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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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2
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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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Kurtz T, Zeng T, Rosario-Ortiz FL. Photodegradation of cyanotoxins in surface waters. WATER RESEARCH 2021; 192:116804. [PMID: 33494040 DOI: 10.1016/j.watres.2021.116804] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/15/2020] [Accepted: 12/31/2020] [Indexed: 06/12/2023]
Abstract
Cyanotoxin-producing harmful algal blooms (HABs) are a global occurrence and pose ecotoxicological threats to humans and animals alike. The presence of cyanotoxins can seriously harm or kill nearby wildlife and restrict a body of water's use as a drinking water supply and recreational site, making it imperative to fully understand their fate and transport in natural waters. Photodegradation contributes to the overall degradation of cyanotoxins in environmental systems, especially for those present in the photic zone of surface waters. This makes photochemical transformation mechanisms important factors to account for when assessing the persistence of cyanotoxins in environmental systems. This paper reviews current knowledge on the photodegradation rates and pathways of cyanotoxins that can occur over the course of HABs. Sensitized, or indirect, photolysis contributes to the degradation of all cyanotoxins addressed in this paper (anatoxins, cylindrospermopsins, domoic acids, microcystins, and nodularins), with hydroxyl radicals (•OH), excited triplet states formed from the absorption of light by dissolved organic matter (3DOM*), and photosynthetic pigment sensitized pathways being of primary interest. Direct photolysis pathways play a less significant role, but are still relevant for most of the cyanotoxins discussed in this paper.
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Affiliation(s)
- Tyler Kurtz
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Colorado 80309, United States; Environmental Engineering Program, University of Colorado Boulder, Colorado 80309, United States
| | - Teng Zeng
- Department of Civil and Environmental Engineering, 151 Link Hall, Syracuse University, Syracuse, NY 13244, United States
| | - Fernando L Rosario-Ortiz
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Colorado 80309, United States; Environmental Engineering Program, University of Colorado Boulder, Colorado 80309, United States.
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Moraes ACN, Freire DS, Habibi H, Lowe J, Magalhães VF. Cylindrospermopsin impairs tubular transport function in kidney cells LLC-PK1. Toxicol Lett 2021; 344:26-33. [PMID: 33689780 DOI: 10.1016/j.toxlet.2021.03.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 03/01/2021] [Accepted: 03/04/2021] [Indexed: 01/03/2023]
Abstract
Cylindrospermopsin (CYN) has been involved in cases of poisoning in humans following ingestion. Studies have demonstrated that the kidney is the most affected organ. CYN exposure leads to low-molecular-weight proteinuria and increased excretions of the tubular enzymes in mice, suggesting the damage caused by CYN is mainly tubular. However, the mechanism involved in CYN nephrotoxicity remains unknown. Thus, in order to evaluate the effects of CYN exposure (0.1, 0.5 and 1.0 μg/mL) on tubular renal cells LLC-PK1 distinct mechanisms were analyzed by assessing cell death using flow cytometry, albumin uptake by fluorescence analysis, Na+/K+-ATPase activity by a colorimetric method, RT-qPCR of genes related to tubular transport and function as well as internalization of CYN by ELISA. In this study, CYN was found to induce necrosis in all concentrations. CYN also decreased albumin uptake as well as downregulated megalin and dab2 expression, both proteins involved in albumin endocytosis process. Moreover, CYN appears to be internalized by renal tubular cells through a receptor-mediated endocytosis. Finally, the present study demonstrates that CYN is responsible for disrupting tubular cell transport and function in LLC-PK1 cells.
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Affiliation(s)
- A C N Moraes
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - D S Freire
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - H Habibi
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - J Lowe
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - V F Magalhães
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.
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6
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Méjean A, Ploux O. Biosynthesis of Cylindrospermopsin in Cyanobacteria: Characterization of CyrJ the Sulfotransferase. JOURNAL OF NATURAL PRODUCTS 2021; 84:408-416. [PMID: 33439646 DOI: 10.1021/acs.jnatprod.0c01089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
7-Deoxy-desulfo-cylindrospermopsin was purified at small-scale from the supernatant of a culture of the cyanobacterium Oscillatoria sp. PCC 10702. This metabolite was obtained in a pure form using a three-step chromatographic procedure, and its identity was confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). LC-MS quantification showed that this metabolite was excreted in the culture medium of Oscillatoria sp. PCC 10702. Isotopic incorporation studies using [2-13C,15N]glycine, a cylindrospermopsin precursor, and Oscillatoria sp. PCC 10702 cells showed that glycine was incorporated into 7-deoxy-desulfo-cylindrospermopsin, 7-deoxy-cylindrospermopsin, 7-epi-cylindrospermopsin, and cylindrospermopsin. The isotopic incorporation rate was consistent with the following metabolic flux: 7-deoxy-desulfo-cylindrospermopsin → 7-deoxy-cylindrospermopsin → 7-epi-cylindrospermopsin and cylindrospermopsin. We have cloned the cyrJ gene into an expression vector and overproduced the putative sulfotransferase CyrJ in Escherichia coli. The purified protein CyrJ catalyzed, in vitro, the transfer of a sulfonate group from 3'-phosphoadenosine-5'-phosphosulfate (PAPS) to 7-deoxy-desulfo-cylindrospermopsin to give 7-deoxy-cylindrospermopsin. Kinetic analysis afforded the following apparent constants: KM app. (PAPS) = 0.12 μM, Vmax app. = 20 nM/min, KM app. (7-deoxy-desulfo-cylindrospermopsin) = 0.12 μM, and KI app. (7-deoxy-desulfo-cylindrospermopsin) = 4.1 μM. Preliminary data suggested that CyrJ catalyzed the reaction through a ternary-complex kinetic mechanism. All these data confirmed that CyrJ catalyzed a sulfotransfer during the penultimate step of the biosynthesis of cylindrospermopsin.
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Affiliation(s)
- Annick Méjean
- LIED, UMR 8236 CNRS, Université de Paris, 75205 Paris, Cedex 13, France
| | - Olivier Ploux
- LIED, UMR 8236 CNRS, Université de Paris, 75205 Paris, Cedex 13, France
- Chimie ParisTech, PSL, 75005 Paris, France
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7
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Zwick CR, Renata H. Harnessing the biocatalytic potential of iron- and α-ketoglutarate-dependent dioxygenases in natural product total synthesis. Nat Prod Rep 2020; 37:1065-1079. [PMID: 32055818 PMCID: PMC7426249 DOI: 10.1039/c9np00075e] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Covering: up to the end of 2019Iron- and α-ketoglutarate-dependent dioxygenases (Fe/αKGs) represent a versatile and intriguing enzyme family by virtue of their ability to directly functionalize unactivated C-H bonds at the cost of αKG and O2. Fe/αKGs play an important role in the biosynthesis of natural products, valuable biologically active secondary metabolites frequently pursued as drug leads. The field of natural product total synthesis seeks to contruct these molecules as effeciently as possible, although natural products continue to challenge chemists due to their intricate structural complexity. Chemoenzymatic approaches seek to remedy the shortcomings of traditional synthetic methodology by combining Nature's biosynthetic machinery with traditional chemical methods to efficiently construct natural products. Although other oxygenase families have been widely employed for this purpose, Fe/αKGs remain underutilized. The following review will cover recent chemoenzymatic total syntheses involving Fe/αKG enzymes. Additionally, related information involving natural product biosynthesis, methods development, and non-chemoenzymatic total syntheses will be discussed to inform retrosynthetic logic and synthetic design.
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Affiliation(s)
- Christian R Zwick
- The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA.
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8
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Cullen A, Pearson LA, Mazmouz R, Liu T, Soeriyadi AH, Ongley SE, Neilan BA. Heterologous expression and biochemical characterisation of cyanotoxin biosynthesis pathways. Nat Prod Rep 2019; 36:1117-1136. [DOI: 10.1039/c8np00063h] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review discusses cyanotoxin biosynthetic pathways and highlights the heterologous expression and biochemical studies used to characterise them.
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Affiliation(s)
- Alescia Cullen
- School of Environmental and Life Sciences
- University of Newcastle
- Callaghan 2308
- Australia
| | - Leanne A. Pearson
- School of Environmental and Life Sciences
- University of Newcastle
- Callaghan 2308
- Australia
| | - Rabia Mazmouz
- School of Environmental and Life Sciences
- University of Newcastle
- Callaghan 2308
- Australia
| | - Tianzhe Liu
- School of Biotechnology and Biomolecular Sciences
- The University of New South Wales
- Sydney 2052
- Australia
| | - Angela H. Soeriyadi
- School of Biotechnology and Biomolecular Sciences
- The University of New South Wales
- Sydney 2052
- Australia
| | - Sarah E. Ongley
- School of Environmental and Life Sciences
- University of Newcastle
- Callaghan 2308
- Australia
| | - Brett A. Neilan
- School of Environmental and Life Sciences
- University of Newcastle
- Callaghan 2308
- Australia
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9
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Characterization of CyrI, the hydroxylase involved in the last step of cylindrospermopsin biosynthesis: Binding studies, site-directed mutagenesis and stereoselectivity. Arch Biochem Biophys 2018; 647:1-9. [DOI: 10.1016/j.abb.2018.04.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 04/06/2018] [Accepted: 04/09/2018] [Indexed: 11/21/2022]
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10
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Mailyan AK, Chen JL, Li W, Keller AA, Sternisha SM, Miller BG, Zakarian A. Short Total Synthesis of [ 15N 5]-Cylindrospermopsins from 15NH 4Cl Enables Precise Quantification of Freshwater Cyanobacterial Contamination. J Am Chem Soc 2018; 140:6027-6032. [PMID: 29672038 PMCID: PMC6312099 DOI: 10.1021/jacs.8b03071] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fresh water cyanobacterial algal blooms represent a major health risk because these organisms produce cylindrospermopsin, a toxic, structurally complex, zwitterionic uracil-guanidine alkaloid recognized by the EPA as a dangerous drinking water contaminant. At present, the ability to detect and quantify the presence of cylindrospermospin in water samples is severely hampered by the lack of an isotopically labeled standard for analytical mass spectrometry. Herein, we present a concise, scaled total synthesis of 15N cylindrospermosin from 15N ammonium chloride, which leverages a unique stereoselective intramolecular double conjugate addition step to assemble the tricyclic guanidine core. In addition to providing the first pure isotopically labeled probe for precise quantification of this potent biotoxin in fresh water sources, our results demonstrate how unique constraints associated with isotope incorporation compel novel solutions to synthesis design.
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Affiliation(s)
- Artur K Mailyan
- Department of Chemistry and Biochemistry , University of California , Santa Barbara , California 93110 , United States
| | - Joanna L Chen
- Department of Chemistry and Biochemistry , University of California , Santa Barbara , California 93110 , United States
| | - Weiwei Li
- Bren School of Environmental Science and Management , University of California , Santa Barbara , California 93106 , United States
| | - Arturo A Keller
- Bren School of Environmental Science and Management , University of California , Santa Barbara , California 93106 , United States
| | - Shawn M Sternisha
- Department of Chemistry and Biochemistry , Florida State University , Tallahassee , Florida 32310 , United States
| | - Brian G Miller
- Department of Chemistry and Biochemistry , Florida State University , Tallahassee , Florida 32310 , United States
| | - Armen Zakarian
- Department of Chemistry and Biochemistry , University of California , Santa Barbara , California 93110 , United States
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11
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Moraes A, Magalhães V. Renal tubular damage caused by cylindrospermopsin (cyanotoxin) in mice. Toxicol Lett 2018; 286:89-95. [DOI: 10.1016/j.toxlet.2017.12.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 11/24/2017] [Accepted: 12/31/2017] [Indexed: 11/25/2022]
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12
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Otten TG, Paerl HW. Health Effects of Toxic Cyanobacteria in U.S. Drinking and Recreational Waters: Our Current Understanding and Proposed Direction. Curr Environ Health Rep 2016; 2:75-84. [PMID: 26231244 DOI: 10.1007/s40572-014-0041-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Cyanobacterial-derived water quality impairment issues are a growing concern worldwide. In addition to their ecological impacts, these organisms are prolific producers of bioactive secondary metabolites, many of which are known human intoxicants. To date only a handful of these compounds have been thoroughly studied and their toxicological risks estimated. While there are currently no national guidelines in place to deal with this issue, it is increasingly likely that within the next several years guidelines will be implemented. The intent of this review is to survey all relevant literature pertaining to cyanobacterial harmful algal bloom secondary metabolites, to inform a discussion on how best to manage this global public health threat.
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Affiliation(s)
- Timothy G Otten
- Department of Microbiology, Oregon State University, 226 Nash Hall, Corvallis, OR, 97331, USA,
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13
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Preußel K, Chorus I, Fastner J. Nitrogen limitation promotes accumulation and suppresses release of cylindrospermopsins in cells of Aphanizomenon sp. Toxins (Basel) 2014; 6:2932-47. [PMID: 25271784 PMCID: PMC4210877 DOI: 10.3390/toxins6102932] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 08/29/2014] [Accepted: 09/12/2014] [Indexed: 12/05/2022] Open
Abstract
As the biosynthesis of cylindrospermopsin (CYN) is assumed to depend on nitrogen availability, this study investigated the impact of nitrogen availability on intra- and extracellular CYN and deoxy-CYN (D-CYN) contents in three Aphanizomenon strains from temperate waters. Nitrogen deficient (−N) cultures showed a prolonged growth phase and intracellular toxin accumulation by a factor of 2–6. In contrast, cultures with additional nitrate supply (+N) did not accumulate CYN within the cells. Instead, the maximum conceivable CYN release estimated for dead cells (identified by SYTOX® Green staining) was much lower than the concentrations of dissolved CYN actually observed, suggesting these cultures actively release CYN from intact cells. Furthermore, we found remarkably altered proportions of CYN to D-CYN: as batch cultures grew, the proportion of D-CYN increased by up to 40% in +N medium, whereas D-CYN remained constant or decreased slightly in −N medium. Since +N cultures showed similar toxin patterns as −P cultures with increased extracellular CYNs and higher proportion of D-CYN we conclude that nitrogen limitation may affect the way the cells economize resources, especially the yield from phosphorus pools, and that this has an impact on CYN production and release. For water management, these result imply that nutrient availability not only determines the abundance of potentially CYN-producing cyanobacteria, but also the amount of extracellular CYNs (challenging drinking-water treatment) as well as the ratio of D-CYN to CYN (affecting toxicity).
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Affiliation(s)
- Karina Preußel
- Federal Environment Agency, Schichauweg 58, 12307 Berlin, Germany.
| | - Ingrid Chorus
- Federal Environment Agency, Schichauweg 58, 12307 Berlin, Germany.
| | - Jutta Fastner
- Federal Environment Agency, Schichauweg 58, 12307 Berlin, Germany.
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Jiang Y, Xiao P, Yu G, Shao J, Liu D, Azevedo SMFO, Li R. Sporadic distribution and distinctive variations of cylindrospermopsin genes in cyanobacterial strains and environmental samples from Chinese freshwater bodies. Appl Environ Microbiol 2014; 80:5219-30. [PMID: 24928879 PMCID: PMC4136083 DOI: 10.1128/aem.00551-14] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Accepted: 06/05/2014] [Indexed: 11/20/2022] Open
Abstract
Increasing reports of cylindrospermopsins (CYNs) in freshwater ecosystems have promoted the demand for identifying all of the potential CYN-producing cyanobacterial species. The present study explored the phylogenetic distribution and evolution of cyr genes in cyanobacterial strains and water samples from China. Four Cylindrospermopsis strains and two Raphidiopsis strains were confirmed to produce CYNs. Mutant cyrI and cyrK genes were observed in these strains. Cloned cyr gene sequences from eight water bodies were clustered with cyr genes from Cylindrospermopsis and Raphidiopsis (C/R group) in the phylogenetic trees with high similarities (99%). Four cyrI sequence types and three cyrJ sequence types were observed to have different sequence insertions and repeats. Phylogenetic analysis of the rpoC1 sequences of the C/R group revealed four conserved clades, namely, clade I, clade II, clade III, and clade V. High sequence similarities (>97%) in each clade and a divergent clade IV were observed. Therefore, CYN producers were sporadically distributed in congeneric and paraphyletic C/R group species in Chinese freshwater ecosystems. In the evolution of cyr genes, intragenomic translocations and intergenomic transfer between local Cylindrospermopsis and Raphidiopsis were emphasized and probably mediated by transposases. This research confirms the existence of CYN-producing Cylindrospermopsis in China and reveals the distinctive variations of cyr genes.
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Affiliation(s)
- Yongguang Jiang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, People's Republic of China University of Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Peng Xiao
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, People's Republic of China University of Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Gongliang Yu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, People's Republic of China
| | - Jihai Shao
- Resources and Environment College, Hunan Agricultural University, Changsha, People's Republic of China
| | - Deming Liu
- Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Agricultural University, Changsha, People's Republic of China
| | - Sandra M F O Azevedo
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Cidade Universitária, Rio de Janeiro, Brazil
| | - Renhui Li
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, People's Republic of China
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15
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Stucken K, John U, Cembella A, Soto-Liebe K, Vásquez M. Impact of nitrogen sources on gene expression and toxin production in the diazotroph Cylindrospermopsis raciborskii CS-505 and non-diazotroph Raphidiopsis brookii D9. Toxins (Basel) 2014; 6:1896-915. [PMID: 24956074 PMCID: PMC4073136 DOI: 10.3390/toxins6061896] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 05/31/2014] [Accepted: 06/09/2014] [Indexed: 11/16/2022] Open
Abstract
Different environmental nitrogen sources play selective roles in the development of cyanobacterial blooms and noxious effects are often exacerbated when toxic cyanobacteria are dominant. Cylindrospermopsis raciborskii CS-505 (heterocystous, nitrogen fixing) and Raphidiopsis brookii D9 (non-N2 fixing) produce the nitrogenous toxins cylindrospermopsin (CYN) and paralytic shellfish toxins (PSTs), respectively. These toxin groups are biosynthesized constitutively by two independent putative gene clusters, whose flanking genes are target for nitrogen (N) regulation. It is not yet known how or if toxin biosynthetic genes are regulated, particularly by N-source dependency. Here we show that binding boxes for NtcA, the master regulator of N metabolism, are located within both gene clusters as potential regulators of toxin biosynthesis. Quantification of intra- and extracellular toxin content in cultures at early stages of growth under nitrate, ammonium, urea and N-free media showed that N-sources influence neither CYN nor PST production. However, CYN and PST profiles were altered under N-free medium resulting in a decrease in the predicted precursor toxins (doCYN and STX, respectively). Reduced STX amounts were also observed under growth in ammonium. Quantification of toxin biosynthesis and transport gene transcripts revealed a constitutive transcription under all tested N-sources. Our data support the hypothesis that PSTs and CYN are constitutive metabolites whose biosynthesis is correlated to cyanobacterial growth rather than directly to specific environmental conditions. Overall, the constant biosynthesis of toxins and expression of the putative toxin-biosynthesis genes supports the usage of qPCR probes in water quality monitoring of toxic cyanobacteria.
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Affiliation(s)
- Karina Stucken
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany.
| | - Uwe John
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany.
| | - Allan Cembella
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany.
| | - Katia Soto-Liebe
- Department of Molecular Genetics and Microbiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile.
| | - Mónica Vásquez
- Department of Molecular Genetics and Microbiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile.
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Davis TW, Orr PT, Boyer GL, Burford MA. Investigating the production and release of cylindrospermopsin and deoxy-cylindrospermopsin by Cylindrospermopsis raciborskii over a natural growth cycle. HARMFUL ALGAE 2014; 31:18-25. [PMID: 28040107 DOI: 10.1016/j.hal.2013.09.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 09/16/2013] [Accepted: 09/17/2013] [Indexed: 05/06/2023]
Abstract
Many harmful cyanobacterial genera have strains that can produce potent toxins and other biologically active compounds that present a risk to the health of humans and other animals that consume or contact contaminated water. Cylindrospermopsins (CYNs) are produced by several species of cyanobacteria including Cylindrospermopsis raciborskii (Woloszynska) Seenayya and Subba Raju. Previous studies have used filtration methods to separate between the particulate and dissolved CYNs pools. Filtration may lyse cells and thus overestimate the dissolved CYNs pool. Here we employed a novel passive sampling technique to measure the proportion of dissolved CYNs in two Australian strains of C. raciborskii over the growth cycle while minimizing potential overestimation of the dissolved CYNs pool. We simultaneously compared the ratios of the two major CYNs produced by Australian strains of C. raciborskii: cylindrospermopsin (CYN) and deoxy-CYN in the particulate and dissolved pools. CYNs stayed within the cells during log phase but accumulated in the water column during stationary and senescent phases. The proportion of deoxy-CYN to CYN differed between strains but increased in both as cells aged. We conclude that while active release or leaking of CYNs from actively growing cells does occur, CYNs in the water column were primarily a result of cell lysis during stationary phase or due to other environmental stressors. The production of CYN and deoxy-CYN were a constitutive process and both the concentration of, ratio between, and release of CYN and deoxy-CYN were strain dependent. Future studies must account for the genetic diversity of CYN producers when investigating the production of CYNs in natural systems.
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Affiliation(s)
- Timothy W Davis
- Australian Rivers Institute, Griffith University, 170 Kessels Road, Nathan, Qld 4111, Australia.
| | - Philip T Orr
- Australian Rivers Institute, Griffith University, 170 Kessels Road, Nathan, Qld 4111, Australia; Seqwater, PO Box 16146, City East, Qld 4002, Australia
| | - Gregory L Boyer
- Chemistry Department, State University of New York, College of Environmental Science and Forestry, 1 Forestry Drive, Syracuse, NY 13210, United States
| | - Michele A Burford
- Australian Rivers Institute, Griffith University, 170 Kessels Road, Nathan, Qld 4111, Australia
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17
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de la Cruz AA, Hiskia A, Kaloudis T, Chernoff N, Hill D, Antoniou MG, He X, Loftin K, O'Shea K, Zhao C, Pelaez M, Han C, Lynch TJ, Dionysiou DD. A review on cylindrospermopsin: the global occurrence, detection, toxicity and degradation of a potent cyanotoxin. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2013; 15:1979-2003. [PMID: 24056894 DOI: 10.1039/c3em00353a] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Cylindrospermopsin is an important cyanobacterial toxin found in water bodies worldwide. The ever-increasing and global occurrence of massive and prolonged blooms of cylindrospermopsin-producing cyanobacteria poses a potential threat to both human and ecosystem health. Its toxicity is associated with metabolic activation and may involve mechanisms that adversely affect a wide variety of targets in an organism. Cylindrospermopsin has been shown to be cytotoxic, dermatotoxic, genotoxic, hepatotoxic in vivo, developmentally toxic, and may be carcinogenic. Human exposure may occur through drinking water, during recreational activities and by consuming foods in which the toxin may have bioaccumulated. Drinking water shortages of sufficient quality coupled with growing human pressures and climate variability and change necessitate an integrated and sustainable water management program. This review presents an overview of the importance of cylindrospermopsin, its detection, toxicity, worldwide distribution, and lastly, its chemical and biological degradation and removal by natural processes and drinking water treatment processes.
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Affiliation(s)
- Armah A de la Cruz
- Office of Research and Development, US Environmental Protection Agency, Cincinnati, Ohio, USA
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18
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Dittmann E, Fewer DP, Neilan BA. Cyanobacterial toxins: biosynthetic routes and evolutionary roots. FEMS Microbiol Rev 2013; 37:23-43. [DOI: 10.1111/j.1574-6976.2012.12000.x] [Citation(s) in RCA: 239] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 08/22/2012] [Accepted: 08/24/2012] [Indexed: 11/27/2022] Open
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19
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Hibi M, Kawashima T, Kasahara T, Sokolov P, Smirnov S, Kodera T, Sugiyama M, Shimizu S, Yokozeki K, Ogawa J. A novel Fe(II)/α-ketoglutarate-dependent dioxygenase fromBurkholderia ambifariahas β-hydroxylating activity ofN-succinyl l-leucine. Lett Appl Microbiol 2012; 55:414-9. [DOI: 10.1111/j.1472-765x.2012.03308.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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20
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l-Leucine 5-hydroxylase of Nostoc punctiforme is a novel type of Fe(II)/α-ketoglutarate-dependent dioxygenase that is useful as a biocatalyst. Appl Microbiol Biotechnol 2012; 97:2467-72. [DOI: 10.1007/s00253-012-4136-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 04/22/2012] [Accepted: 04/23/2012] [Indexed: 10/28/2022]
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21
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Kaplan A, Harel M, Kaplan-Levy RN, Hadas O, Sukenik A, Dittmann E. The languages spoken in the water body (or the biological role of cyanobacterial toxins). Front Microbiol 2012; 3:138. [PMID: 22529842 PMCID: PMC3328848 DOI: 10.3389/fmicb.2012.00138] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Accepted: 03/23/2012] [Indexed: 11/13/2022] Open
Abstract
Although intensification of toxic cyanobacterial blooms over the last decade is a matter of growing concern due to bloom impact on water quality, the biological role of most of the toxins produced is not known. In this critical review we focus primarily on the biological role of two toxins, microcystins and cylindrospermopsin, in inter- and intra-species communication and in nutrient acquisition. We examine the experimental evidence supporting some of the dogmas in the field and raise several open questions to be dealt with in future research. We do not discuss the health and environmental implications of toxin presence in the water body.
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Affiliation(s)
- Aaron Kaplan
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem Jerusalem, Israel.
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22
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Jiang Y, Xiao P, Yu G, Sano T, Pan Q, Li R. Molecular basis and phylogenetic implications of deoxycylindrospermopsin biosynthesis in the cyanobacterium Raphidiopsis curvata. Appl Environ Microbiol 2012; 78:2256-63. [PMID: 22287011 PMCID: PMC3302619 DOI: 10.1128/aem.07321-11] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Accepted: 01/13/2012] [Indexed: 11/20/2022] Open
Abstract
New insights into the distribution and biochemistry of the cyanotoxin cylindrospermopsin (CYN) have been provided by the recent determination of its biosynthesis gene cluster (cyr) in several cyanobacterial species. Raphidiopsis curvata CHAB1150 isolated from China was analyzed for CYN analogues. Only 7-deoxy-CYN was detected in the cell extracts. The cyr gene cluster of R. curvata CHAB1150 was sequenced, and the cyr genes of this strain were found to have extremely high similarities (96% to 100%) to those from other nostocalean species. These species include Cylindrospermopsis raciborskii AWT205, Aphanizomenon sp. strain 10E6, and Aphanizomenon ovalisporum ILC-146. Insertion mutation was identified within the cyrI gene, and transcripts of cyrI and another functional gene cyrJ were detected in R. curvata CHAB1150. General congruence between the phylogenetic trees based on both cyr and 16S rrn was displayed. Neutral evolution was found on the whole sequences of the cyr genes, and 0 to 89 negative selected codons were detected in each gene. Therefore, the function of CyrI is to catalyze the oxygenation of 7-deoxy-CYN in CYN biosynthesis. The transcripts of the mutated cyrI gene may result from polycistronic transcription. The high conservation of the cyr genes may be ascribed to purifying selection and horizontal gene transfer.
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Affiliation(s)
- Yongguang Jiang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, People's Republic of China
- Graduate School of Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Peng Xiao
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, People's Republic of China
- Graduate School of Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Gongliang Yu
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, People's Republic of China
| | - Tomoharu Sano
- National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, Japan
| | - Qianqian Pan
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, People's Republic of China
- Graduate School of Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Renhui Li
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, People's Republic of China
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23
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Abstract
This review covers the literature on the chemically mediated ecology of cyanobacteria, including ultraviolet radiation protection, feeding-deterrence, allelopathy, resource competition, and signalling. To highlight the chemical and biological diversity of this group of organisms, evolutionary and chemotaxonomical studies are presented. Several technologically relevant aspects of cyanobacterial chemical ecology are also discussed.
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Affiliation(s)
- Pedro N Leão
- CIIMAR/CIMAR, Center for Marine and Environmental Research, University of Porto, Rua dos Bragas 289, 4050-123, Porto, Portugal.
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24
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Kehr JC, Gatte Picchi D, Dittmann E. Natural product biosyntheses in cyanobacteria: A treasure trove of unique enzymes. Beilstein J Org Chem 2011; 7:1622-35. [PMID: 22238540 PMCID: PMC3252866 DOI: 10.3762/bjoc.7.191] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 09/19/2011] [Indexed: 11/25/2022] Open
Abstract
Cyanobacteria are prolific producers of natural products. Investigations into the biochemistry responsible for the formation of these compounds have revealed fascinating mechanisms that are not, or only rarely, found in other microorganisms. In this article, we survey the biosynthetic pathways of cyanobacteria isolated from freshwater, marine and terrestrial habitats. We especially emphasize modular nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS) pathways and highlight the unique enzyme mechanisms that were elucidated or can be anticipated for the individual products. We further include ribosomal natural products and UV-absorbing pigments from cyanobacteria. Mechanistic insights obtained from the biochemical studies of cyanobacterial pathways can inspire the development of concepts for the design of bioactive compounds by synthetic-biology approaches in the future.
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Affiliation(s)
- Jan-Christoph Kehr
- University of Potsdam, Institute for Biochemistry and Biology, Karl-Liebknecht-Str. 24/25, 14476 Potsdam-Golm, Germany
| | - Douglas Gatte Picchi
- University of Potsdam, Institute for Biochemistry and Biology, Karl-Liebknecht-Str. 24/25, 14476 Potsdam-Golm, Germany
| | - Elke Dittmann
- University of Potsdam, Institute for Biochemistry and Biology, Karl-Liebknecht-Str. 24/25, 14476 Potsdam-Golm, Germany
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25
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Affiliation(s)
- Daniel M Evans
- School of Chemistry, Bangor University, Bangor, Gwynedd, UK
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