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Tazart Z, Manganelli M, Scardala S, Buratti FM, Nigro Di Gregorio F, Douma M, Mouhri K, Testai E, Loudiki M. Remediation Strategies to Control Toxic Cyanobacterial Blooms: Effects of Macrophyte Aqueous Extracts on Microcystis aeruginosa (Growth, Toxin Production and Oxidative Stress Response) and on Bacterial Ectoenzymatic Activities. Microorganisms 2021; 9:microorganisms9081782. [PMID: 34442861 PMCID: PMC8400474 DOI: 10.3390/microorganisms9081782] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/11/2021] [Accepted: 08/12/2021] [Indexed: 11/16/2022] Open
Abstract
Increasing toxic cyanobacterial blooms in freshwater demand environmentally friendly solutions to control their growth and toxicity, especially in arid countries, where most drinking water is produced from surface reservoirs. We tested the effects of macrophyte allelochemicals on Microcystis aeruginosa and on the fundamental role of bacteria in nutrient recycling. The effects of Ranunculus aquatilis aqueous extract, the most bioactive of four Moroccan macrophyte extracts, were tested in batch systems on M. aeruginosa growth, toxin production and oxidative stress response and on the ectoenzymatic activity associated with the bacterial community. M. aeruginosa density was reduced by 82.18%, and a significant increase in oxidative stress markers was evidenced in cyanobacterial cells. Microcystin concentration significantly decreased, and they were detected only intracellularly, an important aspect in managing toxic blooms. R. aquatilis extract had no negative effects on associated bacteria. These results confirm a promising use of macrophyte extracts, but they cannot be generalized. The use of the extract on other toxic strains, such as Planktothrix rubescens, Raphidiopsis raciborskii and Chrysosporum ovalisporum, caused a reduction in growth rate but not in cyanotoxin content, increasing toxicity. The need to assess species-specific cyanobacteria responses to verify the efficacy and safety of the extracts for human health and the environment is highlighted.
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Affiliation(s)
- Zakaria Tazart
- Istituto Superiore di Sanità, Environment & Health Department, Viale Regina Elena, 299, 00161 Rome, Italy; (Z.T.); (S.S.); (F.M.B.); (F.N.D.G.); (E.T.)
- Water, Biodiversity and Climate Change Laboratory, Phycology, Biotechnology and Environmental Toxicology Research Unit, Faculty of Sciences Semlalia, Cadi Ayyad University, Av. Prince My Abdellah P.O. Box 2390, Marrakech 40000, Morocco; (K.M.); (M.L.)
| | - Maura Manganelli
- Istituto Superiore di Sanità, Environment & Health Department, Viale Regina Elena, 299, 00161 Rome, Italy; (Z.T.); (S.S.); (F.M.B.); (F.N.D.G.); (E.T.)
- Correspondence:
| | - Simona Scardala
- Istituto Superiore di Sanità, Environment & Health Department, Viale Regina Elena, 299, 00161 Rome, Italy; (Z.T.); (S.S.); (F.M.B.); (F.N.D.G.); (E.T.)
| | - Franca Maria Buratti
- Istituto Superiore di Sanità, Environment & Health Department, Viale Regina Elena, 299, 00161 Rome, Italy; (Z.T.); (S.S.); (F.M.B.); (F.N.D.G.); (E.T.)
| | - Federica Nigro Di Gregorio
- Istituto Superiore di Sanità, Environment & Health Department, Viale Regina Elena, 299, 00161 Rome, Italy; (Z.T.); (S.S.); (F.M.B.); (F.N.D.G.); (E.T.)
| | - Mountasser Douma
- Environmental Microbiology and Toxicology Research Unit, Polydisciplinary Faculty of Khouribga (FPK), Sultan Moulay Slimane University, Beni Mellal 23000, Morocco;
| | - Khadija Mouhri
- Water, Biodiversity and Climate Change Laboratory, Phycology, Biotechnology and Environmental Toxicology Research Unit, Faculty of Sciences Semlalia, Cadi Ayyad University, Av. Prince My Abdellah P.O. Box 2390, Marrakech 40000, Morocco; (K.M.); (M.L.)
| | - Emanuela Testai
- Istituto Superiore di Sanità, Environment & Health Department, Viale Regina Elena, 299, 00161 Rome, Italy; (Z.T.); (S.S.); (F.M.B.); (F.N.D.G.); (E.T.)
| | - Mohammed Loudiki
- Water, Biodiversity and Climate Change Laboratory, Phycology, Biotechnology and Environmental Toxicology Research Unit, Faculty of Sciences Semlalia, Cadi Ayyad University, Av. Prince My Abdellah P.O. Box 2390, Marrakech 40000, Morocco; (K.M.); (M.L.)
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