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Helliwell KE, Kleiner FH, Hardstaff H, Chrachri A, Gaikwad T, Salmon D, Smirnoff N, Wheeler GL, Brownlee C. Spatiotemporal patterns of intracellular Ca 2+ signalling govern hypo-osmotic stress resilience in marine diatoms. THE NEW PHYTOLOGIST 2021; 230:155-170. [PMID: 33486789 DOI: 10.1111/nph.17162] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Accepted: 12/11/2020] [Indexed: 05/15/2023]
Abstract
Diatoms are globally important phytoplankton that dominate coastal and polar-ice assemblages. These environments exhibit substantial changes in salinity over dynamic spatiotemporal regimes. Rapid sensory systems are vital to mitigate the harmful consequences of osmotic stress. Population-based analyses have suggested that Ca2+ signalling is involved in diatom osmotic sensing. However, mechanistic insight of the role of osmotic Ca2+ signalling is limited. Here, we show that Phaeodactylum Ca2+ elevations are essential for surviving hypo-osmotic shock. Moreover, employing novel single-cell imaging techniques we have characterised real-time Ca2+ signalling responses in single diatom cells to environmental osmotic perturbations. We observe that intracellular spatiotemporal patterns of osmotic-induced Ca2+ elevations encode vital information regarding the nature of the osmotic stimulus. Localised Ca2+ signals evoked by mild or gradual hypo-osmotic shocks are propagated globally from the apical cell tips, enabling fine-tuned cell volume regulation across the whole cell. Finally, we demonstrate that diatoms adopt Ca2+ -independent and dependent mechanisms for osmoregulation. We find that efflux of organic osmolytes occurs in a Ca2+ -independent manner, but this response is insufficient to mitigate cell damage during hypo-osmotic shock. By comparison, Ca2+ -dependent signalling is necessary to prevent cell bursting via precise coordination of K+ transport, and therefore is likely to underpin survival in dynamic osmotic environments.
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Affiliation(s)
- Katherine E Helliwell
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Friedrich H Kleiner
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
- School of Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK
| | - Hayley Hardstaff
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
| | - Abdul Chrachri
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
| | - Trupti Gaikwad
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
| | - Deborah Salmon
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Nicholas Smirnoff
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Glen L Wheeler
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
| | - Colin Brownlee
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
- School of Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK
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Iglesias MJ, Soengas R, Probert I, Guilloud E, Gourvil P, Mehiri M, López Y, Cepas V, Gutiérrez-Del-Río I, Redondo-Blanco S, Villar CJ, Lombó F, Soto S, Ortiz FL. NMR characterization and evaluation of antibacterial and antiobiofilm activity of organic extracts from stationary phase batch cultures of five marine microalgae (Dunaliella sp., D. salina, Chaetoceros calcitrans, C. gracilis and Tisochrysis lutea). PHYTOCHEMISTRY 2019; 164:192-205. [PMID: 31174083 DOI: 10.1016/j.phytochem.2019.05.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 04/11/2019] [Accepted: 05/06/2019] [Indexed: 06/09/2023]
Abstract
The chemical composition of five marine microalgae (Dunaliella sp., Dunaliella salina, Chaetoceros calcitrans, Chaetoceros gracilis and Tisochrysis lutea) was investigated through nuclear magnetic resonance (NMR) spectroscopic study of the soluble material obtained by sequential extraction with hexane, ethyl acetate (AcOEt) and methanol of biomass from stationary phase cultures. Hexane extracted the major lipids present in the microalgae during the stationary phase of growth, which correspond to storage lipids. Triacylglycerols (TGs) were the only storage lipids produced by Dunaliella and Chaetoceros. In contrast, T. lutea predominantly stored polyunsaturated long-chain alkenones, with sterols also detected as minor components of the hexane extract. The molecular structure of brassicasterol was determined in T. lutea and the presence of squalene in this sample was also unequivocally detected. Monogalactosyldiacylglycerols (MGDGs) and pigments were concentrated in the AcOEt extracts. C. calcitrans and D. salina constituted an exception due to the high amount of TGs and glycerol produced, respectively, by these two strains. Chlorophylls a and b and β-carotene were the major pigments synthesized by Dunaliella and chlorophyll a and fucoxanthin were the only pigments detected in Chaetoceros and T. lutea. Information concerning the acyl chains present in TGs and MGDGs as well as the positional distribution of acyl chains on the glycerol moiety was obtained by NMR analysis of hexane and AcOEt extracts, with results consistent with those expected for the genera studied. Fatty acid composition of TGs in the two Dunaliella strains was different, with polyunsaturated acyl chains almost absent in the storage lipids produced by D. salina. Except in C. calcitrans, the polar nature of soluble compounds was inferred through the relative extraction yield using methanol as the extraction solvent. Glycerol was the major component of this fraction for the Dunaliella strains. In T. lutea 1,4/2,5-cyclohexanetetrol (CHT) and dimethylsulfoniopropionate (DMSP) preponderated. CHT was also the major polyol present in the Chaetoceros strains in which DMSP was not detected, but prominent signals of 2,3-dihydroxypropane-1-sulfonate (DHSP) were observed in the 1H NMR spectra of methanolic extracts. The presence of DHSP confirms the production of this metabolite by diatoms. In addition, several other minor compounds (digalactosyldiacyglycerols (DGDGs), sulphoquinovosyldiacylglycerols (SQDGs), amino acids, carbohydrates, scyllo-inositol, mannitol, lactic acid and homarine) were also identified in the methanolic extracts. The antibacterial and antibiofilm activities of the extracts were tested. The AcOEt extract from C. gracilis showed a moderate antibiofilm activity.
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Affiliation(s)
- Ma José Iglesias
- Área de Química Orgánica, Research Centre CIAIMBITAL, Universidad de Almería, Carretera de Sacramento s/n, Almería, 04120, Spain.
| | - Raquel Soengas
- Área de Química Orgánica, Research Centre CIAIMBITAL, Universidad de Almería, Carretera de Sacramento s/n, Almería, 04120, Spain
| | - Ian Probert
- Roscoff Culture Collection, FR2424 Station Biologique de Roscoff (Sorbonne Université / CNRS), 29680, Roscoff, France
| | - Emilie Guilloud
- Roscoff Culture Collection, FR2424 Station Biologique de Roscoff (Sorbonne Université / CNRS), 29680, Roscoff, France
| | - Priscillia Gourvil
- Roscoff Culture Collection, FR2424 Station Biologique de Roscoff (Sorbonne Université / CNRS), 29680, Roscoff, France
| | - Mohamed Mehiri
- Institut de Chimie de Nice, UMR CNRS 7272, Université Nice Sofia Antopolis, 06103, Nice, France
| | - Yuly López
- Barcelona Institute for Global Health (ISGlobal)-Hospital Clinic-Universitat de Barcelona, Carrer Rosselló 132, 08036, Barcelona, Spain
| | - Virginio Cepas
- Barcelona Institute for Global Health (ISGlobal)-Hospital Clinic-Universitat de Barcelona, Carrer Rosselló 132, 08036, Barcelona, Spain
| | - Ignacio Gutiérrez-Del-Río
- Research Group BIONUC, Departamento de Biología Funcional, Área de Microbiología, University of Oviedo, Oviedo, Principality of Asturias, Spain. IUOPA (Instituto Universitario de Oncología del Principado de Asturias), ISPA (Instituto de Investigación Sanitaria del Principado de Asturias), Spain
| | - Saúl Redondo-Blanco
- Research Group BIONUC, Departamento de Biología Funcional, Área de Microbiología, University of Oviedo, Oviedo, Principality of Asturias, Spain. IUOPA (Instituto Universitario de Oncología del Principado de Asturias), ISPA (Instituto de Investigación Sanitaria del Principado de Asturias), Spain
| | - Claudio J Villar
- Research Group BIONUC, Departamento de Biología Funcional, Área de Microbiología, University of Oviedo, Oviedo, Principality of Asturias, Spain. IUOPA (Instituto Universitario de Oncología del Principado de Asturias), ISPA (Instituto de Investigación Sanitaria del Principado de Asturias), Spain
| | - Felipe Lombó
- Research Group BIONUC, Departamento de Biología Funcional, Área de Microbiología, University of Oviedo, Oviedo, Principality of Asturias, Spain. IUOPA (Instituto Universitario de Oncología del Principado de Asturias), ISPA (Instituto de Investigación Sanitaria del Principado de Asturias), Spain
| | - Sara Soto
- Barcelona Institute for Global Health (ISGlobal)-Hospital Clinic-Universitat de Barcelona, Carrer Rosselló 132, 08036, Barcelona, Spain
| | - Fernando López Ortiz
- Área de Química Orgánica, Research Centre CIAIMBITAL, Universidad de Almería, Carretera de Sacramento s/n, Almería, 04120, Spain.
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Ayache N, Hervé F, Martin-Jézéquel V, Amzil Z, Caruana AMN. Influence of sudden salinity variation on the physiology and domoic acid production by two strains of Pseudo-nitzschia australis. JOURNAL OF PHYCOLOGY 2019; 55:186-195. [PMID: 30329158 DOI: 10.1111/jpy.12801] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 10/02/2018] [Indexed: 05/20/2023]
Abstract
Several coastal countries including France have experienced serious and increasing problems related to Pseudo-nitzschia toxic blooms. These toxic blooms occur in estuarine and coastal waters potentially subject to fluctuations in salinity. In this study, we document for the first time the viability, growth, photosynthetic efficiency, and toxin production of two strains of Pseudo-nitzschia australis grown under conditions with sudden salinity changes. Following salinity variation, the two strains survived over a restricted salinity range of 30-35, with favorable physiological responses, as the growth, effective quantum yield and toxin content were high compared to the other conditions. In addition, high cellular quotas of domoic acid (DA) were observed at a salinity of 40 for the strain IFR-PAU-16.1 in comparison with the other strain IFR-PAU-16.2 where the cell DA content was directly released into the medium. On the other hand, the osmotic stress imposed at lower salinities, 20 and 10, resulted in cell lysis and a sudden DA leakage in the medium. Intra-specific variability was observed in growth and toxin production, with the strain IFR-PAU-16.1 apparently able to withstand higher salinities than the strain IFR-PAU-16.2. On the whole, DA does not appear to act as an osmolyte in response to sudden salinity changes. Since most of the shellfish harvesting areas of bivalve molluscs in France are located in areas where the salinity generally varies between 30 and 35, Pseudo-nitzschia australis blooms might potentially impact public health and commercial shellfish resources in these places.
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Affiliation(s)
- Nour Ayache
- IFREMER, Phycotoxins Laboratory, rue de l'Ile d'Yeu, BP 21105, 44311, Nantes, France
| | - Fabienne Hervé
- IFREMER, Phycotoxins Laboratory, rue de l'Ile d'Yeu, BP 21105, 44311, Nantes, France
| | | | - Zouher Amzil
- IFREMER, Phycotoxins Laboratory, rue de l'Ile d'Yeu, BP 21105, 44311, Nantes, France
| | - Amandine M N Caruana
- IFREMER, Phycotoxins Laboratory, rue de l'Ile d'Yeu, BP 21105, 44311, Nantes, France
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Scholz B, Küpper FC, Vyverman W, Ólafsson HG, Karsten U. Chytridiomycosis of Marine Diatoms-The Role of Stress Physiology and Resistance in Parasite-Host Recognition and Accumulation of Defense Molecules. Mar Drugs 2017; 15:E26. [PMID: 28125065 PMCID: PMC5334607 DOI: 10.3390/md15020026] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 01/07/2017] [Accepted: 01/13/2017] [Indexed: 02/05/2023] Open
Abstract
Little is known about the role of chemotaxis in the location and attachment of chytrid zoospores to potential diatom hosts. Hypothesizing that environmental stress parameters affect parasite-host recognition, four chytrid-diatom tandem cultures (Chytridium sp./Navicula sp., Rhizophydium type I/Nitzschia sp., Rhizophydium type IIa/Rhizosolenia sp., Rhizophydium type IIb/Chaetoceros sp.) were used to test the chemotaxis of chytrid zoospores and the presence of potential defense molecules in a non-contact-co-culturing approach. As potential triggers in the chemotaxis experiments, standards of eight carbohydrates, six amino acids, five fatty acids, and three compounds known as compatible solutes were used in individual and mixed solutions, respectively. In all tested cases, the whole-cell extracts of the light-stressed (continuous light exposure combined with 6 h UV radiation) hosts attracted the highest numbers of zoospores (86%), followed by the combined carbohydrate standard solution (76%), while all other compounds acted as weak triggers only. The results of the phytochemical screening, using biomass and supernatant extracts of susceptible and resistant host-diatom cultures, indicated in most of the tested extracts the presence of polyunsaturated fatty acids, phenols, and aldehydes, whereas the bioactivity screenings showed that the zoospores of the chytrid parasites were only significantly affected by the ethanolic supernatant extract of the resistant hosts.
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Affiliation(s)
- Bettina Scholz
- BioPol ehf., Einbúastig 2, 545 Skagaströnd, Iceland.
- Faculty of Natural Resource Sciences, University of Akureyri, Borgir v. Nordurslod, IS 600 Akureyri, Iceland.
| | - Frithjof C Küpper
- Oceanlab, University of Aberdeen, Main Street, Newburgh AB41 6AA, Scotland, UK.
| | - Wim Vyverman
- Department of Biology, Section of Protistology and Aquatic Ecology, University of Ghent, Krijgslaan 281 S8, 9000 Ghent, Belgium.
| | | | - Ulf Karsten
- Institute of Biological Sciences, Applied Ecology & Phycology, University of Rostock, Albert-Einstein-Strasse 3, 18059 Rostock, Germany.
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Pal D, Khozin-Goldberg I, Didi-Cohen S, Solovchenko A, Batushansky A, Kaye Y, Sikron N, Samani T, Fait A, Boussiba S. Growth, lipid production and metabolic adjustments in the euryhaline eustigmatophyte Nannochloropsis oceanica CCALA 804 in response to osmotic downshift. Appl Microbiol Biotechnol 2013; 97:8291-306. [DOI: 10.1007/s00253-013-5092-6] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 06/27/2013] [Accepted: 07/01/2013] [Indexed: 12/24/2022]
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Gebser B, Pohnert G. Synchronized regulation of different zwitterionic metabolites in the osmoadaption of phytoplankton. Mar Drugs 2013; 11:2168-82. [PMID: 23774888 PMCID: PMC3721227 DOI: 10.3390/md11062168] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 04/23/2013] [Accepted: 05/28/2013] [Indexed: 11/16/2022] Open
Abstract
The ability to adapt to different seawater salinities is essential for cosmopolitan marine phytoplankton living in very diverse habitats. In this study, we examined the role of small zwitterionic metabolites in the osmoadaption of two common microalgae species Emiliania huxleyi and Prorocentrum minimum. By cultivation of the algae under salinities between 16‰ and 38‰ and subsequent analysis of dimethylsulfoniopropionate (DMSP), glycine betaine (GBT), gonyol, homarine, trigonelline, dimethylsulfonioacetate, trimethylammonium propionate, and trimethylammonium butyrate using HPLC-MS, we could reveal two fundamentally different osmoadaption mechanisms. While E. huxleyi responded with cell size reduction and a nearly constant ratio between the major metabolites DMSP, GBT and homarine to increasing salinity, osmolyte composition of P. minimum changed dramatically. In this alga DMSP concentration remained nearly constant at 18.6 mM between 20‰ and 32‰ but the amount of GBT and dimethylsulfonioacetate increased from 4% to 30% of total investigated osmolytes. Direct quantification of zwitterionic metabolites via LC-MS is a powerful tool to unravel the complex osmoadaption and regulation mechanisms of marine phytoplankton.
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Affiliation(s)
| | - Georg Pohnert
- Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University, Lessingstr. 8, D-07743 Jena, Germany; E-Mail:
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McKew BA, Taylor JD, McGenity TJ, Underwood GJC. Resistance and resilience of benthic biofilm communities from a temperate saltmarsh to desiccation and rewetting. ISME JOURNAL 2010; 5:30-41. [PMID: 20596071 DOI: 10.1038/ismej.2010.91] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Periods of desiccation and rewetting are regular, yet stressful events encountered by saltmarsh microbial communities. To examine the resistance and resilience of microbial biofilms to such stresses, sediments from saltmarsh creeks were allowed to desiccate for 23 days, followed by rewetting for 4 days, whereas control sediments were maintained under a natural tidal cycle. In the top 2 mm of the dry sediments, salinity increased steadily from 36 to 231 over 23 days, and returned to seawater salinity on rewetting. After 3 days, desiccated sediments had a lower chlorophyll a (Chl a) fluorescence signal as benthic diatoms ceased to migrate to the surface, with a recovery in cell migration and Chl a fluorescence on rewetting. Extracellular β-glucosidase and aminopeptidase activities decreased within the first week of drying, but increased sharply on rewetting. The bacterial community in the desiccating sediment changed significantly from the controls after 14 days of desiccation (salinity 144). Rewetting did not cause a return to the original community composition, but led to a further change. Pyrosequencing analysis of 16S rRNA genes amplified from the sediment revealed diverse microbial responses, for example desiccation enabled haloversatile Marinobacter species to increase their relative abundance, and thus take advantage of rewetting to grow rapidly and dominate the community. A temporal sequence of effects of desiccation and rewetting were thus observed, but the most notable feature was the overall resistance and resilience of the microbial community.
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Affiliation(s)
- Boyd A McKew
- Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, UK.
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