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Krinos AI, Bowers RM, Rohwer RR, McMahon KD, Woyke T, Schulz F. Time-series metagenomics reveals changing protistan ecology of a temperate dimictic lake. MICROBIOME 2024; 12:133. [PMID: 39030632 PMCID: PMC11265017 DOI: 10.1186/s40168-024-01831-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Accepted: 05/06/2024] [Indexed: 07/21/2024]
Abstract
BACKGROUND Protists, single-celled eukaryotic organisms, are critical to food web ecology, contributing to primary productivity and connecting small bacteria and archaea to higher trophic levels. Lake Mendota is a large, eutrophic natural lake that is a Long-Term Ecological Research site and among the world's best-studied freshwater systems. Metagenomic samples have been collected and shotgun sequenced from Lake Mendota for the last 20 years. Here, we analyze this comprehensive time series to infer changes to the structure and function of the protistan community and to hypothesize about their interactions with bacteria. RESULTS Based on small subunit rRNA genes extracted from the metagenomes and metagenome-assembled genomes of microeukaryotes, we identify shifts in the eukaryotic phytoplankton community over time, which we predict to be a consequence of reduced zooplankton grazing pressures after the invasion of a invasive predator (the spiny water flea) to the lake. The metagenomic data also reveal the presence of the spiny water flea and the zebra mussel, a second invasive species to Lake Mendota, prior to their visual identification during routine monitoring. Furthermore, we use species co-occurrence and co-abundance analysis to connect the protistan community with bacterial taxa. Correlation analysis suggests that protists and bacteria may interact or respond similarly to environmental conditions. Cryptophytes declined in the second decade of the timeseries, while many alveolate groups (e.g., ciliates and dinoflagellates) and diatoms increased in abundance, changes that have implications for food web efficiency in Lake Mendota. CONCLUSIONS We demonstrate that metagenomic sequence-based community analysis can complement existing efforts to monitor protists in Lake Mendota based on microscopy-based count surveys. We observed patterns of seasonal abundance in microeukaryotes in Lake Mendota that corroborated expectations from other systems, including high abundance of cryptophytes in winter and diatoms in fall and spring, but with much higher resolution than previous surveys. Our study identified long-term changes in the abundance of eukaryotic microbes and provided context for the known establishment of an invasive species that catalyzes a trophic cascade involving protists. Our findings are important for decoding potential long-term consequences of human interventions, including invasive species introduction. Video Abstract.
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Affiliation(s)
- Arianna I Krinos
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
- Department of Earth, Atmospheric, and Planetary Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
- MIT-WHOI Joint Program in Oceanography/Applied Ocean Science and Engineering, Cambridge, Woods Hole, MA, USA.
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Robert M Bowers
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Robin R Rohwer
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | - Katherine D McMahon
- Department of Bacteriology, University of Wisconsin at Madison, Madison, WI, USA
| | - Tanja Woyke
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Frederik Schulz
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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Martens N, Russnak V, Woodhouse J, Grossart HP, Schaum CE. Metabarcoding reveals potentially mixotrophic flagellates and picophytoplankton as key groups of phytoplankton in the Elbe estuary. ENVIRONMENTAL RESEARCH 2024; 252:119126. [PMID: 38734293 DOI: 10.1016/j.envres.2024.119126] [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: 02/20/2024] [Revised: 05/07/2024] [Accepted: 05/09/2024] [Indexed: 05/13/2024]
Abstract
In estuaries, phytoplankton are faced with strong environmental forcing (e.g. high turbidity, salinity gradients). Taxa that appear under such conditions may play a critical role in maintaining food webs and biological carbon pumping, but knowledge about estuarine biota remains limited. This is also the case in the Elbe estuary where the lower 70 km of the water body are largely unexplored. In the present study, we investigated the phytoplankton composition in the Elbe estuary via metabarcoding. Our aim was to identify key taxa in the unmonitored reaches of this ecosystem and compare our results from the monitored area with available microscopy data. Phytoplankton communities followed distinct seasonal and spatial patterns. Community composition was similar across methods. Contributions of key classes and genera were correlated to each other (p < 0.05) when obtained from reads and biovolume (R2 = 0.59 and 0.33, respectively). Centric diatoms (e.g. Stephanodiscus) were the dominant group - comprising on average 55 % of the reads and 66-69 % of the biovolume. However, results from metabarcoding imply that microscopy underestimates the prevalence of picophytoplankton and flagellates with a potential for mixotrophy (e.g. cryptophytes). This might be due to their small size and sensitivity to fixation agents. We argue that mixotrophic flagellates are ecologically relevant in the mid to lower estuary, where, e.g., high turbidity render living conditions rather unfavorable, and skills such as phagotrophy provide fundamental advantages. Nevertheless, further findings - e.g. important taxa missing from the metabarcoding dataset - emphasize potential limitations of this method and quantitative biases can result from varying numbers of gene copies in different taxa. Further research should address these methodological issues but also shed light on the causal relationship of taxa with the environmental conditions, also with respect to active mixotrophic behavior.
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Affiliation(s)
- Nele Martens
- Institute of Marine Ecosystem and Fishery Science, Olbersweg 24, 22767, Hamburg, Germany.
| | - Vanessa Russnak
- Helmholtz-Zentrum hereon, Max-Planck-Straße 1, 21502, Geesthacht, Germany.
| | - Jason Woodhouse
- Institute of Cell and Systems Biology of Animals, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany.
| | - Hans-Peter Grossart
- Leibniz Institute of Freshwater Ecology and Inland Fisheries, Alte Fischerhütte 2, 16775, Stechlin, Germany; Institute of Biochemistry and Biology, Maulbeerallee 2, 14469, Potsdam, Germany.
| | - C-Elisa Schaum
- Institute of Marine Ecosystem and Fishery Science, Olbersweg 24, 22767, Hamburg, Germany; Center for Earth System Research and Sustainability, Bundesstraße 53-55, 20146, Hamburg, Germany.
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3
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Muñoz-Marín MDC, López-Lozano A, Moreno-Cabezuelo JÁ, Díez J, García-Fernández JM. Mixotrophy in cyanobacteria. Curr Opin Microbiol 2024; 78:102432. [PMID: 38325247 DOI: 10.1016/j.mib.2024.102432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 12/22/2023] [Accepted: 01/10/2024] [Indexed: 02/09/2024]
Abstract
Cyanobacteria evolved the oxygenic photosynthesis to generate organic matter from CO2 and sunlight, and they were responsible for the production of oxygen in the Earth's atmosphere. This made them a model for photosynthetic organisms, since they are easier to study than higher plants. Early studies suggested that only a minority among cyanobacteria might assimilate organic compounds, being considered mostly autotrophic for decades. However, compelling evidence from marine and freshwater cyanobacteria, including toxic strains, in the laboratory and in the field, has been obtained in the last decades: by using physiological and omics approaches, mixotrophy has been found to be a more widespread feature than initially believed. Furthermore, dominant clades of marine cyanobacteria can take up organic compounds, and mixotrophy is critical for their survival in deep waters with very low light. Hence, mixotrophy seems to be an essential trait in the metabolism of most cyanobacteria, which can be exploited for biotechnological purposes.
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Affiliation(s)
- María Del Carmen Muñoz-Marín
- Departamento de Bioquímica y Biología Molecular, Campus de Excelencia Universitario ceiA3, Universidad de Córdoba, Edificio Severo Ochoa, planta 1, ala Este, Campus de Rabanales, 14071 Córdoba, Spain
| | - Antonio López-Lozano
- Departamento de Bioquímica y Biología Molecular, Campus de Excelencia Universitario ceiA3, Universidad de Córdoba, Edificio Severo Ochoa, planta 1, ala Este, Campus de Rabanales, 14071 Córdoba, Spain
| | - José Ángel Moreno-Cabezuelo
- Departamento de Bioquímica y Biología Molecular, Campus de Excelencia Universitario ceiA3, Universidad de Córdoba, Edificio Severo Ochoa, planta 1, ala Este, Campus de Rabanales, 14071 Córdoba, Spain
| | - Jesús Díez
- Departamento de Bioquímica y Biología Molecular, Campus de Excelencia Universitario ceiA3, Universidad de Córdoba, Edificio Severo Ochoa, planta 1, ala Este, Campus de Rabanales, 14071 Córdoba, Spain.
| | - José Manuel García-Fernández
- Departamento de Bioquímica y Biología Molecular, Campus de Excelencia Universitario ceiA3, Universidad de Córdoba, Edificio Severo Ochoa, planta 1, ala Este, Campus de Rabanales, 14071 Córdoba, Spain.
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4
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Martens N, Ehlert E, Putri W, Sibbertsen M, Schaum CE. Organic compounds drive growth in phytoplankton taxa from different functional groups. Proc Biol Sci 2024; 291:20232713. [PMID: 38320614 PMCID: PMC10846936 DOI: 10.1098/rspb.2023.2713] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 01/12/2024] [Indexed: 02/08/2024] Open
Abstract
Phytoplankton are usually considered autotrophs, but an increasing number of studies show that many taxa are able also to use organic carbon. Acquiring nutrients and energy from different sources might enable an efficient uptake of required substances and provide a strategy to deal with varying resource availability, especially in highly dynamic ecosystems such as estuaries. In our study, we investigated the effects of 31 organic carbon sources on the growth (proxied by differences in cell counts after 24 h exposure) of 17 phytoplankton strains from the Elbe estuary spanning four functional groups. All of our strains were able to make use of at least 1 and up to 26 organic compounds for growth. Pico-sized green algae such as Mychonastes, as well as the nano-sized green alga Monoraphidium in particular were positively affected by a high variety of substances. Reduced light availability, typically appearing in turbid estuaries and similar habitats, resulted in an overall poorer ability to use organic substances for growth, indicating that organic carbon acquisition was not primarily a strategy to deal with darkness. Our results give further evidence for mixotrophy being a ubiquitous ability of phytoplankton and highlight the importance to consider this trophic strategy in research.
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Affiliation(s)
- Nele Martens
- Institute of Marine Ecosystem and Fishery Science, Olbersweg 24, 22767 Hamburg, Germany
| | - Emilia Ehlert
- Institute of Marine Ecosystem and Fishery Science, Olbersweg 24, 22767 Hamburg, Germany
| | - Widhi Putri
- Institute of Marine Ecosystem and Fishery Science, Olbersweg 24, 22767 Hamburg, Germany
| | - Martje Sibbertsen
- Institute of Marine Ecosystem and Fishery Science, Olbersweg 24, 22767 Hamburg, Germany
| | - C.-Elisa Schaum
- Institute of Marine Ecosystem and Fishery Science, Olbersweg 24, 22767 Hamburg, Germany
- Center for Earth System Research and Sustainability, Bundesstraße 53–55, 20146 Hamburg, Germany
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Costa MRA, Cardoso MML, Selmeczy GB, Padisák J, Becker V. Phytoplankton functional responses induced by extreme hydrological events in a tropical reservoir. HYDROBIOLOGIA 2023:1-19. [PMID: 37363742 PMCID: PMC10184627 DOI: 10.1007/s10750-023-05241-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 04/12/2023] [Accepted: 04/24/2023] [Indexed: 06/28/2023]
Abstract
Climate change is affecting the global hydrological cycle, causing drastic changes in precipitation patterns. Extreme climatic events are becoming more frequent and intense than in the past, leading to water-level fluctuations and affecting aquatic ecosystems. Semiarid regions are very susceptible to changing climate. We analyzed a 10 years dataset from a tropical semiarid reservoir during extreme hydrological events (heavy rains and prolonged drought), and evaluated phytoplankton functional responses to environmental conditions. We found, as hypothesized, that phytoplankton functional structure change in a temporal scale due to water-volume fluctuation induced by the rainfall pattern. Depth and inorganic material acted as environmental filters selecting phytoplankton groups. High water level seems to improve water quality and low water level worsen it. Colonial and filamentous cyanobacteria dominate the wet period; however, it may have a critical threshold during severe periods of drought, which will lead to dominance of groups well adapted to low light conditions and with mixotrophic metabolism. Phytoplankton functional approaches can simplify phytoplankton identification and reflect better the environmental conditions than the taxonomic approach. Therefore, these approaches can help to understand the shifts in aquatic ecosystems under extreme hydrological events and predict functional response of phytoplankton being an important tool to water management and conservation. Supplementary Information The online version contains supplementary material available at 10.1007/s10750-023-05241-3.
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Affiliation(s)
- Mariana R. A. Costa
- ELKH-PE Limnoecology Research Group, Egyetem u. 10, Veszprém, 8200 Hungary
- Programa de Pós-Graduação em Ecologia, Departamento de Ecologia, Universidade Federal do Rio Grande do Norte, Av. Senador Salgado Filho 3000, Natal, RN Brazil
| | - Maria M. L. Cardoso
- Secretaria da Educação da Ciência e Tecnologia do Estado da Paraíba, Avenida Dr. João da Mata, nº 200, Jaguaribe, João Pessoa, PB Brasil
| | - Géza B. Selmeczy
- ELKH-PE Limnoecology Research Group, Egyetem u. 10, Veszprém, 8200 Hungary
- University of Pannonia, Center of Natural Science, Limnology Research Group, Egyetem u. 10, H-8200 Veszprém, Hungary, University of Pannonia, Egyetem u. 10, Veszprém, 8200 Hungary
| | - Judit Padisák
- ELKH-PE Limnoecology Research Group, Egyetem u. 10, Veszprém, 8200 Hungary
- University of Pannonia, Center of Natural Science, Limnology Research Group, Egyetem u. 10, H-8200 Veszprém, Hungary, University of Pannonia, Egyetem u. 10, Veszprém, 8200 Hungary
| | - Vanessa Becker
- Programa de Pós-Graduação em Ecologia, Departamento de Ecologia, Universidade Federal do Rio Grande do Norte, Av. Senador Salgado Filho 3000, Natal, RN Brazil
- Departamento de Engenharia Civil e Ambiental, Universidade Federal do Rio Grande do Norte, Av. Senador Salgado Filho 3000, Natal, RN Brasil
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6
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Yan H, Li Q, Chen B, Shi M, Zhang T. Identification and feeding characteristics of the mixotrophic flagellate Poterioochromonas malhamensis, a microalgal predator isolated from planting water of Pontederia cordata. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:40599-40611. [PMID: 35084678 DOI: 10.1007/s11356-022-18614-3] [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: 05/04/2021] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
The microorganisms and allelochemicals in Pontederia cordata planting water may have a synergistic inhibitory effect on algae. To study this synergy, an algae-inhibiting organism was isolated and identified, and its growth and feeding characteristics were studied. The organism was identified as Poterioochromonas malhamensis yzs924 based on both its morphology and molecular barcoding employing 18S rDNA gene sequences.The growth and feeding of P. malhamensis were affected by environmental factors and the state of its prey. (1) P. malhamensis is a mixotrophic flagellate. Its heterotrophic growth was the fastest in a wheat grain medium, and its growth rate in this study reached 2.5 day-1. (2) Within a short period of time (2 days), P. malhamensis growth was slower under continuous dark conditions than under alternating light and dark conditions, but it fed on Microcystis aeruginosa more rapidly under dark conditions. (3) High pH was disadvantageous to the growth and grazing of P. malhamensis. When the pH was kept stable at 9, P. malhamensis could not grow continuously. (4) When the initial density of M. aeruginosa was 5 × 107 cells/mL or is in a period of decline, P. malhamensis could not remove all M. aeruginosa. The combined use of P. malhamensis and allelochemicals may represent a method of M. aeruginosa control, but this approach requires further research.
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Affiliation(s)
- Hao Yan
- College of Life Sciences, Anhui Normal University, 241000, Wuhu, China
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, Anhui Normal University, Wuhu, 241000, China
| | - Qin Li
- College of Life Sciences, Anhui Normal University, 241000, Wuhu, China
| | - Bo Chen
- College of Life Sciences, Anhui Normal University, 241000, Wuhu, China
| | - Mei Shi
- College of Life Sciences, Anhui Normal University, 241000, Wuhu, China
| | - Tingting Zhang
- College of Life Sciences, Anhui Normal University, 241000, Wuhu, China.
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7
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Wei J, Li X, Xu X, Xu W, Chen Y, Zhang L, Yang Z, Huang Y. Elevated temperature mitigates the prolonged effect of high nitrogen on Microcystis aeruginosa removal through mixotrophic Ochromonas gloeopara grazing. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 820:153267. [PMID: 35074368 DOI: 10.1016/j.scitotenv.2022.153267] [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: 11/24/2021] [Revised: 01/14/2022] [Accepted: 01/15/2022] [Indexed: 06/14/2023]
Abstract
Cyanobacterial blooms are increasingly threatening the aquatic ecosystem functioning as a result of the global warming and eutrophication. The "top-down" control of cyanobacteria from consumers like the protozoans shows great potential because of the effectiveness and environment-friendliness. To reveal how the nutrition availability and elevated temperature affect the cyanobacteria removal through protozoans grazing, we grew the toxic Microcystis aeruginosa and the mixotrophic Ochromonas gloeopara in monocultures and cocultures at environmentally relevant nitrogen levels (0.5-8.0 mg L-1) under 25 °C and 30 °C, respectively. The growth of M. aeruginosa in monocultures was significantly enhanced as nitrogen concentration and temperature rose, partially benefitting from the promoted photosynthesis. By contrast, nitrogen availability affected neither the photoautotrophic growth nor the feeding on Microcystis of the mixotrophic O. gloeopara, but high temperature induced the mixotroph to be more heterotrophic as evidenced by the suppressed photosynthesis but strengthened feeding activity. Accordingly, the M. aeruginosa removal through O. gloeopara grazing in cocultures was delayed with increasing nitrogen, which, however, was sharply accelerated by elevated temperature. Based on the Gaussian models fitting, the theoretical time that the Microcystis was removed at 25 °C was prolonged from about 7.5 days to 10 days with increased nitrogen, but it was reduced to less than 4.6 days in all groups at 30 °C. While the intensity of Microcystis blooms is strongly positively correlated to the nutrition availability and temperature, the present study provided references for the practical application of Microcystis removal through grazing outdoors.
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Affiliation(s)
- Junjun Wei
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Biological Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China
| | - Xianxian Li
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Biological Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China
| | - Xiaoqing Xu
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Biological Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China
| | - Wenjie Xu
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Biological Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China
| | - Yitong Chen
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Biological Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China
| | - Lu Zhang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Biological Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China
| | - Zhou Yang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Biological Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China
| | - Yuan Huang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Biological Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China.
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8
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Nowruzi B, Shishir MA, Porzani SJ, Ferdous UT. Exploring the Interactions between Algae and Bacteria. Mini Rev Med Chem 2022; 22:2596-2607. [PMID: 35507745 DOI: 10.2174/1389557522666220504141047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/01/2022] [Accepted: 03/17/2022] [Indexed: 11/22/2022]
Abstract
Humans have used algae for hundreds of years to make various products viz. agar, fertilizer, food, and pigments. Algae are also used in bioremediation to clean up polluted water and as essential laboratory tools in genomics, proteomics, and other research applications such as environmental warnings. Several special features of algae, including the oxygenic photosynthesis, higher yield in biomass, growth on the non-arable lands, their survival in a wide range of water supplies (contaminated or filtered waters), the production of necessary byproducts and biofuels, the enhancement of soil productivity, and the greenhouse gas emissions, etc. altogether rendered them as vital bio-resources in the sustainable development. Algae and bacteria have been assumed to coexist from the early stages of the development of the earth, and a wide variety of interactions were observed between them which have influenced the ecosystems ranging from the oceans to the lichens. Research has shown that bacteria and algae interact synergistically, especially roseobacter-algae interactions being the most common. These interactions are common to all ecosystems and characterize their primary efficiency. The commercialization of algae for industrial purposes, an important field, is also influenced by this interaction which frequently results in bacterial infections among the consumers. However, the recent findings have revealed that the bacteria improve algal growth and support flocculation which are very crucial in algal biotechnology. Some of the most exciting advancements in the area of algal biotic interactions and potential difficulties were reviewed in this article. Information gleaned in this study would provide a firm foundation for launching more contemporaneous research efforts in understanding and utilizing the algal species in biotechnology industries and medical sectors.
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Affiliation(s)
- Bahareh Nowruzi
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | | | - Samaneh J Porzani
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Umme Tamanna Ferdous
- Aquatic Animal Health and Therapeutics Laboratory (AquaHealth), Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
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Vilar MCP, da Costa Pena Rodrigues TF, da Silva Ferrão-Filho A, de Oliveira E Azevedo SMF. Grazer-Induced Chemical Defense in a Microcystin-Producing Microcystis aeruginosa (Cyanobacteria) Exposed to Daphnia gessneri Infochemicals. J Chem Ecol 2021; 47:847-858. [PMID: 34569003 DOI: 10.1007/s10886-021-01315-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/09/2021] [Accepted: 09/14/2021] [Indexed: 10/20/2022]
Abstract
Cyanobacteria are photosynthetic microorganisms that compose phytoplankton and therefore have a trophic relationship with zooplankton, which represent an important link for energy flux in aquatic food webs. Several species can form blooms and produce bioactive metabolites known as cyanotoxins. However, the ecological and adaptative role of these toxins are still under debate. Many studies have addressed the cyanotoxins' function in defense against herbivory when grazing pressure by zooplankton plays a role in phytoplankton top-down control. Thus, the present study evaluated the ecophysiological responses of the cyanobacterial strain Microcystis aeruginosa NPLJ-4 underlying the chemical induced defense against the cladoceran Daphnia gessneri. Exposure to predator infochemicals consisted of cultures established in ASM-1 medium prepared in a filtrate from a culture of adults of D. gessneri at an environmentally relevant density. Daphnia infochemicals promoted a significant increase in toxin production by M. aeruginosa. However, no differences in growth were observed, despite a significant increase in both maximum photosynthetic efficiency and electron transport rate in response to zooplankton. Additionally, there was no significant variation in the production of exopolysaccharides. Overall, although a grazer-induced defense response was demonstrated, there were no effects on M. aeruginosa fitness, which maintained its growth in the presence of Daphnia alarm cues.
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Affiliation(s)
- Mauro Cesar Palmeira Vilar
- Laboratory of Ecophysiology and Toxicology of Cyanobacteria, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, 21949-902, Brazil.
| | - Thiago Ferreira da Costa Pena Rodrigues
- Laboratory of Ecophysiology and Toxicology of Cyanobacteria, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, 21949-902, Brazil
| | - Aloysio da Silva Ferrão-Filho
- Laboratory of Evaluation and Promotion of Environmental Health, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, RJ, 21040-360, Brazil
| | - Sandra Maria Feliciano de Oliveira E Azevedo
- Laboratory of Ecophysiology and Toxicology of Cyanobacteria, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, 21949-902, Brazil
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10
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Vilar MCP, Rodrigues TFCP, Silva LO, Pacheco ABF, Ferrão-Filho AS, Azevedo SMFO. Ecophysiological Aspects and sxt Genes Expression Underlying Induced Chemical Defense in STX-Producing Raphidiopsis raciborskii (Cyanobacteria) against the Zooplankter Daphnia gessneri. Toxins (Basel) 2021; 13:406. [PMID: 34200983 PMCID: PMC8230027 DOI: 10.3390/toxins13060406] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/31/2021] [Accepted: 06/02/2021] [Indexed: 11/16/2022] Open
Abstract
Cyanobacteria stand out among phytoplankton when they form massive blooms and produce toxins. Because cyanotoxin genes date to the origin of metazoans, the hypothesis that cyanotoxins function as a defense against herbivory is still debated. Although their primary cellular function might vary, these metabolites could have evolved as an anti-predator response. Here we evaluated the physiological and molecular responses of a saxitoxin-producing Raphidiopsis raciborskii to infochemicals released by the grazer Daphnia gessneri. Induced chemical defenses were evidenced in R. raciborskii as a significant increase in the transcription level of sxt genes, followed by an increase in saxitoxin content when exposed to predator cues. Moreover, cyanobacterial growth decreased, and no significant effects on photosynthesis or morphology were observed. Overall, the induced defense response was accompanied by a trade-off between toxin production and growth. These results shed light on the mechanisms underlying zooplankton-cyanobacteria interactions in aquatic food webs. The widespread occurrence of the cyanobacterium R. raciborskii in freshwater bodies has been attributed to its phenotypic plasticity. Assessing the potential of this species to thrive over interaction filters such as zooplankton grazing pressure can enhance our understanding of its adaptive success.
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Affiliation(s)
- Mauro C. P. Vilar
- Laboratory Ecophysiology and Toxicology of Cyanobacteria, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro 21949-902, Brazil; (T.F.C.P.R.); (L.O.S.); (S.M.F.O.A.)
| | - Thiago F. C. P. Rodrigues
- Laboratory Ecophysiology and Toxicology of Cyanobacteria, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro 21949-902, Brazil; (T.F.C.P.R.); (L.O.S.); (S.M.F.O.A.)
| | - Luan O. Silva
- Laboratory Ecophysiology and Toxicology of Cyanobacteria, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro 21949-902, Brazil; (T.F.C.P.R.); (L.O.S.); (S.M.F.O.A.)
| | - Ana Beatriz F. Pacheco
- Laboratory Biological Physics, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro 21949-902, Brazil;
| | - Aloysio S. Ferrão-Filho
- Laboratory of Evaluation and Promotion of Environmental Health, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro 21040-360, Brazil;
| | - Sandra M. F. O. Azevedo
- Laboratory Ecophysiology and Toxicology of Cyanobacteria, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro 21949-902, Brazil; (T.F.C.P.R.); (L.O.S.); (S.M.F.O.A.)
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Mirasbekov Y, Zhumakhanova A, Zhantuyakova A, Sarkytbayev K, Malashenkov DV, Baishulakova A, Dashkova V, Davidson TA, Vorobjev IA, Jeppesen E, Barteneva NS. Semi-automated classification of colonial Microcystis by FlowCAM imaging flow cytometry in mesocosm experiment reveals high heterogeneity during seasonal bloom. Sci Rep 2021; 11:9377. [PMID: 33931681 PMCID: PMC8087837 DOI: 10.1038/s41598-021-88661-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 04/05/2021] [Indexed: 02/02/2023] Open
Abstract
A machine learning approach was employed to detect and quantify Microcystis colonial morphospecies using FlowCAM-based imaging flow cytometry. The system was trained and tested using samples from a long-term mesocosm experiment (LMWE, Central Jutland, Denmark). The statistical validation of the classification approaches was performed using Hellinger distances, Bray-Curtis dissimilarity, and Kullback-Leibler divergence. The semi-automatic classification based on well-balanced training sets from Microcystis seasonal bloom provided a high level of intergeneric accuracy (96-100%) but relatively low intrageneric accuracy (67-78%). Our results provide a proof-of-concept of how machine learning approaches can be applied to analyze the colonial microalgae. This approach allowed to evaluate Microcystis seasonal bloom in individual mesocosms with high level of temporal and spatial resolution. The observation that some Microcystis morphotypes completely disappeared and re-appeared along the mesocosm experiment timeline supports the hypothesis of the main transition pathways of colonial Microcystis morphoforms. We demonstrated that significant changes in the training sets with colonial images required for accurate classification of Microcystis spp. from time points differed by only two weeks due to Microcystis high phenotypic heterogeneity during the bloom. We conclude that automatic methods not only allow a performance level of human taxonomist, and thus be a valuable time-saving tool in the routine-like identification of colonial phytoplankton taxa, but also can be applied to increase temporal and spatial resolution of the study.
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Affiliation(s)
- Yersultan Mirasbekov
- grid.428191.70000 0004 0495 7803School of Sciences and Humanities, Nazarbayev University, Nur-Sultan, 010000 Kazakhstan
| | - Adina Zhumakhanova
- grid.428191.70000 0004 0495 7803School of Sciences and Humanities, Nazarbayev University, Nur-Sultan, 010000 Kazakhstan
| | - Almira Zhantuyakova
- grid.428191.70000 0004 0495 7803School of Sciences and Humanities, Nazarbayev University, Nur-Sultan, 010000 Kazakhstan ,grid.17091.3e0000 0001 2288 9830Present Address: University of British Columbia, Vancouver, Canada
| | - Kuanysh Sarkytbayev
- grid.428191.70000 0004 0495 7803School of Sciences and Humanities, Nazarbayev University, Nur-Sultan, 010000 Kazakhstan ,National Laboratory Astana, Nur-Sultan, 010000 Kazakhstan
| | - Dmitry V. Malashenkov
- grid.14476.300000 0001 2342 9668Department of General Ecology and Hydrobiology, Lomonosov Moscow State University, 119991 Moscow, Russian Federation
| | - Assel Baishulakova
- grid.428191.70000 0004 0495 7803School of Sciences and Humanities, Nazarbayev University, Nur-Sultan, 010000 Kazakhstan
| | - Veronika Dashkova
- grid.428191.70000 0004 0495 7803School of Sciences and Humanities, Nazarbayev University, Nur-Sultan, 010000 Kazakhstan ,grid.428191.70000 0004 0495 7803School of Engineering and Digital Sciences, Nazarbayev University, Nur-Sultan, 010000 Kazakhstan
| | - Thomas A. Davidson
- grid.7048.b0000 0001 1956 2722Department of Bioscience, Aarhus University, 8600 Silkeborg, Denmark
| | - Ivan A. Vorobjev
- grid.428191.70000 0004 0495 7803School of Sciences and Humanities, Nazarbayev University, Nur-Sultan, 010000 Kazakhstan ,National Laboratory Astana, Nur-Sultan, 010000 Kazakhstan
| | - Erik Jeppesen
- grid.7048.b0000 0001 1956 2722Department of Bioscience, Aarhus University, 8600 Silkeborg, Denmark ,grid.6935.90000 0001 1881 7391Institute of Marine Sciences, Middle East Technical University, Mersin, 33731 Turkey ,grid.6935.90000 0001 1881 7391Limnology Laboratory, Department of Biological Sciences and Centre for Ecosystem Research and Implementation, Middle East Technical University, Ankara, 06800 Turkey ,grid.484648.20000 0004 0480 4559Sino-Danish Centre for Education and Research, Beijing, 100049 China
| | - Natasha S. Barteneva
- grid.428191.70000 0004 0495 7803School of Sciences and Humanities, Nazarbayev University, Nur-Sultan, 010000 Kazakhstan ,grid.428191.70000 0004 0495 7803The Environmental Research and Efficiency Cluster (EREC), Nazarbayev University, Nur-Sultan, 010000 Kazakhstan
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Oxidative Stress and Antioxidant Responses of Phormidium ambiguum and Microcystis aeruginosa Under Diurnally Varying Light Conditions. Microorganisms 2020; 8:microorganisms8060890. [PMID: 32545576 PMCID: PMC7357134 DOI: 10.3390/microorganisms8060890] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/05/2020] [Accepted: 06/10/2020] [Indexed: 12/22/2022] Open
Abstract
Two harmful cyanobacteria species (Phormidium ambiguum and Microcystis aeruginosa) were exposed to diurnal light-intensity variation to investigate their favorable and stressed phases during a single day. The photosynthetically active radiation (PAR) started at 0 µmol·m−2·s−1 (06:00 h), increased by ~25 µmol·m−2·s−1 or ~50 µmol·m−2·s−1 every 30 min, peaking at 300 µmol·m−2·s−1 or 600 µmol·m−2·s−1 (12:00 h), and then decreased to 0 µmol·m−2·s−1 (by 18:00 h). The H2O2 and antioxidant activities were paralleled to light intensity. Higher H2O2 and antioxidant levels (guaiacol peroxidase, catalase (CAT), and superoxidase dismutase) were observed at 600 µmol·m−2·s−1 rather than at 300 µmol·m−2·s−1. Changes in antioxidant levels under each light condition differed between the species. Significant correlations were observed between antioxidant activities and H2O2 contents for both species, except for the CAT activity of P. ambiguum at 300 µmol·m−2·s−1. Under each of the conditions, both species responded proportionately to oxidative stress. Even under maximum light intensities (300 µmol·m−2·s−1 or 600 µmol·m−2·s−1 PAR intensity), neither species was stressed. Studies using extended exposure durations are warranted to better understand the growth performance and long-term physiological responses of both species.
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Effects of Light Intensity and Exposure Period on the Growth and Stress Responses of Two Cyanobacteria Species: Pseudanabaena galeata and Microcystis aeruginosa. WATER 2020. [DOI: 10.3390/w12020407] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Light is an important factor that affects cyanobacterial growth and changes in light can influence their growth and physiology. However, an information gap exists regarding light-induced oxidative stress and the species-specific behavior of cyanobacteria under various light levels. This study was conducted to evaluate the comparative effects of different light intensities on the growth and stress responses of two cyanobacteria species, Pseudanabaena galeata (strain NIES 512) and Microcystis aeruginosa (strain NIES 111), after periods of two and eight days. The cyanobacterial cultures were grown under the following different light intensities: 0, 10, 30, 50, 100, 300, and 600 μmol m−2 s−1. The optical density (OD730), chlorophyll a (Chl-a) content, protein content, H2O2 content, and the antioxidative enzyme activities of catalase (CAT) and peroxidase (POD) were measured separately in each cyanobacteria species. P. galeata was negatively affected by light intensities lower than 30 μmol m−2 s−1 and higher than 50 μmol m−2 s−1. A range of 30 to 50 μmol m−2 s−1 light was favorable for the growth of P. galeata, whereas M. aeruginosa had a higher tolerance for extreme light conditions. The favorable range for M. aeruginosa was 10 to 100 μmol m−2 s−1.
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