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Fernández-Valero AD, Karpov SA, Sampedro N, Gordi J, Timoneda N, Garcés E, Reñé A. Newly identified diversity of Dinomycetaceae (Rhizophydiales, Chytridiomycota), a family of fungal parasites of marine dinoflagellates. Eur J Protistol 2024; 93:126053. [PMID: 38350179 DOI: 10.1016/j.ejop.2024.126053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 01/22/2024] [Accepted: 01/23/2024] [Indexed: 02/15/2024]
Abstract
We identified two new parasite species of Chytridiomycota isolated during blooms of the dinoflagellate Alexandrium minutum in the coastal Mediterranean Sea. Light and electron microscopy together with molecular characterization of the nuclear 18S, ITS, and 28S rDNA regions led to their identification as two new species, Dinomyces gilberthii and Paradinomyces evelyniae, both belonging to the family Dinomycetaceae, order Rhizophydiales. Dinomyces gilberthii differs from the previously described D. arenysensis by the presence of discharge papillae and the development of a drop-shaped sporangium. Paradinomyces evelyniae differs from the previously described P. triforaminorum by the prominent lipid globule present in early sporangia and by the pointed end producing a rhizoid. The two chytrids differed in their geographical distribution. Dinomyces gilberthii was detected in several Mediterranean habitats, including harbours and beaches, and was particularly prevalent during summer dinoflagellate blooms. Its widespread occurrence in coastal ecosystems suggested a high level of adaptability to this environment. Paradinomyces evelyniae had a more restricted distribution in the coastal-marine environment, occurring in harbour sediments and only occasionally in the water column during winter and early spring. Paradinomyces evelyniae has previously been detected in the Baltic Sea, suggesting that its distribution encompasses contrasting coastal environments, although its presence is rare.
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Affiliation(s)
- Alan Denis Fernández-Valero
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (CSIC), Pg. Marítim de la Barceloneta, 37-49, 08003 Barcelona, Catalonia, Spain.
| | - Sergey A Karpov
- Department of Invertebrate Zoology, Biological Faculty, St Petersburg State University, Universitetskaya nab. 7/9, St Petersburg 199034, Russia; Zoological Institute of Russian Academy of Sciences, Universitetskaya nab. 1, St Petersburg 199034, Russia; North-Western State Medical University named after I.I. Mechnikov, Kirochnaya st. 41, St Petersburg 191015, Russia
| | - Nagore Sampedro
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (CSIC), Pg. Marítim de la Barceloneta, 37-49, 08003 Barcelona, Catalonia, Spain
| | - Jordina Gordi
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (CSIC), Pg. Marítim de la Barceloneta, 37-49, 08003 Barcelona, Catalonia, Spain
| | - Natàlia Timoneda
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (CSIC), Pg. Marítim de la Barceloneta, 37-49, 08003 Barcelona, Catalonia, Spain
| | - Esther Garcés
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (CSIC), Pg. Marítim de la Barceloneta, 37-49, 08003 Barcelona, Catalonia, Spain
| | - Albert Reñé
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (CSIC), Pg. Marítim de la Barceloneta, 37-49, 08003 Barcelona, Catalonia, Spain
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Abonyi A, Fornberg J, Rasconi S, Ptacnik R, Kainz MJ, Lafferty KD. The chytrid insurance hypothesis: integrating parasitic chytrids into a biodiversity-ecosystem functioning framework for phytoplankton-zooplankton population dynamics. Oecologia 2024; 204:279-288. [PMID: 38366067 PMCID: PMC10907492 DOI: 10.1007/s00442-024-05519-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 01/28/2024] [Indexed: 02/18/2024]
Abstract
In temperate lakes, eutrophication and warm temperatures can promote cyanobacteria blooms that reduce water quality and impair food-chain support. Although parasitic chytrids of phytoplankton might compete with zooplankton, they also indirectly support zooplankton populations through the "mycoloop", which helps move energy and essential dietary molecules from inedible phytoplankton to zooplankton. Here, we consider how the mycoloop might fit into the biodiversity-ecosystem functioning (BEF) framework. BEF considers how more diverse communities can benefit ecosystem functions like zooplankton production. Chytrids are themselves part of pelagic food webs and they directly contribute to zooplankton diets through spore production and by increasing host edibility. The additional way that chytrids might support BEF is if they engage in "kill-the-winner" dynamics. In contrast to grazers, which result in "eat-the-edible" dynamics, kill-the-winner dynamics can occur for host-specific infectious diseases that control the abundance of dominant (in this case inedible) hosts and thus limit the competitive exclusion of poorer (in this case edible) competitors. Thus, if phytoplankton diversity provides functions, and chytrids support algal diversity, chytrids could indirectly favour edible phytoplankton. All three mechanisms are linked to diversity and therefore provide some "insurance" for zooplankton production against the impacts of eutrophication and warming. In our perspective piece, we explore evidence for the chytrid insurance hypothesis, identify exceptions and knowledge gaps, and outline future research directions.
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Affiliation(s)
- András Abonyi
- WasserCluster Lunz-Biologische Station GmbH, Dr. Carl Kupelwieser Promenade 5, 3293, Lunz Am See, Austria.
- MTA-ÖK Lendület "Momentum" Fluvial Ecology Research Group, Institute of Aquatic Ecology, HUN-REN Centre for Ecological Research, Karolina Street 29, 1113, Budapest, Hungary.
| | - Johanna Fornberg
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Serena Rasconi
- Université Savoie Mont Blanc, INRAE, CARRTEL, 74200, Thonon-Les-Bains, France
| | - Robert Ptacnik
- WasserCluster Lunz-Biologische Station GmbH, Dr. Carl Kupelwieser Promenade 5, 3293, Lunz Am See, Austria
| | - Martin J Kainz
- WasserCluster Lunz-Biologische Station GmbH, Dr. Carl Kupelwieser Promenade 5, 3293, Lunz Am See, Austria
- Donau-Universität Krems, Dr. Karl Dorrek Straße 30, 3500, Krems, Austria
| | - Kevin D Lafferty
- U.S. Geological Survey, Western Ecological Research Center, at Marine Science Institute, UC Santa Barbara, Santa Barbara, CA, 93106-6150, USA
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Fuster M, Ruiz T, Lamarque A, Coulon M, Legrand B, Sabart M, Latour D, Mallet C. Cyanosphere Dynamic During Dolichospermum Bloom: Potential Roles in Cyanobacterial Proliferation. MICROBIAL ECOLOGY 2023; 87:3. [PMID: 38008821 DOI: 10.1007/s00248-023-02317-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 10/24/2023] [Indexed: 11/28/2023]
Abstract
Under the effect of global change, management of cyanobacterial proliferation becomes increasingly pressing. Given the importance of interactions within microbial communities in aquatic ecosystems, a handful of studies explored the potential relations between cyanobacteria and their associated bacterial community (i.e., cyanosphere). Yet, most of them specifically focused on the ubiquitous cyanobacteria Microcystis, overlooking other genera. Here, based on 16s rDNA metabarcoding analysis, we confirmed the presence of cyanosphere representing up to 30% of the total bacterial community diversity, during bloom episode of another preponderant cyanobacterial genus, Dolichospermum. Moreover, we highlighted a temporal dynamic of this cyanosphere. A sPLS-DA model permits to discriminate three important dates and 220 OTUs. With their affiliations, we were able to show how these variations potentially imply a turnover in ecological functions depending on bloom phases. Although more studies are necessary to quantify the impacts of these variations, we argue that cyanosphere can have an important, yet underestimated, role in the modulation of cyanobacterial blooms.
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Affiliation(s)
- Maxime Fuster
- Université Clermont Auvergne, CNRS, LMGE, F-63000, Clermont-Ferrand, France.
| | - Thomas Ruiz
- Université Clermont Auvergne, CNRS, LMGE, F-63000, Clermont-Ferrand, France
| | - Amélie Lamarque
- Université Clermont Auvergne, CNRS, LMGE, F-63000, Clermont-Ferrand, France
| | - Marianne Coulon
- Université Clermont Auvergne, CNRS, LMGE, F-63000, Clermont-Ferrand, France
| | | | - Marion Sabart
- Université Clermont Auvergne, CNRS, LMGE, F-63000, Clermont-Ferrand, France
| | - Delphine Latour
- Université Clermont Auvergne, CNRS, LMGE, F-63000, Clermont-Ferrand, France
| | - Clarisse Mallet
- Université Clermont Auvergne, CNRS, LMGE, F-63000, Clermont-Ferrand, France
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Fernández-Valero AD, Reñé A, Timoneda N, Pou-Solà N, Gordi J, Sampedro N, Garcés E. The succession of epiphytic microalgae conditions fungal community composition: how chytrids respond to blooms of dinoflagellates. ISME COMMUNICATIONS 2023; 3:103. [PMID: 37752353 PMCID: PMC10522651 DOI: 10.1038/s43705-023-00304-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 08/31/2023] [Accepted: 09/05/2023] [Indexed: 09/28/2023]
Abstract
This study aims to investigate the temporal dynamics of the epiphytic protist community on macroalgae, during the summer months, with a specific focus on fungi, and the interactions between zoosporic chytrid parasites and the proliferation of the dinoflagellates. We employed a combination of environmental sequencing techniques, incubation of natural samples, isolation of target organisms and laboratory experiments. Metabarcoding sequencing revealed changes in the dominant members of the epiphytic fungal community. Initially, fungi comprised < 1% of the protist community, mostly accounted for by Basidiomycota and Ascomycota, but with the emergence of Chytridiomycota during the mature phase of the biofilm, the fungal contribution increased to almost 30%. Chytridiomycota became dominant in parallel with an increase in the relative abundance of dinoflagellates in the community. Microscopy observations showed a general presence of chytrids following the peak proliferation of the dinoflagellate Ostreopsis sp., with the parasite, D. arenysensis as the dominant chytrid. The maximum infection prevalence was 2% indicating host-parasite coexistence. To further understand the in-situ prevalence of chytrids, we characterised the dynamics of the host abundance and prevalence of chytrids through co-culture. These laboratory experiments revealed intraspecific variability of D. arenysensis in its interaction with Ostreopsis, exhibiting a range from stable coexistence to the near-extinction of the host population. Moreover, while chytrids preferentially parasitized dinoflagellate cells, one of the strains examined displayed the ability to utilize pollen as a resource to maintain its viability, thus illustrating a facultative parasitic lifestyle. Our findings not only enrich our understanding of the diversity, ecology, and progression of epiphytic microalgal and fungal communities on Mediterranean coastal macroalgae, but they also shed light on the presence of zoosporic parasites in less-explored benthic habitats.
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Affiliation(s)
- Alan Denis Fernández-Valero
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (CSIC), Pg. Marítim de la Barceloneta, 37-49, 08003, Barcelona, Catalonia, Spain.
| | - Albert Reñé
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (CSIC), Pg. Marítim de la Barceloneta, 37-49, 08003, Barcelona, Catalonia, Spain
| | - Natàlia Timoneda
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (CSIC), Pg. Marítim de la Barceloneta, 37-49, 08003, Barcelona, Catalonia, Spain
| | - Núria Pou-Solà
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (CSIC), Pg. Marítim de la Barceloneta, 37-49, 08003, Barcelona, Catalonia, Spain
| | - Jordina Gordi
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (CSIC), Pg. Marítim de la Barceloneta, 37-49, 08003, Barcelona, Catalonia, Spain
| | - Nagore Sampedro
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (CSIC), Pg. Marítim de la Barceloneta, 37-49, 08003, Barcelona, Catalonia, Spain
| | - Esther Garcés
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (CSIC), Pg. Marítim de la Barceloneta, 37-49, 08003, Barcelona, Catalonia, Spain
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do Amaral SC, Xavier LP, Vasconcelos V, Santos AV. Cyanobacteria: A Promising Source of Antifungal Metabolites. Mar Drugs 2023; 21:359. [PMID: 37367684 DOI: 10.3390/md21060359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/23/2023] [Accepted: 05/27/2023] [Indexed: 06/28/2023] Open
Abstract
Cyanobacteria are a rich source of secondary metabolites, and they have received a great deal of attention due to their applicability in different industrial sectors. Some of these substances are known for their notorious ability to inhibit fungal growth. Such metabolites are very chemically and biologically diverse. They can belong to different chemical classes, including peptides, fatty acids, alkaloids, polyketides, and macrolides. Moreover, they can also target different cell components. Filamentous cyanobacteria have been the main source of these compounds. This review aims to identify the key features of these antifungal agents, as well as the sources from which they are obtained, their major targets, and the environmental factors involved when they are being produced. For the preparation of this work, a total of 642 documents dating from 1980 to 2022 were consulted, including patents, original research, review articles, and theses.
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Affiliation(s)
- Samuel Cavalcante do Amaral
- Laboratory of Biotechnology of Enzymes and Biotransformation, Biological Sciences Institute, Federal University of Pará, Belém 66075-110, Brazil
| | - Luciana Pereira Xavier
- Laboratory of Biotechnology of Enzymes and Biotransformation, Biological Sciences Institute, Federal University of Pará, Belém 66075-110, Brazil
| | - Vítor Vasconcelos
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, Terminal de Cruzeiros do Porto de Leixões, University of Porto, 4450-208 Matosinhos, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, Edifício FC4, 4169-007 Porto, Portugal
| | - Agenor Valadares Santos
- Laboratory of Biotechnology of Enzymes and Biotransformation, Biological Sciences Institute, Federal University of Pará, Belém 66075-110, Brazil
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Abonyi A, Rasconi S, Ptacnik R, Pilecky M, Kainz MJ. Chytrids enhance Daphnia fitness by selectively retained chytrid-synthesised stearidonic acid and conversion of short-chain to long-chain polyunsaturated fatty acids. FRESHWATER BIOLOGY 2023; 68:77-90. [PMID: 37064759 PMCID: PMC10099718 DOI: 10.1111/fwb.14010] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/11/2022] [Accepted: 10/13/2022] [Indexed: 06/09/2023]
Abstract
Chytrid fungal parasites convert dietary energy and essential dietary molecules, such as long-chain (LC) polyunsaturated fatty acids (PUFA), from inedible algal/cyanobacteria hosts into edible zoospores. How the improved biochemical PUFA composition of chytrid-infected diet may extend to zooplankton, linking diet quality to consumer fitness, remains unexplored.Here, we assessed the trophic role of chytrids in supporting dietary energy and PUFA requirements of the crustacean zooplankton Daphnia, when feeding on the filamentous cyanobacterium Planktothrix.Only Daphnia feeding on chytrid-infected Planktothrix reproduced successfully and had significantly higher survival and growth rates compared with Daphnia feeding on the sole Planktothrix diet. While the presence of chytrids resulted in a two-fold increase of carbon ingested by Daphnia, carbon assimilation increased by a factor of four, clearly indicating enhanced carbon transfer efficiency with chytrid presence.Bulk carbon (δ 13C) and nitrogen (δ 15N) stable isotopes did not indicate any treatment-specific dietary effects on Daphnia, nor differences in trophic position among diet sources and the consumer. Compound-specific carbon isotopes of fatty acids (δ 13CFA), however, revealed that chytrids bioconverted short-chain to LC-PUFA, making it available for Daphnia. Chytrids synthesised the ω-3 PUFA stearidonic acid de novo, which was selectively retained by Daphnia. Values of δ 13CFA demonstrated that Daphnia also bioconverted short-chain to LC-PUFA.We provide isotopic evidence that chytrids improved the dietary provision of LC-PUFA for Daphnia and enhanced their fitness. We argue for the existence of a positive feedback loop between enhanced Daphnia growth and herbivory in response to chytrid-mediated improved diet quality. Chytrids upgrade carbon from the primary producer and facilitate energy and PUFA transfer to primary consumers, potentially also benefitting upper trophic levels of pelagic food webs.
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Affiliation(s)
- András Abonyi
- WasserCluster Lunz – Biological StationLunz am SeeAustria
- Centre for Ecological ResearchInstitute of Aquatic EcologyBudapestHungary
| | - Serena Rasconi
- WasserCluster Lunz – Biological StationLunz am SeeAustria
- Université Savoie Mont Blanc, INRAE, CARRTELThonon‐les‐BainsFrance
| | - Robert Ptacnik
- WasserCluster Lunz – Biological StationLunz am SeeAustria
| | - Matthias Pilecky
- WasserCluster Lunz – Biological StationLunz am SeeAustria
- Donau‐Universität KremsKremsAustria
| | - Martin J. Kainz
- WasserCluster Lunz – Biological StationLunz am SeeAustria
- Donau‐Universität KremsKremsAustria
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To Die or Not to Die—Regulated Cell Death and Survival in Cyanobacteria. Microorganisms 2022; 10:microorganisms10081657. [PMID: 36014075 PMCID: PMC9415839 DOI: 10.3390/microorganisms10081657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/06/2022] [Accepted: 08/12/2022] [Indexed: 11/24/2022] Open
Abstract
Regulated cell death (RCD) is central to the development, integrity, and functionality of multicellular organisms. In the last decade, evidence has accumulated that RCD is a universal phenomenon in all life domains. Cyanobacteria are of specific interest due to their importance in aquatic and terrestrial habitats and their role as primary producers in global nutrient cycling. Current knowledge on cyanobacterial RCD is based mainly on biochemical and morphological observations, often by methods directly transferred from vertebrate research and with limited understanding of the molecular genetic basis. However, the metabolism of different cyanobacteria groups relies on photosynthesis and nitrogen fixation, whereas mitochondria are the central executioner of cell death in vertebrates. Moreover, cyanobacteria chosen as biological models in RCD studies are mainly colonial or filamentous multicellular organisms. On the other hand, unicellular cyanobacteria have regulated programs of cellular survival (RCS) such as chlorosis and post-chlorosis resuscitation. The co-existence of different genetically regulated programs in cyanobacterial populations may have been a top engine in life diversification. Development of cyanobacteria-specific methods for identification and characterization of RCD and wider use of single-cell analysis combined with intelligent image-based cell sorting and metagenomics would shed more light on the underlying molecular mechanisms and help us to address the complex colonial interactions during these events. In this review, we focus on the functional implications of RCD in cyanobacterial communities.
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Characterizing the "fungal shunt": Parasitic fungi on diatoms affect carbon flow and bacterial communities in aquatic microbial food webs. Proc Natl Acad Sci U S A 2021; 118:2102225118. [PMID: 34074785 PMCID: PMC8201943 DOI: 10.1073/pnas.2102225118] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Planktonic microorganisms interact with each other in multifarious ways, ultimately catalyzing the flow of carbon and energy in diverse aquatic environments. However, crucial links associated with eukaryotic microparasites are still overlooked in planktonic networks. We addressed such links by studying cryptic interactions between parasitic fungi, phytoplankton, and bacteria using a model pathosystem. Our results demonstrate that parasitic fungi profoundly modified microbial interactions through several mechanisms (e.g., transferring photosynthetic carbon to infecting fungi, stimulating bacterial colonization on phytoplankton cells, and altering the community composition of bacteria and their acquisition of photosynthetic carbon). Hence, fungal microparasites can substantially shape the microbially mediated carbon flow at the base of aquatic food webs and should be considered as crucial members within plankton communities. Microbial interactions in aquatic environments profoundly affect global biogeochemical cycles, but the role of microparasites has been largely overlooked. Using a model pathosystem, we studied hitherto cryptic interactions between microparasitic fungi (chytrid Rhizophydiales), their diatom host Asterionella, and cell-associated and free-living bacteria. We analyzed the effect of fungal infections on microbial abundances, bacterial taxonomy, cell-to-cell carbon transfer, and cell-specific nitrate-based growth using microscopy (e.g., fluorescence in situ hybridization), 16S rRNA gene amplicon sequencing, and secondary ion mass spectrometry. Bacterial abundances were 2 to 4 times higher on individual fungal-infected diatoms compared to healthy diatoms, particularly involving Burkholderiales. Furthermore, taxonomic compositions of both diatom-associated and free-living bacteria were significantly different between noninfected and fungal-infected cocultures. The fungal microparasite, including diatom-associated sporangia and free-swimming zoospores, derived ∼100% of their carbon content from the diatom. By comparison, transfer efficiencies of photosynthetic carbon were lower to diatom-associated bacteria (67 to 98%), with a high cell-to-cell variability, and even lower to free-living bacteria (32%). Likewise, nitrate-based growth for the diatom and fungi was synchronized and faster than for diatom-associated and free-living bacteria. In a natural lacustrine system, where infection prevalence reached 54%, we calculated that 20% of the total diatom-derived photosynthetic carbon was shunted to the parasitic fungi, which can be grazed by zooplankton, thereby accelerating carbon transfer to higher trophic levels and bypassing the microbial loop. The herein termed “fungal shunt” can thus significantly modify the fate of photosynthetic carbon and the nature of phytoplankton–bacteria interactions, with implications for diverse pelagic food webs and global biogeochemical cycles.
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Dick GJ, Duhaime MB, Evans JT, Errera RM, Godwin CM, Kharbush JJ, Nitschky HS, Powers MA, Vanderploeg HA, Schmidt KC, Smith DJ, Yancey CE, Zwiers CC, Denef VJ. The genetic and ecophysiological diversity of Microcystis. Environ Microbiol 2021; 23:7278-7313. [PMID: 34056822 DOI: 10.1111/1462-2920.15615] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 05/24/2021] [Accepted: 05/27/2021] [Indexed: 01/30/2023]
Abstract
Microcystis is a cyanobacterium that forms toxic blooms in freshwater ecosystems around the world. Biological variation among taxa within the genus is apparent through genetic and phenotypic differences between strains and via the spatial and temporal distribution of strains in the environment, and this fine-scale diversity exerts strong influence over bloom toxicity. Yet we do not know how varying traits of Microcystis strains govern their environmental distribution, the tradeoffs and links between these traits, or how they are encoded at the genomic level. Here we synthesize current knowledge on the importance of diversity within Microcystis and on the genes and traits that likely underpin ecological differentiation of taxa. We briefly review spatial and environmental patterns of Microcystis diversity in the field and genetic evidence for cohesive groups within Microcystis. We then compile data on strain-level diversity regarding growth responses to environmental conditions and explore evidence for variation of community interactions across Microcystis strains. Potential links and tradeoffs between traits are identified and discussed. The resulting picture, while incomplete, highlights key knowledge gaps that need to be filled to enable new models for predicting strain-level dynamics, which influence the development, toxicity and cosmopolitan nature of Microcystis blooms.
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Affiliation(s)
- Gregory J Dick
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA.,Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Melissa B Duhaime
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Jacob T Evans
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Reagan M Errera
- National Oceanographic and Atmospheric Administration Great Lakes Environmental Research Lab, Ann Arbor, MI, USA
| | - Casey M Godwin
- School for Environment and Sustainability, Cooperative Institute for Great Lakes Research, University of Michigan, Ann Arbor, MI, USA
| | - Jenan J Kharbush
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Helena S Nitschky
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - McKenzie A Powers
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Henry A Vanderploeg
- National Oceanographic and Atmospheric Administration Great Lakes Environmental Research Lab, Ann Arbor, MI, USA
| | - Kathryn C Schmidt
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Derek J Smith
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Colleen E Yancey
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Claire C Zwiers
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Vincent J Denef
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
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10
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Bauer A, Forchhammer K. Bacterial Predation on Cyanobacteria. Microb Physiol 2021; 31:99-108. [PMID: 34010833 DOI: 10.1159/000516427] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 04/07/2021] [Indexed: 11/19/2022]
Abstract
Predatory bacteria gained interest in the last 20 years. Nevertheless, only a few species are well characterized. The endobiotic predator Bdellovibrio bacteriovorus invades its prey to consume it from the inside, whereas Myxococcus xanthus hunts as a whole group to overcome its prey. Both species were described to prey on cyanobacteria as well. This minireview summarizes the findings of the last 20 years of predatory bacteria of cyanobacteria and is supplemented by new findings from a screening experiment for bacterial predators of the model organism Anabaena variabilis PCC 7937. Known predatory bacteria of cyanobacteria belong to the phyla Proteobacteria, Bacteroidetes, and Firmicutes and follow different hunting strategies. The underlying mechanisms are in most cases not known in much detail. Isolates from the screening experiment were clustered after predation behaviour and analyzed with respect to their size. The effect of predation in high nitrate levels and the occurrence of nitrogen-fixing cells, called heterocysts, are addressed.
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Affiliation(s)
- Antje Bauer
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls Universität, Tübingen, Germany
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls Universität, Tübingen, Germany
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Alors D, Boussiba S, Zarka A. Paraphysoderma sedebokerense Infection in Three Economically Valuable Microalgae: Host Preference Correlates with Parasite Fitness. J Fungi (Basel) 2021; 7:jof7020100. [PMID: 33535515 PMCID: PMC7912770 DOI: 10.3390/jof7020100] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 01/25/2021] [Accepted: 01/28/2021] [Indexed: 11/27/2022] Open
Abstract
The blastocladialean fungus Paraphysoderma sedebokerense parasitizes three microalgae species of economic interest: Haematococcus pluvialis, Chromochloris zofingiensis and Scenedesmus dimorphus. For the first time, we characterized the developmental stages of isolated fungal propagules in H. pluvialis co-culture, finding a generation time of 16 h. We established a patho-system to compare the infection in the three different host species for 48 h, with two different setups to quantify parameters of the infection and parameters of the parasite fitness. The prevalence of the parasite in H. pluvialis and C. zofingiensis cultures was 100%, but only 20% in S. dimorphus culture. The infection of S. dimorphus not only reached lower prevalence but was also qualitatively different; the infection developed preferentially on senescent cells and more resting cysts were produced, being consistent with a reservoir host. In addition, we carried out cross infection experiments and the inoculation of a mixed algal culture containing the three microalgae, to determine the susceptibility of the host species and to investigate the preference of P. sedebokerense for these microalgae. The three tested microalgae showed different susceptibility to P. sedebokerense, which correlates with blastoclad’s preference to the host in the following order: H. pluvialis > C. zofingiensis > S. dimorphus.
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12
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Isolation and Characterization of Rhizophydiales sp. (Chytridiomycota), Obligate Parasite of Planktothrix agardhii in a Laurentian Great Lakes Embayment. Appl Environ Microbiol 2021; 87:AEM.02308-20. [PMID: 33310722 PMCID: PMC7851699 DOI: 10.1128/aem.02308-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Planktothrix agardhii dominates the cyanobacterial harmful algal bloom community in Sandusky Bay, Lake Erie (USA) from May through September. This filamentous cyanobacterium is host to a known obligate parasite; the chytrid Rhizophydium sp. During the 2018 bloom season, by utilizing dilution and single filament isolation techniques, 7 chytrid and 12 P. agardhii strains were isolated from Sandusky Bay. These 7 chytrids and a selection of P. agardhii hosts were then characterized with respect to infection rates. Infections by the isolated chytrids were specific to Planktothrix planktonic species and were not found on other filamentous cyanobacterial taxa present in the bay (Aphanizomenon sp. and Cuspidothrix sp.). Even among the potential P. agardhii host strains, individual chytrid isolates had different degrees of infectivity and showed preference for different host isolates, suggesting possible ecological partitioning even within the same sample population. Examining mechanisms of chytrid pathogenesis, the zoospores displayed a swarming pattern to attack and fracture the host filament and create new infection sites at the trichome termini. Infections by these parasitic chytrids also led to a release of intracellular microcystin toxins from the hosts. Additionally, infections were dependent on media type, highlighting the importance of media choice on experimental outcomes. Media in which chytrid swarming was observed closely matched the ionic strength of the natural environment. Understanding pathogenesis by fungal parasites will assist future efforts aimed at determining environmental factors favoring loss mechanisms for Planktothrix agardhii-dominated blooms.IMPORTANCE Whereas many studies have focused on the factors contributing to the establishment and persistence of cyanobacterial harmful algal blooms (cHABs), few studies have examined bloom pathogenesis. Chytrid fungi infect cyanobacteria and stimulate food web interactions through manipulation of previously hard to digest filaments and the release of nutrients to support heterotrophic microbes. Specifically, chytrids infective on filamentous Planktothrix agardhii exhibit a species-specific infection that fragments trichomes into shorter units that can be consumed more easily by grazers. Chytrid zoospores also serve as a high-quality food source for the lower food web. Understanding host-pathogen relationships and mechanisms of pathogenesis on cyanobacteria will be necessary to effectively model the ecology of cHABs.
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Weisbrod B, Riehle E, Helmer M, Martin-Creuzburg D, Dietrich DR. Can toxin warfare against fungal parasitism influence short-term Dolichospermum bloom dynamics? - A field observation. HARMFUL ALGAE 2020; 99:101915. [PMID: 33218440 DOI: 10.1016/j.hal.2020.101915] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/20/2020] [Accepted: 10/04/2020] [Indexed: 06/11/2023]
Abstract
Cyanobacterial blooms often consist of numerous co-existing cyanobacterial species, with predominant taxa dynamically varying intra-annually. Parasitism by fungi (chytrids) has come into focus as an important factor driving short-term bloom dynamics. Using microscopic analysis, Illumina sequencing and cyanobacterial toxin analyses, we monitored the seasonal succession of Dolichospermum blooms in a reservoir along with environmental parameters. We identified two consecutive Dolichospermum blooms that were characterized by a straight and a coiled morphotype, separated by a complete bloom collapse. Phylotyping provided evidence for three putative Dolichospermum amplicon sequence variants (ASVs); i.e. Dolichospermum1 & 2 in the first bloom (straight filaments) and Dolichospermum3 in the second bloom (coiled filaments). Morphotype succession as well as total filament concentration did not correlate with any of the measured environmental parameters. Fungal parasitism by the chytrid Rhizosiphon crassum occurred in straight Dolichospermum filaments only. Coiled filaments showed no infection despite ambient presence of chytrids, deduced from fungal ASVs, throughout the entire observation period. Toxin concentrations (microcystins (MCs) and anabaenopeptins) correlated significantly with the abundance of the straight Dolichospermum morphotype. Enhanced cyanotoxin biosynthesis in the straight Dolichospermum morphotype, interpreted as a defensive reaction to fungal parasitism, appeared to come at the expense of lowered competitiveness with the co-occurring coiled morphotype. Our findings support the hypothesis that selective parasitism by chytrids is an important factor driving short-term morphotype and toxin dynamics within cyanobacterial blooms.
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Affiliation(s)
- B Weisbrod
- Human and Environmental Toxicology, University of Konstanz, Universitätsstrasse 10, 78464 Konstanz, Germany.
| | - E Riehle
- Human and Environmental Toxicology, University of Konstanz, Universitätsstrasse 10, 78464 Konstanz, Germany
| | - M Helmer
- Limnological Institute, University of Konstanz, Mainaustrasse 252, 78464 Konstanz, Germany
| | - D Martin-Creuzburg
- Limnological Institute, University of Konstanz, Mainaustrasse 252, 78464 Konstanz, Germany
| | - D R Dietrich
- Human and Environmental Toxicology, University of Konstanz, Universitätsstrasse 10, 78464 Konstanz, Germany
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14
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Banos S, Gysi DM, Richter-Heitmann T, Glöckner FO, Boersma M, Wiltshire KH, Gerdts G, Wichels A, Reich M. Seasonal Dynamics of Pelagic Mycoplanktonic Communities: Interplay of Taxon Abundance, Temporal Occurrence, and Biotic Interactions. Front Microbiol 2020; 11:1305. [PMID: 32676057 PMCID: PMC7333250 DOI: 10.3389/fmicb.2020.01305] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 05/22/2020] [Indexed: 12/14/2022] Open
Abstract
Marine fungi are an important component of pelagic planktonic communities. However, it is not yet clear how individual fungal taxa are integrated in marine processes of the microbial loop and food webs. Most likely, biotic interactions play a major role in shaping the fungal community structure. Thus, the aim of our work was to identify possible biotic interactions of mycoplankton with phytoplankton and zooplankton groups and among fungi, and to investigate whether there is coherence between interactions and the dynamics, abundance and temporal occurrence of individual fungal OTUs. Marine surface water was sampled weekly over the course of 1 year, in the vicinity of the island of Helgoland in the German Bight (North Sea). The mycoplankton community was analyzed using 18S rRNA gene tag-sequencing and the identified dynamics were correlated to environmental data including phytoplankton, zooplankton, and abiotic factors. Finally, co-occurrence patterns of fungal taxa were detected with network analyses based on weighted topological overlaps (wTO). Of all abundant and persistent OTUs, 77% showed no biotic relations suggesting a saprotrophic lifestyle. Of all other fungal OTUs, nearly the half (44%) had at least one significant negative relationship, especially with zooplankton and other fungi, or to a lesser extent with phytoplankton. These findings suggest that mycoplankton OTUs are embedded into marine food web chains via highly complex and manifold relationships such as parasitism, predation, grazing, or allelopathy. Furthermore, about one third of all rare OTUs were part of a dense fungal co-occurrence network probably stabilizing the fungal community against environmental changes and acting as functional guilds or being involved in fungal cross-feeding. Placed in an ecological context, strong antagonistic relationships of the mycoplankton community with other components of the plankton suggest that: (i) there is a top-down control by fungi on zooplankton and phytoplankton; (ii) fungi serve as a food source for zooplankton and thereby transfer nutrients and organic material; (iii) the dynamics of fungi harmful to other plankton groups are controlled by antagonistic fungal taxa.
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Affiliation(s)
- Stefanos Banos
- Molecular Ecology Group, University of Bremen, Bremen, Germany
| | - Deisy Morselli Gysi
- Department of Computer Science, Interdisciplinary Center of Bioinformatics, University of Leipzig, Leipzig, Germany.,Swarm Intelligence and Complex Systems Group, Faculty of Mathematics and Computer Science, University of Leipzig, Leipzig, Germany.,Center for Complex Networks Research, Northeastern University, Boston, MA, United States
| | | | - Frank Oliver Glöckner
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany.,Department of Life Sciences and Chemistry, Jacobs University Bremen gGmbH, Bremen, Germany.,MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Maarten Boersma
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Biologische Anstalt Helgoland, Helgoland, Germany.,FB2, University of Bremen, Bremen, Germany
| | - Karen H Wiltshire
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Biologische Anstalt Helgoland, Helgoland, Germany.,Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Wattenmeerstation, List, Germany
| | - Gunnar Gerdts
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Biologische Anstalt Helgoland, Helgoland, Germany
| | - Antje Wichels
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Biologische Anstalt Helgoland, Helgoland, Germany
| | - Marlis Reich
- Molecular Ecology Group, University of Bremen, Bremen, Germany
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15
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Dunker S. Imaging Flow Cytometry for Phylogenetic and MorphologicallyBased Functional Group Clustering of a Natural Phytoplankton Community over 1 Year in an Urban Pond. Cytometry A 2020; 97:727-736. [PMID: 32472660 DOI: 10.1002/cyto.a.24044] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 05/08/2020] [Accepted: 05/11/2020] [Indexed: 11/10/2022]
Abstract
Ponds are an insufficiently studied research object but represent a biodiversity hotspot and have a high value for ecosystem services like recreation, water retention, or angling. Especially urban ponds create a direct contact for citizens experiencing nature. But on the other side, these systems also suffer from several pressures caused by humans, for example, high nutrient and salt influxes or high temperatures. Phytoplankton organisms are a crucial part of ponds ecosystem and an understanding of community composition is crucial especially when eutrophication and high temperatures lead to dominance of unpleasant toxic cyanobacteria. With traditional microscopic methods for phytoplankton analysis, monitoring is not feasible with high spatial resolution and frequency. Therefore, a new approach of imaging flow cytometry to classify phytoplankton species in either taxonomic or morphologically based functional groups (MBFGs) is suggested. In this study, both classifications could be successfully applied to a natural phytoplankton community in an urban pond in Leipzig with minor modifications. Both classifications in combination provide a good mechanistic understanding of phytoplankton community dynamics. In addition, a great advantage of the measurements is the archivability of microscopic images allowing a comprehensive respective data analysis. Two examples of detailed trait and image analysis are demonstrated to investigate single-cell traits for cyanobacteria and chlorophytes/euglenophytes and to follow the fate of a cyanobacterial bloom affected by a fungal infection. © 2020 The Author. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of International Society for Advancement of Cytometry.
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Affiliation(s)
- Susanne Dunker
- Helmholtz-Centre for Environmental Research - UFZ, Department Physiological Diversity, Permoserstraße 15 Leipzig, 04318, Germany.,German Centre for Integrative Biodiversity Research - iDiv, Department Physiological Diversity, Deutscher Platz 5e, Leipzig, 04103, Germany
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16
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Lu T, Xu N, Zhang Q, Zhang Z, Debognies A, Zhou Z, Sun L, Qian H. Understanding the influence of glyphosate on the structure and function of freshwater microbial community in a microcosm. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 260:114012. [PMID: 31995771 DOI: 10.1016/j.envpol.2020.114012] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/29/2019] [Accepted: 01/16/2020] [Indexed: 05/07/2023]
Abstract
Glyphosate, one of the most popular herbicides, has become a prominent aquatic contaminant because of its huge usage. The eco-safety of glyphosate is still in controversy, and it is inconclusive how glyphosate influences aquatic microbial communities. In the present study, the effects of glyphosate on the structure and function of microbial communities in a freshwater microcosm were investigated. 16S/18S rRNA gene sequencing results showed that glyphosate treatment (2.5 mg L-1, 15 days) did not significantly alter the physical and chemical condition of the microcosm or the composition of the main species in the community, but metatranscriptomic analyses indicated that the transcriptions of some cyanobacteria were significantly influenced by glyphosate. The microbial community enhanced the gene expression in pathways related to translation, secondary metabolites biosynthesis, transport and catabolism to potentially withstand glyphosate contamination. In the low phosphorus (P) environment, a common cyanobacterium, Synechococcus, plays a special role by utilizing glyphosate as P source and thus reducing its toxicity to other microbes, such as Pseudanabaena. In general, addition of glyphosate in our artificial microcosms did not strongly affect the aquatic microbial community composition but did alter the community's transcription levels, which might be potentially explained by that some microbes could alleviate glyphosate's toxicity by utilizing glyphosate as a P source.
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Affiliation(s)
- Tao Lu
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, PR China
| | - Nuohan Xu
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, PR China
| | - Qi Zhang
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, PR China
| | - Zhenyan Zhang
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, PR China
| | - Andries Debognies
- Faculty of Bioscience Engineering, Ghent University Campus Kortrijk, Graaf Karel de Goedelaan 5, 8500, Kortrijk, Belgium
| | - Zhigao Zhou
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, PR China
| | - Liwei Sun
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, PR China
| | - Haifeng Qian
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, PR China.
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17
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Garrido-Benavent I, Pérez-Ortega S, Durán J, Ascaso C, Pointing SB, Rodríguez-Cielos R, Navarro F, de los Ríos A. Differential Colonization and Succession of Microbial Communities in Rock and Soil Substrates on a Maritime Antarctic Glacier Forefield. Front Microbiol 2020; 11:126. [PMID: 32117148 PMCID: PMC7018881 DOI: 10.3389/fmicb.2020.00126] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 01/20/2020] [Indexed: 12/20/2022] Open
Abstract
Glacier forefields provide a unique chronosequence to assess microbial or plant colonization and ecological succession on previously uncolonized substrates. Patterns of microbial succession in soils of alpine and subpolar glacier forefields are well documented but those affecting high polar systems, including moraine rocks, remain largely unexplored. In this study, we examine succession patterns in pioneering bacterial, fungal and algal communities developing on moraine rocks and soil at the Hurd Glacier forefield (Livingston Island, Antarctica). Over time, changes were produced in the microbial community structure of rocks and soils (ice-free for different lengths of time), which differed between both substrates across the entire chronosequence, especially for bacteria and fungi. In addition, fungal and bacterial communities showed more compositional consistency in soils than rocks, suggesting community assembly in each niche could be controlled by processes operating at different temporal and spatial scales. Microscopy revealed a patchy distribution of epilithic and endolithic lithobionts, and increasing endolithic colonization and microbial community complexity along the chronosequence. We conclude that, within relatively short time intervals, primary succession processes at polar latitudes involve significant and distinct changes in edaphic and lithic microbial communities associated with soil development and cryptogamic colonization.
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Affiliation(s)
- Isaac Garrido-Benavent
- Departamento de Biogeoquímica y Ecología Microbiana, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
| | | | - Jorge Durán
- Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Carmen Ascaso
- Departamento de Biogeoquímica y Ecología Microbiana, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
| | - Stephen B. Pointing
- Yale-NUS College, National University of Singapore, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Ricardo Rodríguez-Cielos
- ETSI de Telecomunicación, Departamento de Señales, Sistemas y Radiocomunicaciones, Universidad Politécnica de Madrid, Madrid, Spain
| | - Francisco Navarro
- ETSI de Telecomunicación, Departamento de Matemática Aplicada a las TIC, Universidad Politécnica de Madrid, Madrid, Spain
| | - Asunción de los Ríos
- Departamento de Biogeoquímica y Ecología Microbiana, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
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18
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Biological contamination and its chemical control in microalgal mass cultures. Appl Microbiol Biotechnol 2019; 103:9345-9358. [PMID: 31720774 DOI: 10.1007/s00253-019-10193-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/29/2019] [Accepted: 10/07/2019] [Indexed: 12/18/2022]
Abstract
Microalgae are versatile sources of bioproducts, a solution for many environmental problems. However, and despite its importance, one of the main problems in large-scale cultures-the presence of contaminants-is rarely systematically approached. Contamination, or the presence of undesirable organisms in a culture, is deleterious for the culture and frequently leads to culture crashes. To avoid contamination, closed systems can be used; however, for very large-scale open systems, contamination is unavoidable and remediation procedures are necessary-ranging from physicochemical treatment to addition of biocidal substances. In all cases, early detection and culture monitoring are paramount. This article describes the biological contaminants, contamination mechanisms, and control systems used in open and closed cultures, discussing the latest advances and techniques in the area. It also discusses the complex interactions of algae with other microorganisms that can be expected in cultivation systems.
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19
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Legrand B, Miras Y, Beauger A, Dussauze M, Latour D. Akinetes and ancient DNA reveal toxic cyanobacterial recurrences and their potential for resurrection in a 6700-year-old core from a eutrophic lake. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 687:1369-1380. [PMID: 31412470 DOI: 10.1016/j.scitotenv.2019.07.100] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 06/20/2019] [Accepted: 07/07/2019] [Indexed: 06/10/2023]
Abstract
In order to evaluate the recurrence of toxic cyanobacterial blooms and to determine the survival capabilities of the resistance cells through time, a sedimentary core spanning 6700 years was drilled in the eutrophic Lake Aydat. A multiproxy approach (density, magnetic susceptibility, XRF, pollen and non-pollen palynomorph analyses), was used initially to determine the sedimentation model and the land uses around the lake. Comparison with the akinete count revealed that Nostocales cyanobacteria have been present in Lake Aydat over a six thousand year period. This long-term cyanobacterial recurrence also highlights the past presence of both the anaC and mcyB genes, involved in anatoxin-a and microcystin biosynthesis, respectively, throughout the core. The first appearance of cyanobacteria seems to be linked to the natural damming of the river, while the large increase in akinete density around 1800 cal.yr BP can be correlated with the intensification of human activities (woodland clearance, crop planting, grazing, etc.) in the catchment area of the lake, and marks the beginning of a long period of eutrophication. This first investigation into the viability and germination potential of cyanobacteria over thousands of years reveals the ability of intact akinetes to undergo cell divisions even after 1800 years of sedimentation, which is 10 times longer than previously observed. This exceptional cellular resistance, coupled with the long-term eutrophic conditions of this lake, could partly explain the past and current recurrences of cyanobacterial proliferations.
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Affiliation(s)
- Benjamin Legrand
- Université Clermont Auvergne, CNRS, LMGE, F-63178 Aubière Cedex, France; ATHOS Environnement, 112 avenue du Brézet, 63100 Clermont-Ferrand, France.
| | - Yannick Miras
- Histoire Naturelle de l'Homme Préhistorique (HNHP), UMR 7194, CNRS, Département de Préhistoire, Muséum National d'Histoire Naturelle, Institut de Paléontologie Humaine, 1, rue René Panhard, 75013 Paris, France; GEOLAB, UMR 6042, CNRS, Université Clermont-Auvergne, F-63000 Clermont-Ferrand, France
| | - Aude Beauger
- GEOLAB, UMR 6042, CNRS, Université Clermont-Auvergne, F-63000 Clermont-Ferrand, France
| | - Matthieu Dussauze
- Université Clermont Auvergne, CNRS, LMGE, F-63178 Aubière Cedex, France
| | - Delphine Latour
- Université Clermont Auvergne, CNRS, LMGE, F-63178 Aubière Cedex, France
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20
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Lu T, Zhang Q, Lavoie M, Zhu Y, Ye Y, Yang J, Paerl HW, Qian H, Zhu YG. The fungicide azoxystrobin promotes freshwater cyanobacterial dominance through altering competition. MICROBIOME 2019; 7:128. [PMID: 31484554 PMCID: PMC6727577 DOI: 10.1186/s40168-019-0744-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 08/26/2019] [Indexed: 05/19/2023]
Abstract
BACKGROUND Sharp increases in food production worldwide are attributable to agricultural intensification aided by heavy use of agrochemicals. This massive use of pesticides and fertilizers in combination with global climate change has led to collateral damage in freshwater systems, notably an increase in the frequency of harmful cyanobacterial blooms (HCBs). The precise mechanisms and magnitude of effects that pesticides exert on HCBs formation and proliferation have received little research attention and are poorly constrained. RESULTS We found that azoxystrobin (AZ), a common strobilurin fungicide, can favor cyanobacterial growth through growth inhibition of eukaryotic competitors (Chlorophyta) and possibly by inhibiting cyanobacterial parasites (fungi) as well as pathogenic bacteria and viruses. Meta-transcriptomic analyses identified AZ-responsive genes and biochemical pathways in eukaryotic plankton and bacteria, potentially explaining the microbial effects of AZ. CONCLUSIONS Our study provides novel mechanistic insights into the intertwined effects of a fungicide and eutrophication on microbial planktonic communities and cyanobacterial blooms in a eutrophic freshwater ecosystem. This knowledge may prove useful in mitigating cyanobacteria blooms resulting from agricultural intensification.
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Affiliation(s)
- Tao Lu
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032 People’s Republic of China
| | - Qi Zhang
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032 People’s Republic of China
| | - Michel Lavoie
- Quebec-Ocean and Takuvik Joint International Research Unit, Université Laval, G1VOA6, Québec, Canada
| | - Youchao Zhu
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032 People’s Republic of China
| | - Yizhi Ye
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032 People’s Republic of China
| | - Jun Yang
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 People’s Republic of China
| | - Hans W. Paerl
- Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, NC 28557 USA
- College of Environment, Hohai University, Nanjing, 210098 People’s Republic of China
| | - Haifeng Qian
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032 People’s Republic of China
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011 People’s Republic of China
| | - Yong-Guan Zhu
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 People’s Republic of China
- State Key Lab of Urban and Regional Ecology, Research Center for Ecoenvironmental Sciences, Chinese Academy of Sciences, Beijing, 100085 People’s Republic of China
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21
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A High-Resolution Time Series Reveals Distinct Seasonal Patterns of Planktonic Fungi at a Temperate Coastal Ocean Site (Beaufort, North Carolina, USA). Appl Environ Microbiol 2018; 84:AEM.00967-18. [PMID: 30143506 DOI: 10.1128/aem.00967-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 08/17/2018] [Indexed: 11/20/2022] Open
Abstract
There is a growing awareness of the ecological and biogeochemical importance of fungi in coastal marine systems. While highly diverse fungi have been discovered in these marine systems, still, little is known about their seasonality and associated drivers in coastal waters. Here, we examined fungal communities over 3 years of weekly sampling at a dynamic, temperate coastal site (Pivers Island Coastal Observatory [PICO], Beaufort, NC, USA). Fungal 18S rRNA gene abundance, operational taxonomic unit (OTU) richness, and Shannon's diversity index values exhibited prominent seasonality. Fungal 18S rRNA gene copies peaked in abundance during the summer and fall, with positive correlations with chlorophyll a, SiO4, and oxygen saturation. Diversity (measured using internal transcribed spacer [ITS] libraries) was highest during winter and lowest during summer; it was linked to temperature, pH, chlorophyll a, insolation, salinity, and dissolved inorganic carbon (DIC). Fungal communities derived from ITS libraries were dominated throughout the year by Ascomycota, with contributions from Basidiomycota, Chytridiomycota, and Mucoromycotina, and their seasonal patterns linked to water temperature, light, and the carbonate system. Network analysis revealed that while cooccurrence and exclusion existed within fungus networks, exclusion dominated the fungus-and-phytoplankton network, in contrast with reported pathogenic and nutritional interactions between marine phytoplankton and fungi. Compared with the seasonality of bacterial communities in the same samples, the timing, extent, and associated environmental variables for fungi community are unique. These results highlight the fungal seasonal dynamics in coastal water and improve our understanding of the ecology of planktonic fungi.IMPORTANCE Coastal fungal dynamics were long assumed to be due to terrestrial inputs; here, a high-resolution time series reveals strong, repeating annual patterns linked to in situ environmental conditions, arguing for a resident coastal fungal community shaped by environmental factors. These seasonal patterns do, however, differ from those observed in the bacterioplankton at the same site; e.g., fungal diversity peaks in winter, whereas bacterial diversity maxima occur in the spring and fall. While the dynamics of these communities are linked to water temperature and insolation, fungi are also influenced by the carbonate system (pH and DIC). As both fungi and heterotrophic bacteria are thought to be key organic-material metabolizers, differences in their environmental drivers may offer clues as to which group dominates secondary production at this dynamic site. Overall, this study suggests the unique ecological roles of mycoplankton and their potentially broad niche complementarities to other microbial groups in the coastal ocean.
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Qiu Y, Tian S, Gu L, Hildreth M, Zhou R. Identification of surface polysaccharides in akinetes, heterocysts and vegetative cells of Anabaena cylindrica using fluorescein-labeled lectins. Arch Microbiol 2018; 201:17-25. [PMID: 30173343 DOI: 10.1007/s00203-018-1565-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/10/2018] [Accepted: 08/22/2018] [Indexed: 11/26/2022]
Abstract
In response to environmental changes, Anabaena cylindrica differentiate three cell types: vegetative cells for photosynthesis, heterocysts for nitrogen fixation, and akinetes for stress survival. Cell-surface polysaccharides play important roles in cyanobacterial ecophysiology. In this study, specific cell-surface sugars were discovered in heterocysts, akinetes and vegetative cells of A. cylindrica using 20 fluorescein-labeled lectins. Both N-acetylglucosamine-binding lectins WGA and succinylated WGA bound specifically to the vegetative cells. Akinetes bound to three mannose-binding lectins (LCA, PSA, and ConA), and one of the galactose-binding lectins (GSL-I). Heterocyst also bound to ConA. However, the heterocysts in all4388 mutant of Anabaena sp. PCC 7120, in which the putative polysaccharide export protein gene all4388 was disrupted, exhibited diminished binding to ConA. Identification of distinct cell-surface sugar helped us to understand the role of polysaccharide for each cell type. Fluorescence-activated cell sorting may be applicable in isolating each cell type for comparative "omics" studies among the three cell types.
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Affiliation(s)
- Yeyan Qiu
- Department of Biology and Microbiology, South Dakota State University, Brookings, USA
| | - Shengni Tian
- College of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Liping Gu
- Department of Biology and Microbiology, South Dakota State University, Brookings, USA
| | - Michael Hildreth
- Department of Biology and Microbiology, South Dakota State University, Brookings, USA
| | - Ruanbao Zhou
- Department of Biology and Microbiology, South Dakota State University, Brookings, USA.
- BioSNTR, South Dakota State University, Brookings, SD, USA.
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Rohrlack T. Low temperatures can promote cyanobacterial bloom formation by providing refuge from microbial antagonists. AIMS Microbiol 2018; 4:304-318. [PMID: 31294217 PMCID: PMC6604935 DOI: 10.3934/microbiol.2018.2.304] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 04/08/2018] [Indexed: 11/25/2022] Open
Abstract
Freshwater cyanobacteria are prone to a wide range of highly potent microbial antagonists. Most of these exploit their prey in a frequency-dependent manner and are therefore particularly well suited to prevent any accumulation of cyanobacteria. Mass developments of cyanobacteria, the so-called blooms, should therefore be rare events, which is in striking contrast to what we actually see in nature. Laboratory experiments of the present study showed that the temperature range 5.8–10 °C forms a thermal refuge, inside which the cyanobacterium Planktothrix can grow without being exploited by two otherwise highly potent microbial antagonists. In nature, access of Planktothrix to this refuge was associated with positive net growth and a high probability of bloom formation, confirming that refuge temperatures indeed allow Planktothrix to grow with a minimum of biomass loss caused by microbial antagonists. Contact to higher temperatures, in contrast, was associated with decreases in net growth rate and in probability of bloom formation, with population collapses and with the occurrence of parasite infection. This is in agreement with the finding of laboratory experiments that above 10 °C exploitation of Planktothrix by multiple microbes increases in a temperature-dependent manner. Taken together, above findings suggest that temperature modulates the microbial control of natural Planktothrix populations. Low temperatures form a thermal refuge that may promote Planktothrix bloom formation by shielding the cyanobacterium from otherwise highly potent microbial antagonists.
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Affiliation(s)
- Thomas Rohrlack
- Norwegian University of Life Sciences, Faculty for Environmental Sciences and Natural Resource Management, Postbox 5003, NO-1432 Ås, Norway
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Microbial parasites make cyanobacteria blooms less of a trophic dead end than commonly assumed. ISME JOURNAL 2018; 12:1008-1020. [PMID: 29416126 DOI: 10.1038/s41396-018-0045-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 11/15/2017] [Accepted: 12/11/2017] [Indexed: 11/09/2022]
Abstract
Parasites exist in every ecosystem and can have large influence on food web structure and function, yet, we know little about parasites' effect on food web dynamics. Here we investigate the role of microbial parasitism (viruses of bacteria, phytoplankton and cyanobacteria, and parasitic chytrids on cyanobacteria) on the dynamics of trophic pathways and food web functioning during a cyanobacteria bloom, using linear inverse food web modeling parameterized with a 2-month long data set (biomasses, infection parameters, etc.). We show the importance of grazing on heterotrophic bacteria (the microbial pathway: DOC → bacteria → consumer) and how consumers depended on bacteria during peak-cyanobacteria bloom, which abundance was partly driven by the viral activity. As bacteria become the main energy pathway to the consumers, the system takes a more web-like structure through increased omnivory, and may thereby facilitate the system's persistence to the cyanobacteria outbreak. We also showed how the killing of cyanobacteria host cells by chytrids had important impact on the food web dynamics by facilitating grazing on the cyanobacteria, and by offering alternative pathways to the consumers. This seemed to increase the system's ability to return to a mix of trophic pathways, which theoretically increases the stability of the system.
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Akinetes May Be Representative of Past Nostocalean Blooms: a Case Study of Their Benthic Spatiotemporal Distribution and Potential for Germination in a Eutrophic Lake. Appl Environ Microbiol 2017; 83:AEM.01571-17. [PMID: 28970224 DOI: 10.1128/aem.01571-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 09/20/2017] [Indexed: 11/20/2022] Open
Abstract
Monitoring of water and surface sediment in a French eutrophic lake (Lake Aydat) was carried out over a 2-year period in order to determine whether akinetes in sediment could be representative of the most recent bloom and to estimate their germination potential. Sediment analysis revealed two akinete species, Dolichospermum macrosporum and Dolichospermumflos-aquae, present in the same proportions as observed for the pelagic populations. Moreover, similar spatial patterns observed for vegetative cells in the water column and akinete distributions in the sediment suggest that akinetes in the sediment may be representative of the previous bloom. However, the relationship between akinetes in the sediment and vegetative cells in the water column was not linear, and other factors may interfere. For example, our results highlighted horizontal transport of akinetes during the winter. The benthic overwinter phase did not seem to influence the percentages of intact akinetes, which remained stable at approximately 7% and 60% for D. macrosporum and D. flos-aquae, respectively. These percentages may thus be the result of processes that occurred in the water column. The intact overwintering akinetes showed germination rates of up to 90% after 72 h for D. flos-aquae or 144 h for D. macrosporum The difference in akinete germination rates between these two species demonstrates different ecological strategies, which serve to expand the window for germination in time and space and thus optimize colonization of the water column by nostocalean cyanobacteria.IMPORTANCE Cyanobacteria have the ability to proliferate and to form blooms. These blooms can then affect the local ecology, health, and economy. The akinete, a resistant cell type that persists in sediment, is an important intermediate phase between previous and future blooms. We monitored the water column and the surface sediment of a French eutrophic lake (Lake Aydat) to investigate the relationship between vegetative cells in the water column and akinetes in the sediment. This study focused on the characterization of spatiotemporal akinete distributions, cellular integrity, and germination potential. Species-specific ecological strategies were highlighted and may partly explain the temporal succession of species in the water column. Akinetes may also be used to understand past nostocalean blooms and to predict future ones.
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Sneed JM, Meickle T, Engene N, Reed S, Gunasekera S, Paul VJ. Bloom dynamics and chemical defenses of benthic cyanobacteria in the Indian River Lagoon, Florida. HARMFUL ALGAE 2017; 69:75-82. [PMID: 29122244 DOI: 10.1016/j.hal.2017.10.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 10/03/2017] [Accepted: 10/06/2017] [Indexed: 05/27/2023]
Abstract
Cyanobacterial blooms are predicted to become more prominent in the future as a result of increasing seawater temperatures and the continued addition of nutrients to coastal waters. Many benthic marine cyanobacteria have potent chemical defenses that protect them from top down pressures and contribute to the persistence of blooms. Blooms of benthic cyanobacteria have been observed along the coast of Florida and within the Indian River Lagoon (IRL), a biodiverse estuary system that spans 250km along Florida's east coast. In this study, the cyanobacterial bloom progression at three sites within the central IRL was monitored over the course of two summers. The blooms consisted of four unique cyanobacterial species, including the recently described Okeania erythroflocculosa. The cyanobacteria produced a range of known bioactive compounds including malyngolide, lyngbyoic acid, microcolins A-B, and desacetylmicrocolin B. Ecologically-relevant assays showed that malyngolide inhibited the growth of marine fungi (Dendryphiella salina and Lindra thalassiae); microcolins A-B and desacetylmicrocolin B inhibited feeding by a generalist herbivore, the sea urchin Lytechinus variegatus; and lyngbyoic acid inhibited fungal growth and herbivore feeding. These chemical defenses likely contribute to the persistence of cyanobacterial blooms in the IRL during the summer growing period.
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Affiliation(s)
- Jennifer M Sneed
- Smithsonian Marine Station at Fort Pierce, 701 Seaway Dr., Ft. Pierce, FL 34949, USA.
| | - Theresa Meickle
- Smithsonian Marine Station at Fort Pierce, 701 Seaway Dr., Ft. Pierce, FL 34949, USA
| | - Niclas Engene
- Smithsonian Marine Station at Fort Pierce, 701 Seaway Dr., Ft. Pierce, FL 34949, USA; Department of Biological Sciences, Florida International University, Miami, FL 33199, USA
| | - Sherry Reed
- Smithsonian Marine Station at Fort Pierce, 701 Seaway Dr., Ft. Pierce, FL 34949, USA
| | - Sarath Gunasekera
- Smithsonian Marine Station at Fort Pierce, 701 Seaway Dr., Ft. Pierce, FL 34949, USA
| | - Valerie J Paul
- Smithsonian Marine Station at Fort Pierce, 701 Seaway Dr., Ft. Pierce, FL 34949, USA
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27
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Sun JY, Song Y, Ma ZP, Zhang HJ, Yang ZD, Cai ZH, Zhou J. Fungal community dynamics during a marine dinoflagellate (Noctiluca scintillans) bloom. MARINE ENVIRONMENTAL RESEARCH 2017; 131:183-194. [PMID: 29017729 DOI: 10.1016/j.marenvres.2017.10.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 09/27/2017] [Accepted: 10/02/2017] [Indexed: 06/07/2023]
Abstract
Contamination and eutrophication have caused serious ecological events (such as algal bloom) in coastal area. During this ecological process, microbial community structure is critical for algal bloom succession. The diversity and composition of bacteria and archaea communities in algal blooms have been widely investigated; however, those of fungi are poorly understood. To fill this gap, we used pyrosequencing and correlation approaches to assess fungal patterns and associations during a dinoflagellate (Noctiluca scintillans) bloom. Phylum level fungal types were predominated by Ascomycota, Chytridiomycota, Mucoromycotina, and Basidiomycota. At the genus level drastic changes were observed with Hysteropatella, Malassezia and Saitoella dominating during the initial bloom stage, while Malassezia was most abundant (>50%) during onset and peak-bloom stages. Saitoella and Lipomyces gradually became more abundant and, in the decline stage, contributed almost 70% of sequences. In the terminal stage of the bloom, Rozella increased rapidly to a maximum of 50-60%. Fungal population structure was significantly influenced by temperature and substrate (N and P) availability (P < 0.05). Inter-specific network analyses demonstrated that Rozella and Saitoella fungi strongly impacted the ecological trajectory of N. scintillans. The functional prediction show that symbiotrophic fungi was dominated in the onset stage; saprotroph type was the primary member present during the exponential growth period; whereas pathogentroph type fungi enriched in decline phase. Overall, fungal communities and functions correlated significantly with N. scintillans processes, suggesting that they may regulate dinoflagellate bloom fates. Our results will facilitate deeper understanding of the ecological importance of marine fungi and their roles in algal bloom formation and collapse.
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Affiliation(s)
- Jing-Yun Sun
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, Guangdong Province, PR China; School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, Gansu Province, PR China
| | - Yu Song
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, Guangdong Province, PR China
| | - Zhi-Ping Ma
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, Guangdong Province, PR China
| | - Huai-Jing Zhang
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, Guangdong Province, PR China
| | - Zhong-Duo Yang
- School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, Gansu Province, PR China; The Provincial Education Key Laboratory of Screening, Evaluation and Advanced Processing of Traditional Chinese Medicine and Tibetan Medicine, School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou, 730050, Gansu Province, PR China
| | - Zhong-Hua Cai
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, Guangdong Province, PR China.
| | - Jin Zhou
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, Guangdong Province, PR China.
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28
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Benthic Archives Reveal Recurrence and Dominance of Toxigenic Cyanobacteria in a Eutrophic Lake over the Last 220 Years. Toxins (Basel) 2017; 9:toxins9090271. [PMID: 28869578 PMCID: PMC5618204 DOI: 10.3390/toxins9090271] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 08/25/2017] [Accepted: 09/01/2017] [Indexed: 11/17/2022] Open
Abstract
Akinetes are resistant cells which have the ability to persist in sediment for several decades. We have investigated the temporal distribution of akinetes of two species, Dolichospermum macrosporum and Dolichospermum flos-aquae, in a sediment core sampled in Lake Aydat (France), which covers 220 years. The upper part, from 1907 to 2016, the number of akinetes fluctuated but stayed at high concentrations, especially for D. macrosporum in surface sediment (with the maximal value close to 6.10⁵ akinetes g DW-1 of sediment), suggesting a recurrence of blooms of this species which was probably closely related to anthropic eutrophication since the 1960s. Before 1907, the abundance of akinetes of both species was very low, suggesting only a modest presence of these cyanobacteria. In addition, the percentage of intact akinetes was different for each species, suggesting different ecological processes in the water column. This percentage also decreased with depth, revealing a reduction in germination potential over time. In addition, biosynthetic genes of anatoxin-a (anaC) and microcystin (mcyA) were detected. First results show a high occurrence of mcyA all down the core. In contrast, anaC gene was mostly detected in the surface sediment (since the 1980s), revealing a potentially more recent occurrence of this cyanotoxin in Lake Aydat which may be associated with the recurrence of blooms of D. macrosporum and thus with anthropic activities.
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29
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Thorel M, Claquin P, Schapira M, Le Gendre R, Riou P, Goux D, Le Roy B, Raimbault V, Deton-Cabanillas AF, Bazin P, Kientz-Bouchart V, Fauchot J. Nutrient ratios influence variability in Pseudo-nitzschia species diversity and particulate domoic acid production in the Bay of Seine (France). HARMFUL ALGAE 2017; 68:192-205. [PMID: 28962980 DOI: 10.1016/j.hal.2017.07.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 07/10/2017] [Accepted: 07/17/2017] [Indexed: 05/20/2023]
Abstract
The population dynamics of different Pseudo-nitzschia species, along with particulate domoic acid (pDA) concentrations, were studied from May 2012 to December 2013 in the Bay of Seine (English Channel, Normandy). While Pseudo-nitzschia spp. blooms occurred during the two years of study, Pseudo-nitzschia species diversity and particulate domoic acid concentrations varied greatly. In 2012, three different species were identified during the spring bloom (P. australis, P. pungens and P. fraudulenta) with high pDA concentrations (∼1400ngl-1) resulting in shellfish harvesting closures. In contrast, the 2013 spring was characterised by a P. delicatissima bloom without any toxic event. Above all, the results show that high pDA concentrations coincided with the presence of P. australis and with potential silicate limitation (Si:N<1), while nitrate concentrations were still replete. The contrasting environmental conditions between 2012 and 2013 highlight different environmental controls that might favour the development of either P. delicatissima or P. australis. This study points to the key role of Pseudo-nitzschia diversity and cellular toxicity in the control of particulate domoic acid variations and highlights the fact that diversity and toxicity are influenced by nutrients, especially nutrient ratios.
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Affiliation(s)
- Maxine Thorel
- Normandie Univ, UNICAEN, CNRS, BOREA, 14000 Caen, France; UMR BOREA, CNRS-7208, IRD-207, MNHN, UPMC, UCBN, 14032 Caen, France
| | - Pascal Claquin
- Normandie Univ, UNICAEN, CNRS, BOREA, 14000 Caen, France; UMR BOREA, CNRS-7208, IRD-207, MNHN, UPMC, UCBN, 14032 Caen, France
| | | | | | | | - Didier Goux
- CMAbio-SF 4206 ICORE UNICAEN, 14032 Caen, France
| | - Bertrand Le Roy
- Normandie Univ, UNICAEN, CNRS, BOREA, 14000 Caen, France; UMR BOREA, CNRS-7208, IRD-207, MNHN, UPMC, UCBN, 14032 Caen, France
| | - Virginie Raimbault
- Normandie Univ, UNICAEN, CNRS, BOREA, 14000 Caen, France; UMR BOREA, CNRS-7208, IRD-207, MNHN, UPMC, UCBN, 14032 Caen, France
| | - Anne-Flore Deton-Cabanillas
- Normandie Univ, UNICAEN, CNRS, BOREA, 14000 Caen, France; UMR BOREA, CNRS-7208, IRD-207, MNHN, UPMC, UCBN, 14032 Caen, France
| | - Pauline Bazin
- Normandie Univ, UNICAEN, CNRS, BOREA, 14000 Caen, France; UMR BOREA, CNRS-7208, IRD-207, MNHN, UPMC, UCBN, 14032 Caen, France
| | | | - Juliette Fauchot
- Normandie Univ, UNICAEN, CNRS, BOREA, 14000 Caen, France; UMR BOREA, CNRS-7208, IRD-207, MNHN, UPMC, UCBN, 14032 Caen, France.
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30
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Pancrace C, Jokela J, Sassoon N, Ganneau C, Desnos-Ollivier M, Wahlsten M, Humisto A, Calteau A, Bay S, Fewer DP, Sivonen K, Gugger M. Rearranged Biosynthetic Gene Cluster and Synthesis of Hassallidin E in Planktothrix serta PCC 8927. ACS Chem Biol 2017; 12:1796-1804. [PMID: 28489343 DOI: 10.1021/acschembio.7b00093] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyanobacteria produce a wide range of natural products with antifungal bioactivity. The cyclic glycosylated lipopeptides of the hassallidin family have potent antifungal activity and display a great degree of chemical diversity. Here, we report the discovery of a hassallidin biosynthetic gene cluster from the filamentous cyanobacterium Planktothrix serta PCC 8927. The hassallidin gene cluster showed heavy rearrangement and marks of genomic plasticity. Nucleotide bias, differences in GC content, and phylogenetic incongruence suggested the acquisition of the hassallidin biosynthetic gene cluster in Planktothrix serta PCC 8927 by horizontal gene transfer. Chemical analyses by liquid chromatography and mass spectrometry demonstrated that this strain produced hassallidin E, a new glycosylated hassallidin variant. Hassallidin E was the only structural variant produced by Planktothrix serta PCC 8927 in all tested conditions. Further evaluated on human pathogenic fungi, hassallidin E showed an antifungal bioactivity. Hassallidin production levels correlated with nitrogen availability, in the only nitrogen-fixing Planktothrix described so far. Our results provide insights into the distribution and chemical diversity of cyanobacterial antifungal compounds as well as raise questions on their ecological relevance.
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Affiliation(s)
- Claire Pancrace
- Institut Pasteur, Collection of Cyanobacteria, Paris, France
- Sorbonne Universités, UPMC Univ Paris 06,
UPEC, UDD, CNRS, INRA, IRD, IEES-Paris, Paris, France
| | - Jouni Jokela
- Microbiology
and Biotechnology Division, Department of Food and Environmental Science, University of Helsinki, Helsinki, Finland
| | | | - Christelle Ganneau
- Institut Pasteur, Unit Chemistry of Biomolecules, Paris, France
- CNRS UMR 3523, Paris, France
| | - Marie Desnos-Ollivier
- Institut Pasteur/CNRS URA3012, National Refence Center
for Invasive Mycoses and Antifungals, Molecular Mycology Unit, Paris, France
| | - Matti Wahlsten
- Microbiology
and Biotechnology Division, Department of Food and Environmental Science, University of Helsinki, Helsinki, Finland
| | - Anu Humisto
- Microbiology
and Biotechnology Division, Department of Food and Environmental Science, University of Helsinki, Helsinki, Finland
| | - Alexandra Calteau
- Commissariat à
l’Energie Atomique et aux Energies Alternatives (CEA), Genoscope/CNRS,
UMR 8030, Laboratoire d’Analyse Bioinformatique en Génomique
et Métabolisme, Evry, France
| | - Sylvie Bay
- Institut Pasteur, Unit Chemistry of Biomolecules, Paris, France
- CNRS UMR 3523, Paris, France
| | - David P. Fewer
- Microbiology
and Biotechnology Division, Department of Food and Environmental Science, University of Helsinki, Helsinki, Finland
| | - Kaarina Sivonen
- Microbiology
and Biotechnology Division, Department of Food and Environmental Science, University of Helsinki, Helsinki, Finland
| | - Muriel Gugger
- Institut Pasteur, Collection of Cyanobacteria, Paris, France
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Spatial and temporal changes of parasitic chytrids of cyanobacteria. Sci Rep 2017; 7:6056. [PMID: 28729657 PMCID: PMC5519717 DOI: 10.1038/s41598-017-06273-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 06/12/2017] [Indexed: 11/15/2022] Open
Abstract
Parasitism is certainly one of the most important driving biotic factors of cyanobacterial blooms which remains largely understudied. Among these parasites, fungi from the phylum Chytridiomycota (i.e. chytrids) are the only eukaryotic microorganisms infecting cyanobacteria. Here, we address spatiotemporal dynamics of the cyanobacterial host Dolichospermum macrosporum (syn. Anabaena macrospora) and its associated chytrid parasites, Rhizosiphon spp., in an eutrophic lake by studying spatial (vertical, horizontal) and temporal (annual and inter-annual) variations. Our results show homogenous chytrid infection patterns along the water column and across sampling stations. However, the prevalence of infection presented drastic changes with time, at both intra- and inter-annual scales. In 2007, a maximum of 98% of vegetative cells were infected by R. crassum whereas this fungal species was not reported seven years later. In opposite, R. akinetum, a chytrid infecting only akinetes, increased its prevalence by 42% during the same period. High chytrid infection rate on the akinetes might have sizeable consequences on host recruitment (and proliferation) success from year to year, as supported by the recorded inter-annual host dynamics (affecting also the success of other chytrid parasites). The spatial homogenous chytrid infection on this cyanobacterium, coupled to both seasonal and inter-annual changes indicates that time, rather than space, controls such highly dynamic host-parasite relationships.
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32
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Frenken T, Alacid E, Berger SA, Bourne EC, Gerphagnon M, Grossart HP, Gsell AS, Ibelings BW, Kagami M, Küpper FC, Letcher PM, Loyau A, Miki T, Nejstgaard JC, Rasconi S, Reñé A, Rohrlack T, Rojas-Jimenez K, Schmeller DS, Scholz B, Seto K, Sime-Ngando T, Sukenik A, Van de Waal DB, Van den Wyngaert S, Van Donk E, Wolinska J, Wurzbacher C, Agha R. Integrating chytrid fungal parasites into plankton ecology: research gaps and needs. Environ Microbiol 2017; 19:3802-3822. [DOI: 10.1111/1462-2920.13827] [Citation(s) in RCA: 120] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 06/09/2017] [Accepted: 06/10/2017] [Indexed: 01/19/2023]
Affiliation(s)
- Thijs Frenken
- Department of Aquatic Ecology; Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10; Wageningen PB 6708 The Netherlands
| | - Elisabet Alacid
- Departament de Biologia Marina i Oceanografia; Institut de Ciències del Mar (CSIC), Pg. Marítim de la Barceloneta, 37-49; Barcelona 08003 Spain
| | - Stella A. Berger
- Department of Experimental Limnology; Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Alte Fischerhuette 2; Stechlin D-16775 Germany
| | - Elizabeth C. Bourne
- Berlin Center for Genomics in Biodiversity Research, Königin-Luise-Straβe 6-8; Berlin D-14195 Germany
- Department of Ecosystem Research; Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301; Berlin 12587 Germany
| | - Mélanie Gerphagnon
- Department of Ecosystem Research; Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301; Berlin 12587 Germany
| | - Hans-Peter Grossart
- Department of Experimental Limnology; Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Alte Fischerhuette 2; Stechlin D-16775 Germany
- Institute for Biochemistry and Biology, Potsdam University, Maulbeerallee 2; Potsdam D-14476 Germany
| | - Alena S. Gsell
- Department of Aquatic Ecology; Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10; Wageningen PB 6708 The Netherlands
| | - Bas W. Ibelings
- Department F.-A. Forel for Environmental and Aquatic Sciences & Institute for Environmental Sciences; University of Geneva, 66 Boulevard Carl Vogt; Geneva 4 CH 1211 Switzerland
| | - Maiko Kagami
- Department of Environmental Sciences, Faculty of Science; Toho University, 2-2-1, Miyama; Funabashi Chiba 274-8510 Japan
| | - Frithjof C. Küpper
- Oceanlab, University of Aberdeen, Main Street; Newburgh Scotland AB41 6AA UK
| | - Peter M. Letcher
- Department of Biological Sciences; The University of Alabama, 300 Hackberry Lane; Tuscaloosa AL 35487 USA
| | - Adeline Loyau
- Department of System Ecotoxicology; Helmholtz Center for Environmental Research - UFZ, Permoserstrasse 15; 04318 Leipzig Germany
- Department of Conservation Biology; Helmholtz Center for Environmental Research - UFZ, Permoserstrasse 15; Leipzig 04318 Germany
- ECOLAB, Université de Toulouse, CNRS, INPT, UPS; Toulouse France
| | - Takeshi Miki
- Institute of Oceanography; National Taiwan University, No.1 Section 4, Roosevelt Road; Taipei 10617 Taiwan
- Research Center for Environmental Changes; Academia Sinica, No.128 Section 2, Academia Road, Nankang; Taipei 11529 Taiwan
| | - Jens C. Nejstgaard
- Department of Experimental Limnology; Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Alte Fischerhuette 2; Stechlin D-16775 Germany
| | - Serena Rasconi
- WasserCluster Lunz - Biological Station; Inter-University Centre for Aquatic Ecosystem Research, A-3293 Lunz am See; Austria
| | - Albert Reñé
- Departament de Biologia Marina i Oceanografia; Institut de Ciències del Mar (CSIC), Pg. Marítim de la Barceloneta, 37-49; Barcelona 08003 Spain
| | - Thomas Rohrlack
- Faculty of Environmental Sciences and Natural Resource Management; Norwegian University of Life Sciences, P.O. Box 5003, NO-1432, Ås; Norway
| | - Keilor Rojas-Jimenez
- Department of Experimental Limnology; Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Alte Fischerhuette 2; Stechlin D-16775 Germany
- Universidad Latina de Costa Rica, Campus San Pedro, Apdo; San Jose 10138-1000 Costa Rica
| | - Dirk S. Schmeller
- Department of Conservation Biology; Helmholtz Center for Environmental Research - UFZ, Permoserstrasse 15; Leipzig 04318 Germany
- ECOLAB, Université de Toulouse, CNRS, INPT, UPS; Toulouse France
| | - Bettina Scholz
- BioPol ehf, Einbúastig 2, Skagaströnd 545; Iceland
- Faculty of Natural Resource Sciences; University of Akureyri, Borgir v. Nordurslod; Akureyri IS 600 Iceland
| | - Kensuke Seto
- Department of Environmental Sciences, Faculty of Science; Toho University, 2-2-1, Miyama; Funabashi Chiba 274-8510 Japan
- Sugadaira Montane Research Center; University of Tsukuba, 1278-294, Sugadaira-Kogen; Ueda, Nagano, 386-2204 Japan
| | - Télesphore Sime-Ngando
- Université Clermont Auvergne, UMR CNRS 6023 LMGE, Laboratoire Microorganismes: Génome et Environnement (LMGE); Campus Universitaire des Cézeaux, Impasse Amélie Murat 1, CS 60026, Aubière, 63178 France
| | - Assaf Sukenik
- Kinneret Limnological Laboratory; Israel Oceanographic & Limnological Research, P.O.Box 447; Migdal, 14950 Israel
| | - Dedmer B. Van de Waal
- Department of Aquatic Ecology; Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10; Wageningen PB 6708 The Netherlands
| | - Silke Van den Wyngaert
- Department of Experimental Limnology; Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Alte Fischerhuette 2; Stechlin D-16775 Germany
| | - Ellen Van Donk
- Department of Aquatic Ecology; Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10; Wageningen PB 6708 The Netherlands
- Department of Biology; University of Utrecht, Padualaan 8; Utrecht TB 3508 The Netherlands
| | - Justyna Wolinska
- Department of Ecosystem Research; Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301; Berlin 12587 Germany
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straβe 1-3; Berlin, 14195 Germany
| | - Christian Wurzbacher
- Department of Biological and Environmental Sciences; University of Gothenburg, Box 461; Göteborg, 405 30 Sweden
- Gothenburg Global Biodiversity Centre, Box 461; Göteborg, SE-405 30 Sweden
| | - Ramsy Agha
- Department of Ecosystem Research; Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301; Berlin 12587 Germany
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Microbial succession dynamics along glacier forefield chronosequences in Tierra del Fuego (Chile). Polar Biol 2017. [DOI: 10.1007/s00300-017-2110-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Legrand B, Lamarque A, Sabart M, Latour D. Characterization of akinetes from cyanobacterial strains and lake sediment: A study of their resistance and toxic potential. HARMFUL ALGAE 2016; 59:42-50. [PMID: 28073505 DOI: 10.1016/j.hal.2016.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 09/13/2016] [Accepted: 09/15/2016] [Indexed: 06/06/2023]
Abstract
Nostocalean cyanobacteria are known to proliferate abundantly in eutrophic aquatic ecosystems, and to produce several cyanotoxins, including anatoxin-a. In this study, we investigated both the resistance and toxic potential of the akinetes (resistant cells), using cyanobacterial cultures and akinetes extracted from the sediment of Lake Aydat (France) sampled in the winter and spring. Intact and lysed akinetes were differentiated using a double control based on the autofluorescence of akinetes and SYTOX-green staining. The percentage of resistant akinetes found in several different abiotic stress conditions was highly variable, depending on the species and also on the sampling season. Thus, the resistance of akinetes and their ability to germinate seems to follow a species-specific process, and akinetes can undergo physiologic changes during the sedimentary phase of the Nostocale life cycle. This study also revealed the first evidence of anatoxin-a genes in akinetes, with anaC and anaF genes detected in akinetes from all cyanobacterial producer cultures. The low number of anaC genes, almost exclusively detected using nested PCR, in the sediment at Lake Aydat suggests a limited but existent past population of toxic Nostocales in this lake. Given the key role of akinetes in the annual cycle and subsequent summer proliferation, it can be interesting to integrate the surveillance of akinetes in the management of lakes exposed to recurrent cyanobacterial blooms.
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Affiliation(s)
- Benjamin Legrand
- Université Clermont Auvergne, Université Blaise Pascal, LMGE, BP 10448, Clermont-Ferrand F-63000, France; CNRS, UMR 6023, LMGE, BP 80026, Aubiere Cedex F-63171, France; Athos-environnement, 112 Avenue du Brézet, Clermont-Ferrand F-63100, France.
| | - Amélie Lamarque
- Université Clermont Auvergne, Université Blaise Pascal, LMGE, BP 10448, Clermont-Ferrand F-63000, France; CNRS, UMR 6023, LMGE, BP 80026, Aubiere Cedex F-63171, France
| | - Marion Sabart
- Université Clermont Auvergne, Université Blaise Pascal, LMGE, BP 10448, Clermont-Ferrand F-63000, France; CNRS, UMR 6023, LMGE, BP 80026, Aubiere Cedex F-63171, France
| | - Delphine Latour
- Université Clermont Auvergne, Université Blaise Pascal, LMGE, BP 10448, Clermont-Ferrand F-63000, France; CNRS, UMR 6023, LMGE, BP 80026, Aubiere Cedex F-63171, France
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Chytrid parasitism facilitates trophic transfer between bloom-forming cyanobacteria and zooplankton (Daphnia). Sci Rep 2016; 6:35039. [PMID: 27733762 PMCID: PMC5062065 DOI: 10.1038/srep35039] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 09/23/2016] [Indexed: 12/05/2022] Open
Abstract
Parasites are rarely included in food web studies, although they can strongly alter trophic interactions. In aquatic ecosystems, poorly grazed cyanobacteria often dominate phytoplankton communities, leading to the decoupling of primary and secondary production. Here, we addressed the interface between predator-prey and host-parasite interactions by conducting a life-table experiment, in which four Daphnia galeata genotypes were maintained on quantitatively comparable diets consisting of healthy cyanobacteria or cyanobacteria infected by a fungal (chytrid) parasite. In four out of five fitness parameters, at least one Daphnia genotype performed better on parasitised cyanobacteria than in the absence of infection. Further treatments consisting of purified chytrid zoospores and heterotrophic bacteria suspensions established the causes of improved fitness. First, Daphnia feed on chytrid zoospores which trophically upgrade cyanobacterial carbon. Second, an increase in heterotrophic bacterial biomass, promoted by cyanobacterial decay, provides an additional food source for Daphnia. In addition, chytrid infection induces fragmentation of cyanobacterial filaments, which could render cyanobacteria more edible. Our results demonstrate that chytrid parasitism can sustain zooplankton under cyanobacterial bloom conditions, and exemplify the potential of parasites to alter interactions between trophic levels.
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Van Wichelen J, Vanormelingen P, Codd GA, Vyverman W. The common bloom-forming cyanobacterium Microcystis is prone to a wide array of microbial antagonists. HARMFUL ALGAE 2016; 55:97-111. [PMID: 28073551 DOI: 10.1016/j.hal.2016.02.009] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/18/2016] [Accepted: 02/19/2016] [Indexed: 06/06/2023]
Abstract
Many degraded waterbodies around the world are subject to strong proliferations of cyanobacteria - notorious for their toxicity, high biomass build-up and negative impacts on aquatic food webs - the presence of which puts serious limits on the human use of affected water bodies. Cyanobacterial blooms are largely regarded as trophic dead ends since they are a relatively poor food source for zooplankton. As a consequence, their population dynamics are generally attributed to changes in abiotic conditions (bottom-up control). Blooms however generally contain a vast and diverse community of micro-organisms of which some have shown devastating effects on cyanobacterial biomass. For Microcystis, one of the most common bloom-forming cyanobacteria worldwide, a high number of micro-organisms (about 120 taxa) including viruses, bacteria, microfungi, different groups of heterotrophic protists, other cyanobacteria and several eukaryotic microalgal groups are currently known to negatively affect its growth by infection and predation or by the production of allelopathic compounds. Although many of these specifically target Microcystis, sharp declines of Microcystis biomass in nature are only rarely assigned to these antagonistic microbiota. The commonly found strain specificity of their interactions may largely preclude strong antagonistic effects on Microcystis population levels but may however induce compositional shifts that can change ecological properties such as bloom toxicity. These highly specific interactions may form the basis of a continuous arms race (co-evolution) between Microcystis and its antagonists which potentially limits the possibilities for (micro)biological bloom control.
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Affiliation(s)
- Jeroen Van Wichelen
- Protistology and Aquatic Ecology, Biology Department, Ghent University, Krijgslaan 281 (S8), 9000 Gent, Belgium.
| | - Pieter Vanormelingen
- Protistology and Aquatic Ecology, Biology Department, Ghent University, Krijgslaan 281 (S8), 9000 Gent, Belgium
| | - Geoffrey A Codd
- Biological and Environmental Sciences, School of Natural Sciences, University of Stirling, Stirling FK9 4LA, Scotland, UK
| | - Wim Vyverman
- Protistology and Aquatic Ecology, Biology Department, Ghent University, Krijgslaan 281 (S8), 9000 Gent, Belgium
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Jeffries TC, Curlevski NJ, Brown MV, Harrison DP, Doblin MA, Petrou K, Ralph PJ, Seymour JR. Partitioning of fungal assemblages across different marine habitats. ENVIRONMENTAL MICROBIOLOGY REPORTS 2016; 8:235-238. [PMID: 26742806 DOI: 10.1111/1758-2229.12373] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 12/17/2015] [Accepted: 12/21/2015] [Indexed: 06/05/2023]
Abstract
Fungi are a highly diverse group of microbes that fundamentally influence the biogeochemistry of the biosphere, but we currently know little about the diversity and distribution of fungi in aquatic habitats. Here we describe shifts in marine fungal community composition across different marine habitats, using targeted pyrosequencing of the fungal Internal Transcribed Spacer (ITS) region. Our results demonstrate strong partitioning of fungal community composition between estuarine, coastal and oceanic samples, with each habitat hosting discrete communities that are controlled by patterns in salinity, temperature, oxygen and nutrients. Whereas estuarine habitats comprised a significant proportion of fungal groups often found in terrestrial habitats, the open ocean sites were dominated by previously unidentified groups. The patterns observed here indicate that fungi are potentially a significant, although largely overlooked, feature of the ocean's microbiota, but greater efforts to characterize marine species are required before the full ecological and biogeochemical importance of marine fungi can be ascertained.
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Affiliation(s)
- Thomas Charles Jeffries
- Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Sydney, NSW, Australia
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Nathalie J Curlevski
- Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Sydney, NSW, Australia
| | - Mark Vincent Brown
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Daniel P Harrison
- University of Sydney Institute of Marine Science, School of Geosciences, University of Sydney, Sydney, NSW, Australia
- Sydney Institute of Marine Science, Mosman, NSW, Australia
| | - Martina A Doblin
- Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Sydney, NSW, Australia
| | - Katherina Petrou
- Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Sydney, NSW, Australia
| | - Peter J Ralph
- Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Sydney, NSW, Australia
| | - Justin R Seymour
- Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Sydney, NSW, Australia
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Gutiérrez MH, Jara AM, Pantoja S. Fungal parasites infect marine diatoms in the upwelling ecosystem of the Humboldt current system off central Chile. Environ Microbiol 2016; 18:1646-53. [DOI: 10.1111/1462-2920.13257] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 02/08/2016] [Indexed: 11/27/2022]
Affiliation(s)
- Marcelo H. Gutiérrez
- Marine Organic Geochemistry Laboratory, Department of Oceanography; Universidad de Concepción; Chile
- COPAS Sur-Austral, Universidad de Concepción; Chile
| | - Ana M. Jara
- Marine Organic Geochemistry Laboratory, Department of Oceanography; Universidad de Concepción; Chile
| | - Silvio Pantoja
- Marine Organic Geochemistry Laboratory, Department of Oceanography; Universidad de Concepción; Chile
- COPAS Sur-Austral, Universidad de Concepción; Chile
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Grossart HP, Wurzbacher C, James TY, Kagami M. Discovery of dark matter fungi in aquatic ecosystems demands a reappraisal of the phylogeny and ecology of zoosporic fungi. FUNGAL ECOL 2016. [DOI: 10.1016/j.funeco.2015.06.004] [Citation(s) in RCA: 139] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Environmental Conditions Determine the Course and Outcome of Phytoplankton Chytridiomycosis. PLoS One 2015; 10:e0145559. [PMID: 26714010 PMCID: PMC4703133 DOI: 10.1371/journal.pone.0145559] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 12/04/2015] [Indexed: 11/29/2022] Open
Abstract
Chytrid fungi are highly potent parasites of phytoplankton. They are thought to force phytoplankton organisms into an evolutionary arms race with high population diversity as the outcome. The underlying selection regime is known as Red Queen dynamics. However, our study suggests a more complex picture for chytrid parasitism in the cyanobacterium Planktothrix. Laboratory experiments identified a “cold thermal refuge”, inside which Planktothrix can grow without chytrid infection. A field study in two Norwegian lakes underlined the ecological significance of this finding. The study utilized sediment DNA as a biological archive in combination with existing monitoring data. In one lake, temperature and light conditions forced Planktothrix outside the thermal refuge for most of the growing season. This probably resulted in Red Queen dynamics as suggested by a high parasitic pressure exerted by chytrids, an increase in Planktothrix genotype diversity over time, and a correlation between Planktothrix genotype diversity and duration of bloom events. In the second lake, a colder climate allowed Planktothrix to largely stay inside the thermal refuge. The parasitic pressure exerted by chytrids and Planktothrix genotype diversity remained low, indicating that Planktothrix successfully evaded the Red Queen dynamics. Episodic Planktothrix blooms were observed during spring and autumn circulation, in the metalimnion or under the ice. Interestingly, both lakes were dominated by the same or related Planktothrix genotypes. Taken together, our data suggest that, depending on environmental conditions, chytrid parasitism can impose distinct selection regimes on conspecific phytoplankton populations with similar genotype composition, causing these populations to behave and perhaps to evolve differently.
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Tan B, Ng C, Nshimyimana JP, Loh LL, Gin KYH, Thompson JR. Next-generation sequencing (NGS) for assessment of microbial water quality: current progress, challenges, and future opportunities. Front Microbiol 2015; 6:1027. [PMID: 26441948 PMCID: PMC4585245 DOI: 10.3389/fmicb.2015.01027] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 09/10/2015] [Indexed: 12/20/2022] Open
Abstract
Water quality is an emergent property of a complex system comprised of interacting microbial populations and introduced microbial and chemical contaminants. Studies leveraging next-generation sequencing (NGS) technologies are providing new insights into the ecology of microbially mediated processes that influence fresh water quality such as algal blooms, contaminant biodegradation, and pathogen dissemination. In addition, sequencing methods targeting small subunit (SSU) rRNA hypervariable regions have allowed identification of signature microbial species that serve as bioindicators for sewage contamination in these environments. Beyond amplicon sequencing, metagenomic and metatranscriptomic analyses of microbial communities in fresh water environments reveal the genetic capabilities and interplay of waterborne microorganisms, shedding light on the mechanisms for production and biodegradation of toxins and other contaminants. This review discusses the challenges and benefits of applying NGS-based methods to water quality research and assessment. We will consider the suitability and biases inherent in the application of NGS as a screening tool for assessment of biological risks and discuss the potential and limitations for direct quantitative interpretation of NGS data. Secondly, we will examine case studies from recent literature where NGS based methods have been applied to topics in water quality assessment, including development of bioindicators for sewage pollution and microbial source tracking, characterizing the distribution of toxin and antibiotic resistance genes in water samples, and investigating mechanisms of biodegradation of harmful pollutants that threaten water quality. Finally, we provide a short review of emerging NGS platforms and their potential applications to the next generation of water quality assessment tools.
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Affiliation(s)
- BoonFei Tan
- Center for Environmental Sensing and Modelling, Singapore-MIT Alliance for Research and Technology CentreSingapore, Singapore
| | - Charmaine Ng
- Department of Civil and Environmental Engineering, National University of SingaporeSingapore, Singapore
| | - Jean Pierre Nshimyimana
- Center for Environmental Sensing and Modelling, Singapore-MIT Alliance for Research and Technology CentreSingapore, Singapore
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological UniversitySingapore, Singapore
- School of Civil and Environmental Engineering, Nanyang Technological UniversitySingapore, Singapore
| | - Lay Leng Loh
- Center for Environmental Sensing and Modelling, Singapore-MIT Alliance for Research and Technology CentreSingapore, Singapore
- Department of Civil and Environmental Engineering, National University of SingaporeSingapore, Singapore
| | - Karina Y.-H. Gin
- Department of Civil and Environmental Engineering, National University of SingaporeSingapore, Singapore
| | - Janelle R. Thompson
- Center for Environmental Sensing and Modelling, Singapore-MIT Alliance for Research and Technology CentreSingapore, Singapore
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, CambridgeMA, USA
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Sabart M, Crenn K, Perrière F, Abila A, Leremboure M, Colombet J, Jousse C, Latour D. Co-occurrence of microcystin and anatoxin-a in the freshwater lake Aydat (France): Analytical and molecular approaches during a three-year survey. HARMFUL ALGAE 2015; 48:12-20. [PMID: 29724471 DOI: 10.1016/j.hal.2015.06.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 06/15/2015] [Accepted: 06/15/2015] [Indexed: 06/08/2023]
Abstract
Cyanobacterial mass occurrence is becoming a growing concern worldwide. They notably pose a threat to water users when cyanotoxins are produced. The aim of this study was to evaluate the occurrence and the dynamics of two cyanotoxins: microcystin (MC) and anatoxin-a (ANTX-a), and of two of the genes responsible for their production (respectively mcyA and anaC) during three consecutive bloom periods (2011, 2012 and 2013) in Lake Aydat (Auvergne, France). MC was detected at all sampling dates, but its concentration showed strong inter- and intra-annual variations. MC content did not correlate with cyanobacterial abundance, nor with any genera taken individually, but it significantly correlated with mcyA gene abundance (R2=0.51; p=0.042). MC content and mcyA gene abundance were maximal when cyanobacterial abundance was low, either at the onset of the bloom or during a trough of biomass. The LC-MS/MS analysis showed the presence of ANTX-a in the 2011 samples. To our knowledge, this is the first report of the presence of this neurotoxin in a French lake. The presence of ANTX-a corresponded to the only year for which Anabaena did not dominate the cyanobacterial community alone, and several cyanobacterial genera were present, including notably Aphanizomenon. anaC gene detection by PCR was not coherent with ANTX-a presence, both gene and toxin were never found for a same sample. This implies that molecular tools to study genes responsible for the production of anatoxin-a are still imperfect and the development of new primers is needed. This study also highlights the need for better monitoring practices that would not necessarily focus only on the peak of cyanobacterial abundance and that would take cyanotoxins other than MC into account.
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Affiliation(s)
- Marion Sabart
- Université Clermont Auvergne, Université Blaise Pascal, LMGE, BP 10448, Clermont-Ferrand, F-63000, France; CNRS, UMR 6023, LMGE, BP 80026, Aubiere Cedex, F-63171, France.
| | - Kristell Crenn
- Université Clermont Auvergne, Université Blaise Pascal, LMGE, BP 10448, Clermont-Ferrand, F-63000, France; CNRS, UMR 6023, LMGE, BP 80026, Aubiere Cedex, F-63171, France
| | - Fanny Perrière
- Université Clermont Auvergne, Université Blaise Pascal, LMGE, BP 10448, Clermont-Ferrand, F-63000, France; CNRS, UMR 6023, LMGE, BP 80026, Aubiere Cedex, F-63171, France
| | - Angélique Abila
- Université Clermont Auvergne, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand (ICCF) and Mass Spectrometry Facility (UBP-START), BP 10448, Clermont-Ferrand, F-63000 FRANCE; CNRS, UMR 6296, ICCF, F-63171 Aubiere, FRANCE
| | - Martin Leremboure
- Université Clermont Auvergne, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand (ICCF) and Mass Spectrometry Facility (UBP-START), BP 10448, Clermont-Ferrand, F-63000 FRANCE; CNRS, UMR 6296, ICCF, F-63171 Aubiere, FRANCE
| | - Jonathan Colombet
- Université Clermont Auvergne, Université Blaise Pascal, LMGE, BP 10448, Clermont-Ferrand, F-63000, France; CNRS, UMR 6023, LMGE, BP 80026, Aubiere Cedex, F-63171, France
| | - Cyril Jousse
- Université Clermont Auvergne, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand (ICCF) and Mass Spectrometry Facility (UBP-START), BP 10448, Clermont-Ferrand, F-63000 FRANCE; CNRS, UMR 6296, ICCF, F-63171 Aubiere, FRANCE
| | - Delphine Latour
- Université Clermont Auvergne, Université Blaise Pascal, LMGE, BP 10448, Clermont-Ferrand, F-63000, France; CNRS, UMR 6023, LMGE, BP 80026, Aubiere Cedex, F-63171, France
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43
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Gerphagnon M, Macarthur DJ, Latour D, Gachon CMM, Van Ogtrop F, Gleason FH, Sime-Ngando T. Microbial players involved in the decline of filamentous and colonial cyanobacterial blooms with a focus on fungal parasitism. Environ Microbiol 2015; 17:2573-87. [DOI: 10.1111/1462-2920.12860] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 03/01/2015] [Accepted: 03/05/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Mélanie Gerphagnon
- LMGE; Laboratoire Microorganismes: Génome et Environnement; UMR CNRS 6023; Clermont Université; Université Blaise Pascal; BP 80026 Aubière CEDEX 63171 France
- Culture Collection for Algae and Protozoa; Scottish Marine Institute; Scottish Association for Marine Science; Oban PA37 1QA UK
| | | | - Delphine Latour
- LMGE; Laboratoire Microorganismes: Génome et Environnement; UMR CNRS 6023; Clermont Université; Université Blaise Pascal; BP 80026 Aubière CEDEX 63171 France
| | - Claire M. M. Gachon
- Culture Collection for Algae and Protozoa; Scottish Marine Institute; Scottish Association for Marine Science; Oban PA37 1QA UK
| | - Floris Van Ogtrop
- School of Biological Sciences; University of Sydney; Sydney Australia
| | - Frank H. Gleason
- School of Biological Sciences; University of Sydney; Sydney Australia
| | - Télesphore Sime-Ngando
- LMGE; Laboratoire Microorganismes: Génome et Environnement; UMR CNRS 6023; Clermont Université; Université Blaise Pascal; BP 80026 Aubière CEDEX 63171 France
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44
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Gleason FH, Jephcott TG, Küpper FC, Gerphagnon M, Sime-Ngando T, Karpov SA, Guillou L, van Ogtrop FF. Potential roles for recently discovered chytrid parasites in the dynamics of harmful algal blooms. FUNGAL BIOL REV 2015. [DOI: 10.1016/j.fbr.2015.03.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Carreira C, Staal M, Falkoski D, de Vries RP, Middelboe M, Brussaard CPD. Disruption of photoautotrophic intertidal mats by filamentous fungi. Environ Microbiol 2015; 17:2910-21. [PMID: 25728280 DOI: 10.1111/1462-2920.12835] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 02/17/2015] [Accepted: 02/23/2015] [Indexed: 11/28/2022]
Abstract
Ring-like structures, 2.0-4.8 cm in diameter, observed in photosynthetic microbial mats on the Wadden Sea island Schiermonnikoog (the Netherlands) showed to be the result of the fungus Emericellopsis sp. degrading the photoautotrophic top layer of the mat. The mats were predominantly composed of cyanobacteria and diatoms, with large densities of bacteria and viruses both in the top photosynthetic layer and in the underlying sediment. The fungal attack cleared the photosynthetic layer; however, no significant effect of the fungal lysis on the bacterial and viral abundances could be detected. Fungal-mediated degradation of the major photoautotrophs could be reproduced by inoculation of non-infected mat with isolated Emericellopsis sp., and with an infected ring sector. Diatoms were the first re-colonizers followed closely by cyanobacteria that after about 5 days dominated the space. The study demonstrated that the fungus Emericellopsis sp. efficiently degraded a photoautotrophic microbial mat, with potential implications for mat community composition, spatial structure and productivity.
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Affiliation(s)
- Cátia Carreira
- Department of Biological Oceanography, Royal Netherlands Institute for Sea Research (NIOZ), 8 PO Box 50, NL, 1790 AB, Den Burg, The Netherlands.,Section for Marine Biology, University of Copenhagen, Strandpromenaden 5, 3000, Helsingør, Denmark
| | - Marc Staal
- Section for Marine Biology, University of Copenhagen, Strandpromenaden 5, 3000, Helsingør, Denmark
| | - Daniel Falkoski
- Fungal Physiology, CBS-KNAW Fungal Biodiversity Centre, Utrecht, The Netherlands
| | - Ronald P de Vries
- Fungal Physiology, CBS-KNAW Fungal Biodiversity Centre, Utrecht, The Netherlands.,Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands
| | - Mathias Middelboe
- Section for Marine Biology, University of Copenhagen, Strandpromenaden 5, 3000, Helsingør, Denmark
| | - Corina P D Brussaard
- Department of Biological Oceanography, Royal Netherlands Institute for Sea Research (NIOZ), 8 PO Box 50, NL, 1790 AB, Den Burg, The Netherlands.,Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
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46
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Kyle M, Haande S, Ostermaier V, Rohrlack T. The Red Queen race between parasitic chytrids and their host, Planktothrix: a test using a time series reconstructed from sediment DNA. PLoS One 2015; 10:e0118738. [PMID: 25793898 PMCID: PMC4368186 DOI: 10.1371/journal.pone.0118738] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 01/07/2015] [Indexed: 11/19/2022] Open
Abstract
Parasitic chytrid fungi (phylum Chytridiomycota) are known to infect specific phytoplankton, including the filamentous cyanobacterium Planktothrix. Subspecies, or chemotypes of Planktothrix can be identified by the presence of characteristic oligopeptides. Some of these oligopeptides can be associated with important health concerns due to their potential for toxin production. However, the relationship between chytrid parasite and Planktothrix host is not clearly understood and more research is needed. To test the parasite-host relationship over time, we used a sediment core extracted from a Norwegian lake known to contain both multiple Planktothrix chemotype hosts and their parasitic chytrid. Sediment DNA of chytrids and Planktothrix was amplified and a 35-year coexistence was found. It is important to understand how these two antagonistic species can coexistence in a lake. Reconstruction of the time series showed that between 1979-1990 at least 2 strains of Planktothrix were present and parasitic pressure exerted by chytrids was low. After this period one chemotype became dominant and yet showed continued low susceptibility to chytrid parasitism. Either environmental conditions or intrinsic characteristics of Planktothrix could have been responsible for this continued dominance. One possible explanation could be found in the shift of Planktothrix to the metalimnion, an environment that typically consists of low light and decreased temperatures. Planktothrix are capable of growth under these conditions while the chytrid parasites are constrained. Another potential explanation could be due to the differences between cellular oligopeptide variations found between Planktothrix chemotypes. These oligopeptides can function as defense systems against chytrids. Our findings suggest that chytrid driven diversity was not maintained over time, but that the combination of environmental constraints and multiple oligopeptide production to combat chytrids could have allowed one Planktothrix chemotype to have dominance despite chytrid presence.
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Affiliation(s)
- Marcia Kyle
- Norwegian University of Life Sciences (NMBU), Environmental Sciences, Ås, Norway
| | - Sigrid Haande
- Norwegian Institute for Water Research (NIVA), Oslo, Norway
| | | | - Thomas Rohrlack
- Norwegian University of Life Sciences (NMBU), Environmental Sciences, Ås, Norway
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Rasconi S, Grami B, Niquil N, Jobard M, Sime-Ngando T. Parasitic chytrids sustain zooplankton growth during inedible algal bloom. Front Microbiol 2014; 5:229. [PMID: 24904543 PMCID: PMC4033230 DOI: 10.3389/fmicb.2014.00229] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 04/29/2014] [Indexed: 11/13/2022] Open
Abstract
This study assesses the quantitative impact of parasitic chytrids on the planktonic food web of two contrasting freshwater lakes during different algal bloom situations. Carbon-based food web models were used to investigate the effects of chytrids during the spring diatom bloom in Lake Pavin (oligo-mesotrophic) and the autumn cyanobacteria bloom in Lake Aydat (eutrophic). Linear inverse modeling was employed to estimate undetermined flows in both lakes. The Monte Carlo Markov chain linear inverse modeling procedure provided estimates of the ranges of model-derived fluxes. Model results confirm recent theories on the impact of parasites on food web function through grazers and recyclers. During blooms of "inedible" algae (unexploited by planktonic herbivores), the epidemic growth of chytrids channeled 19-20% of the primary production in both lakes through the production of grazer exploitable zoospores. The parasitic throughput represented 50% and 57% of the zooplankton diet, respectively, in the oligo-mesotrophic and in the eutrophic lakes. Parasites also affected ecological network properties such as longer carbon path lengths and loop strength, and contributed to increase the stability of the aquatic food web, notably in the oligo-mesotrophic Lake Pavin.
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Affiliation(s)
- Serena Rasconi
- CNRS UMR 6250, UMRi 7266, LIENSs, Université de La Rochelle La Rochelle, France
| | - Boutheina Grami
- CNRS UMR 6250, UMRi 7266, LIENSs, Université de La Rochelle La Rochelle, France
| | - Nathalie Niquil
- CNRS UMR 6250, UMRi 7266, LIENSs, Université de La Rochelle La Rochelle, France
| | - Marlène Jobard
- CNRS UMR 6023, LMGE, Clermont Université Aubière Cedex, France
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A double staining method using SYTOX green and calcofluor white for studying fungal parasites of phytoplankton. Appl Environ Microbiol 2013; 79:3943-51. [PMID: 23603679 DOI: 10.1128/aem.00696-13] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We propose a double staining method based on the combination of two fluorochromes, calcofluor white (CFW; specific chitinous fluorochrome) and SYTOX green (nucleic acid stain), coupled to epifluorescence microscopy for counting, identifying, and investigating the fecundity of parasitic fungi of phytoplankton and the putative relationships established between hosts and their chytrid parasites. The method was applied to freshwater samples collected over two successive years during the terminal period of autumnal cyanobacterial blooms in a eutrophic lake. The study focused on the uncultured host-parasite couple Anabaena macrospora (cyanobacterium) and Rhizosiphon akinetum (Chytridiomycota). Our results showed that up to 36.6% of cyanobacterial akinetes could be parasitized by fungi. Simultaneously, we directly investigated the zoosporic content inside the sporangia and found that both the host size and intensity of infection conditioned the final size and hence fecundity of the chytrids. We found that relationships linking host size, final parasite size, and chytrid fecundity were conserved from year to year and seemed to be host-chytrid couple specific. We concluded that our double staining method was a valid procedure for improving our knowledge of uncultured freshwater phytoplankton-chytrid couples and so of the quantitative ecology of chytrids in freshwater ecosystems.
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