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Giosa L, Collins PD, Sciolla M, Cerrone F, Di Blasi S, Macrì MM, Davicco L, Laguzzi A, Gorgonzola F, Penso R, Steinberg I, Muraccini M, Perboni A, Russotto V, Camporota L, Bellani G, Caironi P. Effects of CPAP and FiO 2 on respiratory effort and lung stress in early COVID-19 pneumonia: a randomized, crossover study. Ann Intensive Care 2023; 13:103. [PMID: 37847454 PMCID: PMC10581975 DOI: 10.1186/s13613-023-01202-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 10/06/2023] [Indexed: 10/18/2023] Open
Abstract
BACKGROUND in COVID-19 acute respiratory failure, the effects of CPAP and FiO2 on respiratory effort and lung stress are unclear. We hypothesize that, in the compliant lungs of early Sars-CoV-2 pneumonia, the application of positive pressure through Helmet-CPAP may not decrease respiratory effort, and rather worsen lung stress and oxygenation when compared to higher FiO2 delivered via oxygen masks. METHODS In this single-center (S.Luigi Gonzaga University-Hospital, Turin, Italy), randomized, crossover study, we included patients receiving Helmet-CPAP for early (< 48 h) COVID-19 pneumonia without additional cardiac or respiratory disease. Healthy subjects were included as controls. Participants were equipped with an esophageal catheter, a non-invasive cardiac output monitor, and an arterial catheter. The protocol consisted of a random sequence of non-rebreather mask (NRB), Helmet-CPAP (with variable positive pressure and FiO2) and Venturi mask (FiO2 0.5), each delivered for 20 min. Study outcomes were changes in respiratory effort (esophageal swing), total lung stress (dynamic + static transpulmonary pressure), gas-exchange and hemodynamics. RESULTS We enrolled 28 COVID-19 patients and 7 healthy controls. In all patients, respiratory effort increased from NRB to Helmet-CPAP (5.0 ± 3.7 vs 8.3 ± 3.9 cmH2O, p < 0.01). However, Helmet's pressure decreased by a comparable amount during inspiration (- 3.1 ± 1.0 cmH2O, p = 0.16), therefore dynamic stress remained stable (p = 0.97). Changes in static and total lung stress from NRB to Helmet-CPAP were overall not significant (p = 0.07 and p = 0.09, respectively), but showed high interpatient variability, ranging from - 4.5 to + 6.1 cmH2O, and from - 5.8 to + 5.7 cmH2O, respectively. All findings were confirmed in healthy subjects, except for an increase in dynamic stress (p < 0.01). PaO2 decreased from NRB to Helmet-CPAP with FiO2 0.5 (107 ± 55 vs 86 ± 30 mmHg, p < 0.01), irrespective of positive pressure levels (p = 0.64). Conversely, with Helmet's FiO2 0.9, PaO2 increased (p < 0.01), but oxygen delivery remained stable (p = 0.48) as cardiac output decreased (p = 0.02). When PaO2 fell below 60 mmHg with VM, respiratory effort increased proportionally (p < 0.01, r = 0.81). CONCLUSIONS In early COVID-19 pneumonia, Helmet-CPAP increases respiratory effort without altering dynamic stress, while the effects upon static and total stress are variable, requiring individual assessment. Oxygen masks with higher FiO2 provide better oxygenation with lower respiratory effort. Trial registration Retrospectively registered (13-May-2021): clinicaltrials.gov (NCT04885517), https://clinicaltrials.gov/ct2/show/NCT04885517 .
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Affiliation(s)
- Lorenzo Giosa
- Department of Critical Care Medicine, Guy's and St. Thomas' National Health Service Foundation Trust, St. Thomas' Hospital, Westminster Bridge Road, London, SE17EH, UK.
- Centre for Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, King's College London, London, UK.
| | - Patrick Duncan Collins
- Department of Critical Care Medicine, Guy's and St. Thomas' National Health Service Foundation Trust, St. Thomas' Hospital, Westminster Bridge Road, London, SE17EH, UK
| | - Martina Sciolla
- Department of Pulmonary Medicine, AOU S. Luigi Gonzaga, Orbassano, Turin, Italy
| | | | - Salvatore Di Blasi
- Department of Anesthesia and Critical Care, AOU S. Luigi Gonzaga, Orbassano, Turin, Italy
| | - Matteo Maria Macrì
- Department of Anesthesia and Critical Care, AOU S. Luigi Gonzaga, Orbassano, Turin, Italy
| | - Luca Davicco
- Department of Anesthesia and Critical Care, AOU S. Luigi Gonzaga, Orbassano, Turin, Italy
| | - Andrea Laguzzi
- Department of Anesthesia and Critical Care, AOU S. Luigi Gonzaga, Orbassano, Turin, Italy
| | - Fabiana Gorgonzola
- Department of Pulmonary Medicine, AOU S. Luigi Gonzaga, Orbassano, Turin, Italy
| | - Roberto Penso
- Department of Anesthesia and Critical Care, AOU S. Luigi Gonzaga, Orbassano, Turin, Italy
| | - Irene Steinberg
- Department of Surgical Sciences, University of Turin, Turin, Italy
- Department of Anaesthesia, Intensive Care and Emergency, Città della Salute e della Scienza University Hospital, Turin, Italy
| | | | - Alberto Perboni
- Department of Pulmonary Medicine, AOU S. Luigi Gonzaga, Orbassano, Turin, Italy
| | - Vincenzo Russotto
- Department of Anesthesia and Critical Care, AOU S. Luigi Gonzaga, Orbassano, Turin, Italy
- Department of Oncology, University of Turin, Turin, Italy
| | - Luigi Camporota
- Department of Critical Care Medicine, Guy's and St. Thomas' National Health Service Foundation Trust, St. Thomas' Hospital, Westminster Bridge Road, London, SE17EH, UK
- Centre for Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, King's College London, London, UK
| | - Giacomo Bellani
- Centre for Medical Sciences - CISMed, University of Trento, Trento, Italy
- Department of Anesthesia and Intensive Care, Santa Chiara Regional Hospital, APSS Trento, Trento, Italy
| | - Pietro Caironi
- Department of Anesthesia and Critical Care, AOU S. Luigi Gonzaga, Orbassano, Turin, Italy
- Department of Oncology, University of Turin, Turin, Italy
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Steensma AK, Shachar-Hill Y, Walker BJ. The carbon-concentrating mechanism of the extremophilic red microalga Cyanidioschyzon merolae. Photosynth Res 2023; 156:247-264. [PMID: 36780115 PMCID: PMC10154280 DOI: 10.1007/s11120-023-01000-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 01/27/2023] [Indexed: 05/03/2023]
Abstract
Cyanidioschyzon merolae is an extremophilic red microalga which grows in low-pH, high-temperature environments. The basis of C. merolae's environmental resilience is not fully characterized, including whether this alga uses a carbon-concentrating mechanism (CCM). To determine if C. merolae uses a CCM, we measured CO2 uptake parameters using an open-path infra-red gas analyzer and compared them to values expected in the absence of a CCM. These measurements and analysis indicated that C. merolae had the gas-exchange characteristics of a CCM-operating organism: low CO2 compensation point, high affinity for external CO2, and minimized rubisco oxygenation. The biomass δ13C of C. merolae was also consistent with a CCM. The apparent presence of a CCM in C. merolae suggests the use of an unusual mechanism for carbon concentration, as C. merolae is thought to lack a pyrenoid and gas-exchange measurements indicated that C. merolae primarily takes up inorganic carbon as carbon dioxide, rather than bicarbonate. We use homology to known CCM components to propose a model of a pH-gradient-based CCM, and we discuss how this CCM can be further investigated.
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Affiliation(s)
- Anne K Steensma
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
- Michigan State University - Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
| | - Yair Shachar-Hill
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
| | - Berkley J Walker
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA.
- Michigan State University - Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, USA.
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Giareta EP, Hauser-Davis RA, Abilhoa V, Wosnick N. Carbonic anhydrase in elasmobranchs and implications of the current climate change scenario. Comp Biochem Physiol A Mol Integr Physiol 2023; 281:111435. [PMID: 37086909 DOI: 10.1016/j.cbpa.2023.111435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 04/16/2023] [Accepted: 04/17/2023] [Indexed: 04/24/2023]
Abstract
The enzyme carbonic anhydrase (CA) has well-known functions in acid-base balance, respiratory gas exchange, and osmoregulation in teleost fishes. However, studies concerning the role of CA in elasmobranchs are still scarce. Therefore, the aim of this study is to present the current status of CA studies in sharks and rays, as well as to identify gaps and emerging needs, in order to guide future studies. This review is organized according to the main roles of CA, with further considerations on climate change and CA effects indicated as paramount, as strategies in the face of climate change can be crucial for species response. The literature review revealed a reduction in publications on CA over the years. In addition, a historical research differentiation is noted, where the first assessments on the subject addressed investigations on basic CA functions, while the most recent studies present a comparative approach among species as well as interdisciplinary discussions, such as ecology and phylogeny. Considering that most elasmobranchs are threatened, future studies should prioritize non-lethal methodologies, in addition to expanding studies to climate change effects on CA.
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Affiliation(s)
| | - Rachel Ann Hauser-Davis
- Laboratório de Avaliação e Promoção da Saúde Ambiental, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil
| | - Vinícius Abilhoa
- Programa de Pós-Graduação em Zoologia, Universidade Federal do Paraná, Curitiba, Brazil
| | - Natascha Wosnick
- Programa de Pós-Graduação em Zoologia, Universidade Federal do Paraná, Curitiba, Brazil
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Soares C, Pereira R, Martins M, Tamagnini P, Serôdio J, Moutinho-Pereira J, Cunha A, Fidalgo F. Glyphosate-dependent effects on photosynthesis of Solanum lycopersicum L.-An ecophysiological, ultrastructural and molecular approach. J Hazard Mater 2020; 398:122871. [PMID: 32450466 DOI: 10.1016/j.jhazmat.2020.122871] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 04/24/2020] [Accepted: 05/04/2020] [Indexed: 06/11/2023]
Abstract
This study aimed to assess the toxicity of glyphosate (GLY; 0, 10, 20 and 30 mg kg-1) in Solanum lycopersicum L., particularly focusing on the photosynthetic metabolism. By combining ecophysiological, ultrastructural, biochemical and molecular tools, the results revealed that the exposure of tomato plants to GLY led to alterations in leaf water balance regulation [increasing stomatal conductance (gs) and decreasing water use efficiency (WUEi) at higher concentrations] and induced slight alterations in the structural integrity of cells, mainly in chloroplasts, accompanied by a loss of cell viability. Moreover, the transcriptional and biochemical control of several photosynthetic-related parameters was reduced upon GLY exposure. However, in vivo chlorophyll fluorometry and IRGA gas-exchange studies revealed that the photosynthetic yield of S. lycopersicum was not repressed by GLY. Overall, GLY impacts cellular and subcellular homeostasis (by affecting chloroplast structure, reducing photosynthetic pigments and inhibiting photosynthetic-related genes transcription), and leaf structure, but is not reducing the carbon flow on a leaf area basis. Altogether, these results suggest a trade-off effect in which GLY-induced toxicity is compensated by a higher photosynthetic activity related to GLY-induced dysfunction in gs and an increase in mesophyll thickness/density, allowing the viable leaf cells to maintain their photosynthetic capacity.
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Affiliation(s)
- Cristiano Soares
- GreenUPorto - Sustainable Agrifood Production Research Centre, Department of Biology, Faculty of Sciences of University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal.
| | - Ruth Pereira
- GreenUPorto - Sustainable Agrifood Production Research Centre, Department of Biology, Faculty of Sciences of University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Maria Martins
- GreenUPorto - Sustainable Agrifood Production Research Centre, Department of Biology, Faculty of Sciences of University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Paula Tamagnini
- Bioengineering and Synthetic Microbiology Group, i3S - Instituto de Investigação e Inovação em Saúde, University of Porto, Porto, Portugal; IBMC - Instituto de Biologia Celular e Molecular, University of Porto, Porto, Portugal; Biology Department, Faculty of Sciences of University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - João Serôdio
- Biology Department and CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal
| | - José Moutinho-Pereira
- CITAB - Centre for the Research and Technology of Agro-Environmental and Biological Sciences, Universidade de Trás-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal
| | - Ana Cunha
- Biology Department & CITAB - Centre for the Research and Technology of Agro-Environmental and Biological Sciences, School of Sciences, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Fernanda Fidalgo
- GreenUPorto - Sustainable Agrifood Production Research Centre, Department of Biology, Faculty of Sciences of University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
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Salter WT, Gilbert ME, Buckley TN. A multiplexed gas exchange system for increased throughput of photosynthetic capacity measurements. Plant Methods 2018; 14:80. [PMID: 30214467 PMCID: PMC6131801 DOI: 10.1186/s13007-018-0347-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 09/05/2018] [Indexed: 05/22/2023]
Abstract
BACKGROUND Existing methods for directly measuring photosynthetic capacity (Amax) have low throughput, which creates a key bottleneck for pre-breeding and ecological research. Currently available commercial leaf gas exchange systems are not designed to maximize throughput, on either a cost or time basis. RESULTS We present a novel multiplexed semi-portable gas exchange system, OCTOflux, that can measure Amax with approximately 4-7 times the throughput of commercial devices, despite a lower capital cost. The main time efficiency arises from having eight leaves simultaneously acclimate to saturating CO2 and high light levels; the long acclimation periods for each leaf (13.8 min on average in this study) thus overlap to a large degree, rather than occurring sequentially. The cost efficiency arises partly from custom-building the system and thus avoiding commercial costs like distribution, marketing and profit, and partly from optimizing the system's design for Amax throughput rather than flexibility for other types of measurements. CONCLUSION Throughput for Amax measurements can be increased greatly, on both a cost and time basis, by multiplexing gas streams from several leaf chambers connected to a single gas analyzer. This can help overcome the bottleneck in breeding and ecological research posed by limited phenotyping throughput for Amax.
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Affiliation(s)
- William T. Salter
- School of Life and Environmental Sciences, Sydney Institute of Agriculture, The University of Sydney, Sydney, NSW Australia
| | - Matthew E. Gilbert
- Department of Plant Sciences, University of California, Davis, Davis, CA 95616 USA
| | - Thomas N. Buckley
- Department of Plant Sciences, University of California, Davis, Davis, CA 95616 USA
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Holtum JAM, Hancock LP, Edwards EJ, Winter K. Optional use of CAM photosynthesis in two C 4 species, Portulaca cyclophylla and Portulaca digyna. J Plant Physiol 2017; 214:91-96. [PMID: 28511087 DOI: 10.1016/j.jplph.2017.01.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 01/28/2017] [Accepted: 01/30/2017] [Indexed: 06/07/2023]
Abstract
Low levels of crassulacean acid metabolism (CAM) are demonstrated in two species with C4 photosynthesis, Portulaca cyclophylla and P. digyna. The expression of CAM in P. cyclophylla and P. digyna is facultative, i.e. optional. Well-watered plants did not accumulate acid at night and exhibited gas-exchange patterns consistent with C4 photosynthesis. CAM-type nocturnal acidification was reversible in that it was induced following drought and lost when droughted plants were rewatered. In P. cyclophylla, droughting was accompanied by a small but discernible net uptake of CO2 during the dark, whereas in P. digyna, net CO2 exchange at night approached the CO2 compensation point but did not transition beyond it. This report brings the number of known C4 species with a capacity for expressing CAM to six. All are species of Portulaca. The observation of CAM in P. cyclophylla and P. digyna is the first for species in the opposite-leaved (OL) Portulacelloid-anatomy lineage of Portulaca and for the Australian clade therein. The other four species are within the alternate-leaved (AL) lineage, in the Atriploid-anatomy Oleracea and the Pilosoid-anatomy Pilosa clades. Studies of the evolutionary origins of C4 and CAM in Portulaca will benefit from a more wide-range survey of CAM across its species, particularly in the C3-C4 intermediate-containing Cryptopetala clade.
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Affiliation(s)
- Joseph A M Holtum
- Centre for Tropical Biodiversity and Climate Change, College of Science and Engineering, James Cook University, Townsville 4811, Queensland, Australia; Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancón, Panama.
| | - Lillian P Hancock
- Department of Ecology and Evolutionary Biology, Brown University, Box G-W, Providence RI 02912, USA.
| | - Erika J Edwards
- Department of Ecology and Evolutionary Biology, Brown University, Box G-W, Providence RI 02912, USA.
| | - Klaus Winter
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancón, Panama.
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Scafaro AP, Negrini ACA, O’Leary B, Rashid FAA, Hayes L, Fan Y, Zhang Y, Chochois V, Badger MR, Millar AH, Atkin OK. The combination of gas-phase fluorophore technology and automation to enable high-throughput analysis of plant respiration. Plant Methods 2017; 13:16. [PMID: 28344635 PMCID: PMC5361846 DOI: 10.1186/s13007-017-0169-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 03/17/2017] [Indexed: 05/18/2023]
Abstract
BACKGROUND Mitochondrial respiration in the dark (Rdark) is a critical plant physiological process, and hence a reliable, efficient and high-throughput method of measuring variation in rates of Rdark is essential for agronomic and ecological studies. However, currently methods used to measure Rdark in plant tissues are typically low throughput. We assessed a high-throughput automated fluorophore system of detecting multiple O2 consumption rates. The fluorophore technique was compared with O2-electrodes, infrared gas analysers (IRGA), and membrane inlet mass spectrometry, to determine accuracy and speed of detecting respiratory fluxes. RESULTS The high-throughput fluorophore system provided stable measurements of Rdark in detached leaf and root tissues over many hours. High-throughput potential was evident in that the fluorophore system was 10 to 26-fold faster per sample measurement than other conventional methods. The versatility of the technique was evident in its enabling: (1) rapid screening of Rdark in 138 genotypes of wheat; and, (2) quantification of rarely-assessed whole-plant Rdark through dissection and simultaneous measurements of above- and below-ground organs. DISCUSSION Variation in absolute Rdark was observed between techniques, likely due to variation in sample conditions (i.e. liquid vs. gas-phase, open vs. closed systems), indicating that comparisons between studies using different measuring apparatus may not be feasible. However, the high-throughput protocol we present provided similar values of Rdark to the most commonly used IRGA instrument currently employed by plant scientists. Together with the greater than tenfold increase in sample processing speed, we conclude that the high-throughput protocol enables reliable, stable and reproducible measurements of Rdark on multiple samples simultaneously, irrespective of plant or tissue type.
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Affiliation(s)
- Andrew P. Scafaro
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT 2601 Australia
- Bayer CropScience SA-NV, Technologiepark 38, 9052 Gent (Zwijnaarde), Belgium
| | - A. Clarissa A. Negrini
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT 2601 Australia
| | - Brendan O’Leary
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT 2601 Australia
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 Australia
| | - F. Azzahra Ahmad Rashid
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT 2601 Australia
| | - Lucy Hayes
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT 2601 Australia
| | - Yuzhen Fan
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT 2601 Australia
| | - You Zhang
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT 2601 Australia
| | - Vincent Chochois
- ARC Centre of Excellence for Translational Photosynthesis, Building 134, The Australian National University, Canberra, ACT 2601 Australia
| | - Murray R. Badger
- ARC Centre of Excellence for Translational Photosynthesis, Building 134, The Australian National University, Canberra, ACT 2601 Australia
| | - A. Harvey Millar
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 Australia
| | - Owen K. Atkin
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT 2601 Australia
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Scafaro AP, Negrini ACA, O'Leary B, Rashid FAA, Hayes L, Fan Y, Zhang Y, Chochois V, Badger MR, Millar AH, Atkin OK. The combination of gas-phase fluorophore technology and automation to enable high-throughput analysis of plant respiration. Plant Methods 2017; 13:16. [PMID: 28344635 DOI: 10.1186/s13007-017-0169-163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 03/17/2017] [Indexed: 05/22/2023]
Abstract
BACKGROUND Mitochondrial respiration in the dark (Rdark) is a critical plant physiological process, and hence a reliable, efficient and high-throughput method of measuring variation in rates of Rdark is essential for agronomic and ecological studies. However, currently methods used to measure Rdark in plant tissues are typically low throughput. We assessed a high-throughput automated fluorophore system of detecting multiple O2 consumption rates. The fluorophore technique was compared with O2-electrodes, infrared gas analysers (IRGA), and membrane inlet mass spectrometry, to determine accuracy and speed of detecting respiratory fluxes. RESULTS The high-throughput fluorophore system provided stable measurements of Rdark in detached leaf and root tissues over many hours. High-throughput potential was evident in that the fluorophore system was 10 to 26-fold faster per sample measurement than other conventional methods. The versatility of the technique was evident in its enabling: (1) rapid screening of Rdark in 138 genotypes of wheat; and, (2) quantification of rarely-assessed whole-plant Rdark through dissection and simultaneous measurements of above- and below-ground organs. DISCUSSION Variation in absolute Rdark was observed between techniques, likely due to variation in sample conditions (i.e. liquid vs. gas-phase, open vs. closed systems), indicating that comparisons between studies using different measuring apparatus may not be feasible. However, the high-throughput protocol we present provided similar values of Rdark to the most commonly used IRGA instrument currently employed by plant scientists. Together with the greater than tenfold increase in sample processing speed, we conclude that the high-throughput protocol enables reliable, stable and reproducible measurements of Rdark on multiple samples simultaneously, irrespective of plant or tissue type.
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Affiliation(s)
- Andrew P Scafaro
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT 2601 Australia
- Bayer CropScience SA-NV, Technologiepark 38, 9052 Gent (Zwijnaarde), Belgium
| | - A Clarissa A Negrini
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT 2601 Australia
| | - Brendan O'Leary
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT 2601 Australia
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 Australia
| | - F Azzahra Ahmad Rashid
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT 2601 Australia
| | - Lucy Hayes
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT 2601 Australia
| | - Yuzhen Fan
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT 2601 Australia
| | - You Zhang
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT 2601 Australia
| | - Vincent Chochois
- ARC Centre of Excellence for Translational Photosynthesis, Building 134, The Australian National University, Canberra, ACT 2601 Australia
| | - Murray R Badger
- ARC Centre of Excellence for Translational Photosynthesis, Building 134, The Australian National University, Canberra, ACT 2601 Australia
| | - A Harvey Millar
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 Australia
| | - Owen K Atkin
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT 2601 Australia
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