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Chmykh Y, Nadeau JL. The use of fluorescence lifetime imaging (FLIM) for in situ microbial detection in complex mineral substrates. J Microsc 2024; 294:36-51. [PMID: 38230460 DOI: 10.1111/jmi.13264] [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: 08/01/2023] [Revised: 12/16/2023] [Accepted: 01/09/2024] [Indexed: 01/18/2024]
Abstract
The utility of fluorescence lifetime imaging microscopy (FLIM) for identifying bacteria in complex mineral matrices was investigated. Baseline signals from unlabelled Bacillus subtilis and Euglena gracilis, and Bacillus subtilis labelled with SYTO 9 were obtained using two-photon excitation at 730, 750 and 800 nm, identifying characteristic lifetimes of photosynthetic pigments, unpigmented cellular autofluorescence, and SYTO 9. Labelled and unlabelled B. subtilis were seeded onto marble and gypsum samples containing endolithic photosynthetic cyanobacteria and the ability to distinguish cells from mineral autofluorescence and nonspecific dye staining was examined in parallel with ordinary multichannel confocal imaging. It was found that FLIM enabled discrimination of SYTO 9 labelled cells from background, but that the lifetime of SYTO 9 was shorter in cells on minerals than in pure culture under our conditions. Photosynthetic microorganisms were easily observed using both FLIM and confocal. Unlabelled, nonpigmented bacteria showed weak signals that were difficult to distinguish from background when minerals were present, though cellular autofluorescence consistent with NAD(P)H could be seen in pure cultures, and phasor analysis permitted detection on rocks. Gypsum and marble samples showed similar autofluorescence profiles, with little autofluorescence in the yellow-to-red range. Lifetime or time-gated imaging may prove a useful tool for environmental microbiology. LAY DESCRIPTION: The standard method of bacterial enumeration is to label the cells with a fluorescent dye and count them under high-power fluorescence microscopy. However, this can be difficult when the cells are embedded in soil and rock due to fluorescence from the surrounding minerals and dye binding to ambiguous features of the substrate. The use of fluorescence lifetime imaging (FLIM) can disambiguate these signals and allow for improved detection of bacteria in environmental samples.
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Affiliation(s)
- Yekaterina Chmykh
- Department of Physics, Portland State University, Portland, Oregon, USA
| | - Jay L Nadeau
- Department of Physics, Portland State University, Portland, Oregon, USA
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Wen D, Yu Y, Anderin Chuang CY, Jiang Y, Song H. Advancing sustainable seawater disinfection: Enhanced inactivation and mechanism of pulsed UV-LEDs irradiation on Tetraselmis sp. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 345:123425. [PMID: 38266700 DOI: 10.1016/j.envpol.2024.123425] [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: 08/25/2023] [Revised: 11/17/2023] [Accepted: 01/21/2024] [Indexed: 01/26/2024]
Abstract
Ultraviolet light-emitting diodes (UV-LEDs), as a novel ultraviolet light source with flexible pulse mode, has gained significant attention for applications in water disinfection and food sterilization. This study investigated the comparative inactivation efficiency of Tetraselmis sp. with continuous and pulsed UV-LEDs irradiation, exploring different wavelengths, duty rates and pulse frequencies. The results reveal a significant enhancement in inactivation efficiency (p < 0.05) under pulsed conditions even at the same UV dose, with inactivation efficiency increasing as duty rate or pulse frequency decreases. The optimal conditions for achieving peak inactivation efficacy are identified as a duty rate of 50% and a pulse frequency of 5 Hz. Within this parameter space, pulsed irradiation leads to a remarkable 1.7-fold increase in inactivation efficiency at UV265 nm and a 1.5-fold increase at UV285 nm compared to continuous irradiation, respectively. Additionally, the disruptive impacts on photosynthetic performance are more pronounced with pulsed irradiation, particularly at the 5 Hz pulse frequency. In shed of these findings, the application of pulsed UV-LEDs irradiation emerges as a promising alternative to the conventional continuous UV disinfection methods in the area of seawater disinfection, offering higher disinfection efficacy and energy consumption.
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Affiliation(s)
- Diya Wen
- State Key Laboratory of NBC Protection for Civilia, Beijing, China; International Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China
| | - Yifeng Yu
- International Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China
| | | | - Yuelu Jiang
- International Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China.
| | - Hua Song
- State Key Laboratory of NBC Protection for Civilia, Beijing, China
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Si B, Jing M, Jiang N, He Z, Han H, Chen M. Predictive analysis of effects of water stress on strawberry seedlings using fluorescent image channel components. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:125108. [PMID: 38117192 DOI: 10.1063/5.0166641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 11/29/2023] [Indexed: 12/21/2023]
Abstract
To investigate the effect of water stress on strawberry seedlings, a chlorophyll-fluorescence-image-acquisition system was developed. Strawberry seedlings of uniform growth were selected for grouped water-stress incubation experiments; the collected chlorophyll-fluorescence images of leaves were converted to red-green-blue (RGB), hue-saturation-value (HSV), and hue-saturation-intensity (HSI) color spaces and analyzed for water and chlorophyll contents measured at the same time for 14 consecutive days. The results indicate that the analysis and prediction of plant stress conditions can be effectively conducted using the channel components of the color-space model and the channel component ratios, which provide a reference for promoting agricultural development.
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Affiliation(s)
- Bingqi Si
- School of Mechanical Engineering, Shaanxi University of Technology, Hanzhong, Shaanxi 723000, China
| | - Min Jing
- School of Mechanical Engineering, Shaanxi University of Technology, Hanzhong, Shaanxi 723000, China
- Key Laboratory of Industrial Automation in Shaanxi Province, Hanzhong 723000, China
| | - Ningchao Jiang
- School of Mechanical Engineering, Shaanxi University of Technology, Hanzhong, Shaanxi 723000, China
| | - Zhaonan He
- School of Mechanical Engineering, Shaanxi University of Technology, Hanzhong, Shaanxi 723000, China
| | - Hengtong Han
- School of Mechanical Engineering, Shaanxi University of Technology, Hanzhong, Shaanxi 723000, China
| | - Manlong Chen
- School of Mechanical Engineering, Shaanxi University of Technology, Hanzhong, Shaanxi 723000, China
- Key Laboratory of Industrial Automation in Shaanxi Province, Hanzhong 723000, China
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Gutiérrez CL, Muñoz C, San Martín M, Cadoret JP, Henríquez V. Chloroplast Dual Divergent Promoter Plasmid for Heterologous Protein Expression in Tetraselmis suecica (Chlorophyceae, Chlorodendrales). JOURNAL OF PHYCOLOGY 2020; 56:1066-1076. [PMID: 32359200 DOI: 10.1111/jpy.13013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 02/24/2020] [Accepted: 04/14/2020] [Indexed: 06/11/2023]
Abstract
The eukaryotic green microalga Tetraselmis suecica is commonly used for aquaculture purposes because of its high stress tolerance and ease of culture in a wide spectrum of environments; they are therefore suitable candidates for biotechnology applications. To date, no data are available regarding chloroplast transformation vectors based on specific endogenous promoters and homologous targeting regions. We report on the identification of Tetraselmis suecica genes encoding the ribulose bisphosphate carboxylase/oxygenase large subunit protein, the photosystem II D1 protein and the ATP synthase CF1-beta subunit protein together with their untranslated regions (5'UTR, 3'UTR). The full-length ORFs of the putative genes with their regulatory sequences were obtained. We were also able to identify the downstream 3' end of the large subunit ribosomal RNA gene (23S) along with the 5S RNA end-to-end with the psbA gene on the complementary strand. The intergenic region between these genes appears to be a good target site for the integration of target proteins. Moreover, we identified a back-to-back promoter region among the rbcL and atpB genes. To assess the bidirectionality activities of both promoters, a dual reporter vector was constructed for Tetraselmis suecica transformation containing the cat and TurboGFP genes driven by the 5'rbcL/5'atpB divergent promoter. The vector included the 23S-5S and psbA nucleotide sequences as flanking regions. These flanking regions provided suitable insertion sites within the chloroplast genome for cassette integration via homologous recombination. Simultaneous expression of the chloramphenicol-resistant conferring gene and the gene coding for TurboGFP driven by 5'rbcL/5'atpB showed a potent natural bidirectional promoter as a reliable genetic tool.
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Affiliation(s)
- Carla L Gutiérrez
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Carla Muñoz
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Margarita San Martín
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | | | - Vitalia Henríquez
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
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Marcek Chorvatova A, Uherek M, Mateasik A, Chorvat D. Time-resolved endogenous chlorophyll fluorescence sensitivity to pH: study on Chlorella sp. algae. Methods Appl Fluoresc 2020; 8:024007. [PMID: 32074513 DOI: 10.1088/2050-6120/ab77f4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
To better understand pH-dependence of endogenous fluorescence of algae, we employed spectroscopy and microscopy methods, including advanced time-resolved fluorescence imaging microscopy (FLIM), using green algae Chlorella sp. as a model system. Absorption spectra confirmed two peaks, at 400-420 nm and 670 nm. Emission was maximal at 680 nm, with smaller peaks between 520 and 540 nm. Acidification led to a gradual decrease in the red fluorescence intensity with the maximum at 680 nm when excited by 450 nm laser. FLIM measurements, performed using 475 nm picoseconds excitation, uncovered that this effect is accompanied by a shortening of the tau1 fluorescence lifetime. Under severe acidification, we also noted an increase in the green fluorescence with a maximum between 520-540 nm and a shift toward 690-700 nm of the red fluorescence, accompanied by prolongation of the tau2 fluorescence lifetime. Gathered data increase our knowledge on the responsiveness of algae to acidification and indicate that endogenous fluorescence derived from chlorophylls can potentially serve as a biosensing tool for monitoring pH change in its natural environment.
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Affiliation(s)
- A Marcek Chorvatova
- Department of Biophotonics, International Laser Centre, Ilkovicova 3, 84104 Bratislava, Slovakia. Department of Biophysics, Faculty of Natural Sciences, University of Ss. Cyril and Methodius, nam. J Herdu 2, 91701 Trnava, Slovakia
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Pavlinska Z, Chorvat D, Mateasik A, Jerigova M, Velic D, Ivošević DeNardis N, Marcek Chorvatova A. Fluorescence responsiveness of unicellular marine algae Dunaliella to stressors under laboratory conditions. J Biotechnol 2020; 324S:100018. [PMID: 34154733 DOI: 10.1016/j.btecx.2020.100018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 03/06/2020] [Accepted: 05/04/2020] [Indexed: 11/25/2022]
Abstract
We examined the responsiveness of unicellular green alga Dunalliela tertiolecta to selected stressors employing confocal- and time-resolved imaging of endogenous fluorescence. Our aim was to monitor cell endogenous fluorescence changes under exposure to heavy metal Cd, acidification, as well as light by laser-induced photobleaching. The accumulation of Cd in algae cells was confirmed by the secondary ion mass spectroscopy technique. For the first time, custom-made computational techniques were employed to evaluate separately the fluorescence in the flagella vs. the body region. In the presence of Cd, we recorded increase in the green fluorescence in the flagella region in the form of opacities, without change in the fluorescence lifetimes, suggesting higher availability of the fluorescent molecules. Under acidification, we noted significant rise in the green fluorescence in the flagella region, but associated with longer fluorescence lifetimes, pointing to changes in the algae environment. Photobleaching experiments corroborated gathered observations. Obtained data support a differential responsiveness of the flagella vs. the body region to stressors and enable us to better understand the pathophysiological changes of algal cells in culture under stress conditions.
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Affiliation(s)
- Zuzana Pavlinska
- International Laser Centre, Ilkovicova 3, 84104 Bratislava, Slovakia; Faculty of Natural Sciences, University of Ss. Cyril and Methodius, nam. J Herdu 1, 91702 Trnava, Slovakia
| | - Dusan Chorvat
- International Laser Centre, Ilkovicova 3, 84104 Bratislava, Slovakia
| | - Anton Mateasik
- International Laser Centre, Ilkovicova 3, 84104 Bratislava, Slovakia
| | - Monika Jerigova
- International Laser Centre, Ilkovicova 3, 84104 Bratislava, Slovakia; Comenius University, Faculty of Natural Sciences, Department of Physical and Theoretical Chemistry, Ilkovicova 6, Bratislava 4, 84215, Slovakia
| | - Dusan Velic
- International Laser Centre, Ilkovicova 3, 84104 Bratislava, Slovakia; Comenius University, Faculty of Natural Sciences, Department of Physical and Theoretical Chemistry, Ilkovicova 6, Bratislava 4, 84215, Slovakia
| | | | - Alzbeta Marcek Chorvatova
- International Laser Centre, Ilkovicova 3, 84104 Bratislava, Slovakia; Faculty of Natural Sciences, University of Ss. Cyril and Methodius, nam. J Herdu 1, 91702 Trnava, Slovakia.
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Kim YS, Kim JJ, Park SI, Diamond S, Boyd JS, Taton A, Kim IS, Golden JW, Yoon HS. Expression of OsTPX Gene Improves Cellular Redox Homeostasis and Photosynthesis Efficiency in Synechococcus elongatus PCC 7942. FRONTIERS IN PLANT SCIENCE 2018; 9:1848. [PMID: 30619416 PMCID: PMC6297720 DOI: 10.3389/fpls.2018.01848] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 11/28/2018] [Indexed: 06/09/2023]
Abstract
Cyanobacterial 2-Cys peroxiredoxin (thioredoxin peroxidase, TPX) comprises a family of thiol antioxidant enzymes critically involved in cell survival under oxidative stress. In our previous study, a putative TPX was identified using a proteomics analysis of rice (Oryza sativa L. japonica, OsTPX) seedlings exposed to oxidative stress. This OsTPX gene is structurally similar to the Synechococcus elongatus TPX gene in the highly conserved redox-active disulfide bridge (Cys114, Cys236) and other highly conserved regions. In the present study, the OsTPX gene was cloned into rice plants and S. elongatus PCC 7942 strain to study hydrogen peroxide (H2O2) stress responses. The OsTPX gene expression was confirmed using semi-quantitative RT-PCR and western blot analysis. The OsTPX gene expression increased growth under oxidative stress by decreasing reactive oxygen species and malondialdehyde level. Additionally, the OsTPX gene expression in S. elongatus PCC 7942 (OT) strain exhibited a reduced loss of chlorophyll and enhanced photosynthesis efficiency under H2O2 stress, thereby increasing biomass yields twofold compared with that of the control wild type (WT) strain. Furthermore, redox balance, ion homeostasis, molecular chaperone, and photosynthetic systems showed upregulation of some genes in the OT strain than in the WT strain by RNA-Seq analysis. Thus, OsTPX gene expression enhances oxidative stress tolerance by increasing cell defense regulatory networks through the cellular redox homeostasis in the rice plants and S. elongatus PCC 7942.
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Affiliation(s)
- Young-Saeng Kim
- Research Institute of Ulleung-do and Dok-do, Kyungpook National University, Daegu, South Korea
| | - Jin-Ju Kim
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu, South Korea
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, South Korea
| | - Seong-Im Park
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu, South Korea
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, South Korea
| | - Spencer Diamond
- Division of Biological Sciences, San Diego, La Jolla, CA, United States
| | - Joseph S. Boyd
- Division of Biological Sciences, San Diego, La Jolla, CA, United States
| | - Arnaud Taton
- Division of Biological Sciences, San Diego, La Jolla, CA, United States
| | - Il-Sup Kim
- Advanced Bio-Resource Research Center, Kyungpook National University, Daegu, South Korea
| | - James W. Golden
- Division of Biological Sciences, San Diego, La Jolla, CA, United States
| | - Ho-Sung Yoon
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu, South Korea
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, South Korea
- Advanced Bio-Resource Research Center, Kyungpook National University, Daegu, South Korea
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