1
|
Harris DF, Rucker HR, Garcia AK, Yang ZY, Chang SD, Feinsilber H, Kaçar B, Seefeldt LC. Ancient nitrogenases are ATP dependent. mBio 2024; 15:e0127124. [PMID: 38869277 PMCID: PMC11253609 DOI: 10.1128/mbio.01271-24] [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: 04/29/2024] [Accepted: 05/03/2024] [Indexed: 06/14/2024] Open
Abstract
Life depends on a conserved set of chemical energy currencies that are relics of early biochemistry. One of these is ATP, a molecule that, when paired with a divalent metal ion such as Mg2+, can be hydrolyzed to support numerous cellular and molecular processes. Despite its centrality to extant biochemistry, it is unclear whether ATP supported the function of ancient enzymes. We investigate the evolutionary necessity of ATP by experimentally reconstructing an ancestral variant of the N2-reducing enzyme nitrogenase. The Proterozoic ancestor is predicted to be ~540-2,300 million years old, post-dating the Great Oxidation Event. Growth rates under nitrogen-fixing conditions are ~80% of those of wild type in Azotobacter vinelandii. In the extant enzyme, the hydrolysis of two MgATP is coupled to electron transfer to support substrate reduction. The ancestor has a strict requirement for ATP with no other nucleotide triphosphate analogs (GTP, ITP, and UTP) supporting activity. Alternative divalent metal ions (Fe2+, Co2+, and Mn2+) support activity with ATP but with diminished activities compared to Mg2+, similar to the extant enzyme. Additionally, it is shown that the ancestor has an identical efficiency in ATP hydrolyzed per electron transferred to the extant of two. Our results provide direct laboratory evidence of ATP usage by an ancient enzyme.IMPORTANCELife depends on energy-carrying molecules to power many sustaining processes. There is evidence that these molecules may predate the rise of life on Earth, but how and when these dependencies formed is unknown. The resurrection of ancient enzymes provides a unique tool to probe the enzyme's function and usage of energy-carrying molecules, shedding light on their biochemical origins. Through experimental reconstruction, this research investigates the ancestral dependence of a nitrogen-fixing enzyme on the energy carrier ATP, a requirement for function in the modern enzyme. We show that the resurrected ancestor does not have generalist nucleotide specificity. Rather, the ancestor has a strict requirement for ATP, like the modern enzyme, with similar function and efficiency. The findings elucidate the early-evolved necessity of energy-yielding molecules, delineating their role in ancient biochemical processes. Ultimately, these insights contribute to unraveling the intricate tapestry of evolutionary biology and the origins of life-sustaining dependencies.
Collapse
Affiliation(s)
- Derek F. Harris
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah, USA
| | - Holly R. Rucker
- Department of Bacteriology, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Amanda K. Garcia
- Department of Bacteriology, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Zhi-Yong Yang
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah, USA
| | - Scott D. Chang
- Department of Bacteriology, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Hannah Feinsilber
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah, USA
| | - Betül Kaçar
- Department of Bacteriology, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Lance C. Seefeldt
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah, USA
| |
Collapse
|
2
|
Mrnjavac N, Degli Esposti M, Mizrahi I, Martin WF, Allen JF. Three enzymes governed the rise of O 2 on Earth. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149495. [PMID: 39004113 PMCID: PMC7616410 DOI: 10.1016/j.bbabio.2024.149495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 06/30/2024] [Accepted: 07/02/2024] [Indexed: 07/16/2024]
Abstract
Current views of O2 accumulation in Earth history depict three phases: The onset of O2 production by ∼2.4 billion years ago; 2 billion years of stasis at ∼1 % of modern atmospheric levels; and a rising phase, starting about 500 million years ago, in which oxygen eventually reached modern values. Purely geochemical mechanisms have been proposed to account for this tripartite time course of Earth oxygenation. In particular the second phase, the long period of stasis between the advent of O2 and the late rise to modern levels, has posed a puzzle. Proposed solutions involve Earth processes (geochemical, ecosystem, day length). Here we suggest that Earth oxygenation was not determined by geochemical processes. Rather it resulted from emergent biological innovations associated with photosynthesis and the activity of only three enzymes: 1) The oxygen evolving complex of cyanobacteria that makes O2; 2) Nitrogenase, with its inhibition by O2 causing two billion years of oxygen level stasis; 3) Cellulose synthase of land plants, which caused mass deposition and burial of carbon, thus removing an oxygen sink and therefore increasing atmospheric O2. These three enzymes are endogenously produced by, and contained within, cells that have the capacity for exponential growth. The catalytic properties of these three enzymes paved the path of Earth's atmospheric oxygenation, requiring no help from Earth other than the provision of water, CO2, salts, colonizable habitats, and sunlight.
Collapse
Affiliation(s)
- Natalia Mrnjavac
- Department of Biology, Institute for Molecular Evolution, Heinrich Heine University of Duesseldorf, Duesseldorf, Germany
| | | | - Itzhak Mizrahi
- Department of Life Sciences, Ben-Gurion University of the Negev and the National Institute for Biotechnology in the Negev, Marcus Family Campus, Be'er-Sheva, Israel
| | - William F Martin
- Department of Biology, Institute for Molecular Evolution, Heinrich Heine University of Duesseldorf, Duesseldorf, Germany
| | - John F Allen
- Research Department of Genetics, Evolution and Environment, University College London, Gower Street, London, UK.
| |
Collapse
|
3
|
Demoulin CF, Sforna MC, Lara YJ, Cornet Y, Somogyi A, Medjoubi K, Grolimund D, Sanchez DF, Tachoueres RT, Addad A, Fadel A, Compère P, Javaux EJ. Polysphaeroides filiformis, a proterozoic cyanobacterial microfossil and implications for cyanobacteria evolution. iScience 2024; 27:108865. [PMID: 38313056 PMCID: PMC10837632 DOI: 10.1016/j.isci.2024.108865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 11/29/2023] [Accepted: 01/08/2024] [Indexed: 02/06/2024] Open
Abstract
Deciphering the fossil record of cyanobacteria is crucial to understand their role in the chemical and biological evolution of the early Earth. They profoundly modified the redox conditions of early ecosystems more than 2.4 Ga ago, the age of the Great Oxidation Event (GOE), and provided the ancestor of the chloroplast by endosymbiosis, leading the diversification of photosynthetic eukaryotes. Here, we analyze the morphology, ultrastructure, chemical composition, and metals distribution of Polysphaeroides filiformis from the 1040-1006 Ma Mbuji-Mayi Supergroup (DR Congo). We evidence trilaminar and bilayered ultrastructures for the sheath and the cell wall, respectively, and the preservation of Ni-tetrapyrrole moieties derived from chlorophyll in intracellular inclusions. This approach allows an unambiguous interpretation of P. filiformis as a branched and multiseriate photosynthetic cyanobacterium belonging to the family of Stigonemataceae. It also provides a possible minimum age for the emergence of multiseriate true branching nitrogen-fixing and probably heterocytous cyanobacteria.
Collapse
Affiliation(s)
- Catherine F Demoulin
- Early Life Traces & Evolution-Astrobiology, UR Astrobiology, University of Liège, 4000 Liège, Belgium
| | - Marie Catherine Sforna
- Early Life Traces & Evolution-Astrobiology, UR Astrobiology, University of Liège, 4000 Liège, Belgium
- Centre de Biophysique Moléculaire, (UPR CNRS 4301), 45071 Orléans, France
| | - Yannick J Lara
- Early Life Traces & Evolution-Astrobiology, UR Astrobiology, University of Liège, 4000 Liège, Belgium
| | - Yohan Cornet
- Early Life Traces & Evolution-Astrobiology, UR Astrobiology, University of Liège, 4000 Liège, Belgium
| | | | | | - Daniel Grolimund
- Paul Scherrer Institut, Swiss Light Source, 5232 Villigen PSI, Switzerland
| | | | | | - Ahmed Addad
- Unité Matériaux et Transformations (UMR CNRS 8207), Université Lille 1 - Sciences et Technologies, 59650 Villeneuve d'Ascq, France
| | - Alexandre Fadel
- Unité Matériaux et Transformations (UMR CNRS 8207), Université Lille 1 - Sciences et Technologies, 59650 Villeneuve d'Ascq, France
| | - Philippe Compère
- Functional and Evolutive Morphology, UR FOCUS, and Center for Applied Research and Education in Microscopy (CAREM-ULiege), University of Liège, 4000 Liège, Belgium
| | - Emmanuelle J Javaux
- Early Life Traces & Evolution-Astrobiology, UR Astrobiology, University of Liège, 4000 Liège, Belgium
| |
Collapse
|
4
|
Pi HW, Chiang YR, Li WH. Mapping Geological Events and Nitrogen Fixation Evolution Onto the Timetree of the Evolution of Nitrogen-Fixation Genes. Mol Biol Evol 2024; 41:msae023. [PMID: 38319744 PMCID: PMC10881105 DOI: 10.1093/molbev/msae023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 11/17/2023] [Accepted: 11/21/2023] [Indexed: 02/08/2024] Open
Abstract
Nitrogen is essential for all organisms, but biological nitrogen fixation (BNF) occurs only in a small fraction of prokaryotes. Previous studies divided nitrogenase-gene-carrying prokaryotes into Groups I to IV and provided evidence that BNF first evolved in bacteria. This study constructed a timetree of the evolution of nitrogen-fixation genes and estimated that archaea evolved BNF much later than bacteria and that nitrogen-fixing cyanobacteria evolved later than 1,900 MYA, considerably younger than the previous estimate of 2,200 MYA. Moreover, Groups III and II/I diverged ∼2,280 MYA, after the Kenorland supercontinent breakup (∼2,500-2,100 MYA) and the Great Oxidation Event (∼2,400-2,100 MYA); Groups III and Vnf/Anf diverged ∼2,086 MYA, after the Yarrabubba impact (∼2,229 MYA); and Groups II and I diverged ∼1,920 MYA, after the Vredefort impact (∼2,023 MYA). In summary, this study provided a timescale of BNF events and discussed the possible effects of geological events on BNF evolution.
Collapse
Affiliation(s)
- Hong-Wei Pi
- Biodiversity Research Center, Academia Sinica, Taipei 115201, Taiwan
- Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung 40227, Taiwan
| | - Yin-Ru Chiang
- Biodiversity Research Center, Academia Sinica, Taipei 115201, Taiwan
| | - Wen-Hsiung Li
- Biodiversity Research Center, Academia Sinica, Taipei 115201, Taiwan
- Department of Ecology and Evolution, University of Chicago, Chicago, IL 60637, USA
| |
Collapse
|
5
|
Mateos K, Chappell G, Klos A, Le B, Boden J, Stüeken E, Anderson R. The evolution and spread of sulfur cycling enzymes reflect the redox state of the early Earth. SCIENCE ADVANCES 2023; 9:eade4847. [PMID: 37418533 PMCID: PMC10328410 DOI: 10.1126/sciadv.ade4847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 02/06/2023] [Accepted: 06/05/2023] [Indexed: 07/09/2023]
Abstract
The biogeochemical sulfur cycle plays a central role in fueling microbial metabolisms, regulating the Earth's redox state, and affecting climate. However, geochemical reconstructions of the ancient sulfur cycle are confounded by ambiguous isotopic signals. We use phylogenetic reconciliation to ascertain the timing of ancient sulfur cycling gene events across the tree of life. Our results suggest that metabolisms using sulfide oxidation emerged in the Archean, but those involving thiosulfate emerged only after the Great Oxidation Event. Our data reveal that observed geochemical signatures resulted not from the expansion of a single type of organism but were instead associated with genomic innovation across the biosphere. Moreover, our results provide the first indication of organic sulfur cycling from the Mid-Proterozoic onwards, with implications for climate regulation and atmospheric biosignatures. Overall, our results provide insights into how the biological sulfur cycle evolved in tandem with the redox state of the early Earth.
Collapse
Affiliation(s)
- Katherine Mateos
- Carleton College, Northfield, MN, USA
- Ocean Sciences Department, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Garrett Chappell
- Carleton College, Northfield, MN, USA
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Aya Klos
- Carleton College, Northfield, MN, USA
| | - Bryan Le
- Carleton College, Northfield, MN, USA
| | - Joanne Boden
- University of St. Andrews, School of Earth and Environmental Sciences, Bute Building, Queen’s Terrace, St Andrews, Fife KY16 9TS, UK
| | - Eva Stüeken
- University of St. Andrews, School of Earth and Environmental Sciences, Bute Building, Queen’s Terrace, St Andrews, Fife KY16 9TS, UK
| | - Rika Anderson
- Carleton College, Northfield, MN, USA
- NASA NExSS Virtual Planetary Laboratory, University of Washington, Seattle, WA, USA
| |
Collapse
|
6
|
Li G, Chen L, Pang K, Tang Q, Wu C, Yuan X, Zhou C, Xiao S. Tonian carbonaceous compressions indicate that Horodyskia is one of the oldest multicellular and coenocytic macro-organisms. Commun Biol 2023; 6:399. [PMID: 37046079 PMCID: PMC10097871 DOI: 10.1038/s42003-023-04740-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 03/21/2023] [Indexed: 04/14/2023] Open
Abstract
Macrofossils with unambiguous biogenic origin and predating the one-billion-year-old multicellular fossils Bangiomorpha and Proterocladus interpreted as crown-group eukaryotes are quite rare. Horodyskia is one of these few macrofossils, and it extends from the early Mesoproterozoic Era to the terminal Ediacaran Period. The biological interpretation of this enigmatic fossil, however, has been a matter of controversy since its discovery in 1982, largely because there was no evidence for the preservation of organic walls. Here we report new carbonaceous compressions of Horodyskia from the Tonian successions (~950-720 Ma) in North China. The macrofossils herein with bona fide organic walls reinforce the biogenicity of Horodyskia. Aided by the new material, we reconstruct Horodyskia as a colonial organism composed of a chain of organic-walled vesicles that likely represent multinucleated (coenocytic) cells of early eukaryotes. Two species of Horodyskia are differentiated on the basis of vesicle sizes, and their co-existence in the Tonian assemblage provides a link between the Mesoproterozoic (H. moniliformis) and the Ediacaran (H. minor) species. Our study thus provides evidence that eukaryotes have acquired macroscopic size through the combination of coenocytism and colonial multicellularity at least ~1.48 Ga, and highlights an exceptionally long range and morphological stasis of this Proterozoic macrofossils.
Collapse
Affiliation(s)
- Guangjin Li
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Lei Chen
- College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, 266590, China.
| | - Ke Pang
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing, 210008, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- University of Chinese Academy of Sciences, Nanjing, 211135, China.
| | - Qing Tang
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, 210023, China
- Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Chengxi Wu
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing, 210008, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xunlai Yuan
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing, 210008, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chuanming Zhou
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing, 210008, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- University of Chinese Academy of Sciences, Nanjing, 211135, China
| | - Shuhai Xiao
- Department of Geosciences and Global Change Center, Virginia Tech, Blacksburg, VA, 24061, USA
| |
Collapse
|
7
|
Gashash EA, Osman NA, Alsahli AA, Hewait HM, Ashmawi AE, Alshallash KS, El-Taher AM, Azab ES, Abd El-Raouf HS, Ibrahim MFM. Effects of Plant-Growth-Promoting Rhizobacteria (PGPR) and Cyanobacteria on Botanical Characteristics of Tomato ( Solanum lycopersicon L.) Plants. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11202732. [PMID: 36297756 PMCID: PMC9610162 DOI: 10.3390/plants11202732] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/04/2022] [Accepted: 10/13/2022] [Indexed: 05/24/2023]
Abstract
Tomatoes are an important agricultural product because they contain high concentrations of bioactive substances, such as folate, ascorbate, polyphenols, and carotenoids, as well as many other essential elements. As a result, tomatoes are thought to be extremely beneficial to human health. Chemical fertilizers and insecticides are routinely utilized to maximize tomato production. In this context, microbial inoculations, particularly those containing PGPR, may be utilized in place of chemical fertilizers and pesticides. In this study, we investigated the effects of PGPR (Bacillus subtilis, and Bacillus amyloliquefaciens) and cyanobacteria when utilized alone, and in conjunction with each other, on the growth, quality, and yield of fresh fruits of tomato plants. The results showed that the inoculation significantly increased all measured parameters of tomato plants compared with the control. Combined use of B. subtilis and B. amyloliquefaciens had a positive impact on tomato yield, increasing fruit yield. Moreover, leaflet anatomical characteristics were altered, with increased thickness of the upper epidermis, lower epidermis, palisade tissue, spongy tissue, and vascular bundles. Tomato fruit quality was improved, as measured by an increased number of fruit per plant (76% increase), fruit weight (g; 33% increase), fruit height (cm; 50% increase), fruit diameter (cm; 50%), total soluble solids (TSS; 26% increase), and ascorbic acid (mg/100 g F.W.; 75% increase), relative to the control, in the first season. In addition, fruit chemical contents (N, P, and K) were increased with inoculation. The results suggest that inoculation with B. subtilis and B. amyloliquefaciens could be successfully used to enhance tomato plant growth and yield.
Collapse
Affiliation(s)
- Ebtesam A. Gashash
- Department of Chemistry, Faculty of Arts and Science in Baljurashi, Baha University, Baha 65635, Saudi Arabia
| | - Nahid A. Osman
- Department of Science and Technology, Ranya Collage, Taif University, Taif 21944, Saudi Arabia
| | - Abdulaziz A. Alsahli
- Department of Botany and Microbiology, Science College, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Heba M. Hewait
- Soils & Water and Environment Research Institute, Agricultural Research Center, Giza 12112, Egypt
| | - Ashmawi E. Ashmawi
- Department of Horticulture, Faculty of Agriculture, Al-Azhar University, Cairo 11651, Egypt
| | - Khalid S. Alshallash
- College of Science and Humanities-Huraymila, Imam Mohammed Bin Saud Islamic University (IMSIU), Riyadh 11432, Saudi Arabia
| | - Ahmed M. El-Taher
- Department of Agricultural Botany, Agriculture Faculty, Al-Azhar University, Cairo 11651, Egypt
| | - Enas S. Azab
- Agricultural Botany Department, Faculty of Agriculture, Suez Canal University, Ismailia 41522, Egypt
| | - Hany S. Abd El-Raouf
- Department of Biology, University College, Taif University, Taif 21944, Saudi Arabia
| | - Mohamed F. M. Ibrahim
- Department of Agricultural Botany, Faculty of Agriculture, Ain Shams University, Cairo 11566, Egypt
| |
Collapse
|
8
|
Jian H, Xu G, Yi Y, Hao Y, Wang Y, Xiong L, Wang S, Liu S, Meng C, Wang J, Zhang Y, Chen C, Feng X, Luo H, Zhang H, Zhang X, Wang L, Wang Z, Deng Z, Xiao X. The origin and impeded dissemination of the DNA phosphorothioation system in prokaryotes. Nat Commun 2021; 12:6382. [PMID: 34737280 PMCID: PMC8569181 DOI: 10.1038/s41467-021-26636-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 10/18/2021] [Indexed: 12/13/2022] Open
Abstract
Phosphorothioate (PT) modification by the dnd gene cluster is the first identified DNA backbone modification and constitute an epigenetic system with multiple functions, including antioxidant ability, restriction modification, and virus resistance. Despite these advantages for hosting dnd systems, they are surprisingly distributed sporadically among contemporary prokaryotic genomes. To address this ecological paradox, we systematically investigate the occurrence and phylogeny of dnd systems, and they are suggested to have originated in ancient Cyanobacteria after the Great Oxygenation Event. Interestingly, the occurrence of dnd systems and prophages is significantly negatively correlated. Further, we experimentally confirm that PT modification activates the filamentous phage SW1 by altering the binding affinity of repressor and the transcription level of its encoding gene. Competition assays, concurrent epigenomic and transcriptomic sequencing subsequently show that PT modification affects the expression of a variety of metabolic genes, which reduces the competitive fitness of the marine bacterium Shewanella piezotolerans WP3. Our findings strongly suggest that a series of negative effects on microorganisms caused by dnd systems limit horizontal gene transfer, thus leading to their sporadic distribution. Overall, our study reveals putative evolutionary scenario of the dnd system and provides novel insights into the physiological and ecological influences of PT modification.
Collapse
Affiliation(s)
- Huahua Jian
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
| | - Guanpeng Xu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yi Yi
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yali Hao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yinzhao Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Lei Xiong
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
| | - Siyuan Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Shunzhang Liu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Canxing Meng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Jiahua Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yue Zhang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Chao Chen
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
| | - Xiaoyuan Feng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Haiwei Luo
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Hao Zhang
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | | | - Lianrong Wang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
| | - Zhijun Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Zixin Deng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Xiang Xiao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China.
| |
Collapse
|
9
|
Parsons C, Stüeken EE, Rosen CJ, Mateos K, Anderson RE. Radiation of nitrogen-metabolizing enzymes across the tree of life tracks environmental transitions in Earth history. GEOBIOLOGY 2021; 19:18-34. [PMID: 33108025 PMCID: PMC7894544 DOI: 10.1111/gbi.12419] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 09/28/2020] [Accepted: 10/05/2020] [Indexed: 05/03/2023]
Abstract
Nitrogen is an essential element to life and exerts a strong control on global biological productivity. The rise and spread of nitrogen-utilizing microbial metabolisms profoundly shaped the biosphere on the early Earth. Here, we reconciled gene and species trees to identify birth and horizontal gene transfer events for key nitrogen-cycling genes, dated with a time-calibrated tree of life, in order to examine the timing of the proliferation of these metabolisms across the tree of life. Our results provide new insights into the evolution of the early nitrogen cycle that expand on geochemical reconstructions. We observed widespread horizontal gene transfer of molybdenum-based nitrogenase back to the Archean, minor horizontal transfer of genes for nitrate reduction in the Archean, and an increase in the proliferation of genes metabolizing nitrite around the time of the Mesoproterozoic (~1.5 Ga). The latter coincides with recent geochemical evidence for a mid-Proterozoic rise in oxygen levels. Geochemical evidence of biological nitrate utilization in the Archean and early Proterozoic may reflect at least some contribution of dissimilatory nitrate reduction to ammonium (DNRA) rather than pure denitrification to N2 . Our results thus help unravel the relative dominance of two metabolic pathways that are not distinguishable with current geochemical tools. Overall, our findings thus provide novel constraints for understanding the evolution of the nitrogen cycle over time and provide insights into the bioavailability of various nitrogen sources in the early Earth with possible implications for the emergence of eukaryotic life.
Collapse
Affiliation(s)
- Chris Parsons
- Carleton CollegeNorthfieldMNUSA
- Massachusetts Institute of TechnologyCambridgeMAUSA
| | | | | | | | - Rika E. Anderson
- Carleton CollegeNorthfieldMNUSA
- NASA NExSS Virtual Planetary LaboratoryUniversity of WashingtonSeattleWAUSA
| |
Collapse
|
10
|
Expression from DIF1-motif promoters of hetR and patS is dependent on HetZ and modulated by PatU3 during heterocyst differentiation. PLoS One 2020; 15:e0232383. [PMID: 32701963 PMCID: PMC7377430 DOI: 10.1371/journal.pone.0232383] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 07/03/2020] [Indexed: 01/01/2023] Open
Abstract
HetR and PatS/PatX-derived peptides are the activator and diffusible inhibitor for cell differentiation and patterning in heterocyst-forming cyanobacteria. HetR regulates target genes via HetR-recognition sites. However, some genes (such as patS/patX) upregulated at the early stage of heterocyst differentiation possess DIF1 (or DIF+) motif (TCCGGA) promoters rather than HetR-recognition sites; hetR possesses both predicted regulatory elements. How HetR controls heterocyst-specific expression from DIF1 motif promoters remains to be answered. This study presents evidence that the expression from DIF1 motif promoters of hetR, patS and patX is more directly dependent on hetZ, a gene regulated by HetR via a HetR-recognition site. The HetR-binding site upstream of hetR is not required for the autoregulation of hetR. PatU3 (3′ portion of PatU) that interacts with HetZ may modulate the expression of hetR, hetZ and patS. These findings contribute to understanding of the mutual regulation of hetR, hetZ-patU and patS/patX in a large group of multicellular cyanobacteria.
Collapse
|
11
|
Kipp MA, Stüeken EE, Gehringer MM, Sterelny K, Scott JK, Forster PI, Strömberg CAE, Buick R. Exploring cycad foliage as an archive of the isotopic composition of atmospheric nitrogen. GEOBIOLOGY 2020; 18:152-166. [PMID: 31769156 DOI: 10.1111/gbi.12374] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/16/2019] [Accepted: 11/05/2019] [Indexed: 06/10/2023]
Abstract
Molecular nitrogen (N2 ) constitutes the majority of Earth's modern atmosphere, contributing ~0.79 bar of partial pressure (pN2 ). However, fluctuations in pN2 may have occurred on 107 -109 year timescales in Earth's past, perhaps altering the isotopic composition of atmospheric nitrogen. Here, we explore an archive that may record the isotopic composition of atmospheric N2 in deep time: the foliage of cycads. Cycads are ancient gymnosperms that host symbiotic N2 -fixing cyanobacteria in modified root structures known as coralloid roots. All extant species of cycads are known to host symbionts, suggesting that this N2 -fixing capacity is perhaps ancestral, reaching back to the early history of cycads in the late Paleozoic. Therefore, if the process of microbial N2 fixation records the δ15 N value of atmospheric N2 in cycad foliage, the fossil record of cycads may provide an archive of atmospheric δ15 N values. To explore this potential proxy, we conducted a survey of wild cycads growing in a range of modern environments to determine whether cycad foliage reliably records the isotopic composition of atmospheric N2 . We find that neither biological nor environmental factors significantly influence the δ15 N values of cycad foliage, suggesting that they provide a reasonably robust record of the δ15 N of atmospheric N2 . Application of this proxy to the record of carbonaceous cycad fossils may not only help to constrain changes in atmospheric nitrogen isotope ratios since the late Paleozoic, but also could shed light on the antiquity of the N2 -fixing symbiosis between cycads and cyanobacteria.
Collapse
Affiliation(s)
- Michael A Kipp
- Department of Earth & Space Sciences, University of Washington, Seattle, WA, USA
- Virtual Planetary Laboratory - NASA Nexus for Exoplanet System Science, Seattle, WA, USA
| | - Eva E Stüeken
- Virtual Planetary Laboratory - NASA Nexus for Exoplanet System Science, Seattle, WA, USA
- School of Earth and Environmental Sciences, University of St. Andrews, St. Andrews, UK
| | - Michelle M Gehringer
- Department of Microbiology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Kim Sterelny
- School of Philosophy, Australian National University, Canberra, ACT, Australia
- School of History, Philosophy, Political Science & International Relations, Victoria University of Wellington, Wellington, New Zealand
| | - John K Scott
- CSIRO Land and Water, Wembley, WA, Australia
- School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Paul I Forster
- Department of Environment & Science, Queensland Herbarium, Toowong, Qld, Australia
| | - Caroline A E Strömberg
- Department of Biology and Burke Museum of Natural History and Culture, University of Washington, Seattle, WA, USA
| | - Roger Buick
- Department of Earth & Space Sciences, University of Washington, Seattle, WA, USA
- Virtual Planetary Laboratory - NASA Nexus for Exoplanet System Science, Seattle, WA, USA
| |
Collapse
|
12
|
Allen JF, Thake B, Martin WF. Nitrogenase Inhibition Limited Oxygenation of Earth's Proterozoic Atmosphere. TRENDS IN PLANT SCIENCE 2019; 24:1022-1031. [PMID: 31447302 DOI: 10.1016/j.tplants.2019.07.007] [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: 04/17/2019] [Revised: 07/10/2019] [Accepted: 07/10/2019] [Indexed: 05/24/2023]
Abstract
Cyanobacteria produced the oxygen that began to accumulate on Earth 2.5 billion years ago, at the dawn of the Proterozoic Eon. By 2.4 billion years ago, the Great Oxidation Event (GOE) marked the onset of an atmosphere containing oxygen. The oxygen content of the atmosphere then remained low for almost 2 billion years. Why? Nitrogenase, the sole nitrogen-fixing enzyme on Earth, controls the entry of molecular nitrogen into the biosphere. Nitrogenase is inhibited in air containing more than 2% oxygen: the concentration of oxygen in the Proterozoic atmosphere. We propose that oxygen inhibition of nitrogenase limited Proterozoic global primary production. Oxygen levels increased when upright terrestrial plants isolated nitrogen fixation in soil from photosynthetic oxygen production in shoots and leaves.
Collapse
Affiliation(s)
- John F Allen
- Research Department of Genetics, Evolution and Environment, Darwin Building, University College London, Gower Street, London WC1E 6BT, UK.
| | - Brenda Thake
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - William F Martin
- Institute of Molecular Evolution, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany
| |
Collapse
|
13
|
Demoulin CF, Lara YJ, Cornet L, François C, Baurain D, Wilmotte A, Javaux EJ. Cyanobacteria evolution: Insight from the fossil record. Free Radic Biol Med 2019; 140:206-223. [PMID: 31078731 PMCID: PMC6880289 DOI: 10.1016/j.freeradbiomed.2019.05.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 03/13/2019] [Accepted: 05/05/2019] [Indexed: 11/07/2022]
Abstract
Cyanobacteria played an important role in the evolution of Early Earth and the biosphere. They are responsible for the oxygenation of the atmosphere and oceans since the Great Oxidation Event around 2.4 Ga, debatably earlier. They are also major primary producers in past and present oceans, and the ancestors of the chloroplast. Nevertheless, the identification of cyanobacteria in the early fossil record remains ambiguous because the morphological criteria commonly used are not always reliable for microfossil interpretation. Recently, new biosignatures specific to cyanobacteria were proposed. Here, we review the classic and new cyanobacterial biosignatures. We also assess the reliability of the previously described cyanobacteria fossil record and the challenges of molecular approaches on modern cyanobacteria. Finally, we suggest possible new calibration points for molecular clocks, and strategies to improve our understanding of the timing and pattern of the evolution of cyanobacteria and oxygenic photosynthesis.
Collapse
Affiliation(s)
- Catherine F Demoulin
- Early Life Traces & Evolution - Astrobiology, UR ASTROBIOLOGY, Geology Department, University of Liège, Liège, Belgium.
| | - Yannick J Lara
- Early Life Traces & Evolution - Astrobiology, UR ASTROBIOLOGY, Geology Department, University of Liège, Liège, Belgium
| | - Luc Cornet
- Early Life Traces & Evolution - Astrobiology, UR ASTROBIOLOGY, Geology Department, University of Liège, Liège, Belgium; Eukaryotic Phylogenomics, InBioS-PhytoSYSTEMS, University of Liège, Liège, Belgium
| | - Camille François
- Early Life Traces & Evolution - Astrobiology, UR ASTROBIOLOGY, Geology Department, University of Liège, Liège, Belgium
| | - Denis Baurain
- Eukaryotic Phylogenomics, InBioS-PhytoSYSTEMS, University of Liège, Liège, Belgium
| | - Annick Wilmotte
- BCCM/ULC Cyanobacteria Collection, InBioS-CIP, Centre for Protein Engineering, University of Liège, Liège, Belgium
| | - Emmanuelle J Javaux
- Early Life Traces & Evolution - Astrobiology, UR ASTROBIOLOGY, Geology Department, University of Liège, Liège, Belgium
| |
Collapse
|
14
|
Timing the Evolutionary Advent of Cyanobacteria and the Later Great Oxidation Event Using Gene Phylogenies of a Sunscreen. mBio 2019; 10:mBio.00561-19. [PMID: 31113897 PMCID: PMC6529634 DOI: 10.1128/mbio.00561-19] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The biosynthesis of the unique cyanobacterial (oxyphotobacterial) indole-phenolic UVA sunscreen, scytonemin, is coded for in a conserved operon that contains both core metabolic genes and accessory, aromatic amino acid biosynthesis genes dedicated to supplying scytonemin's precursors. Comparative genomics shows conservation of this operon in many, but not all, cyanobacterial lineages. Phylogenetic analyses of the operon's aromatic amino acid genes indicate that five of them were recruited into the operon after duplication events of their respective housekeeping cyanobacterial cognates. We combined the fossil record of cyanobacteria and relaxed molecular clock models to obtain multiple estimates of these duplication events, setting a minimum age for the evolutionary advent of scytonemin at 2.1 ± 0.3 billion years. The same analyses were used to estimate the advent of cyanobacteria as a group (and thus the appearance of oxygenic photosynthesis), at 3.6 ± 0.2 billion years before present. Post hoc interpretation of 16S rRNA-based Bayesian analyses was consistent with these estimates. Because of physiological constraints on the use of UVA sunscreens in general, and the biochemical constraints of scytonemin in particular, scytonemin's age must postdate the time when Earth's atmosphere turned oxic, known as the Great Oxidation Event (GOE). Indeed, our biological estimate is in agreement with independent geochemical estimates for the GOE. The difference between the estimated ages of oxygenic photosynthesis and the GOE indicates the long span (on the order of a billion years) of the era of "oxygen oases," when oxygen was available locally but not globally.IMPORTANCE The advent of cyanobacteria, with their invention of oxygenic photosynthesis, and the Great Oxidation Event are arguably among the most important events in the evolutionary history of life on Earth. Oxygen is a significant toxicant to all life, but its accumulation in the atmosphere also enabled the successful development and proliferation of many aerobic organisms, especially metazoans. The currently favored dating of the Great Oxidation Event is based on the geochemical rock record. Similarly, the advent of cyanobacteria is also often drawn from the same estimates because in older rocks paleontological evidence is scarce or has been discredited. Efforts to obtain molecular evolutionary alternatives have offered widely divergent estimates. Our analyses provide a novel means to circumvent these limitations and allow us to estimate the large time gap between the two events.
Collapse
|
15
|
Garlapati D, Chandrasekaran M, Devanesan A, Mathimani T, Pugazhendhi A. Role of cyanobacteria in agricultural and industrial sectors: an outlook on economically important byproducts. Appl Microbiol Biotechnol 2019; 103:4709-4721. [PMID: 31030286 DOI: 10.1007/s00253-019-09811-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 03/29/2019] [Accepted: 03/31/2019] [Indexed: 01/22/2023]
Abstract
Cyanobacteria are potential organisms, which are used as food, feed and fuel. The unique characters of cyanobacteria include short generation times, their ubiquitous presence and efficient nitrogen fixing potential. Cyanobacteria are unique organisms performing photosynthesis, bioremediation of wastewater, high biomass and biofuel productions etc. They are also used in the treatment of industrial and domestic wastewaters for the utilization or removal of ammonia, phosphates and other heavy metals (Cr, Pb, Co, Cu, Zn). Biomasses of cyanobacteria are used as biofertilizers for the improvement of nutrient or mineral status and water-holding capacity of the soil. The secondary metabolites of cyanobacteria are used in pharmaceuticals, nutraceutical and chemical industries. In the industrial sector, value-added products from cyanobacteria such as pigments, enzymes and exopolysaccharides are being produced in large scales for biomedical and health applications. Age-old applications of cyanobacteria in agroecosystems as biofertilizers (Anabaena sp; Nostoc sp.) and in industrial sectors as food products (Spirulina) have motivated the researchers to come up with much more specific applications of cyanobacteria both in agricultural and in industrial sectors. Therefore, considering the effectiveness and efficiency of cyanobacteria, the present review has enlisted the standout qualities of cyanobacteria and their potential applications in agricultural and industrial sectors for the benefit of human beings and environment.
Collapse
Affiliation(s)
- Deviram Garlapati
- National Centre for Coastal Research (NCCR), Ministry of Earth Sciences (MoES), Chennai, Tamil Nadu, 600 100, India
| | - Muthukumar Chandrasekaran
- National Centre for Coastal Research (NCCR), Ministry of Earth Sciences (MoES), Chennai, Tamil Nadu, 600 100, India
| | - ArulAnanth Devanesan
- Department of Food Quality and Safety, Gilat Research Center, Agricultural Research Organization, 85280, Negev, MP, Israel
| | - Thangavel Mathimani
- Department of Energy and Environment, National Institute of Technology, Tiruchirappalli, Tamil Nadu, 620015, India
| | - Arivalagan Pugazhendhi
- Innovative Green Product Synthesis and Renewable Environment Development Research Group, Faculty of Environment and Labour Safety, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
| |
Collapse
|
16
|
Graham LE. Digging deeper: why we need more Proterozoic algal fossils and how to get them. JOURNAL OF PHYCOLOGY 2019; 55:1-6. [PMID: 30270424 DOI: 10.1111/jpy.12790] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 09/24/2018] [Indexed: 06/08/2023]
Abstract
Known Proterozoic algal fossils raise compelling questions about the origin and diversification of cyanobacteria and eukaryotic algae, and their ecological influence in deep time. This Perspectives article describes particular examples of persistent evolutionary and biogeochemical issues whose resolution would be aided by additional algal fossil evidence from Proterozoic deposits, which have been the subjects of recent intensive study. New Proterozoic geosciences literature relevant to the early diversification of algae is surveyed. Previously underappreciated algal traits that might improve taxonomic attributions of fossil remains are highlighted. Processes that phycologists could use to improve detection of algal fossils are recommended. Potential geological sources of new Proterozoic fossils are suggested.
Collapse
Affiliation(s)
- Linda E Graham
- Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, Wisconsin, USA
| |
Collapse
|
17
|
Silverman SN, Kopf SH, Bebout BM, Gordon R, Som SM. Morphological and isotopic changes of heterocystous cyanobacteria in response to N 2 partial pressure. GEOBIOLOGY 2019; 17:60-75. [PMID: 30289610 DOI: 10.1111/gbi.12312] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 07/06/2018] [Accepted: 07/26/2018] [Indexed: 06/08/2023]
Abstract
Earth's atmospheric composition has changed significantly over geologic time. Many redox active atmospheric constituents have left evidence of their presence, while inert constituents such as dinitrogen gas (N2 ) are more elusive. In this study, we examine two potential biological indicators of atmospheric N2 : the morphological and isotopic signatures of heterocystous cyanobacteria. Biological nitrogen fixation constitutes the primary source of fixed nitrogen to the global biosphere and is catalyzed by the oxygen-sensitive enzyme nitrogenase. To protect this enzyme, some filamentous cyanobacteria restrict nitrogen fixation to microoxic cells (heterocysts) while carrying out oxygenic photosynthesis in vegetative cells. Heterocysts terminally differentiate in a pattern that is maintained as the filaments grow, and nitrogen fixation imparts a measurable isotope effect, creating two biosignatures that have previously been interrogated under modern N2 partial pressure (pN2 ) conditions. Here, we examine the effect of variable pN2 on these biosignatures for two species of the filamentous cyanobacterium Anabaena. We provide the first in vivo estimate of the intrinsic isotope fractionation factor of Mo-nitrogenase (εfix = -2.71 ± 0.09‰) and show that, with decreasing pN2 , the net nitrogen isotope fractionation decreases for both species, while the heterocyst spacing decreases for Anabaena cylindrica and remains unchanged for Anabaena variabilis. These results are consistent with the nitrogen fixation mechanisms available in the two species. Application of these quantifiable effects to the geologic record may lead to new paleobarometric measurements for pN2 , ultimately contributing to a better understanding of Earth's atmospheric evolution.
Collapse
Affiliation(s)
- Shaelyn N Silverman
- Department of Geological Sciences, University of Colorado Boulder, Boulder, Colorado
- Blue Marble Space Institute of Science, Seattle, Washington
| | - Sebastian H Kopf
- Department of Geological Sciences, University of Colorado Boulder, Boulder, Colorado
| | - Brad M Bebout
- Exobiology Branch, NASA Ames Research Center, Moffett Field, California
| | - Richard Gordon
- Gulf Specimen Marine Laboratory & Aquarium, Panacea, Florida
- Department of Obstetrics and Gynecology, C. S. Mott Center for Human Growth and Development, Wayne State University, Detroit, Michigan
| | - Sanjoy M Som
- Blue Marble Space Institute of Science, Seattle, Washington
- Exobiology Branch, NASA Ames Research Center, Moffett Field, California
| |
Collapse
|
18
|
After the boring billion and before the freezing millions: evolutionary patterns and innovations in the Tonian Period. Emerg Top Life Sci 2018; 2:161-171. [DOI: 10.1042/etls20170165] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 05/07/2018] [Accepted: 05/15/2018] [Indexed: 11/17/2022]
Abstract
The Tonian Period (ca. 1000–720 Ma) follows the ‘boring billion' in the Mesoproterozoic Era and precedes ‘snowball Earth' glaciations in the Cryogenian Period. It represents a critical transition in Earth history. Geochemical data indicate that the Tonian Period may have witnessed a significant increase in atmospheric pO2 levels and a major transition from predominantly sulfidic to ferruginous mid-depth seawaters. Molecular clock estimates suggest that early animals may have diverged in the Tonian Period, raising the intriguing possibility of coupled environmental changes and evolutionary innovations. The co-evolution of life and its environment during the Tonian Period can be tested against the fossil record by examining diversity trends in the Proterozoic and evolutionary innovations in the Tonian. Compilations of Proterozoic microfossils and macrofossils apparently support a Tonian increase in global taxonomic diversity and morphological range relative to the Mesoproterozoic Era, although this is not reflected in assemblage-level diversity patterns. The fossil record suggests that major eukaryote groups (including Opisthokonta, Amoebozoa, Plantae, and SAR) may have diverged and important evolutionary innovations (e.g. multicellularity and cell differentiation in several groups, eukaryovory, eukaryote biomineralization, and heterocystous cyanobacteria) may have arisen by the Tonian Period, but thus far no convincing animal fossils have been found in the Tonian. Tonian paleontology is still in its nascent stage, and it offers many opportunities to explore Earth-life evolution in this critical geological period.
Collapse
|