201
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Visser PM, Verspagen JMH, Sandrini G, Stal LJ, Matthijs HCP, Davis TW, Paerl HW, Huisman J. How rising CO 2 and global warming may stimulate harmful cyanobacterial blooms. HARMFUL ALGAE 2016; 54:145-159. [PMID: 28073473 DOI: 10.1016/j.hal.2015.12.006] [Citation(s) in RCA: 249] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 12/16/2015] [Indexed: 05/21/2023]
Abstract
Climate change is likely to stimulate the development of harmful cyanobacterial blooms in eutrophic waters, with negative consequences for water quality of many lakes, reservoirs and brackish ecosystems across the globe. In addition to effects of temperature and eutrophication, recent research has shed new light on the possible implications of rising atmospheric CO2 concentrations. Depletion of dissolved CO2 by dense cyanobacterial blooms creates a concentration gradient across the air-water interface. A steeper gradient at elevated atmospheric CO2 concentrations will lead to a greater influx of CO2, which can be intercepted by surface-dwelling blooms, thus intensifying cyanobacterial blooms in eutrophic waters. Bloom-forming cyanobacteria display an unexpected diversity in CO2 responses, because different strains combine their uptake systems for CO2 and bicarbonate in different ways. The genetic composition of cyanobacterial blooms may therefore shift. In particular, strains with high-flux carbon uptake systems may benefit from the anticipated rise in inorganic carbon availability. Increasing temperatures also stimulate cyanobacterial growth. Many bloom-forming cyanobacteria and also green algae have temperature optima above 25°C, often exceeding the temperature optima of diatoms and dinoflagellates. Analysis of published data suggests that the temperature dependence of the growth rate of cyanobacteria exceeds that of green algae. Indirect effects of elevated temperature, like an earlier onset and longer duration of thermal stratification, may also shift the competitive balance in favor of buoyant cyanobacteria while eukaryotic algae are impaired by higher sedimentation losses. Furthermore, cyanobacteria differ from eukaryotic algae in that they can fix dinitrogen, and new insights show that the nitrogen-fixation activity of heterocystous cyanobacteria can be strongly stimulated at elevated temperatures. Models and lake studies indicate that the response of cyanobacterial growth to rising CO2 concentrations and elevated temperatures can be suppressed by nutrient limitation. The greatest response of cyanobacterial blooms to climate change is therefore expected to occur in eutrophic and hypertrophic lakes.
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Affiliation(s)
- Petra M Visser
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94248, 1090 GE Amsterdam, The Netherlands.
| | - Jolanda M H Verspagen
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94248, 1090 GE Amsterdam, The Netherlands
| | - Giovanni Sandrini
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94248, 1090 GE Amsterdam, The Netherlands
| | - Lucas J Stal
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94248, 1090 GE Amsterdam, The Netherlands; Department of Marine Microbiology, Royal Netherlands Institute for Sea Research (NIOZ), P.O. Box 140, 4400 AC Yerseke, The Netherlands
| | - Hans C P Matthijs
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94248, 1090 GE Amsterdam, The Netherlands
| | - Timothy W Davis
- NOAA Great Lakes Environmental Research Laboratory, Ann Arbor, MI 48108, USA
| | - Hans W Paerl
- Institute of Marine Sciences, University of North Carolina at Chapel Hill, 3431 Arendell Street, Morehead City, NC 28557, USA
| | - Jef Huisman
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94248, 1090 GE Amsterdam, The Netherlands
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202
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Gobler CJ, Burkholder JM, Davis TW, Harke MJ, Johengen T, Stow CA, Van de Waal DB. The dual role of nitrogen supply in controlling the growth and toxicity of cyanobacterial blooms. HARMFUL ALGAE 2016; 54:87-97. [PMID: 28073483 DOI: 10.1016/j.hal.2016.01.010] [Citation(s) in RCA: 179] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 01/30/2016] [Indexed: 05/03/2023]
Abstract
Historically, phosphorus (P) has been considered the primary limiting nutrient for phytoplankton assemblages in freshwater ecosystems. This review, supported by new findings from Lake Erie, highlights recent molecular, laboratory, and field evidence that the growth and toxicity of some non-diazotrophic blooms of cyanobacteria can be controlled by nitrogen (N). Cyanobacteria such as Microcystis possess physiological adaptations that allow them to dominate low-P surface waters, and in temperate lakes, cyanobacterial densities can be controlled by N availability. Beyond total cyanobacterial biomass, N loading has been shown to selectively promote the abundance of Microcystis and Planktothrix strains capable of synthesizing microcystins over strains that do not possess this ability. Among strains of cyanobacteria capable of synthesizing the N-rich microcystins, cellular toxin quotas have been found to depend upon exogenous N supplies. Herein, multi-year observations from western Lake Erie are presented demonstrating that microcystin concentrations peak in parallel with inorganic N, but not orthophosphate, concentrations and are significantly lower (p<0.01) during years of reduced inorganic nitrogen loading and concentrations. Collectively, this information underscores the importance of N as well as P in controlling toxic cyanobacteria blooms. Furthermore, it supports the premise that management actions to reduce P in the absence of concurrent restrictions on N loading may not effectively control the growth and/or toxicity of non-diazotrophic toxic cyanobacteria such as the cosmopolitan, toxin-producing genus, Microcystis.
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Affiliation(s)
- Christopher J Gobler
- School of Marine and Atmospheric Sciences, Stony Brook University, 239 Montauk Hwy, New York 11968, USA.
| | - JoAnn M Burkholder
- Center for Applied Aquatic Ecology, North Carolina State University, Raleigh, NC 27606, USA
| | - Timothy W Davis
- NOAA Great Lakes Environmental Research Laboratory, Ann Arbor, MI 48108, USA
| | - Matthew J Harke
- School of Marine and Atmospheric Sciences, Stony Brook University, 239 Montauk Hwy, New York 11968, USA
| | - Tom Johengen
- Cooperative Institute for Limnology and Ecosystems Research, University of Michigan, Ann Arbor, MI 48109, USA
| | - Craig A Stow
- NOAA Great Lakes Environmental Research Laboratory, Ann Arbor, MI 48108, USA
| | - Dedmer B Van de Waal
- Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Post Office Box 50, Wageningen 6700 AB, The Netherlands
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203
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Harke MJ, Steffen MM, Gobler CJ, Otten TG, Wilhelm SW, Wood SA, Paerl HW. A review of the global ecology, genomics, and biogeography of the toxic cyanobacterium, Microcystis spp. HARMFUL ALGAE 2016; 54:4-20. [PMID: 28073480 DOI: 10.1016/j.hal.2015.12.007] [Citation(s) in RCA: 520] [Impact Index Per Article: 65.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 12/22/2015] [Indexed: 05/03/2023]
Abstract
This review summarizes the present state of knowledge regarding the toxic, bloom-forming cyanobacterium, Microcystis, with a specific focus on its geographic distribution, toxins, genomics, phylogeny, and ecology. A global analysis found documentation suggesting geographic expansion of Microcystis, with recorded blooms in at least 108 countries, 79 of which have also reported the hepatatoxin microcystin. The production of microcystins (originally "Fast-Death Factor") by Microcystis and factors that control synthesis of this toxin are reviewed, as well as the putative ecophysiological roles of this metabolite. Molecular biological analyses have provided significant insight into the ecology and physiology of Microcystis, as well as revealed the highly dynamic, and potentially unstable, nature of its genome. A genetic sequence analysis of 27 Microcystis species, including 15 complete/draft genomes are presented. Using the strictest biological definition of what constitutes a bacterial species, these analyses indicate that all Microcystis species warrant placement into the same species complex since the average nucleotide identity values were above 95%, 16S rRNA nucleotide identity scores exceeded 99%, and DNA-DNA hybridization was consistently greater than 70%. The review further provides evidence from around the globe for the key role that both nitrogen and phosphorus play in controlling Microcystis bloom dynamics, and the effect of elevated temperature on bloom intensification. Finally, highlighted is the ability of Microcystis assemblages to minimize their mortality losses by resisting grazing by zooplankton and bivalves, as well as viral lysis, and discuss factors facilitating assemblage resilience.
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Affiliation(s)
- Matthew J Harke
- Department of Earth and Environmental Sciences, Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, United States
| | - Morgan M Steffen
- James Madison University, Department of Biology, 951 Carrier Dr., Harrisonburg, VA 22807, United States.
| | - Christopher J Gobler
- Stony Brook University, School of Marine and Atmospheric Sciences, 239 Montauk Hwy, Southampton, NY 11968, United States
| | - Timothy G Otten
- Oregon State University, Department of Microbiology, Nash Hall 226, Corvallis, OR 97331, United States
| | - Steven W Wilhelm
- University of Tennessee, Department of Microbiology, 1414 West Cumberland Ave., Knoxville, TN 37996, United States
| | - Susanna A Wood
- Cawthron Institute, Private Bag 2, Nelson, New Zealand and Environmental Research Institute, University of Waikato, Hamilton, New Zealand
| | - Hans W Paerl
- University of North Carolina at Chapel Hill, Institute of Marine Sciences, 3431 Arendell Street, Morehead City, NC 28557, United States
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204
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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] [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).
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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.
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205
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González A, Sevilla E, Bes MT, Peleato ML, Fillat MF. Pivotal Role of Iron in the Regulation of Cyanobacterial Electron Transport. Adv Microb Physiol 2016; 68:169-217. [PMID: 27134024 DOI: 10.1016/bs.ampbs.2016.02.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Iron-containing metalloproteins are the main cornerstones for efficient electron transport in biological systems. The abundance and diversity of iron-dependent proteins in cyanobacteria makes those organisms highly dependent of this micronutrient. To cope with iron imbalance, cyanobacteria have developed a survey of adaptation strategies that are strongly related to the regulation of photosynthesis, nitrogen metabolism and other central electron transfer pathways. Furthermore, either in its ferrous form or as a component of the haem group, iron plays a crucial role as regulatory signalling molecule that directly or indirectly modulates the composition and efficiency of cyanobacterial redox reactions. We present here the major mechanism used by cyanobacteria to couple iron homeostasis to the regulation of electron transport, making special emphasis in processes specific in those organisms.
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Affiliation(s)
| | - E Sevilla
- University of Zaragoza, Zaragoza, Spain
| | - M T Bes
- University of Zaragoza, Zaragoza, Spain
| | | | - M F Fillat
- University of Zaragoza, Zaragoza, Spain.
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206
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Manganelli M, Stefanelli M, Vichi S, Andreani P, Nascetti G, Scialanca F, Scardala S, Testai E, Funari E. Cyanobacteria biennal dynamic in a volcanic mesotrophic lake in central Italy: Strategies to prevent dangerous human exposures to cyanotoxins. Toxicon 2016; 115:28-40. [PMID: 26948426 DOI: 10.1016/j.toxicon.2016.03.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 02/29/2016] [Accepted: 03/03/2016] [Indexed: 10/22/2022]
Abstract
Vico Lake, a volcanic meso-eutrophic lake in Central Italy, whose water is used for drinking and recreational activities, experienced the presence of the microcystins (MC) producing cyanobacterium Planktothrix rubescens. In order to assess the human health risks and to provide the local health authorities with a scientific basis for planning tailored monitoring activities, we studied P. rubescens ecology and toxicity for two years. P. rubescens generally dominated the phytoplankton community, alternating with Limnothrix redekei, potentially toxic. P. rubescens was distributed throughout the water column during winter; in summer it produced intense blooms where drinking water is collected (-20 m); here MC were detected all year round (0.5-5 μg/L), with implications for drinking water quality. In surface waters, MC posed no risk for recreational activities in summer, while in winter surface blooms and foams (containing up to 56 μg MC/L) can represent a risk for people and children practicing water sports and for animals consuming raw water. Total phosphorus, phosphate and inorganic nitrogen were not relevant to predict densities nor toxicity; however, a strong correlation between P. rubescens density and aminopeptidase ectoenzymatic activity, an enzyme involved in protein degradation, suggested a role of organic nitrogen for this species. The fraction of potentially toxic population, determined both as mcyB(+)/16SrDNA (10-100%) and as the MC/mcyB(+) cells (0.03-0.79 pg MC/cell), was much more variable than usually observed for P. rubescens. Differently from other Italian and European lakes, the correlation between cell density or the mcyB(+) cells and MC explained only ∼50 and 30% of MC variability, respectively: for Vico Lake, monitoring only cell or the mcyB(+) cell density is not sufficient to predict MC concentrations, and consequently to protect population health. Finally, during a winter bloom one site has been sampled weekly, showing that monthly sampling during such a phase could greatly underestimate the 'hazard'. Our results highlight the need to adopt a stepwise monitoring activity, considering the lake and the cyanobacteria specific features. This activity should be complemented with communication to the public and involvement of stakeholders.
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Affiliation(s)
- Maura Manganelli
- Department of the Environment and Primary Prevention - Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, Italy.
| | - Mara Stefanelli
- Research, Certification and Control Division - INAIL, via Fontana candida 1, Monteporzio Catone, Rome, Italy.
| | - Susanna Vichi
- Department of the Environment and Primary Prevention - Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, Italy.
| | - Paolo Andreani
- Tutela acque - Concessioni e Risorse idriche, Provincia di Viterbo, Via del Collegio, Viterbo, Italy.
| | - Giuseppe Nascetti
- Department of Ecology and Biology - University La Tuscia, via S. Giovanni decollato 1, Viterbo, Italy.
| | - Fabrizio Scialanca
- Department of Ecology and Biology - University La Tuscia, via S. Giovanni decollato 1, Viterbo, Italy.
| | - Simona Scardala
- Department of the Environment and Primary Prevention - Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, Italy.
| | - Emanuela Testai
- Department of the Environment and Primary Prevention - Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, Italy.
| | - Enzo Funari
- Department of the Environment and Primary Prevention - Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, Italy.
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207
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Huang X, Tu Y, Song C, Li T, Lin J, Wu Y, Liu J, Wu C. Interactions between the antimicrobial agent triclosan and the bloom-forming cyanobacteria Microcystis aeruginosa. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 172:103-110. [PMID: 26800489 DOI: 10.1016/j.aquatox.2016.01.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 01/06/2016] [Accepted: 01/07/2016] [Indexed: 06/05/2023]
Abstract
Cyanobacteria can co-exist in eutrophic waters with chemicals or other substances derived from personal care products discharged in wastewater. In this work, we investigate the interactions between the antimicrobial agent triclosan (TCS) and the bloom-forming cyanobacteria Microcystis aeruginosa. M. aeruginosa was very sensitive to TCS with the 96h lowest observed effect concentration of 1.0 and 10μg/L for inhibition of growth and photosynthetic activity, respectively. Exposure to TCS at environmentally relevant levels (0.1-2.0μg/L) also affected the activities of superoxide dismutase (SOD) and the generation of reduced glutathione (GSH), while microcystin production was not affected. Transmission electron microscope (TEM) examination showed the destruction of M. aeruginosa cell ultrastructure during TCS exposure. TCS however, can be biotransformed by M. aeruginosa with methylation as a major biotransformation pathway. Furthermore, the presence of M. aeruginosa in solution promoted the photodegradation of TCS. Overall, our results demonstrate that M. aeruginosa plays an important role in the dissipation of TCS in aquatic environments but high residual TCS can exert toxic effects on M. aeruginosa.
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Affiliation(s)
- Xiaolong Huang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; Wuhan Zhongke Hydrobiological Environment Engineering Co., Ltd, Wuhan 430071, China
| | - Yenan Tu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; Graduate University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Chaofeng Song
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; Graduate University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Tiancui Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; Graduate University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Juan Lin
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; Graduate University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Yonghong Wu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Sciences, Chinese Academy of Sciences, Nanjing 210008, China
| | - Jiantong Liu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Chenxi Wu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
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208
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Zhu L, Zuo J, Song L, Gan N. Microcystin-degrading bacteria affect mcyD expression and microcystin synthesis in Microcystis spp. J Environ Sci (China) 2016; 41:195-201. [PMID: 26969065 DOI: 10.1016/j.jes.2015.06.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 06/17/2015] [Accepted: 06/20/2015] [Indexed: 06/05/2023]
Abstract
Cyanobacterial blooms occur increasingly often and cause ecological, economic and human health problems worldwide. Microcystins (MCs) are the dominant toxins produced by cyanobacteria and are implicated in epidemic disease and environmental problems. Extensive research has been reported on the various regulating factors, e.g., light, temperature, nutrients such as nitrogen and phosphorus, pH, iron, xenobiotics, and predators, that influence microcystin (MC) synthesis, but little is known about the effects of cyanobacteria-associated bacteria on MC synthesis. A considerable number of studies have focused on interactions between Microcystis species and their associated bacteria. In this study, we evaluated the effects of MC-degrading bacteria (MCDB) on MC synthesis gene mcyD expression and MC synthesis in axenic strain PCC7806, non-axenic strain FACHB905, and colony strain FACHB1325 of Microcystis by quantitative real-time polymerase chain reaction (RT-PCR) assay and enzyme-linked immunosorbent assay (ELISA). We demonstrate for the first time that MCDB can induce and up-regulate the MC production and transcriptional response of the mcyD gene of toxic Microcystis. On day 4 of the culturing experiment, the intracellular MC concentration and transcriptional response of mcyD of FACHB1325 were up-regulated 1.9 and 5.3-fold over that of the control, and for FACHB905 were up-regulated 1.8 and 4.2-fold over that of the control, respectively. On day 10, the transcriptional response of mcyD was up-regulated 21.3-fold in PCC7806. These results indicate that there are interactions between toxic Microcystis and MCDB, and MCDB may play a role in regulating mcyD expression in toxic Microcystis.
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Affiliation(s)
- Lin Zhu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
| | - Jun Zuo
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lirong Song
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
| | - Nanqin Gan
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
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209
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Chen L, Gin KYH, He Y. Effects of sulfate on microcystin production, photosynthesis, and oxidative stress in Microcystis aeruginosa. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:3586-3595. [PMID: 26490939 DOI: 10.1007/s11356-015-5605-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 10/12/2015] [Indexed: 06/05/2023]
Abstract
Increasing sulfate in freshwater systems, caused by human activities and climate change, may have negative effects on aquatic organisms. Microcystis aeruginosa (M. aeruginosa) is both a major primary producer and a common toxic cyanobacterium, playing an important role in the aquatic environment. This study first investigated the effects of sulfate on M. aeruginosa. The experiment presented here aims at analyzing the effects of sulfate on physiological indices, molecular levels, and its influencing mechanism. The results of our experiment showed that sulfate (at 40, 80, and 300 mg L(-1)) inhibited M. aeruginosa growth, increased both intracellular and extracellular toxin contents, and enhanced the mcyD transcript level. Sulfate inhibited the photosynthesis of M. aeruginosa, based on the decrease in pigment content and the down-regulation of photosynthesis-related genes after sulfate exposure. Furthermore, sulfate decreased the maximum electron transport rate, causing the cell to accumulate surplus electrons and form reactive oxygen species (ROS). Sulfate also increased the malondialdehyde (MDA) content, which showed that sulfate damaged the cytomembrane. This damage contributed to the release of intracellular toxin to the culture medium. Although sulfate increased superoxide dismutase (SOD) activities, expression of sod, and total antioxidant capacity in M. aeruginosa, it still overwhelmed the antioxidant system since the ROS level simultaneously increased, and finally caused oxidative stress. Our results indicate that sulfate has direct effects on M. aeruginosa, inhibits photosynthesis, causes oxidative stress, increases toxin production, and affects the related genes expression in M. aeruginosa.
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Affiliation(s)
- Lei Chen
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China
| | - Karina Y H Gin
- Department of Civil & Environmental Engineering, National University of Singapore, Engineering Drive 2, E1A-07-03, Singapore, 117576, Singapore
| | - Yiliang He
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China.
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210
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D'Agostino PM, Woodhouse JN, Makower AK, Yeung ACY, Ongley SE, Micallef ML, Moffitt MC, Neilan BA. Advances in genomics, transcriptomics and proteomics of toxin-producing cyanobacteria. ENVIRONMENTAL MICROBIOLOGY REPORTS 2016; 8:3-13. [PMID: 26663762 DOI: 10.1111/1758-2229.12366] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 11/10/2015] [Accepted: 12/05/2015] [Indexed: 06/05/2023]
Abstract
A common misconception persists that the genomes of toxic and non-toxic cyanobacterial strains are largely conserved with the exception of the presence or absence of the genes responsible for toxin production. Implementation of -omics era technologies has challenged this paradigm, with comparative analyses providing increased insight into the differences between strains of the same species. The implementation of genomic, transcriptomic and proteomic approaches has revealed distinct profiles between toxin-producing and non-toxic strains. Further, metagenomics and metaproteomics highlight the genomic potential and functional state of toxic bloom events over time. In this review, we highlight how these technologies have shaped our understanding of the complex relationship between these molecules, their producers and the environment at large within which they persist.
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Affiliation(s)
- Paul M D'Agostino
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Biological Sciences Building D26, Sydney, NSW, 2052, Australia
| | - Jason N Woodhouse
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Biological Sciences Building D26, Sydney, NSW, 2052, Australia
| | - A Katharina Makower
- Department of Microbiology, Institute for Biochemistry and Biology, University of Potsdam, Potsdam-Golm, 14476, Germany
| | - Anna C Y Yeung
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Biological Sciences Building D26, Sydney, NSW, 2052, Australia
| | - Sarah E Ongley
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Biological Sciences Building D26, Sydney, NSW, 2052, Australia
| | - Melinda L Micallef
- School of Science and Health, University of Western Sydney, Sydney, NSW, 2571, Australia
| | - Michelle C Moffitt
- School of Science and Health, University of Western Sydney, Sydney, NSW, 2571, Australia
| | - Brett A Neilan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Biological Sciences Building D26, Sydney, NSW, 2052, Australia
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211
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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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212
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Harke MJ, Gobler CJ. Daily transcriptome changes reveal the role of nitrogen in controlling microcystin synthesis and nutrient transport in the toxic cyanobacterium, Microcystis aeruginosa. BMC Genomics 2015; 16:1068. [PMID: 26673568 PMCID: PMC4681089 DOI: 10.1186/s12864-015-2275-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 12/03/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND While transcriptomics have become a valuable tool for linking physiology and ecology in aquatic microbes, the temporal dynamics of global transcriptomic patterns in Microcystis have rarely been assessed. Furthermore, while many microbial studies have explored expression of nutrient transporter genes, few studies have concurrently measured nutrient assimilation rates. Here, we considered how the global transcriptomic patterns and physiology of the cyanobacterium, Microcystis aeruginosa, changed daily as cells were grown from replete to deficient nitrogen (N) conditions and then back to replete conditions. RESULTS During N deprivation, Microcystis downregulated genes involved in photosynthesis and respiration, carbon acquisition, lipid metabolism, and amino acid biosynthesis while upregulating genes involved in N acquisition and transport. With increasing N stress, both the strength of expression and number of genes being differentially expressed increased, until N was restored at which point these patterns reversed. Uptake of (15)N-labeled nitrate, ammonium and urea reflected differential expression of genes encoding transporters for these nutrients, with Microcystis appearing to preferentially increase transcription of ammonium and urea transporters and uptake of these compounds during N deprivation. Nitrate uptake and nitrate transporter expression were correlated for one set of transporters but not another, indicating these were high and low affinity nitrate transporters, respectively. Concentrations of microcystin per cell decreased during N deprivation and increased upon N restoration. However, the transcript abundance of genes involved in the synthesis of this compound was complex, as microcystin synthetase genes involved in peptide synthesis were downregulated under N deprivation while genes involved in tailoring and transport were upregulated, suggesting modification of the microcystin molecule under N stress as well as potential alternative functions for these genes and/or this toxin. CONCLUSIONS Collectively, this study highlights the complex choreography of gene expression, cell physiology, and toxin synthesis that dynamic N levels can elicit in this ecologically important cyanobacterium. Differing expression patterns of genes within the microcystin synthetase operon in response to changing N levels revealed the potential limitations drawing conclusions based on only one gene in this operon.
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Affiliation(s)
- Matthew J Harke
- School of Marine and Atmospheric Sciences, Stony Brook University, 239 Montauk Hwy, Southampton, NY, 11968, USA.
| | - Christopher J Gobler
- School of Marine and Atmospheric Sciences, Stony Brook University, 239 Montauk Hwy, Southampton, NY, 11968, USA.
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Liu J, Van Oosterhout E, Faassen EJ, Lürling M, Helmsing NR, Van de Waal DB. ElevatedpCO2causes a shift towards more toxic microcystin variants in nitrogen-limitedMicrocystis aeruginosa. FEMS Microbiol Ecol 2015; 92:fiv159. [DOI: 10.1093/femsec/fiv159] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/10/2015] [Indexed: 11/12/2022] Open
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214
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Švanys A, Eigemann F, Grossart HP, Hilt S. Microcystins do not necessarily lower the sensitivity of Microcystis aeruginosa to tannic acid. FEMS Microbiol Lett 2015; 363:fnv227. [PMID: 26613927 DOI: 10.1093/femsle/fnv227] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2015] [Indexed: 11/12/2022] Open
Abstract
Different phytoplankton strains have been shown to possess varying sensitivities towards macrophyte allelochemicals, yet the reasons for this are largely unknown. To test whether microcystin (MC) is responsible for strain-specific sensitivities of Microcystis aeruginosa to macrophyte allelochemicals, we compared the sensitivity of 12 MC- and non-MC-producing M. aeruginosa strains, including an MC-deficient mutant and its wild type, to the polyphenolic allelochemical tannic acid (TA). Non-MC-producing strains showed a significantly higher sensitivity to TA than MC-producing strains, both in Chlorophyll a concentrations and quantum yields of photosystem II. In contrast, an MC-deficient mutant displayed a higher fitness against TA compared to its wild type. These results suggest that the resistance of M. aeruginosa to polyphenolic allelochemicals is not primarily related to MCs per se, but to other yet unknown protective mechanisms related to MCs.
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Affiliation(s)
- Algirdas Švanys
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Department of Ecosystem Research, Müggelseedamm 301, D-12587 Berlin, Germany Marine Science and Technology Center, Klaipėda University, H. Manto 84, 92294 Klaipėda, Lithuania
| | - Falk Eigemann
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Department of Ecosystem Research, Müggelseedamm 301, D-12587 Berlin, Germany Leibniz-Institute for Baltic Sea Research Warnemünde, Department of Biological Oceanography, Seestraße 15, D-18119 Rostock, Germany
| | - Hans-Peter Grossart
- Leibniz-Institute for Freshwater Ecology and Inland Fisheries, Department of Limnology of Stratified Lakes, Alte Fischerhütte 2, D-16775 Stechlin, Germany Potsdam University, Institute of Biochemistry and Biology, Maulbeerallee 10, D-14469 Potsdam, Germany
| | - Sabine Hilt
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Department of Ecosystem Research, Müggelseedamm 301, D-12587 Berlin, Germany
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215
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Geh EN, Ghosh D, McKell M, de la Cruz AA, Stelma G, Bernstein JA. Identification of Microcystis aeruginosa Peptides Responsible for Allergic Sensitization and Characterization of Functional Interactions between Cyanobacterial Toxins and Immunogenic Peptides. ENVIRONMENTAL HEALTH PERSPECTIVES 2015; 123:1159-66. [PMID: 25902363 PMCID: PMC4629744 DOI: 10.1289/ehp.1409065] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 04/15/2015] [Indexed: 05/27/2023]
Abstract
BACKGROUND The cyanobacterium species Microcystis aeruginosa produces microcystin and an array of diverse metabolites believed responsible for their toxicity and/or immunogenicity. Previously, chronic rhinitis patients were demonstrated to elicit a specific IgE response to nontoxic strains of M. aeruginosa by skin-prick testing, indicating that cyanobacteria allergenicity resides in a non-toxin-producing component of the organism. OBJECTIVES We sought to identify and characterize M. aeruginosa peptide(s) responsible for allergic sensitization in susceptible individuals, and we investigated the functional interactions between cyanobacterial toxins and their coexpressed immunogenic peptides. METHODS Sera from patients and extracts from M. aeruginosa toxic [MC(+)] and nontoxic [MC(-)] strains were used to test IgE-specific reactivity by direct and indirect ELISAs; 2D gel electrophoresis, followed by immunoblots and mass spectrometry (MS), was performed to identify the relevant sensitizing peptides. Cytotoxicity and mediator release assays were performed using the MC(+) and MC(-) lysates. RESULTS We found specific IgE to be increased more in response to the MC(-) strain than the MC(+) strain. This response was inhibited by preincubation of MC(-) lysate with increasing concentrations of microcystin. MS revealed that phycocyanin and the core-membrane linker peptide are the responsible allergens, and MC(-) extracts containing these proteins induced β-hexosaminidase release in rat basophil leukemia cells. CONCLUSIONS Phycobiliprotein complexes in M. aeruginosa have been identified as the relevant sensitizing proteins. Our finding that allergenicity is inhibited in a dose-dependent manner by microcystin toxin suggests that further investigation is warranted to understand the interplay between immunogenicity and toxicity of cyanobacteria under diverse environmental conditions. CITATION Geh EN, Ghosh D, McKell M, de la Cruz AA, Stelma G, Bernstein JA. 2015. Identification of Microcystis aeruginosa peptides responsible for allergic sensitization and characterization of functional interactions between cyanobacterial toxins and immunogenic peptides. Environ Health Perspect 123:1159-1166; http://dx.doi.org/10.1289/ehp.1409065.
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Affiliation(s)
- Esmond N Geh
- Allergy Section, Division of Immunology Allergy, and Rheumatology, Department of Internal Medicine, and
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216
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Sandrini G, Jakupovic D, Matthijs HCP, Huisman J. Strains of the Harmful Cyanobacterium Microcystis aeruginosa Differ in Gene Expression and Activity of Inorganic Carbon Uptake Systems at Elevated CO2 Levels. Appl Environ Microbiol 2015; 81:7730-9. [PMID: 26319871 PMCID: PMC4616958 DOI: 10.1128/aem.02295-15] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 08/22/2015] [Indexed: 11/20/2022] Open
Abstract
Cyanobacteria are generally assumed to be effective competitors at low CO2 levels because of their efficient CO2-concentrating mechanism (CCM), and yet how bloom-forming cyanobacteria respond to rising CO2 concentrations is less clear. Here, we investigate changes in CCM gene expression at ambient CO2 (400 ppm) and elevated CO2 (1,100 ppm) in six strains of the harmful cyanobacterium Microcystis. All strains downregulated cmpA encoding the high-affinity bicarbonate uptake system BCT1, whereas both the low- and high-affinity CO2 uptake genes were expressed constitutively. Four strains downregulated the bicarbonate uptake genes bicA and/or sbtA, whereas two strains showed constitutive expression of the bicA-sbtA operon. In one of the latter strains, a transposon insert in bicA caused low bicA and sbtA transcript levels, which made this strain solely dependent on BCT1 for bicarbonate uptake. Activity measurements of the inorganic carbon (Ci) uptake systems confirmed the CCM gene expression results. Interestingly, genes encoding the RuBisCO enzyme, structural carboxysome components, and carbonic anhydrases were not regulated. Hence, Microcystis mainly regulates the initial uptake of inorganic carbon, which might be an effective strategy for a species experiencing strongly fluctuating Ci concentrations. Our results show that CCM gene regulation of Microcystis varies among strains. The observed genetic and phenotypic variation in CCM responses may offer an important template for natural selection, leading to major changes in the genetic composition of harmful cyanobacterial blooms at elevated CO2.
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Affiliation(s)
- Giovanni Sandrini
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Dennis Jakupovic
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Hans C P Matthijs
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Jef Huisman
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
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217
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Noyma NP, Silva TP, Chiarini-Garcia H, Amado AM, Roland F, Melo RCN. Potential effects of UV radiation on photosynthetic structures of the bloom-forming cyanobacterium Cylindrospermopsis raciborskii CYRF-01. Front Microbiol 2015; 6:1202. [PMID: 26579108 PMCID: PMC4627488 DOI: 10.3389/fmicb.2015.01202] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 10/15/2015] [Indexed: 11/13/2022] Open
Abstract
Cyanobacteria are aquatic photosynthetic microorganisms. While of enormous ecological importance, they have also been linked to human and animal illnesses around the world as a consequence of toxin production by some species. Cylindrospermopsis raciborskii, a filamentous nitrogen-fixing cyanobacterium, has attracted considerable attention due to its potential toxicity and ecophysiological adaptability. We investigated whether C. raciborskii could be affected by ultraviolet (UV) radiation. Non-axenic cultures of C. raciborskii were exposed to three UV treatments (UVA, UVB, or UVA + UVB) over a 6 h period, during which cell concentration, viability and ultrastructure were analyzed. UVA and UVA + UVB treatments showed significant negative effects on cell concentration (decreases of 56.4 and 64.3%, respectively). This decrease was directly associated with cell death as revealed by a cell viability fluorescent probe. Over 90% of UVA + UVB- and UVA-treated cells died. UVB did not alter cell concentration, but reduced cell viability in almost 50% of organisms. Transmission electron microscopy (TEM) revealed a drastic loss of thylakoids, membranes in which cyanobacteria photosystems are localized, after all treatments. Moreover, other photosynthetic- and metabolic-related structures, such as accessory pigments and polyphosphate granules, were damaged. Quantitative TEM analyses revealed a 95.8% reduction in cell area occupied by thylakoids after UVA treatment, and reduction of 77.6 and 81.3% after UVB and UVA + UVB treatments, respectively. Results demonstrated clear alterations in viability and photosynthetic structures of C. raciborskii induced by various UV radiation fractions. This study facilitates our understanding of the subcellular organization of this cyanobacterium species, identifies specific intracellular targets of UVA and UVB radiation and reinforces the importance of UV radiation as an environmental stressor.
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Affiliation(s)
- Natália P Noyma
- Laboratory of Aquatic Ecology, Department of Biology, Federal University of Juiz de Fora Juiz de Fora, Brazil
| | - Thiago P Silva
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora Juiz de Fora, Brazil
| | - Hélio Chiarini-Garcia
- Laboratory of Structural Biology and Reproduction, Department of Morphology, Federal University of Minas Gerais Belo Horizonte, Brazil
| | - André M Amado
- Laboratory of Limnology, Department of Oceanography and Limnology, Federal University of Rio Grande do Norte Natal, Brazil
| | - Fábio Roland
- Laboratory of Aquatic Ecology, Department of Biology, Federal University of Juiz de Fora Juiz de Fora, Brazil
| | - Rossana C N Melo
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora Juiz de Fora, Brazil
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218
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Yang Z, Kong F. UV-B Exposure Affects the Biosynthesis of Microcystin in Toxic Microcystis aeruginosa Cells and Its Degradation in the Extracellular Space. Toxins (Basel) 2015; 7:4238-52. [PMID: 26492272 PMCID: PMC4626732 DOI: 10.3390/toxins7104238] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 10/13/2015] [Accepted: 10/14/2015] [Indexed: 11/16/2022] Open
Abstract
Microcystins (MCs) are cyclic hepatotoxic heptapeptides produced by cyanobacteria that can be toxic to aquatic and terrestrial organisms. MC synthesis and degradation are thought to be influenced by several different physical and environmental parameters. In this study, the effects of different intensities of UV-B radiation on MC biosynthesis in Microcystis cells and on its extracellular degradation were investigated by mRNA analysis and degradation experiments. Exposure to UV-B at intensities of 1.02 and 1.45 W/m2 not only remarkably inhibited the growth of Microcystis, but also led to a decrease in the MC concentration. In addition, mcyD transcription was decreased under the same UV-B intensities. These results demonstrated that the effects of UV-B exposure on the biosynthesis of MCs in Microcystis cells could be attributed to the regulation of mcy gene transcription. Moreover, the MC concentration was decreased significantly after exposure to different intensities of UV-B radiation. Of the three MC variants (MC-LR, -RR and -YR, L, R and Y are abbreviations of leucine, arginine and tyrosine), MC-LR and MC-YR were sensitive to UV-B radiation, whereas MC-RR was not. In summary, our results showed that UV-B radiation had a negative effect on MC production in Microcystis cells and MC persistence in the extracellular space.
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Affiliation(s)
- Zhen Yang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China.
| | - Fanxiang Kong
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China.
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219
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Paerl HW, Otten TG. Duelling 'CyanoHABs': unravelling the environmental drivers controlling dominance and succession among diazotrophic and non-N2 -fixing harmful cyanobacteria. Environ Microbiol 2015; 18:316-24. [PMID: 26310611 DOI: 10.1111/1462-2920.13035] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 08/20/2015] [Indexed: 11/27/2022]
Abstract
Eutrophication often manifests itself by increased frequencies and magnitudes of cyanobacterial harmful algal blooms (CyanoHABs) in freshwater systems. It is generally assumed that nitrogen-fixing cyanobacteria will dominate when nitrogen (N) is limiting and non-N2 fixers dominate when N is present in excess. However, this is rarely observed in temperate lakes, where N2 fixers often bloom when N is replete, and non-fixers (e.g. Microcystis) dominate when N concentrations are lowest. This review integrates observations from previous studies with insights into the environmental factors that select for CyanoHAB groups. This information may be used to predict how nutrient reduction strategies targeting N, phosphorus (P) or both N and P may alter cyanobacterial community composition. One underexplored concern is that as N inputs are reduced, CyanoHABs may switch from non-N2 fixing to diazotrophic taxa, with no net improvement in water quality. However, monitoring and experimental observations indicate that in eutrophic systems, minimizing both N and P loading will lead to the most significant reductions in total phytoplankton biomass without this shift occurring, because successional patterns appear to be strongly driven by physical factors, including temperature, irradiance and hydrology. Notably, water temperature is a primary driver of cyanobacterial community succession, with warming favouring non-diazotrophic taxa.
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Affiliation(s)
- Hans W Paerl
- Institute of Marine Sciences, The University of North Carolina at Chapel Hill, Morehead City, NC, 28557, USA
| | - Timothy G Otten
- Department of Microbiology, Oregon State University, 226 Nash Hall, Corvallis, OR, 97331, USA
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220
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Battchikova N, Angeleri M, Aro EM. Proteomic approaches in research of cyanobacterial photosynthesis. PHOTOSYNTHESIS RESEARCH 2015; 126:47-70. [PMID: 25359503 DOI: 10.1007/s11120-014-0050-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 10/18/2014] [Indexed: 05/03/2023]
Abstract
Oxygenic photosynthesis in cyanobacteria, algae, and plants is carried out by a fabulous pigment-protein machinery that is amazingly complicated in structure and function. Many different approaches have been undertaken to characterize the most important aspects of photosynthesis, and proteomics has become the essential component in this research. Here we describe various methods which have been used in proteomic research of cyanobacteria, and demonstrate how proteomics is implemented into on-going studies of photosynthesis in cyanobacterial cells.
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Affiliation(s)
- Natalia Battchikova
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turku, Finland.
| | - Martina Angeleri
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turku, Finland
| | - Eva-Mari Aro
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turku, Finland
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221
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γ-Lindane Increases Microcystin Synthesis in Microcystis aeruginosa PCC7806. Mar Drugs 2015; 13:5666-80. [PMID: 26404326 PMCID: PMC4584347 DOI: 10.3390/md13095666] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 07/20/2015] [Accepted: 07/29/2015] [Indexed: 11/17/2022] Open
Abstract
HCH factories, and the waste dumpsites associated to its production, have become a global environmental concern, and their runoff could pollute ground and surface waters with high levels of the pollutant. In this study, the influence of lindane (γ-HCH) on microcystin production has been investigated in Microcystis aeruginosa PCC7806. This toxic cyanobacterium is highly tolerant to γ-lindane (20 mg/L), and produces more toxin (microcystin) in the presence of the pollutant. Microcystis degrades γ-lindane and presence of γ-lindane induces genes involved in its own degradation (nirA). RT-PCRsq has been used to monitor changes in levels of transcripts encoded by the mcy operon (mcyD, mcyH and mcyJ), responsible for the microcystin synthesis machinery, as well as other genes involved in its transcriptional regulation, such as ntcA and fur family members. The presence of lindane in the culture media induces mcyD expression, as well as ntcA gene transcription, while other genes, such as mcyH, (putative ABC transporter), are downregulated. The amount of microcystin found in the cells and the culture media is higher when M. aeruginosa is treated with γ-lindane than in control cells. The results suggest that in a lindane polluted environment, Microcystis toxic strains may enhance their microcystin synthesis.
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222
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Alexova R, Dang TC, Fujii M, Raftery MJ, Waite TD, Ferrari BC, Neilan BA. Specific global responses to N and Fe nutrition in toxic and non-toxicMicrocystis aeruginosa. Environ Microbiol 2015; 18:401-13. [DOI: 10.1111/1462-2920.12958] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 06/05/2015] [Accepted: 06/15/2015] [Indexed: 01/03/2023]
Affiliation(s)
- Ralitza Alexova
- School of Biotechnology and Biomolecular Sciences; University of New South Wales; Sydney NSW 2052 Australia
| | - The Cuong Dang
- School of Civil and Environmental Engineering; University of New South Wales; Sydney NSW 2052 Australia
| | - Manabu Fujii
- School of Civil and Environmental Engineering; University of New South Wales; Sydney NSW 2052 Australia
- Department of Civil Engineering; Tokyo Institute of Technology; 2-12-1-M1-4 Ookayama Tokyo 152-8552 Japan
| | - Mark J. Raftery
- Bioanalytical Mass Spectrometry Facility; University of New South Wales; Sydney NSW 2052 Australia
| | - T. David Waite
- School of Civil and Environmental Engineering; University of New South Wales; Sydney NSW 2052 Australia
| | - Belinda C. Ferrari
- School of Biotechnology and Biomolecular Sciences; University of New South Wales; Sydney NSW 2052 Australia
- Australian Centre for Astrobiology; University of New South Wales; Sydney NSW 2052 Australia
| | - Brett A. Neilan
- School of Biotechnology and Biomolecular Sciences; University of New South Wales; Sydney NSW 2052 Australia
- Australian Centre for Astrobiology; University of New South Wales; Sydney NSW 2052 Australia
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223
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Kaplan A, Weiss G, Sukenik A. Cyanobacterial secondary metabolites mediate interspecies-intraspecies communication in the water body. Environ Microbiol 2015. [DOI: 10.1111/1462-2920.12922] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Aaron Kaplan
- Department of Plant and Environmental Sciences; The Hebrew University of Jerusalem; Edmond J. Safra Campus, Givat Ram Jerusalem 9190401 Israel
| | - Gad Weiss
- Department of Plant and Environmental Sciences; The Hebrew University of Jerusalem; Edmond J. Safra Campus, Givat Ram Jerusalem 9190401 Israel
| | - Assaf Sukenik
- The Yigal Allon Kinneret Limnological Laboratory; Israel Oceanographic and Limnological Research; P.O.B. 447 Migdal 14950 Israel
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224
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Briand E, Bormans M, Gugger M, Dorrestein PC, Gerwick WH. Changes in secondary metabolic profiles of Microcystis aeruginosa strains in response to intraspecific interactions. Environ Microbiol 2015; 18:384-400. [PMID: 25980449 DOI: 10.1111/1462-2920.12904] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 05/06/2015] [Accepted: 05/12/2015] [Indexed: 11/28/2022]
Abstract
The cyanobacteria Microcystis proliferate in freshwater ecosystems and produce bioactive compounds including the harmful toxins microcystins (MC). These secondary metabolites play an important role in shaping community composition through biotic interactions although their role and mode of regulation are poorly understood. As natural cyanobacterial populations include producing and non-producing strains, we tested if the production of a range of peptides by coexisting cells could be regulated through intraspecific interactions. With an innovative co-culturing chamber together with advanced mass spectrometry (MS) techniques, we monitored the growth and compared the metabolic profiles of a MC-producing as well as two non-MC-producing Microcystis strains under mono- and co-culture conditions. In monocultures, these strains grew comparably; however, the non-MC-producing mutant produced higher concentrations of cyanopeptolins, aerucyclamides and aeruginosins than the wild type. Physiological responses to co-culturing were reflected in a quantitative change in the production of the major peptides. Using a MS/MS-based molecular networking approach, we identified new analogues of known classes of peptides as well as new compounds. This work provides new insights into the factors that regulate the production of MC and other secondary metabolites in cyanobacteria, and suggests interchangeable or complementary functions allowing bloom-forming cyanobacteria to efficiently colonize and dominate in fluctuating aquatic environments.
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Affiliation(s)
- Enora Briand
- UMR CNRS 6553 ECOBIO, University of Rennes 1, 35042, Rennes Cedex, France.,Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093, USA
| | - Myriam Bormans
- UMR CNRS 6553 ECOBIO, University of Rennes 1, 35042, Rennes Cedex, France
| | - Muriel Gugger
- Collection of Cyanobacteria, Institut Pasteur, 75724, Paris, France
| | - Pieter C Dorrestein
- Collaborative Mass Spectrometry Innovation Center, University of California San Diego, La Jolla, CA, 92093, USA.,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - William H Gerwick
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093, USA.,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, 92093, USA
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225
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Brutemark A, Vandelannoote A, Engström-Öst J, Suikkanen S. A less saline Baltic Sea promotes cyanobacterial growth, hampers intracellular microcystin production, and leads to strain-specific differences in allelopathy. PLoS One 2015; 10:e0128904. [PMID: 26042598 PMCID: PMC4456099 DOI: 10.1371/journal.pone.0128904] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 05/03/2015] [Indexed: 11/19/2022] Open
Abstract
Salinity is one of the main factors that explain the distribution of species in the Baltic Sea. Increased precipitation and consequent increase in freshwater inflow is predicted to decrease salinity in some areas of the Baltic Sea. Clearly such changes may have profound effects on the organisms living there. Here we investigate the response of the commonly occurring cyanobacterium Dolichospermum spp. to three salinities, 0, 3 and 6. For the three strains tested we recorded growth, intracellular toxicity (microcystin) and allelopathic properties. We show that Dolichospermum can grow in all the three salinities tested with highest growth rates in the lowest salinity. All strains showed allelopathic potential and it differed significantly between strains and salinities, but was highest in the intermediate salinity and lowest in freshwater. Intracellular toxin concentration was highest in salinity 6. In addition, based on monitoring data from the northern Baltic Proper and the Gulf of Finland, we show that salinity has decreased, while Dolichospermum spp. biomass has increased between 1979 and 2013. Thus, based on our experimental findings it is evident that salinity plays a large role in Dolichospermum growth, allelopathic properties and toxicity. In combination with our long-term data analyses, we conclude that decreasing salinity is likely to result in a more favourable environment for Dolichospermum spp. in some areas of the Baltic Sea.
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Affiliation(s)
- Andreas Brutemark
- ARONIA Coastal Zone Research Team, Novia University of Applied Sciences & Åbo Akademi University, Ekenäs, Finland
- Tvärminne Zoological Station, University of Helsinki, Hanko, Finland
| | | | - Jonna Engström-Öst
- ARONIA Coastal Zone Research Team, Novia University of Applied Sciences & Åbo Akademi University, Ekenäs, Finland
- Tvärminne Zoological Station, University of Helsinki, Hanko, Finland
| | - Sanna Suikkanen
- Marine Research Centre, Finnish Environment Institute SYKE, Helsinki, Finland
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Beversdorf LJ, Miller TR, McMahon KD. Long-term monitoring reveals carbon-nitrogen metabolism key to microcystin production in eutrophic lakes. Front Microbiol 2015; 6:456. [PMID: 26029192 PMCID: PMC4428211 DOI: 10.3389/fmicb.2015.00456] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/27/2015] [Indexed: 02/04/2023] Open
Abstract
The environmental drivers contributing to cyanobacterial dominance in aquatic systems have been extensively studied. However, understanding of toxic vs. non-toxic cyanobacterial population dynamics and the mechanisms regulating cyanotoxin production remain elusive, both physiologically and ecologically. One reason is the disconnect between laboratory and field-based studies. Here, we combined 3 years of temporal data, including microcystin (MC) concentrations, 16 years of long-term ecological research, and 10 years of molecular data to investigate the potential factors leading to the selection of toxic Microcystis and MC production. Our analysis revealed that nitrogen (N) speciation and inorganic carbon (C) availability might be important drivers of Microcystis population dynamics and that an imbalance in cellular C: N ratios may trigger MC production. More specifically, precipitous declines in ammonium concentrations lead to a transitional period of N stress, even in the presence of high nitrate concentrations, that we call the “toxic phase.” Following the toxic phase, temperature and cyanobacterial abundance remained elevated but MC concentrations drastically declined. Increases in ammonium due to lake turnover may have led to down regulation of MC synthesis or a shift in the community from toxic to non-toxic species. While total phosphorus (P) to total N ratios were relatively low over the time-series, MC concentrations were highest when total N to total P ratios were also highest. Similarly, high C: N ratios were also strongly correlated to the toxic phase. We propose a metabolic model that corroborates molecular studies and reflects our ecological observations that C and N metabolism may regulate MC production physiologically and ecologically. In particular, we hypothesize that an imbalance between 2-oxoglutarate and ammonium in the cell regulates MC synthesis in the environment.
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Affiliation(s)
- Lucas J Beversdorf
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison Madison, WI, USA ; Joseph J. Zilber School of Public Health, University of Wisconsin-Milwaukee Milwaukee, WI, USA
| | - Todd R Miller
- Joseph J. Zilber School of Public Health, University of Wisconsin-Milwaukee Milwaukee, WI, USA
| | - Katherine D McMahon
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison Madison, WI, USA ; Department of Bacteriology, University of Wisconsin-Madison Madison, WI, USA
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227
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Beversdorf LJ, Chaston SD, Miller TR, McMahon KD. Microcystin mcyA and mcyE Gene Abundances Are Not Appropriate Indicators of Microcystin Concentrations in Lakes. PLoS One 2015; 10:e0125353. [PMID: 25945933 PMCID: PMC4422731 DOI: 10.1371/journal.pone.0125353] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 03/11/2015] [Indexed: 11/19/2022] Open
Abstract
Cyanobacterial harmful algal blooms (cyanoHABs) are a primary source of water quality degradation in eutrophic lakes. The occurrence of cyanoHABs is ubiquitous and expected to increase with current climate and land use change scenarios. However, it is currently unknown what environmental parameters are important for indicating the presence of cyanoHAB toxins making them difficult to predict or even monitor on time-scales relevant to protecting public health. Using qPCR, we aimed to quantify genes within the microcystin operon (mcy) to determine which cyanobacterial taxa, and what percentage of the total cyanobacterial community, were responsible for microcystin production in four eutrophic lakes. We targeted Microcystis-16S, mcyA, and Microcystis, Planktothrix, and Anabaena-specific mcyE genes. We also measured microcystins and several biological, chemical, and physical parameters--such as temperature, lake stability, nutrients, pigments and cyanobacterial community composition (CCC)--to search for possible correlations to gene copy abundance and MC production. All four lakes contained Microcystis-mcyE genes and high percentages of toxic Microcystis, suggesting Microcystis was the dominant microcystin producer. However, all genes were highly variable temporally, and in few cases, correlated with increased temperature and nutrients as the summer progressed. Interestingly, toxin gene abundances (and biomass indicators) were anti-correlated with microcystin in all lakes except the largest lake, Lake Mendota. Similarly, gene abundance and microcystins differentially correlated to CCC in all lakes. Thus, we conclude that the presence of microcystin genes are not a useful tool for eliciting an ecological role for toxins in the environment, nor are microcystin genes (e.g. DNA) a good indicator of toxins in the environment.
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Affiliation(s)
- Lucas J. Beversdorf
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin, 53706, United States of America
| | - Sheena D. Chaston
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, Wisconsin, 53706, United States of America
| | - Todd R. Miller
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, Wisconsin, 53706, United States of America
| | - Katherine D. McMahon
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin, 53706, United States of America
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, Wisconsin, 53706, United States of America
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228
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Binh CTT, Peterson CG, Tong T, Gray KA, Gaillard JF, Kelly JJ. Comparing Acute Effects of a Nano-TiO2 Pigment on Cosmopolitan Freshwater Phototrophic Microbes Using High-Throughput Screening. PLoS One 2015; 10:e0125613. [PMID: 25923116 PMCID: PMC4414569 DOI: 10.1371/journal.pone.0125613] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 03/24/2015] [Indexed: 01/16/2023] Open
Abstract
Production of titanium-dioxide nanomaterials (nano-TiO2) is increasing, leading to potential risks associated with unintended release of these materials into aquatic ecosystems. We investigated the acute effects of nano-TiO2 on metabolic activity and viability of algae and cyanobacteria using high-throughput screening. The responses of three diatoms (Surirella angusta, Cocconeis placentula, Achnanthidium lanceolatum), one green alga (Scenedesmus quadricauda), and three cyanobacteria (Microcystis aeruginosa, Gloeocapsa sp., Synechococcus cedrorum) to short-term exposure (15 to 60 min) to a common nano-TiO2 pigment (PW6; average crystallite size 81.5 nm) with simulated solar illumination were assessed. Five concentrations of nano-TiO2 (0.5, 2.5, 5, 10, and 25 mg L-1) were tested and a fluorescent reporter (fluorescein diacetate) was used to assess metabolic activity. Algae were sensitive to nano-TiO2, with all showing decreased metabolic activity after 30-min exposure to the lowest tested concentration. Microscopic observation of algae revealed increased abundance of dead cells with nano-TiO2 exposure. Cyanobacteria were less sensitive to nano-TiO2 than algae, with Gloeocapsa showing no significant decrease in activity with nano-TiO2 exposure and Synechococcus showing an increase in activity. These results suggest that nanomaterial contamination has the potential to alter the distribution of phototrophic microbial taxa within freshwater ecosystems. The higher resistance of cyanobacteria could have significant implications as cyanobacteria represent a less nutritious food source for higher trophic levels and some cyanobacteria can produce toxins and contribute to harmful algal blooms.
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Affiliation(s)
- Chu Thi Thanh Binh
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Christopher G. Peterson
- Institute of Environmental Sustainability, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Tiezheng Tong
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois, United States of America
| | - Kimberly A. Gray
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois, United States of America
| | - Jean-François Gaillard
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois, United States of America
| | - John J. Kelly
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
- * E-mail:
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229
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Mikkola R, Andersson MA, Hautaniemi M, Salkinoja-Salonen MS. Toxic indole alkaloids avrainvillamide and stephacidin B produced by a biocide tolerant indoor mold Aspergillus westerdijkiae. Toxicon 2015; 99:58-67. [PMID: 25804991 DOI: 10.1016/j.toxicon.2015.03.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 02/15/2015] [Accepted: 03/19/2015] [Indexed: 10/23/2022]
Abstract
Toxic Aspergillus westerdijkiae were present in house dust and indoor air fall-out from a residence and a kindergarten where the occupants suffered from building related ill health. The A. westerdijkiae isolates produced indole alkaloids avrainvillamide (445 Da) and its dimer stephacidin B (890 Da). It grew and sporulated in presence of high concentrations of boron or polyguanidine (PHMB, PHMG) based antimicrobial biocides used to remediate mold infested buildings. The boar sperm cells were used as sensor cells to purify toxins from HPLC fractions of the fungal biomass. Submicromolar concentrations (EC50 0.3-0.4 μM) blocked boar spermatozoan motility and killed porcine kidney tubular epithelial cells (PK-15). Plate grown hyphal mass of the A. westerdijkiae isolates contained 300-750 ng of avrainvillamide and 30-300 ng of stephacidin B per mg (wet weight). The toxins induced rapid (30 min) loss of boar sperm motility, followed (24 h) by loss of mitochondrial membrane potential (ΔΨm). Apoptotic cell death was observed in PK-15 cell monolayers, prior to cessation of glucose uptake or loss of ΔΨm. Avrainvillamide and stephacidin B were 100-fold more potent towards the porcine cells than the mycotoxins stephacidin A, ochratoxin A, sterigmatocystin and citrinin. The high toxicity of stephacidin B indicates a role of nitrone group in the mechanism of toxicity. Avrainvillamide and stephacidin B represent a new class of toxins with possible a threat to human health in buildings. Furthermore, the use of biocides highly enhanced the growth of toxigenic A. westerdijkiae.
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Affiliation(s)
- Raimo Mikkola
- Dept of Food and Environmental Science, POB56, University of Helsinki, FI-00014 Finland.
| | - Maria A Andersson
- Dept of Food and Environmental Science, POB56, University of Helsinki, FI-00014 Finland
| | - Maria Hautaniemi
- Finnish Food Safety Authority (EVIRA), Mustialankatu 3, FI000790 Helsinki, Finland
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230
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Rogers S, Puddick J, Wood SA, Dietrich DR, Hamilton DP, Prinsep MR. The effect of cyanobacterial biomass enrichment by centrifugation and GF/C filtration on subsequent microcystin measurement. Toxins (Basel) 2015; 7:821-34. [PMID: 25763766 PMCID: PMC4379527 DOI: 10.3390/toxins7030821] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Revised: 02/10/2015] [Accepted: 03/02/2015] [Indexed: 11/26/2022] Open
Abstract
Microcystins are cyclic peptides produced by multiple cyanobacterial genera. After accumulation in the liver of animals they inhibit eukaryotic serine/threonine protein phosphatases, causing liver disease or death. Accurate detection/quantification of microcystins is essential to ensure safe water resources and to enable research on this toxin. Previous methodological comparisons have focused on detection and extraction techniques, but have not investigated the commonly used biomass enrichment steps. These enrichment steps could modulate toxin production as recent studies have demonstrated that high cyanobacterial cell densities cause increased microcystin levels. In this study, three microcystin-producing strains were processed using no cell enrichment steps (by direct freezing at three temperatures) and with biomass enrichment (by centrifugation or GF/C filtration). After extraction, microcystins were analyzed using liquid chromatography-tandem mass spectrometry. All processing methods tested, except GF/C filtration, resulted in comparable microcystin quotas for all strains. The low yields observed for the filtration samples were caused by adsorption of arginine-containing microcystins to the GF/C filters. Whilst biomass enrichment did not affect microcystin metabolism over the time-frame of normal sample processing, problems associated with GF/C filtration were identified. The most widely applicable processing method was direct freezing of samples as it could be utilized in both field and laboratory environments.
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Affiliation(s)
- Shelley Rogers
- Department of Chemistry, School of Science, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand.
- Environmental Research Institute, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand.
| | | | - Susanna A Wood
- Environmental Research Institute, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand.
- Cawthron Institute, Private Bag 2, Nelson 7010, New Zealand.
| | - Daniel R Dietrich
- Human and Environmental Toxicology, University of Konstanz, P.O. Box 662, 78457 Konstanz, Germany.
| | - David P Hamilton
- Environmental Research Institute, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand.
| | - Michele R Prinsep
- Department of Chemistry, School of Science, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand.
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231
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Kopf M, Möke F, Bauwe H, Hess WR, Hagemann M. Expression profiling of the bloom-forming cyanobacterium Nodularia CCY9414 under light and oxidative stress conditions. ISME JOURNAL 2015; 9:2139-52. [PMID: 25689027 DOI: 10.1038/ismej.2015.16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 01/08/2015] [Indexed: 11/10/2022]
Abstract
Massive blooms of toxic cyanobacteria frequently occur in the central Baltic Sea during the summer. In the surface scum, cyanobacterial cells are exposed to high light (HL) intensity, high oxygen partial pressure and other stresses. To mimic these conditions, cultures of Nodularia spumigena CCY9414, which is a strain isolated from a cyanobacterial summer bloom in the Baltic Sea, were incubated at a HL intensity of 1200 μmol photons m(-2) s(-1) or a combination of HL and increased oxygen partial pressure. Using differential RNA sequencing, we compared the global primary transcriptomes of control and stressed cells. The combination of oxidative and light stresses induced the expression of twofold more genes compared with HL stress alone. In addition to the induction of known stress-responsive genes, such as psbA, ocp and sodB, Nodularia cells activated the expression of genes coding for many previously unknown light- and oxidative stress-related proteins. In addition, the expression of non-protein-coding RNAs was found to be stimulated by these stresses. Among them was an antisense RNA to the phycocyanin-encoding mRNA cpcBAC and the trans-encoded regulator of photosystem I, PsrR1. The large genome capacity allowed Nodularia to harbor more copies of stress-relevant genes such as psbA and small chlorophyll-binding protein genes, combined with the coordinated induction of these and many additional genes for stress acclimation. Our data provide a first insight on how N. spumigena became adapted to conditions relevant for a cyanobacterial bloom in the Baltic Sea.
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Affiliation(s)
- Matthias Kopf
- Albert-Ludwigs-Universität Freiburg, Fakultät für Biologie, Genetik und Experimentelle Bioinformatik, Freiburg, Germany
| | - Fred Möke
- Universität Rostock, Institut für Biowissenschaften, Pflanzenphysiologie, Rostock, Germany
| | - Hermann Bauwe
- Universität Rostock, Institut für Biowissenschaften, Pflanzenphysiologie, Rostock, Germany
| | - Wolfgang R Hess
- Albert-Ludwigs-Universität Freiburg, Fakultät für Biologie, Genetik und Experimentelle Bioinformatik, Freiburg, Germany
| | - Martin Hagemann
- Universität Rostock, Institut für Biowissenschaften, Pflanzenphysiologie, Rostock, Germany
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232
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Burnap RL, Hagemann M, Kaplan A. Regulation of CO2 Concentrating Mechanism in Cyanobacteria. Life (Basel) 2015; 5:348-71. [PMID: 25636131 PMCID: PMC4390856 DOI: 10.3390/life5010348] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 01/15/2015] [Accepted: 01/21/2015] [Indexed: 12/31/2022] Open
Abstract
In this chapter, we mainly focus on the acclimation of cyanobacteria to the changing ambient CO2 and discuss mechanisms of inorganic carbon (Ci) uptake, photorespiration, and the regulation among the metabolic fluxes involved in photoautotrophic, photomixotrophic and heterotrophic growth. The structural components for several of the transport and uptake mechanisms are described and the progress towards elucidating their regulation is discussed in the context of studies, which have documented metabolomic changes in response to changes in Ci availability. Genes for several of the transport and uptake mechanisms are regulated by transcriptional regulators that are in the LysR-transcriptional regulator family and are known to act in concert with small molecule effectors, which appear to be well-known metabolites. Signals that trigger changes in gene expression and enzyme activity correspond to specific "regulatory metabolites" whose concentrations depend on the ambient Ci availability. Finally, emerging evidence for an additional layer of regulatory complexity involving small non-coding RNAs is discussed.
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Affiliation(s)
- Robert L Burnap
- Department of Microbiology and Molecular Genetics, Henry Bellmon Research Center, Oklahoma State University, Stillwater, OK 74078, USA.
| | - Martin Hagemann
- Institute Biosciences, Department Plant Physiology, University of Rostock, Albert-Einstein-Straße 3, Rostock D-18059, Germany.
| | - Aaron Kaplan
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, Edmond J. Safra Campus, Givat Ram, Hebrew University of Jerusalem, Jerusalem 91904, Israel.
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233
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Tran CTD, Bernard C, Comte K. Cloning of some heat shock proteins genes for further transcriptional study of Planktothrix agardhii exposed to abiotic stress. Folia Microbiol (Praha) 2014; 60:317-23. [DOI: 10.1007/s12223-014-0372-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Accepted: 12/15/2014] [Indexed: 11/30/2022]
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234
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Schmidt JR, Wilhelm SW, Boyer GL. The fate of microcystins in the environment and challenges for monitoring. Toxins (Basel) 2014; 6:3354-87. [PMID: 25514094 PMCID: PMC4280539 DOI: 10.3390/toxins6123354] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 11/29/2014] [Accepted: 12/05/2014] [Indexed: 02/03/2023] Open
Abstract
Microcystins are secondary metabolites produced by cyanobacteria that act as hepatotoxins in higher organisms. These toxins can be altered through abiotic processes, such as photodegradation and adsorption, as well as through biological processes via metabolism and bacterial degradation. Some species of bacteria can degrade microcystins, and many other organisms metabolize microcystins into a series of conjugated products. There are toxicokinetic models used to examine microcystin uptake and elimination, which can be difficult to compare due to differences in compartmentalization and speciation. Metabolites of microcystins are formed as a detoxification mechanism, and little is known about how quickly these metabolites are formed. In summary, microcystins can undergo abiotic and biotic processes that alter the toxicity and structure of the microcystin molecule. The environmental impact and toxicity of these alterations and the metabolism of microcystins remains uncertain, making it difficult to establish guidelines for human health. Here, we present the current state of knowledge regarding the alterations microcystins can undergo in the environment.
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Affiliation(s)
- Justine R Schmidt
- Department of Chemistry, College of Environmental Science and Forestry, State University of New York, Syracuse, NY 13210, USA.
| | - Steven W Wilhelm
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996-0845, USA.
| | - Gregory L Boyer
- Department of Chemistry, College of Environmental Science and Forestry, State University of New York, Syracuse, NY 13210, USA.
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235
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Transcriptomics-aided dissection of the intracellular and extracellular roles of microcystin in Microcystis aeruginosa PCC 7806. Appl Environ Microbiol 2014; 81:544-54. [PMID: 25381232 DOI: 10.1128/aem.02601-14] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recent studies have provided evidence for both intracellular and extracellular roles of the potent hepatotoxin microcystin (MC) in the bloom-forming cyanobacterium Microcystis. Here, we surveyed transcriptomes of the wild-type strain M. aeruginosa PCC 7806 and the microcystin-deficient ΔmcyB mutant under low light conditions with and without the addition of external MC of the LR variant (MC-LR). Transcriptomic data acquired by microarray and quantitative PCR revealed substantial differences in the relative expression of genes of the central intermediary metabolism, photosynthesis, and energy metabolism. In particular, the data provide evidence for a lower photosystem I (PSI)-to-photosystem II (PSII) ratio and a more pronounced carbon limitation in the microcystin-deficient mutant. Interestingly, only 6% of the transcriptional differences could be complemented by external microcystin-LR addition. This MC signaling effect was seen exclusively for genes of the secondary metabolism category. The orphan polyketide synthase gene cluster IPF38-51 was specifically downregulated in response to external MC-LR under low light. Our data suggest a hierarchical and light-dependent cross talk of secondary metabolites and support both an intracellular and an extracellular role of MC in Microcystis.
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236
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Comparison of two ELISA-based methods for the detection of microcystins in blood serum. Chem Biol Interact 2014; 223:10-7. [DOI: 10.1016/j.cbi.2014.08.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 08/26/2014] [Accepted: 08/29/2014] [Indexed: 11/24/2022]
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237
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Yang Z, Kong F, Shi X, Yu Y, Zhang M. Effects of UV-B radiation on microcystin production of a toxic strain of Microcystis aeruginosa and its competitiveness against a non-toxic strain. JOURNAL OF HAZARDOUS MATERIALS 2014; 283:447-453. [PMID: 25464282 DOI: 10.1016/j.jhazmat.2014.09.053] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Revised: 09/02/2014] [Accepted: 09/25/2014] [Indexed: 06/04/2023]
Abstract
Microcystins (MCs) produced by toxic cyanobacteria pose a health hazard to humans and animals. Some environmental factors can alter the MC concentrations by affecting the abundance of toxin-producing strains in a cyanobacteria population and/or their toxin production. In this study, we designed a monoculture and competition experiment to investigate the impacts of UV-B radiation on MC production and the competition between toxin and non-toxin producing strains of Microcystis aeruginosa. UV-B radiation resulted in higher inhibition of the growth and photosynthetic activity of the non-toxin producing strain relative to that observed for the toxin-producing strain. Both intracellular and extracellular MC contents decreased markedly when the toxin-producing strain was exposed to UV-B radiation. In addition, a quantitative real-time PCR assay revealed that the ratio of toxin-producing M. aeruginosa under UV-B exposure was higher than that under PAR alone at an early stage of the experiment. However, its abundance under UV-B exposure was lower compared with the PAR alone treatment after day 12. Our study demonstrated that UV-B radiation has a great impact on the abundance of the toxin-producing strain in the Microcystis population and their toxin production, which suggests that the fluctuation of UV-B radiation affects the MC level of cyanobacteria blooms.
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Affiliation(s)
- Zhen Yang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China.
| | - Fanxiang Kong
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China.
| | - Xiaoli Shi
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China
| | - Yang Yu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China
| | - Min Zhang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China
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238
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Penn K, Wang J, Fernando SC, Thompson JR. Secondary metabolite gene expression and interplay of bacterial functions in a tropical freshwater cyanobacterial bloom. THE ISME JOURNAL 2014; 8:1866-78. [PMID: 24646695 PMCID: PMC4139720 DOI: 10.1038/ismej.2014.27] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 01/08/2014] [Accepted: 01/17/2014] [Indexed: 11/09/2022]
Abstract
Cyanobacterial harmful algal blooms (cyanoHABs) appear to be increasing in frequency on a global scale. The Cyanobacteria in blooms can produce toxic secondary metabolites that make freshwater dangerous for drinking and recreation. To characterize microbial activities in a cyanoHAB, transcripts from a eutrophic freshwater reservoir in Singapore were sequenced for six samples collected over one day-night period. Transcripts from the Cyanobacterium Microcystis dominated all samples and were accompanied by at least 533 genera primarily from the Cyanobacteria, Proteobacteria, Bacteroidetes and Actinobacteria. Within the Microcystis population, abundant transcripts were from genes for buoyancy, photosynthesis and synthesis of the toxin microviridin, suggesting that these are necessary for competitive dominance in the Reservoir. During the day, Microcystis transcripts were enriched in photosynthesis and energy metabolism while at night enriched pathways included DNA replication and repair and toxin biosynthesis. Microcystis was the dominant source of transcripts from polyketide and non-ribosomal peptide synthase (PKS and NRPS, respectively) gene clusters. Unexpectedly, expression of all PKS/NRPS gene clusters, including for the toxins microcystin and aeruginosin, occurred throughout the day-night cycle. The most highly expressed PKS/NRPS gene cluster from Microcystis is not associated with any known product. The four most abundant phyla in the reservoir were enriched in different functions, including photosynthesis (Cyanobacteria), breakdown of complex organic molecules (Proteobacteria), glycan metabolism (Bacteroidetes) and breakdown of plant carbohydrates, such as cellobiose (Actinobacteria). These results provide the first estimate of secondary metabolite gene expression, functional partitioning and functional interplay in a freshwater cyanoHAB.
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Affiliation(s)
- Kevin Penn
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jia Wang
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Samodha C Fernando
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Janelle R Thompson
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
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239
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Hu C, Völler G, Süßmuth R, Dittmann E, Kehr JC. Functional assessment of mycosporine-like amino acids inMicrocystis aeruginosastrain PCC 7806. Environ Microbiol 2014; 17:1548-59. [DOI: 10.1111/1462-2920.12577] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 07/19/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Chenlin Hu
- Department of Microbiology; Institute for Biochemistry and Biology; University of Potsdam; Karl-Liebknecht-Str. 24/25 Potsdam-Golm 14476 Germany
| | - Ginka Völler
- Institut für Chemie; Technical University Berlin; Strasse des 17. Juni 124 Berlin 10623 Germany
| | - Roderich Süßmuth
- Institut für Chemie; Technical University Berlin; Strasse des 17. Juni 124 Berlin 10623 Germany
| | - Elke Dittmann
- Department of Microbiology; Institute for Biochemistry and Biology; University of Potsdam; Karl-Liebknecht-Str. 24/25 Potsdam-Golm 14476 Germany
| | - Jan-Christoph Kehr
- Department of Microbiology; Institute for Biochemistry and Biology; University of Potsdam; Karl-Liebknecht-Str. 24/25 Potsdam-Golm 14476 Germany
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240
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Meissner S, Steinhauser D, Dittmann E. Metabolomic analysis indicates a pivotal role of the hepatotoxin microcystin in high light adaptation ofMicrocystis. Environ Microbiol 2014; 17:1497-509. [DOI: 10.1111/1462-2920.12565] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 07/05/2014] [Indexed: 12/12/2022]
Affiliation(s)
- Sven Meissner
- Department of Microbiology; Institute for Biochemistry and Biology; University of Potsdam; Karl-Liebknecht-Str. 24/25 Potsdam-Golm 14476 Germany
| | - Dirk Steinhauser
- Max Planck Institute of Molecular Plant Physiology; Am Mühlenberg Potsdam-Golm 14476 Germany
| | - Elke Dittmann
- Department of Microbiology; Institute for Biochemistry and Biology; University of Potsdam; Karl-Liebknecht-Str. 24/25 Potsdam-Golm 14476 Germany
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241
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Microcystin production and regulation under nutrient stress conditions in toxic microcystis strains. Appl Environ Microbiol 2014; 80:5836-43. [PMID: 25038094 DOI: 10.1128/aem.01009-14] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microcystin is a common and well-known cyanobacterial toxin whose intracellular role is still under investigation. Increasing knowledge on microcystin gene expression and regulation can contribute to the understanding of its putative cellular function. In this work, reverse transcription-quantitative PCR (RT-qPCR) was used to investigate the transcriptional response of the mcyD gene to nitrogen (nitrate and ammonium) and phosphorus limitation in two toxic Microcystis strains. The existence of a direct correlation between transcripts of mcyD and ntcA genes was also identified. In previous studies, NtcA (global nitrogen regulator) has been described as a potential component in the control of microcystin biosynthesis. This research showed that stress agents linked to nutrient deprivation could lead to a significant increase of microcystin production in both strains studied. The more toxic strain proved to be more resistant to nutrient limitation. The similar outcomes of mcyD regulation observed for all nutrients suggest that this response can be linked to oxidative stress of cells undergoing adverse growth conditions.
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242
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Boopathi T, Ki JS. Impact of environmental factors on the regulation of cyanotoxin production. Toxins (Basel) 2014; 6:1951-78. [PMID: 24967641 PMCID: PMC4113735 DOI: 10.3390/toxins6071951] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 06/06/2014] [Accepted: 06/17/2014] [Indexed: 11/25/2022] Open
Abstract
Cyanobacteria are capable of thriving in almost all environments. Recent changes in climatic conditions due to increased human activities favor the occurrence and severity of harmful cyanobacterial bloom all over the world. Knowledge of the regulation of cyanotoxins by the various environmental factors is essential for effective management of toxic cyanobacterial bloom. In recent years, progress in the field of molecular mechanisms involved in cyanotoxin production has paved the way for assessing the role of various factors on the cyanotoxin production. In this review, we present an overview of the influence of various environmental factors on the production of major group of cyanotoxins, including microcystins, nodularin, cylindrospermopsin, anatoxins and saxitoxins.
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Affiliation(s)
| | - Jang-Seu Ki
- Department of Life Science, Sangmyung University, Seoul 110-743, Korea.
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243
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Survival, growth and toxicity of Microcystis aeruginosa PCC 7806 in experimental conditions mimicking some features of the human gastro-intestinal environment. Chem Biol Interact 2014; 215:54-61. [DOI: 10.1016/j.cbi.2014.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 01/21/2014] [Accepted: 03/15/2014] [Indexed: 01/06/2023]
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244
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Gehringer MM, Wannicke N. Climate change and regulation of hepatotoxin production in Cyanobacteria. FEMS Microbiol Ecol 2014; 88:1-25. [PMID: 24490596 DOI: 10.1111/1574-6941.12291] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 01/20/2014] [Accepted: 01/20/2014] [Indexed: 01/04/2023] Open
Abstract
Harmful, bloom-forming cyanobacteria (CyanoHABs) are occurring with increasing regularity in freshwater and marine ecosystems. The most commonly occurring cyanobacterial toxins are the hepatotoxic microcystin and nodularin. These cyclic hepta- and pentapeptides are synthesised nonribosomally by the gene products of the toxin gene clusters mcy and nda, respectively. Understanding of the regulation of hepatotoxin production is incomplete, although there is strong evidence supporting the roles of iron, light, higher nitrate availability and inorganic carbon in modulating microcystin levels. The majority of these studies have focused on the unicellular freshwater, microcystin-producing strain of Microcystis aeruginosa, with little attention being paid to terrestrial or marine toxin producers. This review intends to investigate the regulation of microcystin and nodularin production in unicellular and filamentous diazotrophic cyanobacteria against the background of changing climate conditions. Special focus is given to diazotrophic filamentous cyanobacteria, for example Nodularia spumigena, capable of regulating their nitrogen levels by actively fixing dinitrogen. By combining data from significant studies, an overall scheme of the regulation of toxin production is presented, focussing specifically on nodularin production in diazotrophs against the background of increasing carbon dioxide concentrations and temperatures envisaged under current climate change models. Furthermore, the risk of sustaining and spreading CyanoHABs in the future ocean is evaluated.
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Affiliation(s)
- Michelle M Gehringer
- Department of Plant Ecology and Systematics, Technical University of Kaiserslautern, Kaiserslautern, Germany
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245
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Sandrini G, Matthijs HCP, Verspagen JMH, Muyzer G, Huisman J. Genetic diversity of inorganic carbon uptake systems causes variation in CO2 response of the cyanobacterium Microcystis. THE ISME JOURNAL 2014; 8:589-600. [PMID: 24132080 PMCID: PMC3930318 DOI: 10.1038/ismej.2013.179] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 09/10/2013] [Accepted: 09/11/2013] [Indexed: 11/09/2022]
Abstract
Rising CO2 levels may act as an important selective factor on the CO2-concentrating mechanism (CCM) of cyanobacteria. We investigated genetic diversity in the CCM of Microcystis aeruginosa, a species producing harmful cyanobacterial blooms in many lakes worldwide. All 20 investigated Microcystis strains contained complete genes for two CO2 uptake systems, the ATP-dependent bicarbonate uptake system BCT1 and several carbonic anhydrases (CAs). However, 12 strains lacked either the high-flux bicarbonate transporter BicA or the high-affinity bicarbonate transporter SbtA. Both genes, bicA and sbtA, were located on the same operon, and the expression of this operon is most likely regulated by an additional LysR-type transcriptional regulator (CcmR2). Strains with only a small bicA fragment clustered together in the phylogenetic tree of sbtAB, and the bicA fragments were similar in strains isolated from different continents. This indicates that a common ancestor may first have lost most of its bicA gene and subsequently spread over the world. Growth experiments showed that strains with sbtA performed better at low inorganic carbon (Ci) conditions, whereas strains with bicA performed better at high Ci conditions. This offers an alternative explanation of previous competition experiments, as our results reveal that the competition at low CO2 levels was won by a specialist with only sbtA, whereas a generalist with both bicA and sbtA won at high CO2 levels. Hence, genetic and phenotypic variation in Ci uptake systems provide Microcystis with the potential for microevolutionary adaptation to changing CO2 conditions, with a selective advantage for bicA-containing strains in a high-CO2 world.
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Affiliation(s)
- Giovanni Sandrini
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Hans C P Matthijs
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Jolanda M H Verspagen
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Gerard Muyzer
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Jef Huisman
- Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands.
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246
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D'Agostino PM, Song X, Neilan BA, Moffitt MC. Comparative proteomics reveals that a saxitoxin-producing and a nontoxic strain of Anabaena circinalis are two different ecotypes. J Proteome Res 2014; 13:1474-84. [PMID: 24460188 DOI: 10.1021/pr401007k] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In Australia, saxitoxin production is restricted to the cyanobacterial species Anabaena circinalis and is strain-dependent. We aimed to characterize a saxitoxin-producing and nontoxic strain of A. circinalis at the proteomic level using iTRAQ. Seven proteins putatively involved in saxitoxin biosynthesis were identified within our iTRAQ experiment for the first time. The proteomic profile of the toxic A. circinalis was significantly different from the nontoxic strain, indicating that each is likely to inhabit a unique ecological niche. Under control growth conditions, the saxitoxin-producing A. circinalis displayed a higher abundance of photosynthetic, carbon fixation and nitrogen metabolic proteins. Differential abundance of these proteins suggests a higher intracellular C:N ratio and a higher concentration of intracellular 2-oxoglutarate in our toxic strain compared with the nontoxic strain. This may be a novel site for posttranslational regulation because saxitoxin biosynthesis putatively requires a 2-oxoglutarate-dependent dioxygenase. The nontoxic A. circinalis was more abundant in proteins, indicating cellular stress. Overall, our study has provided the first insight into fundamental differences between a toxic and nontoxic strain of A. circinalis, indicating that they are distinct ecotypes.
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Affiliation(s)
- Paul M D'Agostino
- School of Science and Health, University of Western Sydney , Campbelltown, NSW 2560, Australia
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247
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Kleinteich J, Wood SA, Puddick J, Schleheck D, Küpper FC, Dietrich D. Potent toxins in Arctic environments – Presence of saxitoxins and an unusual microcystin variant in Arctic freshwater ecosystems. Chem Biol Interact 2013; 206:423-31. [DOI: 10.1016/j.cbi.2013.04.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 04/04/2013] [Accepted: 04/11/2013] [Indexed: 10/26/2022]
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248
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249
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Sabart M, Misson B, Descroix A, Duffaud E, Combourieu B, Salençon MJ, Latour D. The importance of small colonies in sustaining Microcystis population exposed to mixing conditions: an exploration through colony size, genotypic composition and toxic potential. ENVIRONMENTAL MICROBIOLOGY REPORTS 2013; 5:747-756. [PMID: 24115626 DOI: 10.1111/1758-2229.12077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 06/13/2013] [Indexed: 06/02/2023]
Abstract
Microcystis is a toxic colony-forming cyanobacterium, which can bloom in a wide range of freshwater ecosystems. Despite the ecological advantage of the colonial form, few studies have paid attention to the size of Microcystis colonies in the field. With the aim of evaluating the impact of a fluctuating physical environment on the colony size, the genotypic composition and the toxic potential of a Microcystis population, we investigated five different colony size classes of a Microcystis bloom in the Grangent reservoir (France). By sequencing the internal transcribed spacer of the ribosomal operon, we evidenced changes in the genetic structure among size classes in response to environmental change. While similar genotypes were seen in every size class in stable conditions, new dominant genotypes appeared in the smallest colonies (< 160 μm) concomitantly with mixing conditions, strongly suggesting the importance of these colonies in response to disturbances. Moreover, these small colonies played a major role in microcystin production during this bloom, since very high microcystin contents (> 1 pg.cell.(-1)) were found in their cells. These findings indicate that the colony size distribution of a Microcystis population in response to disturbance could be an adaptive strategy that may explain its ecological success in freshwater ecosystems.
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Affiliation(s)
- Marion Sabart
- Clermont Université, Laboratoire Microorganismes: Génome et Environnement, Université Blaise Pascal, BP 10448, F-63000, Clermont Ferrand, France; UMR 6023, LMGE, CNRS, BP 80026, F-63171, Aubière Cedex, France
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250
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Catherine Q, Susanna W, Isidora ES, Mark H, Aurélie V, Jean-François H. A review of current knowledge on toxic benthic freshwater cyanobacteria--ecology, toxin production and risk management. WATER RESEARCH 2013; 47:5464-79. [PMID: 23891539 DOI: 10.1016/j.watres.2013.06.042] [Citation(s) in RCA: 202] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 06/19/2013] [Accepted: 06/21/2013] [Indexed: 05/12/2023]
Abstract
Benthic cyanobacteria are found globally in plethora of environments. Although they have received less attention than their planktonic freshwater counterparts, it is now well established that they produce toxins and reports of their involvement in animal poisonings have increased markedly during the last decade. Most of the known cyanotoxins have been identified from benthic cyanobacteria including: the hepatotoxic microcystins, nodularins and cylindrospermopsins, the neurotoxic saxitoxins, anatoxin-a and homoanatoxin-a and dermatotoxins, such as lyngbyatoxin. In most countries, observations of toxic benthic cyanobacteria are fragmented, descriptive and in response to animal toxicosis events. Only a limited number of long-term studies have aimed to understand why benthic proliferations occur, and/or how toxin production is regulated. These studies have shown that benthic cyanobacterial blooms are commonly a mixture of toxic and non-toxic genotypes and that toxin concentrations can be highly variable spatially and temporally. Physiochemical parameters responsible for benthic proliferation vary among habitat type with physical disturbance (e.g., flow regimes, wave action) and nutrients commonly identified as important. As climatic conditions change and anthropogenic pressures on waterways increase, it seems likely that the prevalence of blooms of benthic cyanobacteria will increase. In this article we review current knowledge on benthic cyanobacteria: ecology, toxin-producing species, variables that regulate toxin production and bloom formation, their impact on aquatic and terrestrial organisms and current monitoring and management strategies. We suggest research needs that will assist in filling knowledge gaps and ultimately allow more robust monitoring and management protocols to be developed.
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Affiliation(s)
- Quiblier Catherine
- MNHN, UMR 7245, 57 rue Cuvier, CP39, 75231 Paris Cedex 05, France; Université Paris Diderot, 5 rue T. Mann, 75013 Paris, France.
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