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Mohan R, Pillai SS, Purushothaman A, Thomas LC, Padmakumar KB. Phylogenic diversity of bacteria associated with potentially toxic cyanobacteria Microcystis aeruginosa: a synthesis on its bloom dynamics. Folia Microbiol (Praha) 2024; 69:677-691. [PMID: 37991690 DOI: 10.1007/s12223-023-01108-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 11/10/2023] [Indexed: 11/23/2023]
Abstract
The occurrence of toxic bloom-forming cyanobacteria, Microcystis aeruginosa, has been frequently reported worldwide. These colony forming toxic cyanobacteria harbour a wide range of heterotrophic bacterial communities. The present study has attempted to understand the bloom dynamics of M. aeruginosa along with isolating their colony-associated culturable heterotrophic bacteria from two freshwater ponds in south India with a persisting cyanobacterial bloom. The monthly monitoring of these study areas revealed the conducive role of warm, stagnant waters with high nutrients in forming M. aeruginosa bloom. The peak values of temperature, nitrate, and phosphate at station 1 reached up to 30.5 °C, 4.48 mg/L, 1.64 mg/L, and at station 2, 31 °C, 3.45 mg/L, and 0.62 mg/L, respectively. Twenty-eight bacterial isolates belonging to Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Actinobacteria, and Firmicutes were obtained during the study. Among these 28 isolates, Firmicutes was dominant with the M. aeruginosa bloom from both the study areas.
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Affiliation(s)
- Renju Mohan
- Department of Marine Biology, Microbiology & Biochemistry, School of Marine Sciences, Cochin University of Science and Technology, Kochi-16, Kerala, India
| | - Sreya S Pillai
- Department of Marine Biology, Microbiology & Biochemistry, School of Marine Sciences, Cochin University of Science and Technology, Kochi-16, Kerala, India
| | - Aishwarya Purushothaman
- Department of Marine Biology, Microbiology & Biochemistry, School of Marine Sciences, Cochin University of Science and Technology, Kochi-16, Kerala, India
| | - Lathika Cicily Thomas
- Department of Marine Biology, Microbiology & Biochemistry, School of Marine Sciences, Cochin University of Science and Technology, Kochi-16, Kerala, India
| | - K B Padmakumar
- Department of Marine Biology, Microbiology & Biochemistry, School of Marine Sciences, Cochin University of Science and Technology, Kochi-16, Kerala, India.
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Mohammed V, Arockiaraj J. Unveiling the trifecta of cyanobacterial quorum sensing: LuxI, LuxR and LuxS as the intricate machinery for harmful algal bloom formation in freshwater ecosystems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 924:171644. [PMID: 38471587 DOI: 10.1016/j.scitotenv.2024.171644] [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: 06/28/2023] [Revised: 02/22/2024] [Accepted: 03/09/2024] [Indexed: 03/14/2024]
Abstract
Harmful algal blooms (HABs) are causing significant disruptions in freshwater ecosystems, primarily due to the proliferation of cyanobacteria. These blooms have a widespread impact on various lakes globally, leading to profound environmental and health consequences. Cyanobacteria, with their ability to produce diverse toxins, pose a particular concern as they negatively affect the well-being of humans and animals, exacerbating the situation. Notably, cyanobacteria utilize quorum sensing (QS) as a complex communication mechanism that facilitates coordinated growth and toxin production. QS plays a critical role in regulating the dynamics of HABs. However, recent advances in control and mitigation strategies have shown promising results in effectively managing and reducing the occurrence of HABs. This comprehensive review explores the intricate aspects of cyanobacteria development in freshwater ecosystems, explicitly focusing on deciphering the signaling molecules associated with QS and their corresponding genes. Furthermore, a concise overview of diverse measures implemented to efficiently control and mitigate the spread of these bacteria will be provided, shedding light on the ongoing global efforts to address this urgent environmental issue. By deepening our understanding of the mechanisms driving cyanobacteria growth and developing targeted control strategies, we hope to safeguard freshwater ecosystems and protect the health of humans and animals from the detrimental impacts of HABs.
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Affiliation(s)
- Vajagathali Mohammed
- Department of Forensic Science, Yenepoya Institute of Arts, Science, Commerce, and Management, Yenepoya (Deemed to be University), Mangaluru 575013, Karnataka, India
| | - Jesu Arockiaraj
- Toxicology and Pharmacology Laboratory, Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulathur 603203, Chengalpattu District, Tamil Nadu, India.
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Zheng D, Zou L, Zou J, Li Q, Lu S. Refining taxonomic identification of microalgae through molecular and genetic evolution: a case study of Prorocentrum lima and Prorocentrum arenarium. Microbiol Spectr 2024; 12:e0236723. [PMID: 38572997 PMCID: PMC11064606 DOI: 10.1128/spectrum.02367-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 02/08/2024] [Indexed: 04/05/2024] Open
Abstract
Species delimitation based on lineage definition has become increasingly popular. However, these methods have been limited, especially for species that lack genomic data and are morphologically similar. The trickiest part for the species identification is that the interspecific and intraspecific boundaries are vague. Taking Prorocentrum (Dinophyta) as an example, analysis of cell morphology, growth, and toxin synthesis in both species of P. lima and P. arenarium does not provide a reliable basis for species delineation. However, through phylogenetic and genetic distance analyses of their ITS and LSU sequences, establishment of evolutionary tree based on orthologous gene sequences, and combining the results of automatic barcode gap discovery and Poisson tree processes models, it was sustained that P. arenarium does not belong to the P. lima complex and should be considered as an independent species. Interspecies genetic evolution analysis revealed that P. lima and P. arenarium may contribute to evolutionary direction that favors combating reverse environmental factors. In P. lima, viral invasion may be one of the reasons for its large genome size. In the study, P. lima complex has been selected as an example to enhance the taxonomic identification of microalgae through molecular and genetic evolution, offering valuable insights into refining taxonomic identification and promoting microbial biodiversity research in other species.IMPORTANCEMicroalgae, especially the species known as Prorocentrum, have received significant attention due to their ability to trigger harmful algal blooms and produce toxins. However, the boundaries between species and within species are ambiguous. Clear and comprehensive species delineation indicates that Prorocentrum arenarium should be considered as an independent species, separate from the Prorocentrum lima complex. Improving the classification and identification of microalgae through molecular and genetic evolution will provide reference points for other cryptic species. Prorocentrum occupy multiple ecological niches in marine environments, and studying their evolutionary direction contributes to understanding their ecological adaptations and community succession.
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Affiliation(s)
- Danlin Zheng
- College of Life Science and Technology, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Jinan University, Guangzhou, China
| | - Ligong Zou
- College of Life Science and Technology, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Jinan University, Guangzhou, China
| | - Jian Zou
- College of Life Science and Technology, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Jinan University, Guangzhou, China
| | - Qun Li
- College of Life Science and Technology, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Jinan University, Guangzhou, China
| | - Songhui Lu
- College of Life Science and Technology, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Jinan University, Guangzhou, China
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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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Piccini C, Martínez de la Escalera G, Segura AM, Croci C, Kruk C. The Microcystis-microbiome interactions: origins of the colonial lifestyle. FEMS Microbiol Ecol 2024; 100:fiae035. [PMID: 38499447 PMCID: PMC10996927 DOI: 10.1093/femsec/fiae035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/21/2024] [Accepted: 03/16/2024] [Indexed: 03/20/2024] Open
Abstract
Species of the Microcystis genus are the most common bloom-forming toxic cyanobacteria worldwide. They belong to a clade of unicellular cyanobacteria whose ability to reach high biomasses during blooms is linked to the formation of colonies. Colonial lifestyle provides several advantages under stressing conditions of light intensity, ultraviolet light, toxic substances and grazing. The progression from a single-celled organism to multicellularity in Microcystis has usually been interpreted as individual phenotypic responses of the cyanobacterial cells to the environment. Here, we synthesize current knowledge about Microcystis colonial lifestyle and its role in the organism ecology. We then briefly review the available information on Microcystis microbiome and propose that changes leading from single cells to colonies are the consequence of specific and tightly regulated signals between the cyanobacterium and its microbiome through a biofilm-like mechanism. The resulting colony is a multi-specific community of interdependent microorganisms.
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Affiliation(s)
- Claudia Piccini
- Departamento de Microbiología, Centro de Investigación en Ciencias Ambientales, Instituto de Investigaciones Biológicas Clemente Estable. Av. Italia 3318, Montevideo 11600, Uruguay
| | - Gabriela Martínez de la Escalera
- Departamento de Microbiología, Centro de Investigación en Ciencias Ambientales, Instituto de Investigaciones Biológicas Clemente Estable. Av. Italia 3318, Montevideo 11600, Uruguay
| | - Angel M Segura
- Modelización Estadística de Datos e Inteligencia Artificial, Centro Universitario Regional del Este, Universidad de la República. Ruta nacional Nº9 intersección con ruta Nº15, Uruguay
| | - Carolina Croci
- Departamento de Microbiología, Centro de Investigación en Ciencias Ambientales, Instituto de Investigaciones Biológicas Clemente Estable. Av. Italia 3318, Montevideo 11600, Uruguay
| | - Carla Kruk
- Modelización Estadística de Datos e Inteligencia Artificial, Centro Universitario Regional del Este, Universidad de la República. Ruta nacional Nº9 intersección con ruta Nº15, Uruguay
- Sección Limnología, Instituto de Ecología y Ciencias Ambientales, Facultad de Ciencias, Universidad de la República. Iguá 4225, Montevideo 11400, Uruguay
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Zhu X, Zhan Y, Jia X, Li M, Yin T, Wang J. Combined effects of spinetoram and Microcystis aeruginosa on Daphnia pulex offspring: Maternal effects and multigenerational implications. CHEMOSPHERE 2024; 352:141376. [PMID: 38316281 DOI: 10.1016/j.chemosphere.2024.141376] [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: 01/02/2024] [Revised: 01/25/2024] [Accepted: 02/02/2024] [Indexed: 02/07/2024]
Abstract
The increasing occurrence of harmful algal blooms (HABs) in freshwater ecosystems detrimentally affect global water environments. Zooplankton's role in controlling HABs is hindered by contaminant exposure, necessitating research into combined stressors' ecological impacts. The response of Daphnia, a freshwater keystone species, to environmental stressors can be influenced by its maternal effects. Here, we investigated the combined effects of the world-widely used insecticide spinetoram and non-toxic HABs species Microcystis aeruginosa on the life-history traits of D. pulex offspring produced from different maternal food conditions. Four maternal groups were established, with each group receiving a specific blend of C. vulgaris (Ch) and M. aeruginosa (Ma) in varying proportions: A (100% Ch), B (90% Ch + 10% Ma), C (80% Ch + 20% Ma), and D (70% Ch + 30% Ma). The offspring from the third brood were gathered, and a 21-day experiment was carried out, involving various feeding groups (AA, AD, BA, BB, CA, CC, DA, and DD). Results demonstrated that grazing on M. aeruginosa by D. pulex induced maternal effects on their offspring, with the continuous exposure group showing an enhanced tolerance to M. aeruginosa. This study also unveiled that spinetoram could interfere with the molting of D. pulex, leading to developmental retardation. The Recovery Group exhibited an intriguing phenomenon: under the influence of both concentrations of the pesticide spinetoram (0.18, 0.35 μg L-1), D. pulex produced more offspring. This might be due to a combined strategy of allocating more energy towards reproduction in response to low-quality food and a potential hormetic effect from low concentrations of spinetoram. Assessing the interplay of combined stressors across multiple generations, encompassing harmful algal blooms (HABs) and environmental pollutants, is essential for predicting population responses to evolving environmental conditions. This understanding is vital for the protection and management of aquatic environments and ecosystems.
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Affiliation(s)
- Xuexia Zhu
- College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, China; College of Oceanography, Hohai University, Nanjing, 210049, China
| | - Yihe Zhan
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Xuanhe Jia
- College of Oceanography, Hohai University, Nanjing, 210049, China; State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academic of Sciences, Nanjing, 210008, China
| | - Meng Li
- College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, China
| | - Tianchi Yin
- College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, China
| | - Jun Wang
- College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, China.
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Kim W, Park Y, Jung J, Jeon CO, Toyofuku M, Lee J, Park W. Biological and Chemical Approaches for Controlling Harmful Microcystis Blooms. J Microbiol 2024; 62:249-260. [PMID: 38587591 DOI: 10.1007/s12275-024-00115-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 01/16/2024] [Accepted: 01/17/2024] [Indexed: 04/09/2024]
Abstract
The proliferation of harmful cyanobacterial blooms dominated by Microcystis aeruginosa has become an increasingly serious problem in freshwater ecosystems due to climate change and eutrophication. Microcystis-blooms in freshwater generate compounds with unpleasant odors, reduce the levels of dissolved O2, and excrete microcystins into aquatic ecosystems, potentially harming various organisms, including humans. Various chemical and biological approaches have thus been developed to mitigate the impact of the blooms, though issues such as secondary pollution and high economic costs have not been adequately addressed. Red clays and H2O2 are conventional treatment methods that have been employed worldwide for the mitigation of the blooms, while novel approaches, such as the use of plant or microbial metabolites and antagonistic bacteria, have also recently been proposed. Many of these methods rely on the generation of reactive oxygen species, the inhibition of photosynthesis, and/or the disruption of cellular membranes as their mechanisms of action, which may also negatively impact other freshwater microbiota. Nevertheless, the underlying molecular mechanisms of anticyanobacterial chemicals and antagonistic bacteria remain unclear. This review thus discusses both conventional and innovative approaches for the management of M. aeruginosa in freshwater bodies.
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Affiliation(s)
- Wonjae Kim
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Yerim Park
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Jaejoon Jung
- Department of Life Science, Chung-Ang University, Seoul, 02841, Republic of Korea
| | - Che Ok Jeon
- Department of Life Science, Chung-Ang University, Seoul, 02841, Republic of Korea
| | - Masanori Toyofuku
- Department of Life and Environmental Sciences, University of Tsukuba, Tsukuba, 305-0006, Japan
| | - Jiyoung Lee
- Division of Environmental Health Sciences, College of Public Health, The Ohio State University, Columbus, OH, 43210, USA
- Department of Food Science and Technology, The Ohio State University, Columbus, OH, 43210, USA
| | - Woojun Park
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea.
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Kiledal EA, Reitz LA, Kuiper EQ, Evans J, Siddiqui R, Denef VJ, Dick GJ. Comparative genomic analysis of Microcystis strain diversity using conserved marker genes. HARMFUL ALGAE 2024; 132:102580. [PMID: 38331539 DOI: 10.1016/j.hal.2024.102580] [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: 04/25/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 02/10/2024]
Abstract
Microcystis-dominated cyanobacterial harmful algal blooms (cyanoHABs) have a global impact on freshwater environments, affecting both wildlife and human health. Microcystis diversity and function in field samples and laboratory cultures can be determined by sequencing whole genomes of cultured isolates or natural populations, but these methods remain computationally and financially expensive. Amplicon sequencing of marker genes is a lower cost and higher throughput alternative to characterize strain composition and diversity in mixed samples. However, the selection of appropriate marker gene region(s) and primers requires prior understanding of the relationship between single gene genotype, whole genome content, and phenotype. To identify phylogenetic markers of Microcystis strain diversity, we compared phylogenetic trees built from each of 2,351 individual core genes to an established phylogeny and assessed the ability of these core genes to predict whole genome content and bioactive compound genotypes. We identified single-copy core genes better able to resolve Microcystis phylogenies than previously identified marker genes. We developed primers suitable for current Illumina-based amplicon sequencing with near-complete coverage of available Microcystis genomes and demonstrate that they outperform existing options for assessing Microcystis strain composition. Results showed that genetic markers can be used to infer Microcystis gene content and phenotypes such as potential production of bioactive compounds , although marker performance varies by bioactive compound gene and sequence similarity. Finally, we demonstrate that these markers can be used to characterize the Microcystis strain composition of laboratory or field samples like those collected for surveillance and modeling of Microcystis-dominated cyanobacterial harmful algal blooms.
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Affiliation(s)
- E Anders Kiledal
- Department of Earth and Environmental Sciences, University of Michigan, 2534 North University Building, 1100 North University Avenue Ave, Rm. 2004, Ann Arbor, MI 48109-1005, USA.
| | - Laura A Reitz
- Department of Earth and Environmental Sciences, University of Michigan, 2534 North University Building, 1100 North University Avenue Ave, Rm. 2004, Ann Arbor, MI 48109-1005, USA
| | - Esmée Q Kuiper
- Department of Earth and Environmental Sciences, University of Michigan, 2534 North University Building, 1100 North University Avenue Ave, Rm. 2004, Ann Arbor, MI 48109-1005, USA
| | - Jacob Evans
- Department of Ecology and Evolutionary Biology, University of Michigan, 2220 Biological Sciences Building, 1105 North University Avenue, Ann Arbor, MI 48109-1005, USA
| | - Ruqaiya Siddiqui
- Microbiome Core, University of Michigan, 1500 MSRB 1, 1150W Medical Center Drive, Ann Arbor, MI 48109-5666, USA
| | - Vincent J Denef
- Department of Ecology and Evolutionary Biology, University of Michigan, 2220 Biological Sciences Building, 1105 North University Avenue, Ann Arbor, MI 48109-1005, USA
| | - Gregory J Dick
- Department of Earth and Environmental Sciences, University of Michigan, 2534 North University Building, 1100 North University Avenue Ave, Rm. 2004, Ann Arbor, MI 48109-1005, USA; Cooperative Institute for Great Lakes Research, University of Michigan, 4040 Dana Building, 440 Church Street, Ann Arbor, MI 48109-1041, USA
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Romanis CS, Timms VJ, Nebauer DJ, Crosbie ND, Neilan BA. Microbiome analysis reveals Microcystis blooms endogenously seeded from benthos within wastewater maturation ponds. Appl Environ Microbiol 2024; 90:e0158523. [PMID: 38117057 PMCID: PMC10807444 DOI: 10.1128/aem.01585-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 10/27/2023] [Indexed: 12/21/2023] Open
Abstract
Toxigenic Microcystis blooms periodically disrupt the stabilization ponds of wastewater treatment plants (WWTPs). Dense proliferations of Microcystis cells within the surface waters (SWs) impede the water treatment process by reducing the treatment efficacy of the latent WWTP microbiome. Further, water quality is reduced when conventional treatment leads to Microcystis cell lysis and the release of intracellular microcystins into the water column. Recurrent seasonal Microcystis blooms cause significant financial burdens for the water industry and predicting their source is vital for bloom management strategies. We investigated the source of recurrent toxigenic Microcystis blooms at Australia's largest lagoon-based municipal WWTP in both sediment core (SC) and SW samples between 2018 and 2020. Bacterial community composition of the SC and SW samples according to 16S rRNA gene amplicon sequencing showed that Microcystis sp. was dominant within SW samples throughout the period and reached peak relative abundances (32%) during the summer. The same Microcystis Amplicon sequence variants were present within the SC and SW samples indicating a potential migratory population that transitions between the sediment water and SWs during bloom formation events. To investigate the potential of the sediment to act as a repository of viable Microcystis cells for recurrent bloom formation, a novel in-vitro bloom model was established featuring sediments and sterilized SW collected from the WWTP. Microcystin-producing Microcystis blooms were established through passive resuspension after 12 weeks of incubation. These results demonstrate the capacity of Microcystis to transition between the sediments and SWs in WWTPs, acting as a perennial inoculum for recurrent blooms.IMPORTANCECyanobacterial blooms are prevalent to wastewater treatment facilities owing to the stable, eutrophic conditions. Cyanobacterial proliferations can disrupt operational procedures through the blocking of filtration apparatus or altering the wastewater treatment plant (WWTP) microbiome, reducing treatment efficiency. Conventional wastewater treatment often results in the lysis of cyanobacterial cells and the release of intracellular toxins which pose a health risk to end users. This research identifies a potential seeding source of recurrent toxigenic cyanobacterial blooms within wastewater treatment facilities. Our results demonstrate the capacity of Microcystis to transition between the sediments and surface waters (SWs) of wastewater treatment ponds enabling water utilities to develop adequate monitoring and management strategies. Further, we developed a novel model to demonstrate benthic recruitment of toxigenic Microcystis under laboratory conditions facilitating future research into the genetic mechanisms behind bloom development.
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Affiliation(s)
- C. S. Romanis
- University of Newcastle, School of Environmental and Life Sciences, Callaghan, Australia
| | - V. J. Timms
- University of Newcastle, School of Environmental and Life Sciences, Callaghan, Australia
- ARC Centre of Excellence for Synthetic Biology, Callaghan, Australia
| | - D. J. Nebauer
- University of Newcastle, School of Environmental and Life Sciences, Callaghan, Australia
| | | | - B. A. Neilan
- University of Newcastle, School of Environmental and Life Sciences, Callaghan, Australia
- ARC Centre of Excellence for Synthetic Biology, Callaghan, Australia
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Li W, Baliu-Rodriguez D, Premathilaka SH, Thenuwara SI, Kimbrel JA, Samo TJ, Ramon C, Kiledal EA, Rivera SR, Kharbush J, Isailovic D, Weber PK, Dick GJ, Mayali X. Microbiome processing of organic nitrogen input supports growth and cyanotoxin production of Microcystis aeruginosa cultures. THE ISME JOURNAL 2024; 18:wrae082. [PMID: 38718148 PMCID: PMC11126159 DOI: 10.1093/ismejo/wrae082] [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: 01/11/2024] [Revised: 04/01/2024] [Accepted: 05/02/2024] [Indexed: 05/26/2024]
Abstract
Nutrient-induced blooms of the globally abundant freshwater toxic cyanobacterium Microcystis cause worldwide public and ecosystem health concerns. The response of Microcystis growth and toxin production to new and recycled nitrogen (N) inputs and the impact of heterotrophic bacteria in the Microcystis phycosphere on these processes are not well understood. Here, using microbiome transplant experiments, cyanotoxin analysis, and nanometer-scale stable isotope probing to measure N incorporation and exchange at single cell resolution, we monitored the growth, cyanotoxin production, and microbiome community structure of several Microcystis strains grown on amino acids or proteins as the sole N source. We demonstrate that the type of organic N available shaped the microbial community associated with Microcystis, and external organic N input led to decreased bacterial colonization of Microcystis colonies. Our data also suggest that certain Microcystis strains could directly uptake amino acids, but with lower rates than heterotrophic bacteria. Toxin analysis showed that biomass-specific microcystin production was not impacted by N source (i.e. nitrate, amino acids, or protein) but rather by total N availability. Single-cell isotope incorporation revealed that some bacterial communities competed with Microcystis for organic N, but other communities promoted increased N uptake by Microcystis, likely through ammonification or organic N modification. Our laboratory culture data suggest that organic N input could support Microcystis blooms and toxin production in nature, and Microcystis-associated microbial communities likely play critical roles in this process by influencing cyanobacterial succession through either decreasing (via competition) or increasing (via biotransformation) N availability, especially under inorganic N scarcity.
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Affiliation(s)
- Wei Li
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States
| | - David Baliu-Rodriguez
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, United States
| | - Sanduni H Premathilaka
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, United States
| | - Sharmila I Thenuwara
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, United States
| | - Jeffrey A Kimbrel
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States
| | - Ty J Samo
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States
| | - Christina Ramon
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States
| | - Erik Anders Kiledal
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48104, United States
| | - Sara R Rivera
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48104, United States
| | - Jenan Kharbush
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48104, United States
| | - Dragan Isailovic
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, United States
| | - Peter K Weber
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States
| | - Gregory J Dick
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48104, United States
- Cooperative Institute for Great Lakes Research, University of Michigan, Ann Arbor, MI 48104, United States
| | - Xavier Mayali
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States
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11
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Jia Y, Huang Y, Ma J, Zhang S, Liu J, Li T, Song L. Toxicity of the disinfectant benzalkonium chloride (C 14) towards cyanobacterium Microcystis results from its impact on the photosynthetic apparatus and cell metabolism. J Environ Sci (China) 2024; 135:198-209. [PMID: 37778795 DOI: 10.1016/j.jes.2022.11.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/07/2022] [Accepted: 11/07/2022] [Indexed: 10/03/2023]
Abstract
Quaternary ammonium compounds (QACs) are commonly used in a variety of consumer and commercial products, typically as a component of disinfectants. During the COVID-19 pandemic, QACs became one of the primary agents utilized to inactivate the SARS-CoV-2 virus on surfaces. However, the ecotoxicological effects of QACs upon aquatic organisms have not been fully assessed. In this study, we examined the effects of a widely used QAC (benzalkonium chloride-C14, BAC-14) on two toxigenic Microcystis strains and one non-toxigenic freshwater Microcystis strain and carried out an analysis focused on primary, adaptive and compensatory stress responses at apical (growth and photosynthesis) and metabolic levels. This analysis revealed that the two toxic Microcystis strains were more tolerant than the non-toxic strain, with 96 hr-EC50 values of 0.70, 0.76, and 0.38 mg/L BAC-14 for toxigenic M. aeruginosa FACHB-905, toxigenic M. aeruginosa FACHB-469, and non-toxigenic M. wesenbergii FACHB-908, respectively. The photosynthetic activities of the Microcystis, assessed via Fv/Fm values, were significantly suppressed under 0.4 mg/L BAC-14. Furthermore, this analysis revealed that BAC-14 altered 14, 12, and 8 metabolic pathways in M. aeruginosa FACHB-905, M. aeruginosa FACHB-469, and M. wesenbergii FACHB-908, respectively. It is noteworthy that BAC-14 enhanced the level of extracellular microcystin production in the toxigenic Microcystis strains, although cell growth was not significantly affected. Collectively, these data show that BAC-14 disrupted the physiological and metabolic status of Microcystis cells and stimulated the production and release of microcystin, which could result in damage to aquatic systems.
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Affiliation(s)
- Yunlu Jia
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
| | - Yi Huang
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, China
| | - Jin Ma
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, China
| | - Shangwei Zhang
- Advanced Interdisciplinary Institute of Environment and Ecology, Beijing Normal University, Zhuhai 519087, China
| | - Jin Liu
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Tianli Li
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Lirong Song
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
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12
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Wu H, Zhang W, Huang X, Gu P, Li Q, Luo X, Zheng Z. Phosphorus conditions change the cellular responses of Microcystis aeruginosa to perfluorooctanoic acid. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166707. [PMID: 37660808 DOI: 10.1016/j.scitotenv.2023.166707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/28/2023] [Accepted: 08/28/2023] [Indexed: 09/05/2023]
Abstract
Perfluorooctanoic acid (PFOA), a widespread and emerging organic contaminant of aquatic environments, has high bioaccumulation potential and high toxicity. Consequently, major concerns have been raised worldwide regarding the management of this pollutant in aquatic ecosystems. To thoroughly understand PFOA's toxic effects on aquatic organisms, systematic investigations were conducted on the cellular responses of Microcystis aeruginosa to the environmental concentrations of PFOA under various concentrations as well as phosphorus (P) conditions (concentrations and forms). The results showed that P conditions remarkably affected cyanobacterial growth as well as photosynthetic pigment content, triggered oxidative stress to disrupt the function and structure of the cell membrane, and caused changes in the extracellular and intracellular contents of microcystin-LR (MC-LR). Furthermore, PFOA (100 μg/L) was absorbed by cyanobacterial cells through the stimulation of the secretion of extracellular polymeric substances (EPS) by M. aeruginosa. After entering the cyanobacterial cells, PFOA inhibited photosynthesis, reduced P absorption, induced oxidative damage, lead to a loss of cell integrity evident in scanning electron microscope images, and increased mcyA gene expression to promote MC-LR production. Moreover, the limited P concentration and forms conditions led to increased PFOA absorption by cyanobacterial cells, which further upregulated mcyA gene expression and increased the risk of MC-LR diffusion into the aquatic environment. Our present study provided a theoretical basis and new ideas for understanding and addressing safety issues related to the presence of PFOA in aquatic environments with varying nutritional statuses.
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Affiliation(s)
- Hanqi Wu
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, PR China
| | - Weizheng Zhang
- College of Ecology and Environment, Chengdu University of Technology, Chengdu 610059, PR China
| | - Xuhui Huang
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, PR China
| | - Peng Gu
- School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, PR China
| | - Qi Li
- College of Ecology and Environment, Chengdu University of Technology, Chengdu 610059, PR China
| | - Xingzhang Luo
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, PR China
| | - Zheng Zheng
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, PR China.
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13
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Baker D, Godwin CM, Khanam M, Burtner AM, Dick GJ, Denef VJ. Variation in resource competition traits among Microcystis strains is affected by their microbiomes. MLIFE 2023; 2:401-415. [PMID: 38818269 PMCID: PMC10989160 DOI: 10.1002/mlf2.12094] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 10/11/2023] [Accepted: 10/13/2023] [Indexed: 06/01/2024]
Abstract
Freshwater harmful algal blooms are often dominated by Microcystis, a phylogenetically cohesive group of cyanobacteria marked by extensive genetic and physiological diversity. We have previously shown that this genetic diversity and the presence of a microbiome of heterotrophic bacteria influences competitive interactions with eukaryotic phytoplankton. In this study, we sought to explain these observations by characterizing Monod equation parameters for resource usage (maximum growth rate μ max, half-saturation value for growth K s, and quota) as a function of N and P levels for four strains (NIES-843, PCC 9701, PCC 7806 [WT], and PCC 7806 ΔmcyB) in presence and absence of a microbiome derived from Microcystis isolated from Lake Erie. Results indicated limited differences in maximum growth rates but more pronounced differences in half-saturation values among Microcystis strains. The largest impact of the microbiome was reducing the minimal nitrogen concentration sustaining growth and reducing half saturation values, with variable results depending on the Microcystis strain. Microcystis strains also differed from each other in their N and P quotas and the extent to which microbiome presence affected them. Our data highlight the importance of the microbiome in altering Microcystis-intrinsic traits, strain competitive hierarchies, and thus bloom dynamics. As quota, μ max, and K s are commonly used in models for harmful algal blooms, our data suggest that model improvement may be possible by incorporating genotype dependencies of resource-use parameters.
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Affiliation(s)
- Dylan Baker
- Department of Ecology and Evolutionary BiologyUniversity of MichiganAnn ArborMichiganUSA
| | - Casey M. Godwin
- Cooperative Institute for Great Lakes Research, School for Environment and SustainabilityUniversity of MichiganAnn ArborMichiganUSA
| | - Muhtamim Khanam
- Department of Ecology and Evolutionary BiologyUniversity of MichiganAnn ArborMichiganUSA
| | - Ashley M. Burtner
- Cooperative Institute for Great Lakes Research, School for Environment and SustainabilityUniversity of MichiganAnn ArborMichiganUSA
| | - Gregory J. Dick
- Cooperative Institute for Great Lakes Research, School for Environment and SustainabilityUniversity of MichiganAnn ArborMichiganUSA
- Department of Earth and Environmental SciencesUniversity of MichiganAnn ArborMichiganUSA
| | - Vincent J. Denef
- Department of Ecology and Evolutionary BiologyUniversity of MichiganAnn ArborMichiganUSA
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14
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Stark GF, Martin RM, Smith LE, Wei B, Hellweger FL, Bullerjahn GS, McKay RML, Boyer GL, Wilhelm SW. Microcystin aids in cold temperature acclimation: Differences between a toxic Microcystis wildtype and non-toxic mutant. HARMFUL ALGAE 2023; 129:102531. [PMID: 37951605 PMCID: PMC10640677 DOI: 10.1016/j.hal.2023.102531] [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: 08/31/2023] [Revised: 10/20/2023] [Accepted: 10/20/2023] [Indexed: 11/14/2023]
Abstract
For Microcystis aeruginosa PCC 7806, temperature decreases from 26 °C to 19 °C double the microcystin quota per cell during growth in continuous culture. Here we tested whether this increase in microcystin provided M. aeruginosa PCC 7806 with a fitness advantage during colder-temperature growth by comparing cell concentration, cellular physiology, reactive oxygen species damage, and the transcriptomics-inferred metabolism to a non-toxigenic mutant strain M. aeruginosa PCC 7806 ΔmcyB. Photo-physiological data combined with transcriptomic data revealed metabolic changes in the mutant strain during growth at 19 °C, which included increased electron sinks and non-photochemical quenching. Increased gene expression was observed for a glutathione-dependent peroxiredoxin during cold treatment, suggesting compensatory mechanisms to defend against reactive oxygen species are employed in the absence of microcystin in the mutant. Our observations highlight the potential selective advantages of a longer-term defensive strategy in management of oxidative stress (i.e., making microcystin) vs the shorter-term proactive strategy of producing cellular components to actively dissipate or degrade oxidative stress agents.
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Affiliation(s)
- Gwendolyn F Stark
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
| | - Robbie M Martin
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
| | - Laura E Smith
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
| | - Bofan Wei
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, USA
| | - Ferdi L Hellweger
- Water Quality Engineering, Technical University of Berlin, Berlin, Germany
| | - George S Bullerjahn
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, USA
| | - R Michael L McKay
- Great Lakes Institute for Environmental Research, The University of Windsor, Windsor, ON, Canada
| | - Gregory L Boyer
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, USA
| | - Steven W Wilhelm
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA.
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15
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Collart L, Jiang D, Halsey KH. The volatilome reveals microcystin concentration, microbial composition, and oxidative stress in a critical Oregon freshwater lake. mSystems 2023; 8:e0037923. [PMID: 37589463 PMCID: PMC10654074 DOI: 10.1128/msystems.00379-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 07/03/2023] [Indexed: 08/18/2023] Open
Abstract
IMPORTANCE Harmful algal blooms are among the most significant threats to drinking water safety. Blooms dominated by cyanobacteria can produce potentially harmful toxins and, despite intensive research, toxin production remains unpredictable. We measured gaseous molecules in Upper Klamath Lake, Oregon, over 2 years and used them to predict the presence and concentration of the cyanotoxin, microcystin, and microbial community composition. Subsets of gaseous compounds were identified that are associated with microcystin production during oxidative stress, pointing to ecosystem-level interactions leading to microcystin contamination. Our approach shows potential for gaseous molecules to be harnessed in monitoring critical waterways.
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Affiliation(s)
- Lindsay Collart
- Department of Microbiology, Oregon State University, Corvallis, Oregon, USA
| | - Duo Jiang
- Department of Statistics, Oregon State University, Corvallis, Oregon, USA
| | - Kimberly H. Halsey
- Department of Microbiology, Oregon State University, Corvallis, Oregon, USA
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16
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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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17
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Thawabteh AM, Naseef HA, Karaman D, Bufo SA, Scrano L, Karaman R. Understanding the Risks of Diffusion of Cyanobacteria Toxins in Rivers, Lakes, and Potable Water. Toxins (Basel) 2023; 15:582. [PMID: 37756009 PMCID: PMC10535532 DOI: 10.3390/toxins15090582] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/10/2023] [Accepted: 09/18/2023] [Indexed: 09/28/2023] Open
Abstract
Blue-green algae, or cyanobacteria, may be prevalent in our rivers and tap water. These minuscule bacteria can grow swiftly and form blooms in warm, nutrient-rich water. Toxins produced by cyanobacteria can pollute rivers and streams and harm the liver and nervous system in humans. This review highlights the properties of 25 toxin types produced by 12 different cyanobacteria genera. The review also covered strategies for reducing and controlling cyanobacteria issues. These include using physical or chemical treatments, cutting back on fertilizer input, algal lawn scrubbers, and antagonistic microorganisms for biocontrol. Micro-, nano- and ultrafiltration techniques could be used for the removal of internal and extracellular cyanotoxins, in addition to powdered or granular activated carbon, ozonation, sedimentation, ultraviolet radiation, potassium permanganate, free chlorine, and pre-treatment oxidation techniques. The efficiency of treatment techniques for removing intracellular and extracellular cyanotoxins is also demonstrated. These approaches aim to lessen the risks of cyanobacterial blooms and associated toxins. Effective management of cyanobacteria in water systems depends on early detection and quick action. Cyanobacteria cells and their toxins can be detected using microscopy, molecular methods, chromatography, and spectroscopy. Understanding the causes of blooms and the many ways for their detection and elimination will help the management of this crucial environmental issue.
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Affiliation(s)
- Amin Mahmood Thawabteh
- Faculty of Pharmacy, Nursing and Health Professions, Birzeit University, Ramallah 00972, Palestine
- General Safety Section, General Services Department, Birzeit University, Bir Zeit 71939, Palestine
| | - Hani A Naseef
- Faculty of Pharmacy, Nursing and Health Professions, Birzeit University, Ramallah 00972, Palestine
| | - Donia Karaman
- Faculty of Pharmacy, Al-Quds University, Jerusalem 20002, Palestine
| | - Sabino A Bufo
- Department of Sciences, University of Basilicata, Via dell'Ateneo Lucano 10, 85100 Potenza, Italy
- Department of Geography, Environmental Management and Energy Studies, University of Johannesburg, Auckland Park Kingsway Campus, Johannesburg 2092, South Africa
| | - Laura Scrano
- Department of European and Mediterranean Cultures, University of Basilicata, Via Lanera 20, 75100 Matera, Italy
| | - Rafik Karaman
- Faculty of Pharmacy, Al-Quds University, Jerusalem 20002, Palestine
- Department of Sciences, University of Basilicata, Via dell'Ateneo Lucano 10, 85100 Potenza, Italy
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18
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Stark GF, Martin RM, Smith LE, Wei B, Hellweger FL, Bullerjahn GS, McKay RML, Boyer GL, Wilhelm SW. Cool temperature acclimation in toxigenic Microcystis aeruginosa PCC 7806 and its non-toxigenic mutant. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.28.555099. [PMID: 37693631 PMCID: PMC10491114 DOI: 10.1101/2023.08.28.555099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
For Microcystis aeruginosa PCC 7806, temperature decreases from 26° C to 19° C double the microcystin quota per cell during growth in continuous culture. Here we tested whether this increase in microcystin provided M. aeruginosa PCC 7806 with a fitness advantage during colder-temperature growth by comparing cell concentration, cellular physiology, and the transcriptomics-inferred metabolism to a non-toxigenic mutant strain M. aeruginosa PCC 7806 ΔmcyB. Photo-physiological data combined with transcriptomic data revealed metabolic changes in the mutant strain during growth at 19° C, which included increased electron sinks and non-photochemical quenching. Increased gene expression was observed for a glutathione-dependent peroxiredoxin during cold treatment, suggesting compensatory mechanisms to defend against reactive oxygen species are employed in the absence of microcystin in the mutant. Our observations highlight the potential selective advantages of a longer-term defensive strategy in management of oxidative stress (i.e., making microcystin) vs the shorter-term proactive strategy of producing cellular components to actively dissipate or degrade oxidative stress agents.
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Affiliation(s)
- Gwendolyn F Stark
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
| | - Robbie M Martin
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
| | - Laura E Smith
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
| | - Bofan Wei
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, USA
| | - Ferdi L Hellweger
- Water Quality Engineering, Technical University of Berlin, Berlin, Germany
| | - George S Bullerjahn
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, USA
| | - R Michael L McKay
- Great Lakes Institute for Environmental Research, The University of Windsor, Windsor, ON, Canada
| | - Gregory L Boyer
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, USA
| | - Steven W Wilhelm
- Department of Microbiology, The University of Tennessee, Knoxville, TN, USA
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19
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Zhang X, Xiao L, Liu J, Tian Q, Xie J. Trade-off in genome turnover events leading to adaptive evolution of Microcystis aeruginosa species complex. BMC Genomics 2023; 24:462. [PMID: 37592233 PMCID: PMC10433662 DOI: 10.1186/s12864-023-09555-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 08/04/2023] [Indexed: 08/19/2023] Open
Abstract
BACKGROUND Numerous studies in the past have expanded our understanding of the genetic differences of global distributed cyanobacteria that originated around billions of years ago, however, unraveling how gene gain and loss drive the genetic evolution of cyanobacterial species, and the trade-off of these evolutionary forces are still the central but poorly understood issues. RESULTS To delineate the contribution of gene flow in mediating the hereditary differentiation and shaping the microbial evolution, a global genome-wide study of bloom-forming cyanobacterium, Microcystis aeruginosa species complex, provided robust evidence for genetic diversity, reflected by enormous variation in gene repertoire among various strains. Mathematical extrapolation showed an 'open' microbial pan-genome of M. aeruginosa species, since novel genes were predicted to be introduced after new genomes were sequenced. Identification of numerous horizontal gene transfer's signatures in genome regions of interest suggested that genome expansion via transformation and phage-mediated transduction across bacterial lineage as an evolutionary route may contribute to the differentiation of Microcystis functions (e.g., carbohydrate metabolism, amino acid metabolism, and energy metabolism). Meanwhile, the selective loss of some dispensable genes at the cost of metabolic versatility is as a mean of adaptive evolution that has the potential to increase the biological fitness. CONCLUSIONS Now that the recruitment of novel genes was accompanied by a parallel loss of some other ones, a trade-off in gene content may drive the divergent differentiation of M. aeruginosa genomes. Our study provides a genetic framework for the evolution of M. aeruginosa species and illustrates their possible evolutionary patterns.
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Affiliation(s)
- 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.
| | - Lijun Xiao
- Guangdong Corps Hospital of Chinese People's Armed Police Forces, Guangzhou, China
| | - Jiahui Liu
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, Changsha, China
| | - Qibai Tian
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, Changsha, China
| | - Jiaqi Xie
- Hunan Food and Drug Vocational College, Changsha, China
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20
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Bashir F, Bashir A, Bouaïcha N, Chen L, Codd GA, Neilan B, Xu WL, Ziko L, Rajput VD, Minkina T, Arruda RS, Ganai BA. Cyanotoxins, biosynthetic gene clusters, and factors modulating cyanotoxin biosynthesis. World J Microbiol Biotechnol 2023; 39:241. [PMID: 37394567 DOI: 10.1007/s11274-023-03652-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 05/17/2023] [Indexed: 07/04/2023]
Abstract
Cyanobacterial harmful algal blooms (CHABs) are a global environmental concern that encompasses public health issues, water availability, and water quality owing to the production of various secondary metabolites (SMs), including cyanotoxins in freshwater, brackish water, and marine ecosystems. The frequency, extent, magnitude, and duration of CHABs are increasing globally. Cyanobacterial species traits and changing environmental conditions, including anthropogenic pressure, eutrophication, and global climate change, together allow cyanobacteria to thrive. The cyanotoxins include a diverse range of low molecular weight compounds with varying biochemical properties and modes of action. With the application of modern molecular biology techniques, many important aspects of cyanobacteria are being elucidated, including aspects of their diversity, gene-environment interactions, and genes that express cyanotoxins. The toxicological, environmental, and economic impacts of CHABs strongly advocate the need for continuing, extensive efforts to monitor cyanobacterial growth and to understand the mechanisms regulating species composition and cyanotoxin biosynthesis. In this review, we critically examined the genomic organization of some cyanobacterial species that lead to the production of cyanotoxins and their characteristic properties discovered to date.
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Affiliation(s)
- Fahim Bashir
- Department of Environmental Science, University of Kashmir, Srinagar, Jammu and Kashmir, 190006, India
| | - Arif Bashir
- Department of Clinical Biochemistry and Biotechnology, Government College for Women, Nawa-Kadal, Srinagar, Jammu & Kashmir, India
| | - Noureddine Bouaïcha
- Laboratory Ecology, Systematic, and Evolution, UMR 8079 Univ. Paris-Sud, CNRS, AgroParisTech, University Paris-Saclay, 91190, Gif-sur-Yvette, France.
| | - Liang Chen
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science (SEES), Yunnan University (YNU), 650500, Kunming, China.
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology (IHB), Chinese Academy of Sciences (CAS), Wuhan, 430072, China.
- State Key Laboratory of Eco-Hydraulics in Northwest Arid Region, Faculty of Water Resources and Hydroelectric Engineering, Xi'an University of Technology, Xi'an, 710048, China.
| | - Geoffrey A Codd
- Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, Scotland, UK
| | - Brett Neilan
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, Australia
| | - Wen-Li Xu
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology (IHB), Chinese Academy of Sciences (CAS), Wuhan, 430072, China
| | - Laila Ziko
- School of Life and Medical Sciences, University of Hertfordshire Hosted By Global Academic Foundation, Cairo, Egypt
- Biology Department, School of Sciences and Engineering, The American University in Cairo, New Cairo, 11835, Egypt
| | - Vishnu D Rajput
- Academy of Biology and Biotechnology, Southern Federal University, Rostov-On-Don, Russia
| | - Tatiana Minkina
- Academy of Biology and Biotechnology, Southern Federal University, Rostov-On-Don, Russia
| | - Renan Silva Arruda
- Laboratory of Ecology and Physiology of Phytoplankton, Department of Plant Biology, University of Rio de Janeiro State, Rio de Janeiro, Brazil
| | - Bashir Ahmad Ganai
- Center of Research for Development (CORD), University of Kashmir, Srinagar, Jammu and Kashmir, 190006, India.
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21
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Yancey CE, Yu F, Tripathi A, Sherman DH, Dick GJ. Expression of Microcystis Biosynthetic Gene Clusters in Natural Populations Suggests Temporally Dynamic Synthesis of Novel and Known Secondary Metabolites in Western Lake Erie. Appl Environ Microbiol 2023; 89:e0209222. [PMID: 37070981 PMCID: PMC10231183 DOI: 10.1128/aem.02092-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 03/02/2023] [Indexed: 04/19/2023] Open
Abstract
Microcystis spp. produce diverse secondary metabolites within freshwater cyanobacterial harmful algal blooms (cyanoHABs) around the world. In addition to the biosynthetic gene clusters (BGCs) encoding known compounds, Microcystis genomes harbor numerous BGCs of unknown function, indicating a poorly understood chemical repertoire. While recent studies show that Microcystis produces several metabolites in the lab and field, little work has focused on analyzing the abundance and expression of its broader suite of BGCs during cyanoHAB events. Here, we use metagenomic and metatranscriptomic approaches to track the relative abundance of Microcystis BGCs and their transcripts throughout the 2014 western Lake Erie cyanoHAB. The results indicate the presence of several transcriptionally active BGCs that are predicted to synthesize both known and novel secondary metabolites. The abundance and expression of these BGCs shifted throughout the bloom, with transcript abundance levels correlating with temperature, nitrate, and phosphorus concentrations and the abundance of co-occurring predatory and competitive eukaryotic microorganisms, suggesting the importance of both abiotic and biotic controls in regulating expression. This work highlights the need for understanding the chemical ecology and potential risks to human and environmental health posed by secondary metabolites that are produced but often unmonitored. It also indicates the prospects for identifying pharmaceutical-like molecules from cyanoHAB-derived BGCs. IMPORTANCE Microcystis spp. dominate cyanobacterial harmful algal blooms (cyanoHABs) worldwide and pose significant threats to water quality through the production of secondary metabolites, many of which are toxic. While the toxicity and biochemistry of microcystins and several other compounds have been studied, the broader suite of secondary metabolites produced by Microcystis remains poorly understood, leaving gaps in our understanding of their impacts on human and ecosystem health. We used community DNA and RNA sequences to track the diversity of genes encoding synthesis of secondary metabolites in natural Microcystis populations and assess patterns of transcription in western Lake Erie cyanoHABs. Our results reveal the presence of both known gene clusters that encode toxic secondary metabolites as well as novel ones that may encode cryptic compounds. This research highlights the need for targeted studies of the secondary metabolite diversity in western Lake Erie, a vital freshwater source to the United States and Canada.
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Affiliation(s)
- Colleen E. Yancey
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan, USA
| | - Fengan Yu
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Ashootosh Tripathi
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
- Natural Products Discovery Core, University of Michigan, Ann Arbor, Michigan, USA
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - David H. Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan, USA
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Gregory J. Dick
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan, USA
- Cooperative Institute for Great Lakes Research (CIGLR), University of Michigan, Ann Arbor, Michigan, USA
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22
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Shahmohamadloo RS, Bhavsar SP, Ortiz Almirall X, Marklevitz SAC, Rudman SM, Sibley PK. Cyanotoxins accumulate in Lake St. Clair fish yet their fillets are safe to eat. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 874:162381. [PMID: 36870491 DOI: 10.1016/j.scitotenv.2023.162381] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/16/2023] [Accepted: 02/17/2023] [Indexed: 06/18/2023]
Abstract
Consuming fish exposed to cyanobacterial harmful algal blooms (HABs) may be a major route of microcystin toxin exposure to humans. However, it remains unknown whether fish can accumulate and retain microcystins temporally in waterbodies with recurring seasonal HABs, particularly before and after a HAB event when fishing is active. We conducted a field study on Largemouth Bass, Northern Pike, Smallmouth Bass, Rock Bass, Walleye, White Bass, and Yellow Perch to assess the human health risks to microcystin toxicity via fish consumption. We collected 124 fish in 2016 and 2018 from Lake St. Clair, a large freshwater ecosystem in the North American Great Lakes that is actively fished pre- and post-HAB periods. Muscles were analyzed using the 2-methyl-3-methoxy-4-phenylbutyric acid (MMPB) Lemieux Oxidation method for total microcystins, which was used to perform a human health risk assessment for comparison against fish consumption advisory benchmarks available for Lake St. Clair. From this collection 35 fish livers were additionally extracted to confirm the presence of microcystins. Microcystins were detected in all livers at widely varying concentrations (1-1500 ng g-1 ww), suggesting HABs are an underappreciated and pervasive stressor to fish populations. Conversely, microcystin levels were consistently low in muscles (0-15 ng g-1 ww) and presented negligible risk, empirically supporting that fillets may be safely consumed before and after HAB events following fish consumption advisories.
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Affiliation(s)
- René S Shahmohamadloo
- School of Biological Sciences, Washington State University, 14204 NE Salmon Creek Ave, Vancouver, WA 98686, United States; School of Environmental Sciences, University of Guelph, 50 Stone Rd E, Guelph, ON N1G 2W1, Canada.
| | - Satyendra P Bhavsar
- Ministry of the Environment, Conservation and Parks, 125 Resources Rd, Toronto, ON M9P 3V6, Canada; Department of Physical & Environmental Sciences, University of Toronto, 1065 Military Trail, Toronto, ON M1C 1A4, Canada
| | - Xavier Ortiz Almirall
- Ministry of the Environment, Conservation and Parks, 125 Resources Rd, Toronto, ON M9P 3V6, Canada; IQS School of Engineering, Universitat Ramon Llull, Via Augusta, 390, 08017 Barcelona, Spain
| | - Stephen A C Marklevitz
- Lake Erie Management Unit, Ministry of Natural Resources and Forestry, 320 Milo Road, Wheatley, ON N0P 2P0, Canada
| | - Seth M Rudman
- School of Biological Sciences, Washington State University, 14204 NE Salmon Creek Ave, Vancouver, WA 98686, United States
| | - Paul K Sibley
- School of Environmental Sciences, University of Guelph, 50 Stone Rd E, Guelph, ON N1G 2W1, Canada
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23
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Yu J, Zhu H, Wang H, Shutes B, Niu T. Effect of butachlor on Microcystis aeruginosa: Cellular and molecular mechanisms of toxicity. JOURNAL OF HAZARDOUS MATERIALS 2023; 449:131042. [PMID: 36827725 DOI: 10.1016/j.jhazmat.2023.131042] [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: 10/17/2022] [Revised: 02/14/2023] [Accepted: 02/17/2023] [Indexed: 06/18/2023]
Abstract
The rapid development of agriculture increases the release of butachlor into aquatic environments. As a dominant species causing cyanobacterial blooms, Microcystis aeruginosa (M. aeruginosa) can produce microcystin and poses threats to aquatic ecosystems and human health. However, the impact of butachlor on M. aeruginosa remains unclarified. Therefore, the physiochemical responses of M. aeruginosa to butachlor were investigated, and the relevant underlying molecular mechanism was highlighted. There were no significant changes (P > 0.05) in the growth and physiology of M. aeruginosa at the low concentrations of butachlor (0-0.1 mg/L), which evidenced a high level of butachlor tolerance in Microcystis aeruginosa. For the high concentrations of butachlor (4-30 mg/L), the inhibition of photosynthetic activity, disruption of cell ultrastructure, and oxidative stress were dominant toxic effects on M. aeruginosa. Additionally, the impaired cellular integrity and lipid peroxidation may be attributed to the substantial elevations of extracellular microcystin-LR concentration. Downregulation of genes associated with photosynthesis, energy metabolism, and oxidative stress was inferred to be responsible for the growth suppression of M. aeruginosa in 30 mg/L butachlor treatment. The upregulation of gene sets involved in nitrogen metabolism may illustrate the specific effort to sustain the steady concentration of intracellular microcystin-LR. These findings dissect the response mechanism of M. aeruginosa to butachlor toxicity and provide valuable reference for the evaluation of potential risk caused by butachlor in aquatic environments.
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Affiliation(s)
- Jing Yu
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China; School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China
| | - Hui Zhu
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China; State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China.
| | - Heli Wang
- School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou University of Science and Technology, Suzhou, Jiangsu 215009, China
| | - Brian Shutes
- Department of Natural Sciences, Middlesex University, Hendon, London NW4 4BT, UK
| | - Tingting Niu
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
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24
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Gaëtan J, Halary S, Millet M, Bernard C, Duval C, Hamlaoui S, Hecquet A, Gugger M, Marie B, Mehta N, Moreira D, Skouri-Panet F, Travert C, Duprat E, Leloup J, Benzerara K. Widespread formation of intracellular calcium carbonates by the bloom-forming cyanobacterium Microcystis. Environ Microbiol 2023; 25:751-765. [PMID: 36550062 DOI: 10.1111/1462-2920.16322] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022]
Abstract
The formation of intracellular amorphous calcium carbonates (iACC) has been recently observed in a few cultured strains of Microcystis, a potentially toxic bloom-forming cyanobacterium found worldwide in freshwater ecosystems. If iACC-forming Microcystis are abundant within blooms, they may represent a significant amount of particulate Ca. Here, we investigate the significance of iACC biomineralization by Microcystis. First, the presence of iACC-forming Microcystis cells has been detected in several eutrophic lakes, indicating that this phenomenon occurs under environmental conditions. Second, some genotypic (presence/absence of ccyA, a marker gene of iACC biomineralization) and phenotypic (presence/absence of iACC) diversity have been detected within a collection of strains isolated from one single lake. This illustrates that this trait is frequent but also variable within Microcystis even at a single locality. Finally, one-third of publicly available genomes of Microcystis were shown to contain the ccyA gene, revealing a wide geographic and phylogenetic distribution within the genus. Overall, the present work shows that the formation of iACC by Microcystis is common under environmental conditions. While its biological function remains undetermined, this process should be further considered regarding the biology of Microcystis and implications on the Ca geochemical cycle in freshwater environments.
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Affiliation(s)
- Juliette Gaëtan
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS-SU-MNHN 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Paris, France
- Sorbonne Université, UMR 7618 CNRS-INRA-IRD-Paris 7-UPEC, Institut d'Ecologie et des Sciences de l'Environnement de Paris (iEES-Paris), Paris, France
| | - Sébastien Halary
- Muséum National d'Histoire Naturelle, UMR 7245 CNRS-MNHN, Molécules de Communication et Adaptation des Microorganismes, Paris, France
| | - Maxime Millet
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS-SU-MNHN 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Paris, France
| | - Cécile Bernard
- Muséum National d'Histoire Naturelle, UMR 7245 CNRS-MNHN, Molécules de Communication et Adaptation des Microorganismes, Paris, France
| | - Charlotte Duval
- Muséum National d'Histoire Naturelle, UMR 7245 CNRS-MNHN, Molécules de Communication et Adaptation des Microorganismes, Paris, France
| | - Sahima Hamlaoui
- Muséum National d'Histoire Naturelle, UMR 7245 CNRS-MNHN, Molécules de Communication et Adaptation des Microorganismes, Paris, France
| | - Amandine Hecquet
- Sorbonne Université, UMR 7618 CNRS-INRA-IRD-Paris 7-UPEC, Institut d'Ecologie et des Sciences de l'Environnement de Paris (iEES-Paris), Paris, France
| | - Muriel Gugger
- Institut Pasteur, Université Paris Cité, Collection of Cyanobacteria, Paris, France
| | - Benjamin Marie
- Muséum National d'Histoire Naturelle, UMR 7245 CNRS-MNHN, Molécules de Communication et Adaptation des Microorganismes, Paris, France
| | - Neha Mehta
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS-SU-MNHN 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Paris, France
| | - David Moreira
- Unité d'Ecologie Systématique et Evolution, CNRS, Université Paris-Saclay, AgroParisTech, Gif-sur-Yvette, France
| | - Fériel Skouri-Panet
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS-SU-MNHN 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Paris, France
| | - Cynthia Travert
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS-SU-MNHN 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Paris, France
| | - Elodie Duprat
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS-SU-MNHN 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Paris, France
| | - Julie Leloup
- Sorbonne Université, UMR 7618 CNRS-INRA-IRD-Paris 7-UPEC, Institut d'Ecologie et des Sciences de l'Environnement de Paris (iEES-Paris), Paris, France
| | - Karim Benzerara
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS-SU-MNHN 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Paris, France
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25
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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.
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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.
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26
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Ecological Dynamics of Broad- and Narrow-Host-Range Viruses Infecting the Bloom-Forming Toxic Cyanobacterium Microcystis aeruginosa. Appl Environ Microbiol 2023; 89:e0211122. [PMID: 36688685 PMCID: PMC9972985 DOI: 10.1128/aem.02111-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Microcystis aeruginosa is predicted to interact and coexist with diverse broad- and narrow-host-range viruses within a bloom; however, little is known about their affects on Microcystis population dynamics. Here, we developed a real-time PCR assay for the quantification of these viruses that have different host ranges. During the sampling period, total Microcystis abundance showed two peaks in May and August with a temporary decrease in June. The Microcystis population is largely divided into three phylotypes based on internal transcribed sequences (ITS; ITS types I to III). ITS I was the dominant phylotype (66% to 88%) except in June. Although the ITS II and III phylotypes were mostly less abundant, these phylotypes temporarily increased to approximately equivalent abundances of the ITS I population in June. During the same sampling period, the abundances of the broad-host-range virus MVGF_NODE331 increased from April to May and from July to October with a temporary decrease in June, in which its dynamics were in proportion to the increase of total Microcystis abundances regardless of changes in host ITS population composition. In contrast, the narrow-host-range viruses MVG_NODE620 and Ma-LMM01 were considerably less abundant than the broad-host-range virus and generally did not fluctuate in the environment. Considering that M. aeruginosa could increase the abundance and sustain the bloom under the prevalence of the broad-host-range virus, host abundant and diverse antiviral mechanisms might contribute to coexistence with its viruses. IMPORTANCE The bloom-forming toxic cyanobacterium Microcystis aeruginosa interacts with diverse broad- and narrow-host-range viruses. However, the dynamics of the Microcystis population (at the intraspecies level) and viruses with different host ranges remain unknown. Our real-time PCR assays unveiled that the broad-host-range virus gradually increased in abundance over the sampling period, in proportion to the increase in total Microcystis abundance regardless of changes in genotypic composition. The narrow-host-range viruses were considerably less abundant than the broad-host-range virus and did not generally fluctuate in the environment. The expansion and maintenance of the Microcystis bloom even under the increased infection by the broad-host-range virus suggested that highly abundant and diverse antiviral mechanisms allowed them to coexist with viruses under selective pressure. This paper expands our knowledge about the ecological dynamics of Microcystis viruses and provides potential insights into their coexistence with their host.
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27
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Cai H, McLimans CJ, Beyer JE, Krumholz LR, Hambright KD. Microcystis pangenome reveals cryptic diversity within and across morphospecies. SCIENCE ADVANCES 2023; 9:eadd3783. [PMID: 36638170 PMCID: PMC9839332 DOI: 10.1126/sciadv.add3783] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
Microcystis, a common harmful algal bloom (HAB) taxon, threatens water supplies and human health, yet species delimitation is contentious in this taxon, leading to challenges in research and management of this threat. Historical and common morphology-based classifications recognize multiple morphospecies, most with variable and diverse ecologies, while DNA sequence-based classifications indicate a single species with multiple ecotypes. To better delimit Microcystis species, we conducted a pangenome analysis of 122 genomes. Core- and non-core gene phylogenetic analyses placed 113 genomes into 23 monophyletic clusters containing at least two genomes. Overall, genome-related indices revealed that Microcystis contains at least 16 putative genospecies. Fifteen genospecies included at least one Microcystis aeruginosa morphospecies, and 10 genospecies included two or more morphospecies. This classification system will enable consistent taxonomic identification of Microcystis and thereby aid in resolving some of the complexities and controversies that have long characterized eco-evolutionary research and management of this important HAB taxon.
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Affiliation(s)
- Haiyuan Cai
- Plankton Ecology and Limnology Laboratory, Department of Biology, University of Oklahoma, Norman, OK, USA
| | - Christopher J. McLimans
- Plankton Ecology and Limnology Laboratory, Department of Biology, University of Oklahoma, Norman, OK, USA
- Program in Ecology and Evolutionary Biology, Department of Biology, University of Oklahoma, Norman, OK, USA
| | - Jessica E. Beyer
- Plankton Ecology and Limnology Laboratory, Department of Biology, University of Oklahoma, Norman, OK, USA
- Program in Ecology and Evolutionary Biology, Department of Biology, University of Oklahoma, Norman, OK, USA
| | - Lee R. Krumholz
- Department of Microbiology and Plant Biology and Institute for Energy and the Environment, University of Oklahoma, Norman, OK, USA
| | - K. David Hambright
- Plankton Ecology and Limnology Laboratory, Department of Biology, University of Oklahoma, Norman, OK, USA
- Program in Ecology and Evolutionary Biology, Department of Biology, University of Oklahoma, Norman, OK, USA
- Geographical Ecology, Department of Biology, University of Oklahoma, Norman, OK, USA
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28
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Zuo J, Tan F, Zhang H, Xue Y, Grossart HP, Jeppesen E, Xiao P, Chen H, Yang J. Interaction between Raphidiopsis raciborskii and rare bacterial species revealed by dilution-to-extinction experiments. HARMFUL ALGAE 2022; 120:102350. [PMID: 36470605 DOI: 10.1016/j.hal.2022.102350] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 10/31/2022] [Accepted: 11/06/2022] [Indexed: 06/17/2023]
Abstract
Interactions between heterotrophic bacteria and cyanobacteria regulate the structure and function of aquatic ecosystems and are thus crucial for the prediction and management of cyanobacterial blooms in relation to water security. Currently, abundant bacterial species are of primary concern, while the role of more diverse and copious rare species remains largely unknown. Using a dilution-to-extinction approach, rare bacterial species from reservoir water were co-cultured with the bloom-forming cyanobacterium Raphidiopsis raciborskii in the lab to explore their interactions by using Phyto-PAM and 16S rRNA gene high-throughput sequencing. We found that a ≤1000-fold bacterial dilution led to bacteria control of the growth and photosynthesis of R. raciborskii. Moreover, the bacterial community compositions in the low-dilution groups were clearly diverged from the high-dilution groups. Importantly, rare species changed dramatically in the low-dilution groups, resulting in lower phylogenetic diversity and narrower niche width. The network complexity and compositional stability of bacterial communities decreased in the low-dilution groups. Collectively, our results suggest that rare bacterial species inhibit R. raciborskii growth and photosynthesis through microbial interactions mediated by species coexistence and interaction mechanisms. Our study provides new knowledge of the ecological role of rare bacteria and offers new perspectives for understanding the outbreak and regression of R. raciborskii blooms.
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Affiliation(s)
- Jun Zuo
- Aquatic EcoHealth Group, Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Fengjiao Tan
- Aquatic EcoHealth Group, Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongteng Zhang
- Aquatic EcoHealth Group, Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuanyuan Xue
- Aquatic EcoHealth Group, Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Hans-Peter Grossart
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Stechlin 16775, Germany; University of Potsdam, Institute of Biochemistry and Biology, Potsdam 14469, Germany
| | - Erik Jeppesen
- Department of Ecoscience, Aarhus University, Aarhus 8000, Denmark; Sino-Danish Centre for Education and Research, Beijing 100049, China; Limnology Laboratory, Department of Biological Sciences and Centre for Ecosystem Research and Implementation, Middle East Technical University, Ankara 06800, Turkey; Institute of Marine Sciences, Middle East Technical University, Mersin 33731, Turkey
| | - Peng Xiao
- Aquatic EcoHealth Group, Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Huihuang Chen
- Aquatic EcoHealth Group, Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Yang
- Aquatic EcoHealth Group, Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
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29
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Painefilú JC, González C, Cárcamo JG, Bianchi VA, Luquet CM. Microcystin-LR modulates multixenobiotic resistance proteins in the middle intestine of rainbow trout, Oncorhynchus mykiss. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2022; 253:106327. [PMID: 36274501 DOI: 10.1016/j.aquatox.2022.106327] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 09/23/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
Abstract
Global climate change favors explosive population growth events (blooms) of phytoplanktonic species, often producing toxic products, e.g., several genera of cyanobacteria synthesize a family of cyanotoxins called microcystins (MCs). Freshwater fish such as the rainbow trout Oncorhynchus mykiss can uptake MCs accumulated in the food chain. We studied the toxic effects and modulation of the activity and expression of multixenobiotic resistance proteins (ABCC transporters and the enzyme glutathione S-transferase (GST) in the O. mykiss middle intestine by microcystin-LR (MCLR). Juvenile fish were fed with MCLR incorporated in the food every 12 h and euthanized at 12, 24, or 48 h. We estimated the ABCC-mediated transport in ex vivo intestinal strips to estimate ABCC-mediated transport activity. We measured total and reduced (GSH) glutathione contents and GST and glutathione reductase (GR) activities. We studied MCLR cytotoxicity by measuring protein phosphatase 1 (PP1) activity and lysosomal membrane stability. Finally, we examined the relationship between ROS production and lysosomal membrane stability through in vitro experiments. Dietary MCLR had a time-dependent effect on ABCC-mediated transport, from inhibition at 12 h to a significant increase after 48 h. GST activity decreased only at 12 h, and GR activity only increased at 48 h. There were no effects on GSH or total glutathione contents. MCLR inhibited PP1 activity and diminished the lysosomal membrane stability at the three experimental times. In the in vitro study, the lysosomal membrane stability decreased in a concentration-dependent fashion from 0 to 5 µmol L - 1 MCLR, while ROS production increased only at 5 µmol L - 1 MCLR. MCLR did not affect mRNA expression of abcc2 or gst-π. We conclude that MCLR modulates ABCC-mediated transport activity in O. mykiss's middle intestine in a time-dependent manner. The transport rate increase does not impair MCLR cytotoxic effects.
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Affiliation(s)
- Julio C Painefilú
- Laboratorio de Ictiología y Acuicultura Experimental, IPATEC (CONICET-UNCo). Quintral 1250. San Carlos de Bariloche, 8400, Río Negro, Argentina
| | - Carolina González
- Agua y Saneamientos Argentinos, Tucumán 752, 1049 Buenos Aires, Argentina; Laboratorio de Limnología, Facultad de Ciencias Exactas y Naturales, UBA, Argentina
| | - Juan G Cárcamo
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Campus Isla Teja, Valdivia, Chile; Centro FONDAP, Interdisciplinary Center for Aquaculture Research (INCAR), Chile
| | - Virginia A Bianchi
- Laboratorio de Ecotoxicología Acuática, Subsede INIBIOMA-CEAN (CONICET-UNCo). Ruta provincial 61, km 3, Junín de los Andes, 8371 Neuquén, Argentina
| | - Carlos M Luquet
- Laboratorio de Ecotoxicología Acuática, Subsede INIBIOMA-CEAN (CONICET-UNCo). Ruta provincial 61, km 3, Junín de los Andes, 8371 Neuquén, Argentina.
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30
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Heterotrophic Bacteria Dominate Catalase Expression during Microcystis Blooms. Appl Environ Microbiol 2022; 88:e0254421. [PMID: 35862723 PMCID: PMC9328184 DOI: 10.1128/aem.02544-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In the oligotrophic oceans, key autotrophs depend on "helper" bacteria to reduce oxidative stress from hydrogen peroxide (H2O2) in the extracellular environment. H2O2 is also a ubiquitous stressor in freshwaters, but the effects of H2O2 on autotrophs and their interactions with bacteria are less well understood in freshwaters. Naturally occurring H2O2 in freshwater systems is proposed to impact the proportion of microcystin-producing (toxic) and non-microcystin-producing (nontoxic) Microcystis in blooms, which influences toxin concentrations and human health impacts. However, how different strains of Microcystis respond to naturally occurring H2O2 concentrations and the microbes responsible for H2O2 decomposition in freshwater cyanobacterial blooms are unknown. To address these knowledge gaps, we used metagenomics and metatranscriptomics to track the presence and expression of genes for H2O2 decomposition by microbes during a cyanobacterial bloom in western Lake Erie in the summer of 2014. katG encodes the key enzyme for decomposing extracellular H2O2 but was absent in most Microcystis cells. katG transcript relative abundance was dominated by heterotrophic bacteria. In axenic Microcystis cultures, an H2O2 scavenger (pyruvate) significantly improved growth rates of one toxic strain while other toxic and nontoxic strains were unaffected. These results indicate that heterotrophic bacteria play a key role in H2O2 decomposition in Microcystis blooms and suggest that their activity may affect the fitness of some Microcystis strains and thus the strain composition of Microcystis blooms but not along a toxic versus nontoxic dichotomy. IMPORTANCE Cyanobacterial harmful algal blooms (CHABs) threaten freshwater ecosystems globally through the production of toxins. Toxin production by cyanobacterial species and strains during CHABs varies widely over time and space, but the ecological drivers of the succession of toxin-producing species remain unclear. Hydrogen peroxide (H2O2) is ubiquitous in natural waters, inhibits microbial growth, and may determine the relative proportions of Microcystis strains during blooms. However, the mechanisms and organismal interactions involved in H2O2 decomposition are unexplored in CHABs. This study shows that some strains of bloom-forming freshwater cyanobacteria benefit from detoxification of H2O2 by associated heterotrophic bacteria, which may impact bloom development.
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Uptake of Phytoplankton-Derived Carbon and Cobalamins by Novel Acidobacteria Genera in Microcystis Blooms Inferred from Metagenomic and Metatranscriptomic Evidence. Appl Environ Microbiol 2022; 88:e0180321. [PMID: 35862730 PMCID: PMC9317899 DOI: 10.1128/aem.01803-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Interactions between bacteria and phytoplankton can influence primary production, community composition, and algal bloom development. However, these interactions are poorly described for many consortia, particularly for freshwater bloom-forming cyanobacteria. Here, we assessed the gene content and expression of two uncultivated Acidobacteria from Lake Erie Microcystis blooms. These organisms were targeted because they were previously identified as important catalase producers in Microcystis blooms, suggesting that they protect Microcystis from H2O2. Metatranscriptomics revealed that both Acidobacteria transcribed genes for uptake of organic compounds that are known cyanobacterial products and exudates, including lactate, glycolate, amino acids, peptides, and cobalamins. Expressed genes for amino acid metabolism and peptide transport and degradation suggest that use of amino acids and peptides by Acidobacteria may regenerate nitrogen for cyanobacteria and other organisms. The Acidobacteria genomes lacked genes for biosynthesis of cobalamins but expressed genes for its transport and remodeling. This indicates that the Acidobacteria obtained cobalamins externally, potentially from Microcystis, which has a complete gene repertoire for pseudocobalamin biosynthesis; expressed them in field samples; and produced pseudocobalamin in axenic culture. Both Acidobacteria were detected in Microcystis blooms worldwide. Together, the data support the hypotheses that uncultured and previously unidentified Acidobacteria taxa exchange metabolites with phytoplankton during harmful cyanobacterial blooms and influence nitrogen available to phytoplankton. Thus, novel Acidobacteria may play a role in cyanobacterial physiology and bloom development. IMPORTANCE Interactions between heterotrophic bacteria and phytoplankton influence competition and successions between phytoplankton taxa, thereby influencing ecosystem-wide processes such as carbon cycling and algal bloom development. The cyanobacterium Microcystis forms harmful blooms in freshwaters worldwide and grows in buoyant colonies that harbor other bacteria in their phycospheres. Bacteria in the phycosphere and in the surrounding community likely influence Microcystis physiology and ecology and thus the development of freshwater harmful cyanobacterial blooms. However, the impacts and mechanisms of interaction between bacteria and Microcystis are not fully understood. This study explores the mechanisms of interaction between Microcystis and uncultured members of its phycosphere in situ with population genome resolution to investigate the cooccurrence of Microcystis and freshwater Acidobacteria in blooms worldwide.
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The Self-Bleaching Process of Microcystis aeruginosa is Delayed by a Symbiotic Bacterium Pseudomonas sp. MAE1-K and Promoted by Methionine Deficiency. Microbiol Spectr 2022; 10:e0181422. [PMID: 35771009 PMCID: PMC9430746 DOI: 10.1128/spectrum.01814-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Various interactions between marine cyanobacteria and heterotrophic bacteria have been known, but the symbiotic relationships between Microcystis and heterotrophic bacteria remain unclear. An axenic M. aeruginosa culture (NIES-298) was quickly bleached after exponential growth, whereas a xenic M. aeruginosa culture (KW) showed a normal growth curve, suggesting that some symbiotic bacteria may delay this bleaching. The bleaching process of M. aeruginosa was distinguished from the phenomena of previously proposed chlorosis and programmed cell death in various characteristics. Bleached cultures of NIES-298 quickly bleached actively growing M. aeruginosa cultures, suggesting that M. aeruginosa itself produces bleach-causing compounds. Pseudomonas sp. MAE1-K delaying the bleaching of NIES-298 cultures was isolated from the KW culture. Bleached cultures of NIES-298 treated with strain MAE1-K lost their bleaching ability, suggesting that strain MAE1-K rescues M. aeruginosa from bleaching via inactivation of bleaching compounds. From Tn5 transposon mutant screening, a metZ mutant of strain MAE1-K (F-D3) unable to synthesize methionine, promoting the bleaching of NIES-298 cultures but capable of inactivating bleaching compounds, was obtained. The bleaching process of NIES-298 cultures was promoted with the coculture of mutant F-D3 and delayed by methionine supplementation, suggesting that the bleaching process of M. aeruginosa is promoted by methionine deficiency. IMPORTANCE Cyanobacterial blooms in freshwaters represent serious global concerns for the ecosystem and human health. In this study, we found that one of the major species in cyanobacterial blooms, Microcystis aeruginosa, was quickly collapsed after exponential growth by producing self-bleaching compounds and that a symbiotic bacterium, Pseudomonas sp. MAE1-K delayed the bleaching process via the inactivation of bleaching compounds. In addition, we found that a metZ mutant of strain MAE1-K (F-D3) causing methionine deficiency promoted the bleaching process of M. aeruginosa, suggesting that methionine deficiency may induce the production of bleaching compounds. These results will provide insights into the symbiotic relationships between M. aeruginosa and heterotrophic bacteria that will contribute to developing novel strategies to control cyanobacterial blooms.
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Wang J, Wagner ND, Fulton JM, Scott JT. Dynamic Phycobilin Pigment Variations in Diazotrophic and Non-diazotrophic Cyanobacteria Batch Cultures Under Different Initial Nitrogen Concentrations. Front Microbiol 2022; 13:850997. [PMID: 35722313 PMCID: PMC9201475 DOI: 10.3389/fmicb.2022.850997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 04/26/2022] [Indexed: 11/15/2022] Open
Abstract
Increased anthropogenic nutrient loading has led to eutrophication of aquatic ecosystems, which is the major cause of harmful cyanobacteria blooms. Element stoichiometry of cyanobacteria bloom is subject to nutrient availabilities and may significantly contribute to primary production and biogeochemical cycling. Phycobilisome is the antenna of the photosynthetic pigment apparatus in cyanobacteria, which contains phycobilin pigments (PBPs) and linker proteins. This nitrogen (N)-rich protein complex has the potential to support growth as a N-storage site and may play a major role in the variability of cyanobacteria N stoichiometry. However, the regulation of PBPs during bloom formation remains unclear. We investigated the temporal variation of N allocation into PBPs and element stoichiometry for two ubiquitous cyanobacteria species, Microcystis aeruginosa and Dolichospermum flos-aquae, in a batch culture experiment with different initial N availabilities. Our results indicated that the N allocation into PBPs is species-dependent and tightly regulated by the availability of nutrients fueling population expansion. During the batch culture experiment, different nutrient uptake rates led to distinct stoichiometric imbalances of N and phosphorus (P), which substantially altered cyanobacteria C: N and C: P stoichiometry. Microcystis invested cellular N into PBPs and exhibited greater flexibility in C: N and C: P stoichiometry than D. flos-aquae. The dynamics of such N-rich macromolecules may help explain the N stoichiometry variation during a bloom and the interspecific difference between M. aeruginosa and D. flos-aquae. Our study provides a quantitative understanding of the elemental stoichiometry and the regulation of PBPs for non-diazotrophic and diazotrophic cyanobacteria blooms.
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Affiliation(s)
- Jingyu Wang
- The Institute of Ecological, Earth & Environmental Sciences, Baylor University, Waco, TX, United States
- *Correspondence: Jingyu Wang,
| | - Nicole D. Wagner
- Center for Reservoir and Aquatic Systems Research, Baylor University, Waco, TX, United States
| | - James M. Fulton
- Department of Geosciences, Baylor University, Waco, TX, United States
| | - J. Thad Scott
- The Institute of Ecological, Earth & Environmental Sciences, Baylor University, Waco, TX, United States
- Center for Reservoir and Aquatic Systems Research, Baylor University, Waco, TX, United States
- Department of Biology, Baylor University, Waco, TX, United States
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Hellweger FL, Martin RM, Eigemann F, Smith DJ, Dick GJ, Wilhelm SW. Models predict planned phosphorus load reduction will make Lake Erie more toxic. Science 2022; 376:1001-1005. [PMID: 35617400 DOI: 10.1126/science.abm6791] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Harmful cyanobacteria are a global environmental problem, yet we lack actionable understanding of toxigenic versus nontoxigenic strain ecology and toxin production. We performed a large-scale meta-analysis including 103 papers and used it to develop a mechanistic, agent-based model of Microcystis growth and microcystin production. Simulations for Lake Erie suggest that the observed toxigenic-to-nontoxigenic strain succession during the 2014 Toledo drinking water crisis was controlled by different cellular oxidative stress mitigation strategies (protection by microcystin versus degradation by enzymes) and the different susceptibility of those mechanisms to nitrogen limitation. This model, as well as a simpler empirical one, predicts that the planned phosphorus load reduction will lower biomass but make nitrogen and light more available, which will increase toxin production, favor toxigenic cells, and increase toxin concentrations.
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Affiliation(s)
- Ferdi L Hellweger
- Water Quality Engineering, Technical University of Berlin, Berlin, Germany
| | - Robbie M Martin
- Department of Microbiology, University of Tennessee, Knoxville, TN, USA
| | - Falk Eigemann
- Water Quality Engineering, Technical University of Berlin, Berlin, Germany
| | - Derek J Smith
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Gregory J Dick
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA.,Cooperative Institute for Great Lakes Research, University of Michigan, Ann Arbor, MI, USA
| | - Steven W Wilhelm
- Department of Microbiology, University of Tennessee, Knoxville, TN, USA
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Yancey CE, Smith DJ, Den Uyl PA, Mohamed OG, Yu F, Ruberg SA, Chaffin JD, Goodwin KD, Tripathi A, Sherman DH, Dick GJ. Metagenomic and Metatranscriptomic Insights into Population Diversity of Microcystis Blooms: Spatial and Temporal Dynamics of mcy Genotypes, Including a Partial Operon That Can Be Abundant and Expressed. Appl Environ Microbiol 2022; 88:e0246421. [PMID: 35438519 PMCID: PMC9088275 DOI: 10.1128/aem.02464-21] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 03/14/2022] [Indexed: 11/29/2022] Open
Abstract
Cyanobacterial harmful algal blooms (cyanoHABs) degrade freshwater ecosystems globally. Microcystis aeruginosa often dominates cyanoHABs and produces microcystin (MC), a class of hepatotoxins that poses threats to human and animal health. Microcystin toxicity is influenced by distinct structural elements across a diversity of related molecules encoded by variant mcy operons. However, the composition and distribution of mcy operon variants in natural blooms remain poorly understood. Here, we characterized the variant composition of mcy genes in western Lake Erie Microcystis blooms from 2014 and 2018. Sampling was conducted across several spatial and temporal scales, including different bloom phases within 2014, extensive spatial coverage on the same day (2018), and frequent, autonomous sampling over a 2-week period (2018). Mapping of metagenomic and metatranscriptomic sequences to reference sequences revealed three Microcystis mcy genotypes: complete (all genes present [mcyA-J]), partial (truncated mcyA, complete mcyBC, and missing mcyD-J), and absent (no mcy genes). We also detected two different variants of mcyB that may influence the production of microcystin congeners. The relative abundance of these genotypes was correlated with pH and nitrate concentrations. Metatranscriptomic analysis revealed that partial operons were, at times, the most abundant genotype and expressed in situ, suggesting the potential biosynthesis of truncated products. Quantification of genetic divergence between genotypes suggests that the observed strains are the result of preexisting heterogeneity rather than de novo mutation during the sampling period. Overall, our results show that natural Microcystis populations contain several cooccurring mcy genotypes that dynamically shift in abundance spatiotemporally via strain succession and likely influence the observed diversity of the produced congeners. IMPORTANCE Cyanobacteria are responsible for producing microcystins (MCs), a class of potent and structurally diverse toxins, in freshwater systems around the world. While microcystins have been studied for over 50 years, the diversity of their chemical forms and how this variation is encoded at the genetic level remain poorly understood, especially within natural populations of cyanobacterial harmful algal blooms (cyanoHABs). Here, we leverage community DNA and RNA sequences to track shifts in mcy genes responsible for producing microcystin, uncovering the relative abundance, expression, and variation of these genes. We studied this phenomenon in western Lake Erie, which suffers annually from cyanoHAB events, with impacts on drinking water, recreation, tourism, and commercial fishing.
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Affiliation(s)
- Colleen E. Yancey
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan, USA
| | - Derek J. Smith
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan, USA
| | - Paul A. Den Uyl
- Cooperative Institute for Great Lakes Research (CIGLR), University of Michigan, Ann Arbor, Michigan, USA
| | - Osama G. Mohamed
- Natural Products Discovery Core, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
- Life Science Institute, University of Michigan, Ann Arbor, Michigan, USA
- Pharmacognosy Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Fengan Yu
- Life Science Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Steven A. Ruberg
- National Oceanic and Atmospheric Administration (NOAA) Great Lakes Environmental Research Laboratory, Ann Arbor, Michigan, USA
| | - Justin D. Chaffin
- F. T. Stone Laboratory, The Ohio State University, Put-In-Bay, Ohio, USA
- Ohio Sea Grant, The Ohio State University, Put-In-Bay, Ohio, USA
| | - Kelly D. Goodwin
- Ocean Chemistry and Ecosystems Division, Atlantic Oceanographic and Meteorological Laboratory (AOML), NOAA, Miami, Florida, USA
- Southwest Fisheries Science Center, NOAA, La Jolla, California, USA
| | - Ashootosh Tripathi
- Natural Products Discovery Core, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
- Life Science Institute, University of Michigan, Ann Arbor, Michigan, USA
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - David H. Sherman
- Life Science Institute, University of Michigan, Ann Arbor, Michigan, USA
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Gregory J. Dick
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan, USA
- Cooperative Institute for Great Lakes Research (CIGLR), University of Michigan, Ann Arbor, Michigan, USA
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Shahmohamadloo RS, Ortiz Almirall X, Simmons DBD, Poirier DG, Bhavsar SP, Sibley PK. Fish tissue accumulation and proteomic response to microcystins is species-dependent. CHEMOSPHERE 2022; 287:132028. [PMID: 34474382 DOI: 10.1016/j.chemosphere.2021.132028] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 08/20/2021] [Accepted: 08/24/2021] [Indexed: 06/13/2023]
Abstract
Cyanotoxins including microcystins are increasing globally, escalating health risks to humans and wildlife. Freshwater fish can accumulate and retain microcystins in tissues; however, uptake and depuration studies thus far have not exposed fish to microcystins in its intracellular state (i.e., cell-bound or conserved within cyanobacteria), which is a primary route of exposure in the field, nor have they investigated sublethal molecular-level effects in tissues, limiting our knowledge of proteins responsible for microcystin toxicity pathways in pre-to-postsenescent stages of a harmful algal bloom. We address these gaps with a 2-wk study (1 wk of 'uptake' exposure to intracellular microcystins (0-40 μg L-1) produced by Microcystis aeruginosa followed by 1 wk of 'depuration' in clean water) using Rainbow Trout (Oncorhynchus mykiss) and Lake Trout (Salvelinus namaycush). Liver and muscle samples were collected throughout uptake and depuration phases for targeted microcystin quantification and nontargeted proteomics. For both species, microcystins accumulated at a higher concentration in the liver than muscle, and activated cellular responses related to oxidative stress, apoptosis, DNA repair, and carcinogenicity. However, intraspecific proteomic effects between Rainbow Trout and Lake Trout differed, and interspecific accumulation and retention of microcystins in tissues within each species also differed. We demonstrate that fish do not respond the same to cyanobacterial toxicity within and among species despite being reared in the same environment and diet.
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Affiliation(s)
- René S Shahmohamadloo
- School of Environmental Sciences, University of Guelph, Guelph, Ontario, Canada; Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada.
| | - Xavier Ortiz Almirall
- Ministry of the Environment, Conservation and Parks, Toronto, Ontario, Canada; School of Environmental Studies, Queen's University, Kingston, Ontario, Canada
| | | | - David G Poirier
- Ministry of the Environment, Conservation and Parks, Toronto, Ontario, Canada
| | - Satyendra P Bhavsar
- Ministry of the Environment, Conservation and Parks, Toronto, Ontario, Canada; Department of Physical & Environmental Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Paul K Sibley
- School of Environmental Sciences, University of Guelph, Guelph, Ontario, Canada
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