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Shishido TK, Delbaje E, Wahlsten M, Vuori I, Jokela J, Gugger M, Fiore MF, Fewer DP. A cylindrospermopin-producing cyanobacterium isolated from a microbial mat in the Baltic Sea. Toxicon 2023:107205. [PMID: 37406865 DOI: 10.1016/j.toxicon.2023.107205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 06/12/2023] [Accepted: 06/21/2023] [Indexed: 07/07/2023]
Abstract
Toxic benthic mats of cyanobacteria are associated with water quality problems and animal poisonings around the world. A strain of the filamentous cyanobacterial genus Kamptonema was isolated from a water bloom in the Baltic Sea four decades ago and later shown to produce cylindrospermopsins. However, the exact habitat of this strain remains unclear and cylindrospermopsins have not yet been reported from water blooms in the Baltic Sea. Here, we report the isolation of Kamptonema sp. UHCC 0994 from a benthic microbial mat collected in shallow water on the coast of Helsinki. We obtained draft genome sequences for the Kamptonema spp. PCC 7926 and UHCC 0994 strains that were isolated from the Baltic Sea. These genomes were 90-96% similar to previously studied Kamptonema sp. PCC 6506 and Kamptonema formosum PCC 6407, which were isolated from benthic and North American freshwater environments, respectively. The genomes of all four Kamptonema strains encode complete cylindrospermopsin biosynthetic gene clusters. We detected the production of cylindrospermopsin and 7-epi-cylindrospermopsin in the four Kamptonema strains using high-resolution liquid chromatography mass spectrometry. The four strains encode genes for producing gas vesicles distributed in two to three different regions of their genomes. Kamptonema spp. UHCC 0994 and PCC 7926 have both retained the ability to regulate their buoyancy when grown in liquid culture. Together this suggests that these toxic cyanobacteria may exhibit a tychoplanktic lifestyle in the Baltic Sea. This study suggests that microbial mats containing cyanobacteria could be a source of environmental toxins in the Baltic Sea.
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Affiliation(s)
- Tania Keiko Shishido
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Viikinkaari 9, FI-00014, Helsinki, Finland
| | - Endrews Delbaje
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Viikinkaari 9, FI-00014, Helsinki, Finland; Center for Nuclear Energy in Agriculture, University of São Paulo, Avenida Centenário 303, Piracicaba, 13400-970, São Paulo, Brazil
| | - Matti Wahlsten
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Viikinkaari 9, FI-00014, Helsinki, Finland
| | - Inkeri Vuori
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Viikinkaari 9, FI-00014, Helsinki, Finland
| | - Jouni Jokela
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Viikinkaari 9, FI-00014, Helsinki, Finland
| | - Muriel Gugger
- Institut Pasteur, Université Paris Cité, Collection of Cyanobacteria, Paris, F-75015, France
| | - Marli F Fiore
- Center for Nuclear Energy in Agriculture, University of São Paulo, Avenida Centenário 303, Piracicaba, 13400-970, São Paulo, Brazil
| | - David P Fewer
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Viikinkaari 9, FI-00014, Helsinki, Finland.
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Zheng L, Liu Y, Li R, Yang Y, Jiang Y. Recent Advances in the Ecology of Bloom-Forming Raphidiopsis ( Cylindrospermopsis) raciborskii: Expansion in China, Intraspecific Heterogeneity and Critical Factors for Invasion. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:1984. [PMID: 36767351 PMCID: PMC9915880 DOI: 10.3390/ijerph20031984] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 01/09/2023] [Accepted: 01/18/2023] [Indexed: 06/18/2023]
Abstract
Water blooms caused by the invasive cyanobacterium Raphidiopsis raciborskii occur in many reservoirs in the tropical and subtropical regions of China. In recent decades, this species has spread rapidly to temperate regions. Phenotypic plasticity and climate warming are thought to promote the worldwide dispersion of R. raciborskii. However, investigations into the genetic and phenotypic diversities of this species have revealed significant intraspecific heterogeneity. In particular, competition between R. raciborskii and Microcystis aeruginosa was highly strain dependent. Although the concept of an ecotype was proposed to explain the heterogeneity of R. raciborskii strains with different geographic origins, microevolution is more reasonable for understanding the coexistence of different phenotypes and genotypes in the same environment. It has been suggested that intraspecific heterogeneity derived from microevolution is a strong driving force for the expansion of R. raciborskii. Additionally, temperature, nutrient fluctuations, and grazer disturbance are critical environmental factors that affect the population establishment of R. raciborskii in new environments. The present review provides new insights into the ecological mechanisms underlying the invasion of R. raciborskii in Chinese freshwater ecosystems.
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Affiliation(s)
- Ling Zheng
- Department of Biological Sciences and Technology, School of Environmental Studies, China University of Geosciences, Wuhan 430074, China
| | - Yang Liu
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Renhui Li
- College of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, China
| | - Yiming Yang
- Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou 510182, China
| | - Yongguang Jiang
- Department of Biological Sciences and Technology, School of Environmental Studies, China University of Geosciences, Wuhan 430074, China
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Méjean A, Lequin O, Ploux O. Identification of 7-Deoxy-desulfo-argino-cylindrospermopsin, the Missing Piece in Cylindrospermopsin Biosynthesis. J Am Chem Soc 2022; 144:14627-14637. [PMID: 35916199 DOI: 10.1021/jacs.2c03932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cylindrospermopsin, a major cyanotoxin, is produced by freshwater cyanobacteria. Its biosynthesis starts from arginine and glycine and involves five polyketide synthases and several tailoring enzymes. We report the identification of 7-deoxy-desulfo-argino-cylindrospermopsin in several cylindrospermopsin-producing cyanobacteria using mass spectrometry experiments. We have purified this new metabolite and established its structure by 1D and 2D NMR spectroscopy using scalar-based 1H-1H, 1H-13C, and 1H-15N as well as 2D 1H-1H ROESY correlation experiments. Using labeled arginines in isotopic incorporation experiments, we have shown that arginine is fully incorporated into 7-deoxy-desulfo-argino-cylindrospermopsin and that the uracil ring of cylindrospermopsin originates from the guanidino moiety of arginine, thus solving a long-standing puzzling question. CyrG and CyrH from the cylindrospermopsin-producing Oscillatoria sp. PCC 6506 were overproduced in Escherichia coli and purified to homogeneity. We showed that CyrG is a zinc-dependent hydrolase, homologous to adenosine deaminases, that transforms 7-deoxy-desulfo-argino-cylindrospermopsin into 7-deoxy-desulfo-cylindrospermopsin and ornithine, with the following kinetic parameters: KM = 0.21 ± 0.05 μM and kcat = 0.19 ± 0.02 min-1. CyrG contained 0.55 mol of zinc per mol of monomer but could be activated by FeII or CoII. CyrH contained almost no metal and showed no such activity even in the presence of excess metal. Using structure-based alignments and secondary structure predictions, we propose that the fifth and last polyketide synthase CyrF in cylindrospermopsin biosynthesis contains an unprecedented C-terminal domain homologous to N-acetyltransferases. We suggest that this domain catalyzes the condensation of the CyrF product with arginine to give 7-deoxy-desulfo-argino-cylindrospermopsin. This would be an unprecedented termination step for a polyketide synthase.
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Affiliation(s)
- Annick Méjean
- LIED, UMR 8236 CNRS, Université Paris Cité, 75205 Paris Cedex 13, France
| | - Olivier Lequin
- Sorbonne Université, École Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules, LBM, 75005 Paris, France
| | - Olivier Ploux
- LIED, UMR 8236 CNRS, Université Paris Cité, 75205 Paris Cedex 13, France.,Chimie ParisTech, PSL, 75005 Paris, France
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Dreher TW, Foss AJ, Davis EW, Mueller RS. 7-epi-cylindrospermopsin and microcystin producers among diverse Anabaena/Dolichospermum/Aphanizomenon CyanoHABs in Oregon, USA. HARMFUL ALGAE 2022; 116:102241. [PMID: 35710201 DOI: 10.1016/j.hal.2022.102241] [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: 01/11/2022] [Revised: 03/18/2022] [Accepted: 04/27/2022] [Indexed: 06/15/2023]
Abstract
Several genomes of Nostocales ADA clade members from the US Pacific Northwest were recently sequenced. Biosynthetic genes for microcystin, cylindrospermopsin or anatoxin-a were present in 7 of the 15 Dolichospermum/Anabaena strains and none of the 5 Aphanizomenon flos-aquae (AFA) strains. Toxin analyses (ELISA and LC-MS/MS) were conducted to quantitate and identify microcystin (MC) and cylindrospermopsin (CYN) congeners/analogs in samples dominated by Dolichospermum spp. of known genome sequence. MC-LR was the main congener produced by Dolichospermum spp. from Junipers Reservoir, Lake Billy Chinook and Odell Lake, while a congener provisionally identified as [Dha7]MC-HtyR was produced by a Dolichospermum sp. in Detroit Reservoir. A second Dolichospermum sp. from Detroit Reservoir was found to produce 7-epi-CYN, with 7-deoxy-CYN also present, but no CYN. The monitoring history of each of these lakes indicates the capacity for high levels of cyanotoxins during periods when Dolichospermum spp. are the dominant cyanobacteria. The diversity of ADA strains found in the US Pacific NW emphasizes the importance of these cyanobacteria as potentially toxic HAB formers in this temperate climatic region. Our results linking congener and genetic identity add data points that will help guide development of improved tools for predicting congener specificity from cyanotoxin gene sequences.
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Affiliation(s)
- Theo W Dreher
- Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA.
| | - Amanda J Foss
- GreenWater Laboratories, 205 Zeagler Drive, Suite 302, Palatka, FL 32177, USA.
| | - Edward W Davis
- Center for Quantitative Life Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Ryan S Mueller
- Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA
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