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Guermazi W, Masmoudi S, Trabelsi NA, Gammoudi S, Ayadi H, Morant-Manceau A, Hotos GN. Physiological and Biochemical Responses in Microalgae Dunaliella salina, Cylindrotheca closterium and Phormidium versicolor NCC466 Exposed to High Salinity and Irradiation. Life (Basel) 2023; 13:life13020313. [PMID: 36836671 PMCID: PMC9961930 DOI: 10.3390/life13020313] [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: 12/16/2022] [Revised: 01/16/2023] [Accepted: 01/19/2023] [Indexed: 01/24/2023] Open
Abstract
Dunaliella salina (Chlorophyceae), Phormidium versicolor (Cyanophyceae), and Cylindrotheca closterium (Bacillariophyceae) were isolated from three ponds in the solar saltern of Sfax (Tunisia). Growth, pigment contents, and photosynthetic and antioxidant enzyme activities were measured under controlled conditions of three light levels (300, 500, and 1000 µmol photons m-2 s-1) and three NaCl concentrations (40, 80, and 140 g L-1). The highest salinity reduced the growth of D. salina and P. versicolor NCC466 and strongly inhibited that of C. closterium. According to ΦPSII values, the photosynthetic apparatus of P. versicolor was stimulated by increasing salinity, whereas that of D. salina and C. closterium was decreased by irradiance rise. The production of carotenoids in D. salina and P. versicolor was stimulated when salinity and irradiance increased, whereas it decreased in the diatom. Catalase (CAT), Superoxide dismutase (SOD), and Ascorbate peroxidase (APX) activities were only detected when the three species were cultivated under E1000. The antioxidant activity of carotenoids could compensate for the low antioxidant enzyme activity measured in D. salina. Salinity and irradiation levels interact with the physiology of three species that have mechanisms of more or less effective stress resistance, hence different resistance to environmental stresses according to the species. Under these stress-controlled conditions, P. versicolor and C. closterium strains could provide promising sources of extremolyte for several purposes.
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Affiliation(s)
- Wassim Guermazi
- Laboratory of Marine Biodiversity and Environment (LR18ES/30), University of Sfax, Sfax CP 3000, Tunisia
| | - Salma Masmoudi
- Laboratory of Marine Biodiversity and Environment (LR18ES/30), University of Sfax, Sfax CP 3000, Tunisia
- LUNAM, Laboratoire Mer, Molécules, Santé (EA 2160), Université du Maine, Avenue Olivier Messiaen, CEDEX 9, 72085 Le Mans, France
| | - Neila Annabi Trabelsi
- Laboratory of Marine Biodiversity and Environment (LR18ES/30), University of Sfax, Sfax CP 3000, Tunisia
| | - Sana Gammoudi
- Laboratory of Marine Biodiversity and Environment (LR18ES/30), University of Sfax, Sfax CP 3000, Tunisia
| | - Habib Ayadi
- Laboratory of Marine Biodiversity and Environment (LR18ES/30), University of Sfax, Sfax CP 3000, Tunisia
| | - Annick Morant-Manceau
- LUNAM, Laboratoire Mer, Molécules, Santé (EA 2160), Université du Maine, Avenue Olivier Messiaen, CEDEX 9, 72085 Le Mans, France
| | - George N. Hotos
- Plankton Culture Laboratory, Department of Fisheries and Aquaculture, University of Patras, 30200 Messolonghi, Greece
- Correspondence:
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Kang JS, Kim S, Kang J, Joo H, Jang J, Jo K, Park S, Kim HI, Yoo SJ, Yoon J, Sung YE, Hatton TA. Surface Electrochemistry of Carbon Electrodes and Faradaic Reactions in Capacitive Deionization. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:12602-12612. [PMID: 35998306 DOI: 10.1021/acs.est.2c03913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Recent advances in electrochemical desalination techniques have paved way for utilization of saline water. In particular, capacitive deionization (CDI) enables removal of salts with high energy efficiency and economic feasibility, while its applicability has been challenged by degradation of carbon electrodes in long-term operations. Herein, we report a thorough investigation on the surface electrochemistry of carbon electrodes and Faradaic reactions that are responsible for stability issues of CDI systems. By using bare and membrane CDI (MCDI) as model systems, we identified various electrochemical reactions of carbon electrodes with water or oxygen, with thermodynamics and kinetics governed by the electrode potential and pH. As a result, a complete overview of the Faradaic reactions taking place in CDI was constructed by tracing the physicochemical changes occurring in CDI and MCDI systems.
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Affiliation(s)
- Jin Soo Kang
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- School of Chemical and Biological Engineering and Institute of Chemical Processes (ICP), Seoul National University, Seoul 08826, Republic of Korea
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- Department of Energy Systems Engineering, Seoul National University, Seoul 08826, Republic of Korea
- Department of Energy Resources Engineering and Research Institute of Energy and Resources, Seoul National University, Seoul 08826, Republic of Korea
| | - Seoni Kim
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- School of Chemical and Biological Engineering and Institute of Chemical Processes (ICP), Seoul National University, Seoul 08826, Republic of Korea
| | - Jiho Kang
- School of Chemical and Biological Engineering and Institute of Chemical Processes (ICP), Seoul National University, Seoul 08826, Republic of Korea
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
| | - Hwajoo Joo
- School of Chemical and Biological Engineering and Institute of Chemical Processes (ICP), Seoul National University, Seoul 08826, Republic of Korea
| | - Junghwan Jang
- School of Chemical and Biological Engineering and Institute of Chemical Processes (ICP), Seoul National University, Seoul 08826, Republic of Korea
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
| | - Kyusik Jo
- School of Chemical and Biological Engineering and Institute of Chemical Processes (ICP), Seoul National University, Seoul 08826, Republic of Korea
| | - Subin Park
- School of Chemical and Biological Engineering and Institute of Chemical Processes (ICP), Seoul National University, Seoul 08826, Republic of Korea
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- Center for Hydrogen·Fuel Cell Research, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Hyoung-Il Kim
- Department of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Sung Jong Yoo
- Center for Hydrogen·Fuel Cell Research, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Jeyong Yoon
- School of Chemical and Biological Engineering and Institute of Chemical Processes (ICP), Seoul National University, Seoul 08826, Republic of Korea
| | - Yung-Eun Sung
- School of Chemical and Biological Engineering and Institute of Chemical Processes (ICP), Seoul National University, Seoul 08826, Republic of Korea
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
| | - T Alan Hatton
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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Human-Induced Sharp Salinity Changes in the World’s Largest Hypersaline Lagoon Bay Sivash (Crimea) and Their Effects on the Ecosystem. WATER 2022. [DOI: 10.3390/w14030403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Lakes and lagoons play an important role worldwide, and salinity fluctuations significantly affect their ecosystems. Bay Sivash, the world’s largest hypersaline water body, underwent a sharp change in salinity, induced by the closing of the North Crimean Canal. To monitor a shift in the ecosystem, a study was carried out from 2014 to 2020 at 15 sites of the lagoon. Since the closure of the canal, the average salinity increased from 22 g L−1 (2013) to 94 g L−1 (2020). Suspended solids and dissolved organic matter also increased. When salinity increased above 50 g L−1, the number of taxa significantly decreased; this was a negative linear relation. The increase in salinity significantly changed the structure of zooplankton and benthos. The most dramatic changes occurred with the salinity increase from 25 to 70 g L−1. Chironomidae larvae numbers began to increase greatly in the ecosystem of the bay, and since 2014, they have rapidly increased their contribution to the abundance of benthos and plankton. The concentration of benthic–planktonic species increased in plankton, in particular, in Harpacticoida and Chironomidae. At salinity above 80–90 g L−1, nauplii and adult brine shrimp appeared to become abundant in plankton and benthos. The transit of the ecosystem to a new alternative state occurred.
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Torregrosa-Crespo J, Pire C, Bergaust L, Martínez-Espinosa RM. Haloferax mediterranei, an Archaeal Model for Denitrification in Saline Systems, Characterized Through Integrated Physiological and Transcriptional Analyses. Front Microbiol 2020; 11:768. [PMID: 32390995 PMCID: PMC7188791 DOI: 10.3389/fmicb.2020.00768] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 03/31/2020] [Indexed: 11/13/2022] Open
Abstract
Haloferax mediterranei (R4) belongs to the group of halophilic archaea, one of the predominant microbial populations in hypersaline environments. In these ecosystems, the low availability of oxygen pushes the microbial inhabitants toward anaerobic pathways and the presence of N-oxyanions favor denitrification. In a recent study comparing three Haloferax species carrying dissimilatory N-oxide reductases, H. mediterranei showed promise as a future model for archaeal denitrification. This work further explores the respiratory physiology of this haloarchaeon when challenged with ranges of nitrite and nitrate concentrations and at neutral or sub-neutral pH during the transition to anoxia. Moreover, to begin to understand the transcriptional regulation of N-oxide reductases, detailed gas kinetics was combined with gene expression analyses at high resolution. The results show that H. mediterranei has an expression pattern similar to that observed in the bacterial Domain, well-coordinated at low concentrations of N-oxyanions. However, it could only sustain a few generations of exponential anaerobic growth, apparently requiring micro-oxic conditions for de novo synthesis of denitrification enzymes. This is the first integrated study within this field of knowledge in haloarchaea and Archaea in general, and it sheds lights on denitrification in salty environments.
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Affiliation(s)
- Javier Torregrosa-Crespo
- Department of Agrochemistry and Biochemistry, Faculty of Science, University of Alicante, Alicante, Spain
| | - Carmen Pire
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Linda Bergaust
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
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Zhang SX, Jiang R, Yun N, Peng R, Chai XS. A simple high-throughput headspace gas chromatographic method for the determination of dissolved oxygen in aqueous samples. J Chromatogr A 2019; 1608:460399. [PMID: 31371200 DOI: 10.1016/j.chroma.2019.460399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/22/2019] [Accepted: 07/23/2019] [Indexed: 10/26/2022]
Abstract
This paper reports on a headspace gas chromatographic method (HS-GC) for the accurate determination of dissolved oxygen (DO) in domestic and industrial wastewater. It was based on GC measurement of oxygen in the headspace gas that is released from the dissolved oxygen in a liquid sample in a closed vial. The results show that the relative standard deviation of the method in quintuplicate testing was < 2.0% and the relative differences of results were less than 4.0% for the real river water samples when compared with the widely used reference method (the electrode method); The linear range of the method is about 0-9.0 mg/L with the limit of detection of 0.30 mg/L. The present method is simple in both sample preparation and method calibration. It is particularly efficient in the batch testing mode. Overall, the method is more reliable than the current reference method when used with samples from a wide range of sources.
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Affiliation(s)
- Shu-Xin Zhang
- School of Chemical Technology, Guangdong Industry Polytechnic, Guangzhou, 510300, China
| | - Ran Jiang
- The Pearl River Hydraulic Research Institute, Guangzhou, 510611, China
| | - Na Yun
- School of Chemical Technology, Guangdong Industry Polytechnic, Guangzhou, 510300, China
| | - Rong Peng
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, 510640, China
| | - Xin-Sheng Chai
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, 510640, China.
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6
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DiLoreto ZA, Bontognali TRR, Al Disi ZA, Al-Kuwari HAS, Williford KH, Strohmenger CJ, Sadooni F, Palermo C, Rivers JM, McKenzie JA, Tuite M, Dittrich M. Microbial community composition and dolomite formation in the hypersaline microbial mats of the Khor Al-Adaid sabkhas, Qatar. Extremophiles 2019; 23:201-218. [PMID: 30617527 DOI: 10.1007/s00792-018-01074-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 12/29/2018] [Indexed: 11/24/2022]
Abstract
The Khor Al-Adaid sabkha in Qatar is among the rare extreme environments on Earth where it is possible to study the formation of dolomite-a carbonate mineral whose origin remains unclear and has been hypothetically linked to microbial activity. By combining geochemical measurements with microbiological analysis, we have investigated the microbial mats colonizing the intertidal areas of sabhka. The main aim of this study was to identify communities and conditions that are favorable for dolomite formation. We inspected and sampled two locations. The first site was colonized by microbial mats that graded vertically from photo-oxic to anoxic conditions and were dominated by cyanobacteria. The second site, with higher salinity, had mats with an uppermost photo-oxic layer dominated by filamentous anoxygenic photosynthetic bacteria (FAPB), which potentially act as a protective layer against salinity for cyanobacterial species within the deeper layers. Porewater in the uppermost layers of the both investigated microbial mats was supersaturated with respect to dolomite. Corresponding to the variation of the microbial community's vertical structure, a difference in crystallinity and morphology of dolomitic phases was observed: dumbbell-shaped proto-dolomite in the mats dominated by cyanobacteria and rhombohedral ordered-dolomite in the mat dominated by FAPB.
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Affiliation(s)
- Zach A DiLoreto
- Department of Physical & Environmental Sciences, University of Toronto Scarborough, 1065 Military Trail, Toronto, ON, M1C 1A4, Canada
| | - Tomaso R R Bontognali
- Department of Earth Sciences, ETH Zurich, Zurich, Switzerland
- Qatar University, Doha, Qatar
- Space Exploration Institute, Neuchatel, Switzerland
| | | | | | - Kenneth H Williford
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | | | - Christine Palermo
- Department of Physical & Environmental Sciences, University of Toronto Scarborough, 1065 Military Trail, Toronto, ON, M1C 1A4, Canada
| | | | | | - Michael Tuite
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Maria Dittrich
- Department of Physical & Environmental Sciences, University of Toronto Scarborough, 1065 Military Trail, Toronto, ON, M1C 1A4, Canada.
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7
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Increased production of polyhydroxyalkanoates with controllable composition and consistent material properties by fed-batch fermentation. Biochem Eng J 2019. [DOI: 10.1016/j.bej.2018.10.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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8
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Torregrosa-Crespo J, Pire C, Martínez-Espinosa RM, Bergaust L. Denitrifying haloarchaea within the genus Haloferax display divergent respiratory phenotypes, with implications for their release of nitrogenous gases. Environ Microbiol 2018; 21:427-436. [PMID: 30421557 DOI: 10.1111/1462-2920.14474] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 11/05/2018] [Indexed: 11/30/2022]
Abstract
Haloarchaea are extremophiles, generally thriving at high temperatures and salt concentrations, thus, with limited access to oxygen. As a strategy to maintain a respiratory metabolism, many halophilic archaea are capable of denitrification. Among them are members of the genus Haloferax, which are abundant in saline/hypersaline environments. Three reported haloarchaeal denitrifiers, Haloferax mediterranei, Haloferax denitrificans and Haloferax volcanii, were characterized with respect to their denitrification phenotype. A semi-automatic incubation system was used to monitor the depletion of electron acceptors and accumulation of gaseous intermediates in batch cultures under a range of conditions. Out of the species tested, only H. mediterranei was able to consistently reduce all available N-oxyanions to N2 , while the other two released significant amounts of NO and N2 O, which affect tropospheric and stratospheric chemistries respectively. The prevalence and magnitude of hypersaline ecosystems are on the rise due to climate change and anthropogenic activity. Thus, the biology of halophilic denitrifiers is inherently interesting, due to their contribution to the global nitrogen cycle, and potential application in bioremediation. This work is the first detailed physiological study of denitrification in haloarchaea, and as such a seed for our understanding of the drivers of nitrogen turnover in hypersaline systems.
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Affiliation(s)
- Javier Torregrosa-Crespo
- Departamento de Agroquímica y Bioquímica, División de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Alicante, Carretera San Vicente del Raspeig s/n - 03690 San Vicente del Raspeig, Alicante, Spain
| | - Carmen Pire
- Departamento de Agroquímica y Bioquímica, División de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Alicante, Carretera San Vicente del Raspeig s/n - 03690 San Vicente del Raspeig, Alicante, Spain
| | - Rosa María Martínez-Espinosa
- Departamento de Agroquímica y Bioquímica, División de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Alicante, Carretera San Vicente del Raspeig s/n - 03690 San Vicente del Raspeig, Alicante, Spain
| | - Linda Bergaust
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences. Chr. M, Falsens vei 1 - 1430, Ås, Norway
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Al-Saedi HM, Archer AJ, Ward J. Dynamical density-functional-theory-based modeling of tissue dynamics: Application to tumor growth. Phys Rev E 2018; 98:022407. [PMID: 30253518 DOI: 10.1103/physreve.98.022407] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Indexed: 06/08/2023]
Abstract
We present a theoretical framework based on an extension of dynamical density-functional theory (DDFT) for describing the structure and dynamics of cells in living tissues and tumors. DDFT is a microscopic statistical mechanical theory for the time evolution of the density distribution of interacting many-particle systems. The theory accounts for cell-pair interactions, different cell types, phenotypes, and cell birth and death processes (including cell division), to provide a biophysically consistent description of processes bridging across the scales, including describing the tissue structure down to the level of the individual cells. Analysis of the model is presented for single-species and two-species cases, the latter aimed at describing competition between tumor and healthy cells. In suitable parameter regimes, model results are consistent with biological observations. Of particular note, divergent tumor growth behavior, mirroring metastatic and benign growth characteristics, are shown to be dependent on the cell-pair-interaction parameters.
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Affiliation(s)
- Hayder M Al-Saedi
- Department of Mathematical Sciences, Loughborough University, Loughborough LE11 3TU, United Kingdom
- Department of Mathematical Sciences, Baghdad University, Baghdad, Iraq
| | - Andrew J Archer
- Department of Mathematical Sciences, Loughborough University, Loughborough LE11 3TU, United Kingdom
| | - John Ward
- Department of Mathematical Sciences, Loughborough University, Loughborough LE11 3TU, United Kingdom
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10
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Simillion H, Van den Steen N, Terryn H, Deconinck J. Geometry influence on corrosion in dynamic thin film electrolytes. Electrochim Acta 2016. [DOI: 10.1016/j.electacta.2016.04.072] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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11
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Sepunaru L, Sokolov SV, Holter J, Young NP, Compton RG. Electrochemical Red Blood Cell Counting: One at a Time. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201605310] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Lior Sepunaru
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory; University of Oxford; South Parks Road Oxford OX1 3QZ UK
| | - Stanislav V. Sokolov
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory; University of Oxford; South Parks Road Oxford OX1 3QZ UK
| | | | - Neil P. Young
- Department of Materials; University of Oxford; OX1 3PH UK
| | - Richard G. Compton
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory; University of Oxford; South Parks Road Oxford OX1 3QZ UK
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12
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Sepunaru L, Sokolov SV, Holter J, Young NP, Compton RG. Electrochemical Red Blood Cell Counting: One at a Time. Angew Chem Int Ed Engl 2016; 55:9768-71. [DOI: 10.1002/anie.201605310] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Indexed: 11/05/2022]
Affiliation(s)
- Lior Sepunaru
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory; University of Oxford; South Parks Road Oxford OX1 3QZ UK
| | - Stanislav V. Sokolov
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory; University of Oxford; South Parks Road Oxford OX1 3QZ UK
| | | | - Neil P. Young
- Department of Materials; University of Oxford; OX1 3PH UK
| | - Richard G. Compton
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory; University of Oxford; South Parks Road Oxford OX1 3QZ UK
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Probing Saltern Brines with an Oxygen Electrode: What Can We Learn about the Community Metabolism in Hypersaline Systems? Life (Basel) 2016; 6:life6020023. [PMID: 27338478 PMCID: PMC4931460 DOI: 10.3390/life6020023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 06/02/2016] [Accepted: 06/06/2016] [Indexed: 11/23/2022] Open
Abstract
We have explored the use of optical oxygen electrodes to study oxygenic photosynthesis and heterotrophic activities in crystallizer brines of the salterns in Eilat, Israel. Monitoring oxygen uptake rates in the dark enables the identification of organic substrates that are preferentially used by the community. Addition of glycerol (the osmotic solute synthesized by Dunaliella) or dihydroxyacetone (produced from glycerol by Salinibacter) enhanced respiration rates. Pyruvate, produced from glycerol or from some sugars by certain halophilic Archaea also stimulated community respiration. Fumarate had a sparing effect on respiration, possibly as many halophilic Archaea can use fumarate as a terminal electron acceptor in respiration. Calculating the photosynthetic activity of Dunaliella by monitoring oxygen concentration changes during light/dark incubations is not straightforward as light also affects respiration of some halophilic Archaea and Bacteria due to action of light-driven proton pumps. When illuminated, community respiration of brine samples in which oxygenic photosynthesis was inhibited by DCMU decreased by ~40%. This effect was interpreted as the result of competition between two energy yielding systems: the bacteriorhodopsin proton pump and the respiratory chain of the prokaryotes. These findings have important implications for the interpretation of other published data on photosynthetic and respiratory activities in hypersaline environments.
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14
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Braga Goncalves I, Ahnesjö I, Kvarnemo C. Evolutionary ecology of pipefish brooding structures: embryo survival and growth do not improve with a pouch. Ecol Evol 2016; 6:3608-3620. [PMID: 27231531 PMCID: PMC4864203 DOI: 10.1002/ece3.2139] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/16/2016] [Accepted: 03/21/2016] [Indexed: 12/03/2022] Open
Abstract
For animals that reproduce in water, many adaptations in life‐history traits such as egg size, parental care, and behaviors that relate to embryo oxygenation are still poorly understood. In pipefishes, seahorses and seadragons, males care for the embryos either in some sort of brood pouch, or attached ventrally to the skin on their belly or tail. Typically, egg size is larger in the brood pouch group and it has been suggested that oxygen supplied via the pouch buffers the developing embryos against hypoxia and as such is an adaptation that has facilitated the evolution of larger eggs. Here, using four pipefish species, we tested whether the presence or absence of brood pouch relates to how male behavior, embryo size, and survival are affected by hypoxia, with normoxia as control. Two of our studied species Entelurus aequoreus and Nerophis ophidion (both having small eggs) have simple ventral attachment of eggs onto the male trunk, and the other two, Syngnathus typhle (large eggs) and S. rostellatus (small eggs), have fully enclosed brood pouches on the tail. Under hypoxia, all species showed lower embryo survival, while species with brood pouches suffered greater embryo mortality compared to pouchless species, irrespective of oxygen treatment. Behaviorally, species without pouches spent more time closer to the surface, possibly to improve oxygenation. Overall, we found no significant benefits of brood pouches in terms of embryo survival and size under hypoxia. Instead, our results suggest negative effects of large egg size, despite the protection of brood pouches.
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Affiliation(s)
- Ines Braga Goncalves
- Department of Evolutionary Biology and Environmental Studies, Animal Behaviour University of Zurich Winterthurerstrasse 190 8057 Zurich Switzerland.,Department of Biological and Environmental Sciences University of Gothenburg PO Box 463 40530 Gothenburg Sweden
| | - Ingrid Ahnesjö
- Department of Ecology and Genetics/Animal Ecology Uppsala University Norbyvägen 18D 75236 Uppsala Sweden
| | - Charlotta Kvarnemo
- Department of Biological and Environmental Sciences University of Gothenburg PO Box 463 40530 Gothenburg Sweden
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15
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An integrated modeling approach for atmospheric corrosion in presence of a varying electrolyte film. Electrochim Acta 2016. [DOI: 10.1016/j.electacta.2015.11.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Expression and functioning of retinal-based proton pumps in a saltern crystallizer brine. Extremophiles 2015; 20:69-77. [DOI: 10.1007/s00792-015-0798-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 10/15/2015] [Indexed: 10/22/2022]
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17
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Assessment of electrochemical properties of a biogalvanic system for tissue characterisation. Bioelectrochemistry 2014; 101:138-45. [PMID: 25460609 PMCID: PMC4247390 DOI: 10.1016/j.bioelechem.2014.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Revised: 10/13/2014] [Accepted: 10/15/2014] [Indexed: 12/02/2022]
Abstract
Biogalvanic characterisation is a promising method for obtaining health-specific tissue information. However, there is a dearth of understanding in the literature regarding the underlying galvanic cell, electrode reactions and their controlling factors which limits the application of the technique. This work presents a parametric electrochemical investigation into a zinc–copper galvanic system using salt (NaCl) solution analogues at physiologically-relevant concentrations (1.71, 17.1 & 154 mM). The potential difference at open cell, closed cell maximum current and the internal resistance (based on published characterisation methods) were measured. Additionally, independent and relative polarisation scans of the electrodes were performed to improve understanding of the system. Our findings suggest that the prominent reaction at the cathode is that of oxygen-reduction, not hydrogen-evolution. Results indicate that cell potentials are influenced by the concentration of dissolved oxygen at low currents and maximum closed cell currents are limited by the rate of oxygen diffusion to the cathode. Characterised internal resistance values for the salt solutions did not correspond to theoretical values at the extremes of concentration (1.71 and 154 mM) due to electrode resistance and current limitation. Existing biogalvanic models do not consider these phenomena and should be improved to advance the technique and its practical application. Electrochemical evaluation of the biogalvanic characterisation system in NaCl Influence of NaCl concentration on the system has been examined. Reaction at the cathode demonstrated to be oxygen-reduction not hydrogen-evolution Cell voltage dependent on the oxygen concentration of the system (tissue) Electrode resistance and diffusion limitation skew characterisation
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Bioenergetics of the moderately halophilic bacterium Halobacillus halophilus: composition and regulation of the respiratory chain. Appl Environ Microbiol 2013; 79:3839-46. [PMID: 23584768 DOI: 10.1128/aem.00855-13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In their natural environments, moderately halophilic bacteria are confronted not only with high salinities but also with low oxygen tensions due to the high salinities. The growth of H. halophilus is strictly aerobic. To analyze the dependence of respiration on the NaCl concentration and oxygen availability of the medium, resting cell experiments were performed. The respiration rates were dependent on the NaCl concentration of the growth medium, as well as on the NaCl concentration of the assay buffer, indicating regulation on the transcriptional and the activity level. Respiration was accompanied by the generation of an electrochemical proton potential (Δμ(H+)) across the cytoplasmic membrane whose magnitude was dependent on the external pH. Genes encoding proteins involved in respiration and Δμ(H+) generation, such as a noncoupled NADH dehydrogenase (NDH-2), complex II, and complex III, were identified in the genome. In addition, genes encoding five different terminal oxidases are present. Inhibitor profiling revealed the presence of NDH-2 and complex III, but the nature of the oxidases could not be resolved using this approach. Expression analysis demonstrated that all the different terminal oxidases were indeed expressed, but by far the most prominent was cta, encoding cytochrome caa3 oxidase. The expression of all of the different oxidase genes increased at high NaCl concentrations, and the transcript levels of cta and qox (encoding cytochrome aa3 oxidase) also increased at low oxygen concentrations. These data culminate in a model of the composition and variation of the respiratory chain of H. halophilus.
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Life at High Salt and Low Oxygen: How Do the Halobacteriaceae Cope with Low Oxygen Concentrations in Their Environment? CELLULAR ORIGIN, LIFE IN EXTREME HABITATS AND ASTROBIOLOGY 2013. [DOI: 10.1007/978-94-007-6488-0_24] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Oren A. The function of gas vesicles in halophilic archaea and bacteria: theories and experimental evidence. Life (Basel) 2012; 3:1-20. [PMID: 25371329 PMCID: PMC4187190 DOI: 10.3390/life3010001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 12/16/2012] [Accepted: 12/17/2012] [Indexed: 01/15/2023] Open
Abstract
A few extremely halophilic Archaea (Halobacterium salinarum, Haloquadratum walsbyi, Haloferax mediterranei, Halorubrum vacuolatum, Halogeometricum borinquense, Haloplanus spp.) possess gas vesicles that bestow buoyancy on the cells. Gas vesicles are also produced by the anaerobic endospore-forming halophilic Bacteria Sporohalobacter lortetii and Orenia sivashensis. We have extensive information on the properties of gas vesicles in Hbt. salinarum and Hfx. mediterranei and the regulation of their formation. Different functions were suggested for gas vesicle synthesis: buoying cells towards oxygen-rich surface layers in hypersaline water bodies to prevent oxygen limitation, reaching higher light intensities for the light-driven proton pump bacteriorhodopsin, positioning the cells optimally for light absorption, light shielding, reducing the cytoplasmic volume leading to a higher surface-area-to-volume ratio (for the Archaea) and dispersal of endospores (for the anaerobic spore-forming Bacteria). Except for Hqr. walsbyi which abounds in saltern crystallizer brines, gas-vacuolate halophiles are not among the dominant life forms in hypersaline environments. There only has been little research on gas vesicles in natural communities of halophilic microorganisms, and the few existing studies failed to provide clear evidence for their possible function. This paper summarizes the current status of the different theories why gas vesicles may provide a selective advantage to some halophilic microorganisms.
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Affiliation(s)
- Aharon Oren
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, 91904, Jerusalem, Israel.
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