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Cameron ES, Krishna A, Emelko MB, Müller KM. Sporadic diurnal fluctuations of cyanobacterial populations in oligotrophic temperate systems can prevent accurate characterization of change and risk in aquatic systems. WATER RESEARCH 2024; 252:121199. [PMID: 38330712 DOI: 10.1016/j.watres.2024.121199] [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: 07/12/2023] [Revised: 01/12/2024] [Accepted: 01/23/2024] [Indexed: 02/10/2024]
Abstract
Cyanobacteria increasingly threaten recreational water use and drinking water resources globally. They require dynamic monitoring to account for variability in their distribution arising from diel cycles associated with oscillatory vertical migration. While this has been discussed in marine and eutrophic freshwater contexts, reports of diurnal vertical migration of cyanobacteria in oligotrophic freshwater lakes are scant. Typical monitoring protocols do not reflect these dynamics and frequently focus only on surface water sampling approaches, and either ignore sampling time or recommend large midday timeframes (e.g., 10AM-3PM), thereby preventing accurate characterization of cyanobacterial community dynamics. To evaluate the impact of diurnal migrations and water column stratification on cyanobacterial abundance and composition, communities were characterized in a shallow well-mixed lake interconnected to a thermally stratified lake in the Turkey Lakes Watershed (Ontario, Canada) using amplicon sequencing of the 16S rRNA gene across a multi-time point sampling series in 2018 and 2022. This work showed that cyanobacteria are present in oligotrophic lakes and their community structure varies (i) diurnally, (ii) across the depth of the water column, (iii) interannually within the same lake and (iv) between different lakes that are closely interconnected within the same watershed. It underscored the need for integrating multi-timepoint, multi-depth discrete sampling guidance into lake and reservoir monitoring programs to describe cyanobacteria community dynamics and signal change to inform risk management associated with the potential for cyanotoxin production. Ignoring variability in cyanobacterial community dynamics (such as that reported herein) and reducing sample numbers can lead to a false sense of security and missed opportunities to identify and mitigate changes in trophic status and associated risks such as toxin or taste and odor production, especially in sensitive, oligotrophic systems.
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Affiliation(s)
- Ellen S Cameron
- Department of Biology, University of Waterloo, 200 University Ave. W, Waterloo, Ontario, N2L 3G1, Canada
| | - Anjali Krishna
- Department of Biology, University of Waterloo, 200 University Ave. W, Waterloo, Ontario, N2L 3G1, Canada
| | - Monica B Emelko
- Department of Civil & Environmental Engineering, University of Waterloo, 200 University Ave. W, Waterloo, Ontario, N2L 3G1, Canada
| | - Kirsten M Müller
- Department of Biology, University of Waterloo, 200 University Ave. W, Waterloo, Ontario, N2L 3G1, Canada.
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Mermans F, Mattelin V, Van den Eeckhoudt R, García-Timermans C, Van Landuyt J, Guo Y, Taurino I, Tavernier F, Kraft M, Khan H, Boon N. Opportunities in optical and electrical single-cell technologies to study microbial ecosystems. Front Microbiol 2023; 14:1233705. [PMID: 37692384 PMCID: PMC10486927 DOI: 10.3389/fmicb.2023.1233705] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 08/03/2023] [Indexed: 09/12/2023] Open
Abstract
New techniques are revolutionizing single-cell research, allowing us to study microbes at unprecedented scales and in unparalleled depth. This review highlights the state-of-the-art technologies in single-cell analysis in microbial ecology applications, with particular attention to both optical tools, i.e., specialized use of flow cytometry and Raman spectroscopy and emerging electrical techniques. The objectives of this review include showcasing the diversity of single-cell optical approaches for studying microbiological phenomena, highlighting successful applications in understanding microbial systems, discussing emerging techniques, and encouraging the combination of established and novel approaches to address research questions. The review aims to answer key questions such as how single-cell approaches have advanced our understanding of individual and interacting cells, how they have been used to study uncultured microbes, which new analysis tools will become widespread, and how they contribute to our knowledge of ecological interactions.
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Affiliation(s)
- Fabian Mermans
- Center for Microbial Ecology and Technology (CMET), Department of Biotechnology, Ghent University, Ghent, Belgium
- Department of Oral Health Sciences, KU Leuven, Leuven, Belgium
| | - Valérie Mattelin
- Center for Microbial Ecology and Technology (CMET), Department of Biotechnology, Ghent University, Ghent, Belgium
| | - Ruben Van den Eeckhoudt
- Micro- and Nanosystems (MNS), Department of Electrical Engineering (ESAT), KU Leuven, Leuven, Belgium
| | - Cristina García-Timermans
- Center for Microbial Ecology and Technology (CMET), Department of Biotechnology, Ghent University, Ghent, Belgium
| | - Josefien Van Landuyt
- Center for Microbial Ecology and Technology (CMET), Department of Biotechnology, Ghent University, Ghent, Belgium
| | - Yuting Guo
- Center for Microbial Ecology and Technology (CMET), Department of Biotechnology, Ghent University, Ghent, Belgium
| | - Irene Taurino
- Micro- and Nanosystems (MNS), Department of Electrical Engineering (ESAT), KU Leuven, Leuven, Belgium
- Semiconductor Physics, Department of Physics and Astronomy, KU Leuven, Leuven, Belgium
| | - Filip Tavernier
- MICAS, Department of Electrical Engineering (ESAT), KU Leuven, Leuven, Belgium
| | - Michael Kraft
- Micro- and Nanosystems (MNS), Department of Electrical Engineering (ESAT), KU Leuven, Leuven, Belgium
- Leuven Institute of Micro- and Nanoscale Integration (LIMNI), KU Leuven, Leuven, Belgium
| | - Hira Khan
- Center for Microbial Ecology and Technology (CMET), Department of Biotechnology, Ghent University, Ghent, Belgium
| | - Nico Boon
- Center for Microbial Ecology and Technology (CMET), Department of Biotechnology, Ghent University, Ghent, Belgium
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Mutoti MI, Jideani AIO, Gumbo JR. Using FlowCam and molecular techniques to assess the diversity of Cyanobacteria species in water used for food production. Sci Rep 2022; 12:18995. [PMID: 36348060 PMCID: PMC9643327 DOI: 10.1038/s41598-022-23818-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 11/07/2022] [Indexed: 11/09/2022] Open
Abstract
Globally, the occurrence of cyanobacteria in water currently remains an important subject as they produce cyanotoxins that pose threat to human health. Studies on the contamination of maize meals during mill grinding processes using cyanobacteria-contaminated water have not been conducted. The present study aimed to assess the diversity of cyanobacteria in the samples (process water, uncooked maize meal, and cooked maize meal (porridge)). Polymerized Chain Reaction (PCR) and Advanced digital flow cytometry (FlowCAM) were used to detect and identify cyanobacterial species available in these samples. 16S Primers (forward and reverse) tailed with Universal Sequences were used for amplification and sequencing of full-length 16S rRNA genes from cyanobacteria found in all samples. Cyanobacterial species from order Nostocales, Pseudanabaenales, Oscillatoriales Chroococcales, Synechococcales, and unclassified cyanobacterial order, some of which have the potential to produce cyanotoxins were amplified and identified in process water, raw maize meal and porridge samples using PCR. Images of the genus Microcystis, Phormidium, and Leptolyngbya were captured in process water samples using FlowCAM. These findings show the presence of cyanobacteria species in process water used for maize meal and the absence in cooked maize meal. The presence of cyanobacteria in process water is likely another route of human exposure to cyanotoxins.
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Affiliation(s)
- Mulalo I. Mutoti
- grid.412964.c0000 0004 0610 3705Department of Earth Sciences, Faculty of Science, Engineering and Agriculture, University of Venda, Private Bag, Thohoyandou, X50500950 South Africa
| | - Afam I. O. Jideani
- grid.412964.c0000 0004 0610 3705Department of Food Science and Technology, Faculty of Science, Engineering and Agriculture, University of Venda, Private Bag X5050, Thohoyandou, 0950 South Africa ,Special Interest Group Post Harvest Handling, ISEKI-Food Association, Muthgasse 18, 1190 Vienna, Austria
| | - Jabulani R. Gumbo
- grid.412964.c0000 0004 0610 3705Department of Earth Sciences, Faculty of Science, Engineering and Agriculture, University of Venda, Private Bag, Thohoyandou, X50500950 South Africa
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Giannuzzi L, Lombardo T, Juárez I, Aguilera A, Blanco G. A Stochastic Characterization of Hydrogen Peroxide-Induced Regulated Cell Death in Microcystis aeruginosa. Front Microbiol 2021; 12:636157. [PMID: 34394016 PMCID: PMC8356053 DOI: 10.3389/fmicb.2021.636157] [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: 12/01/2020] [Accepted: 05/25/2021] [Indexed: 01/26/2023] Open
Abstract
Regulated cell death (RCD) encompasses the activation of cellular pathways that initiate and execute a self-dismissal process. RCD occur over a range of stressors doses that overcome pro-survival cellular pathways, while higher doses cause excessive damage leading to passive accidental cell death (ACD). Hydrogen peroxide (HP) has been proposed as a potential tool to control harmful cyanobacterial blooms, given its capacity to remove cyanobacterial cells and oxidize cyanotoxins. HP is a source of hydroxyl radicals and is expected to induce RCD only within a limited range of concentrations. This property makes this compound very useful to better understand stress-driven RCD. In this work, we analyzed cell death in microcystin-producing Microcystis aeruginosa by means of a stochastic dose response model using a wide range of HP concentrations (0, 0.29, 1.76, 3.67, 7.35, 14.70, and 29.5 mM). We used flow cytometry and unsupervised classification to study cell viability and characterize transitional cell death phenotypes after exposing cells to HP for 48 and 72 h. Non-linear regression was used to fit experimental data to a logistic cumulative distribution function (cdf) and calculate the half maximal effective concentration (EC50). The EC50 of M. aeruginosa exposed to HP were 3.77 ± 0.26 mM and 4.26 ± 0.22 mM at 48 and 72 h, respectively. The derivative of cdf (probability density function; pdf) provided theoretical and practical demonstration that EC50 is the minimal dose required to cause RCD in 50% of cells, therefore maximizing the probability of RCD occurrence. 1.76 mM HP lead to an antioxidant stress response characterized by increased reactive oxygen species (ROS) levels and HP decomposition activity. The exposure of 3.67 mM HP induced a dose-related transition in cell death phenotype, and produced several morphological changes (a less dense stroma, distortion of the cell membrane, partial disintegration of thylakoids, extensive cytoplasmic vacuolation and highly condensed chromatin). The EC50 and the stochastic cdf and pdf together with the multidimensional transitional phenotypic analysis of single cells contribute to further characterize cell death pathways in cyanobacteria.
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Affiliation(s)
- Leda Giannuzzi
- Centro de Investigación y Desarrollo en Criotecnología de Alimentos, Consejo Nacional de Investigaciones Científicas y Tecnicas, Universidad Nacional de La Plata, La Plata, Argentina.,Área de Toxicología General, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Tomás Lombardo
- Laboratory of Immunotoxicology (LaITo), Facultad de Farmacia y Bioquímica, Instituto de Estudios de la Inmunidad Humoral Dr. Ricardo A. Margni (IDEHU) UBA-CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Iván Juárez
- Centro de Investigación y Desarrollo en Criotecnología de Alimentos, Consejo Nacional de Investigaciones Científicas y Tecnicas, Universidad Nacional de La Plata, La Plata, Argentina.,Área de Toxicología General, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Anabella Aguilera
- Centre for Ecology and Evolution in Microbial Model Systems (EEMiS), Linnaeus University, Kalmar, Sweden
| | - Guillermo Blanco
- Laboratory of Immunotoxicology (LaITo), Facultad de Farmacia y Bioquímica, Instituto de Estudios de la Inmunidad Humoral Dr. Ricardo A. Margni (IDEHU) UBA-CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina
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Mondal S, Kumar V, Singh SP. Oxidative stress measurement in different morphological forms of wild-type and mutant cyanobacterial strains: Overcoming the limitation of fluorescence microscope-based method. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 200:110730. [PMID: 32464439 DOI: 10.1016/j.ecoenv.2020.110730] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 04/22/2020] [Accepted: 05/07/2020] [Indexed: 06/11/2023]
Abstract
Monitoring of oxidative stress caused by a wide range of reactive oxygen species (ROS) is essential to have an idea about the fitness and growth of photosynthetic organisms. The imaging-based oxidative stress measurement in cyanobacteria using 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) dye has the limitation of small sample size as the only selected number of cells are analyzed to measure the ROS levels. Here, we developed a method for oxidative stress measurement by DCFH-DA and flow cytometer (FCM) using unicellular Synechococcus elongatus PCC 7942 and filamentous Fremyella diplosiphon BK14 cyanobacteria. F. diplosiphon BK14 inherently possess high levels of ROS and showed higher sensitivity to hydrogen peroxide treatment in comparison to S. elongatus PCC 7942. We successfully measured oxidative stress in glutaredoxin lacking strain (Δgrx3) of S. elongatus PCC 7942, and wild-type Synechocystis sp. PCC 6803 using FCM based method. Importantly, ROS were not detected in these two strains of cyanobacteria by fluorescence microscope-based method due to their small spherical morphology. Δgrx3 strain showed high ROS levels in comparison to its wild-type strain. Treatment of abiotic factors such as high PAR in wild-type and Δgrx3 strains of S. elongatus PCC 7942, low PAR or low PAR + UVR in wild-type S. elongatus PCC 7942, and high PAR or high PAR + NaCl in Synechocystis sp. PCC 6803 increased oxidative stress. In summary, the FCM based method can measure ROS levels produced due to physiological conditions associated with genetic changes or abiotic stress in a large population of cells regardless of their morphology. Therefore, the present study shows the usefulness of the method in monitoring the health of organisms in a large scale cultivation system.
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Affiliation(s)
- Soumila Mondal
- Centre of Advanced Study in Botany, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Vinod Kumar
- Centre of Advanced Study in Botany, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Shailendra P Singh
- Centre of Advanced Study in Botany, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
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