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Wood C, Bruinink A, Trembath-Reichert E, Wilhelm MB, Vidal C, Balaban E, McKay CP, Swan R, Swan B, Goordial J. Active microbiota persist in dry permafrost and active layer from Elephant Head, Antarctica. ISME COMMUNICATIONS 2024; 4:ycad002. [PMID: 38304082 PMCID: PMC10833075 DOI: 10.1093/ismeco/ycad002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 10/03/2023] [Accepted: 11/07/2023] [Indexed: 02/03/2024]
Abstract
Dry permafrost is a challenging environment for microbial life due to cold, dry, and often oligotrophic conditions. In 2016, Elephant Head, Antarctica, was confirmed as the second site on Earth to contain dry permafrost. It is geographically distinct from the McMurdo Dry Valleys where dry permafrost has been studied previously. Here, we present the first study of the microbial activity, diversity, and functional potential of Elephant Head dry permafrost. Microbial activity was measured using radiorespiration assays with radiolabeled acetate as a carbon source at 5, 0, and -5°C. Low, but detectable, rates of microbial activity were measured in some samples at 0 and -5°C. This is distinct from previous studies of McMurdo Dry Valley dry permafrost which concluded that dry permafrost represents a cold-arid limit to life on the planet. The isolation of cold-adapted organisms from these soils, including one capable of subzero growth, further supports that the Elephant Head dry active layer and dry permafrost harbor viable microbial life, which may be active in situ. Metagenomic, 16S rRNA gene, and internal transcribed spacer and amplicon sequencing identified similar microbial communities to other Antarctic and cold environments. The Elephant Head microbial community appears to be adapted for survival in cold, dry, and oligotrophic conditions based on the presence of cold adaptation and stress response genes in the metagenomes. Together, our results show that dry permafrost environments do not exclude active microbial life at subzero temperatures, suggesting that the cold, dry soils of Mars may also not be as inhospitable as previously thought.
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Affiliation(s)
- Claudia Wood
- School of Environmental Sciences, University of Guelph, 50 Stone Rd E, Guelph, Ontario N1G 2W1, Canada
| | - Alyssa Bruinink
- School of Environmental Sciences, University of Guelph, 50 Stone Rd E, Guelph, Ontario N1G 2W1, Canada
| | - Elizabeth Trembath-Reichert
- School of Earth and Space Exploration, Arizona State University, 781 Terrace Mall, Tempe, AZ 85287, United States
| | - Mary Beth Wilhelm
- Space Science & Astrobiology Division, NASA Ames Research Center, Moffett Field, CA 94035, United States
| | - Chanel Vidal
- School of Earth and Space Exploration, Arizona State University, 781 Terrace Mall, Tempe, AZ 85287, United States
| | - Edward Balaban
- Space Science & Astrobiology Division, NASA Ames Research Center, Moffett Field, CA 94035, United States
| | - Christopher P McKay
- Space Science & Astrobiology Division, NASA Ames Research Center, Moffett Field, CA 94035, United States
| | - Robert Swan
- 2041 Foundation, 130 Wescott Ct, Auburn, CA 95603, United States
| | - Barney Swan
- 2041 Foundation, 130 Wescott Ct, Auburn, CA 95603, United States
| | - Jackie Goordial
- School of Environmental Sciences, University of Guelph, 50 Stone Rd E, Guelph, Ontario N1G 2W1, Canada
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Ramasamy KP, Mahawar L, Rajasabapathy R, Rajeshwari K, Miceli C, Pucciarelli S. Comprehensive insights on environmental adaptation strategies in Antarctic bacteria and biotechnological applications of cold adapted molecules. Front Microbiol 2023; 14:1197797. [PMID: 37396361 PMCID: PMC10312091 DOI: 10.3389/fmicb.2023.1197797] [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: 03/31/2023] [Accepted: 05/31/2023] [Indexed: 07/04/2023] Open
Abstract
Climate change and the induced environmental disturbances is one of the major threats that have a strong impact on bacterial communities in the Antarctic environment. To cope with the persistent extreme environment and inhospitable conditions, psychrophilic bacteria are thriving and displaying striking adaptive characteristics towards severe external factors including freezing temperature, sea ice, high radiation and salinity which indicates their potential in regulating climate change's environmental impacts. The review illustrates the different adaptation strategies of Antarctic microbes to changing climate factors at the structural, physiological and molecular level. Moreover, we discuss the recent developments in "omics" approaches to reveal polar "blackbox" of psychrophiles in order to gain a comprehensive picture of bacterial communities. The psychrophilic bacteria synthesize distinctive cold-adapted enzymes and molecules that have many more industrial applications than mesophilic ones in biotechnological industries. Hence, the review also emphasizes on the biotechnological potential of psychrophilic enzymes in different sectors and suggests the machine learning approach to study cold-adapted bacteria and engineering the industrially important enzymes for sustainable bioeconomy.
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Affiliation(s)
| | - Lovely Mahawar
- Department of Plant Physiology, Faculty of Agrobiology and Food Resources, Slovak University of Agriculture, Nitra, Slovakia
| | - Raju Rajasabapathy
- Department of Marine Science, Bharathidasan University, Tiruchirappalli, Tamilnadu, India
| | | | - Cristina Miceli
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Sandra Pucciarelli
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
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Cagide C, Marizcurrena JJ, Vallés D, Alvarez B, Castro-Sowinski S. A bacterial cold-active dye-decolorizing peroxidase from an Antarctic Pseudomonas strain. Appl Microbiol Biotechnol 2023; 107:1707-1724. [PMID: 36773063 DOI: 10.1007/s00253-023-12405-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 01/13/2023] [Accepted: 01/20/2023] [Indexed: 02/12/2023]
Abstract
DyP (dye-decolorizing peroxidase) enzymes are hemeproteins that catalyze the H2O2-dependent oxidation of various molecules and also carry out lignin degradation, albeit with low activity. We identified a dyp gene in the genome of an Antarctic cold-tolerant microbe (Pseudomonas sp. AU10) that codes for a class B DyP. The recombinant protein (rDyP-AU10) was produced using Escherichia coli as a host and purified. We found that rDyP-AU10 is mainly produced as a dimer and has characteristics that resemble psychrophilic enzymes, such as high activity at low temperatures (20 °C) when using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and H2O2 as substrates, thermo-instability, low content of arginine, and a catalytic pocket surface larger than the DyPs from some mesophilic and thermophilic microbes. We also report the steady-state kinetic parameters of rDyP-AU10 for ABTS, hydroquinone, and ascorbate. Stopped-flow kinetics revealed that Compound I is formed with a rate constant of (2.07 ± 0.09) × 106 M-1 s-1 at pH 5 and that this is the predominant species during turnover. The enzyme decolors dyes and modifies kraft lignin, suggesting that this enzyme may have potential use in bioremediation and in the cellulose and biofuel industries. KEY POINTS: • An Antarctic Pseudomonas strain produces a dye-decolorizing peroxidase. • The recombinant enzyme (rDyP-AU10) was produced in E. coli and purified. • rDyP-AU10 showed high activity at low temperatures. • rDyP-AU10 is potentially useful for biotechnological applications.
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Affiliation(s)
- Célica Cagide
- Sección Bioquímica, Instituto de Biología, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay
| | - Juan José Marizcurrena
- Sección Bioquímica, Instituto de Biología, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay
| | - Diego Vallés
- Laboratorio de Biocatalizadores y sus Aplicaciones, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay
| | - Beatriz Alvarez
- Laboratorio de Enzimología, Instituto de Química Biológica, Facultad de Ciencias, and Centro de Investigaciones Biomédicas, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay
| | - Susana Castro-Sowinski
- Sección Bioquímica, Instituto de Biología, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay.
- Laboratorio de Biocatalizadores y sus Aplicaciones, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay.
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Pittino F, Ambrosini R, Seeger M, Azzoni RS, Diolaiuti G, Alviz Gazitua P, Franzetti A. Geographical variability of bacterial communities of cryoconite holes of Andean glaciers. Sci Rep 2023; 13:2633. [PMID: 36788266 PMCID: PMC9929092 DOI: 10.1038/s41598-022-24373-5] [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: 04/20/2022] [Accepted: 11/14/2022] [Indexed: 02/16/2023] Open
Abstract
Cryoconite holes, ponds full of melting water with sediment on the bottom, are hotspots of biodiversity on glacier surfaces and host dynamic micro-ecosystems. They have been extensively investigated in different areas of the world (e.g., the Arctic, Antarctic, Alps, and Himalaya), but so far no study has described the bacterial communities of the glaciers in the Andes, the world's longest mountain range. In this study, we describe the bacterial communities of three small (< 2 km2) high-elevation (< 4200 m a.s.l.) glaciers of the Central Andes (Iver, East Iver and Morado glaciers) and two large (> 85 km2) glaciers of the Patagonian Andes (Exploradores and Perito Moreno glaciers) whose ablation tongues reach low altitude (< 300 m a.s.l.). Results show that the bacterial communities were generally similar to those observed in the cryoconite holes of other continents, but with few cyanobacteria (0.5% of sequences). The most abundant orders were Betaproteobacteriales, Cytophagales, Chitinophagales, Acetobacterales, Frankiales, Armatimonadales, Sphingobacteriales, Rhizobiales, Bacteroidales, Sphingomonadales, and Micrococcales. The bacterial communities differed between glaciers and both water pH and O2 concentration appeared to influence the bacterial community composition. This work thus provides the first description of the bacterial communities in cryoconite holes of South American glaciers.
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Affiliation(s)
- F. Pittino
- grid.7563.70000 0001 2174 1754Department of Earth and Environmental Sciences (DISAT), Università degli Studi di Milano-Bicocca, Milan, Italy ,grid.419754.a0000 0001 2259 5533WSL Swiss Federal Research Institute, Birmensdorf, Switzerland
| | - R. Ambrosini
- grid.4708.b0000 0004 1757 2822Laboratory of Glacier Ecology, Department of Environmental Science and Policy, Università degli Studi di Milano, Milan, Italy
| | - M. Seeger
- grid.12148.3e0000 0001 1958 645XMolecular Microbiology and Environmental Biotechnology Laboratory, Department of Chemistry, Universidad Técnica Federico Santa María, Valparaiso, Chile
| | - R. S. Azzoni
- grid.4708.b0000 0004 1757 2822Laboratory of Glacier Ecology, Department of Environmental Science and Policy, Università degli Studi di Milano, Milan, Italy ,grid.4708.b0000 0004 1757 2822Department of Earth Science “Ardito Desio”, Università degli Studi di Milano, Milan, Italy
| | - G. Diolaiuti
- grid.4708.b0000 0004 1757 2822Laboratory of Glacier Ecology, Department of Environmental Science and Policy, Università degli Studi di Milano, Milan, Italy
| | - P. Alviz Gazitua
- grid.442234.70000 0001 2295 9069Departamento de Ciencias Biológicas, Universidad de los Lagos, Osorno, Chile
| | - A. Franzetti
- grid.7563.70000 0001 2174 1754Department of Earth and Environmental Sciences (DISAT), Università degli Studi di Milano-Bicocca, Milan, Italy
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Pelosi B. Developing a bioinformatics pipeline for comparative protein classification analysis. BMC Genom Data 2022; 23:43. [PMID: 35668373 PMCID: PMC9172112 DOI: 10.1186/s12863-022-01045-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 03/11/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Protein classification is a task of paramount importance in various fields of biology. Despite the great momentum of modern implementation of protein classification, machine learning techniques such as Random Forest and Neural Network could not always be used for several reasons: data collection, unbalanced classification or labelling of the data.As an alternative, I propose the use of a bioinformatics pipeline to search for and classify information from protein databases. Hence, to evaluate the efficiency and accuracy of the pipeline, I focused on the carotenoid biosynthetic genes and developed a filtering approach to retrieve orthologs clusters in two well-studied plants that belong to the Brassicaceae family: Arabidopsis thaliana and Brassica rapa Pekinensis group. The result obtained has been compared with previous studies on carotenoid biosynthetic genes in B. rapa where phylogenetic analysis was conducted. RESULTS The developed bioinformatics pipeline relies on commercial software and multiple databeses including the use of phylogeny, Gene Ontology terms (GOs) and Protein Families (Pfams) at a protein level. Furthermore, the phylogeny is coupled with "population analysis" to evaluate the potential orthologs. All the steps taken together give a final table of potential orthologs. The phylogenetic tree gives a result of 43 putative orthologs conserved in B. rapa Pekinensis group. Different A. thaliana proteins have more than one syntenic ortholog as also shown in a previous finding (Li et al., BMC Genomics 16(1):1-11, 2015). CONCLUSIONS This study demonstrates that, when the biological features of proteins of interest are not specific, I can rely on a computational approach in filtering steps for classification purposes. The comparison of the results obtained here for the carotenoid biosynthetic genes with previous research confirmed the accuracy of the developed pipeline which can therefore be applied for filtering different types of datasets.
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Affiliation(s)
- Benedetta Pelosi
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden.
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Phyllosphere Community Assembly and Response to Drought Stress on Common Tropical and Temperate Forage Grasses. Appl Environ Microbiol 2021; 87:e0089521. [PMID: 34161142 DOI: 10.1128/aem.00895-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Grasslands represent a critical ecosystem important for global food production, soil carbon storage, and water regulation. Current intensification and expansion practices add to the degradation of grasslands and dramatically increase greenhouse gas emissions and pollution. Thus, new ways to sustain and improve their productivity are needed. Research efforts focus on the plant-leaf microbiome, or phyllosphere, because its microbial members impact ecosystem function by influencing pathogen resistance, plant hormone production, and nutrient availability through processes including nitrogen fixation. However, little is known about grassland phyllospheres and their response to environmental stress. In this study, globally dominant temperate and tropical forage grass species were grown in a greenhouse under current climate conditions and drought conditions that mimic future climate predictions to understand if (i) plant host taxa influence microbial community assembly, (ii) microbial communities respond to drought stress, and (iii) phyllosphere community changes correlate to changes in plant host traits and stress-response strategies. Community analysis using high-resolution sequencing revealed Gammaproteobacteria as the dominant bacterial class, which increased under severe drought stress on both temperate and tropical grasses while overall bacterial community diversity declined. Bacterial community diversity, structure, and response to drought were significantly different between grass species. This community dependence on plant host species correlated with differences in grass species traits, which became more defined under drought stress conditions, suggesting symbiotic evolutionary relationships between plant hosts and their associated microbial community. Further understanding these strategies and the functions microbes provide to plants will help us utilize microbes to promote agricultural and ecosystem productivity in the future. IMPORTANCE Globally important grassland ecosystems are at risk of degradation due to poor management practices compounded by predicted increases in severity and duration of drought over the next century. Finding new ways to support grassland productivity is critical to maintaining their ecological and agricultural benefits. Discerning how grassland microbial communities change in response to climate stress will help us understand how plant-microbe relationships may be useful to sustainably support grasslands in the future. In this study, phyllosphere community diversity and composition were significantly altered under drought conditions. The significance of our research is demonstrating how severe climate stress reduces bacterial community diversity, which previously was directly associated with decreased plant productivity. These findings guide future questions about functional plant-microbe interactions under stress conditions, greatly enhancing our understanding of how bacteria can increase food security by promoting grassland growth and resilience.
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Hymenobacter baengnokdamensis sp. nov., Isolated from the Soil of a Crater Lake in Korea. Curr Microbiol 2020; 77:4167-4173. [PMID: 33025184 DOI: 10.1007/s00284-020-02225-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Accepted: 09/22/2020] [Indexed: 10/23/2022]
Abstract
An aerobic, Gram-stain-negative, non-motile, non-spore-forming, rod-shaped and pink-colored bacterial strain, designated BRD72T, was isolated from a crater lake (Baengnokdam) at the top of Mt. Hallasan in the Republic of Korea. Cells were catalase-positive and oxidase-negative. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that the isolate was a member of the genus Hymenobacter and most closely related to Hymenobacter marinus KJ035T (96.2% similarity). The isolate was found to produce carotenoid pigment, but not flexirubin-type pigment. The predominant fatty acids of strain BRD72T were summed feature 3 (C16:1 ω7c and/or C16:1 ω6c, 21.6%), iso-C15:0 (17.9%), anteiso-C15:0 (13.3%) and summed feature 4 (iso-C17:1 I and/or anteiso-C17:1 B, 11.3%). The major polar lipids were phosphatidylethanolamine, an unidentified amino lipid, and two unidentified aminophospholipids. The main respiratory quinone was menaquinone-7 (MK-7), and the main polyamine was homospermidine. The DNA G+C content was 59.8 mol%. Based on the phylogenetic, physiological, and chemotaxonomic characteristics, strain BRD72T represents a novel species, for which the name Hymenobacter baengnokdamensis sp. nov. is proposed. The type strain is BRD72T (= KCTC 72649T = JCM 33837T).
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