1
|
Soeriyadi AH, Mazmouz R, Pickford R, Al‐Sinawi B, Kellmann R, Pearson LA, Neilan BA. Cover Feature: Heterologous Expression of an Unusual Ketosynthase, SxtA, Leads to Production of Saxitoxin Intermediates in
Escherichia coli
(5/2021). Chembiochem 2021. [DOI: 10.1002/cbic.202100062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Angela H. Soeriyadi
- School of Biotechnology and Biomolecular Sciences University of New South Wales Kensington NSW 2052 Australia
| | - Rabia Mazmouz
- School of Biotechnology and Biomolecular Sciences University of New South Wales Kensington NSW 2052 Australia
| | - Russell Pickford
- Bioanalytical Mass Spectrometry Facility University of New South Wales Kensington NSW 2052 Australia
| | - Bakir Al‐Sinawi
- School of Biotechnology and Biomolecular Sciences University of New South Wales Kensington NSW 2052 Australia
| | - Ralf Kellmann
- Department of Biological Sciences University of Bergen Bergen 5020 Norway
| | - Leanne A. Pearson
- School of Environmental and Life Sciences University of Newcastle Callaghan NSW 2308 Australia
| | - Brett A. Neilan
- School of Environmental and Life Sciences University of Newcastle Callaghan NSW 2308 Australia
| |
Collapse
|
2
|
Soeriyadi AH, Mazmouz R, Pickford R, Al-Sinawi B, Kellmann R, Pearson LA, Neilan BA. Heterologous Expression of an Unusual Ketosynthase, SxtA, Leads to Production of Saxitoxin Intermediates in Escherichia coli. Chembiochem 2020; 22:845-849. [PMID: 33084210 DOI: 10.1002/cbic.202000675] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/19/2020] [Indexed: 11/06/2022]
Abstract
Paralytic shellfish toxins (PSTs) are neurotoxic alkaloids produced by freshwater cyanobacteria and marine dinoflagellates. Due to their antagonism of voltage-gated sodium channels in excitable cells, certain analogues are of significant pharmacological interest. The biosynthesis of the parent compound, saxitoxin, is initiated with the formation of 4-amino-3-oxo-guanidinoheptane (ethyl ketone) by an unusual polyketide synthase-like enzyme, SxtA. We have heterologously expressed SxtA from Raphidiopsis raciborskii T3 in Escherichia coli and analysed its activity in vivo. Ethyl ketone and a truncated analogue, methyl ketone, were detected by HPLC-ESI-HRMS analysis, thus suggesting that SxtA has relaxed substrate specificity in vivo. The chemical structures of these products were further verified by tandem mass spectrometry and labelled-precursor feeding with [guanidino-15 N2 ] arginine and [1,2-13 C2 ] acetate. These results indicate that the reactions catalysed by SxtA could give rise to multiple PST variants, including analogues of ecological and pharmacological significance.
Collapse
Affiliation(s)
- Angela H Soeriyadi
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, NSW 2052, Australia
| | - Rabia Mazmouz
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, NSW 2052, Australia
| | - Russell Pickford
- Bioanalytical Mass Spectrometry Facility, University of New South Wales, Kensington, NSW 2052, Australia
| | - Bakir Al-Sinawi
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, NSW 2052, Australia
| | - Ralf Kellmann
- Department of Biological Sciences, University of Bergen, Bergen, 5020, Norway
| | - Leanne A Pearson
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Brett A Neilan
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
| |
Collapse
|
3
|
D'Agostino PM, Al-Sinawi B, Mazmouz R, Muenchhoff J, Neilan BA, Moffitt MC. Identification of promoter elements in the Dolichospermum circinale AWQC131C saxitoxin gene cluster and the experimental analysis of their use for heterologous expression. BMC Microbiol 2020; 20:35. [PMID: 32070286 PMCID: PMC7027233 DOI: 10.1186/s12866-020-1720-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 02/03/2020] [Indexed: 01/06/2023] Open
Abstract
Background Dolichospermum circinale is a filamentous bloom-forming cyanobacterium responsible for biosynthesis of the paralytic shellfish toxins (PST), including saxitoxin. PSTs are neurotoxins and in their purified form are important analytical standards for monitoring the quality of water and seafood and biomedical research tools for studying neuronal sodium channels. More recently, PSTs have been recognised for their utility as local anaesthetics. Characterisation of the transcriptional elements within the saxitoxin (sxt) biosynthetic gene cluster (BGC) is a first step towards accessing these molecules for biotechnology. Results In D. circinale AWQC131C the sxt BGC is transcribed from two bidirectional promoter regions encoding five individual promoters. These promoters were identified experimentally using 5′ RACE and their activity assessed via coupling to a lux reporter system in E. coli and Synechocystis sp. PCC 6803. Transcription of the predicted drug/metabolite transporter (DMT) encoded by sxtPER was found to initiate from two promoters, PsxtPER1 and PsxtPER2. In E. coli, strong expression of lux from PsxtP, PsxtD and PsxtPER1 was observed while expression from Porf24 and PsxtPER2 was remarkably weaker. In contrast, heterologous expression in Synechocystis sp. PCC 6803 showed that expression of lux from PsxtP, PsxtPER1, and Porf24 promoters was statistically higher compared to the non-promoter control, while PsxtD showed poor activity under the described conditions. Conclusions Both of the heterologous hosts investigated in this study exhibited high expression levels from three of the five sxt promoters. These results indicate that the majority of the native sxt promoters appear active in different heterologous hosts, simplifying initial cloning efforts. Therefore, heterologous expression of the sxt BGC in either E. coli or Synechocystis could be a viable first option for producing PSTs for industrial or biomedical purposes.
Collapse
Affiliation(s)
- Paul M D'Agostino
- School of Science, Western Sydney University, Sydney, NSW, Australia.,School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.,Biosystems Chemistry, Department of Chemistry, Technische Universität München, Garching, Germany.,Technical Biochemistry, Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Bakir Al-Sinawi
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Rabia Mazmouz
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Julia Muenchhoff
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.,Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales, Sydney, Australia
| | - Brett A Neilan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia. .,School of Environmental and Life Sciences, University of Newcastle, Callaghan, Australia.
| | | |
Collapse
|
4
|
Liu T, Mazmouz R, Pearson LA, Neilan BA. Mutagenesis of the Microcystin Tailoring and Transport Proteins in a Heterologous Cyanotoxin Expression System. ACS Synth Biol 2019; 8:1187-1194. [PMID: 31042359 DOI: 10.1021/acssynbio.9b00068] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The microcystins are a large group of cyclic peptide hepatotoxins produced by several genera of freshwater cyanobacteria. The genes responsible for microcystin biosynthesis are encoded within a large (∼55 kbp) gene cluster, mcyA-J. The recent establishment of a cyanotoxin heterologous expression system in Escherichia coli has provided the means to study microcystin biosynthesis in a genetically tractable, rapidly growing host. Using this system, we demonstrate that deletion of the ABC-transporter, mcyH, and dehydrogenase, mcyI, abolishes microcystin production, while deletion of the O-methyltransferase, mcyJ, results in the production of the demethylated (DM) toxin [d-Asp3, DMAdda5]microcystin-LR. Both methylated and DM toxin variants were heterologously produced at high titers and efficiently exported into the extracellular medium, enabling easy purification. The results show that the mcy gene cluster can be engineered in E. coli to study the function of its individual components and direct the synthesis of particular microcystin variants. This technology could potentially be applied to other natural products of ecological and biomedical significance.
Collapse
Affiliation(s)
- Tianzhe Liu
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, NSW 2052, Sydney, Australia
| | - Rabia Mazmouz
- School of Environmental and Life Sciences, The University of Newcastle, NSW 2308, Callaghan, Australia
| | - Leanne A. Pearson
- School of Environmental and Life Sciences, The University of Newcastle, NSW 2308, Callaghan, Australia
| | - Brett A. Neilan
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, NSW 2052, Sydney, Australia
- School of Environmental and Life Sciences, The University of Newcastle, NSW 2308, Callaghan, Australia
| |
Collapse
|
5
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
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
| |
Collapse
|
6
|
Cullen A, D’Agostino PM, Mazmouz R, Pickford R, Wood S, Neilan BA. Insertions within the Saxitoxin Biosynthetic Gene Cluster Result in Differential Toxin Profiles. ACS Chem Biol 2018; 13:3107-3114. [PMID: 30296060 DOI: 10.1021/acschembio.8b00608] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The neurotoxin saxitoxin and related paralytic shellfish toxins are produced by multiple species of cyanobacteria and dinoflagellates. This study investigates the two saxitoxin-producing strains of Scytonema crispum, CAWBG524 and CAWBG72, isolated in New Zealand. Each strain was previously reported to have a distinct paralytic shellfish toxin profile, a rare observation between strains within the same species. Sequencing of the saxitoxin biosynthetic clusters ( sxt) from S. crispum CAWBG524 and S. crispum CAWBG72 revealed the largest sxt gene clusters described to date. The distinct toxin profiles of each strain were correlated to genetic differences in sxt tailoring enzymes, specifically the open-reading frame disruption of the N-21 sulfotransferase sxtN, adenylylsulfate kinase sxtO, and the C-11 dioxygenase sxtDIOX within S. crispum CAWBG524 via genetic insertions. Heterologous overexpression of SxtN allowed for the proposal of saxitoxin and 3'-phosphoadenosine 5'-phosphosulfate as substrate and cofactor, respectively, using florescence binding assays. Further, catalytic activity of SxtN was confirmed by the in vitro conversion of saxitoxin to the N-21 sulfonated analog gonyautoxin 5, making this the first known report to biochemically confirm the function of a sxt tailoring enzyme. Further, SxtN could not convert neosaxitoxin to its N-21 sulfonated analog gonyautoxin 6, indicating paralytic shellfish toxin biosynthesis most likely occurs along a predefined route. In this study, we identified key steps toward the biosynthetic conversation of saxitoxin to other paralytic shellfish toxins.
Collapse
Affiliation(s)
- Alescia Cullen
- School of Environmental and Life Sciences, University of Newcastle, Newcastle, NSW 2308, Australia
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Paul M. D’Agostino
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
- Biosystems Chemistry, Department of Chemistry and Center for Integrated Protein Science Munich (CIPSM), Technische Universität München, Garching 85747, Germany
| | - Rabia Mazmouz
- School of Environmental and Life Sciences, University of Newcastle, Newcastle, NSW 2308, Australia
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Russell Pickford
- Bioanalytical Mass Spectrometry Facility, Mark Wainwright Analytical Centre, University of New South Wales, Sydney, NSW 2052, Australia
| | - Susanna Wood
- Coastal and Freshwater Group, Cawthron Institute, Nelson 7001, New Zealand
| | - Brett A. Neilan
- School of Environmental and Life Sciences, University of Newcastle, Newcastle, NSW 2308, Australia
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| |
Collapse
|
7
|
Mazmouz R, Liu T, Neilan B, Mejean A, Ploux O. Cyanotoxins: Toxins from prokaryotic blue-green algae with immense impact. Toxicon 2018. [DOI: 10.1016/j.toxicon.2018.02.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|
8
|
Liu T, Mazmouz R, Neilan BA. An In Vitro and In Vivo Study of Broad-Range Phosphopantetheinyl Transferases for Heterologous Expression of Cyanobacterial Natural Products. ACS Synth Biol 2018; 7:1143-1151. [PMID: 29562128 DOI: 10.1021/acssynbio.8b00091] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phosphopantetheinyl transferases catalyze the post-translational modification of carrier proteins involved in both primary and secondary metabolism. The functional expression of polyketide synthases and nonribosomal peptide synthetases requires the activation of all carrier protein domains by phosphopantetheinyl transferases. Here we describe the characterization of five bacterial phosphopantetheinyl transferases by their substrate specificity and catalytic efficiency of four cyanobacterial carrier proteins. Comparative in vitro phosphopantetheinylation analysis showed Sfp possesses the highest catalytic efficiency over various carrier proteins. In vivo coexpression of phosphopantetheinyl transferases with carrier proteins revealed a broad range substrate specificity of phosphopantetheinyl transferases; all studied phosphopantetheinyl transferases were capable of converting apo- carrier proteins, sourced from diverse biosynthetic enzymes, to their active holo form. Phosphopantetheinyl transferase coexpression with the hybrid nonribosomal peptide synthetases/polyketide synthases responsible for microcystin biosynthesis confirmed that the higher in vitro activity of Sfp translated in vivo to a higher yield of production.
Collapse
Affiliation(s)
- Tianzhe Liu
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Rabia Mazmouz
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Brett A. Neilan
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia
| |
Collapse
|
9
|
Liu T, Mazmouz R, Ongley SE, Chau R, Pickford R, Woodhouse JN, Neilan BA. Directing the Heterologous Production of Specific Cyanobacterial Toxin Variants. ACS Chem Biol 2017; 12:2021-2029. [PMID: 28570054 DOI: 10.1021/acschembio.7b00181] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Microcystins are globally the most commonly occurring freshwater cyanotoxins, causing acute poisoning and chronically inducing hepatocellular carcinoma. However, the detection and toxicological study of microcystins is hampered by the limited availability and high cost of pure toxin standards. Biosynthesis of microcystin variants in a fast-growing heterologous host offers a promising method of achieving reliable and economically viable alternative to isolating toxin from slow-growing cyanobacterial cultures. Here, we report the heterologous expression of recombinant microcystin synthetases in Escherichia coli to produce [d-Asp3]microcystin-LR and microcystin-LR. We assembled a 55 kb hybrid polyketide synthase/nonribosomal peptide synthetase gene cluster from Microcystis aeruginosa PCC 7806 using Red/ET recombineering and replaced the native promoters with an inducible PtetO promoter to yield microcystin titers superior to M. aeruginosa. The expression platform described herein can be tailored to heterologously produce a wide variety of microcystin variants, and potentially other cyanobacterial natural products of commercial relevance.
Collapse
Affiliation(s)
- Tianzhe Liu
- School
of Biotechnology and Biomolecular Sciences, The University of New South Wales, New South Wales 2052, Sydney, Australia
| | - Rabia Mazmouz
- School
of Biotechnology and Biomolecular Sciences, The University of New South Wales, New South Wales 2052, Sydney, Australia
- School
of Environmental and Life Sciences, The University of Newcastle, New
South Wales 2308, Callaghan, Australia
| | - Sarah E. Ongley
- School
of Biotechnology and Biomolecular Sciences, The University of New South Wales, New South Wales 2052, Sydney, Australia
- School
of Environmental and Life Sciences, The University of Newcastle, New
South Wales 2308, Callaghan, Australia
| | - Rocky Chau
- School
of Biotechnology and Biomolecular Sciences, The University of New South Wales, New South Wales 2052, Sydney, Australia
| | - Russell Pickford
- Bioanalytical
Mass Spectrometry Facility, The University of New South Wales, New
South Wales 2052, Sydney, Australia
| | - Jason N. Woodhouse
- School
of Biotechnology and Biomolecular Sciences, The University of New South Wales, New South Wales 2052, Sydney, Australia
- Leibniz
Institute of Freshwater Ecology and Inland Fisheries (IGB), Experimental Limnology, 12587, Berlin, Germany
| | - Brett A. Neilan
- School
of Biotechnology and Biomolecular Sciences, The University of New South Wales, New South Wales 2052, Sydney, Australia
- School
of Environmental and Life Sciences, The University of Newcastle, New
South Wales 2308, Callaghan, Australia
| |
Collapse
|
10
|
Pearson LA, Dittmann E, Mazmouz R, Ongley SE, D'Agostino PM, Neilan BA. The genetics, biosynthesis and regulation of toxic specialized metabolites of cyanobacteria. Harmful Algae 2016; 54:98-111. [PMID: 28073484 DOI: 10.1016/j.hal.2015.11.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 11/06/2015] [Indexed: 05/28/2023]
Abstract
The production of toxic metabolites by cyanobacterial blooms represents a significant threat to the health of humans and ecosystems worldwide. Here we summarize the current state of the knowledge regarding the genetics, biosynthesis and regulation of well-characterized cyanotoxins, including the microcystins, nodularin, cylindrospermopsin, saxitoxins and anatoxins, as well as the lesser-known marine toxins (e.g. lyngbyatoxin, aplysiatoxin, jamaicamides, barbamide, curacin, hectochlorin and apratoxins).
Collapse
Affiliation(s)
- Leanne A Pearson
- Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney 2052, NSW, Australia
| | - Elke Dittmann
- Institut für Biochemie und Biologie, Mikrobiologie, Universität Potsdam, Potsdam-Golm 14476, Germany
| | - Rabia Mazmouz
- Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney 2052, NSW, Australia
| | - Sarah E Ongley
- Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney 2052, NSW, Australia
| | - Paul M D'Agostino
- Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney 2052, NSW, Australia
| | - Brett A Neilan
- Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney 2052, NSW, Australia.
| |
Collapse
|
11
|
Méjean A, Mazmouz R, Paci G, Moncoq K, Regad L, Combes A, Pichon V, Ploux O. 6. Biosynthesis of the cyanobacterial neurotoxins anatoxin-a and homoanatoxin-a: From the genome to the metabolites. Toxicon 2014. [DOI: 10.1016/j.toxicon.2014.08.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
12
|
Mann S, Cohen M, Chapuis-Hugon F, Pichon V, Mazmouz R, Méjean A, Ploux O. Synthesis, configuration assignment, and simultaneous quantification by liquid chromatography coupled to tandem mass spectrometry, of dihydroanatoxin-a and dihydrohomoanatoxin-a together with the parent toxins, in axenic cyanobacterial strains and in environmental samples. Toxicon 2012; 60:1404-14. [DOI: 10.1016/j.toxicon.2012.10.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 09/04/2012] [Accepted: 10/10/2012] [Indexed: 11/26/2022]
|
13
|
Mazmouz R, Chapuis-Hugon F, Pichon V, Méjean A, Ploux O. The Last Step of the Biosynthesis of the Cyanotoxins Cylindrospermopsin and 7-epi-Cylindrospermopsin is Catalysed by CyrI, a 2-Oxoglutarate-Dependent Iron Oxygenase. Chembiochem 2011; 12:858-62. [DOI: 10.1002/cbic.201000726] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Indexed: 11/11/2022]
|
14
|
Maïga-Ascofaré O, Le Bras J, Mazmouz R, Renard E, Falcão S, Broussier E, Bustos D, Randrianarivelojosia M, Omar SA, Aubouy A, Lepère JF, Jean-François V, Djimdé AA, Clain J. Adaptive differentiation of Plasmodium falciparum populations inferred from single-nucleotide polymorphisms (SNPs) conferring drug resistance and from neutral SNPs. J Infect Dis 2010; 202:1095-103. [PMID: 20726766 DOI: 10.1086/656142] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Theoretical and experimental data support the geographic differentiation strategy as a valuable tool for detecting loci under selection. In the context of Plasmodium falciparum malaria, few populations have been studied, with limited genomic coverage. METHODS We examined geographic differentiation in P. falciparum populations on the basis of 12 single-nucleotide polymorphisms (SNPs) in 4 genes encoding drug resistance determinants, 5 SNPs in 2 genes encoding antigens, and a set of 17 putatively neutral SNPs dispersed on 13 chromosomes. We sampled 326 parasite isolates representing 7 P. falciparum populations from regions with varied levels of malaria transmission (Gabon, Kenya, Madagascar, Mali, Mayotte, Haiti, and the Philippines). RESULTS Frequencies of drug resistance alleles varied considerably among populations (mean F(ST), 0.52). In contrast, allele frequencies varied significantly less for antigenic and neutral SNPs (mean F(ST), 0.16 and 0.24, respectively). This contrasting pattern was more pronounced when only the African populations were considered. Signature of selection was detected for most of the resistant SNPs but not for the antigenic SNPs. CONCLUSION These data further validate the utility of geographic differentiation for identifying loci under strong positive selection, such as drug resistance loci. This study also provides frequencies of molecular makers of resistance in some overlooked populations.
Collapse
Affiliation(s)
- Oumou Maïga-Ascofaré
- Unité Mixte de Recherche 216, Institut de Recherche pour le Développement, Mère et Enfant Face aux Infections Tropicales, Université Paris Descartes, Paris, France
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Mazmouz R, Chapuis-Hugon F, Mann S, Pichon V, Méjean A, Ploux O. Biosynthesis of cylindrospermopsin and 7-epicylindrospermopsin in Oscillatoria sp. strain PCC 6506: identification of the cyr gene cluster and toxin analysis. Appl Environ Microbiol 2010; 76:4943-9. [PMID: 20525864 PMCID: PMC2916468 DOI: 10.1128/aem.00717-10] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 05/25/2010] [Indexed: 11/20/2022] Open
Abstract
Cylindrospermopsin is a cytotoxin produced by Cylindrospermopsis raciborskii and other cyanobacteria that has been implicated in human intoxications. We report here the complete sequence of the gene cluster responsible for the biosynthesis of this toxin in Oscillatoria sp. strain PCC 6506. This cluster of genes was found to be homologous with that of C. raciborskii but with a different gene organization. Using an enzyme-linked immunosorbent assay and an optimized liquid chromatography analytical method coupled to tandem mass spectrometry, we detected 7-epicylindrospermopsin, cylindrospermopsin, and 7-deoxycylindrospermopsin in the culture medium of axenic Oscillatoria PCC 6506 at the following relative concentrations: 68.6%, 30.2%, and 1.2%, respectively. We measured the intracellular and extracellular concentrations, per mg of dried cells of Oscillatoria PCC 6506, of 7-epicylindrospermopsin (0.18 microg/mg and 0.29 microg/mg, respectively) and cylindrospermopsin (0.10 microg/mg and 0.11 microg/mg, respectively). We showed that these two toxins accumulated in the culture medium of Oscillatoria PCC 6506 but that the ratio (2.5 +/- 0.3) was constant with 7-epicylindrospermopsin being the major metabolite. We also determined the concentrations of these toxins in culture media of other Oscillatoria strains, PCC 6407, PCC 6602, PCC 7926, and PCC 10702, and found that, except for PCC 6602, they all produced 7-epicylindrospermopsin and cylindrospermopsin, with the former being the major toxin, except for PCC 7926, which produced very little 7-epicylindrospermopsin. All the cylindrospermopsin producers studied gave a PCR product using specific primers for the amplification of the cyrJ gene from genomic DNA.
Collapse
Affiliation(s)
- Rabia Mazmouz
- Laboratoire Charles Friedel, UMR CNRS 7223, ENSCP ChimieParisTech, 11 Rue Pierre et Marie Curie, 75231 Paris Cedex 05, France, Université Paris Diderot-Paris 7, 75013 Paris, France, Laboratoire Environnement et Chimie Analytique, UMR PECSA CNRS 7195, ESPCI ParisTech, 10 Rue Vauquelin, 75231 Paris Cedex 05, France
| | - Florence Chapuis-Hugon
- Laboratoire Charles Friedel, UMR CNRS 7223, ENSCP ChimieParisTech, 11 Rue Pierre et Marie Curie, 75231 Paris Cedex 05, France, Université Paris Diderot-Paris 7, 75013 Paris, France, Laboratoire Environnement et Chimie Analytique, UMR PECSA CNRS 7195, ESPCI ParisTech, 10 Rue Vauquelin, 75231 Paris Cedex 05, France
| | - Stéphane Mann
- Laboratoire Charles Friedel, UMR CNRS 7223, ENSCP ChimieParisTech, 11 Rue Pierre et Marie Curie, 75231 Paris Cedex 05, France, Université Paris Diderot-Paris 7, 75013 Paris, France, Laboratoire Environnement et Chimie Analytique, UMR PECSA CNRS 7195, ESPCI ParisTech, 10 Rue Vauquelin, 75231 Paris Cedex 05, France
| | - Valérie Pichon
- Laboratoire Charles Friedel, UMR CNRS 7223, ENSCP ChimieParisTech, 11 Rue Pierre et Marie Curie, 75231 Paris Cedex 05, France, Université Paris Diderot-Paris 7, 75013 Paris, France, Laboratoire Environnement et Chimie Analytique, UMR PECSA CNRS 7195, ESPCI ParisTech, 10 Rue Vauquelin, 75231 Paris Cedex 05, France
| | - Annick Méjean
- Laboratoire Charles Friedel, UMR CNRS 7223, ENSCP ChimieParisTech, 11 Rue Pierre et Marie Curie, 75231 Paris Cedex 05, France, Université Paris Diderot-Paris 7, 75013 Paris, France, Laboratoire Environnement et Chimie Analytique, UMR PECSA CNRS 7195, ESPCI ParisTech, 10 Rue Vauquelin, 75231 Paris Cedex 05, France
| | - Olivier Ploux
- Laboratoire Charles Friedel, UMR CNRS 7223, ENSCP ChimieParisTech, 11 Rue Pierre et Marie Curie, 75231 Paris Cedex 05, France, Université Paris Diderot-Paris 7, 75013 Paris, France, Laboratoire Environnement et Chimie Analytique, UMR PECSA CNRS 7195, ESPCI ParisTech, 10 Rue Vauquelin, 75231 Paris Cedex 05, France
| |
Collapse
|