1
|
Barco RA, Merino N, Lam B, Budnik B, Kaplan M, Wu F, Amend JP, Nealson KH, Emerson D. Comparative proteomics of a versatile, marine, iron-oxidizing chemolithoautotroph. Environ Microbiol 2024; 26:e16632. [PMID: 38861374 DOI: 10.1111/1462-2920.16632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 04/20/2024] [Indexed: 06/13/2024]
Abstract
This study conducted a comparative proteomic analysis to identify potential genetic markers for the biological function of chemolithoautotrophic iron oxidation in the marine bacterium Ghiorsea bivora. To date, this is the only characterized species in the class Zetaproteobacteria that is not an obligate iron-oxidizer, providing a unique opportunity to investigate differential protein expression to identify key genes involved in iron-oxidation at circumneutral pH. Over 1000 proteins were identified under both iron- and hydrogen-oxidizing conditions, with differentially expressed proteins found in both treatments. Notably, a gene cluster upregulated during iron oxidation was identified. This cluster contains genes encoding for cytochromes that share sequence similarity with the known iron-oxidase, Cyc2. Interestingly, these cytochromes, conserved in both Bacteria and Archaea, do not exhibit the typical β-barrel structure of Cyc2. This cluster potentially encodes a biological nanowire-like transmembrane complex containing multiple redox proteins spanning the inner membrane, periplasm, outer membrane, and extracellular space. The upregulation of key genes associated with this complex during iron-oxidizing conditions was confirmed by quantitative reverse transcription-PCR. These findings were further supported by electromicrobiological methods, which demonstrated negative current production by G. bivora in a three-electrode system poised at a cathodic potential. This research provides significant insights into the biological function of chemolithoautotrophic iron oxidation.
Collapse
Affiliation(s)
- Roman A Barco
- Department of Earth Sciences, University of Southern California, Los Angeles, California, USA
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
- Bigelow Laboratory for Ocean Sciences, East Boothbay, Maine, USA
| | - N Merino
- Department of Earth Sciences, University of Southern California, Los Angeles, California, USA
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
- Lawrence Livermore National Lab, Biosciences and Biotechnology Division, Livermore, California, USA
| | - B Lam
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - B Budnik
- Mass Spectrometry and Proteomics Resource Laboratory, Harvard University, Cambridge, Massachusetts, USA
| | - M Kaplan
- Department of Microbiology, University of Chicago, Chicago, Illinois, USA
| | - F Wu
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, Zhejiang, China
| | - J P Amend
- Department of Earth Sciences, University of Southern California, Los Angeles, California, USA
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - K H Nealson
- Department of Earth Sciences, University of Southern California, Los Angeles, California, USA
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - D Emerson
- Bigelow Laboratory for Ocean Sciences, East Boothbay, Maine, USA
| |
Collapse
|
2
|
Baker IR, Girguis PR. Sulfur cycling likely obscures dynamic biologically-driven iron redox cycling in contemporary methane seep environments. ENVIRONMENTAL MICROBIOLOGY REPORTS 2024; 16:e13263. [PMID: 38705733 PMCID: PMC11070330 DOI: 10.1111/1758-2229.13263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Accepted: 04/06/2024] [Indexed: 05/07/2024]
Abstract
Deep-sea methane seeps are amongst the most biologically productive environments on Earth and are often characterised by stable, low oxygen concentrations and microbial communities that couple the anaerobic oxidation of methane to sulfate reduction or iron reduction in the underlying sediment. At these sites, ferrous iron (Fe2+) can be produced by organoclastic iron reduction, methanotrophic-coupled iron reduction, or through the abiotic reduction by sulfide produced by the abundant sulfate-reducing bacteria at these sites. The prevalence of Fe2+in the anoxic sediments, as well as the availability of oxygen in the overlying water, suggests that seeps could also harbour communities of iron-oxidising microbes. However, it is unclear to what extent Fe2+ remains bioavailable and in solution given that the abiotic reaction between sulfide and ferrous iron is often assumed to scavenge all ferrous iron as insoluble iron sulfides and pyrite. Accordingly, we searched the sea floor at methane seeps along the Cascadia Margin for microaerobic, neutrophilic iron-oxidising bacteria, operating under the reasoning that if iron-oxidising bacteria could be isolated from these environments, it could indicate that porewater Fe2+ can persist is long enough for biology to outcompete pyritisation. We found that the presence of sulfate in our enrichment media muted any obvious microbially-driven iron oxidation with most iron being precipitated as iron sulfides. Transfer of enrichment cultures to sulfate-depleted media led to dynamic iron redox cycling relative to abiotic controls and sulfate-containing cultures, and demonstrated the capacity for biogenic iron (oxyhydr)oxides from a methane seep-derived community. 16S rRNA analyses revealed that removing sulfate drastically reduced the diversity of enrichment cultures and caused a general shift from a Gammaproteobacteria-domainated ecosystem to one dominated by Rhodobacteraceae (Alphaproteobacteria). Our data suggest that, in most cases, sulfur cycling may restrict the biological "ferrous wheel" in contemporary environments through a combination of the sulfur-adapted sediment-dwelling ecosystems and the abiotic reactions they influence.
Collapse
Affiliation(s)
- Isabel R. Baker
- Department of Organismic and Evolutionary BiologyHarvard UniversityCambridgeMassachusettsUSA
- Department of Earth and Planetary ScienceJohns Hopkins UniversityBaltimoreMarylandUSA
| | - Peter R. Girguis
- Department of Organismic and Evolutionary BiologyHarvard UniversityCambridgeMassachusettsUSA
| |
Collapse
|
3
|
Yu M, Zhang M, Zeng R, Cheng R, Zhang R, Hou Y, Kuang F, Feng X, Dong X, Li Y, Shao Z, Jin M. Diversity and potential host-interactions of viruses inhabiting deep-sea seamount sediments. Nat Commun 2024; 15:3228. [PMID: 38622147 PMCID: PMC11018836 DOI: 10.1038/s41467-024-47600-1] [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: 10/18/2023] [Accepted: 04/04/2024] [Indexed: 04/17/2024] Open
Abstract
Seamounts are globally distributed across the oceans and form one of the major oceanic biomes. Here, we utilized combined analyses of bulk metagenome and virome to study viral communities in seamount sediments in the western Pacific Ocean. Phylogenetic analyses and the protein-sharing network demonstrate extensive diversity and previously unknown viral clades. Inference of virus-host linkages uncovers extensive interactions between viruses and dominant prokaryote lineages, and suggests that viruses play significant roles in carbon, sulfur, and nitrogen cycling by compensating or augmenting host metabolisms. Moreover, temperate viruses are predicted to be prevalent in seamount sediments, which tend to carry auxiliary metabolic genes for host survivability. Intriguingly, the geographical features of seamounts likely compromise the connectivity of viral communities and thus contribute to the high divergence of viral genetic spaces and populations across seamounts. Altogether, these findings provides knowledge essential for understanding the biogeography and ecological roles of viruses in globally widespread seamounts.
Collapse
Affiliation(s)
- Meishun Yu
- State Key Laboratory Breeding Base of Marine Genetic Resource and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361000, China
| | - Menghui Zhang
- State Key Laboratory Breeding Base of Marine Genetic Resource and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361000, China
| | - Runying Zeng
- State Key Laboratory Breeding Base of Marine Genetic Resource and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361000, China
| | - Ruolin Cheng
- State Key Laboratory Breeding Base of Marine Genetic Resource and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361000, China
| | - Rui Zhang
- Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China
| | - Yanping Hou
- State Key Laboratory Breeding Base of Marine Genetic Resource and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361000, China
| | - Fangfang Kuang
- State Key Laboratory Breeding Base of Marine Genetic Resource and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361000, China
| | - Xuejin Feng
- State Key Laboratory Breeding Base of Marine Genetic Resource and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361000, China
| | - Xiyang Dong
- State Key Laboratory Breeding Base of Marine Genetic Resource and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361000, China
| | - Yinfang Li
- State Key Laboratory Breeding Base of Marine Genetic Resource and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361000, China
| | - Zongze Shao
- State Key Laboratory Breeding Base of Marine Genetic Resource and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361000, China.
| | - Min Jin
- State Key Laboratory Breeding Base of Marine Genetic Resource and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361000, China.
| |
Collapse
|
4
|
Ullrich SR, Fuchs H, Schlömann M. Shedding light on the electron transfer chain of a moderately acidophilic iron oxidizer: characterization of recombinant HiPIP-41, CytC-18 and CytC-78 derived from Ferrovum sp. PN-J47-F6. Res Microbiol 2024; 175:104088. [PMID: 37348744 DOI: 10.1016/j.resmic.2023.104088] [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: 03/29/2023] [Revised: 06/07/2023] [Accepted: 06/07/2023] [Indexed: 06/24/2023]
Abstract
Efficient electron transfer from the donor to the acceptor couple presents a necessary requirement for acidophilic and neutrophilic iron oxidizers due to the low energy yield of aerobic ferrous iron oxidation. Involved periplasmic electron carriers are very diverse in these bacteria and show adaptations to the respective thermodynamic constraints such as a more positive redox potential reported for extreme acidophilic Acidithiobacillus spp. Respiratory chain candidates of moderately acidophilic members of the genus Ferrovum share similarities with both their neutrophilic iron oxidizing relatives and the more distantly related Acidithiobacillus spp. We examined our previous omics-based conclusions on the potential electron transfer chain in Ferrovum spp. by characterizing the three redox protein candidates CytC-18, CytC-78 and HiPIP-41 of strain PN-J47-F6 which were produced as recombinant proteins in Eschericha coli. UV/Vis-based redox assays suggested that HiPIP-41 has a very positive redox potential while redox potentials of CytC-18 and CytC-78 are more negative than their counterparts in Acidithiobacillus spp. Far Western dot blotting demonstrated interactions between all three recombinant redox proteins while redox assays showed the electron transfer from HiPIP-41 to either of the cytochromes. Altogether, CytC-18, CytC-78 and HiPIP-41 indeed represent very likely candidates of the electron transfer in Ferrovum sp. PN-J4-F6.
Collapse
Affiliation(s)
- Sophie R Ullrich
- TU Bergakademie Freiberg, Institute for Biological Sciences, Leipziger Strasse 29, Freiberg, Germany.
| | - Helena Fuchs
- TU Bergakademie Freiberg, Institute for Biological Sciences, Leipziger Strasse 29, Freiberg, Germany
| | - Michael Schlömann
- TU Bergakademie Freiberg, Institute for Biological Sciences, Leipziger Strasse 29, Freiberg, Germany
| |
Collapse
|
5
|
Hribovšek P, Olesin Denny E, Dahle H, Mall A, Øfstegaard Viflot T, Boonnawa C, Reeves EP, Steen IH, Stokke R. Putative novel hydrogen- and iron-oxidizing sheath-producing Zetaproteobacteria thrive at the Fåvne deep-sea hydrothermal vent field. mSystems 2023; 8:e0054323. [PMID: 37921472 PMCID: PMC10734525 DOI: 10.1128/msystems.00543-23] [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: 06/20/2023] [Accepted: 10/02/2023] [Indexed: 11/04/2023] Open
Abstract
IMPORTANCE Knowledge on microbial iron oxidation is important for understanding the cycling of iron, carbon, nitrogen, nutrients, and metals. The current study yields important insights into the niche sharing, diversification, and Fe(III) oxyhydroxide morphology of Ghiorsea, an iron- and hydrogen-oxidizing Zetaproteobacteria representative belonging to Zetaproteobacteria operational taxonomic unit 9. The study proposes that Ghiorsea exhibits a more extensive morphology of Fe(III) oxyhydroxide than previously observed. Overall, the results increase our knowledge on potential drivers of Zetaproteobacteria diversity in iron microbial mats and can eventually be used to develop strategies for the cultivation of sheath-forming Zetaproteobacteria.
Collapse
Affiliation(s)
- Petra Hribovšek
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
- Department of Earth Science, University of Bergen, Bergen, Norway
| | - Emily Olesin Denny
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
- Department of Biological Sciences, University of Bergen, Bergen, Norway
- Computational Biology Unit, University of Berge, Bergen, Norway
| | - Håkon Dahle
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
- Department of Biological Sciences, University of Bergen, Bergen, Norway
- Computational Biology Unit, University of Berge, Bergen, Norway
| | - Achim Mall
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Thomas Øfstegaard Viflot
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
- Department of Earth Science, University of Bergen, Bergen, Norway
| | - Chanakan Boonnawa
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
- Department of Earth Science, University of Bergen, Bergen, Norway
| | - Eoghan P. Reeves
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
- Department of Earth Science, University of Bergen, Bergen, Norway
| | - Ida Helene Steen
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Runar Stokke
- Centre for Deep Sea Research, University of Bergen, Bergen, Norway
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| |
Collapse
|
6
|
Hoover RL, Keffer JL, Polson SW, Chan CS. Gallionellaceae pangenomic analysis reveals insight into phylogeny, metabolic flexibility, and iron oxidation mechanisms. mSystems 2023; 8:e0003823. [PMID: 37882557 PMCID: PMC10734462 DOI: 10.1128/msystems.00038-23] [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: 01/25/2023] [Accepted: 09/20/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE Neutrophilic iron-oxidizing bacteria (FeOB) produce copious iron (oxyhydr)oxides that can profoundly influence biogeochemical cycles, notably the fate of carbon and many metals. To fully understand environmental microbial iron oxidation, we need a thorough accounting of iron oxidation mechanisms. In this study, we show the Gallionellaceae FeOB genomes encode both characterized iron oxidases as well as uncharacterized multiheme cytochromes (MHCs). MHCs are predicted to transfer electrons from extracellular substrates and likely confer metabolic capabilities that help Gallionellaceae occupy a range of different iron- and mineral-rich niches. Gallionellaceae appear to specialize in iron oxidation, so it would be advantageous for them to have multiple mechanisms to oxidize various forms of iron, given the many iron minerals on Earth, as well as the physiological and kinetic challenges faced by FeOB. The multiple iron/mineral oxidation mechanisms may help drive the widespread ecological success of Gallionellaceae.
Collapse
Affiliation(s)
- Rene L. Hoover
- Microbiology Graduate Program, University of Delaware, Newark, Delaware, USA
- Department of Earth Sciences, University of Delaware, Newark, Delaware, USA
| | - Jessica L. Keffer
- Department of Earth Sciences, University of Delaware, Newark, Delaware, USA
| | - Shawn W. Polson
- Department of Computer and Information Sciences, University of Delaware, Newark, Delaware, USA
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, Delaware, USA
| | - Clara S. Chan
- Microbiology Graduate Program, University of Delaware, Newark, Delaware, USA
- Department of Earth Sciences, University of Delaware, Newark, Delaware, USA
- School of Marine Science and Policy, University of Delaware, Newark, Delaware, USA
| |
Collapse
|
7
|
Chan CS, Dykes GE, Hoover RL, Limmer MA, Seyfferth AL. Gallionellaceae in rice root plaque: metabolic roles in iron oxidation, nutrient cycling, and plant interactions. Appl Environ Microbiol 2023; 89:e0057023. [PMID: 38009924 PMCID: PMC10734482 DOI: 10.1128/aem.00570-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 09/18/2023] [Indexed: 11/29/2023] Open
Abstract
IMPORTANCE In waterlogged soils, iron plaque forms a reactive barrier between the root and soil, collecting phosphate and metals such as arsenic and cadmium. It is well established that iron-reducing bacteria solubilize iron, releasing these associated elements. In contrast, microbial roles in plaque formation have not been clear. Here, we show that there is a substantial population of iron oxidizers in plaque, and furthermore, that these organisms (Sideroxydans and Gallionella) are distinguished by genes for plant colonization and nutrient fixation. Our results suggest that iron-oxidizing and iron-reducing bacteria form and remodel iron plaque, making it a dynamic system that represents both a temporary sink for elements (P, As, Cd, C, etc.) as well as a source. In contrast to abiotic iron oxidation, microbial iron oxidation results in coupled Fe-C-N cycling, as well as microbe-microbe and microbe-plant ecological interactions that need to be considered in soil biogeochemistry, ecosystem dynamics, and crop management.
Collapse
Affiliation(s)
- Clara S. Chan
- Department of Earth Sciences, University of Delaware, Newark, Delaware, USA
- School of Marine Science and Policy, University of Delaware, Newark, Delaware, USA
- Microbiology Graduate Program, University of Delaware, Newark, Delaware, USA
- Delaware Biotechnology Institute, Newark, Delaware, USA
| | - Gretchen E. Dykes
- Microbiology Graduate Program, University of Delaware, Newark, Delaware, USA
- Delaware Biotechnology Institute, Newark, Delaware, USA
- Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware, USA
| | - Rene L. Hoover
- Department of Earth Sciences, University of Delaware, Newark, Delaware, USA
- Microbiology Graduate Program, University of Delaware, Newark, Delaware, USA
- Delaware Biotechnology Institute, Newark, Delaware, USA
| | - Matt A. Limmer
- Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware, USA
| | - Angelia L. Seyfferth
- Department of Earth Sciences, University of Delaware, Newark, Delaware, USA
- Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware, USA
| |
Collapse
|
8
|
Li L, Liu Z, Meng D, Liu Y, Liu T, Jiang C, Yin H. Sequence similarity network and protein structure prediction offer insights into the evolution of microbial pathways for ferrous iron oxidation. mSystems 2023; 8:e0072023. [PMID: 37768051 PMCID: PMC10654088 DOI: 10.1128/msystems.00720-23] [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: 07/11/2023] [Accepted: 08/09/2023] [Indexed: 09/29/2023] Open
Abstract
IMPORTANCE Microbial Fe(II) oxidation is a crucial process that harnesses and converts the energy available in Fe, contributing significantly to global element cycling. However, there are still many aspects of this process that remain unexplored. In this study, we utilized a combination of comparative genomics, sequence similarity network analysis, and artificial intelligence-driven structure modeling methods to address the lack of structural information on Fe(II) oxidation proteins and offer a comprehensive perspective on the evolution of Fe(II) oxidation pathways. Our findings suggest that several microbial Fe(II) oxidation pathways currently known may have originated within classes Gammaproteobacteria and Betaproteobacteria.
Collapse
Affiliation(s)
- Liangzhi Li
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Zhenghua Liu
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Delong Meng
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Yongjun Liu
- Hunan Tobacco Science Institute, Changsha, China
| | - Tianbo Liu
- Hunan Tobacco Science Institute, Changsha, China
| | - Chengying Jiang
- University of Chinese Academy of Sciences, Beijing, China
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Huaqun Yin
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| |
Collapse
|
9
|
Mugge RL, Moseley RD, Hamdan LJ. Substrate Specificity of Biofilms Proximate to Historic Shipwrecks. Microorganisms 2023; 11:2416. [PMID: 37894074 PMCID: PMC10608953 DOI: 10.3390/microorganisms11102416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 09/13/2023] [Accepted: 09/25/2023] [Indexed: 10/29/2023] Open
Abstract
The number of built structures on the seabed, such as shipwrecks, energy platforms, and pipelines, is increasing in coastal and offshore regions. These structures, typically composed of steel or wood, are substrates for microbial attachment and biofilm formation. The success of biofilm growth depends on substrate characteristics and local environmental conditions, though it is unclear which feature is dominant in shaping biofilm microbiomes. The goal of this study was to understand the substrate- and site-specific impacts of built structures on short-term biofilm composition and functional potential. Seafloor experiments were conducted wherein steel and wood surfaces were deployed for four months at distances extending up to 115 m away from three historic (>50 years old) shipwrecks in the Gulf of Mexico. DNA from biofilms on the steel and wood was extracted, and metagenomes were sequenced on an Illumina NextSeq. A bioinformatics analysis revealed that the taxonomic composition was significantly different between substrates and sites, with substrate being the primary determining factor. Regardless of site, the steel biofilms had a higher abundance of genes related to biofilm formation, and sulfur, iron, and nitrogen cycling, while the wood biofilms showed a higher abundance of manganese cycling and methanol oxidation genes. This study demonstrates how substrate composition shapes biofilm microbiomes and suggests that marine biofilms may contribute to nutrient cycling at depth. Analyzing the marine biofilm microbiome provides insight into the ecological impact of anthropogenic structures on the seabed.
Collapse
Affiliation(s)
- Rachel L. Mugge
- U.S. Naval Research Laboratory, Ocean Sciences Division, Stennis Space Center, MS 39529, USA;
| | - Rachel D. Moseley
- School of Ocean Science and Engineering, University of Southern Mississippi, Ocean Springs, MS 39564, USA
| | - Leila J. Hamdan
- School of Ocean Science and Engineering, University of Southern Mississippi, Ocean Springs, MS 39564, USA
| |
Collapse
|
10
|
Zhang D, Li X, Wu Y, Xu X, Liu Y, Shi B, Peng Y, Dai D, Sha Z, Zheng J. Microbe-driven elemental cycling enables microbial adaptation to deep-sea ferromanganese nodule sediment fields. MICROBIOME 2023; 11:160. [PMID: 37491386 PMCID: PMC10367259 DOI: 10.1186/s40168-023-01601-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 06/17/2023] [Indexed: 07/27/2023]
Abstract
BACKGROUND Ferromanganese nodule-bearing deep-sea sediments cover vast areas of the ocean floor, representing a distinctive habitat in the abyss. These sediments harbor unique conditions characterized by high iron concentration and low degradable nutrient levels, which pose challenges to the survival and growth of most microorganisms. While the microbial diversity in ferromanganese nodule-associated sediments has been surveyed several times, little is known about the functional capacities of the communities adapted to these unique habitats. RESULTS Seven sediment samples collected adjacent to ferromanganese nodules from the Clarion-Clipperton Fracture Zone (CCFZ) in the eastern Pacific Ocean were subjected to metagenomic analysis. As a result, 179 high-quality metagenome-assembled genomes (MAGs) were reconstructed and assigned to 21 bacterial phyla and 1 archaeal phylum, with 88.8% of the MAGs remaining unclassified at the species level. The main mechanisms of resistance to heavy metals for microorganisms in sediments included oxidation (Mn), reduction (Cr and Hg), efflux (Pb), synergy of reduction and efflux (As), and synergy of oxidation and efflux (Cu). Iron, which had the highest content among all metallic elements, may occur mainly as Fe(III) that potentially functioned as an electron acceptor. We found that microorganisms with a diverse array of CAZymes did not exhibit higher community abundance. Instead, microorganisms mainly obtained energy from oxidation of metal (e.g., Mn(II)) and sulfur compounds using oxygen or nitrate as an electron acceptor. Chemolithoautotrophic organisms (Thaumarchaeota and Nitrospirota phyla) were found to be potential manganese oxidizers. The functional profile analysis of the dominant microorganisms further indicated that utilization of inorganic nutrients by redox reactions (rather than organic nutrient metabolism) is a major adaptive strategy used by microorganisms to support their survival in the ferromanganese nodule sediments. CONCLUSIONS This study provides a comprehensive metagenomic analysis of microbes inhabiting metal-rich ferromanganese nodule sediments. Our results reveal extensive redundancy across taxa for pathways of metal resistance and transformation, the highly diverse mechanisms used by microbes to obtain nutrition, and their participation in various element cycles in these unique environments. Video Abstract.
Collapse
Affiliation(s)
- Dechao Zhang
- Qingdao Key Laboratory of Marine Biodiversity and Conservation, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Geology, Laoshan Laboratory, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xudong Li
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yuehong Wu
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources & Second Institute of Oceanography, Ministry of Natural Resources, 310012, Hangzhou, China
| | - Xuewei Xu
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources & Second Institute of Oceanography, Ministry of Natural Resources, 310012, Hangzhou, China
| | - Yanxia Liu
- Laboratory for Marine Geology, Laoshan Laboratory, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Benze Shi
- Qingdao Key Laboratory of Marine Biodiversity and Conservation, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Geology, Laoshan Laboratory, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yujie Peng
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, 430070, China
| | - Dadong Dai
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhongli Sha
- Qingdao Key Laboratory of Marine Biodiversity and Conservation, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
- Laboratory for Marine Geology, Laoshan Laboratory, Qingdao, 266237, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Jinshui Zheng
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China.
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, 430070, China.
| |
Collapse
|
11
|
Corbera-Rubio F, Laureni M, Koudijs N, Müller S, van Alen T, Schoonenberg F, Lücker S, Pabst M, van Loosdrecht MCM, van Halem D. Meta-omics profiling of full-scale groundwater rapid sand filters explains stratification of iron, ammonium and manganese removals. WATER RESEARCH 2023; 233:119805. [PMID: 36868119 DOI: 10.1016/j.watres.2023.119805] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/30/2023] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
Rapid sand filters (RSF) are an established and widely applied technology for groundwater treatment. Yet, the underlying interwoven biological and physical-chemical reactions controlling the sequential removal of iron, ammonia and manganese remain poorly understood. To resolve the contribution and interactions between the individual reactions, we studied two full-scale drinking water treatment plant configurations, namely (i) one dual-media (anthracite and quartz sand) filter and (ii) two single-media (quartz sand) filters in series. In situ and ex situ activity tests were combined with mineral coating characterization and metagenome-guided metaproteomics along the depth of each filter. Both plants exhibited comparable performances and process compartmentalization, with most of ammonium and manganese removal occurring only after complete iron depletion. The homogeneity of the media coating and genome-based microbial composition within each compartment highlighted the effect of backwashing, namely the complete vertical mixing of the filter media. In stark contrast to this homogeneity, the removal of the contaminants was strongly stratified within each compartment, and decreased along the filter height. This apparent and longstanding conflict was resolved by quantifying the expressed proteome at different filter heights, revealing a consistent stratification of proteins catalysing ammonia oxidation and protein-based relative abundances of nitrifying genera (up to 2 orders of magnitude difference between top and bottom samples). This implies that microorganisms adapt their protein pool to the available nutrient load at a faster rate than the backwash mixing frequency. Ultimately, these results show the unique and complementary potential of metaproteomics to understand metabolic adaptations and interactions in highly dynamic ecosystems.
Collapse
Affiliation(s)
| | - Michele Laureni
- Delft University of Technology, van der Maasweg 9, HZ Delft 2629, The Netherlands.
| | - Nienke Koudijs
- Delft University of Technology, van der Maasweg 9, HZ Delft 2629, The Netherlands
| | - Simon Müller
- Delft University of Technology, van der Maasweg 9, HZ Delft 2629, The Netherlands
| | - Theo van Alen
- Department of Microbiology, RIBES, Radboud University, Heyendaalseweg 135, AJ Nijmegen 6525, The Netherlands
| | | | - Sebastian Lücker
- Department of Microbiology, RIBES, Radboud University, Heyendaalseweg 135, AJ Nijmegen 6525, The Netherlands
| | - Martin Pabst
- Delft University of Technology, van der Maasweg 9, HZ Delft 2629, The Netherlands
| | | | - Doris van Halem
- Delft University of Technology, van der Maasweg 9, HZ Delft 2629, The Netherlands
| |
Collapse
|
12
|
Olmsted CN, Ort R, Tran PQ, McDaniel EA, Roden EE, Bond DR, He S, McMahon KD. Environmental predictors of electroactive bacterioplankton in small boreal lakes. Environ Microbiol 2023; 25:705-720. [PMID: 36529539 DOI: 10.1111/1462-2920.16314] [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: 03/25/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
Extracellular electron transfer (EET) by electroactive bacteria in anoxic soils and sediments is an intensively researched subject, but EET's function in planktonic ecology has been less considered. Following the discovery of an unexpectedly high prevalence of EET genes in a bog lake's bacterioplankton, we hypothesized that the redox capacities of dissolved organic matter (DOM) enrich for electroactive bacteria by mediating redox chemistry. We developed the bioinformatics pipeline FEET (Find EET) to identify and summarize predicted EET protein-encoding genes from metagenomics data. We then applied FEET to 36 bog and thermokarst lakes and correlated gene occurrence with environmental data to test our predictions. Our results provide indirect evidence that DOM may participate in bacterioplankton EET. We found a similarly high prevalence of genes encoding putative EET proteins in most of these lakes, where oxidative EET strongly correlated with DOM. Numerous novel clusters of multiheme cytochromes that may enable EET were identified. Taxa previously not considered EET-capable were found to carry EET genes. We propose that EET and DOM interactions are of ecologically important to bacterioplankton in small boreal lakes, and that EET, particularly by methylotrophs and anoxygenic phototrophs, should be further studied and incorporated into methane emission models of melting permafrost.
Collapse
Affiliation(s)
- Charles N Olmsted
- Department of Molecular and Environmental Toxicology, University of Wisconsin - Madison, Madison, Wisconsin, USA
- Trout Lake Station, Center for Limnology, University of Wisconsin - Madison, Boulder, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Roger Ort
- Trout Lake Station, Center for Limnology, University of Wisconsin - Madison, Boulder, Wisconsin, USA
| | - Patricia Q Tran
- Department of Bacteriology, University of Wisconsin - Madison, Madison, Wisconsin, USA
- Department of Integrative Biology, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Elizabeth A McDaniel
- Department of Bacteriology, University of Wisconsin - Madison, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Eric E Roden
- Department of Geoscience, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Daniel R Bond
- Department of Plant and Microbial Biology and BioTechnology Institute, University of Minnesota, St. Paul, Minnesota, USA
| | - Shaomei He
- Department of Bacteriology, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Katherine D McMahon
- Department of Bacteriology, University of Wisconsin - Madison, Madison, Wisconsin, USA
- Department of Civil and Environmental Engineering, University of Wisconsin - Madison, Madison, Wisconsin, USA
| |
Collapse
|
13
|
Suarez C, Hackl T, Wilen BM, Persson F, Hagelia P, Jetten MSM, Dalcin Martins P. Novel and unusual genes for nitrogen and metal cycling in Planctomycetota- and KSB1-affiliated metagenome-assembled genomes reconstructed from a marine subsea tunnel. FEMS Microbiol Lett 2023; 370:fnad049. [PMID: 37291701 PMCID: PMC10732223 DOI: 10.1093/femsle/fnad049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 06/02/2023] [Accepted: 06/07/2023] [Indexed: 06/10/2023] Open
Abstract
The Oslofjord subsea road tunnel is a unique environment in which the typically anoxic marine deep subsurface is exposed to oxygen. Concrete biodeterioration and steel corrosion in the tunnel have been linked to the growth of iron- and manganese-oxidizing biofilms in areas of saline water seepage. Surprisingly, previous 16S rRNA gene surveys of biofilm samples revealed microbial communities dominated by sequences affiliated with nitrogen-cycling microorganisms. This study aimed to identify microbial genomes with metabolic potential for novel nitrogen- and metal-cycling reactions, representing biofilm microorganisms that could link these cycles and play a role in concrete biodeterioration. We reconstructed 33 abundant, novel metagenome-assembled genomes (MAGs) affiliated with the phylum Planctomycetota and the candidate phylum KSB1. We identified novel and unusual genes and gene clusters in these MAGs related to anaerobic ammonium oxidation, nitrite oxidation, and other nitrogen-cycling reactions. Additionally, 26 of 33 MAGs also had the potential for iron, manganese, and arsenite cycling, suggesting that bacteria represented by these genomes might couple these reactions. Our results expand the diversity of microorganisms putatively involved in nitrogen and metal cycling, and contribute to our understanding of potential biofilm impacts on built infrastructure.
Collapse
Affiliation(s)
- Carolina Suarez
- Division of Water Resources Engineering, Faculty of Engineering LTH, Lund University, Lund 221 00, Sweden
| | - Thomas Hackl
- Microbial Ecology Cluster, GELIFES, University of Groningen, Groningen 9747 AG, Netherlands
| | - Britt-Marie Wilen
- Division of Water Environment Technology, Department of Architecture and Civil Engineering, Chalmers University of Technology, Gothenburg 412 96, Sweden
| | - Frank Persson
- Division of Water Environment Technology, Department of Architecture and Civil Engineering, Chalmers University of Technology, Gothenburg 412 96, Sweden
| | - Per Hagelia
- Construction Division, The Norwegian Public Roads, Administration, Oslo 0667, Norway
| | - Mike S M Jetten
- Department of Microbiology, RIBES, Radboud University, Nijmegen 6525 AJ, Netherlands
| | - Paula Dalcin Martins
- Microbial Ecology Cluster, GELIFES, University of Groningen, Groningen 9747 AG, Netherlands
| |
Collapse
|
14
|
Cooper RE, Finck J, Chan C, Küsel K. Mixotrophy broadens the ecological niche range of the iron oxidizer Sideroxydans sp. CL21 isolated from an iron-rich peatland. FEMS Microbiol Ecol 2023; 99:6979798. [PMID: 36623865 PMCID: PMC9925335 DOI: 10.1093/femsec/fiac156] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/17/2022] [Accepted: 01/06/2023] [Indexed: 01/11/2023] Open
Abstract
Sideroxydans sp. CL21 is a microaerobic, acid-tolerant Fe(II)-oxidizer, isolated from the Schlöppnerbrunnen fen. Since the genome size of Sideroxydans sp. CL21 is 21% larger than that of the neutrophilic Sideroxydans lithotrophicus ES-1, we hypothesized that strain CL21 contains additional metabolic traits to thrive in the fen. The common genomic content of both strains contains homologs of the putative Fe(II) oxidation genes, mtoAB and cyc2. A large part of the accessory genome in strain CL21 contains genes linked to utilization of alternative electron donors, including NiFe uptake hydrogenases, and genes encoding lactate uptake and utilization proteins, motility and biofilm formation, transposable elements, and pH homeostasis mechanisms. Next, we incubated the strain in different combinations of electron donors and characterized the fen microbial communities. Sideroxydans spp. comprised 3.33% and 3.94% of the total relative abundance in the peatland soil and peatland water, respectively. Incubation results indicate Sideroxydans sp. CL21 uses H2 and thiosulfate, while lactate only enhances growth when combined with Fe, H2, or thiosulfate. Rates of H2 utilization were highest in combination with other substrates. Thus, Sideroxydans sp. CL21 is a mixotroph, growing best by simultaneously using substrate combinations, which helps to thrive in dynamic and complex habitats.
Collapse
Affiliation(s)
- Rebecca E Cooper
- Aquatic Geomicrobiology, Institute of Biodiversity, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Jessica Finck
- Aquatic Geomicrobiology, Institute of Biodiversity, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Clara Chan
- School of Marine Science and Policy, University of Delaware, Newark, DE 19716, United States,Delaware Biotechnology Institute, University of Delaware, Newark, DE 19713, United States,Department of Earth Sciences, University of Delaware, Newark, DE 19716, United States
| | - Kirsten Küsel
- Corresponding author. Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Str. 159, 07743 Jena, Germany. Tel: +49 3641 949461; Fax: +49 3641 949462; E-mail:
| |
Collapse
|
15
|
Zhong YW, Zhou P, Cheng H, Zhou YD, Pan J, Xu L, Li M, Tao CH, Wu YH, Xu XW. Metagenomic Features Characterized with Microbial Iron Oxidoreduction and Mineral Interaction in Southwest Indian Ridge. Microbiol Spectr 2022; 10:e0061422. [PMID: 36286994 PMCID: PMC9769843 DOI: 10.1128/spectrum.00614-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 07/25/2022] [Indexed: 01/05/2023] Open
Abstract
The Southwest Indian Ridge (SWIR) is one of the typical representatives of deep-sea ultraslow-spreading ridges, and has increasingly become a hot spot of studying subsurface geological activities and deep-sea mining management. However, the understanding of microbial activities is still limited on active hydrothermal vent chimneys in SWIR. In this study, samples from an active black smoker and a diffuse vent located in the Longqi hydrothermal region were collected for deep metagenomic sequencing, which yielded approximately 290 GB clean data and 295 mid-to-high-quality metagenome-assembled genomes (MAGs). Sulfur oxidation conducted by a variety of Gammaproteobacteria, Alphaproteobacteria, and Campylobacterota was presumed to be the major energy source for chemosynthesis in Longqi hydrothermal vents. Diverse iron-related microorganisms were recovered, including iron-oxidizing Zetaproteobacteria, iron-reducing Deferrisoma, and magnetotactic bacterium. Twenty-two bacterial MAGs from 12 uncultured phyla harbored iron oxidase Cyc2 homologs and enzymes for organic carbon degradation, indicated novel chemolithoheterotrophic iron-oxidizing bacteria that affected iron biogeochemistry in hydrothermal vents. Meanwhile, potential interactions between microbial communities and chimney minerals were emphasized as enriched metabolic potential of siderophore transportation, and extracellular electron transfer functioned by multi-heme proteins was discovered. Composition of chimney minerals probably affected microbial iron metabolic potential, as pyrrhotite might provide more available iron for microbial communities. Collectively, this study provides novel insights into microbial activities and potential mineral-microorganism interactions in hydrothermal vents. IMPORTANCE Microbial activities and interactions with minerals and venting fluid in active hydrothermal vents remain unclear in the ultraslow-spreading SWIR (Southwest Indian Ridge). Understanding about how minerals influence microbial metabolism is currently limited given the obstacles in cultivating microorganisms with sulfur or iron oxidoreduction functions. Here, comprehensive descriptions on microbial composition and metabolic profile on 2 hydrothermal vents in SWIR were obtained based on cultivation-free metagenome sequencing. In particular, autotrophic sulfur oxidation supported by minerals was presumed, emphasizing the role of chimney minerals in supporting chemosynthesis. Presence of novel heterotrophic iron-oxidizing bacteria was also indicated, suggesting overlooked biogeochemical pathways directed by microorganisms that connected sulfide mineral dissolution and organic carbon degradation in hydrothermal vents. Our findings offer novel insights into microbial function and biotic interactions on minerals in ultraslow-spreading ridges.
Collapse
Affiliation(s)
- Ying-Wen Zhong
- School of Oceanography, Shanghai Jiao Tong University, Shanghai, PR China
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources & Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, PR China
| | - Peng Zhou
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources & Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, PR China
| | - Hong Cheng
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources & Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, PR China
| | - Ya-Dong Zhou
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources & Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, PR China
| | - Jie Pan
- Archaeal Biology Center, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, PR China
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, PR China
| | - Lin Xu
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources & Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, PR China
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, PR China
| | - Meng Li
- Archaeal Biology Center, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, PR China
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, PR China
| | - Chun-Hui Tao
- School of Oceanography, Shanghai Jiao Tong University, Shanghai, PR China
- Key Laboratory of Submarine Geosciences, Ministry of Natural Resources & Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, PR China
| | - Yue-Hong Wu
- School of Oceanography, Shanghai Jiao Tong University, Shanghai, PR China
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources & Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, PR China
| | - Xue-Wei Xu
- School of Oceanography, Shanghai Jiao Tong University, Shanghai, PR China
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources & Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, PR China
| |
Collapse
|
16
|
Chen Y, Li X, Liu T, Li F, Sun W, Young LY, Huang W. Metagenomic analysis of Fe(II)-oxidizing bacteria for Fe(III) mineral formation and carbon assimilation under microoxic conditions in paddy soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 851:158068. [PMID: 35987227 DOI: 10.1016/j.scitotenv.2022.158068] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 08/08/2022] [Accepted: 08/12/2022] [Indexed: 06/15/2023]
Abstract
Microbially mediated Fe(II) oxidation is prevalent and thought to be central to many biogeochemical processes in paddy soils. However, we have limited insights into the Fe(II) oxidation process in paddy fields, considered the world's largest engineered wetland, where microoxic conditions are ubiquitous. In this study, microaerophilic Fe(II) oxidizing bacteria (FeOB) from paddy soil were enriched in gradient tubes with FeS, FeCO3, and Fe3(PO4)2 as iron sources to investigate their capacity for Fe(II) oxidation and carbon assimilation. Results showed that the highest rate of Fe(II) oxidation (k = 0.836 mM d-1) was obtained in the FeCO3 tubes, and cells grown in the Fe3(PO4)2 tubes yielded maximum assimilation amounts of 13C-NaHCO3 of 1.74% on Day 15. Amorphous Fe(III) oxides were found in all the cell bands with iron substrates as a result of microbial Fe(II) oxidation. Metagenomics analysis of the enriched microbes targeted genes encoding iron oxidase Cyc2, oxygen-reducing terminal oxidase, and ribulose-bisphosphate carboxylase, with results indicated that the potential Fe(II) oxidizers include nitrate-reducing FeOB (Dechloromonas and Thiobacillus), Curvibacter, and Magnetospirillum. By combining cultivation-dependent and metagenomic approaches, our results found a number of FeOB from paddy soil under microoxic conditions, which provide insight into the complex biogeochemical interactions of iron and carbon within paddy fields. The contribution of the FeOB to the element cycling in rice-growing regions deserves further investigation.
Collapse
Affiliation(s)
- Yating Chen
- Institute for Disaster Management and Reconstruction, Sichuan University-Hong Kong Polytechnic University, Chengdu 610207, China
| | - Xiaomin Li
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China.
| | - Tongxu Liu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Fangbai Li
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China.
| | - Weimin Sun
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Lily Y Young
- Department of Environmental Sciences, Rutgers University, New Brunswick, NJ 08901, USA
| | - Weilin Huang
- Department of Environmental Sciences, Rutgers University, New Brunswick, NJ 08901, USA
| |
Collapse
|
17
|
Zhou N, Kupper RJ, Catalano JG, Thompson A, Chan CS. Biological Oxidation of Fe(II)-Bearing Smectite by Microaerophilic Iron Oxidizer Sideroxydans lithotrophicus Using Dual Mto and Cyc2 Iron Oxidation Pathways. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:17443-17453. [PMID: 36417801 PMCID: PMC9731265 DOI: 10.1021/acs.est.2c05142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 10/03/2022] [Accepted: 10/24/2022] [Indexed: 06/16/2023]
Abstract
Fe(II) clays are common across many environments, making them a potentially significant microbial substrate, yet clays are not well established as an electron donor. Therefore, we explored whether Fe(II)-smectite supports the growth of Sideroxydans lithotrophicus ES-1, a microaerophilic Fe(II)-oxidizing bacterium (FeOB), using synthesized trioctahedral Fe(II)-smectite and 2% oxygen. S. lithotrophicus grew substantially and can oxidize Fe(II)-smectite to a higher extent than abiotic oxidation, based on X-ray near-edge spectroscopy (XANES). Sequential extraction showed that edge-Fe(II) is oxidized before interior-Fe(II) in both biotic and abiotic experiments. The resulting Fe(III) remains in smectite, as secondary minerals were not detected in biotic and abiotic oxidation products by XANES and Mössbauer spectroscopy. To determine the genes involved, we compared S. lithotrophicus grown on smectite versus Fe(II)-citrate using reverse-transcription quantitative PCR and found that cyc2 genes were highly expressed on both substrates, while mtoA was upregulated on smectite. Proteomics confirmed that Mto proteins were only expressed on smectite, indicating that ES-1 uses the Mto pathway to access solid Fe(II). We integrate our results into a biochemical and mineralogical model of microbial smectite oxidation. This work increases the known substrates for FeOB growth and expands the mechanisms of Fe(II)-smectite alteration in the environment.
Collapse
Affiliation(s)
- Nanqing Zhou
- School
of Marine Science and Policy, University
of Delaware, Newark, Delaware 19716, United
States
| | - Robert J. Kupper
- Department
of Earth and Planetary Sciences, Washington
University in St. Louis, Saint
Louis, Missouri 63130, United States
| | - Jeffrey G. Catalano
- Department
of Earth and Planetary Sciences, Washington
University in St. Louis, Saint
Louis, Missouri 63130, United States
| | - Aaron Thompson
- Department
of Crop and Soil Sciences, University of
Georgia, Athens, Georgia 30602, United States
| | - Clara S. Chan
- School
of Marine Science and Policy, University
of Delaware, Newark, Delaware 19716, United
States
- Department
of Earth Sciences, University of Delaware, Newark, Delaware 19716, United States
| |
Collapse
|
18
|
Kato S, Masuda S, Shibata A, Shirasu K, Ohkuma M. Insights into ecological roles of uncultivated bacteria in Katase hot spring sediment from long-read metagenomics. Front Microbiol 2022; 13:1045931. [PMID: 36406403 PMCID: PMC9671151 DOI: 10.3389/fmicb.2022.1045931] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 10/11/2022] [Indexed: 08/11/2023] Open
Abstract
Diverse yet-uncultivated bacteria and archaea, i.e., microbial dark matter, are present in terrestrial hot spring environments. Numerous metagenome-assembled genomes (MAGs) of these uncultivated prokaryotes by short-read metagenomics have been reported so far, suggesting their metabolic potential. However, more reliable MAGs, i.e., circularized complete MAGs (cMAGs), have been rarely reported from hot spring environments. Here, we report 61 high-quality (HQ)-MAGs, including 14 cMAGs, of diverse uncultivated bacteria and archaea retrieved from hot spring sediment (52°C, pH 7.2) by highly accurate long-read sequencing using PacBio Sequel II. The HQ MAGs were affiliated with one archaeal and 13 bacterial phyla. Notably, nine of the 14 cMAGs were the first reported cMAGs for the family- to class-level clades that these cMAGs belonged to. The genome information suggests that the bacteria represented by MAGs play a significant role in the biogeochemical cycling of carbon, nitrogen, iron, and sulfur at this site. In particular, the genome analysis of six HQ MAGs including two cMAGs of Armatimonadota, of which members are frequently abundant in hot spring environments, predicts that they are aerobic, moderate thermophilic chemoorganoheterotrophs, and potentially oxidize and/or reduce iron. This prediction is consistent with the environmental conditions where they were detected. Our results expand the knowledge regarding the ecological potential of uncultivated bacteria in moderately-high-temperature environments.
Collapse
Affiliation(s)
- Shingo Kato
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, Japan
| | - Sachiko Masuda
- Plant Immunity Research Group, RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Arisa Shibata
- Plant Immunity Research Group, RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Ken Shirasu
- Plant Immunity Research Group, RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Moriya Ohkuma
- Japan Collection of Microorganisms, RIKEN BioResource Research Center, Tsukuba, Japan
| |
Collapse
|
19
|
Conservation of Energetic Pathways for Electroautotrophy in the Uncultivated Candidate Order Tenderiales. mSphere 2022; 7:e0022322. [PMID: 36069437 PMCID: PMC9599434 DOI: 10.1128/msphere.00223-22] [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] [Indexed: 11/20/2022] Open
Abstract
Electromicrobiology can be used to understand extracellular electron uptake in previously undescribed chemolithotrophs. Enrichment and characterization of the uncultivated electroautotroph "Candidatus Tenderia electrophaga" using electromicrobiology led to the designation of the order Tenderiales. Representative Tenderiales metagenome-assembled genomes (MAGs) have been identified in a number of environmental surveys, yet a comprehensive characterization of conserved genes for extracellular electron uptake has thus far not been conducted. Using comparative genomics, we identified conserved orthologous genes within the Tenderiales and nearest-neighbor orders important for extracellular electron uptake based on a previously proposed pathway from "Ca. Tenderia electrophaga." The Tenderiales contained a conserved cluster we designated uetABCDEFGHIJ, which encodes proteins containing features that would enable transport of extracellular electrons to cytoplasmic membrane-bound energy-transducing complexes such as two conserved cytochrome cbb3 oxidases. For example, UetJ is predicted to be an extracellular undecaheme c-type cytochrome that forms a heme wire. We also identified clusters of genes predicted to facilitate assembly and maturation of electron transport proteins, as well as cellular attachment to surfaces. Autotrophy among the Tenderiales is supported by the presence of carbon fixation and stress response pathways that could allow cellular growth by extracellular electron uptake. Key differences between the Tenderiales and other known neutrophilic iron oxidizers were revealed, including very few Cyc2 genes in the Tenderiales. Our results reveal a possible conserved pathway for extracellular electron uptake and suggest that the Tenderiales have an ecological role in coupling metal or mineral redox chemistry and the carbon cycle in marine and brackish sediments. IMPORTANCE Chemolithotrophic bacteria capable of extracellular electron uptake to drive energy metabolism and CO2 fixation are known as electroautotrophs. The recently described order Tenderiales contains the uncultivated electroautotroph "Ca. Tenderia electrophaga." The "Ca. Tenderia electrophaga" genome contains genes proposed to make up a previously undescribed extracellular electron uptake pathway. Here, we use comparative genomics to show that this pathway is well conserved among Tenderiales spp. recovered by metagenome-assembled genomes. This conservation extends to near neighbors of the Tenderiales but not to other well-studied chemolithotrophs, including iron and sulfur oxidizers, indicating that these genes may be useful markers of growth using insoluble extracellular electron donors. Our findings suggest that extracellular electron uptake and electroautotrophy may be pervasive among the Tenderiales, and the geographic locations from which metagenome-assembled genomes were recovered offer clues to their natural ecological niche.
Collapse
|
20
|
Ciancio Casalini L, Piazza A, Masotti F, Garavaglia BS, Ottado J, Gottig N. Manganese oxidation counteracts the deleterious effect of low temperatures on biofilm formation in Pseudomonas sp. MOB-449. Front Mol Biosci 2022; 9:1015582. [DOI: 10.3389/fmolb.2022.1015582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 10/10/2022] [Indexed: 11/13/2022] Open
Abstract
Mn removal from groundwater by biological sand filter technology is negatively impacted by low temperatures in winter periods. Therefore, the need to study Mn(II)-oxidizing bacteria (MOB) having the potential to oxidize Mn(II) and form biofilms at low temperatures is imperative. These MOB can have potential as inocula for sand filter bioaugmentation strategies to optimize Mn removal during winter periods. We previously showed that a Pseudomonas sp. MOB-449 (MOB-449), isolated from a Mn biofilter, oxidizes Mn(II) in a biofilm-dependent way at low temperatures. In this work, MOB-449 Mn(II) oxidation and growth capacities were evaluated under planktonic and biofilm conditions at different temperatures. At 18°C, MOB-449 showed enhanced biofilm formation due to the addition of Mn(II) to the medium correlating with Mn(II) oxidation, compared to biofilms grown in control medium. Moreover, this enhancement on biofilm formation due to the addition of Mn(II) was only observed at 18°C. At this temperature, Mn(II) oxidation in membrane fractions collected from biofilms was induced by uncoupling oxidative phosphorylation from the electron transport chain with 2,4-Dinitrophenol. In Pseudomonas, a role for c-type cytochrome in Mn(II) oxidation has been demonstrated. Accordingly, transcriptional profiles of all terminal oxidases genes found in MOB-449 showed an induction of cytochrome c terminal oxidases expression mediated by Mn(II) oxidation at 18°C. Finally, heme peroxidase activity assays and MS analysis revealed that PetC, a cytochrome c5, and also CcmE, involved in the cytochrome c biogenesis machinery, are induced at 18°C only in the presence of Mn(II). These results present evidence supporting that cytochromes c and also the cytochrome c terminal oxidases are activated at low temperatures in the presence of Mn(II). Overall, this work demonstrate that in MOB-449 Mn(II) oxidation is activated at low temperatures to gain energy, suggesting that this process is important for survival under adverse environmental conditions and contributing to the understanding of the physiological role of bacterial Mn(II) oxidation.
Collapse
|
21
|
Liu K, Schiff SL, Wu L, Molot LA, Venkiteswaran JJ, Paterson MJ, Elgood RJ, Tsuji JM, Neufeld JD. Large Fractionation in Iron Isotopes Implicates Metabolic Pathways for Iron Cycling in Boreal Shield Lakes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:14840-14851. [PMID: 36162065 DOI: 10.1021/acs.est.2c04247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Stable Fe isotopes have only recently been measured in freshwater systems, mainly in meromictic lakes. Here we report the δ56Fe of dissolved, particulate, and sediment Fe in two small dimictic boreal shield headwater lakes: manipulated eutrophic Lake 227, with annual cyanobacterial blooms, and unmanipulated oligotrophic Lake 442. Within the lakes, the range in δ56Fe is large (ca. -0.9 to +1.8‰), spanning more than half the entire range of natural Earth surface samples. Two layers in the water column with distinctive δ56Fe of dissolved (dis) and particulate (spm) Fe were observed, despite differences in trophic states. In the epilimnia of both lakes, a large Δ56Fedis-spm fractionation of 0.4-1‰ between dissolved and particulate Fe was only observed during cyanobacterial blooms in Lake 227, possibly regulated by selective biological uptake of isotopically light Fe by cyanobacteria. In the anoxic layers in both lakes, upward flux from sediments dominates the dissolved Fe pool with an apparent Δ56Fedis-spm fractionation of -2.2 to -0.6‰. Large Δ56Fedis-spm and previously published metagenome sequence data suggest active Fe cycling processes in anoxic layers, such as microaerophilic Fe(II) oxidation or photoferrotrophy, could regulate biogeochemical cycling. Large fractionation of stable Fe isotopes in these lakes provides a potential tool to probe Fe cycling and the acquisition of Fe by cyanobacteria, with relevance for understanding biogeochemical cycling of Earth's early ferruginous oceans.
Collapse
Affiliation(s)
- Kai Liu
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- Water Institute, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Sherry L Schiff
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- Water Institute, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Lingling Wu
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- Water Institute, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Lewis A Molot
- Faculty of Environmental and Urban Change, York University, Toronto, Ontario M3J 1P3, Canada
| | - Jason J Venkiteswaran
- Department of Geography and Environmental Studies, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5, Canada
| | | | - Richard J Elgood
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- Water Institute, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Jackson M Tsuji
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Josh D Neufeld
- Water Institute, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| |
Collapse
|
22
|
Wei M, Zeng X, Han X, Shao Z, Xie Q, Dong C, Wang Y, Qiu Z. Potential autotrophic carbon-fixer and Fe(II)-oxidizer Alcanivorax sp. MM125-6 isolated from Wocan hydrothermal field. Front Microbiol 2022; 13:930601. [PMID: 36316996 PMCID: PMC9616709 DOI: 10.3389/fmicb.2022.930601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 09/09/2022] [Indexed: 12/02/2022] Open
Abstract
The genus Alcanivorax is common in various marine environments, including in hydrothermal fields. They were previously recognized as obligate hydrocarbonoclastic bacteria, but their potential for autotrophic carbon fixation and Fe(II)-oxidation remains largely elusive. In this study, an in situ enrichment experiment was performed using a hydrothermal massive sulfide slab deployed 300 m away from the Wocan hydrothermal vent. Furthermore, the biofilms on the surface of the slab were used as an inoculum, with hydrothermal massive sulfide powder from the same vent as an energy source, to enrich the potential iron oxidizer in the laboratory. Three dominant bacterial families, Alcanivoraceae, Pseudomonadaceae, and Rhizobiaceae, were enriched in the medium with hydrothermal massive sulfides. Subsequently, strain Alcanivorax sp. MM125-6 was isolated from the enrichment culture. It belongs to the genus Alcanivorax and is closely related to Alcanivorax profundimaris ST75FaO-1T (98.9% sequence similarity) indicated by a phylogenetic analysis based on 16S rRNA gene sequences. Autotrophic growth experiments on strain MM125-6 revealed that the cell concentrations were increased from an initial 7.5 × 105 cells/ml to 3.13 × 108 cells/ml after 10 days, and that the δ13CVPDB in the cell biomass was also increased from 234.25‰ on day 2 to gradually 345.66 ‰ on day 10. The gradient tube incubation showed that bands of iron oxides and cells formed approximately 1 and 1.5 cm, respectively, below the air-agarose medium interface. In addition, the SEM-EDS data demonstrated that it can also secrete acidic exopolysaccharides and adhere to the surface of sulfide minerals to oxidize Fe(II) with NaHCO3 as the sole carbon source, which accelerates hydrothermal massive sulfide dissolution. These results support the conclusion that strain MM125-6 is capable of autotrophic carbon fixation and Fe(II) oxidization chemoautotrophically. This study expands our understanding of the metabolic versatility of the Alcanivorax genus as well as their important role(s) in coupling hydrothermal massive sulfide weathering and iron and carbon cycles in hydrothermal fields.
Collapse
Affiliation(s)
- Mingcong Wei
- Ocean College, Zhejiang University, Zhoushan, China
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
| | - Xiang Zeng
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Xiqiu Han
- Ocean College, Zhejiang University, Zhoushan, China
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
- *Correspondence: Xiqiu Han,
| | - Zongze Shao
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Qian Xie
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
- School of Oceanography, Shanghai Jiao Tong University, Shanghai, China
| | - Chuanqi Dong
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
- College of Marine Geosciences, Ocean University of China, Qingdao, China
| | - Yejian Wang
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
| | - Zhongyan Qiu
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
| |
Collapse
|
23
|
Ward LM, Shih PM. Phototrophy and carbon fixation in Chlorobi postdate the rise of oxygen. PLoS One 2022; 17:e0270187. [PMID: 35913911 PMCID: PMC9342728 DOI: 10.1371/journal.pone.0270187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 06/07/2022] [Indexed: 11/28/2022] Open
Abstract
While most productivity on the surface of the Earth today is fueled by oxygenic photosynthesis, for much of Earth history it is thought that anoxygenic photosynthesis-using compounds like ferrous iron or sulfide as electron donors-drove most global carbon fixation. Anoxygenic photosynthesis is still performed by diverse bacteria in niche environments today. Of these, the Chlorobi (formerly green sulfur bacteria) are often interpreted as being particularly ancient and are frequently proposed to have fueled the biosphere during late Archean and early Paleoproterozoic time before the rise of oxygenic photosynthesis. Here, we perform comparative genomic, phylogenetic, and molecular clock analyses to determine the antiquity of the Chlorobi and their characteristic phenotypes. We show that contrary to common assumptions, the Chlorobi clade is relatively young, with anoxygenic phototrophy, carbon fixation via the rTCA pathway, and iron oxidation all significantly postdating the rise of oxygen ~2.3 billion years ago. The Chlorobi therefore could not have fueled the Archean biosphere, but instead represent a relatively young radiation of organisms which likely acquired the capacity for anoxygenic photosynthesis and other traits via horizontal gene transfer sometime after the evolution of oxygenic Cyanobacteria.
Collapse
Affiliation(s)
- L. M. Ward
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts, United States of America
- Department of Geosciences, Smith College, Northampton, Massachusetts, United States of America
| | - Patrick M. Shih
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, United States of America
- Feedstocks Division, Joint BioEnergy Institute, Emeryville, California, United States of America
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, California, United States of America
| |
Collapse
|
24
|
Zhong YW, Zhou P, Cheng H, Xu XW, Wu YH. Genome sequence of five Zetaproteobacteria metagenome-assembled genomes recovered from hydrothermal vent Longqi, Southwest Indian Ridge. Mar Genomics 2022; 63:100936. [DOI: 10.1016/j.margen.2022.100936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/15/2022] [Accepted: 02/15/2022] [Indexed: 11/15/2022]
|
25
|
Dede B, Hansen CT, Neuholz R, Schnetger B, Kleint C, Walker S, Bach W, Amann R, Meyerdierks A. Niche differentiation of sulfur-oxidizing bacteria (SUP05) in submarine hydrothermal plumes. THE ISME JOURNAL 2022; 16:1479-1490. [PMID: 35082431 PMCID: PMC9123188 DOI: 10.1038/s41396-022-01195-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 01/03/2022] [Accepted: 01/10/2022] [Indexed: 11/09/2022]
Abstract
Hydrothermal plumes transport reduced chemical species and metals into the open ocean. Despite their considerable spatial scale and impact on biogeochemical cycles, niche differentiation of abundant microbial clades is poorly understood. Here, we analyzed the microbial ecology of two bathy- (Brothers volcano; BrV-cone and northwest caldera; NWC) and a mesopelagic (Macauley volcano; McV) plumes on the Kermadec intra-oceanic arc in the South Pacific Ocean. The microbial community structure, determined by a combination of 16S rRNA gene, fluorescence in situ hybridization and metagenome analysis, was similar to the communities observed in other sulfur-rich plumes. This includes a dominance of the vent characteristic SUP05 clade (up to 22% in McV and 51% in BrV). In each of the three plumes analyzed, the community was dominated by a different yet uncultivated chemoautotrophic SUP05 species, here, provisionally named, Candidatus Thioglobus vadi (McV), Candidatus Thioglobus vulcanius (BrV-cone) and Candidatus Thioglobus plumae (BrV-NWC). Statistical analyses, genomic potential and mRNA expression profiles suggested a SUP05 niche partitioning based on sulfide and iron concentration as well as water depth. A fourth SUP05 species was present at low frequency throughout investigated plume samples and may be capable of heterotrophic or mixotrophic growth. Taken together, we propose that small variations in environmental parameters and depth drive SUP05 niche partitioning in hydrothermal plumes.
Collapse
Affiliation(s)
- Bledina Dede
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Christian T Hansen
- MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Rene Neuholz
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
- Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM), Group: Quality Assurance and Cyber-Physical Systems, Bremen, Germany
| | - Bernhard Schnetger
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Charlotte Kleint
- MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
- Department of Physics and Earth Sciences, Jacobs University Bremen, Bremen, Germany
| | - Sharon Walker
- National Oceanic and Atmospheric Administration, Pacific Marine Environmental Laboratory, Seattle, WA, USA
| | - Wolfgang Bach
- MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
- Geoscience Department, University of Bremen, Bremen, Germany
| | - Rudolf Amann
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | | |
Collapse
|
26
|
Napieralski SA, Fang Y, Marcon V, Forsythe B, Brantley SL, Xu H, Roden EE. Microbial chemolithotrophic oxidation of pyrite in a subsurface shale weathering environment: Geologic considerations and potential mechanisms. GEOBIOLOGY 2022; 20:271-291. [PMID: 34633148 DOI: 10.1111/gbi.12474] [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: 02/18/2021] [Revised: 09/02/2021] [Accepted: 09/27/2021] [Indexed: 06/13/2023]
Abstract
Oxidative weathering of pyrite plays an important role in the biogeochemical cycling of Fe and S in terrestrial environments. While the mechanism and occurrence of biologically accelerated pyrite oxidation under acidic conditions are well established, much less is known about microbially mediated pyrite oxidation at circumneutral pH. Recent work (Percak-Dennett et al., 2017, Geobiology, 15, 690) has demonstrated the ability of aerobic chemolithotrophic microorganisms to accelerate pyrite oxidation at circumneutral pH and proposed two mechanistic models by which this phenomenon might occur. Here, we assess the potential relevance of aerobic microbially catalyzed circumneutral pH pyrite oxidation in relation to subsurface shale weathering at Susquehanna Shale Hills Critical Zone Observatory (SSHCZO) in Pennsylvania, USA. Specimen pyrite mixed with native shale was incubated in groundwater for 3 months at the inferred depth of in situ pyrite oxidation. The colonized materials were used as an inoculum for pyrite-oxidizing enrichment cultures. Microbial activity accelerated the release of sulfate across all conditions. 16S rRNA gene sequencing and metagenomic analysis revealed the dominance of a putative chemolithoautotrophic sulfur-oxidizing bacterium from the genus Thiobacillus in the enrichment cultures. Previously proposed models for aerobic microbial pyrite oxidation were assessed in terms of physical constraints, enrichment culture geochemistry, and metagenomic analysis. Although we conclude that subsurface pyrite oxidation at SSCHZO is largely abiotic, this work nonetheless yields new insight into the potential pathways by which aerobic microorganisms may accelerate pyrite oxidation at circumneutral pH. We propose a new "direct sulfur oxidation" pathway, whereby sulfhydryl-bearing outer membrane proteins mediate oxidation of pyrite surfaces through a persulfide intermediate, analogous to previously proposed mechanisms for direct microbial oxidation of elemental sulfur. The action of this and other direct microbial pyrite oxidation pathways have major implications for controls on pyrite weathering rates in circumneutral pH sedimentary environments where pore throat sizes permit widespread access of microorganisms to pyrite surfaces.
Collapse
Affiliation(s)
| | - Yihang Fang
- Department of Geoscience, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Virginia Marcon
- Earth and Environmental Systems Institute, University Park, Pennsylvania, USA
- The Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Brandon Forsythe
- Earth and Environmental Systems Institute, University Park, Pennsylvania, USA
| | - Susan L Brantley
- Earth and Environmental Systems Institute, University Park, Pennsylvania, USA
- The Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Huifang Xu
- Department of Geoscience, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Eric E Roden
- Department of Geoscience, University of Wisconsin-Madison, Madison, Wisconsin, USA
| |
Collapse
|
27
|
Bendia AG, Callefo F, Araújo MN, Sanchez E, Teixeira VC, Vasconcelos A, Battilani G, Pellizari VH, Rodrigues F, Galante D. Metagenome-Assembled Genomes from Monte Cristo Cave (Diamantina, Brazil) Reveal Prokaryotic Lineages As Functional Models for Life on Mars. ASTROBIOLOGY 2022; 22:293-312. [PMID: 34694925 DOI: 10.1089/ast.2021.0016] [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] [Indexed: 06/13/2023]
Abstract
Microbial communities have been explored in various terrestrial subsurface ecosystems, showing metabolic potentials that could generate noteworthy morphological and molecular biosignatures. Recent advancements in bioinformatic tools have allowed for descriptions of novel and yet-to-be cultivated microbial lineages in different ecosystems due to the genome reconstruction approach from metagenomic data. Using shotgun metagenomic data, we obtained metagenome-assembled genomes related to cultivated and yet-to-be cultivated prokaryotic lineages from a silica and iron-rich cave (Monte Cristo) in Minas Gerais State, Brazil. The Monte Cristo Cave has been shown to possess a high diversity of genes involved with different biogeochemical cycles, including reductive and oxidative pathways related to carbon, sulfur, nitrogen, and iron. Three genomes were selected for pangenomic analysis, assigned as Truepera sp., Ca. Methylomirabilis sp., and Ca. Koribacter sp. based on their lifestyles (radiation resistance, anaerobic methane oxidation, and potential iron oxidation). These bacteria exhibit genes involved with multiple DNA repair strategies, starvation, and stress response. Because these groups have few reference genomes deposited in databases, our study adds important genomic information about these lineages. The combination of techniques applied in this study allowed us to unveil the potential relationships between microbial genomes and their ecological processes with the cave mineralogy and highlight the lineages involved with anaerobic methane oxidation, iron oxidation, and radiation resistance as functional models for the search for extant life-forms outside our planet in silica- and iron-rich environments and potentially on Mars.
Collapse
Affiliation(s)
- Amanda G Bendia
- Biological Oceanography Department, Oceanographic Institute, Universidade de São Paulo, São Paulo, Brazil
| | - Flavia Callefo
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Maicon N Araújo
- Fundamental Chemistry Department, Institute of Chemistry, Universidade de São Paulo, São Paulo, Brazil
| | - Evelyn Sanchez
- Institute of Science and Technology, Federal University of the Jequitinhonha and Mucuri, Diamantina, Brazil
| | - Verônica C Teixeira
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Alessandra Vasconcelos
- Institute of Science and Technology, Federal University of the Jequitinhonha and Mucuri, Diamantina, Brazil
| | - Gislaine Battilani
- Institute of Science and Technology, Federal University of the Jequitinhonha and Mucuri, Diamantina, Brazil
| | - Vivian H Pellizari
- Biological Oceanography Department, Oceanographic Institute, Universidade de São Paulo, São Paulo, Brazil
| | - Fabio Rodrigues
- Fundamental Chemistry Department, Institute of Chemistry, Universidade de São Paulo, São Paulo, Brazil
| | - Douglas Galante
- Brazilian Synchrotron Light Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| |
Collapse
|
28
|
Lovley DR. Electrotrophy: Other microbial species, iron, and electrodes as electron donors for microbial respirations. BIORESOURCE TECHNOLOGY 2022; 345:126553. [PMID: 34906705 DOI: 10.1016/j.biortech.2021.126553] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/06/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
Electrotrophy, the growth of microbes on extracellular electron donors, drives important biogeochemical cycles and has practical applications. Studies of Fe(II)-based electrotrophy have provided foundational cytochrome-based mechanistic models for electron transport into cells. Direct electron uptake from other microbial species, Fe(0), or cathodes is of intense interest due to its potential roles in the production and anaerobic oxidation of methane, corrosion, and bioelectrochemical technologies. Other cells or Fe(0) can serve as the sole electron donor supporting the growth of several Geobacter and methanogen strains that are unable to use H2 as an electron donor, providing strong evidence for electrotrophy. Additional evidence for electrotrophy in Geobacter strains and Methanosarcina acetivorans is a requirement for outer-surface c-type cytochromes. However, in most instances claims for electrotrophy in anaerobes are based on indirect inference and the possibility that H2 is actually the electron donor supporting growth has not been rigorously excluded.
Collapse
Affiliation(s)
- Derek R Lovley
- Electrobiomaterials Institute, Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110819, China; Department of Microbiology and Institute for Applied Life Sciences (IALS), University of Massachusetts, Amherst, MA, USA.
| |
Collapse
|
29
|
Zhou N, Keffer JL, Polson SW, Chan CS. Unraveling Fe(II)-Oxidizing Mechanisms in a Facultative Fe(II) Oxidizer, Sideroxydans lithotrophicus Strain ES-1, via Culturing, Transcriptomics, and Reverse Transcription-Quantitative PCR. Appl Environ Microbiol 2022; 88:e0159521. [PMID: 34788064 PMCID: PMC8788666 DOI: 10.1128/aem.01595-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 11/11/2021] [Indexed: 11/20/2022] Open
Abstract
Sideroxydans lithotrophicus ES-1 grows autotrophically either by Fe(II) oxidation or by thiosulfate oxidation, in contrast to most other isolates of neutrophilic Fe(II)-oxidizing bacteria (FeOB). This provides a unique opportunity to explore the physiology of a facultative FeOB and constrain the genes specific to Fe(II) oxidation. We compared the growth of S. lithotrophicus ES-1 on Fe(II), thiosulfate, and both substrates together. While initial growth rates were similar, thiosulfate-grown cultures had higher yield with or without Fe(II) present, which may give ES-1 an advantage over obligate FeOB. To investigate the Fe(II) and S oxidation pathways, we conducted transcriptomics experiments, validated with reverse transcription-quantitative PCR (RT-qPCR). We explored the long-term gene expression response at different growth phases (over days to a week) and expression changes during a short-term switch from thiosulfate to Fe(II) (90 min). The dsr and sox sulfur oxidation genes were upregulated in thiosulfate cultures. The Fe(II) oxidase gene cyc2 was among the top expressed genes during both Fe(II) and thiosulfate oxidation, and addition of Fe(II) to thiosulfate-grown cells caused an increase in cyc2 expression. These results support the role of Cyc2 as the Fe(II) oxidase and suggest that ES-1 maintains readiness to oxidize Fe(II), even in the absence of Fe(II). We used gene expression profiles to further constrain the ES-1 Fe(II) oxidation pathway. Notably, among the most highly upregulated genes during Fe(II) oxidation were genes for alternative complex III, reverse electron transport, and carbon fixation. This implies a direct connection between Fe(II) oxidation and carbon fixation, suggesting that CO2 is an important electron sink for Fe(II) oxidation. IMPORTANCE Neutrophilic FeOB are increasingly observed in various environments, but knowledge of their ecophysiology and Fe(II) oxidation mechanisms is still relatively limited. Sideroxydans isolates are widely observed in aquifers, wetlands, and sediments, and genome analysis suggests metabolic flexibility contributes to their success. The type strain ES-1 is unusual among neutrophilic FeOB isolates, as it can grow on either Fe(II) or a non-Fe(II) substrate, thiosulfate. Almost all our knowledge of neutrophilic Fe(II) oxidation pathways comes from genome analyses, with some work on metatranscriptomes. This study used culture-based experiments to test the genes specific to Fe(II) oxidation in a facultative FeOB and refine our model of the Fe(II) oxidation pathway. We gained insight into how facultative FeOB like ES-1 connect Fe, S, and C biogeochemical cycling in the environment and suggest a multigene indicator would improve understanding of Fe(II) oxidation activity in environments with facultative FeOB.
Collapse
Affiliation(s)
- Nanqing Zhou
- School of Marine Science and Policy, University of Delaware, Newark, Delaware, USA
| | - Jessica L. Keffer
- Department of Earth Sciences, University of Delaware, Newark, Delaware, USA
| | - Shawn W. Polson
- Department of Computer and Information Sciences, University of Delaware, Newark, Delaware, USA
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, Delaware, USA
| | - Clara S. Chan
- School of Marine Science and Policy, University of Delaware, Newark, Delaware, USA
- Department of Earth Sciences, University of Delaware, Newark, Delaware, USA
| |
Collapse
|
30
|
D’Angelo T, Goordial J, Poulton NJ, Seyler L, Huber JA, Stepanauskas R, Orcutt BN. Oceanic Crustal Fluid Single Cell Genomics Complements Metagenomic and Metatranscriptomic Surveys With Orders of Magnitude Less Sample Volume. Front Microbiol 2022; 12:738231. [PMID: 35140689 PMCID: PMC8819061 DOI: 10.3389/fmicb.2021.738231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 11/30/2021] [Indexed: 12/22/2022] Open
Abstract
Fluids circulating through oceanic crust play important roles in global biogeochemical cycling mediated by their microbial inhabitants, but studying these sites is challenged by sampling logistics and low biomass. Borehole observatories installed at the North Pond study site on the western flank of the Mid-Atlantic Ridge have enabled investigation of the microbial biosphere in cold, oxygenated basaltic oceanic crust. Here we test a methodology that applies redox-sensitive fluorescent molecules for flow cytometric sorting of cells for single cell genomic sequencing from small volumes of low biomass (approximately 103 cells ml-1) crustal fluid. We compare the resulting genomic data to a recently published paired metagenomic and metatranscriptomic analysis from the same site. Even with low coverage genome sequencing, sorting cells from less than one milliliter of crustal fluid results in similar interpretation of dominant taxa and functional profiles as compared to 'omics analysis that typically filter orders of magnitude more fluid volume. The diverse community dominated by Gammaproteobacteria, Bacteroidetes, Desulfobacterota, Alphaproteobacteria, and Zetaproteobacteria, had evidence of autotrophy and heterotrophy, a variety of nitrogen and sulfur cycling metabolisms, and motility. Together, results indicate fluorescence activated cell sorting methodology is a powerful addition to the toolbox for the study of low biomass systems or at sites where only small sample volumes are available for analysis.
Collapse
Affiliation(s)
- Timothy D’Angelo
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United States
| | - Jacqueline Goordial
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United States
- School of Environmental Sciences, University of Guelph, Guelph, ON, Canada
| | - Nicole J. Poulton
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United States
| | - Lauren Seyler
- School of Natural Science and Mathematics, Stockton University, Galloway, NJ, United States
- Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Julie A. Huber
- Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | | | - Beth N. Orcutt
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United States
| |
Collapse
|
31
|
Garber AI, Ramírez GA, McAllister SM, Orsi W, D'Hondt S. Cryptic metabolisms in anoxic subseafloor sediment. ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:696-701. [PMID: 34184398 PMCID: PMC8518782 DOI: 10.1111/1758-2229.12983] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/06/2021] [Indexed: 06/13/2023]
Abstract
Microbial gene expression in anoxic subseafloor sediment was recently explored in the Baltic Sea and the Peru Margin. Our analysis of these data reveals diverse transcripts encoding proteins associated with neutralization of reactive oxygen species, including catalase, which may provide an in situ source of oxygen. We also detect transcripts associated with oxidation of iron and sulfur, and with reduction of arsenate, selenate and nitrate. Given limited input of electron acceptors from outside the system, these results suggest that the microbial communities use an unexpectedly diverse variety of electron acceptors. Products of water radiolysis and their interactions with sediment continuously provide diverse electron acceptors and hydrogen. Cryptic microbial utilization of these oxidized substrates and H2 may be an important mechanism for multi-million-year survival under the extreme energy limitation in subseafloor sediment.
Collapse
Affiliation(s)
| | - Gustavo A. Ramírez
- Graduate School of Oceanography, University of Rhode IslandNarragansettRIUSA
- Department of Marine Sciences, University of North CarolinaChapel HillNCUSA
- College of Veterinary Medicine, Western University of Health SciencesPomonaCAUSA
| | - Sean M. McAllister
- Joint Institute for the Study of the Atmosphere and Ocean, University of WashingtonSeattleWAUSA
- Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric AdministrationSeattleWAUSA
| | - William Orsi
- Department of Earth & Environmental Sciences, Paleontology and GeobiologyLudwig‐Maximilians‐Universität MünchenMunich80333Germany
| | - Steven D'Hondt
- Graduate School of Oceanography, University of Rhode IslandNarragansettRIUSA
| |
Collapse
|
32
|
Casar CP, Momper LM, Kruger BR, Osburn MR. Iron-Fueled Life in the Continental Subsurface: Deep Mine Microbial Observatory, South Dakota, USA. Appl Environ Microbiol 2021; 87:e0083221. [PMID: 34378953 PMCID: PMC8478452 DOI: 10.1128/aem.00832-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 07/29/2021] [Indexed: 11/20/2022] Open
Abstract
Iron-bearing minerals are key components of the Earth's crust and potentially critical energy sources for subsurface microbial life. The Deep Mine Microbial Observatory (DeMMO) is situated in a range of iron-rich lithologies, and fracture fluids here reach concentrations as high as 8.84 mg/liter. Iron cycling is likely an important process, given the high concentrations of iron in fracture fluids and detection of putative iron-cycling taxa via marker gene surveys. However, a previous metagenomic survey detected no iron cycling potential at two DeMMO localities. Here, we revisited the potential for iron cycling at DeMMO using a new metagenomic data set including all DeMMO sites and FeGenie, a new annotation pipeline that is optimized for the detection of iron cycling genes. We annotated functional genes from whole metagenomic assemblies and metagenome-assembled genomes and characterized putative iron cycling pathways and taxa in the context of local geochemical conditions and available metabolic energy estimated from thermodynamic models. We reannotated previous metagenomic data, revealing iron cycling potential that was previously missed. Across both metagenomic data sets, we found that not only is there genetic potential for iron cycling at DeMMO, but also, iron is likely an important source of energy across the system. In response to the dramatic differences we observed between annotation approaches, we recommend the use of optimized pipelines where the detection of iron cycling genes is a major goal. IMPORTANCE We investigated iron cycling potential among microbial communities inhabiting iron-rich fracture fluids to a depth of 1.5 km in the continental crust. A previous study found no iron cycling potential in the communities despite the iron-rich nature of the system. A new tool for detecting iron cycling genes was recently published, which we used on a new data set. We combined this with a number of other approaches to get a holistic view of metabolic strategies across the communities, revealing iron cycling to be an important process here. In addition, we used the tool on the data from the previous study, revealing previously missed iron cycling potential. Iron is common in continental crust; thus, our findings are likely not unique to our study site. Our new view of important metabolic strategies underscores the importance of choosing optimized tools for detecting the potential for metabolisms like iron cycling that may otherwise be missed.
Collapse
Affiliation(s)
- C. P. Casar
- Department of Earth and Planetary Sciences, Northwestern University, Evanston, Illinois, USA
| | - L. M. Momper
- Earth and Environmental Sciences Practice, Exponent, Inc., Pasadena, California, USA
| | - B. R. Kruger
- Division of Hydrologic Sciences, Desert Research Institute, Las Vegas, Nevada, USA
| | - M. R. Osburn
- Department of Earth and Planetary Sciences, Northwestern University, Evanston, Illinois, USA
| |
Collapse
|
33
|
Garber AI, Cohen AB, Nealson KH, Ramírez GA, Barco RA, Enzingmüller-Bleyl TC, Gehringer MM, Merino N. Metagenomic Insights Into the Microbial Iron Cycle of Subseafloor Habitats. Front Microbiol 2021; 12:667944. [PMID: 34539592 PMCID: PMC8446621 DOI: 10.3389/fmicb.2021.667944] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 07/30/2021] [Indexed: 11/13/2022] Open
Abstract
Microbial iron cycling influences the flux of major nutrients in the environment (e.g., through the adsorptive capacity of iron oxides) and includes biotically induced iron oxidation and reduction processes. The ecological extent of microbial iron cycling is not well understood, even with increased sequencing efforts, in part due to limitations in gene annotation pipelines and limitations in experimental studies linking phenotype to genotype. This is particularly true for the marine subseafloor, which remains undersampled, but represents the largest contiguous habitat on Earth. To address this limitation, we used FeGenie, a database and bioinformatics tool that identifies microbial iron cycling genes and enables the development of testable hypotheses on the biogeochemical cycling of iron. Herein, we survey the microbial iron cycle in diverse subseafloor habitats, including sediment-buried crustal aquifers, as well as surficial and deep sediments. We inferred the genetic potential for iron redox cycling in 32 of the 46 metagenomes included in our analysis, demonstrating the prevalence of these activities across underexplored subseafloor ecosystems. We show that while some processes (e.g., iron uptake and storage, siderophore transport potential, and iron gene regulation) are near-universal, others (e.g., iron reduction/oxidation, siderophore synthesis, and magnetosome formation) are dependent on local redox and nutrient status. Additionally, we detected niche-specific differences in strategies used for dissimilatory iron reduction, suggesting that geochemical constraints likely play an important role in dictating the dominant mechanisms for iron cycling. Overall, our survey advances the known distribution, magnitude, and potential ecological impact of microbe-mediated iron cycling and utilization in sub-benthic ecosystems.
Collapse
Affiliation(s)
- Arkadiy I Garber
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Ashley B Cohen
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, United States
| | - Kenneth H Nealson
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Gustavo A Ramírez
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel.,College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA, United States
| | - Roman A Barco
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | | | - Michelle M Gehringer
- Department of Microbiology, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Nancy Merino
- Biosciences & Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States
| |
Collapse
|
34
|
Grettenberger CL, Hamilton TL. Metagenome-Assembled Genomes of Novel Taxa from an Acid Mine Drainage Environment. Appl Environ Microbiol 2021; 87:e0077221. [PMID: 34161177 PMCID: PMC8357290 DOI: 10.1128/aem.00772-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/18/2021] [Indexed: 12/13/2022] Open
Abstract
Acid mine drainage (AMD) is a global problem in which iron sulfide minerals oxidize and generate acidic, metal-rich water. Bioremediation relies on understanding how microbial communities inhabiting an AMD site contribute to biogeochemical cycling. A number of studies have reported community composition in AMD sites from 16S rRNA gene amplicons, but it remains difficult to link taxa to function, especially in the absence of closely related cultured species or those with published genomes. Unfortunately, there is a paucity of genomes and cultured taxa from AMD environments. Here, we report 29 novel metagenome-assembled genomes from Cabin Branch, an AMD site in the Daniel Boone National Forest, Kentucky, USA. The genomes span 11 bacterial phyla and one archaeal phylum and include taxa that contribute to carbon, nitrogen, sulfur, and iron cycling. These data reveal overlooked taxa that contribute to carbon fixation in AMD sites as well as uncharacterized Fe(II)-oxidizing bacteria. These data provide additional context for 16S rRNA gene studies, add to our understanding of the taxa involved in biogeochemical cycling in AMD environments, and can inform bioremediation strategies. IMPORTANCE Bioremediating acid mine drainage requires understanding how microbial communities influence geochemical cycling of iron and sulfur and biologically important elements such as carbon and nitrogen. Research in this area has provided an abundance of 16S rRNA gene amplicon data. However, linking these data to metabolisms is difficult because many AMD taxa are uncultured or lack published genomes. Here, we present metagenome-assembled genomes from 29 novel AMD taxa and detail their metabolic potential. These data provide information on AMD taxa that could be important for bioremediation strategies, including taxa that are involved in cycling iron, sulfur, carbon, and nitrogen.
Collapse
Affiliation(s)
| | - Trinity L. Hamilton
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota, USA
- The Biotechnology Institute, University of Minnesota, St. Paul, Minnesota, USA
| |
Collapse
|
35
|
Abstract
Iron (Fe) oxidation is one of Earth’s major biogeochemical processes, key to weathering, soil formation, water quality, and corrosion. However, our understanding of microbial contribution is limited by incomplete knowledge of microbial iron oxidation mechanisms, particularly in neutrophilic iron oxidizers. The genomes of many diverse iron oxidizers encode a homolog to an outer membrane cytochrome (Cyc2) shown to oxidize iron in two acidophiles. Phylogenetic analyses show Cyc2 sequences from neutrophiles cluster together, suggesting a common function, though this function has not been verified in these organisms. Therefore, we investigated the iron oxidase function of heterologously expressed Cyc2 from a neutrophilic iron oxidizer Mariprofundus ferrooxydans PV-1. Cyc2PV-1 is capable of oxidizing iron, and its redox potential is 208 ± 20 mV, consistent with the ability to accept electrons from Fe2+ at neutral pH. These results support the hypothesis that Cyc2 functions as an iron oxidase in neutrophilic iron-oxidizing organisms. The results of sequence analysis and modeling reveal that the entire Cyc2 family shares a unique fused cytochrome-porin structure, with a defining consensus motif in the cytochrome region. On the basis of results from structural analyses, we predict that the monoheme cytochrome Cyc2 specifically oxidizes dissolved Fe2+, in contrast to multiheme iron oxidases, which may oxidize solid Fe(II). With our results, there is now functional validation for diverse representatives of Cyc2 sequences. We present a comprehensive Cyc2 phylogenetic tree and offer a roadmap for identifying cyc2/Cyc2 homologs and interpreting their function. The occurrence of cyc2 in many genomes beyond known iron oxidizers presents the possibility that microbial iron oxidation may be a widespread metabolism.
Collapse
|
36
|
Dong X, Zhang C, Li W, Weng S, Song W, Li J, Wang Y. Functional diversity of microbial communities in inactive seafloor sulfide deposits. FEMS Microbiol Ecol 2021; 97:6327547. [PMID: 34302348 DOI: 10.1093/femsec/fiab108] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 07/22/2021] [Indexed: 11/12/2022] Open
Abstract
The seafloor sulfide structures of inactive vents are known to host abundant and diverse microorganisms potentially supported by mineralogy of sulfides. However, little is known about the diversity and distribution of microbial functions. Here, we used genome-resolved metagenomics to predict microbial metabolic functions and the contribution of horizontal gene transfer to the functionality of microorganisms inhabiting several hydrothermally inactive seafloor deposits among globally distributed deep-sea vent fields. Despite of geographically distant vent fields, similar microbial community patterns were observed with the dominance of Gammaproteobacteria, Bacteroidota and previously overlooked Candidatus Patescibacteria. Metabolically flexible Gammaproteobacteria are major potential primary producers utilizing mainly sulfur, iron and hydrogen as electron donors coupled with oxygen and nitrate respiration for chemolithoautotrophic growth. In addition to heterotrophic microorganisms like free-living Bacteroidota, Ca. Patescibacteria potentially perform fermentative recycling of organic carbon. Finally, we provided evidence that many functional genes that are central to energy metabolism have been laterally transferred among members within the community and largely within the same class. Taken together, these findings shed light on microbial ecology and evolution in inactive seafloor sulfide deposits after the cessation of hydrothermal activities.
Collapse
Affiliation(s)
- Xiyang Dong
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai, 519082, China.,Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China
| | - Chuwen Zhang
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai, 519082, China
| | - Wenli Li
- Department of Life Science, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, 572000, China
| | - Shengze Weng
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai, 519082, China
| | - Weizhi Song
- Centre for Marine Science & Innovation, University of New South Wales, 2052 Sydney, Australia
| | - Jiangtao Li
- State Key Laboratory of Marine Geology, Tongji University, Shanghai, China
| | - Yong Wang
- Department of Life Science, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, 572000, China
| |
Collapse
|
37
|
Huang YM, Straub D, Blackwell N, Kappler A, Kleindienst S. Meta-omics Reveal Gallionellaceae and Rhodanobacter Species as Interdependent Key Players for Fe(II) Oxidation and Nitrate Reduction in the Autotrophic Enrichment Culture KS. Appl Environ Microbiol 2021; 87:e0049621. [PMID: 34020935 PMCID: PMC8276803 DOI: 10.1128/aem.00496-21] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 05/16/2021] [Indexed: 01/04/2023] Open
Abstract
Nitrate reduction coupled to Fe(II) oxidation (NRFO) has been recognized as an environmentally important microbial process in many freshwater ecosystems. However, well-characterized examples of autotrophic nitrate-reducing Fe(II)-oxidizing bacteria are rare, and their pathway of electron transfer as well as their interaction with flanking community members remain largely unknown. Here, we applied meta-omics (i.e., metagenomics, metatranscriptomics, and metaproteomics) to the nitrate-reducing Fe(II)-oxidizing enrichment culture KS growing under autotrophic or heterotrophic conditions and originating from freshwater sediment. We constructed four metagenome-assembled genomes with an estimated completeness of ≥95%, including the key players of NRFO in culture KS, identified as Gallionellaceae sp. and Rhodanobacter sp. The Gallionellaceae sp. and Rhodanobacter sp. transcripts and proteins likely involved in Fe(II) oxidation (e.g., mtoAB, cyc2, and mofA), denitrification (e.g., napGHI), and oxidative phosphorylation (e.g., respiratory chain complexes I to V) along with Gallionellaceae sp. transcripts and proteins for carbon fixation (e.g., rbcL) were detected. Overall, our results indicate that in culture KS, the Gallionellaceae sp. and Rhodanobacter sp. are interdependent: while Gallionellaceae sp. fixes CO2 and provides organic compounds for Rhodanobacter sp., Rhodanobacter sp. likely detoxifies NO through NO reduction and completes denitrification, which cannot be performed by Gallionellaceae sp. alone. Additionally, the transcripts and partial proteins of cbb3- and aa3-type cytochrome c suggest the possibility for a microaerophilic lifestyle of the Gallionellaceae sp., yet culture KS grows under anoxic conditions. Our findings demonstrate that autotrophic NRFO is performed through cooperation among denitrifying and Fe(II)-oxidizing bacteria, which might resemble microbial interactions in freshwater environments. IMPORTANCE Nitrate-reducing Fe(II)-oxidizing bacteria are widespread in the environment, contribute to nitrate removal, and influence the fate of the greenhouse gases nitrous oxide and carbon dioxide. The autotrophic growth of nitrate-reducing Fe(II)-oxidizing bacteria is rarely investigated and not fully understood. The most prominent model system for this type of study is the enrichment culture KS. To gain insights into the metabolism of nitrate reduction coupled to Fe(II) oxidation in the absence of organic carbon and oxygen, we performed metagenomic, metatranscriptomic, and metaproteomic analyses of culture KS and identified Gallionellaceae sp. and Rhodanobacter sp. as interdependent key Fe(II) oxidizers in culture KS. Our work demonstrates that autotrophic nitrate reduction coupled to Fe(II) oxidation is not performed by an individual strain but is a cooperation of at least two members of the bacterial community in culture KS. These findings serve as a foundation for our understanding of nitrate-reducing Fe(II)-oxidizing bacteria in the environment.
Collapse
Affiliation(s)
- Yu-Ming Huang
- Microbial Ecology, Center for Applied Geoscience, University of Tübingen, Tübingen, Germany
- Geomicrobiology, Center for Applied Geoscience, University of Tübingen, Tübingen, Germany
| | - Daniel Straub
- Microbial Ecology, Center for Applied Geoscience, University of Tübingen, Tübingen, Germany
- Quantitative Biology Center (QBiC), University of Tübingen, Tübingen, Germany
| | - Nia Blackwell
- Microbial Ecology, Center for Applied Geoscience, University of Tübingen, Tübingen, Germany
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geoscience, University of Tübingen, Tübingen, Germany
- Cluster of Excellence, EXC 2124, “Controlling Microbes to Fight Infections,” University of Tübingen, Tübingen, Germany
| | - Sara Kleindienst
- Microbial Ecology, Center for Applied Geoscience, University of Tübingen, Tübingen, Germany
| |
Collapse
|
38
|
Lambrecht N, Stevenson Z, Sheik CS, Pronschinske MA, Tong H, Swanner ED. " Candidatus Chlorobium masyuteum," a Novel Photoferrotrophic Green Sulfur Bacterium Enriched From a Ferruginous Meromictic Lake. Front Microbiol 2021; 12:695260. [PMID: 34305861 PMCID: PMC8302410 DOI: 10.3389/fmicb.2021.695260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 06/07/2021] [Indexed: 11/13/2022] Open
Abstract
Anoxygenic phototrophic bacteria can be important primary producers in some meromictic lakes. Green sulfur bacteria (GSB) have been detected in ferruginous lakes, with some evidence that they are photosynthesizing using Fe(II) as an electron donor (i.e., photoferrotrophy). However, some photoferrotrophic GSB can also utilize reduced sulfur compounds, complicating the interpretation of Fe-dependent photosynthetic primary productivity. An enrichment (BLA1) from meromictic ferruginous Brownie Lake, Minnesota, United States, contains an Fe(II)-oxidizing GSB and a metabolically flexible putative Fe(III)-reducing anaerobe. "Candidatus Chlorobium masyuteum" grows photoautotrophically with Fe(II) and possesses the putative Fe(II) oxidase-encoding cyc2 gene also known from oxygen-dependent Fe(II)-oxidizing bacteria. It lacks genes for oxidation of reduced sulfur compounds. Its genome encodes for hydrogenases and a reverse TCA cycle that may allow it to utilize H2 and acetate as electron donors, an inference supported by the abundance of this organism when the enrichment was supplied by these substrates and light. The anaerobe "Candidatus Pseudopelobacter ferreus" is in low abundance (∼1%) in BLA1 and is a putative Fe(III)-reducing bacterium from the Geobacterales ord. nov. While "Ca. C. masyuteum" is closely related to the photoferrotrophs C. ferroooxidans strain KoFox and C. phaeoferrooxidans strain KB01, it is unique at the genomic level. The main light-harvesting molecule was identified as bacteriochlorophyll c with accessory carotenoids of the chlorobactene series. BLA1 optimally oxidizes Fe(II) at a pH of 6.8, and the rate of Fe(II) oxidation was 0.63 ± 0.069 mmol day-1, comparable to other photoferrotrophic GSB cultures or enrichments. Investigation of BLA1 expands the genetic basis for phototrophic Fe(II) oxidation by GSB and highlights the role these organisms may play in Fe(II) oxidation and carbon cycling in ferruginous lakes.
Collapse
Affiliation(s)
- Nicholas Lambrecht
- Department of Geological and Atmospheric Sciences, Iowa State University, Ames, IA, United States
| | - Zackry Stevenson
- Department of Geological and Atmospheric Sciences, Iowa State University, Ames, IA, United States
| | - Cody S. Sheik
- Department of Biology, University of Minnesota Duluth, Duluth, MN, United States
- Large Lakes Observatory, University of Minnesota Duluth, Duluth, MN, United States
| | - Matthew A. Pronschinske
- Department of Geological and Atmospheric Sciences, Iowa State University, Ames, IA, United States
| | - Hui Tong
- Department of Geological and Atmospheric Sciences, Iowa State University, Ames, IA, United States
- Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Institute of Eco-environmental Science and Technology, Guangdong Academy of Sciences, Guangzhou, China
| | - Elizabeth D. Swanner
- Department of Geological and Atmospheric Sciences, Iowa State University, Ames, IA, United States
| |
Collapse
|
39
|
Zhou N, Luther GW, Chan CS. Ligand Effects on Biotic and Abiotic Fe(II) Oxidation by the Microaerophile Sideroxydans lithotrophicus. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:9362-9371. [PMID: 34110796 DOI: 10.1021/acs.est.1c00497] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Organic ligands are widely distributed and can affect microbially driven Fe biogeochemical cycles, but effects on microbial iron oxidation have not been well quantified. Our work used a model microaerophilic Fe(II)-oxidizing bacterium Sideroxydans lithotrophicus ES-1 to quantify biotic Fe(II) oxidation rates in the presence of organic ligands at 0.02 atm O2 and pH 6.0. We used two common Fe chelators with different binding strengths: citrate (log KFe(II)-citrate = 3.20) and nitrilotriacetic acid (NTA) (log KFe(II)-NTA = 8.09) and two standard humic substances, Pahokee peat humic acid (PPHA) and Suwannee River fulvic acid (SRFA). Our results provide rate constants for biotic and abiotic Fe(II) oxidation over different ligand concentrations and furthermore demonstrate that various models and natural iron-binding ligands each have distinct effects on abiotic versus biotic Fe(II) oxidation rates. We show that NTA accelerates abiotic oxidation and citrate has negligible effects, making it a better laboratory chelator. The humic substances only affect biotic Fe(II) oxidation, via a combination of chelation and electron transfer. PPHA accelerates biotic Fe(II) oxidation, while SRFA decelerates or accelerates the rate depending on concentration. The specific nature of organic-Fe microbe interactions may play key roles in environmental Fe(II) oxidation, which have cascading influences on cycling of nutrients and contaminants that associate with Fe oxide minerals.
Collapse
Affiliation(s)
- Nanqing Zhou
- School of Marine Science and Policy, University of Delaware, Newark, Delaware 19716, United States
| | - George W Luther
- School of Marine Science and Policy, University of Delaware, Newark, Delaware 19716, United States
| | - Clara S Chan
- School of Marine Science and Policy, University of Delaware, Newark, Delaware 19716, United States
- Department of Earth Sciences, University of Delaware, Newark, Delaware 19716, United States
| |
Collapse
|
40
|
Koeksoy E, Bezuidt OM, Bayer T, Chan CS, Emerson D. Zetaproteobacteria Pan-Genome Reveals Candidate Gene Cluster for Twisted Stalk Biosynthesis and Export. Front Microbiol 2021; 12:679409. [PMID: 34220764 PMCID: PMC8250860 DOI: 10.3389/fmicb.2021.679409] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 05/06/2021] [Indexed: 12/15/2022] Open
Abstract
Twisted stalks are morphologically unique bacterial extracellular organo-metallic structures containing Fe(III) oxyhydroxides that are produced by microaerophilic Fe(II)-oxidizers belonging to the Betaproteobacteria and Zetaproteobacteria. Understanding the underlying genetic and physiological mechanisms of stalk formation is of great interest based on their potential as novel biogenic nanomaterials and their relevance as putative biomarkers for microbial Fe(II) oxidation on ancient Earth. Despite the recognition of these special biominerals for over 150 years, the genetic foundation for the stalk phenotype has remained unresolved. Here we present a candidate gene cluster for the biosynthesis and secretion of the stalk organic matrix that we identified with a trait-based analyses of a pan-genome comprising 16 Zetaproteobacteria isolate genomes. The “stalk formation in Zetaproteobacteria” (sfz) cluster comprises six genes (sfz1-sfz6), of which sfz1 and sfz2 were predicted with functions in exopolysaccharide synthesis, regulation, and export, sfz4 and sfz6 with functions in cell wall synthesis manipulation and carbohydrate hydrolysis, and sfz3 and sfz5 with unknown functions. The stalk-forming Betaproteobacteria Ferriphaselus R-1 and OYT-1, as well as dread-forming Zetaproteobacteria Mariprofundus aestuarium CP-5 and Mariprofundus ferrinatatus CP-8 contain distant sfz gene homologs, whereas stalk-less Zetaproteobacteria and Betaproteobacteria lack the entire gene cluster. Our pan-genome analysis further revealed a significant enrichment of clusters of orthologous groups (COGs) across all Zetaproteobacteria isolate genomes that are associated with the regulation of a switch between sessile and motile growth controlled by the intracellular signaling molecule c-di-GMP. Potential interactions between stalk-former unique transcription factor genes, sfz genes, and c-di-GMP point toward a c-di-GMP regulated surface attachment function of stalks during sessile growth.
Collapse
Affiliation(s)
- Elif Koeksoy
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United States.,Leibniz Institute DSMZ (German Collection of Microorganisms and Cell Cultures), Braunschweig, Germany
| | - Oliver M Bezuidt
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United States
| | - Timm Bayer
- Geomicrobiology Group, Center for Applied Geoscience, University of Tübingen, Tübingen, Germany
| | - Clara S Chan
- Department of Earth Sciences, University of Delaware, Newark, DE, United States.,School of Marine Sciences and Policy, University of Delaware, Newark, DE, United States
| | - David Emerson
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United States
| |
Collapse
|
41
|
Garcia SL, Mehrshad M, Buck M, Tsuji JM, Neufeld JD, McMahon KD, Bertilsson S, Greening C, Peura S. Freshwater Chlorobia Exhibit Metabolic Specialization among Cosmopolitan and Endemic Populations. mSystems 2021; 6:e01196-20. [PMID: 33975970 PMCID: PMC8125076 DOI: 10.1128/msystems.01196-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 04/09/2021] [Indexed: 01/15/2023] Open
Abstract
Photosynthetic bacteria from the class Chlorobia (formerly phylum Chlorobi) sustain carbon fixation in anoxic water columns. They harvest light at extremely low intensities and use various inorganic electron donors to fix carbon dioxide into biomass. Until now, most information on the functional ecology and local adaptations of Chlorobia members came from isolates and merely 26 sequenced genomes that may not adequately represent natural populations. To address these limitations, we analyzed global metagenomes to profile planktonic Chlorobia cells from the oxyclines of 42 freshwater bodies, spanning subarctic to tropical regions and encompassing all four seasons. We assembled and compiled over 500 genomes, including metagenome-assembled genomes (MAGs), single-amplified genomes (SAGs), and reference genomes from cultures, clustering them into 71 metagenomic operational taxonomic units (mOTUs or "species"). Of the 71 mOTUs, 57 were classified within the genus Chlorobium, and these mOTUs represented up to ∼60% of the microbial communities in the sampled anoxic waters. Several Chlorobium-associated mOTUs were globally distributed, whereas others were endemic to individual lakes. Although most clades encoded the ability to oxidize hydrogen, many lacked genes for the oxidation of specific sulfur and iron substrates. Surprisingly, one globally distributed Scandinavian clade encoded the ability to oxidize hydrogen, sulfur, and iron, suggesting that metabolic versatility facilitated such widespread colonization. Overall, these findings provide new insight into the biogeography of the Chlorobia and the metabolic traits that facilitate niche specialization within lake ecosystems.IMPORTANCE The reconstruction of genomes from metagenomes has helped explore the ecology and evolution of environmental microbiota. We applied this approach to 274 metagenomes collected from diverse freshwater habitats that spanned oxic and anoxic zones, sampling seasons, and latitudes. We demonstrate widespread and abundant distributions of planktonic Chlorobia-associated bacteria in hypolimnetic waters of stratified freshwater ecosystems and show they vary in their capacities to use different electron donors. Having photoautotrophic potential, these Chlorobia members could serve as carbon sources that support metalimnetic and hypolimnetic food webs.
Collapse
Affiliation(s)
- Sarahi L Garcia
- Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden
- Department of Ecology, Environment, and Plant Sciences, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Maliheh Mehrshad
- Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Uppsala, Sweden
| | - Moritz Buck
- Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Uppsala, Sweden
| | - Jackson M Tsuji
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Josh D Neufeld
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Katherine D McMahon
- Department of Civil and Environmental Engineering, University of Wisconsin, Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin, Madison, Madison, Wisconsin, USA
| | - Stefan Bertilsson
- Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Uppsala, Sweden
| | - Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Sari Peura
- Department of Forest Mycology and Plant Pathology, Science for Life Laboratory, Swedish University of Agricultural Sciences, Uppsala, Uppsala, Sweden
| |
Collapse
|
42
|
Jiang V, Khare SD, Banta S. Computational structure prediction provides a plausible mechanism for electron transfer by the outer membrane protein Cyc2 from Acidithiobacillus ferrooxidans. Protein Sci 2021; 30:1640-1652. [PMID: 33969560 DOI: 10.1002/pro.4106] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 12/14/2022]
Abstract
Cyc2 is the key protein in the outer membrane of Acidithiobacillus ferrooxidans that mediates electron transfer between extracellular inorganic iron and the intracellular central metabolism. This cytochrome c is specific for iron and interacts with periplasmic proteins to complete a reversible electron transport chain. A structure of Cyc2 has not yet been characterized experimentally. Here we describe a structural model of Cyc2, and associated proteins, to highlight a plausible mechanism for the ferrous iron electron transfer chain. A comparative modeling protocol specific for trans membrane beta barrel (TMBB) proteins in acidophilic conditions (pH ~ 2) was applied to the primary sequence of Cyc2. The proposed structure has three main regimes: Extracellular loops exposed to low-pH conditions, a TMBB, and an N-terminal cytochrome-like region within the periplasmic space. The Cyc2 model was further refined by identifying likely iron and heme docking sites. This represents the first computational model of Cyc2 that accounts for the membrane microenvironment and the acidity in the extracellular matrix. This approach can be used to model other TMBBs which can be critical for chemolithotrophic microbial growth.
Collapse
Affiliation(s)
- Virginia Jiang
- Department of Chemical Engineering, Columbia University in the City of New York, New York, New York, USA
| | - Sagar D Khare
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Scott Banta
- Department of Chemical Engineering, Columbia University in the City of New York, New York, New York, USA
| |
Collapse
|
43
|
Zeng X, Alain K, Shao Z. Microorganisms from deep-sea hydrothermal vents. MARINE LIFE SCIENCE & TECHNOLOGY 2021; 3:204-230. [PMID: 37073341 PMCID: PMC10077256 DOI: 10.1007/s42995-020-00086-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 11/17/2020] [Indexed: 05/03/2023]
Abstract
With a rich variety of chemical energy sources and steep physical and chemical gradients, hydrothermal vent systems offer a range of habitats to support microbial life. Cultivation-dependent and independent studies have led to an emerging view that diverse microorganisms in deep-sea hydrothermal vents live their chemolithoautotrophic, heterotrophic, or mixotrophic life with versatile metabolic strategies. Biogeochemical processes are mediated by microorganisms, and notably, processes involving or coupling the carbon, sulfur, hydrogen, nitrogen, and metal cycles in these unique ecosystems. Here, we review the taxonomic and physiological diversity of microbial prokaryotic life from cosmopolitan to endemic taxa and emphasize their significant roles in the biogeochemical processes in deep-sea hydrothermal vents. According to the physiology of the targeted taxa and their needs inferred from meta-omics data, the media for selective cultivation can be designed with a wide range of physicochemical conditions such as temperature, pH, hydrostatic pressure, electron donors and acceptors, carbon sources, nitrogen sources, and growth factors. The application of novel cultivation techniques with real-time monitoring of microbial diversity and metabolic substrates and products are also recommended. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-020-00086-4.
Collapse
Affiliation(s)
- Xiang Zeng
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005 China
- LIA/IRP 1211 MicrobSea, Sino-French International Laboratory of Deep-Sea Microbiology, 29280 Plouzané, France
| | - Karine Alain
- Laboratoire de Microbiologie des Environnements Extrêmes LM2E UMR6197, Univ Brest, CNRS, IFREMER, F-29280 Plouzané, France
- LIA/IRP 1211 MicrobSea, Sino-French International Laboratory of Deep-Sea Microbiology, 29280 Plouzané, France
| | - Zongze Shao
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005 China
- LIA/IRP 1211 MicrobSea, Sino-French International Laboratory of Deep-Sea Microbiology, 29280 Plouzané, France
| |
Collapse
|
44
|
Little CTS, Johannessen KC, Bengtson S, Chan CS, Ivarsson M, Slack JF, Broman C, Thorseth IH, Grenne T, Rouxel OJ, Bekker A. A late Paleoproterozoic (1.74 Ga) deep-sea, low-temperature, iron-oxidizing microbial hydrothermal vent community from Arizona, USA. GEOBIOLOGY 2021; 19:228-249. [PMID: 33594795 DOI: 10.1111/gbi.12434] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 01/18/2021] [Accepted: 02/01/2021] [Indexed: 06/12/2023]
Abstract
Modern marine hydrothermal vents occur in a wide variety of tectonic settings and are characterized by seafloor emission of fluids rich in dissolved chemicals and rapid mineral precipitation. Some hydrothermal systems vent only low-temperature Fe-rich fluids, which precipitate deposits dominated by iron oxyhydroxides, in places together with Mn-oxyhydroxides and amorphous silica. While a proportion of this mineralization is abiogenic, most is the result of the metabolic activities of benthic, Fe-oxidizing bacteria (FeOB), principally belonging to the Zetaproteobacteria. These micro-organisms secrete micrometer-scale stalks, sheaths, and tubes with a variety of morphologies, composed largely of ferrihydrite that act as sacrificial structures, preventing encrustation of the cells that produce them. Cultivated marine FeOB generally require neutral pH and microaerobic conditions to grow. Here, we describe the morphology and mineralogy of filamentous microstructures from a late Paleoproterozoic (1.74 Ga) jasper (Fe-oxide-silica) deposit from the Jerome area of the Verde mining district in central Arizona, USA, that resemble the branching tubes formed by some modern marine FeOB. On the basis of this comparison, we interpret the Jerome area filaments as having formed by FeOB on the deep seafloor, at the interface of weakly oxygenated seawater and low-temperature Fe-rich hydrothermal fluids. We compare the Jerome area filaments with other purported examples of Precambrian FeOB and discuss the implications of their presence for existing redox models of Paleoproterozoic oceans during the "Boring Billion."
Collapse
Affiliation(s)
| | | | - Stefan Bengtson
- Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, Sweden
| | - Clara S Chan
- Department of Earth Sciences, University of Delaware, Newark, USA
| | - Magnus Ivarsson
- Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, Sweden
- Department of Biology, University of Southern Denmark, Odense M, Denmark
| | - John F Slack
- U.S. Geological Survey (Emeritus), National Center, Reston, USA
| | - Curt Broman
- Department of Geological Sciences, Stockholm University, Stockholm, Sweden
| | | | - Tor Grenne
- Geological Survey of Norway, Trondheim, Norway
| | | | - Andrey Bekker
- Department of Earth and Planetary Sciences, University of California, Riverside, USA
- Department of Geology, University of Johannesburg, Johannesburg, South Africa
| |
Collapse
|
45
|
Kappler A, Bryce C, Mansor M, Lueder U, Byrne JM, Swanner ED. An evolving view on biogeochemical cycling of iron. Nat Rev Microbiol 2021; 19:360-374. [PMID: 33526911 DOI: 10.1038/s41579-020-00502-7] [Citation(s) in RCA: 187] [Impact Index Per Article: 62.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/08/2020] [Indexed: 01/23/2023]
Abstract
Biogeochemical cycling of iron is crucial to many environmental processes, such as ocean productivity, carbon storage, greenhouse gas emissions and the fate of nutrients, toxic metals and metalloids. Knowledge of the underlying processes involved in iron cycling has accelerated in recent years along with appreciation of the complex network of biotic and abiotic reactions dictating the speciation, mobility and reactivity of iron in the environment. Recent studies have provided insights into novel processes in the biogeochemical iron cycle such as microbial ammonium oxidation and methane oxidation coupled to Fe(III) reduction. They have also revealed that processes in the biogeochemical iron cycle spatially overlap and may compete with each other, and that oxidation and reduction of iron occur cyclically or simultaneously in many environments. This Review discusses these advances with particular focus on their environmental consequences, including the formation of greenhouse gases and the fate of nutrients and contaminants.
Collapse
Affiliation(s)
- Andreas Kappler
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen, Tübingen, Germany.
| | - Casey Bryce
- School of Earth Sciences, University of Bristol, Bristol, UK
| | - Muammar Mansor
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen, Tübingen, Germany
| | - Ulf Lueder
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen, Tübingen, Germany
| | - James M Byrne
- School of Earth Sciences, University of Bristol, Bristol, UK
| | - Elizabeth D Swanner
- Department of Geological and Atmospheric Sciences, Iowa State University, Ames, IA, USA
| |
Collapse
|
46
|
Napieralski SA, Roden EE. The Weathering Microbiome of an Outcropping Granodiorite. Front Microbiol 2021; 11:601907. [PMID: 33381096 PMCID: PMC7767972 DOI: 10.3389/fmicb.2020.601907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 11/26/2020] [Indexed: 11/13/2022] Open
Abstract
Microorganisms have long been recognized for their capacity to catalyze the weathering of silicate minerals. While the vast majority of studies on microbially mediated silicate weathering focus on organotrophic metabolism linked to nutrient acquisition, it has been recently demonstrated that chemolithotrophic ferrous iron [Fe(II)] oxidizing bacteria (FeOB) are capable of coupling the oxidation of silicate mineral Fe(II) to metabolic energy generation and cellular growth. In natural systems, complex microbial consortia with diverse metabolic capabilities can exist and interact to influence the biogeochemical cycling of essential elements, including iron. Here we combine microbiological and metagenomic analyses to investigate the potential interactions among metabolically diverse microorganisms in the near surface weathering of an outcrop of the Rio Blanco Quartz Diorite (DIO) in the Luquillo Mountains of Puerto Rico. Laboratory based incubations utilizing ground DIO as metabolic energy source for chemolithotrophic FeOB confirmed the ability of FeOB to grow via the oxidation of silicate-bound Fe(II). Dramatically accelerated rates of Fe(II)-oxidation were associated with an enrichment in microorganisms with the genetic capacity for iron oxidizing extracellular electron transfer (EET) pathways. Microbially oxidized DIO displayed an enhanced susceptibility to the weathering activity of organotrophic microorganisms compared to unoxidized mineral suspensions. Our results suggest that chemolithotrophic and organotrophic microorganisms are likely to coexist and contribute synergistically to the overall weathering of the in situ bedrock outcrop.
Collapse
Affiliation(s)
| | - Eric E Roden
- Department of Geoscience, University of Wisconsin-Madison, Madison, WI, United States
| |
Collapse
|
47
|
Aerobic and anaerobic iron oxidizers together drive denitrification and carbon cycling at marine iron-rich hydrothermal vents. ISME JOURNAL 2020; 15:1271-1286. [PMID: 33328652 PMCID: PMC8114936 DOI: 10.1038/s41396-020-00849-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 11/06/2020] [Accepted: 11/18/2020] [Indexed: 12/02/2022]
Abstract
In principle, iron oxidation can fuel significant primary productivity and nutrient cycling in dark environments such as the deep sea. However, we have an extremely limited understanding of the ecology of iron-based ecosystems, and thus the linkages between iron oxidation, carbon cycling, and nitrate reduction. Here we investigate iron microbial mats from hydrothermal vents at Lōʻihi Seamount, Hawaiʻi, using genome-resolved metagenomics and metatranscriptomics to reconstruct potential microbial roles and interactions. Our results show that the aerobic iron-oxidizing Zetaproteobacteria are the primary producers, concentrated at the oxic mat surface. Their fixed carbon supports heterotrophs deeper in the mat, notably the second most abundant organism, Candidatus Ferristratum sp. (uncultivated gen. nov.) from the uncharacterized DTB120 phylum. Candidatus Ferristratum sp., described using nine high-quality metagenome-assembled genomes with similar distributions of genes, expressed nitrate reduction genes narGH and the iron oxidation gene cyc2 in situ and in response to Fe(II) in a shipboard incubation, suggesting it is an anaerobic nitrate-reducing iron oxidizer. Candidatus Ferristratum sp. lacks a full denitrification pathway, relying on Zetaproteobacteria to remove intermediates like nitrite. Thus, at Lōʻihi, anaerobic iron oxidizers coexist with and are dependent on aerobic iron oxidizers. In total, our work shows how key community members work together to connect iron oxidation with carbon and nitrogen cycling, thus driving the biogeochemistry of exported fluids.
Collapse
|
48
|
Akob DM, Hallenbeck M, Beulig F, Fabisch M, Küsel K, Keffer JL, Woyke T, Shapiro N, Lapidus A, Klenk HP, Chan CS. Mixotrophic Iron-Oxidizing Thiomonas Isolates from an Acid Mine Drainage-Affected Creek. Appl Environ Microbiol 2020; 86:e01424-20. [PMID: 33008825 PMCID: PMC7688216 DOI: 10.1128/aem.01424-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 09/30/2020] [Indexed: 12/27/2022] Open
Abstract
Natural attenuation of heavy metals occurs via coupled microbial iron cycling and metal precipitation in creeks impacted by acid mine drainage (AMD). Here, we describe the isolation, characterization, and genomic sequencing of two iron-oxidizing bacteria (FeOB) species: Thiomonas ferrovorans FB-6 and Thiomonas metallidurans FB-Cd, isolated from slightly acidic (pH 6.3), Fe-rich, AMD-impacted creek sediments. These strains precipitated amorphous iron oxides, lepidocrocite, goethite, and magnetite or maghemite and grew at a pH optimum of 5.5. While Thiomonas spp. are known as mixotrophic sulfur oxidizers and As oxidizers, the FB strains oxidized Fe, which suggests they can efficiently remove Fe and other metals via coprecipitation. Previous evidence for Thiomonas sp. Fe oxidation is largely ambiguous, possibly because of difficulty demonstrating Fe oxidation in heterotrophic/mixotrophic organisms. Therefore, we also conducted a genomic analysis to identify genetic mechanisms of Fe oxidation, other metal transformations, and additional adaptations, comparing the two FB strain genomes with 12 other Thiomonas genomes. The FB strains fall within a relatively novel group of Thiomonas strains that includes another strain (b6) with solid evidence of Fe oxidation. Most Thiomonas isolates, including the FB strains, have the putative iron oxidation gene cyc2, but only the two FB strains possess the putative Fe oxidase genes mtoAB The two FB strain genomes contain the highest numbers of strain-specific gene clusters, greatly increasing the known Thiomonas genetic potential. Our results revealed that the FB strains are two distinct novel species of Thiomonas with the genetic potential for bioremediation of AMD via iron oxidation.IMPORTANCE As AMD moves through the environment, it impacts aquatic ecosystems, but at the same time, these ecosystems can naturally attenuate contaminated waters via acid neutralization and catalyzing metal precipitation. This is the case in the former Ronneburg uranium-mining district, where AMD impacts creek sediments. We isolated and characterized two iron-oxidizing Thiomonas species that are mildly acidophilic to neutrophilic and that have two genetic pathways for iron oxidation. These Thiomonas species are well positioned to naturally attenuate AMD as it discharges across the landscape.
Collapse
Affiliation(s)
| | - Michelle Hallenbeck
- Department of Biological Sciences, University of Delaware, Newark, Delaware, USA
- Delaware Biotechnology Institute, Newark, Delaware, USA
| | - Felix Beulig
- Institute of Biodiversity, Friedrich Schiller University Jena, Jena, Germany
| | - Maria Fabisch
- Institute of Biodiversity, Friedrich Schiller University Jena, Jena, Germany
| | - Kirsten Küsel
- Institute of Biodiversity, Friedrich Schiller University Jena, Jena, Germany
| | - Jessica L Keffer
- Department of Earth Sciences, University of Delaware, Newark, Delaware, USA
- Delaware Biotechnology Institute, Newark, Delaware, USA
| | - Tanja Woyke
- Joint Genome Institute, U.S. Department of Energy, Berkeley, California, USA
| | - Nicole Shapiro
- Joint Genome Institute, U.S. Department of Energy, Berkeley, California, USA
| | - Alla Lapidus
- Joint Genome Institute, U.S. Department of Energy, Berkeley, California, USA
- Center for Algorithmic Biotechnology, St. Petersburg State University, St. Petersburg, Russia
| | - Hans-Peter Klenk
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Clara S Chan
- Department of Biological Sciences, University of Delaware, Newark, Delaware, USA
- Department of Earth Sciences, University of Delaware, Newark, Delaware, USA
- Delaware Biotechnology Institute, Newark, Delaware, USA
| |
Collapse
|
49
|
Tsuji JM, Tran N, Schiff SL, Venkiteswaran JJ, Molot LA, Tank M, Hanada S, Neufeld JD. Anoxygenic photosynthesis and iron-sulfur metabolic potential of Chlorobia populations from seasonally anoxic Boreal Shield lakes. THE ISME JOURNAL 2020; 14:2732-2747. [PMID: 32747714 PMCID: PMC7784702 DOI: 10.1038/s41396-020-0725-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/02/2020] [Accepted: 07/20/2020] [Indexed: 12/16/2022]
Abstract
Aquatic environments with high levels of dissolved ferrous iron and low levels of sulfate serve as an important systems for exploring biogeochemical processes relevant to the early Earth. Boreal Shield lakes, which number in the tens of millions globally, commonly develop seasonally anoxic waters that become iron rich and sulfate poor, yet the iron-sulfur microbiology of these systems has been poorly examined. Here we use genome-resolved metagenomics and enrichment cultivation to explore the metabolic diversity and ecology of anoxygenic photosynthesis and iron/sulfur cycling in the anoxic water columns of three Boreal Shield lakes. We recovered four high-completeness and low-contamination draft genome bins assigned to the class Chlorobia (formerly phylum Chlorobi) from environmental metagenome data and enriched two novel sulfide-oxidizing species, also from the Chlorobia. The sequenced genomes of both enriched species, including the novel "Candidatus Chlorobium canadense", encoded the cyc2 gene that is associated with photoferrotrophy among cultured Chlorobia members, along with genes for phototrophic sulfide oxidation. One environmental genome bin also encoded cyc2. Despite the presence of cyc2 in the corresponding draft genome, we were unable to induce photoferrotrophy in "Ca. Chlorobium canadense". Genomic potential for phototrophic sulfide oxidation was more commonly detected than cyc2 among environmental genome bins of Chlorobia, and metagenome and cultivation data suggested the potential for cryptic sulfur cycling to fuel sulfide-based growth. Overall, our results provide an important basis for further probing the functional role of cyc2 and indicate that anoxygenic photoautotrophs in Boreal Shield lakes could have underexplored photophysiology pertinent to understanding Earth's early microbial communities.
Collapse
Affiliation(s)
- J M Tsuji
- University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada
| | - N Tran
- University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada
| | - S L Schiff
- University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada
| | - J J Venkiteswaran
- University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada
- Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON, N2L 3C5, Canada
| | - L A Molot
- York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada
| | - M Tank
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures GmbH, Inhoffenstrasse 7B, 38124, Braunschweig, Germany
- Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, 192-0397, Japan
| | - S Hanada
- Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, 192-0397, Japan
| | - J D Neufeld
- University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada.
| |
Collapse
|
50
|
Gupta D, Guzman MS, Bose A. Extracellular electron uptake by autotrophic microbes: physiological, ecological, and evolutionary implications. ACTA ACUST UNITED AC 2020; 47:863-876. [DOI: 10.1007/s10295-020-02309-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/07/2020] [Indexed: 02/05/2023]
Abstract
Abstract
Microbes exchange electrons with their extracellular environment via direct or indirect means. This exchange is bidirectional and supports essential microbial oxidation–reduction processes, such as respiration and photosynthesis. The microbial capacity to use electrons from insoluble electron donors, such as redox-active minerals, poised electrodes, or even other microbial cells is called extracellular electron uptake (EEU). Autotrophs with this capability can thrive in nutrient and soluble electron donor-deficient environments. As primary producers, autotrophic microbes capable of EEU greatly impact microbial ecology and play important roles in matter and energy flow in the biosphere. In this review, we discuss EEU-driven autotrophic metabolisms, their mechanism and physiology, and highlight their ecological, evolutionary, and biotechnological implications.
Collapse
Affiliation(s)
- Dinesh Gupta
- grid.4367.6 0000 0001 2355 7002 Department of Biology Washington University in St. Louis One Brookings Drive 63130 St. Louis MO USA
| | - Michael S Guzman
- grid.250008.f 0000 0001 2160 9702 Biosciences and Biotechnology Division Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory Livermore CA USA
| | - Arpita Bose
- grid.4367.6 0000 0001 2355 7002 Department of Biology Washington University in St. Louis One Brookings Drive 63130 St. Louis MO USA
| |
Collapse
|