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Kim W, Park Y, Kim M, Cha Y, Jung J, Jeon CO, Park W. Sustainable control of Microcystis aeruginosa, a harmful cyanobacterium, using Selaginella tamariscina extracts. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 277:116375. [PMID: 38677071 DOI: 10.1016/j.ecoenv.2024.116375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 04/02/2024] [Accepted: 04/20/2024] [Indexed: 04/29/2024]
Abstract
Eco-friendly reagents derived from plants represent a promising strategy to mitigate the occurrence of toxic cyanobacterial blooms. The use of an amentoflavone-containing Selaginella tamariscina extract (STE) markedly decreased the number of Microcystis aeruginosa cells, thus demonstrating significant anti-cyanobacterial activity. In particular, the Microcystis-killing fraction obtained from pulverized S. tamariscina using hot-water-based extraction at temperatures of 40 °C induced cell disruption in both axenic and xenic M. aeruginosa. Liquid chromatographic analysis was also conducted to measure the concentration of amentoflavone in the STE, thus supporting the potential M. aeruginosa-specific killing effects of STE. Bacterial community analysis revealed that STE treatment led to a reduction in the relative abundance of Microcystis species while also increasing the 16S rRNA gene copy number in both xenic M. aeruginosa NIBR18 and cyanobacterial bloom samples isolated from a freshwater environment. Subsequent testing on bacteria, cyanobacteria, and algae isolated from freshwater revealed that STE was not toxic for other taxa. Furthermore, ecotoxicology assessment involving Aliivibrio fischeri, Daphnia magna, and Danio rerio found that high STE doses immobilized D. magna but did not impact the other organisms, while there was no change in the water quality. Overall, due to its effective Microcystis-killing capability and low ecotoxicity, aqueous STE represents a promising practical alternative for the management of Microcystis blooms.
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Affiliation(s)
- Wonjae Kim
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, South Korea
| | - Yerim Park
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, South Korea
| | - Minkyung Kim
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, South Korea
| | - Yeji Cha
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, South Korea
| | - Jaejoon Jung
- Department of Life Science, Chung-Ang University, Seoul 02841, South Korea
| | - Che Ok Jeon
- Department of Life Science, Chung-Ang University, Seoul 02841, South Korea
| | - Woojun Park
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, South Korea.
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Cheng K, Zhao K, Zhang R, Guo J. Progress on control of harmful algae by sustained-release technology of allelochemical: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 918:170364. [PMID: 38307275 DOI: 10.1016/j.scitotenv.2024.170364] [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: 10/20/2023] [Revised: 01/16/2024] [Accepted: 01/20/2024] [Indexed: 02/04/2024]
Abstract
The outbreak of harmful algae blooms caused by water eutrophication seriously jeopardizes the aquatic ecological environment and human health. Therefore, algae control technology has attracted widespread attention between environmental scholars. Allelochemical sustained-release technology which releases the active ingredient to the target medium at a certain rate within the effective time, so that the system maintains a certain concentration, thus prolonging its influence on the target organism. Allelochemical sustained-release technology has become the focus of research due to the characteristics of high efficiency, safety, low-cost, environment friendly and no secondary pollution. This paper reviews the characteristics of allelochemical substances and the status quo of plant extraction, explains the detailed classification of allelochemical sustained-release microspheres (ASRMs) and the application of algae inhibition, summarizes the preparation method of ASRMs, elaborates on the mechanism of algae inhibition of sustained-release technology from the perspective of photosynthesis, cellular enzyme activity, algae cell structure, gene expression, and target site action. Focuses on the summary of the factors influencing the effect of algae inhibition of ASRMs, including particle size of sustained-release microspheres, selection of carrier materials, and the growth stage of algae. The future direction and prospect of algae inhibition by allelochemical sustained-release technology were prospected to provide the scientific basis for water ecological restoration.
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Affiliation(s)
- Kai Cheng
- Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of the Ministry of Education, Key Laboratory of Eco-hydrology and Water Security in Arid and Semi-arid Regions of Ministry of Water Resources, School of Water and Environment, Chang'an University, Xi'an 710054, PR China
| | - Kai Zhao
- Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of the Ministry of Education, Key Laboratory of Eco-hydrology and Water Security in Arid and Semi-arid Regions of Ministry of Water Resources, School of Water and Environment, Chang'an University, Xi'an 710054, PR China
| | - Rong Zhang
- Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of the Ministry of Education, Key Laboratory of Eco-hydrology and Water Security in Arid and Semi-arid Regions of Ministry of Water Resources, School of Water and Environment, Chang'an University, Xi'an 710054, PR China
| | - Jifeng Guo
- Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of the Ministry of Education, Key Laboratory of Eco-hydrology and Water Security in Arid and Semi-arid Regions of Ministry of Water Resources, School of Water and Environment, Chang'an University, Xi'an 710054, PR China.
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Liu X, Sun T, Yang W, Li X, Ding J, Fu X. Meta-analysis to identify inhibition mechanisms for the effects of submerged plants on algae. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 355:120480. [PMID: 38430885 DOI: 10.1016/j.jenvman.2024.120480] [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: 11/14/2023] [Revised: 02/07/2024] [Accepted: 02/20/2024] [Indexed: 03/05/2024]
Abstract
Submerged plants inhibit algae through shading effects, nutrient competition, allelopathy, and combinations of these mechanisms. However, it is unclear which mechanism is dominant, and how the inhibition intensity results from the traits of the plant and algae. In this study, we performed meta-analysis to quantitatively identify the dominant mechanisms, evaluate the relationship between inhibition intensity and the species and functional traits of the submerged plants or algae, and reveal the influences of external environmental factors. We found that allelopathy caused stronger inhibition than the shading effect and nutrient competition and dominated the combined mechanisms. Although the leaf shapes of the submerged plants influenced light availability, this did not change the degree of algae suppression. Algal species, properties (toxic or nontoxic) and external environmental factors (e.g., lab/mesocosm experiments, co-/filtrate/extract culture, presence or absence of interspecific competition) potentially influenced inhibition strength. Cyanobacteria and Bacillariophyta were more strongly inhibited than Chlorophyta, and toxic Cyanobacteria more than non-toxic Cyanobacteria. Algae inhibition by submerged plants was species-dependent. Ceratophyllum, Vallisneria, and Potamogeton strongly inhibited Microcystis, and can potentially prevent or mitigate harmful algal blooms of this species. However, the most common submerged plant species inhibited mixed algae communities to some extent. The results from lab experiments and mesocosm experiments both confirmed the inhibition of algae by submerged plants, but more evidence from mesocosm experiments is needed to elucidate the inhibition mechanism in complex ecosystems. Submerged plants in co-cultures inhibited algae more strongly than in extract and filtrate cultures. Complex interspecific competition may strengthen or weaken algae inhibition, but the response of this inhibition to complex biological mechanisms needs to be further explored. Our meta-analysis provides insights into which mechanisms contributed most to the inhibition effect and a scientific basis for selecting suitable submerged plant species and controlling external conditions to prevent algal blooms in future ecological restoration of lakes.
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Affiliation(s)
- Xinyu Liu
- School of Environment, State Key Laboratory of Water Environment Simulation, Beijing Normal University, Beijing 100875, China
| | - Tao Sun
- School of Environment, State Key Laboratory of Water Environment Simulation, Beijing Normal University, Beijing 100875, China; Yellow River Estuary Wetland Ecosystem Observation and Research Station, Ministry of Education, Dongying, China
| | - Wei Yang
- School of Environment, State Key Laboratory of Water Environment Simulation, Beijing Normal University, Beijing 100875, China; Yellow River Estuary Wetland Ecosystem Observation and Research Station, Ministry of Education, Dongying, China.
| | - Xiaoxiao Li
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, China
| | - Jiewei Ding
- School of Environment, State Key Laboratory of Water Environment Simulation, Beijing Normal University, Beijing 100875, China
| | - Xianting Fu
- School of Environment, State Key Laboratory of Water Environment Simulation, Beijing Normal University, Beijing 100875, China
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Tang B, Zhang L, Salam M, Yang B, He Q, Yang Y, Li H. Revealing the environmental hazard posed by biodegradable microplastics in aquatic ecosystems: An investigation of polylactic acid's effects on Microcystis aeruginosa. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 344:123347. [PMID: 38215868 DOI: 10.1016/j.envpol.2024.123347] [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: 10/20/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 01/14/2024]
Abstract
The influence of petroleum-based microplastics (MPs) on phytoplankton has been extensively studied, while research on the impact of biodegradable MPs, derived from alternative plastics to contest the environmental crisis, remains limited. This study performed a 63 days co-incubation experiment to assess the effect of polylactic acid MPs (PLA-MPs) on the growth, physiology, and carbon utilization of M. aeruginosa and the change in PLA-MPs surface properties. The results showed that despite PLA-MPs induced oxidative stress and caused membrane damage in M. aeruginosa, the presence of PLA-MPs (10, 50, and 200 mg/L) triggered significant increases (p < 0.05) in the density of M. aeruginosa after 63 days. Specifically, the algal densities upon 50 and 200 mg/L PLA-MPs exposure were increased by 20.91% and 36.31% relative to the control, respectively. Meanhwhile, the reduced C/O ratio on PLA-MPs surface and change in PLA-MPs morphological characterization, which is responsible for substantially increase in the aquatic dissolved inorganic carbon concentration during the co-incubation, implying the degradation of PLA-MPs; thus, provided sufficient carbon resources that M. aeruginosa could assimilate. This was in line with the declined intracellular carbonic anhydrase content in M. aeruginosa. This study is the first attempt to uncover the interaction between PLA-MPs and M. aeruginosa, and the finding that their interaction promotes the degrading of PLA-MPs meanwhile favoring M. aeruginosa growth will help elucidate the potential risk of biodegradable MPs in aquatic environment.
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Affiliation(s)
- Bingran Tang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; Aquatic Ecosystems in the Three Gorges Reservoir Region of Chongqing Observation and Research Station, Chongqing, 400044, China
| | - Lixue Zhang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; Aquatic Ecosystems in the Three Gorges Reservoir Region of Chongqing Observation and Research Station, Chongqing, 400044, China
| | - Muhammad Salam
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China
| | - Bing Yang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; Ecological and Environment Monitoring Center of Chongqing, Chongqing, 401147, China
| | - Qiang He
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; Aquatic Ecosystems in the Three Gorges Reservoir Region of Chongqing Observation and Research Station, Chongqing, 400044, China
| | - Yongchuan Yang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; Aquatic Ecosystems in the Three Gorges Reservoir Region of Chongqing Observation and Research Station, Chongqing, 400044, China
| | - Hong Li
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; Aquatic Ecosystems in the Three Gorges Reservoir Region of Chongqing Observation and Research Station, Chongqing, 400044, China.
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Wijesinghe A, Senavirathna MDHJ, Fujino T. Egeria densa organic extracts: an eco-friendly approach to suppress Microcystis aeruginosa growth through allelopathy. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2023; 88:2955-2973. [PMID: 38096081 PMCID: wst_2023_387 DOI: 10.2166/wst.2023.387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Macrophytes play a significant role in shaping plankton communities by shading, controlling water turbulence, and nutrient availability, while also producing allelochemicals causing varying effects on different organisms. Many researchers have shown that when live macrophytes are present, they inhibit cyanobacteria. However, their widespread use is often limited due to numerous concerns, including invasive characteristics. This study focused on the applicability of Egeria densa extracts to suppress Microcystis aeruginosa. We employed pure water and dimethyl sulfoxide, to obtain compounds from E. densa. The results revealed that E. densa aqueous extracts stimulated M. aeruginosa growth, whereas organic extracts exhibited suppression. Specifically, at low concentrations of organics extracts (0.5 and 1 g/L), after day 4, the growth inhibition was confirmed by significantly higher (p < 0.05) stress levels shown in cells treated with low concentrations. The highest inhibition rate of 32% was observed at 0.5 g/L. However, high concentrations of organic extracts (3 and 6 g/L), showed increased growth compared with control. These results suggest that high concentrations of organic extracts from E. densa potentially suppress allelochemical-induced M. aeruginosa inhibition due to high nutrient availability. In comparison with an aqueous solvent, the use of organic solvent seems to be more effective in efficiently extracting allelochemicals from E. densa.
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Affiliation(s)
- Ashika Wijesinghe
- Department of Environmental Science and Technology, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan E-mail: ;
| | | | - Takeshi Fujino
- Department of Environmental Science and Technology, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
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Wang T, Liu H. Aquatic plant allelochemicals inhibit the growth of microalgae and cyanobacteria in aquatic environments. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:105084-105098. [PMID: 37740161 DOI: 10.1007/s11356-023-29994-5] [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: 04/04/2023] [Accepted: 09/16/2023] [Indexed: 09/24/2023]
Abstract
Excess nitrogen and phosphorus nutrients in the aquatic environment result in the growth of algal cells and water eutrophication, which adversely affect the aquatic environment and human health. Therefore, discovering a safe and efficient algae suppression method is necessary to ensure the ecological safety of water. Recently, the allelopathic effects of aquatic plants on algae have attracted extensive attention from researchers. This review demonstrates the current research hotspot of allelopathic algal inhibition in aquatic plants and lists the common aquatic plant species and allelochemicals. In addition, the inhibition mechanism of allelochemicals from aquatic plants on algae is systematically discussed. Moreover, the key factors affecting the inhibition of allelopathy in algae, such as pH, temperature, algal cell density, and concentration of allelochemicals, are summarized. The present utilization modes of allelochemicals on algae are also presented. Finally, the problems existing in the study of allelopathic algal inhibition of aquatic plants are highlighted, and suggestions for further research are proposed.
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Affiliation(s)
- Tiantian Wang
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 21500, China
| | - Haicheng Liu
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 21500, China.
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Gil CS, Eom SH. Two different anti-algal control mechanisms in Microcystis aeruginosa induced by robinin or tannin rich plants. CHEMOSPHERE 2023; 323:138202. [PMID: 36849021 DOI: 10.1016/j.chemosphere.2023.138202] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/05/2023] [Accepted: 02/20/2023] [Indexed: 06/18/2023]
Abstract
Phytochemical is considered an alternative method for cyanobacterial bloom control in aquatic environments. When cyanobacteria are treated with anti-algal materials produced from plant tissues, they tend to exhibit growth inhibition or necrosis of cells. These different anti-algal responses have not been well discussed, and thus, the modes of anti-algal action in cyanobacteria remain obscure. In this study, transcriptomic and biochemical researches were conducted to understand the mechanisms of cyanobacterial growth inhibition and necrosis in harmful cyanobacterial cells exposed to allelopathic materials. The cyanobacteria Microcystis aeruginosa was treated with aqueous extracts of walnut husk, rose leaf, and kudzu leaf. Walnut husk and rose leaf extracts induced mortality of cyanobacterial population with cell necrosis, whereas kudzu leaf extract exhibited poorly grown cells with shrunk size. Through RNA sequencing, it was revealed that the necrotic extracts significantly downregulated critical genes in enzymatic chain reactions for carbohydrate assembly in the carbon fixation cycle and peptidoglycan synthesis. Compared to the necrotic extract treatment, expression of several genes related to DNA repair, carbon fixation, and cell reproduction was less interrupted by the kudzu leaf extract. Biochemical analysis of cyanobacterial regrowth was performed using gallotannin and robinin. Gallotannin was identified as the major anti-algal compound in walnut husk and rose leaf affecting cyanobacterial necrosis, whereas robinin, which is the typical chemical in kudzu leaf, was associated with growth inhibition of cyanobacterial cells. These combinational studies using RNA sequencing and regrowth assays provided evidence supporting the allelopathic effects of plant-derived materials on cyanobacterial control. Furthermore, our findings suggest novel algicidal scenarios with different responses in the cyanobacterial cells depending on the type of anti-algal compounds.
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Affiliation(s)
- Chan Saem Gil
- Department of Smart Farm Science, College of Life Sciences, Kyung Hee University, Yongin, 17104, South Korea.
| | - Seok Hyun Eom
- Department of Smart Farm Science, College of Life Sciences, Kyung Hee University, Yongin, 17104, South Korea.
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Zhao Q, Jiang R, Shi Y, Shen A, He P, Shao L. Allelopathic Inhibition and Mechanism of Quercetin on Microcystis aeruginosa. PLANTS (BASEL, SWITZERLAND) 2023; 12:plants12091808. [PMID: 37176865 PMCID: PMC10181490 DOI: 10.3390/plants12091808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 04/18/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023]
Abstract
The utilization of allelochemicals to inhibit algal overgrowth is a promising approach for controlling harmful algal blooms (HABs). Quercetin has been found to have an allelopathic effect on algae. However, its responsive mechanism needs to be better understood. In the present study, the inhibitory effects of different quercetin concentrations on M. aeruginosa were evaluated, and the inhibition mechanisms were explored. The results demonstrated that quercetin significantly inhibited M. aeruginosa growth, and the inhibitory effect was concentration-dependent. The inhibition rate of 40 mg L-1 quercetin on algal density reached 90.79% after 96 h treatment. The concentration of chlorophyll-a (chl-a) in treatment groups with quercetin concentrations of 10, 20, and 40 mg L-1 decreased by 59.74%, 74.77%, and 80.66% at 96 h, respectively. Furthermore, quercetin affects photosynthesis and damages the cell membrane, respiratory system, and enzyme system. All photosynthetic fluorescence parameters, including the maximum photochemical quantum yield (Fv/Fm), the actual photochemical quantum yield (YII), the maximum relative electron transfer rate (rETRmax), and light use efficiency (α), exhibited a downtrend after exposure. After treatment with 20 mg L-1 quercetin, the nucleic acid and protein content in the algal solution increased, and the respiration rate of algae decreased significantly. Additionally, superoxide dismutase (SOD) activities significantly increased as a response to oxidative stress. In comparison, the activities of ribulose 1,5-biphosphate carboxylase (Rubisco) and phosphoenolpyruvate carboxylase (PEPC) decreased significantly. These results revealed that quercetin could inhibit M. aeruginosa by affecting its photosynthesis, respiration, cell membrane, and enzymic system. These results are promising for controlling M. aeruginosa effectively.
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Affiliation(s)
- Qianming Zhao
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
| | - Ruitong Jiang
- Shanghai Engineering Research Center of River and Lake Biochain Construction and Resource Utilization, Shanghai 201702, China
| | - Yuxin Shi
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
| | - Anglu Shen
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
| | - Peimin He
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
- Marine Scientific Research Institute, Shanghai Ocean University, Shanghai 201306, China
- Water Environment & Ecology Engineering Research Center of Shanghai Institution of Higher Education, Shanghai 201306, China
| | - Liu Shao
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
- Marine Scientific Research Institute, Shanghai Ocean University, Shanghai 201306, China
- Water Environment & Ecology Engineering Research Center of Shanghai Institution of Higher Education, Shanghai 201306, China
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Allelopathic inhibition effects and mechanism of phenolic acids to Microcystis aeruginosa. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:45388-45397. [PMID: 36705822 DOI: 10.1007/s11356-022-24992-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 12/22/2022] [Indexed: 01/28/2023]
Abstract
Allelochemicals are essential agents for the biological control of harmful blooms. It is crucial to identify efficient algal suppressors and understand their mechanisms. This study reports the inhibition of Microcystis aeruginosa growth by 6 phenolic acids derived from plants' secondary metabolites. The inhibitory effect of phenolic acids was significantly influenced by exposure dose and phenolic acid species. Caffeic acid has the most efficient algal inhibition ability (96 h-EC50 of 5.8 mg/L). In contrast, the other 5 analogs (cinnamic acid, p-coumaric acid, 3-hydroxycinnamic acid, ferulic acid, and isoferulic acid) showed a weak inhibition effect or promotion effect with the exposure dose of 5-100 mg/L. ROS and chlorophyll a content tests combined with metabolomics analysis revealed that caffeic acid could induce the ROS accumulation of M. aeruginosa. They mainly disturbed nucleotide, amino acid, and fatty acid metabolism, leading to the downregulation of most metabolites, including toxins of microcystin LR and cyanopeptolin A, and the precursors of some unpleasant terpenoids. It has been suggested that caffeic acid is an effective agent for controlling M. aeruginosa blooms.
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Zhang T, Shi M, Yan H, Li C. Effects of Salicylic Acid on Heavy Metal Resistance in Eukaryotic Algae and Its Mechanisms. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:13415. [PMID: 36293995 PMCID: PMC9603326 DOI: 10.3390/ijerph192013415] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 10/09/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
Abstract
Heavy metal pollution and water eutrophication are still the main issues to be solved in the environmental field. To find a biological control method for Cd2+-contaminated water or combined eutrophication and Cd2+ pollution water, the effects of salicylic acid on heavy metal Cd2+ resistance in eukaryotic algae Scenedesmus obliquus and Chlorella pyrenoidosa and its mechanisms were studied. The results showed that the inhibition rates of 3.0 mg/L Cd2+ stress group at 96 h were 67.0% on S. obliquus and 61.4% on C. pyrenoidosa and their uptake of Cd2+ was 0.31 mg/g and 0.35 mg/g, respectively. When adding the different concentrations of salicylic acid while stressed by 3.0 mg/L Cd2+, the hormesis phenomenon of low dose stimulation and high dose inhibition could be seen, and the inhibition rates of 30 mg/L~90 mg/L salicylic acid addition groups were significantly lower than those of the Cd2+ stress group alone, which were statistically significant (p < 0.05) and the absorption of Cd2+ was dramatically improved. Except for the 120 mg/L salicylic acid addition group, the chlorophyll fluorescence parameters (Fv/Fm and YII), glutathione peroxidase (GSH-Px) and glutathione-S-transferase (GST) activities of all the other concentration groups were significantly higher than those of the Cd2+ stress group alone, p < 0.05.; the algal cell morphology in low concentration groups (30 mg/L and 60 mg/L) was also less damaged than those in the Cd2+ stress group alone. These indicate that the low concentrations of salicylic acid can counteract or protect the algal cells from Cd2+ attack, the mechanisms, on the one hand, might be related to the chelation of heavy metals by salicylic acid, resulting in the decrease of the toxicity of Cd2+; on the other hand, low concentrations of salicylic acid can stimulate the growth of these two algae, improve their photosynthetic efficiency and antioxidant capacity, as well as maintain the relative integrity of algal morphological structure.
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