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Maloney KM, Halverson GP, Lechte M, Gibson TM, Bui TH, Schiffbauer JD, Laflamme M. The paleoredox context of early eukaryotic evolution: insights from the Tonian Mackenzie Mountains Supergroup, Canada. GEOBIOLOGY 2024; 22:e12598. [PMID: 38700417 DOI: 10.1111/gbi.12598] [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: 11/14/2023] [Revised: 03/18/2024] [Accepted: 03/27/2024] [Indexed: 05/05/2024]
Abstract
Tonian (ca. 1000-720 Ma) marine environments are hypothesised to have experienced major redox changes coinciding with the evolution and diversification of multicellular eukaryotes. In particular, the earliest Tonian stratigraphic record features the colonisation of benthic habitats by multicellular macroscopic algae, which would have been powerful ecosystem engineers that contributed to the oxygenation of the oceans and the reorganisation of biogeochemical cycles. However, the paleoredox context of this expansion of macroalgal habitats in Tonian nearshore marine environments remains uncertain due to limited well-preserved fossils and stratigraphy. As such, the interdependent relationship between early complex life and ocean redox state is unclear. An assemblage of macrofossils including the chlorophyte macroalga Archaeochaeta guncho was recently discovered in the lower Mackenzie Mountains Supergroup in Yukon (Canada), which archives marine sedimentation from ca. 950-775 Ma, permitting investigation into environmental evolution coincident with eukaryotic ecosystem evolution and expansion. Here we present multi-proxy geochemical data from the lower Mackenzie Mountains Supergroup to constrain the paleoredox environment within which these large benthic macroalgae thrived. Two transects show evidence for basin-wide anoxic (ferruginous) oceanic conditions (i.e., high FeHR/FeT, low Fepy/FeHR), with muted redox-sensitive trace metal enrichments and possible seasonal variability. However, the weathering of sulfide minerals in the studied samples may obscure geochemical signatures of euxinic conditions. These results suggest that macroalgae colonized shallow environments in an ocean that remained dominantly anoxic with limited evidence for oxygenation until ca. 850 Ma. Collectively, these geochemical results provide novel insights into the environmental conditions surrounding the evolution and expansion of benthic macroalgae and the eventual dominance of oxygenated oceanic conditions required for the later emergence of animals.
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Affiliation(s)
- Katie M Maloney
- Department of Earth and Planetary Sciences/GEOTOP, McGill University, Montréal, Québec, Canada
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Galen P Halverson
- Department of Earth and Planetary Sciences/GEOTOP, McGill University, Montréal, Québec, Canada
| | - Maxwell Lechte
- Department of Earth and Planetary Sciences/GEOTOP, McGill University, Montréal, Québec, Canada
| | - Timothy M Gibson
- Department of Earth and Planetary Sciences, Yale University, New Haven, Connecticut, USA
| | - Thi Hao Bui
- Department of Earth and Planetary Sciences/GEOTOP, McGill University, Montréal, Québec, Canada
| | - James D Schiffbauer
- Department of Geological Sciences, University of Missouri, Columbia, Missouri, USA
- X-ray Microanalysis Core, University of Missouri, Columbia, Missouri, USA
| | - Marc Laflamme
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, Canada
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2
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Flegr J, Chvátalová V, Příplatová L, Tureček P, Kodym P, Šebánková B, Kaňková Š. Cognitive Effects of Toxoplasma and CMV Infections: A Cross-Sectional Study of 557 Young Adults Considering Modulation by Sex and Rh Factor. Pathogens 2024; 13:363. [PMID: 38787216 PMCID: PMC11124290 DOI: 10.3390/pathogens13050363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 04/17/2024] [Accepted: 04/25/2024] [Indexed: 05/25/2024] Open
Abstract
One-third of humanity harbors a lifelong infection with Toxoplasma gondii, and probably about 80% are infected with human cytomegalovirus (CMV). This study aims to delineate the associations between toxoplasmosis and cognitive abilities and compare these to the associations with CMV. We evaluated the cognitive performance of 557 students, who had been examined for Toxoplasma and CMV infections, using intelligence, memory, and psychomotor tests. The results indicated cognitive impairments in seropositive individuals for both pathogens, with variations in cognitive impact related to sex and the Rh factor. Specifically, Toxoplasma infection was associated with lower IQ in men, whereas CMV was predominantly associated with worse performance by women when testing memory and reaction speeds. Analysis of the antibody concentrations indicated that certain Toxoplasma-associated cognitive detrimental effects may wane (impaired intelligence) or worsen (impaired reaction times) over time following infection. The findings imply that the cognitive impairments caused by both neurotropic pathogens are likely due to pathological changes in the brain rather than from direct manipulative action by the parasites.
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Affiliation(s)
- Jaroslav Flegr
- Laboratory of Evolutionary Biology, Department of Philosophy and History of Sciences, Faculty of Science, Charles University, Viničná 7, 128 00 Prague, Czech Republic (P.T.); (B.Š.); (Š.K.)
| | - Veronika Chvátalová
- Laboratory of Evolutionary Biology, Department of Philosophy and History of Sciences, Faculty of Science, Charles University, Viničná 7, 128 00 Prague, Czech Republic (P.T.); (B.Š.); (Š.K.)
| | - Lenka Příplatová
- Laboratory of Evolutionary Biology, Department of Philosophy and History of Sciences, Faculty of Science, Charles University, Viničná 7, 128 00 Prague, Czech Republic (P.T.); (B.Š.); (Š.K.)
| | - Petr Tureček
- Laboratory of Evolutionary Biology, Department of Philosophy and History of Sciences, Faculty of Science, Charles University, Viničná 7, 128 00 Prague, Czech Republic (P.T.); (B.Š.); (Š.K.)
| | - Petr Kodym
- National Reference Laboratory for Toxoplasmosis, Šrobárova 48, 100 42 Prague, Czech Republic
| | - Blanka Šebánková
- Laboratory of Evolutionary Biology, Department of Philosophy and History of Sciences, Faculty of Science, Charles University, Viničná 7, 128 00 Prague, Czech Republic (P.T.); (B.Š.); (Š.K.)
| | - Šárka Kaňková
- Laboratory of Evolutionary Biology, Department of Philosophy and History of Sciences, Faculty of Science, Charles University, Viničná 7, 128 00 Prague, Czech Republic (P.T.); (B.Š.); (Š.K.)
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3
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Miao L, Yin Z, Knoll AH, Qu Y, Zhu M. 1.63-billion-year-old multicellular eukaryotes from the Chuanlinggou Formation in North China. SCIENCE ADVANCES 2024; 10:eadk3208. [PMID: 38266082 PMCID: PMC10807817 DOI: 10.1126/sciadv.adk3208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 12/21/2023] [Indexed: 01/26/2024]
Abstract
Multicellularity is key to the functional and ecological success of the Eukarya, underpinning much of their modern diversity in both terrestrial and marine ecosystems. Despite the widespread occurrence of simple multicellular organisms among eukaryotes, when this innovation arose remains an open question. Here, we report cellularly preserved multicellular microfossils (Qingshania magnifica) from the ~1635-million-year-old Chuanlinggou Formation, North China. The fossils consist of large uniseriate, unbranched filaments with cell diameters up to 190 micrometers; spheroidal structures, possibly spores, occur within some cells. In combination with spectroscopic characteristics, the large size and morphological complexity of these fossils support their interpretation as eukaryotes, likely photosynthetic, based on comparisons with extant organisms. The occurrence of multicellular eukaryotes in Paleoproterozoic rocks not much younger than those containing the oldest unambiguous evidence of eukaryotes as a whole supports the hypothesis that simple multicellularity arose early in eukaryotic history, as much as a billion years before complex multicellular organisms diversified in the oceans.
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Affiliation(s)
- Lanyun Miao
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Zongjun Yin
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Andrew H. Knoll
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Yuangao Qu
- Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China
| | - Maoyan Zhu
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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Mills DB, Simister RL, Sehein TR, Hallam SJ, Sperling EA, Crowe SA. Constraining the oxygen requirements for modern microbial eukaryote diversity. Proc Natl Acad Sci U S A 2024; 121:e2303754120. [PMID: 38165897 PMCID: PMC10786294 DOI: 10.1073/pnas.2303754120] [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: 03/06/2023] [Accepted: 11/07/2023] [Indexed: 01/04/2024] Open
Abstract
Eukaryotes originated prior to the establishment of modern marine oxygen (O2) levels. According to the body fossil and lipid biomarker records, modern (crown) microbial eukaryote lineages began diversifying in the ocean no later than ~800 Ma. While it has long been predicted that increasing atmospheric O2 levels facilitated the early diversification of microbial eukaryotes, the O2 levels needed to permit this diversification remain unconstrained. Using time-resolved geochemical parameter and gene sequence information from a model marine oxygen minimum zone spanning a range of dissolved O2 levels and redox states, we show that microbial eukaryote taxonomic richness and phylogenetic diversity remain the same until O2 declines to around 2 to 3% of present atmospheric levels, below which these diversity metrics become significantly reduced. Our observations suggest that increasing O2 would have only directly promoted early crown-eukaryote diversity if atmospheric O2 was below 2 to 3% of modern levels when crown-eukaryotes originated and then later met or surpassed this range as crown-eukaryotes diversified. If atmospheric O2 was already consistently at or above 2 to 3% of modern levels by the time that crown-eukaryotes originated, then the subsequent diversification of modern microbial eukaryotes was not directly driven by atmospheric oxygenation.
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Affiliation(s)
- Daniel B. Mills
- Department of Earth and Environmental Sciences, Paleontology and Geobiology, Ludwig-Maximilians-Universität München, 80333Munich, Germany
- Department of Earth and Planetary Sciences, Stanford University, Stanford, CA94305
- The Penn State Extraterrestrial Intelligence Center, The Pennsylvania State University, University Park, PA16802
| | - Rachel L. Simister
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BCV6T 1Z4, Canada
| | - Taylor R. Sehein
- Department of Biological Sciences, Smith College, Northampton, MA01063
| | - Steven J. Hallam
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BCV6T 1Z4, Canada
- Genome Science and Technology Program, University of British Columbia, Vancouver, BCV6T 1Z4, Canada
- Graduate Program in Bioinformatics, University of British Columbia, Vancouver, BCV6T 1Z4, Canada
- Life Sciences Institute, University of British Columbia, Vancouver, BCV6T 1Z3, Canada
- Bradshaw Research Initiative for Minerals and Mining, University of British Columbia, Vancouver, BCV6T 1Z4, Canada
- Ecosystem Services, Commercialization Platforms and Entrepreneurship (ECOSCOPE) Training Program, University of British Columbia, Vancouver, BCV6T 1Z3, Canada
| | - Erik A. Sperling
- Department of Earth and Planetary Sciences, Stanford University, Stanford, CA94305
| | - Sean A. Crowe
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BCV6T 1Z4, Canada
- Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, BCV6T 1Z4, Canada
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Abstract
The origin of modern eukaryotes is one of the key transitions in life's history, and also one of the least understood. Although the fossil record provides the most direct view of this process, interpreting the fossils of early eukaryotes and eukaryote-grade organisms is not straightforward. We present two end-member models for the evolution of modern (i.e., crown) eukaryotes-one in which modern eukaryotes evolved early, and another in which they evolved late-and interpret key fossils within these frameworks, including where they might fit in eukaryote phylogeny and what they may tell us about the evolution of eukaryotic cell biology and ecology. Each model has different implications for understanding the rise of complex life on Earth, including different roles of Earth surface oxygenation, and makes different predictions that future paleontological studies can test.
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Affiliation(s)
- Susannah M Porter
- Department of Earth Science, University of California at Santa Barbara, Santa Barbara, California, USA;
| | - Leigh Anne Riedman
- Department of Earth Science, University of California at Santa Barbara, Santa Barbara, California, USA;
- Earth Research Institute, University of California at Santa Barbara, Santa Barbara, California, USA;
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Yang Z, Ma X, Wang Q, Tian X, Sun J, Zhang Z, Xiao S, De Clerck O, Leliaert F, Zhong B. Phylotranscriptomics unveil a Paleoproterozoic-Mesoproterozoic origin and deep relationships of the Viridiplantae. Nat Commun 2023; 14:5542. [PMID: 37696791 PMCID: PMC10495350 DOI: 10.1038/s41467-023-41137-5] [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: 12/15/2022] [Accepted: 08/23/2023] [Indexed: 09/13/2023] Open
Abstract
The Viridiplantae comprise two main clades, the Chlorophyta (including a diverse array of marine and freshwater green algae) and the Streptophyta (consisting of the freshwater charophytes and the land plants). Lineages sister to core Chlorophyta, informally refer to as prasinophytes, form a grade of mainly planktonic green algae. Recently, one of these lineages, Prasinodermophyta, which is previously grouped with prasinophytes, has been identified as the sister lineage to both Chlorophyta and Streptophyta. Resolving the deep relationships among green plants is crucial for understanding the historical impact of green algal diversity on marine ecology and geochemistry, but has been proven difficult given the ancient timing of the diversification events. Through extensive taxon and gene sampling, we conduct large-scale phylogenomic analyses to resolve deep relationships and reveal the Prasinodermophyta as the lineage sister to Chlorophyta, raising questions about the necessity of classifying the Prasinodermophyta as a distinct phylum. We unveil that incomplete lineage sorting is the main cause of discordance regarding the placement of Prasinodermophyta. Molecular dating analyses suggest that crown-group green plants and crown-group Prasinodermophyta date back to the Paleoproterozoic-Mesoproterozoic. Our study establishes a plausible link between oxygen levels in the Paleoproterozoic-Mesoproterozoic and the origin of Viridiplantae.
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Affiliation(s)
- Zhiping Yang
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xiaoya Ma
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Qiuping Wang
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xiaolin Tian
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Jingyan Sun
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Zhenhua Zhang
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Shuhai Xiao
- Department of Geosciences and Global Change Center, Virginia Tech, Blacksburg, VA, USA
| | - Olivier De Clerck
- Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Ghent, Belgium
| | | | - Bojian Zhong
- College of Life Sciences, Nanjing Normal University, Nanjing, China.
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7
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Kang J, Gill B, Reid R, Zhang F, Xiao S. Nitrate limitation in early Neoproterozoic oceans delayed the ecological rise of eukaryotes. SCIENCE ADVANCES 2023; 9:eade9647. [PMID: 36947611 PMCID: PMC10032604 DOI: 10.1126/sciadv.ade9647] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 02/17/2023] [Indexed: 06/18/2023]
Abstract
The early Neoproterozoic Era witnessed the initial ecological rise of eukaryotes at ca. 800 Ma. To assess whether nitrate availability played an important role in this evolutionary event, we measured nitrogen isotope compositions (δ15N) of marine carbonates from the early Tonian (ca. 1000 Ma to ca. 800 Ma) Huaibei Group in North China. The data reported here fill a critical gap in the δ15N record and indicate nitrate limitation in early Neoproterozoic oceans. A compilation of Proterozoic sedimentary δ15N data reveals a stepwise increase in δ15N values at ~800 Ma. Box model simulations indicate that this stepwise increase likely represents a ~50% increase in marine nitrate availability. Limited nitrate availability in early Neoproterozoic oceans may have delayed the ecological rise of eukaryotes until ~800 Ma when increased nitrate supply, together with other environmental and ecological factors, may have contributed to the transition from prokaryote-dominant to eukaryote-dominant marine ecosystems.
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Affiliation(s)
- Junyao Kang
- Department of Geosciences, Virginia Tech, Blacksburg, VA, USA
- Global Change Center, Virginia Tech, Blacksburg, VA, USA
| | - Benjamin Gill
- Department of Geosciences, Virginia Tech, Blacksburg, VA, USA
- Global Change Center, Virginia Tech, Blacksburg, VA, USA
| | - Rachel Reid
- Department of Geosciences, Virginia Tech, Blacksburg, VA, USA
- Global Change Center, Virginia Tech, Blacksburg, VA, USA
| | - Feifei Zhang
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, and Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing 210023, China
| | - Shuhai Xiao
- Department of Geosciences, Virginia Tech, Blacksburg, VA, USA
- Global Change Center, Virginia Tech, Blacksburg, VA, USA
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8
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Degli Esposti M. The bacterial origin of mitochondria: Incorrect phylogenies and the importance of metabolic traits. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2023; 374:1-35. [PMID: 36858653 DOI: 10.1016/bs.ircmb.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
This article provides an updated review on the evolution of mitochondria from bacteria, which were likely related to extant alphaproteobacteria. Particular attention is given to the timeline of oxygen history on Earth and the entwined phases of eukaryotic evolution that produced the animals that still populate our planet. Mitochondria of early-branching unicellular eukaryotes and plants appear to retain partial or vestigial traits that were directly inherited from the alphaproteobacterial ancestors of the organelles. Most of such traits define the current aerobic physiology of mitochondria. Conversely, the anaerobic traits that would be essential in the syntrophic associations postulated for the evolution of eukaryotic cells are scantly present in extant alphaproteobacteria, and therefore cannot help defining from which bacterial lineage the ancestors of mitochondria originated. This question has recently been addressed quantitatively, reaching the novel conclusion that marine bacteria related to Iodidimonas may be the living relatives of protomitochondria. Additional evidence is presented that either support or does not contrast this novel view of the bacterial origin of mitochondria.
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Abstract
Living systems are built from a small subset of the atomic elements, including the bulk macronutrients (C,H,N,O,P,S) and ions (Mg,K,Na,Ca) together with a small but variable set of trace elements (micronutrients). Here, we provide a global survey of how chemical elements contribute to life. We define five classes of elements: those that are (i) essential for all life, (ii) essential for many organisms in all three domains of life, (iii) essential or beneficial for many organisms in at least one domain, (iv) beneficial to at least some species, and (v) of no known beneficial use. The ability of cells to sustain life when individual elements are absent or limiting relies on complex physiological and evolutionary mechanisms (elemental economy). This survey of elemental use across the tree of life is encapsulated in a web-based, interactive periodic table that summarizes the roles chemical elements in biology and highlights corresponding mechanisms of elemental economy.
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Affiliation(s)
- Kaleigh A Remick
- Department of Microbiology, Cornell University, New York, NY, United States
| | - John D Helmann
- Department of Microbiology, Cornell University, New York, NY, United States.
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10
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Gilmour DJ. Diversity of algae and their biotechnological potential. Adv Microb Physiol 2023; 82:301-321. [PMID: 36948657 DOI: 10.1016/bs.ampbs.2023.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Abstract
This chapter will discuss the diversity of algae and show that the diversity is much greater than just obligately oxygenic photosynthetic algae and that it includes many mixotrophic and heterotrophic organisms that are more similar to the major groups of microorganisms. The photosynthetic groups are seen as part of the plant kingdom, whereas the non-photosynthetic groups are not related to plants at all. The organisation of algal groups has become complex and confusing - The chapter will address the problems within this area of eukaryotic taxonomy. The metabolic diversity of algae and the ability to genetically engineer algae are key components in developing the biotechnology of algae. As more researchers become interested in exploiting algae for a number of industrial products, it is important to understand the relationships between different groups of algae and the relationships of algae with the rest of the living world.
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11
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Eukaryogenesis and oxygen in Earth history. Nat Ecol Evol 2022; 6:520-532. [PMID: 35449457 DOI: 10.1038/s41559-022-01733-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 03/15/2022] [Indexed: 02/07/2023]
Abstract
The endosymbiotic origin of mitochondria during eukaryogenesis has long been viewed as an adaptive response to the oxygenation of Earth's surface environment, presuming a fundamentally aerobic lifestyle for the free-living bacterial ancestors of mitochondria. This oxygen-centric view has been robustly challenged by recent advances in the Earth and life sciences. While the permanent oxygenation of the atmosphere above trace concentrations is now thought to have occurred 2.2 billion years ago, large parts of the deep ocean remained anoxic until less than 0.5 billion years ago. Neither fossils nor molecular clocks correlate the origin of mitochondria, or eukaryogenesis more broadly, to either of these planetary redox transitions. Instead, mitochondria-bearing eukaryotes are consistently dated to between these two oxygenation events, during an interval of pervasive deep-sea anoxia and variable surface-water oxygenation. The discovery and cultivation of the Asgard archaea has reinforced metabolic evidence that eukaryogenesis was initially mediated by syntrophic H2 exchange between an archaeal host and an α-proteobacterial symbiont living under anoxia. Together, these results temporally, spatially and metabolically decouple the earliest stages of eukaryogenesis from the oxygen content of the surface ocean and atmosphere. Rather than reflecting the ancestral metabolic state, obligate aerobiosis in eukaryotes is most probably derived, having only become globally widespread over the past 1 billion years as atmospheric oxygen approached modern levels.
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12
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Maloney KM, Schiffbauer JD, Halverson GP, Xiao S, Laflamme M. Preservation of early Tonian macroalgal fossils from the Dolores Creek Formation, Yukon. Sci Rep 2022; 12:6222. [PMID: 35418588 PMCID: PMC9007953 DOI: 10.1038/s41598-022-10223-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 04/04/2022] [Indexed: 11/30/2022] Open
Abstract
The rise of eukaryotic macroalgae in the late Mesoproterozoic to early Neoproterozoic was a critical development in Earth’s history that triggered dramatic changes in biogeochemical cycles and benthic habitats, ultimately resulting in ecosystems habitable to animals. However, evidence of the diversification and expansion of macroalgae is limited by a biased fossil record. Non-mineralizing organisms are rarely preserved, occurring only in exceptional environments that favor fossilization. Investigating the taphonomy of well-preserved macroalgae will aid in identifying these target environments, allowing ecological trends to be disentangled from taphonomic overprints. Here we describe the taphonomy of macroalgal fossils from the Tonian Dolores Creek Formation (ca. 950 Ma) of northwestern Canada (Yukon Territory) that preserves cm-scale macroalgae. Analytical microscopy, including scanning electron microscopy and tomographic x-ray microscopy, was used to investigate fossil preservation, which was the result of a combination of pyritization and aluminosilicification, similar to accessory mineralization observed in Paleozoic Burgess Shale-type fossils. These new Neoproterozoic fossils help to bridge a gap in the fossil record of early algae, offer a link between the fossil and molecular record, and provide new insights into evolution during the Tonian Period, when many eukaryotic lineages are predicted to have diversified.
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Affiliation(s)
- Katie M Maloney
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada.
| | - James D Schiffbauer
- Department of Geological Sciences, University of Missouri, Columbia, MO, 65211, USA.,X-Ray Microanalysis Core, University of Missouri, Columbia, MO, 65211, USA
| | - Galen P Halverson
- Department of Earth and Planetary Sciences/GEOTOP, McGill University, Montréal, QC, H3A 0E8, Canada
| | - Shuhai Xiao
- Department of Geosciences, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Marc Laflamme
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada
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