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Li H, Li R, Kang J, Hii KS, Mohamed HF, Xu X, Luo Z. Okeanomitos corallinicola gen. and sp. nov. (Nostocales, Cyanobacteria), a new toxic marine heterocyte-forming Cyanobacterium from a coral reef. JOURNAL OF PHYCOLOGY 2024. [PMID: 38943258 DOI: 10.1111/jpy.13473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 05/05/2024] [Accepted: 05/11/2024] [Indexed: 07/01/2024]
Abstract
Cyanobacterial mats supplanting coral and spreading coral diseases in tropical reefs, intensified by environmental shifts caused by human-induced pressures, nutrient enrichment, and global climate change, pose grave risks to the survival of coral ecosystems. In this study, we characterized Okeanomitos corallinicola gen. and sp. nov., a newly discovered toxic marine heterocyte-forming cyanobacterium isolated from a coral reef ecosystem of the South China Sea. Phylogenetic analysis, based on the 16S rRNA gene and the secondary structure of the 16S-23S rRNA intergenic region, placed this species in a clade distinct from closely related genera, that is, Sphaerospermopsis stricto sensu, Raphidiopsis, and Amphiheterocytum. The O. corallinicola is a marine benthic species lacking gas vesicles, distinguishing it from other members of the Aphanizomenonaceae family. The genome of O. corallinicola is large and exhibits diverse functional capabilities, potentially contributing to the resilience and adaptability of coral reef ecosystems. In vitro assays revealed that O. corallinicola demonstrates notable cytotoxic activity against various cancer cell lines, suggesting its potential as a source of novel anticancer compounds. Furthermore, the identification of residual saxitoxin biosynthesis function in the genome of O. corallinicola, a marine cyanobacteria, supports the theory that saxitoxin genes in cyanobacteria and dinoflagellates may have been horizontally transferred between them or may have originated from a shared ancestor. Overall, the identification and characterization of O. corallinicola provides valuable contributions to cyanobacterial taxonomy, offering novel perspectives on complex interactions within coral reef ecosystems.
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Affiliation(s)
- Haiyan Li
- Key Laboratory of Marine Ecological Conservation and Restoration, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
- Institute of Marine Drugs/Guangxi Key Laboratory of Marine Drugs, Guangxi University of Chinese Medicine, Nanning, China
| | - Renhui Li
- College of Life and Environmental Sciences, Wenzhou University, Wenzhou, China
| | - Jianhua Kang
- Key Laboratory of Marine Ecological Conservation and Restoration, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Kieng Soon Hii
- Bachok Marine Research Station, Institute of Ocean and Earth Sciences, University of Malaya, Bachok, Kelantan, Malaysia
| | - Hala F Mohamed
- Botany & Microbiology Department, Faculty of Science, Al-Azhar University (Girls Branch), Cairo, Egypt
| | - Xinya Xu
- Institute of Marine Drugs/Guangxi Key Laboratory of Marine Drugs, Guangxi University of Chinese Medicine, Nanning, China
| | - Zhaohe Luo
- Key Laboratory of Marine Ecological Conservation and Restoration, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
- Observation and Research Station of Coastal Wetland Ecosystem in Beibu Gulf, Ministry of Natural Resources, Beihai, China
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2
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Müller MN, Vicente Ferreira Junior A, Zanardi Lamardo E, Yogui GT, Flores Montes MDJ, Silva MA, Lima EJAC, Rojas LAV, Jannuzzi LGDS, Cunha MDGGDS, Melo PAMDC, Carvalho VPCD, Carneiro YMM, Carreira RDS, Araujo M, Santos LPDS. Finding the needle in a haystack: Evaluation of ecotoxicological effects along the continental shelf break during the Brazilian mysterious oil spill. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 357:124422. [PMID: 38914197 DOI: 10.1016/j.envpol.2024.124422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 06/01/2024] [Accepted: 06/20/2024] [Indexed: 06/26/2024]
Abstract
Oceanic oil spills present significant ecological risks that have the potential to contaminate extensive areas, including coastal regions. The occurrence of the 2019 oil spill event in Brazil resulted in over 3000 km of contaminated beaches and shorelines. While assessing the impact on benthic and beach ecosystems is relatively straightforward due to direct accessibility, evaluating the ecotoxicological effects of open ocean oil spills on the pelagic community is a complex task. Difficulties are associated with the logistical challenges of responding promptly and, in case of the Brazilian mysterious oil spill, to the subsurface propagation of the oil that impeded remote visual detection. An oceanographic expedition was conducted in order to detect and evaluate the impact of this oil spill event along the north-eastern Brazilian continental shelf. The pursuit of dissolved and dispersed oil compounds was accomplished by standard oceanographic methods including seawater polycyclic aromatic hydrocarbons (PAHs) analysis, biomass stable carbon isotope (δ13C), particulate organic carbon to particulate organic nitrogen (POC:PON) ratios, nutrient analysis and ecotoxicological bioassays using the naupliar phase of the copepod Tisbe biminiensis. Significant ecotoxicological effects, reducing naupliar development by 20-40 %, were indicated to be caused by the presence of dispersed oil in the open ocean. The heterogeneous distribution of oil droplets aggravated the direct detection and biochemical indicators for oil are presented and discussed. Our findings serve as a case study for identifying and tracing subsurface propagation of oil, demonstrating the feasibility of utilizing standard oceanographic and ecotoxicological methods to assess the impacts of oil spill events in the open ocean. Ultimately, it encourages the establishment of appropriate measures and responses regarding the liability and regulation of entities to be held accountable for oil spills in the marine environment.
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Affiliation(s)
- Marius Nils Müller
- Department of Oceanography, Federal University of Pernambuco, Recife, PE, 50670-901, Brazil; Macau Environmental Research Institute, Macau University of Science and Technology, Macau SAR, 999078, China.
| | | | - Eliete Zanardi Lamardo
- Department of Oceanography, Federal University of Pernambuco, Recife, PE, 50670-901, Brazil
| | - Gilvan Takeshi Yogui
- Department of Oceanography, Federal University of Pernambuco, Recife, PE, 50670-901, Brazil
| | | | - Marcus André Silva
- Department of Oceanography, Federal University of Pernambuco, Recife, PE, 50670-901, Brazil
| | | | | | | | | | | | | | | | - Renato da Silva Carreira
- Department of Chemistry, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, RJ, 22451-900, Brazil
| | - Moacyr Araujo
- Department of Oceanography, Federal University of Pernambuco, Recife, PE, 50670-901, Brazil
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3
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Henderson LC, Wittmers F, Carlson CA, Worden AZ, Close HG. Variable carbon isotope fractionation of photosynthetic communities over depth in an open-ocean euphotic zone. Proc Natl Acad Sci U S A 2024; 121:e2304613121. [PMID: 38408243 DOI: 10.1073/pnas.2304613121] [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: 04/02/2023] [Accepted: 01/03/2024] [Indexed: 02/28/2024] Open
Abstract
Marine particulate organic carbon (POC) contributes to carbon export, food webs, and sediments, but uncertainties remain in its origins. Globally, variations in stable carbon isotope ratios (δ13C values) of POC between the upper and lower euphotic zones (LEZ) indicate either varying aspects of photosynthetic communities or degradative alteration of POC. During summertime in the subtropical north Atlantic Ocean, we find that δ13C values of the photosynthetic product phytol decreased by 6.3‰ and photosynthetic carbon isotope fractionation (εp) increased by 5.6‰ between the surface and the LEZ-variation as large as that found in the geologic record during major carbon cycle perturbations, but here reflecting vertical variation in δ13C values of photosynthetic communities. We find that simultaneous variations in light intensity and phytoplankton community composition over depth may be important factors not fully accounted for in common models of photosynthetic carbon isotope fractionation. Using additional isotopic and cell count data, we estimate that photosynthetic and non-photosynthetic material (heterotrophs or detritus) contribute relatively constant proportions of POC throughout the euphotic zone but are isotopically more distinct in the LEZ. As a result, the large vertical differences in εp result in significant, but smaller, differences in the δ13C values of total POC across the same depths (2.7‰). Vertical structuring of photosynthetic communities and export potential from the LEZ may vary across current and past ocean ecosystems; thus, LEZ photosynthesis may influence the exported and/or sedimentary δ13C values of both phytol and total organic carbon and affect interpretations of εp over geologic time.
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Affiliation(s)
- Lillian C Henderson
- Department of Ocean Sciences, Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, Miami, FL 33149
| | - Fabian Wittmers
- Faculty of Mathematics and Natural Sciences, Christian-Albrecht University of Kiel, Kiel SH 24118, Germany
| | - Craig A Carlson
- Department of Ecology, Evolution, and Marine Biology/Marine Science Institute, University of California, Santa Barbara, CA 93106
| | - Alexandra Z Worden
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA 02543
| | - Hilary G Close
- Department of Ocean Sciences, Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, Miami, FL 33149
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4
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Jiang HB, Hutchins DA, Ma W, Zhang RF, Wells M, Jiao N, Wang Y, Chai F. Natural ocean iron fertilization and climate variability over geological periods. GLOBAL CHANGE BIOLOGY 2023; 29:6856-6866. [PMID: 37855153 DOI: 10.1111/gcb.16990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 09/20/2023] [Accepted: 09/27/2023] [Indexed: 10/20/2023]
Abstract
Marine primary producers are largely dependent on and shape the Earth's climate, although their relationship with climate varies over space and time. The growth of phytoplankton and associated marine primary productivity in most of the modern global ocean is limited by the supply of nutrients, including the micronutrient iron. The addition of iron via episodic and frequent events drives the biological carbon pump and promotes the sequestration of atmospheric carbon dioxide (CO2 ) into the ocean. However, the dependence between iron and marine primary producers adaptively changes over different geological periods due to the variation in global climate and environment. In this review, we examined the role and importance of iron in modulating marine primary production during some specific geological periods, that is, the Great Oxidation Event (GOE) during the Huronian glaciation, the Snowball Earth Event during the Cryogenian, the glacial-interglacial cycles during the Pleistocene, and the period from the last glacial maximum to the late Holocene. Only the change trend of iron bioavailability and climate in the glacial-interglacial cycles is consistent with the Iron Hypothesis. During the GOE and the Snowball Earth periods, although the bioavailability of iron in the ocean and the climate changed dramatically, the changing trend of many factors contradicted the Iron Hypothesis. By detangling the relationship among marine primary productivity, iron availability and oceanic environments in different geological periods, this review can offer some new insights for evaluating the impact of ocean iron fertilization on removing CO2 from the atmosphere and regulating the climate.
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Affiliation(s)
- Hai-Bo Jiang
- Key Laboratory of Marine Biotechnology of Zhejiang Province, School of Marine Sciences, Ningbo University, Ningbo, Zhejiang, China
- State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, Zhejiang, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, Guangdong, China
| | - David A Hutchins
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Wentao Ma
- State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, Zhejiang, China
| | - Rui-Feng Zhang
- School of Oceanography, Shanghai Jiaotong University, Shanghai, Shanghai, China
| | - Mark Wells
- State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, Zhejiang, China
- School of Marine Sciences, University of Maine, Orono, Maine, USA
| | - Nianzhi Jiao
- State Key Laboratory of Marine Environmental Sciences, Xiamen University, Xiamen, Fujian, China
| | - Yuntao Wang
- State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, Zhejiang, China
| | - Fei Chai
- State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, Zhejiang, China
- State Key Laboratory of Marine Environmental Sciences, Xiamen University, Xiamen, Fujian, China
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5
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Crockford PW, Bar On YM, Ward LM, Milo R, Halevy I. The geologic history of primary productivity. Curr Biol 2023; 33:4741-4750.e5. [PMID: 37827153 DOI: 10.1016/j.cub.2023.09.040] [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: 07/28/2023] [Revised: 09/11/2023] [Accepted: 09/18/2023] [Indexed: 10/14/2023]
Abstract
The rate of primary productivity is a keystone variable in driving biogeochemical cycles today and has been throughout Earth's past.1 For example, it plays a critical role in determining nutrient stoichiometry in the oceans,2 the amount of global biomass,3 and the composition of Earth's atmosphere.4 Modern estimates suggest that terrestrial and marine realms contribute near-equal amounts to global gross primary productivity (GPP).5 However, this productivity balance has shifted significantly in both recent times6 and through deep time.7,8 Combining the marine and terrestrial components, modern GPP fixes ≈250 billion tonnes of carbon per year (Gt C year-1).5,9,10,11 A grand challenge in the study of the history of life on Earth has been to constrain the trajectory that connects present-day productivity to the origin of life. Here, we address this gap by piecing together estimates of primary productivity from the origin of life to the present day. We estimate that ∼1011-1012 Gt C has cumulatively been fixed through GPP (≈100 times greater than Earth's entire carbon stock). We further estimate that 1039-1040 cells have occupied the Earth to date, that more autotrophs than heterotrophs have ever existed, and that cyanobacteria likely account for a larger proportion than any other group in terms of the number of cells. We discuss implications for evolutionary trajectories and highlight the early Proterozoic, which encompasses the Great Oxidation Event (GOE), as the time where most uncertainty exists regarding the quantitative census presented here.
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Affiliation(s)
- Peter W Crockford
- Department of Earth Sciences, Carleton University, Ottawa, ON K1S 5B6, Canada; Department of Earth and Planetary Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel; Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
| | - Yinon M Bar On
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel; Division of Geological Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Luce M Ward
- Department of Geosciences, Smith College, Northampton, MA 01063, USA
| | - Ron Milo
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Itay Halevy
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
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6
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Zhang X, Paoletti MM, Izon G, Fournier GP, Summons RE. Late acquisition of the rTCA carbon fixation pathway by Chlorobi. Nat Ecol Evol 2023; 7:1398-1407. [PMID: 37537385 DOI: 10.1038/s41559-023-02147-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 06/30/2023] [Indexed: 08/05/2023]
Abstract
The reverse tricarboxylic acid (rTCA) cycle is touted as a primordial mode of carbon fixation due to its autocatalytic propensity and oxygen intolerance. Despite this inferred antiquity, however, the earliest rock record affords scant supporting evidence. In fact, based on the chimeric inheritance of rTCA cycle steps within the Chlorobiaceae, even the use of the chemical fossil record of this group is now subject to question. While the 1.64-billion-year-old Barney Creek Formation contains chemical fossils of the earliest known putative Chlorobiaceae-derived carotenoids, interferences from the accompanying hydrocarbon matrix have hitherto precluded the carbon isotope measurements necessary to establish the physiology of the organisms that produced them. Overcoming this obstacle, here we report a suite of compound-specific carbon isotope measurements identifying a cyanobacterially dominated ecosystem featuring heterotrophic bacteria. We demonstrate chlorobactane is 13C-depleted when compared to contemporary equivalents, showing only slight 13C-enrichment over co-existing cyanobacterial carotenoids. The absence of this diagnostic isotopic fingerprint, in turn, confirms phylogenomic hypotheses that call for the late assembly of the rTCA cycle and, thus, the delayed acquisition of autotrophy within the Chlorobiaceae. We suggest that progressive oxygenation of the Earth System caused an increase in the marine sulfate inventory thereby providing the selective pressure to fuel the Neoproterozoic shift towards energy-efficient photoautotrophy within the Chlorobiaceae.
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Affiliation(s)
- Xiaowen Zhang
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
- School of Oceanography, Shanghai Jiao Tong University, Shanghai, China.
| | - Madeline M Paoletti
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Gareth Izon
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Gregory P Fournier
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Roger E Summons
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
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7
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Steensma AK, Shachar-Hill Y, Walker BJ. The carbon-concentrating mechanism of the extremophilic red microalga Cyanidioschyzon merolae. PHOTOSYNTHESIS RESEARCH 2023; 156:247-264. [PMID: 36780115 PMCID: PMC10154280 DOI: 10.1007/s11120-023-01000-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 01/27/2023] [Indexed: 05/03/2023]
Abstract
Cyanidioschyzon merolae is an extremophilic red microalga which grows in low-pH, high-temperature environments. The basis of C. merolae's environmental resilience is not fully characterized, including whether this alga uses a carbon-concentrating mechanism (CCM). To determine if C. merolae uses a CCM, we measured CO2 uptake parameters using an open-path infra-red gas analyzer and compared them to values expected in the absence of a CCM. These measurements and analysis indicated that C. merolae had the gas-exchange characteristics of a CCM-operating organism: low CO2 compensation point, high affinity for external CO2, and minimized rubisco oxygenation. The biomass δ13C of C. merolae was also consistent with a CCM. The apparent presence of a CCM in C. merolae suggests the use of an unusual mechanism for carbon concentration, as C. merolae is thought to lack a pyrenoid and gas-exchange measurements indicated that C. merolae primarily takes up inorganic carbon as carbon dioxide, rather than bicarbonate. We use homology to known CCM components to propose a model of a pH-gradient-based CCM, and we discuss how this CCM can be further investigated.
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Affiliation(s)
- Anne K Steensma
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
- Michigan State University - Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
| | - Yair Shachar-Hill
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
| | - Berkley J Walker
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA.
- Michigan State University - Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, USA.
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8
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Garcia AK, Kędzior M, Taton A, Li M, Young JN, Kaçar B. Effects of RuBisCO and CO 2 concentration on cyanobacterial growth and carbon isotope fractionation. GEOBIOLOGY 2023; 21:390-403. [PMID: 36602111 DOI: 10.1111/gbi.12543] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 11/11/2022] [Accepted: 12/19/2022] [Indexed: 06/17/2023]
Abstract
Carbon isotope biosignatures preserved in the Precambrian geologic record are primarily interpreted to reflect ancient cyanobacterial carbon fixation catalyzed by Form I RuBisCO enzymes. The average range of isotopic biosignatures generally follows that produced by extant cyanobacteria. However, this observation is difficult to reconcile with several environmental (e.g., temperature, pH, and CO2 concentrations), molecular, and physiological factors that likely would have differed during the Precambrian and can produce fractionation variability in contemporary organisms that meets or exceeds that observed in the geologic record. To test a specific range of genetic and environmental factors that may impact ancient carbon isotope biosignatures, we engineered a mutant strain of the model cyanobacterium Synechococcus elongatus PCC 7942 that overexpresses RuBisCO across varying atmospheric CO2 concentrations. We hypothesized that changes in RuBisCO expression would impact the net rates of intracellular CO2 fixation versus CO2 supply, and thus whole-cell carbon isotope discrimination. In particular, we investigated the impacts of RuBisCO overexpression under changing CO2 concentrations on both carbon isotope biosignatures and cyanobacterial physiology, including cell growth and oxygen evolution rates. We found that an increased pool of active RuBisCO does not significantly affect the 13 C/12 C isotopic discrimination (εp ) at all tested CO2 concentrations, yielding εp of ≈ 23‰ for both wild-type and mutant strains at elevated CO2 . We therefore suggest that expected variation in cyanobacterial RuBisCO expression patterns should not confound carbon isotope biosignature interpretation. A deeper understanding of environmental, evolutionary, and intracellular factors that impact cyanobacterial physiology and isotope discrimination is crucial for reconciling microbially driven carbon biosignatures with those preserved in the geologic record.
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Affiliation(s)
- Amanda K Garcia
- Department of Bacteriology, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Mateusz Kędzior
- Department of Bacteriology, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Arnaud Taton
- Division of Biological Sciences, University of California San Diego, La Jolla, California, USA
| | - Meng Li
- School of Oceanography, University of Washington, Seattle, Washington, USA
| | - Jodi N Young
- School of Oceanography, University of Washington, Seattle, Washington, USA
| | - Betül Kaçar
- Department of Bacteriology, University of Wisconsin - Madison, Madison, Wisconsin, USA
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9
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Kupriyanova EV, Pronina NA, Los DA. Adapting from Low to High: An Update to CO 2-Concentrating Mechanisms of Cyanobacteria and Microalgae. PLANTS (BASEL, SWITZERLAND) 2023; 12:1569. [PMID: 37050194 PMCID: PMC10096703 DOI: 10.3390/plants12071569] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/03/2023] [Accepted: 04/04/2023] [Indexed: 06/19/2023]
Abstract
The intracellular accumulation of inorganic carbon (Ci) by microalgae and cyanobacteria under ambient atmospheric CO2 levels was first documented in the 80s of the 20th Century. Hence, a third variety of the CO2-concentrating mechanism (CCM), acting in aquatic photoautotrophs with the C3 photosynthetic pathway, was revealed in addition to the then-known schemes of CCM, functioning in CAM and C4 higher plants. Despite the low affinity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) of microalgae and cyanobacteria for the CO2 substrate and low CO2/O2 specificity, CCM allows them to perform efficient CO2 fixation in the reductive pentose phosphate (RPP) cycle. CCM is based on the coordinated operation of strategically located carbonic anhydrases and CO2/HCO3- uptake systems. This cooperation enables the intracellular accumulation of HCO3-, which is then employed to generate a high concentration of CO2 molecules in the vicinity of Rubisco's active centers compensating up for the shortcomings of enzyme features. CCM functions as an add-on to the RPP cycle while also acting as an important regulatory link in the interaction of dark and light reactions of photosynthesis. This review summarizes recent advances in the study of CCM molecular and cellular organization in microalgae and cyanobacteria, as well as the fundamental principles of its functioning and regulation.
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10
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Garcia AK, Harris DF, Rivier AJ, Carruthers BM, Pinochet-Barros A, Seefeldt LC, Kaçar B. Nitrogenase resurrection and the evolution of a singular enzymatic mechanism. eLife 2023; 12:e85003. [PMID: 36799917 PMCID: PMC9977276 DOI: 10.7554/elife.85003] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 02/16/2023] [Indexed: 02/18/2023] Open
Abstract
The planetary biosphere is powered by a suite of key metabolic innovations that emerged early in the history of life. However, it is unknown whether life has always followed the same set of strategies for performing these critical tasks. Today, microbes access atmospheric sources of bioessential nitrogen through the activities of just one family of enzymes, nitrogenases. Here, we show that the only dinitrogen reduction mechanism known to date is an ancient feature conserved from nitrogenase ancestors. We designed a paleomolecular engineering approach wherein ancestral nitrogenase genes were phylogenetically reconstructed and inserted into the genome of the diazotrophic bacterial model, Azotobacter vinelandii, enabling an integrated assessment of both in vivo functionality and purified nitrogenase biochemistry. Nitrogenase ancestors are active and robust to variable incorporation of one or more ancestral protein subunits. Further, we find that all ancestors exhibit the reversible enzymatic mechanism for dinitrogen reduction, specifically evidenced by hydrogen inhibition, which is also exhibited by extant A. vinelandii nitrogenase isozymes. Our results suggest that life may have been constrained in its sampling of protein sequence space to catalyze one of the most energetically challenging biochemical reactions in nature. The experimental framework established here is essential for probing how nitrogenase functionality has been shaped within a dynamic, cellular context to sustain a globally consequential metabolism.
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Affiliation(s)
- Amanda K Garcia
- Department of Bacteriology, University of Wisconsin–MadisonMadisonUnited States
| | - Derek F Harris
- Department of Chemistry and Biochemistry, Utah State UniversityLoganUnited States
| | - Alex J Rivier
- Department of Bacteriology, University of Wisconsin–MadisonMadisonUnited States
| | - Brooke M Carruthers
- Department of Bacteriology, University of Wisconsin–MadisonMadisonUnited States
| | | | - Lance C Seefeldt
- Department of Chemistry and Biochemistry, Utah State UniversityLoganUnited States
| | - Betül Kaçar
- Department of Bacteriology, University of Wisconsin–MadisonMadisonUnited States
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11
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Huffine CA, Zhao R, Tang YJ, Cameron JC. Role of carboxysomes in cyanobacterial CO 2 assimilation: CO 2 concentrating mechanisms and metabolon implications. Environ Microbiol 2023; 25:219-228. [PMID: 36367380 DOI: 10.1111/1462-2920.16283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 11/09/2022] [Indexed: 11/13/2022]
Abstract
Many carbon-fixing organisms have evolved CO2 concentrating mechanisms (CCMs) to enhance the delivery of CO2 to RuBisCO, while minimizing reactions with the competitive inhibitor, molecular O2 . These distinct types of CCMs have been extensively studied using genetics, biochemistry, cell imaging, mass spectrometry, and metabolic flux analysis. Highlighted in this paper, the cyanobacterial CCM features a bacterial microcompartment (BMC) called 'carboxysome' in which RuBisCO is co-encapsulated with the enzyme carbonic anhydrase (CA) within a semi-permeable protein shell. The cyanobacterial CCM is capable of increasing CO2 around RuBisCO, leading to one of the most efficient processes known for fixing ambient CO2 . The carboxysome life cycle is dynamic and creates a unique subcellular environment that promotes activity of the Calvin-Benson (CB) cycle. The carboxysome may function within a larger cellular metabolon, physical association of functionally coupled proteins, to enhance metabolite channelling and carbon flux. In light of CCMs, synthetic biology approaches have been used to improve enzyme complex for CO2 fixations. Research on CCM-associated metabolons has also inspired biologists to engineer multi-step pathways by providing anchoring points for enzyme cascades to channel intermediate metabolites towards valuable products.
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Affiliation(s)
- Clair A Huffine
- Department of Biochemistry, University of Colorado, Boulder, Colorado, USA
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, Colorado, USA
- Interdisciplinary Quantitative Biology Program (IQ Biology), BioFrontiers Institute, University of Colorado, Boulder, Colorado, USA
| | - Runyu Zhao
- Department of Energy, Environmental and Chemical Engineering, Washington University in Saint Louis, Saint Louis, Missouri, USA
| | - Yinjie J Tang
- Department of Energy, Environmental and Chemical Engineering, Washington University in Saint Louis, Saint Louis, Missouri, USA
| | - Jeffrey C Cameron
- Department of Biochemistry, University of Colorado, Boulder, Colorado, USA
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, Colorado, USA
- National Renewable Energy Laboratory, Golden, Colorado, USA
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Abstract
Cyanobacteria rely on CO2-concentrating mechanisms (CCMs) to grow in today's atmosphere (0.04% CO2). These complex physiological adaptations require ≈15 genes to produce two types of protein complexes: inorganic carbon (Ci) transporters and 100+ nm carboxysome compartments that encapsulate rubisco with a carbonic anhydrase (CA) enzyme. Mutations disrupting any of these genes prohibit growth in ambient air. If any plausible ancestral form-i.e., lacking a single gene-cannot grow, how did the CCM evolve? Here, we test the hypothesis that evolution of the bacterial CCM was "catalyzed" by historically high CO2 levels that decreased over geologic time. Using an E. coli reconstitution of a bacterial CCM, we constructed strains lacking one or more CCM components and evaluated their growth across CO2 concentrations. We expected these experiments to demonstrate the importance of the carboxysome. Instead, we found that partial CCMs expressing CA or Ci uptake genes grew better than controls in intermediate CO2 levels (≈1%) and observed similar phenotypes in two autotrophic bacteria, Halothiobacillus neapolitanus and Cupriavidus necator. To understand how CA and Ci uptake improve growth, we model autotrophy as colimited by CO2 and HCO3-, as both are required to produce biomass. Our experiments and model delineated a viable trajectory for CCM evolution where decreasing atmospheric CO2 induces an HCO3- deficiency that is alleviated by acquisition of CA or Ci uptake, thereby enabling the emergence of a modern CCM. This work underscores the importance of considering physiology and environmental context when studying the evolution of biological complexity.
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Kędzior M, Garcia AK, Li M, Taton A, Adam ZR, Young JN, Kaçar B. Resurrected Rubisco suggests uniform carbon isotope signatures over geologic time. Cell Rep 2022; 39:110726. [PMID: 35476992 DOI: 10.1016/j.celrep.2022.110726] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 02/26/2022] [Accepted: 03/30/2022] [Indexed: 11/30/2022] Open
Abstract
The earliest geochemical indicators of microbes-and the enzymes that powered them-extend back ∼3.8 Ga on Earth. Paleobiologists often attempt to understand these indicators by assuming that the behaviors of extant microbes and enzymes are uniform with those of their predecessors. This consistency in behavior seems at odds with our understanding of the inherent variability of living systems. Here, we examine whether a uniformitarian assumption for an enzyme thought to generate carbon isotope indicators of biological activity, RuBisCO, can be corroborated by independently studying the history of changes recorded within RuBisCO's genetic sequences. We resurrected a Precambrian-age RuBisCO by engineering its ancient DNA inside a cyanobacterium genome and measured the engineered organism's fitness and carbon-isotope-discrimination profile. Results indicate that Precambrian uniformitarian assumptions may be warranted but with important caveats. Experimental studies illuminating early innovations are crucial to explore the molecular foundations of life's earliest traces.
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Affiliation(s)
- Mateusz Kędzior
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA; NASA Center for Early Life and Evolution, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Amanda K Garcia
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA; NASA Center for Early Life and Evolution, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Meng Li
- School of Oceanography, University of Washington, Seattle, WA 98195, USA
| | - Arnaud Taton
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Zachary R Adam
- NASA Center for Early Life and Evolution, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Geosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Jodi N Young
- School of Oceanography, University of Washington, Seattle, WA 98195, USA
| | - Betül Kaçar
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA; NASA Center for Early Life and Evolution, University of Wisconsin-Madison, Madison, WI 53706, USA.
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15
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Piatka DR, Frank AH, Köhler I, Castiglione K, van Geldern R, Barth JAC. Balance of carbon species combined with stable isotope ratios show critical switch towards bicarbonate uptake during cyanobacteria blooms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 807:151067. [PMID: 34673071 DOI: 10.1016/j.scitotenv.2021.151067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 09/14/2021] [Accepted: 10/14/2021] [Indexed: 06/13/2023]
Abstract
Next to water quality deterioration, cyanobacteria blooms can affect turnover of aqueous carbon, including dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and particulate organic carbon (POC). We investigated interactions of these three phases and their stable isotopes in a freshwater pond with periodic cyanobacterial blooms over a period of 23 months. This helped to map turnover and sources of aqueous carbon before, during, and after bloom events. During bloom events POC isotope values (δ13CPOC) increased up to -17.4‰, after aqueous CO2 (CO2(aq)) fell below an atmospheric equilibration value of 412 μatm. Additionally, carbon isotope enrichment between CO2(aq) and POC (εCO2-phyto) ranged from 2.0 to 21.5‰ with lowest fractionations observed at pH values above 8.9. The increase of δ13CPOC and decrease of εCO2-phyto values at low pCO2 and high pH was most likely caused by the activation of the carbon concentrating mechanism (CCM). This mechanism correlated with prevalent assimilation of 13C-enriched HCO3-. Surprisingly, CO2(aq) still contributed more than 50% to the POC pool down to pCO2 values of around 150 μatm. Only after this threshold the reduced εCO2-phyto suggested incorporation of 13C-enriched HCO3-.
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Affiliation(s)
- David R Piatka
- Department of Geography and Geosciences, GeoZentrum Nordbayern, Chair of Applied Geology, Schlossgarten 5, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Germany.
| | - Alexander H Frank
- Department of Geography and Geosciences, GeoZentrum Nordbayern, Chair of Applied Geology, Schlossgarten 5, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Germany
| | - Inga Köhler
- Department of Geography and Geosciences, GeoZentrum Nordbayern, Chair of Applied Geology, Schlossgarten 5, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Germany
| | - Kathrin Castiglione
- Department of Chemical and Biological Engineering, Institute of Bioprocess Engineering, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Germany
| | - Robert van Geldern
- Department of Geography and Geosciences, GeoZentrum Nordbayern, Chair of Applied Geology, Schlossgarten 5, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Germany
| | - Johannes A C Barth
- Department of Geography and Geosciences, GeoZentrum Nordbayern, Chair of Applied Geology, Schlossgarten 5, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Germany
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Huffine CA, Wheeler LC, Wing B, Cameron JC. Computational modeling and evolutionary implications of biochemical reactions in bacterial microcompartments. Curr Opin Microbiol 2021; 65:15-23. [PMID: 34717259 DOI: 10.1016/j.mib.2021.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 10/02/2021] [Indexed: 11/19/2022]
Abstract
Bacterial microcompartments (BMCs) are protein-encapsulated compartments found across at least 23 bacterial phyla. BMCs contain a variety of metabolic processes that share the commonality of toxic or volatile intermediates, oxygen-sensitive enzymes and cofactors, or increased substrate concentration for magnified reaction rates. These compartmentalized reactions have been computationally modeled to explore the encapsulated dynamics, ask evolutionary-based questions, and develop a more systematic understanding required for the engineering of novel BMCs. Many crucial aspects of these systems remain unknown or unmeasured, such as substrate permeabilities across the protein shell, feasibility of pH gradients, and transport rates of associated substrates into the cell. This review explores existing BMC models, dominated in the literature by cyanobacterial carboxysomes, and highlights potentially important areas for exploration.
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Affiliation(s)
- Clair A Huffine
- BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, CO 80309, USA; Department of Biochemistry, University of Colorado, Boulder, CO 80309, USA; Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO 80309, USA; Interdisciplinary Quantitative Biology Program (IQ Biology), BioFrontiers Institute, University of Colorado, Boulder, CO 80309, USA
| | - Lucas C Wheeler
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA
| | - Boswell Wing
- Department of Geological Sciences, Boulder, CO 80309, USA
| | - Jeffrey C Cameron
- Department of Biochemistry, University of Colorado, Boulder, CO 80309, USA; Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO 80309, USA; National Renewable Energy Laboratory, Golden, CO 80401, USA.
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Cyanobacteria and biogeochemical cycles through Earth history. Trends Microbiol 2021; 30:143-157. [PMID: 34229911 DOI: 10.1016/j.tim.2021.05.008] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 05/27/2021] [Accepted: 05/28/2021] [Indexed: 12/13/2022]
Abstract
Cyanobacteria are the only prokaryotes to have evolved oxygenic photosynthesis, transforming the biology and chemistry of our planet. Genomic and evolutionary studies have revolutionized our understanding of early oxygenic phototrophs, complementing and dramatically extending inferences from the geologic record. Molecular clock estimates point to a Paleoarchean origin (3.6-3.2 billion years ago, bya) of the core proteins of Photosystem II (PSII) involved in oxygenic photosynthesis and a Mesoarchean origin (3.2-2.8 bya) for the last common ancestor of modern cyanobacteria. Nonetheless, most extant cyanobacteria diversified after the Great Oxidation Event (GOE), an environmental watershed ca. 2.45 bya made possible by oxygenic photosynthesis. Throughout their evolutionary history, cyanobacteria have played a key role in the global carbon cycle.
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