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Wei N, Hu C, Dittmann E, Song L, Gan N. The biological functions of microcystins. WATER RESEARCH 2024; 262:122119. [PMID: 39059200 DOI: 10.1016/j.watres.2024.122119] [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: 05/21/2024] [Revised: 07/16/2024] [Accepted: 07/17/2024] [Indexed: 07/28/2024]
Abstract
Microcystins are potent hepatotoxins predominantly produced by bloom-forming freshwater cyanobacteria (e.g., Microcystis, Planktothrix, Dolichospermum). Microcystin biosynthesis involves large multienzyme complexes and tailoring enzymes encoded by the mcy gene cluster. Mutation, recombination, and deletion events have shaped the mcy gene cluster in the course of evolution, resulting in a large diversity of microcystin congeners and the natural coexistence of toxic and non-toxic strains. The biological functions of microcystins and their association with algal bloom formation have been extensively investigated over the past decades. This review synthesizes recent advances in decoding the biological role of microcystins in carbon/nitrogen metabolism, antioxidation, colony formation, and cell-to-cell communication. Microcystins appear to adopt multifunctional roles in cyanobacteria that reflect the adaptive plasticity of toxic cyanobacteria to changing environments.
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Affiliation(s)
- Nian Wei
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China
| | - Chenlin Hu
- College of Pharmacy, University of Houston, Houston, TX 77204, USA
| | - Elke Dittmann
- Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam-Golm, Germany
| | - Lirong Song
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Nanqin Gan
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
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Yancey CE, Hart L, Hefferan S, Mohamed OG, Newmister SA, Tripathi A, Sherman DH, Dick GJ. Metabologenomics reveals strain-level genetic and chemical diversity of Microcystis secondary metabolism. mSystems 2024; 9:e0033424. [PMID: 38916306 PMCID: PMC11264947 DOI: 10.1128/msystems.00334-24] [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: 03/08/2024] [Accepted: 04/22/2024] [Indexed: 06/26/2024] Open
Abstract
Microcystis spp. are renowned for producing the hepatotoxin microcystin in freshwater cyanobacterial harmful algal blooms around the world, threatening drinking water supplies and public and environmental health. However, Microcystis genomes also harbor numerous biosynthetic gene clusters (BGCs) encoding the biosynthesis of other secondary metabolites, including many with toxic properties. Most of these BGCs are uncharacterized and currently lack links to biosynthesis products. However, recent field studies show that many of these BGCs are abundant and transcriptionally active in natural communities, suggesting potentially important yet unknown roles in bloom ecology and water quality. Here, we analyzed 21 xenic Microcystis cultures isolated from western Lake Erie to investigate the diversity of the biosynthetic potential of this genus. Through metabologenomic and in silico approaches, we show that these Microcystis strains contain variable BGCs, previously observed in natural populations, and encode distinct metabolomes across cultures. Additionally, we find that the majority of metabolites and gene clusters are uncharacterized, highlighting our limited understanding of the chemical repertoire of Microcystis spp. Due to the complex metabolomes observed in culture, which contain a wealth of diverse congeners as well as unknown metabolites, these results underscore the need to deeply explore and identify secondary metabolites produced by Microcystis beyond microcystins to assess their impacts on human and environmental health.IMPORTANCEThe genus Microcystis forms dense cyanobacterial harmful algal blooms (cyanoHABs) and can produce the toxin microcystin, which has been responsible for drinking water crises around the world. While microcystins are of great concern, Microcystis also produces an abundance of other secondary metabolites that may be of interest due to their potential for toxicity, ecological importance, or pharmaceutical applications. In this study, we combine genomic and metabolomic approaches to study the genes responsible for the biosynthesis of secondary metabolites as well as the chemical diversity of produced metabolites in Microcystis strains from the Western Lake Erie Culture Collection. This unique collection comprises Microcystis strains that were directly isolated from western Lake Erie, which experiences substantial cyanoHAB events annually and has had negative impacts on drinking water, tourism, and industry.
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Affiliation(s)
- Colleen E. Yancey
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan, USA
| | - Lauren Hart
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Sierra Hefferan
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan, USA
- Departments of Medicinal Chemistry, Chemistry, Microbiology, and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Osama G. Mohamed
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
- Natural Products Discovery Core, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
- Pharmacognosy Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Sean A. Newmister
- 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, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
- Pharmacognosy Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - David H. Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
- Departments of Medicinal Chemistry, Chemistry, Microbiology, and Immunology, University of Michigan, Ann Arbor, Michigan, USA
- Pharmacognosy Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Gregory J. Dick
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan, USA
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan, USA
- Cooperative Institute for Great Lakes Research (CIGLR), School for Environment and Sustainability, University of Michigan, Ann Arbor, Michigan, USA
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Reignier O, Bormans M, Hervé F, Robert E, Savar V, Tanniou S, Amzil Z, Noël C, Briand E. Spatio-temporal connectivity of a toxic cyanobacterial community and its associated microbiome along a freshwater-marine continuum. HARMFUL ALGAE 2024; 134:102627. [PMID: 38705620 DOI: 10.1016/j.hal.2024.102627] [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: 01/26/2024] [Revised: 03/22/2024] [Accepted: 04/10/2024] [Indexed: 05/07/2024]
Abstract
Due to climate changes and eutrophication, blooms of predominantly toxic freshwater cyanobacteria are intensifying and are likely to colonize estuaries, thus impacting benthic organisms and shellfish farming representing a major ecological, health and economic risk. In the natural environment, Microcystis form large mucilaginous colonies that influence the development of both cyanobacterial and embedded bacterial communities. However, little is known about the fate of natural colonies of Microcystis by salinity increase. In this study, we monitored the fate of a Microcystis dominated bloom and its microbiome along a French freshwater-marine gradient at different phases of a bloom. We demonstrated changes in the cyanobacterial genotypic composition, in the production of specific metabolites (toxins and compatible solutes) and in the heterotrophic bacteria structure in response to the salinity increase. In particular M. aeruginosa and M. wesenbergii survived salinities up to 20. Based on microcystin gene abundance, the cyanobacteria became more toxic during their estuarine transfer but with no selection of specific microcystin variants. An increase in compatible solutes occurred along the continuum with extensive trehalose and betaine accumulations. Salinity structured most the heterotrophic bacteria community, with an increased in the richness and diversity along the continuum. A core microbiome in the mucilage-associated attached fraction was highly abundant suggesting a strong interaction between Microcystis and its microbiome and a likely protecting role of the mucilage against an osmotic shock. These results underline the need to better determine the interactions between the Microcystis colonies and their microbiome as a likely key to their widespread success and adaptation to various environmental conditions.
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Affiliation(s)
| | - Myriam Bormans
- UMR CNRS 6553 ECOBIO, University of Rennes 1, Rennes F-35042, France
| | - Fabienne Hervé
- IFREMER, PHYTOX, Laboratoire METALG, Nantes F-44000, France
| | - Elise Robert
- IFREMER, PHYTOX, Laboratoire GENALG, Nantes F-44000, France
| | | | - Simon Tanniou
- IFREMER, PHYTOX, Laboratoire METALG, Nantes F-44000, France
| | - Zouher Amzil
- IFREMER, PHYTOX, Laboratoire METALG, Nantes F-44000, France
| | - Cyril Noël
- IFREMER, IRSI - Service de Bioinformatique (SeBiMER), Plouzané, France
| | - Enora Briand
- IFREMER, PHYTOX, Laboratoire GENALG, Nantes F-44000, France.
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4
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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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Rzodkiewicz LD, Turcotte MM. Two duckweed species exhibit variable tolerance to microcystin-LR exposure across genotypic lineages. HARMFUL ALGAE 2024; 131:102548. [PMID: 38212081 DOI: 10.1016/j.hal.2023.102548] [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: 08/01/2023] [Revised: 11/17/2023] [Accepted: 11/21/2023] [Indexed: 01/13/2024]
Abstract
Cyanotoxins produced by harmful cyanobacteria blooms can damage freshwater ecosystems and threaten human health. Floating macrophytes may be used as a means of biocontrol by limiting light and resources available to cyanobacteria. However, genetic variation in macrophyte sensitivity to cyanotoxins could influence their suitability as biocontrol agents. We investigated the influence of such intraspecific variation on the response of two rapidly growing duckweed species, Lemna minor and Spirodela polyrhiza, often used in nutrient and metal bioremediation. We assessed two biomarkers related to productivity (biomass and chlorophyll A production) and two related to fitness measures (population size and growth rate). Fifteen genetic lineages of each species were grown in media containing common cyanotoxin microcystin-LR at ecologically relevant concentrations or control media for a period of twelve days. Genotype identity had a strong impact on all biomarker responses. Microcystin concentration slightly increased the final population sizes of both macrophyte species with a marginal effect on growth rate of L. minor and the chlorophyll A production of S. polyrhiza, but overall these species were very tolerant of microcystin. The strong tolerance supports the potential use of these plants as bioremediators of cyanobacterial blooms. However, differential impact of microcystin exposure discovered in single lineage models among genotypes indicates a potential for cyanotoxins to act as selective forces, necessitating attention to genotype selection for bioremediation.
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Affiliation(s)
- Lacey D Rzodkiewicz
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, 15260, Pennsylvania, United States of America.
| | - Martin M Turcotte
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, 15260, Pennsylvania, United States of America
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Feng M, Hu Y, Yang L, Wu J, Yang G, Jian S, Hu B, Wen C. GST-Mu of Cristaria plicata is regulated by Nrf2/Keap1 pathway in detoxification microcystin and has antioxidant function. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2023; 263:106708. [PMID: 37776712 DOI: 10.1016/j.aquatox.2023.106708] [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: 07/07/2023] [Revised: 09/21/2023] [Accepted: 09/24/2023] [Indexed: 10/02/2023]
Abstract
Glutathione S-transferase is a crucial phase II metabolic enzyme involved in detoxification and metabolism in aquatic organisms. This study aimed to investigate the regulation of Nrf2/Keap1 pathway on microcystin-induced CpGST-Mu expression and CpGST-Mu resistance to hydrogen peroxide. A mu class GST from Cristaria plicata (CpGST-Mu) was identified. The full-length cDNA was 1026 bp, with an open reading frame of 558 bp. Subcellular localization revealed that CpGST-Mu was localized in cytoplasm. The optimum pH and temperature for the catalytic activity of CpGST-Mu protein was pH 6 and 40 °C, respectively. The results of Real-time quantitative PCR showed that CpGST-Mu mRNA was constitutively expressed in tissues, with the highest expression level in hepatopancreas and the lowest expression level in gill. The mRNA level of CpGST-Mu was significantly increased under the stress of microcystins and hydrogen peroxide. CpGST-Mu had an antagonistic effect on hydrogen peroxide. In the knockdown experiments, the mRNA levels of CpGST-Mu exhibited corresponding changes while Nrf2 and Keap1 genes were individually knocked down. These findings indicated that GST-Mu exhibited antioxidant properties and its expression was regulated by Nrf2/Keap1 signaling pathway. The study provided new information on the function of GST-Mu and could contribute to future studies on how to excrete microcystins in molluscs.
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Affiliation(s)
- Maolin Feng
- College of Life Science, Education Ministry Key Laboratory of Poyang Lake Environment and Resource Utilization, Nanchang University, Nanchang 330031, China
| | - Yile Hu
- College of Life Science, Education Ministry Key Laboratory of Poyang Lake Environment and Resource Utilization, Nanchang University, Nanchang 330031, China
| | - Lang Yang
- College of Life Science, Education Ministry Key Laboratory of Poyang Lake Environment and Resource Utilization, Nanchang University, Nanchang 330031, China
| | - Jielian Wu
- Jiangxi Science and Technology Normal University, Nanchang, Jiangxi Province, 11318, China
| | - Gang Yang
- College of Life Science, Education Ministry Key Laboratory of Poyang Lake Environment and Resource Utilization, Nanchang University, Nanchang 330031, China
| | - Shaoqing Jian
- College of Life Science, Education Ministry Key Laboratory of Poyang Lake Environment and Resource Utilization, Nanchang University, Nanchang 330031, China
| | - Baoqing Hu
- College of Life Science, Education Ministry Key Laboratory of Poyang Lake Environment and Resource Utilization, Nanchang University, Nanchang 330031, China.
| | - Chungen Wen
- College of Life Science, Education Ministry Key Laboratory of Poyang Lake Environment and Resource Utilization, Nanchang University, Nanchang 330031, China.
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Chaffin JD, Westrick JA, Reitz LA, Bridgeman TB. Microcystin congeners in Lake Erie follow the seasonal pattern of nitrogen availability. HARMFUL ALGAE 2023; 127:102466. [PMID: 37544667 PMCID: PMC10867787 DOI: 10.1016/j.hal.2023.102466] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 05/01/2023] [Accepted: 05/31/2023] [Indexed: 08/08/2023]
Abstract
Cyanobacteria harmful algal blooms produce many toxic secondary metabolites called cyanotoxins. The most studied group of cyanotoxins are microcystins (MC), with over 300 congeners reported. MC-LR is the most studied congener because of its abundance and toxicity. Recent toxicology studies suggest that more hydrophobic MC congeners such as MC-LA, MC-LF, and MC-LW may be less abundant but up to seven times more toxic than MC-LR, whereas, MC-RR's toxicity is only one-fifth that of MC-LR. Hence, understanding the environmental stressors that change the MC congener profile is critical to assessing the negative impact on environmental and human health. A two-year field and experimental study investigated seasonal and spatial changes of MC congener profiles in the western basin of Lake Erie. Both studies showed that nitrogen enrichment favored the production of nitrogen-rich MC-RR (C49H75N13O12). The field study showed that nitrogen depletion favored the low-nitrogen MC-LA (C46H67N7O12). MC-LR (a medium N level, C49H75N10O12) accounted for ∼30% to 50% of the total MC concentration and was stable across nitrogen concentrations. Using the relative toxicity and concentrations of each MC congener, both LC-MS/MS and ELISA overestimated the toxicity early bloom (July) and underestimated it late bloom (September). On 24 July 2019, highly toxic MC-LW and MC-LF were detected at nearshore stations with relative toxicity exceeding drinking water standards. This study demonstrated that the less toxic, high nitrogen MC-RR dominated under nitrogen-replete conditions in the early season, whereas the more toxic, less nitrogen MC-LA dominated under nitrogen-limited conditions later in the season.
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Affiliation(s)
- Justin D Chaffin
- F.T. Stone Laboratory and Ohio Sea Grant, The Ohio State University, 878 Bayview Ave. P.O. Box 119, Put-In-Bay, OH 43456, USA.
| | - Judy A Westrick
- Lumigen Instrument Center, Wayne State University, 5101 Cass Ave, Detroit, MI 48202, USA
| | - Laura A Reitz
- Department of Biological Sciences, Bowling Green State University, Life Sciences Building, Bowling Green, OH 43402, USA
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Yancey CE, Kiledal EA, Chaganti SR, Denef VJ, Errera RM, Evans JT, Hart LN, Isailovic D, James WS, Kharbush JJ, Kimbrel JA, Li W, Mayali X, Nitschky H, Polik CA, Powers MA, Premathilaka SH, Rappuhn NA, Reitz LA, Rivera SR, Zwiers CC, Dick GJ. The Western Lake Erie culture collection: A promising resource for evaluating the physiological and genetic diversity of Microcystis and its associated microbiome. HARMFUL ALGAE 2023; 126:102440. [PMID: 37290887 DOI: 10.1016/j.hal.2023.102440] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 04/24/2023] [Accepted: 04/28/2023] [Indexed: 06/10/2023]
Abstract
Cyanobacterial harmful algal blooms (cyanoHABs) dominated by Microcystis spp. have significant public health and economic implications in freshwater bodies around the world. These blooms are capable of producing a variety of cyanotoxins, including microcystins, that affect fishing and tourism industries, human and environmental health, and access to drinking water. In this study, we isolated and sequenced the genomes of 21 primarily unialgal Microcystis cultures collected from western Lake Erie between 2017 and 2019. While some cultures isolated in different years have a high degree of genetic similarity (genomic Average Nucleotide Identity >99%), genomic data show that these cultures also represent much of the breadth of known Microcystis diversity in natural populations. Only five isolates contained all the genes required for microcystin biosynthesis while two isolates contained a previously described partial mcy operon. Microcystin production within cultures was also assessed using Enzyme-Linked Immunosorbent Assay (ELISA) and supported genomic results with high concentrations (up to 900 μg L⁻¹) in cultures with complete mcy operons and no or low toxin detected otherwise. These xenic cultures also contained a substantial diversity of bacteria associated with Microcystis, which has become increasingly recognized as an essential component of cyanoHAB community dynamics. These results highlight the genomic diversity among Microcystis strains and associated bacteria in Lake Erie, and their potential impacts on bloom development, toxin production, and toxin degradation. This culture collection significantly increases the availability of environmentally relevant Microcystis strains from temperate North America.
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Affiliation(s)
- Colleen E Yancey
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - E Anders Kiledal
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Subba Rao Chaganti
- Cooperative Institute for Great Lakes Research (CIGLR), University of Michigan, 4840 S State Road, Ann Arbor, MI 48108, United States of America
| | - Vincent J Denef
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Reagan M Errera
- National Oceanic and Atmospheric Administration (NOAA), Great Lakes Environmental Research Laboratory (GLERL), 4840 S State Road, Ann Arbor, MI 48108, United States of America
| | - Jacob T Evans
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Lauren N Hart
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109, United States of America; Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Dragan Isailovic
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, United States of America
| | - William S James
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Jenan J Kharbush
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Jeffrey A Kimbrel
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States of America
| | - Wei Li
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States of America
| | - Xavier Mayali
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States of America
| | - Helena Nitschky
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Catherine A Polik
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - McKenzie A Powers
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Sanduni H Premathilaka
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH 43606, United States of America
| | - Nicole A Rappuhn
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Laura A Reitz
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Sara R Rivera
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Claire C Zwiers
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Gregory J Dick
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States of America; Cooperative Institute for Great Lakes Research (CIGLR), University of Michigan, 4840 S State Road, Ann Arbor, MI 48108, United States of America.
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9
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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: 1] [Impact Index Per Article: 1.0] [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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Chen J, Zhang T, Sun L, Liu Y, Li D, Leng X, An S. Abundance trade-offs and dominant taxa maintain the stability of the bacterioplankton community underlying Microcystis blooms. Front Microbiol 2023; 14:1181341. [PMID: 37275174 PMCID: PMC10235547 DOI: 10.3389/fmicb.2023.1181341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/09/2023] [Indexed: 06/07/2023] Open
Abstract
Microcystis blooms are an intractable global environmental problem that pollute water and compromise ecosystem functioning. Closed-lake management practices keep lakes free of sewage and harmful algae invasions and have succeeded in controlling local Microcystis blooms; however, there is little understanding of how the bacterioplankton communities associated with Microcystis have changed. Here, based on metagenomic sequencing, the phyla, genera, functional genes and metabolic functions of the bacterioplankton communities were compared between open lakes (underlying Microcystis blooms) and closed lakes (no Microcystis blooms). Water properties and zooplankton density were investigated and measured as factors influencing blooms. The results showed that (1) the water quality of closed lakes was improved, and the nitrogen and phosphorus concentrations were significantly reduced. (2) The stability of open vs. closed-managed lakes differed notably at the species and genus levels (p < 0.01), but no significant variations were identified at the phylum and functional genes levels (p > 0.05). (3) The relative abundance of Microcystis (Cyanobacteria) increased dramatically in the open lakes (proportions from 1.44 to 41.76%), whereas the relative abundance of several other dominant genera of Cyanobacteria experienced a trade-off and decreased with increasing Microcystis relative abundance. (4) The main functions of the bacterioplankton communities were primarily related to dominant genera of Proteobacteria and had no significant relationship with Microcystis. Overall, the closed-lake management practices significantly reduced nutrients and prevented Microcystis blooms, but the taxonomic and functional structures of bacterioplankton communities remained stable overall.
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Affiliation(s)
- Jun Chen
- School of Life Science and Institute of Wetland Ecology, Nanjing University, Nanjing, China
- Nanjing University Ecology Research Institute of Changshu (NJUecoRICH), Changshu, China
| | - Tiange Zhang
- School of Life Science and Institute of Wetland Ecology, Nanjing University, Nanjing, China
- Nanjing University Ecology Research Institute of Changshu (NJUecoRICH), Changshu, China
| | - Lingyan Sun
- School of Life Science and Institute of Wetland Ecology, Nanjing University, Nanjing, China
- Nanjing University Ecology Research Institute of Changshu (NJUecoRICH), Changshu, China
| | - Yan Liu
- School of Life Science and Institute of Wetland Ecology, Nanjing University, Nanjing, China
- Nanjing University Ecology Research Institute of Changshu (NJUecoRICH), Changshu, China
| | - Dianpeng Li
- School of Life Science and Institute of Wetland Ecology, Nanjing University, Nanjing, China
- Nanjing University Ecology Research Institute of Changshu (NJUecoRICH), Changshu, China
| | - Xin Leng
- School of Life Science and Institute of Wetland Ecology, Nanjing University, Nanjing, China
- Nanjing University Ecology Research Institute of Changshu (NJUecoRICH), Changshu, China
| | - Shuqing An
- School of Life Science and Institute of Wetland Ecology, Nanjing University, Nanjing, China
- Nanjing University Ecology Research Institute of Changshu (NJUecoRICH), Changshu, China
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11
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Yancey CE, Mathiesen O, Dick GJ. Transcriptionally active nitrogen fixation and biosynthesis of diverse secondary metabolites by Dolichospermum and Aphanizomenon-like Cyanobacteria in western Lake Erie Microcystis blooms. HARMFUL ALGAE 2023; 124:102408. [PMID: 37164563 DOI: 10.1016/j.hal.2023.102408] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 02/15/2023] [Accepted: 02/17/2023] [Indexed: 05/12/2023]
Abstract
Cyanobacterial harmful algal blooms (cyanoHABs) in the western basin of Lake Erie are dominated by microcystin producing Microcystis spp., but other cyanobacterial taxa that coexist in these communities may play important roles in production of toxins and shaping bloom dynamics and community function. In this study, we used metagenomic and metatranscriptomic data from the 2014 western Lake Erie cyanoHAB to explore the genetic diversity and biosynthetic potential of cyanobacteria belonging to the Anabaena, Dolichospermum, Aphanizomenon (ADA) clade. We reconstructed two near-complete metagenome-assembled genomes from two distinct ADA clade species, each containing biosynthetic gene clusters that encode novel and known secondary metabolites, including those with toxic and/or known taste and odor properties, that were transcriptionally active. However, neither ADA metagenome-assembled genome contained genes encoding guanitoxins, anatoxins, or saxitoxins, which are known to be produced by ADA. The ADA cyanobacteria accounted for most of the metagenomic and metatranscriptomic reads from nitrogen fixation genes, suggesting they were the dominant N-fixers at the times and stations sampled. Despite their relatively low abundance, our results highlight the possibility that ADA taxa could influence the water quality and ecology of Microcystis blooms, although the extent of these impacts remains to be quantified.
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Affiliation(s)
- Colleen E Yancey
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, 48109, USA
| | - Olivia Mathiesen
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, 48109, USA
| | - Gregory J Dick
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, 48109, USA; Cooperative Institute for Great Lakes Research (CIGLR), University of Michigan, 4840 South State Road, Ann Arbor, MI 48108 USA.
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12
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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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13
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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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14
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Abstract
Common culturing techniques and priorities bias our discovery towards specific traits that may not be representative of microbial diversity in nature. So far, these biases have not been systematically examined. To address this gap, here we use 116,884 publicly available metagenome-assembled genomes (MAGs, completeness ≥80%) from 203 surveys worldwide as a culture-independent sample of bacterial and archaeal diversity, and compare these MAGs to the popular RefSeq genome database, which heavily relies on cultures. We compare the distribution of 12,454 KEGG gene orthologs (used as trait proxies) in the MAGs and RefSeq genomes, while controlling for environment type (ocean, soil, lake, bioreactor, human, and other animals). Using statistical modeling, we then determine the conditional probabilities that a species is represented in RefSeq depending on its genetic repertoire. We find that the majority of examined genes are significantly biased for or against in RefSeq. Our systematic estimates of gene prevalences across bacteria and archaea in nature and gene-specific biases in reference genomes constitutes a resource for addressing these issues in the future.
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Affiliation(s)
- Sage Albright
- Department of Biology, University of Oregon, Eugene, USA
| | - Stilianos Louca
- Department of Biology, University of Oregon, Eugene, USA.
- Institute of Ecology and Evolution, University of Oregon, Eugene, USA.
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15
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Cryptic Diversity of Black Band Disease Cyanobacteria in Siderastrea siderea Corals Revealed by Chemical Ecology and Comparative Genome-Resolved Metagenomics. Mar Drugs 2023; 21:md21020076. [PMID: 36827117 PMCID: PMC9967302 DOI: 10.3390/md21020076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/13/2023] [Accepted: 01/19/2023] [Indexed: 01/24/2023] Open
Abstract
Black band disease is a globally distributed and easily recognizable coral disease. Despite years of study, the etiology of this coral disease, which impacts dozens of stony coral species, is not completely understood. Although black band disease mats are predominantly composed of the cyanobacterial species Roseofilum reptotaenium, other filamentous cyanobacterial strains and bacterial heterotrophs are readily detected. Through chemical ecology and metagenomic sequencing, we uncovered cryptic strains of Roseofilum species from Siderastrea siderea corals that differ from those on other corals in the Caribbean and Pacific. Isolation of metabolites from Siderastrea-derived Roseofilum revealed the prevalence of unique forms of looekeyolides, distinct from previously characterized Roseofilum reptotaenium strains. In addition, comparative genomics of Roseofilum strains showed that only Siderastrea-based Roseofilum strains have the genetic capacity to produce lasso peptides, a family of compounds with diverse biological activity. All nine Roseofilum strains examined here shared the genetic capacity to produce looekeyolides and malyngamides, suggesting these compounds support the ecology of this genus. Similar biosynthetic gene clusters are not found in other cyanobacterial genera associated with black band disease, which may suggest that looekeyolides and malyngamides contribute to disease etiology through yet unknown mechanisms.
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16
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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: 9] [Impact Index Per Article: 9.0] [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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17
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Dirks AC, Mohamed OG, Schultz PJ, Miller AN, Tripathi A, James TY. Not all bad: Gyromitrin has a limited distribution in the false morels as determined by a new ultra high-performance liquid chromatography method. Mycologia 2023; 115:1-15. [PMID: 36541902 DOI: 10.1080/00275514.2022.2146473] [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: 12/24/2022]
Abstract
Gyromitrin (acetaldehyde N-methyl-N-formylhydrazone) and its homologs are deadly mycotoxins produced most infamously by the lorchel (also known as false morel) Gyromitra esculenta, which is paradoxically consumed as a delicacy in some parts of the world. There is much speculation about the presence of gyromitrin in other species of the lorchel family (Discinaceae), but no studies have broadly assessed its distribution. Given the history of poisonings associated with the consumption of G. esculenta and G. ambigua, we hypothesized that gyromitrin evolved in the last common ancestor of these taxa and would be present in their descendants with adaptive loss of function in the nested truffle clade, Hydnotrya. To test this hypothesis, we developed a sensitive analytical derivatization method for the detection of gyromitrin using 2,4-dinitrobenzaldehyde as the derivatization reagent. In total, we analyzed 66 specimens for the presence of gyromitrin over 105 tests. Moreover, we sequenced the nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS barcode) and nuc 28S rDNA to assist in species identification and to infer a supporting phylogenetic tree. We detected gyromitrin in all tested specimens from the G. esculenta group as well as G. leucoxantha. This distribution is consistent with a model of rapid evolution coupled with horizontal transfer, which is typical for secondary metabolites. We clarified that gyromitrin production in Discinaceae is both discontinuous and more limited than previously thought. Further research is required to elucidate the gyromitrin biosynthesis gene cluster and its evolutionary history in lorchels.
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Affiliation(s)
- Alden C Dirks
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48103
| | - Osama G Mohamed
- Natural Products Discovery Core, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48103.,Department of Pharmacognosy, Faculty of Pharmacy, Cairo University, Cairo 11562, Egypt
| | - Pamela J Schultz
- Natural Products Discovery Core, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48103
| | - Andrew N Miller
- Illinois Natural History Survey, University of Illinois Urbana-Champaign, Champaign, Illinois 61820
| | - Ashootosh Tripathi
- Natural Products Discovery Core, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48103.,Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48103
| | - Timothy Y James
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48103
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