanisah bte Sukarji
- NUS Environmental Research Institute (NERI), National University of Singapore, Singapore 138602, Singapore; (N.H.b.S.); (S.H.T.)
| | - Yiliang He
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
| | - Shu Harn Te
- NUS Environmental Research Institute (NERI), National University of Singapore, Singapore 138602, Singapore; (N.H.b.S.); (S.H.T.)
| | - Karina Yew-Hoong Gin
- NUS Environmental Research Institute (NERI), National University of Singapore, Singapore 138602, Singapore; (N.H.b.S.); (S.H.T.)
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576, Singapore
| |
Collapse
|
8
|
Tanvir RU, Hu Z, Zhang Y, Lu J. Cyanobacterial community succession and associated cyanotoxin production in hypereutrophic and eutrophic freshwaters. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 290:118056. [PMID: 34488165 PMCID: PMC8547520 DOI: 10.1016/j.envpol.2021.118056] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/01/2021] [Accepted: 08/24/2021] [Indexed: 05/06/2023]
Abstract
Cyanobacterial harmful algal blooms (cyanoHABs) in freshwater bodies are mainly attributed to excess loading of nutrients [nitrogen (N) and phosphorus (P)]. This study provides a comprehensive review of how the existing nutrient (i.e., N and P) conditions and microbial ecological factors affect cyanobacterial community succession and cyanotoxin production in freshwaters. Different eutrophic scenarios (i.e., hypereutrophic vs. eutrophic conditions) in the presence of (i) high levels of N and P, (ii) a relatively high level of P but a low level of N, and (iii) a relatively high level of N but a low level of P, are discussed in association with cyanobacterial community succession and cyanotoxin production. The seasonal cyanobacterial community succession is mostly regulated by temperature in hypereutrophic freshwaters, where both temperature and nitrogen fixation play a critical role in eutrophic freshwaters. While the early cyanoHAB mitigation strategies focus on reducing P from water bodies, many more studies show that both N and P have a profound contribution to cyanobacterial blooms and toxin production. The availability of N often shapes the structure of the cyanobacterial community (e.g., the relative abundance of N2-fixing and non-N2-fixing cyanobacterial genera) and is positively linked to the levels of microcystin. Ecological aspects of cyanotoxin production and release, related functional genes, and corresponding nutrient and environmental conditions are also elucidated. Research perspectives on cyanoHABs and cyanobacterial community succession are discussed and presented with respect to the following: (i) role of internal nutrients and their species, (ii) P- and N-based control vs. solely P-based control of cyanoHABs, and (iii) molecular investigations and prediction of cyanotoxin production.
Collapse
Affiliation(s)
- Rahamat Ullah Tanvir
- Department of Civil and Environmental Engineering, University of Missouri, Columbia, MO, 65211, USA
| | - Zhiqiang Hu
- Department of Civil and Environmental Engineering, University of Missouri, Columbia, MO, 65211, USA
| | - Yanyan Zhang
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM, 88003, USA
| | - Jingrang Lu
- Office of Research and Development, United States Environmental Protection Agency (USEPA), Cincinnati, OH, 45268, USA.
| |
Collapse
|
9
|
Zhou J, Gao L, Lin Y, Pan B, Li M. Micrometer scale polystyrene plastics of varying concentrations and particle sizes inhibit growth and upregulate microcystin-related gene expression in Microcystis aeruginosa. JOURNAL OF HAZARDOUS MATERIALS 2021; 420:126591. [PMID: 34256331 DOI: 10.1016/j.jhazmat.2021.126591] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 06/19/2021] [Accepted: 07/04/2021] [Indexed: 06/13/2023]
Abstract
Microplastics (MPs) are a concerning environmental pollutant due to their adverse effects on aquatic organisms. However, the dose- and size-dependent effects of MPs on toxigenic cyanobacteria have not been extensively studied. Herein, we explored the effects of polystyrene MPs (PS-MPs) of varying particle sizes and concentrations on the growth and physiology of Microcystis aeruginosa. The results showed that exposure to 1 µm PS-MPs at a concentration of 2-10 mg L-1 significantly inhibited the growth of M. aeruginosa in a concentration-dependent manner. After 12 days of exposure, high concentrations of 1 µm PS-MPs (≥ 2 mg L-1) increased levels of reactive oxygen species. Following exposure to 5 mg L-1 PS-MPs of different particle sizes, algal growth was inhibited and oxidative stress was induced by 0.5 and 1 µm PS-MPs. At the molecular level, transcription of the atpB gene was generally downregulated in all PS-MPs treatments, while ftsH and fabZ were upregulated. Exposure to PS-MPs also altered the transcription levels of microcystin-related genes (mcyA and mcyH), causing more microcystin to be produced by M. aeruginosa. The results will be useful for understanding the toxicity of MPs toward toxigenic cyanobacteria, and evaluating the ecological risks of MPs in aquatic environments.
Collapse
Affiliation(s)
- Junyu Zhou
- College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Li Gao
- Institute for Sustainable Industries and Liveable Cities, Victoria University, PO Box 14428, Melbourne, Victoria 8001, Australia
| | - Yuye Lin
- College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Baozhu Pan
- State Key Laboratory of Eco-hydraulic in Northwest Arid Region of China, Xi'an University of Technology, Xi'an 710048, Shaanxi, China
| | - Ming Li
- College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China.
| |
Collapse
|
10
|
Ni L, Wu H, Du C, Li X, Li Y, Xu C, Wang P, Li S, Zhang J, Chen X. Effects of allelochemical artemisinin in Artemisia annua on Microcystis aeruginosa: growth, death mode, and microcystin-LR changes. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:45253-45265. [PMID: 33861424 DOI: 10.1007/s11356-021-13793-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 03/31/2021] [Indexed: 06/12/2023]
Abstract
To investigate the effects of an allelochemical artemisinin extracted from Artemisia annua (A. annua) on cell growth, death mode, and microcystin-LR (MC-LR) changes of Microcystis aeruginosa (M. aeruginosa), a series of morphological and biochemical characteristics were studied. The results showed that artemisinin could inhibit the growth of M. aeruginosa and reduce the content of phycobiliprotein. Under the allelopathy of artemisinin, algae cells deformed due to swelling, which caused cell membranes to rupture and cell contents to leak. FDA/PI double-staining results showed that 15.10-94.90% of algae cells experienced the death mode of necrosis-like. Moreover, there were 8.35-14.50% of algae cells undergoing programmed cell death, but their caspase-3-like protease activity remained unchanged, which may mean that algae cells were not experiencing caspase-dependent apoptosis under artemisinin stress. Attacked by artemisinin directly, both intracellular and extracellular MC-LR increased sharply with the upregulation of mcyB, mcyD, and mcyH. The upregulation multiple of mcyH suggested that M. aeruginosa could accelerate transportation of algal toxin under adverse conditions of artemisinin. Artemisinin not only can inhibit the growth of M. aeruginosa but it also causes the accelerated release and increase of microcystin-LR. These imply that the application of artemisinin should be reconsidered in practical water bodies.
Collapse
Affiliation(s)
- Lixiao Ni
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, MOE, School of Environment, Hohai University, Nanjing, 210098, China
| | - Hanqi Wu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, MOE, School of Environment, Hohai University, Nanjing, 210098, China
| | - Cunhao Du
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, MOE, School of Environment, Hohai University, Nanjing, 210098, China
| | - Xianglan Li
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, MOE, School of Environment, Hohai University, Nanjing, 210098, China
| | - Yan Li
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, MOE, School of Environment, Hohai University, Nanjing, 210098, China
| | - Chu Xu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, MOE, School of Environment, Hohai University, Nanjing, 210098, China
| | - Peifang Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, MOE, School of Environment, Hohai University, Nanjing, 210098, China
| | - Shiyin Li
- School of Environment, Nanjing Normal University, Nanjing, 210097, China.
| | - Jianhua Zhang
- Jiangsu Provincial Water Conservancy Department, Nanjing, 210029, China
| | - Xuqing Chen
- Cyanobacteria Management Office, Wuxi, 214071, China
| |
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
Romanis CS, Pearson LA, Neilan BA. Cyanobacterial blooms in wastewater treatment facilities: Significance and emerging monitoring strategies. J Microbiol Methods 2020; 180:106123. [PMID: 33316292 DOI: 10.1016/j.mimet.2020.106123] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 12/06/2020] [Accepted: 12/08/2020] [Indexed: 12/30/2022]
Abstract
Municipal wastewater treatment facilities (WWTFs) are prone to the proliferation of cyanobacterial species which thrive in stable, nutrient-rich environments. Dense cyanobacterial blooms frequently disrupt treatment processes and the supply of recycled water due to their production of extracellular polymeric substances, which hinder microfiltration, and toxins, which pose a health risk to end-users. A variety of methods are employed by water utilities for the identification and monitoring of cyanobacteria and their toxins in WWTFs, including microscopy, flow cytometry, ELISA, chemoanalytical methods, and more recently, molecular methods. Here we review the literature on the occurrence and significance of cyanobacterial blooms in WWTFs and discuss the pros and cons of the various strategies for monitoring these potentially hazardous events. Particular focus is directed towards next-generation metagenomic sequencing technologies for the development of site-specific cyanobacterial bloom management strategies. Long-term multi-omic observations will enable the identification of indicator species and the development of site-specific bloom dynamics models for the mitigation and management of cyanobacterial blooms in WWTFs. While emerging metagenomic tools could potentially provide deep insight into the diversity and flux of problematic cyanobacterial species in these systems, they should be considered a complement to, rather than a replacement of, quantitative chemoanalytical approaches.
Collapse
Affiliation(s)
- Caitlin S Romanis
- School of Environmental and Life Sciences, University of Newcastle, Newcastle 2308, Australia
| | - Leanne A Pearson
- School of Environmental and Life Sciences, University of Newcastle, Newcastle 2308, Australia
| | - Brett A Neilan
- School of Environmental and Life Sciences, University of Newcastle, Newcastle 2308, Australia.
| |
Collapse
|
13
|
Natumi R, Janssen EML. Cyanopeptide Co-Production Dynamics beyond Mirocystins and Effects of Growth Stages and Nutrient Availability. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:6063-6072. [PMID: 32302105 DOI: 10.1021/acs.est.9b07334] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Intensified cyanobacterial bloom events are of increasing global concern because of adverse effects associated with the release of bioactive compounds, including toxic cyanopeptides. Cyanobacteria can produce a variety of cyanopeptides, yet our knowledge about their abundance and co-production remains limited. We applied a suspect-screening approach, including 700 structurally known cyanopeptides, and identified 11 cyanopeptides in Microcystis aeruginosa and 17 in Dolichospermum flos-aquae. Total cyanopeptide concentrations ranged from high nmol to μmol gdry-1 with slightly higher cell quotas in the mid-exponential growth phase. Relative cyanopeptide profiles were unchanged throughout the growth cycle. We demonstrate that quantification based on microcystin-LR equivalents can introduce an error of up to 6-fold and recommend a class-equivalent approach instead. In M. aeruginosa, rarely studied cyclamides dominated (>80%) over cyanopeptolins and microcystins. While all nutrient reductions caused less growth, only lowering phosphorous and micronutrients reduced cyanopeptide production by M. aeruginosa. Similar trends were observed for D. flos-aquae and only lowering nitrogen decreased cyanopeptide production while the relative abundance of individual cyanopeptides remained stable. The synchronized production of other cyanopeptides along with microcystins emphasizes the need to make them available as reference standards to encourage more studies on their occurrence in blooms, persistence, and potential toxicity.
Collapse
Affiliation(s)
- Regiane Natumi
- Department of Environmental Chemistry, Swiss Federal Institute of Aquatic Science and Technology (Eawag), 8600 Dübendorf, Switzerland
| | - Elisabeth M-L Janssen
- Department of Environmental Chemistry, Swiss Federal Institute of Aquatic Science and Technology (Eawag), 8600 Dübendorf, Switzerland
| |
Collapse
|
14
|
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.
Collapse
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.
| |
Collapse
|
15
|
Wang Z, Zhang Y, Huang S, Peng C, Hao Z, Li D. Nitrogen limitation significantly reduces the competitive advantage of toxic Microcystis at high light conditions. CHEMOSPHERE 2019; 237:124508. [PMID: 31408798 DOI: 10.1016/j.chemosphere.2019.124508] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 07/31/2019] [Accepted: 08/02/2019] [Indexed: 06/10/2023]
Abstract
Microcystis is a notorious cyanobacterial genus due to its rapid growth rate, huge biomass, and producing toxins in some eutrophic freshwater environments. To reveal the regulatory factors of interspecific competition between toxic and non-toxic Microcystis, three dominant Microcystis strains were selected, and their photosynthesis, population dynamics and microcystins (MCYST) production were measured. The results suggested that nitrogen-limitation (N-limitation) had a greater restriction for the growth of toxic Microcystis than that of non-toxic Microcystis, especially when cultured at high light or high temperature based on the weight analysis of key factors. Comparison of photosynthesis showed that low light or N-rich would favor the competitive advantage of toxic Microcystis while high light combined with N-limitation would promote the competitive advantage of non-toxic Microcystis, and these two competitive advantages could be further amplified by temperature increase. Mixed competitive experiments of toxic and non-toxic Microcystis were conducted, and the results of absorption spectrum (A485/A665) and qPCR (real-time quantitative PCR) suggested that the proportion of toxic Microcystis and the half-time of succession process were significantly reduced by 69.4% and 28.4% (p < 0.01) respectively by combining N-limitation with high light intensity than that measured under N-limitation condition. N-limitation led to a significant decrease of MCYST cellular quota in Microcystis biomass, which would be further decreased to a lower level by the high light. Based on above mentioned analysis, to decrease the MCYST production of Microcystis blooms, we should control nutrient, especial nitrogen through pollutant intercepting and increase the light intensity through improving water transparency.
Collapse
Affiliation(s)
- Zhicong Wang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, PR China.
| | - Yun Zhang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.
| | - Shun Huang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.
| | - Chengrong Peng
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, PR China.
| | - Zhixiang Hao
- Tianjin Institute of Water Conservancy Science, Tianjin, 300061, PR China.
| | - Dunhai Li
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, PR China.
| |
Collapse
|
16
|
Huang Y, Pan H, Liu H, Xi Y, Ren D. Characteristics of growth and microcystin production of Microcystis aeruginosa exposed to low concentrations of naphthalene and phenanthrene under different pH values. Toxicon 2019; 169:103-108. [PMID: 31494204 DOI: 10.1016/j.toxicon.2019.09.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 08/22/2019] [Accepted: 09/01/2019] [Indexed: 02/06/2023]
Abstract
Here, Microcystis aeruginosa (M. aeruginosa) was studied to analyze the effects of 0.5 mg L-1 naphthalene and 0.05 mg L-1 phenanthrene on profiles of cell growth, chlorophyll-a content and Microcystin-LR (MC-LR) production at different pH values. The results indicated that for both the naphthalene and phenanthrene treatments, the specific growth rates were higher in pH 10.0 than in either pH 7.0 or pH 5.0. In the presence of low concentrations of naphthalene or phenanthrene, chlorophyll-a in medium increased significantly more in pH 10.0 than pH 5.0. chlorophyll-a in cell was significantly lowered when exposed to naphthalene in both pH 10.0 and pH 7.0, and was higher when exposed to phenanthrene in pH 10.0 than pH 5.0. HPLC analysis revealed that the extracellular MC-LR concentrations in M. aeruginosa exposed to either naphthalene or phenanthrene were lower than in control M. aeruginosa at pH 5.0. The intracellular MC-LR levels in toxic M. aeruginosa cells exposed to naphthalene or phenanthrene were higher than in the controls at pH 10.0. Our study suggests that the MC-LR production of M. aeruginosa was affected by the pH value when low concentrations of either naphthalene or phenanthrene were present in the water. These results indicate that the pH value should not be ignored when evaluating the risk of chemicals that promote MC-LR production in eutrophic waters.
Collapse
Affiliation(s)
- Yingping Huang
- College of Biology & Pharmacy, China Three Gorges University, Yichang, 443002, Hubei, PR China; Farmland Environment Monitoring Engineering Technology Center in Hubei, China Three Gorges University, Yichang, 443002, Hubei, PR China; Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education, China Three Gorges University, Hubei, Yichang, 443002, PR China.
| | - Hongyu Pan
- College of Biology & Pharmacy, China Three Gorges University, Yichang, 443002, Hubei, PR China; Farmland Environment Monitoring Engineering Technology Center in Hubei, China Three Gorges University, Yichang, 443002, Hubei, PR China; Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education, China Three Gorges University, Hubei, Yichang, 443002, PR China
| | - Huigang Liu
- Farmland Environment Monitoring Engineering Technology Center in Hubei, China Three Gorges University, Yichang, 443002, Hubei, PR China; Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education, China Three Gorges University, Hubei, Yichang, 443002, PR China.
| | - Ying Xi
- Farmland Environment Monitoring Engineering Technology Center in Hubei, China Three Gorges University, Yichang, 443002, Hubei, PR China; Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education, China Three Gorges University, Hubei, Yichang, 443002, PR China
| | - Dong Ren
- Farmland Environment Monitoring Engineering Technology Center in Hubei, China Three Gorges University, Yichang, 443002, Hubei, PR China; Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education, China Three Gorges University, Hubei, Yichang, 443002, PR China
| |
Collapse
|
17
|
Hu X, Zhang R, Ye J, Wu X, Zhang Y, Wu C. Monitoring and research of microcystins and environmental factors in a typical artificial freshwater aquaculture pond. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:5921-5933. [PMID: 29235032 DOI: 10.1007/s11356-017-0956-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Accepted: 12/06/2017] [Indexed: 06/07/2023]
Abstract
Freshwater aquaculture ponds are important artificially regulated aquatic ecosystems which provide a large number of freshwater fish products in China. The cyanobacteria bloom and microcystin (MC) pollution caused by anthropogenic eutrophication have attracted much attention due to their toxic effects. To provide an insight into the cyanobacterial problem in the ponds, the environmental parameters and MCs of a typical artificial pond in the Yangtze River Delta region of China were monitored and studied from May to December 2015. During the monitoring period, the ponds were in serious eutrophication with total phosphorus (TP) concentrations between 0.95 and 1.80 μg/L, and total nitrogen (TN) concentrations between 1.1 and 4.86 μg/L. High feed coefficient and high fish stock were the main reasons for the eutrophication. The results showed that the water temperature was the key factor that affected the cyanobacteria blooming in the pond. The chlorophyll a concentration was significantly positively correlated with the cyanobacteria density during the blooming season. MC-LR and MC-RR existed simultaneously and showed a significant positive correlation. The peak concentrations of dissolved MC-LR and MC-RR in the pond water were 40.6 and 4.7 μg/L, respectively, which is considered highly toxic. Free MC-LR and MC-RR were also found in the aquaculture products. MC-LR concentrations in the bighead carp (Aristichthys nobilis) liver and shrimp (Macrobrachium nipponense) muscle were up to 2.64 and 4.17 μg/kg, respectively. MC-RR concentration was up to 1.89 μg/kg in the black carp (Mylopharyngodon piceus) liver. The results implied the potential health risks for citizens and pets caused by current artificial freshwater aquaculture pond systems.
Collapse
Affiliation(s)
- Xiaobin Hu
- School of Life Science, Huzhou University, Huzhou, Zhejiang, 313000, China.
| | - Rongfei Zhang
- School of Life Science, Huzhou University, Huzhou, Zhejiang, 313000, China
| | - Jinyun Ye
- School of Life Science, Huzhou University, Huzhou, Zhejiang, 313000, China
| | - Xiang Wu
- School of Life Science, Huzhou University, Huzhou, Zhejiang, 313000, China
| | - Yixiang Zhang
- School of Life Science, Huzhou University, Huzhou, Zhejiang, 313000, China
| | - Chenglong Wu
- School of Life Science, Huzhou University, Huzhou, Zhejiang, 313000, China
| |
Collapse
|
18
|
Peng G, Lin S, Fan Z, Wang X. Transcriptional and Physiological Responses to Nutrient Loading on Toxin Formation and Photosynthesis in Microcystis Aeruginosa FACHB-905. Toxins (Basel) 2017; 9:toxins9050168. [PMID: 28513574 PMCID: PMC5450716 DOI: 10.3390/toxins9050168] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 05/08/2017] [Accepted: 05/11/2017] [Indexed: 01/15/2023] Open
Abstract
An important goal of understanding harmful algae blooms is to determine how environmental factors affect the growth and toxin formation of toxin-producing species. In this study, we investigated the transcriptional responses of toxin formation gene (mcyB) and key photosynthesis genes (psaB, psbD and rbcL) of Microcystis aeruginosa FACHB-905 in different nutrient loading conditions using real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR). Three physio-biochemical parameters (malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH)) were also evaluated to provide insight into the physiological responses of Microcystis cells. We observed an upregulation of mcyB gene in nutrient-deficient conditions, especially in nitrogen (N) limitation condition, and the transcript abundance declined after the nutrient were resupplied. Differently, high transcription levels were seen in phosphorus (P) deficient treatments for key photosynthesis genes throughout the culture period, while those in N-deficient cells varied with time, suggesting an adaptive regulation of Microsystis cells to nutrient stress. Increased contents of antioxidant enzymes (SOD and GSH) were seen in both N and P-deficient conditions, suggesting the presence of excess amount of free radical generation caused by nutrient stress. The amount of SOD and GSH continued to increase even after the nutrient was reintroduced and a strong correlation was seen between the MDA and enzyme activities, indicating the robust effort of rebalancing the redox system in Microcystis cells. Based on these transcriptional and physiological responses of M. aeruginosa to nutrient loading, these results could provide more insight into Microcystis blooms management and toxin formation regulation.
Collapse
Affiliation(s)
- Guotao Peng
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
- College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China.
| | - Sijie Lin
- College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China.
| | - Zhengqiu Fan
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
| | - Xiangrong Wang
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
| |
Collapse
|
19
|
Scherer PI, Raeder U, Geist J, Zwirglmaier K. Influence of temperature, mixing, and addition of microcystin-LR on microcystin gene expression in Microcystis aeruginosa. Microbiologyopen 2017; 6:e00393. [PMID: 27411372 PMCID: PMC5300888 DOI: 10.1002/mbo3.393] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 06/22/2016] [Accepted: 06/23/2016] [Indexed: 01/01/2023] Open
Abstract
Cyanobacteria, such as the toxin producer Microcystis aeruginosa, are predicted to be favored by global warming both directly, through elevated water temperatures, and indirectly, through factors such as prolonged stratification of waterbodies. M. aeruginosa is able to produce the hepatotoxin microcystin, which causes great concern in freshwater management worldwide. However, little is known about the expression of microcystin synthesis genes in response to climate change-related factors. In this study, a new RT-qPCR assay employing four reference genes (GAPDH, gltA, rpoC1, and rpoD) was developed to assess the expression of two target genes (the microcystin synthesis genes mcyB and mcyD). This assay was used to investigate changes in mcyB and mcyD expression in response to selected environmental factors associated with global warming. A 10°C rise in temperature significantly increased mcyB expression, but not mcyD expression. Neither mixing nor the addition of microcystin-LR (10 μg L-1 or 60 μg L-1 ) significantly altered mcyB and mcyD expression. The expression levels of mcyB and mcyD were correlated but not identical.
Collapse
Affiliation(s)
- Pia I. Scherer
- Aquatic Systems Biology UnitLimnological Research Station IffeldorfDepartment of Ecology and Ecosystem ManagementTechnical University of MunichMunichGermany
| | - Uta Raeder
- Aquatic Systems Biology UnitLimnological Research Station IffeldorfDepartment of Ecology and Ecosystem ManagementTechnical University of MunichMunichGermany
| | - Juergen Geist
- Aquatic Systems Biology UnitLimnological Research Station IffeldorfDepartment of Ecology and Ecosystem ManagementTechnical University of MunichMunichGermany
| | - Katrin Zwirglmaier
- Aquatic Systems Biology UnitLimnological Research Station IffeldorfDepartment of Ecology and Ecosystem ManagementTechnical University of MunichMunichGermany
- Present address: Bundeswehr Institute of MicrobiologyMunichGermany
| |
Collapse
|
20
|
Wang J, Liu Q, Feng J, Lv JP, Xie SL. Effect of high-doses pyrogallol on oxidative damage, transcriptional responses and microcystins synthesis in Microcystis aeruginosa TY001 (Cyanobacteria). ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2016; 134P1:273-279. [PMID: 27643987 DOI: 10.1016/j.ecoenv.2016.09.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 09/06/2016] [Accepted: 09/10/2016] [Indexed: 06/06/2023]
Abstract
Severe eutrophication and harmful cyanobacterial blooms of freshwater ecosystems is a persistent environmental topic in recent decades. Pyrogallol (polyphenol) was confirmed to exhibit one of the most intensive inhibitory effects on the Microcystis aeruginosa. In this study, the expression of genes, release of microcystins (MCs) and antioxidant system of pyrogallol on Microcystis aeruginosa TY001 were investigated. The results revealed that the expression of stress response genes (prx, ftsH, grpE and fabZ) and DNA repair genes (recA and gyrB) were up-regulated. Meanwhile, the antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activity, were increased, and the stress caused lipid peroxidation to occur and malondialdehyde (MDA) levels to change. Unexpectedly, the relative transcript abundance of microcystin synthesis genes (mcyB, mcyD and ntcA) and the contents of microcystins (MCs) significantly increased compared with the control in the culture medium. In conclusion, oxidative damage and DNA damage are the primary mechanisms for the allelopathic effect of pyrogallol on M. aeruginosa TY001.
Collapse
Affiliation(s)
- Jie Wang
- School of Life Science, Shanxi University, Taiyuan 030006, China
| | - Qi Liu
- School of Life Science, Shanxi University, Taiyuan 030006, China
| | - Jia Feng
- School of Life Science, Shanxi University, Taiyuan 030006, China
| | - Jun-Ping Lv
- School of Life Science, Shanxi University, Taiyuan 030006, China
| | - Shu-Lian Xie
- School of Life Science, Shanxi University, Taiyuan 030006, China.
| |
Collapse
|
21
|
Samoudi S, Latour D, Robin J, Sabart M, Misson B, Ait Hammou H, Mouhri K, Loudiki M. Horizontal distribution of the cell abundance and toxicity of Microcystis in a hypereutrophic Moroccan reservoir. CONTEMP PROBL ECOL+ 2016. [DOI: 10.1134/s1995425516050139] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
22
|
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.
Collapse
|
23
|
A review on factors affecting microcystins production by algae in aquatic environments. World J Microbiol Biotechnol 2016; 32:51. [PMID: 26874538 DOI: 10.1007/s11274-015-2003-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 12/16/2015] [Indexed: 10/22/2022]
Abstract
Microcystins, a toxin produced by Microcystis aeruginosa have become a global environmental issue in recent years. As a consequence of eutrophication, microcystins have become widely disseminated in drinking water sources, seriously impairing drinking water quality. This review focuses on the relationship between microcystins synthesis and physical, chemical, and biological environmental factors that are significant in controlling their production. Light intensity and temperature are the more important physical factors, and in many cases, an optimum level for these two factors has been observed. Nitrogen and phosphorus are the key chemical factors causing frequent occurrence of harmful algal blooms and microcystins production. The absorption of nutrients and metabolic activities of algae are affected by different concentrations and forms of nitrogen and phosphorus, leading to variations in microcystins production Metal ions and emerging pollutants are other significant chemical factors, whose comprehensive impact is still being studied. Algae can also interact with biological agents like predators and competitors in aquatic environments, and such interactions are suggested to promote MCs production and release. This review further highlights areas that require further research in order to gain a better understanding of microcystins production. It provides a theoretical basis for the control of microcystins production and releasing into aquatic environments.
Collapse
|
24
|
Liu Y, Chen S, Chen X, Zhang J, Gao B. Interactions between Microcystis aeruginosa and coexisting amoxicillin contaminant at different phosphorus levels. JOURNAL OF HAZARDOUS MATERIALS 2015; 297:83-91. [PMID: 25956638 DOI: 10.1016/j.jhazmat.2015.04.064] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 03/02/2015] [Accepted: 04/22/2015] [Indexed: 06/04/2023]
Abstract
Microcystis aeruginosa was cultured with 0.05-5 mg L(-1) of phosphorus and exposed to 200-500 ng L(-1) of amoxicillin for seven days. Amoxicillin presented no significant effect (p>0.05) on the growth of M. aeruginosa at phosphorus levels of 0.05 and 0.2 mg L(-1), but stimulated algal growth as a hormesis effect at phosphorus levels of 1 and 5 mg L(-1). Phosphorus and amoxicillin affected the contents of chlorophyll-a, adenosine triphosphate (ATP) and malondialdehyde, the expression of psbA and rbcL, as well as the activities of adenosinetriphosphatase and glutathione S-transferase in similar manners, but regulated the production and release of microcystins and the activities of superoxide dismutase and peroxidase in different ways. Increased photosynthesis activity was related with the ATP consumption for the stress response to amoxicillin, and the stress response was enhanced as the phosphorus concentration increased. The biodegradation of amoxicillin by M. aeruginosa increased from 11.5% to 28.2% as the phosphorus concentration increased. Coexisting amoxicillin aggravated M. aeruginosa pollution by increasing cell density and concentration of microcystins, while M. aeruginosa alleviated amoxicillin pollution via biodegradation. The interactions between M. aeruginosa and amoxicillin were significantly regulated by phosphorus (p<0.05) and led to a complicated situation of combined pollution.
Collapse
Affiliation(s)
- Ying Liu
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China.
| | - Shi Chen
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China
| | - Xiao Chen
- Shandong Urban and Rural Planning Design Institute, Jinan 250013, China
| | - Jian Zhang
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China
| | - Baoyu Gao
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China
| |
Collapse
|
25
|
Yang Z, Kong F. UV-B Exposure Affects the Biosynthesis of Microcystin in Toxic Microcystis aeruginosa Cells and Its Degradation in the Extracellular Space. Toxins (Basel) 2015; 7:4238-52. [PMID: 26492272 PMCID: PMC4626732 DOI: 10.3390/toxins7104238] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 10/13/2015] [Accepted: 10/14/2015] [Indexed: 11/16/2022] Open
Abstract
Microcystins (MCs) are cyclic hepatotoxic heptapeptides produced by cyanobacteria that can be toxic to aquatic and terrestrial organisms. MC synthesis and degradation are thought to be influenced by several different physical and environmental parameters. In this study, the effects of different intensities of UV-B radiation on MC biosynthesis in Microcystis cells and on its extracellular degradation were investigated by mRNA analysis and degradation experiments. Exposure to UV-B at intensities of 1.02 and 1.45 W/m2 not only remarkably inhibited the growth of Microcystis, but also led to a decrease in the MC concentration. In addition, mcyD transcription was decreased under the same UV-B intensities. These results demonstrated that the effects of UV-B exposure on the biosynthesis of MCs in Microcystis cells could be attributed to the regulation of mcy gene transcription. Moreover, the MC concentration was decreased significantly after exposure to different intensities of UV-B radiation. Of the three MC variants (MC-LR, -RR and -YR, L, R and Y are abbreviations of leucine, arginine and tyrosine), MC-LR and MC-YR were sensitive to UV-B radiation, whereas MC-RR was not. In summary, our results showed that UV-B radiation had a negative effect on MC production in Microcystis cells and MC persistence in the extracellular space.
Collapse
Affiliation(s)
- Zhen Yang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China.
| | - Fanxiang Kong
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China.
| |
Collapse
|
26
|
Liu Y, Zhang J, Gao B. Cellular and transcriptional responses in Microcystis aeruginosa exposed to two antibiotic contaminants. MICROBIAL ECOLOGY 2015; 69:535-543. [PMID: 25342538 DOI: 10.1007/s00248-014-0515-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 10/08/2014] [Indexed: 06/04/2023]
Abstract
The responses of Microcystis aeruginosa under exposure to spiramycin and amoxicillin were investigated on both cellular and genetic levels through a 7-day exposure test. Algal growth was inhibited by spiramycin while promoted by amoxicillin at test concentrations of 0.6-1.8 μg L(-1), indicating a higher toxicity of spiramycin than amoxicillin. During the whole exposure period, the chlorophyll a content and expression levels of psbA, psaB, and rbcL were significantly inhibited by spiramycin at test concentrations of 1.2 and 1.8 μg L(-1) (p < 0.05) and stimulated by 0.6-1.8 μg L(-1) of amoxicillin (p < 0.05), with respective decreases of up to 26, 75, 72, and 82% compared to the control and respective increases of 20, 70, 135, and 55%. During the 4 to 7 days of exposure, the microcystin-LR content and expression levels of mcyB and grpE were reduced by up to 66, 47, and 72% in spiramycin-treated algal cells, respectively, and stimulated by up to 1.3-, 1.4-, and 1.5-folds in amoxicillin-treated algal cells, respectively. Elevated recA expression was only observed in 1.2 and 1.8 μg L(-1) of spiramycin-treated algal cells, indicating severe DNA damage due to the high toxicity. Target antibiotics were suspected to regulate the growth and microcystin-production in M. aeruginosa via the photosynthesis system.
Collapse
Affiliation(s)
- Ying Liu
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan, 250100, People's Republic of China,
| | | | | |
Collapse
|
27
|
Liu Y, Wang F, Chen X, Zhang J, Gao B. Influence of coexisting spiramycin contaminant on the harm of Microcystis aeruginosa at different nitrogen levels. JOURNAL OF HAZARDOUS MATERIALS 2015; 285:517-524. [PMID: 25559779 DOI: 10.1016/j.jhazmat.2014.11.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 09/26/2014] [Accepted: 11/20/2014] [Indexed: 06/04/2023]
Abstract
The influence of nitrogen on the effects of the antibiotic contaminant spiramycin on Microcystis aeruginosa was studied through a 7-day exposure test. At current contamination levels of 0.5-100 mg L(-1) for nitrogen and 0.1-0.4 μg L(-1) for spiramycin, the two factors significantly interacted with each other (p<0.05) on the synthesis of chlorophyll-a and protein, the production and release of microcystins as well as the expression of ntcA gene and mcyB gene in M. aeruginosa. Nitrogen significantly affected the toxicity of spiramycin on algal growth (p<0.05) via regulation of protein synthesis. The photosynthesis system including chlorophyll-a, the psbA gene, and the rbcL gene participated in stress responses to spiramycin. Coexisting spiramycin contaminant increased the harm of M. aeruginosa by stimulating the production and release of MCs at a nitrogen level of 0.5 mg L(-1), but alleviated M. aeruginosa pollution at higher nitrogen levels of 5-100 mg L(-1) by inhibiting algal growth, the production of microcystins and the expression of ntcA and mcyB. The nitrogen-dependent effects of spiramycin should be considered in the control of M. aeruginosa bloom in the presence of spiramycin.
Collapse
Affiliation(s)
- Ying Liu
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China.
| | - Feng Wang
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China
| | - Xiao Chen
- Shandong Urban and Rural Planning Design Institute, Jinan 250013, China
| | - Jian Zhang
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China
| | - Baoyu Gao
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China
| |
Collapse
|
28
|
Gehringer MM, Wannicke N. Climate change and regulation of hepatotoxin production in Cyanobacteria. FEMS Microbiol Ecol 2014; 88:1-25. [PMID: 24490596 DOI: 10.1111/1574-6941.12291] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 01/20/2014] [Accepted: 01/20/2014] [Indexed: 01/04/2023] Open
Abstract
Harmful, bloom-forming cyanobacteria (CyanoHABs) are occurring with increasing regularity in freshwater and marine ecosystems. The most commonly occurring cyanobacterial toxins are the hepatotoxic microcystin and nodularin. These cyclic hepta- and pentapeptides are synthesised nonribosomally by the gene products of the toxin gene clusters mcy and nda, respectively. Understanding of the regulation of hepatotoxin production is incomplete, although there is strong evidence supporting the roles of iron, light, higher nitrate availability and inorganic carbon in modulating microcystin levels. The majority of these studies have focused on the unicellular freshwater, microcystin-producing strain of Microcystis aeruginosa, with little attention being paid to terrestrial or marine toxin producers. This review intends to investigate the regulation of microcystin and nodularin production in unicellular and filamentous diazotrophic cyanobacteria against the background of changing climate conditions. Special focus is given to diazotrophic filamentous cyanobacteria, for example Nodularia spumigena, capable of regulating their nitrogen levels by actively fixing dinitrogen. By combining data from significant studies, an overall scheme of the regulation of toxin production is presented, focussing specifically on nodularin production in diazotrophs against the background of increasing carbon dioxide concentrations and temperatures envisaged under current climate change models. Furthermore, the risk of sustaining and spreading CyanoHABs in the future ocean is evaluated.
Collapse
Affiliation(s)
- Michelle M Gehringer
- Department of Plant Ecology and Systematics, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | | |
Collapse
|