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Szczepocka E, Nowicka-Krawczyk P, Wolski GJ. Terrestrial mosses as a substrate and potential host for cyanobacteria, green algae and diatoms. JOURNAL OF PLANT RESEARCH 2024; 137:847-861. [PMID: 38935314 PMCID: PMC11392977 DOI: 10.1007/s10265-024-01551-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 05/29/2024] [Indexed: 06/28/2024]
Abstract
Most studies of terrestrial bryophytes as natural substrates for photosynthetic microorganisms have been performed in the polar regions, where bryophytes are an important part of the ecosystem. As they remain green throughout the year, bryophytes may also be an ideal substrate for epiphytic organisms in temperate regions. The present study investigated the colonization potential and diversity of microalgae on selected plant species in riparian forest and spruce monoculture in a temperate region. It examines whether the presence of algae is related to substrate humidity, the micromorphology of gametophyte or the seasonal availability of substrate. The taxonomic diversity of algae was studied. Cyanobacteria and green algae were cultured on BG-11 agar medium, while diatoms were identified in permanent diatomaceous slides. The alpha- and beta-diversity indices were calculated, and the communities were compared using Bray-Curtis distances and multidimensional correspondence analyses. Our findings indicate that the largest number of alga species were diatoms; however, their presence was only observed in riparian forest and was associated with high humidity. Both aerophilic and freshwater taxa were noted, the latter carried by water from nearby aquatic ecosystem. Green algae were present in both phytocoenoses and humidity appears to have no substantial effect on the degree of colonization; their diversity was low and the group consisted of terrestrial taxa. In two bryophytes growing at the highest humidity, cyanobacteria were only identified in culture. The key factor influencing the degree of microalgae colonization was the humidity of the substrate, which was related to the distance from water.
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Affiliation(s)
- Ewelina Szczepocka
- Department of Algology and Mycology, Faculty of Biology and Environmental Protection, University of Lodz, Banacha 12/16, Lodz, 90-237, Poland.
| | - Paulina Nowicka-Krawczyk
- Department of Algology and Mycology, Faculty of Biology and Environmental Protection, University of Lodz, Banacha 12/16, Lodz, 90-237, Poland
| | - Grzegorz J Wolski
- Department of Geobotany and Plant Ecology, Faculty of Biology and Environmental Protection, University of Lodz, Banacha 12/16, Lodz, 90-237, Poland
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2
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Arzac MI, Miranda-Apodaca J, de Los Ríos A, Castanyer-Mallol F, García-Plazaola JI, Fernández-Marín B. The outstanding capacity of Prasiola antarctica to thrive in contrasting harsh environments relies on the constitutive protection of thylakoids and on morphological plasticity. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 119:65-83. [PMID: 38608130 DOI: 10.1111/tpj.16742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 02/29/2024] [Accepted: 03/14/2024] [Indexed: 04/14/2024]
Abstract
The determination of physiological tolerance ranges of photosynthetic species and of the biochemical mechanisms underneath are fundamental to identify target processes and metabolites that will inspire enhanced plant management and production for the future. In this context, the terrestrial green algae within the genus Prasiola represent ideal models due to their success in harsh environments (polar tundras) and their extraordinary ecological plasticity. Here we focus on the outstanding Prasiola antarctica and compare two natural populations living in very contrasting microenvironments in Antarctica: the dry sandy substrate of a beach and the rocky bed of an ephemeral freshwater stream. Specifically, we assessed their photosynthetic performance at different temperatures, reporting for the first time gnsd values in algae and changes in thylakoid metabolites in response to extreme desiccation. Stream population showed lower α-tocopherol content and thicker cell walls and thus, lower gnsd and photosynthesis. Both populations had high temperatures for optimal photosynthesis (around +20°C) and strong constitutive tolerance to freezing and desiccation. This tolerance seems to be related to the high constitutive levels of xanthophylls and of the cylindrical lipids di- and tri-galactosyldiacylglycerol in thylakoids, very likely related to the effective protection and stability of membranes. Overall, P. antarctica shows a complex battery of constitutive and plastic protective mechanisms that enable it to thrive under harsh conditions and to acclimate to very contrasting microenvironments, respectively. Some of these anatomical and biochemical adaptations may partially limit photosynthesis, but this has a great potential to rise in a context of increasing temperature.
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Affiliation(s)
- Miren I Arzac
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940, Leioa, Spain
| | - Jon Miranda-Apodaca
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940, Leioa, Spain
| | - Asunción de Los Ríos
- Museo Nacional de Ciencias Naturales (MNCN-CSIC), Serrano 115 dpdo, 28006, Madrid, Spain
| | - Francesc Castanyer-Mallol
- Research Group on Plant Biology under Mediterranean Conditions, Department of Biology, Universitat de les Illes Balears (UIB), INAGEA, Balearic Islands, Palma, Spain
| | - José I García-Plazaola
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940, Leioa, Spain
| | - Beatriz Fernández-Marín
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940, Leioa, Spain
- Department of Botany, Ecology and Plant Physiology, University of La Laguna (ULL), Canary Islands, 38200, La Laguna, Spain
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Wang Y, Coyne KJ. Molecular Insights into the Synergistic Effects of Putrescine and Ammonium on Dinoflagellates. Int J Mol Sci 2024; 25:1306. [PMID: 38279308 PMCID: PMC10816187 DOI: 10.3390/ijms25021306] [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: 11/30/2023] [Revised: 01/13/2024] [Accepted: 01/15/2024] [Indexed: 01/28/2024] Open
Abstract
Ammonium and polyamines are essential nitrogen metabolites in all living organisms. Crosstalk between ammonium and polyamines through their metabolic pathways has been demonstrated in plants and animals, while no research has been directed to explore this relationship in algae or to investigate the underlying molecular mechanisms. Previous research demonstrated that high concentrations of ammonium and putrescine were among the active substances in bacteria-derived algicide targeting dinoflagellates, suggesting that the biochemical inter-connection and/or interaction of these nitrogen compounds play an essential role in controlling these ecologically important algal species. In this research, putrescine, ammonium, or a combination of putrescine and ammonium was added to cultures of three dinoflagellate species to explore their effects. The results demonstrated the dose-dependent and species-specific synergistic effects of putrescine and ammonium on these species. To further explore the molecular mechanisms behind the synergistic effects, transcriptome analysis was conducted on dinoflagellate Karlodinium veneficum treated with putrescine or ammonium vs. a combination of putrescine and ammonium. The results suggested that the synergistic effects of putrescine and ammonium disrupted polyamine homeostasis and reduced ammonium tolerance, which may have contributed to the cell death of K. veneficum. There was also transcriptomic evidence of damage to chloroplasts and impaired photosynthesis of K. veneficum. This research illustrates the molecular mechanisms underlying the synergistic effects of the major nitrogen metabolites, ammonium and putrescine, in dinoflagellates and provides direction for future studies on polyamine biology in algal species.
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Affiliation(s)
| | - Kathryn J. Coyne
- College of Earth, Ocean, and Environment, University of Delaware, Lewes, DE 19958, USA;
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Huang G, Wu Y, Gan H, Chu L. Overexpression of CD2/CD27 could inhibit the activation of nitrogen metabolism pathways and suppress M2 polarization of macrophages, thereby preventing brain metastasis of breast cancer. Transl Oncol 2023; 37:101768. [PMID: 37666207 PMCID: PMC10480780 DOI: 10.1016/j.tranon.2023.101768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 08/09/2023] [Accepted: 08/18/2023] [Indexed: 09/06/2023] Open
Abstract
OBJECTIVE Our study aimed to reveal the possible molecular mechanisms of CD2 and CD27 in influencing the tumor microenvironment of breast cancer (BC) brain metastasis based on the TCGA (The Cancer Genome Atlas) and SRA (Sequence Read Archive) databases. METHODS We calculated the proportions of tumor-infiltrating immune cells and the immune and stromal cell scores in 1222 BC samples from the TCGA-BRCA dataset, followed by identification of candidate DEGs. We further screened for BC brain metastasis-related DEGs in the BC brain metastasis dataset SUB12911144 from the SRA database. Finally, we established a mouse breast cancer brain metastasis model for in vivo validation. RESULTS We further screened two immune-regulatory DEGs (CD2 and CD27). GSEA analysis showed that the downregulation of CD2 and CD27 expression was closely related to the activation of nitrogen metabolism pathways. CIBERSORT algorithm analysis showed a correlation between the expression of 16 types of tumor-infiltrating immune cells and CD2 and 19 types of tumor-infiltrating immune cells and CD27. In addition, CD2 and CD27 expression were negatively associated with the proportion of M2 macrophages. In vivo experimental results demonstrated that overexpression of CD2/CD27 could suppress the M2 polarization of macrophages and inhibit breast cancer brain metastasis. CONCLUSION In the tumor microenvironment, overexpression of CD2/CD27 inhibited the activation of nitrogen metabolism pathways and suppressed M2 polarization of macrophages, thereby preventing brain metastasis of breast cancer.
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Affiliation(s)
- Guanyou Huang
- Department of Neurosurgery, The Second People's Hospital of Guiyang (Jinyang Hospital), No.547 Jinyang South Road, Guanshanhu District, Guiyang 550081, China.
| | - Yujuan Wu
- Department of Neurology, The Second People's Hospital of Guiyang (Jinyang Hospital), No.547 Jinyang South Road, Guanshanhu District, Guiyang 550081, China
| | - Hongchuan Gan
- Department of Neurosurgery, The Second People's Hospital of Guiyang (Jinyang Hospital), No.547 Jinyang South Road, Guanshanhu District, Guiyang 550081, China
| | - Liangzhao Chu
- Department of Neurosurgery, The Affiliated Hospital of Guizhou Medical University, Guiyang 550001, China
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Holzinger A, Plag N, Karsten U, Glaser K. Terrestrial Trentepohlia sp. (Ulvophyceae) from alpine and coastal collection sites show strong desiccation tolerance and broad light and temperature adaptation. PROTOPLASMA 2023; 260:1539-1553. [PMID: 37291393 PMCID: PMC10590310 DOI: 10.1007/s00709-023-01866-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 05/20/2023] [Indexed: 06/10/2023]
Abstract
For the present study, we collected the Ulvophyceae species Trentepohlia aurea from limestone rock near Berchtesgaden, Germany, and the closely related taxa T. umbrina from Tilia cordata tree bark and T. jolithus from concrete wall both in Rostock, Germany. Freshly sampled material stained with Auramine O, DIOC6, and FM 1-43 showed an intact physiological status. Cell walls were depicted with calcofluor white and Carbotrace. When subjected to three repeated and controlled cycles of desiccation over silica gel (~ 10% relative humidity) followed by rehydration, T. aurea recovered about 50% of the initial photosynthetic yield of photosystem II (YII). In contrast, T. umbrina and T. jolithus recovered to 100% of the initial YII. HPLC and GC analysis of compatible solutes found highest proportions of erythritol in T. umbrina and mannitol/arabitol in T. jolithus. The lowest total compatible solute concentrations were detected in T. aurea, while the C/N ratio was highest in this species, indicative of nitrogen limitation. The prominent orange to red coloration of all Trentepohlia was due to extremely high carotenoid to Chl a ratio (15.9 in T. jolithus, 7.8 in T. aurea, and 6.6. in T. umbrina). Photosynthetic oxygen production was positive up to ~ 1500 µmol photons m-2 s-1 with the highest Pmax and alpha values in T. aurea. All strains showed a broad temperature tolerance with optima for gross photosynthesis between 20 and 35 °C. The presented data suggest that all investigated Trentepohlia species are well adapted to their terrestrial lifestyle on exposed to sunlight on a vertical substrate with little water holding capacity. Nevertheless, the three Trentepohlia species differed concerning their desiccation tolerance and compatible solute concentrations. The lower compatible solute contents in T. aurea explain the incomplete recovery of YII after rehydration.
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Affiliation(s)
- Andreas Holzinger
- Department of Botany, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria.
| | - Niklas Plag
- Applied Phycology and Ecology, University of Rostock, Albert Einstein Strasse 3, 18059, Rostock, Germany
| | - Ulf Karsten
- Applied Phycology and Ecology, University of Rostock, Albert Einstein Strasse 3, 18059, Rostock, Germany
| | - Karin Glaser
- Applied Phycology and Ecology, University of Rostock, Albert Einstein Strasse 3, 18059, Rostock, Germany
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Fanesi A, Martin T, Breton C, Bernard O, Briandet R, Lopes F. The architecture and metabolic traits of monospecific photosynthetic biofilms studied in a custom flow-through system. Biotechnol Bioeng 2022; 119:2459-2470. [PMID: 35643824 DOI: 10.1002/bit.28147] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 04/28/2022] [Accepted: 05/19/2022] [Indexed: 11/07/2022]
Abstract
Microalgae biofilms have great ecological importance and high biotechnological potential. Nevertheless, an in-depth and combined structural (i.e., the architecture of the biofilm) and physiological characterization of microalgae biofilms is still missing. An approach able to provide the same time physiological and structural information during biofilm growth would be of paramount importance to understand these complex biological systems and to optimize their productivity. In this study, monospecific biofilms of a diatom and a green alga were grown under dynamic conditions in custom flow cells represented by UV/Vis spectroscopic cuvettes. Such flow cells were conceived to characterize the biofilms by several techniques mostly in situ and in a nondestructive way. Physiological traits were obtained by measuring variable chlorophyll a fluorescence by pulse amplitude modulated fluorometry and by scanning the biofilms in a spectrometer to obtain in vivo pigments spectral signatures. The architectural features were obtained by imaging the biofilms with a confocal laser scanning microscopy and an optical coherence tomography. Overall, this experimental setup allowed us to follow the growth of two biofilm-forming microalgae showing that cell physiology is more affected in complex biofilms likely as a consequence of alterations in local environmental conditions.
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Affiliation(s)
- Andrea Fanesi
- Laboratoire Génie des Procédés et Matériaux (LGPM), CentraleSupélec, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Thierry Martin
- Laboratoire Génie des Procédés et Matériaux (LGPM), CentraleSupélec, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Cyril Breton
- Laboratoire Génie des Procédés et Matériaux (LGPM), CentraleSupélec, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Olivier Bernard
- Biocore, INRIA, Université Côte d'Azur, Sophia Antipolis Cedex, France
| | - Romain Briandet
- Micalis Institute, AgroParisTech, INRAE, Université Paris-Saclay, Jouy-en-Josas, France
| | - Filipa Lopes
- Laboratoire Génie des Procédés et Matériaux (LGPM), CentraleSupélec, Université Paris-Saclay, Gif-sur-Yvette, France
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7
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Acquisition of desiccation tolerance in Haematococcus pluvialis requires photosynthesis and coincides with lipid and astaxanthin accumulation. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102699] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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8
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Metabolite Profiling in Green Microalgae with Varying Degrees of Desiccation Tolerance. Microorganisms 2022; 10:microorganisms10050946. [PMID: 35630392 PMCID: PMC9144557 DOI: 10.3390/microorganisms10050946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/27/2022] [Accepted: 04/29/2022] [Indexed: 11/17/2022] Open
Abstract
Trebouxiophyceae are microalgae occupying even extreme environments such as polar regions or deserts, terrestrial or aquatic, and can occur free-living or as lichen photobionts. Yet, it is poorly understood how environmental factors shape their metabolism. Here, we report on responses to light and temperature, and metabolic adjustments to desiccation in Diplosphaera epiphytica, isolated from a lichen, and Edaphochlorella mirabilis, isolated from Tundra soil, assessed via growth and photosynthetic performance parameters. Metabolite profiling was conducted by GC–MS. A meta-analysis together with data from a terrestrial and an aquatic Chlorella vulgaris strain reflected elements of phylogenetic relationship, lifestyle, and relative desiccation tolerance of the four algal strains. For example, compatible solutes associated with desiccation tolerance were up-accumulated in D. epiphytica, but also sugars and sugar alcohols typically produced by lichen photobionts. The aquatic C. vulgaris, the most desiccation-sensitive strain, showed the greatest variation in metabolite accumulation after desiccation and rehydration, whereas the most desiccation-tolerant strain, D. epiphytica, showed the least, suggesting that it has a more efficient constitutive protection from desiccation and/or that desiccation disturbed the metabolic steady-state less than in the other three strains. The authors hope that this study will stimulate more research into desiccation tolerance mechanisms in these under-investigated microorganisms.
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Blázquez M, Hernández-Moreno LS, Gasulla F, Pérez-Vargas I, Pérez-Ortega S. The Role of Photobionts as Drivers of Diversification in an Island Radiation of Lichen-Forming Fungi. Front Microbiol 2022; 12:784182. [PMID: 35046912 PMCID: PMC8763358 DOI: 10.3389/fmicb.2021.784182] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/02/2021] [Indexed: 01/04/2023] Open
Abstract
Speciation in oceanic islands has attracted the interest of scientists since the 19th century. One of the most striking evolutionary phenomena that can be studied in islands is adaptive radiation, that is, when a lineage gives rise to different species by means of ecological speciation. Some of the best-known examples of adaptive radiation are charismatic organisms like the Darwin finches of the Galapagos and the cichlid fishes of the great African lakes. In these and many other examples, a segregation of the trophic niche has been shown to be an important diversification driver. Radiations are known in other groups of organisms, such as lichen-forming fungi. However, very few studies have investigated their adaptive nature, and none have focused on the trophic niche. In this study, we explore the role of the trophic niche in a putative radiation of endemic species from the Macaronesian Region, the Ramalina decipiens group. The photobiont diversity was studied by Illumina MiSeq sequencing of the ITS2 region of 197 specimens spanning the phylogenetic breadth and geographic range of the group. A total of 66 amplicon sequence variants belonging to the four main clades of the algal genus Trebouxia were found. Approximately half of the examined thalli showed algal coexistence, but in most of them, a single main photobiont amounted to more than 90% of the reads. However, there were no significant differences in photobiont identity and in the abundance of ITS2 reads across the species of the group. We conclude that a segregation of the trophic niche has not occurred in the R. decipiens radiation.
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Affiliation(s)
- Miguel Blázquez
- Department of Mycology, Real Jardín Botánico (CSIC), Madrid, Spain.,Open Access Publication Support Program, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.,Escuela Internacional de Doctorado, Universidad Rey Juan Carlos, Móstoles, Spain
| | - Lucía S Hernández-Moreno
- Department of Mycology, Real Jardín Botánico (CSIC), Madrid, Spain.,Open Access Publication Support Program, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Francisco Gasulla
- Department of Life Sciences, Universidad de Alcalá, Alcalá de Henares, Spain
| | - Israel Pérez-Vargas
- Department of Botany, Ecology and Plant Physiology, Universidad de La Laguna, San Cristóbal de La Laguna, Spain
| | - Sergio Pérez-Ortega
- Department of Mycology, Real Jardín Botánico (CSIC), Madrid, Spain.,Open Access Publication Support Program, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
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Cycil LM, Hausrath EM, Ming DW, Adcock CT, Raymond J, Remias D, Ruemmele WP. Investigating the Growth of Algae Under Low Atmospheric Pressures for Potential Food and Oxygen Production on Mars. Front Microbiol 2021; 12:733244. [PMID: 34867849 PMCID: PMC8633435 DOI: 10.3389/fmicb.2021.733244] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/28/2021] [Indexed: 11/13/2022] Open
Abstract
With long-term missions to Mars and beyond that would not allow resupply, a self-sustaining Bioregenerative Life Support System (BLSS) is essential. Algae are promising candidates for BLSS due to their completely edible biomass, fast growth rates and ease of handling. Extremophilic algae such as snow algae and halophilic algae may also be especially suited for a BLSS because of their ability to grow under extreme conditions. However, as indicated from over 50 prior space studies examining algal growth, little is known about the growth of algae at close to Mars-relevant pressures. Here, we explored the potential for five algae species to produce oxygen and food under low-pressure conditions relevant to Mars. These included Chloromonas brevispina, Kremastochrysopsis austriaca, Dunaliella salina, Chlorella vulgaris, and Spirulina plantensis. The cultures were grown in duplicate in a low-pressure growth chamber at 670 ± 20 mbar, 330 ± 20 mbar, 160 ± 20 mbar, and 80 ± 2.5 mbar pressures under continuous light exposure (62-70 μmol m-2 s-1). The atmosphere was evacuated and purged with CO2 after sampling each week. Growth experiments showed that D. salina, C. brevispina, and C. vulgaris were the best candidates to be used for BLSS at low pressure. The highest carrying capacities for each species under low pressure conditions were achieved by D. salina at 160 mbar (30.0 ± 4.6 × 105 cells/ml), followed by C. brevispina at 330 mbar (19.8 ± 0.9 × 105 cells/ml) and C. vulgaris at 160 mbar (13.0 ± 1.5 × 105 cells/ml). C. brevispina, D. salina, and C. vulgaris all also displayed substantial growth at the lowest tested pressure of 80 mbar reaching concentrations of 43.4 ± 2.5 × 104, 15.8 ± 1.3 × 104, and 57.1 ± 4.5 × 104 cells per ml, respectively. These results indicate that these species are promising candidates for the development of a Mars-based BLSS using low pressure (∼200-300 mbar) greenhouses and inflatable structures that have already been conceptualized and designed.
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Affiliation(s)
- Leena M Cycil
- Department of Geoscience, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Elisabeth M Hausrath
- Department of Geoscience, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | | | - Christopher T Adcock
- Department of Geoscience, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - James Raymond
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Daniel Remias
- School of Engineering, University of Applied Sciences Upper Austria, Wels, Austria
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Medwed C, Holzinger A, Hofer S, Hartmann A, Michalik D, Glaser K, Karsten U. Ecophysiological, morphological, and biochemical traits of free-living Diplosphaera chodatii (Trebouxiophyceae) reveal adaptation to harsh environmental conditions. PROTOPLASMA 2021; 258:1187-1199. [PMID: 33550447 PMCID: PMC8523416 DOI: 10.1007/s00709-021-01620-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 01/28/2021] [Indexed: 05/14/2023]
Abstract
Single-celled green algae within the Trebouxiophyceae (Chlorophyta) are typical components of terrestrial habitats, which often exhibit harsh environmental conditions for these microorganisms. This study provides a detailed overview of the ecophysiological, biochemical, and ultrastructural traits of an alga living on tree bark. The alga was isolated from a cypress tree in the Botanical Garden of Innsbruck (Austria) and identified by morphology and molecular phylogeny as Diplosphaera chodatii. Transmission electron microscopy after high-pressure freezing (HPF) showed an excellent preservation of the ultrastructure. The cell wall was bilayered with a smooth inner layer and an outer layer of polysaccharides with a fuzzy hair-like appearance that could possibly act as cell-cell adhesion mechanism and hence as a structural precursor supporting biofilm formation together with the mucilage observed occasionally. The photosynthetic-irradiance curves of D. chodatii indicated low light requirements without photoinhibition at high photon flux densities (1580 μmol photons m-2 s-1) supported by growth rate measurements. D. chodatii showed a high desiccation tolerance, as 85% of its initial value was recovered after controlled desiccation at a relative humidity of ~10%. The alga contained the low molecular weight carbohydrates sucrose and sorbitol, which probably act as protective compounds against desiccation. In addition, a new but chemically not elucidated mycosporine-like amino acid was detected with a molecular mass of 332 g mol-1 and an absorption maximum of 324 nm. The presented data provide various traits which contribute to a better understanding of the adaptive mechanisms of D. chodatii to terrestrial habitats.
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Affiliation(s)
- Cynthia Medwed
- Institute of Biological Science, Applied Ecology & Phycology, University of Rostock, Albert-Einstein-Strasse 3, D-18059, Rostock, Germany
| | - Andreas Holzinger
- Department of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, A-6020, Innsbruck, Austria
| | - Stefanie Hofer
- Department of Pharmacognosy, University of Innsbruck, Innrain 80-82, A-6020, Innsbruck, Austria
| | - Anja Hartmann
- Department of Pharmacognosy, University of Innsbruck, Innrain 80-82, A-6020, Innsbruck, Austria
| | - Dirk Michalik
- Institute of Chemistry, University of Rostock, Albert-Einstein-Strasse 3a, D-18059, Rostock, Germany
- Leibniz Institute of Catalysis, Albert-Einstein-Strasse 29a, D-18059, Rostock, Germany
| | - Karin Glaser
- Institute of Biological Science, Applied Ecology & Phycology, University of Rostock, Albert-Einstein-Strasse 3, D-18059, Rostock, Germany
| | - Ulf Karsten
- Institute of Biological Science, Applied Ecology & Phycology, University of Rostock, Albert-Einstein-Strasse 3, D-18059, Rostock, Germany.
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12
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Terlova EF, Holzinger A, Lewis LA. Terrestrial Green Algae Show Higher Tolerance to Dehydration than Do Their Aquatic Sister-Species. MICROBIAL ECOLOGY 2021; 82:770-782. [PMID: 33502573 PMCID: PMC7612456 DOI: 10.1007/s00248-020-01679-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 12/29/2020] [Indexed: 05/09/2023]
Abstract
Diverse algae possess the ability to recover from extreme desiccation without forming specialized resting structures. Green algal genera such as Tetradesmus (Sphaeropleales, Chlorophyceae) contain temperate terrestrial, desert, and aquatic species, providing an opportunity to compare physiological traits associated with the transition to land in closely related taxa. We subjected six species from distinct habitats to three dehydration treatments varying in relative humidity (RH 5%, 65%, 80%) followed by short- and long-term rehydration. We tested the capacity of the algae to recover from dehydration using the effective quantum yield of photosystem II as a proxy for physiological activity. The degree of recovery was dependent both on the habitat of origin and the dehydration scenario, with terrestrial, but not aquatic, species recovering from dehydration. Distinct strains of each species responded similarly to dehydration and rehydration, with the exception of one aquatic strain that recovered from the mildest dehydration treatment. Cell ultrastructure was uniformly maintained in both aquatic and desert species during dehydration and rehydration, but staining with an amphiphilic styryl dye indicated damage to the plasma membrane from osmotically induced water loss in the aquatic species. These analyses demonstrate that terrestrial Tetradesmus possess a vegetative desiccation tolerance phenotype, making these species ideal for comparative omics studies.
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Affiliation(s)
- Elizaveta F Terlova
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, 06269, USA.
| | - Andreas Holzinger
- Department of Botany, Functional Plant Biology, University of Innsbruck, Innsbruck, Austria
| | - Louise A Lewis
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, 06269, USA
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