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Schaible GA, Jay ZJ, Cliff J, Schulz F, Gauvin C, Goudeau D, Malmstrom RR, Ruff SE, Edgcomb V, Hatzenpichler R. Multicellular magnetotactic bacteria are genetically heterogeneous consortia with metabolically differentiated cells. PLoS Biol 2024; 22:e3002638. [PMID: 38990824 PMCID: PMC11239054 DOI: 10.1371/journal.pbio.3002638] [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: 12/18/2023] [Accepted: 04/24/2024] [Indexed: 07/13/2024] Open
Abstract
Consortia of multicellular magnetotactic bacteria (MMB) are currently the only known example of bacteria without a unicellular stage in their life cycle. Because of their recalcitrance to cultivation, most previous studies of MMB have been limited to microscopic observations. To study the biology of these unique organisms in more detail, we use multiple culture-independent approaches to analyze the genomics and physiology of MMB consortia at single-cell resolution. We separately sequenced the metagenomes of 22 individual MMB consortia, representing 8 new species, and quantified the genetic diversity within each MMB consortium. This revealed that, counter to conventional views, cells within MMB consortia are not clonal. Single consortia metagenomes were then used to reconstruct the species-specific metabolic potential and infer the physiological capabilities of MMB. To validate genomic predictions, we performed stable isotope probing (SIP) experiments and interrogated MMB consortia using fluorescence in situ hybridization (FISH) combined with nanoscale secondary ion mass spectrometry (NanoSIMS). By coupling FISH with bioorthogonal noncanonical amino acid tagging (BONCAT), we explored their in situ activity as well as variation of protein synthesis within cells. We demonstrate that MMB consortia are mixotrophic sulfate reducers and that they exhibit metabolic differentiation between individual cells, suggesting that MMB consortia are more complex than previously thought. These findings expand our understanding of MMB diversity, ecology, genomics, and physiology, as well as offer insights into the mechanisms underpinning the multicellular nature of their unique lifestyle.
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Affiliation(s)
- George A. Schaible
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, United States of America
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, United States of America
| | - Zackary J. Jay
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, United States of America
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, United States of America
- Thermal Biology Institute, Montana State University, Bozeman, Montana, United States of America
| | - John Cliff
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Frederik Schulz
- Department of Energy Joint Genome Institute, Berkeley, California, United States of America
| | - Colin Gauvin
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, United States of America
- Thermal Biology Institute, Montana State University, Bozeman, Montana, United States of America
| | - Danielle Goudeau
- Department of Energy Joint Genome Institute, Berkeley, California, United States of America
| | - Rex R. Malmstrom
- Department of Energy Joint Genome Institute, Berkeley, California, United States of America
| | - S. Emil Ruff
- Ecosystems Center and Bay Paul Center, Marine Biological Laboratory, Woods Hole, Massachusetts, United States of America
| | - Virginia Edgcomb
- Woods Hole Oceanographic Institution, Falmouth, Massachusetts, United States of America
| | - Roland Hatzenpichler
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, United States of America
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, United States of America
- Thermal Biology Institute, Montana State University, Bozeman, Montana, United States of America
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, United States of America
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Schaible GA, Jay ZJ, Cliff J, Schulz F, Gauvin C, Goudeau D, Malmstrom RR, Emil Ruff S, Edgcomb V, Hatzenpichler R. Multicellular magnetotactic bacterial consortia are metabolically differentiated and not clonal. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.27.568837. [PMID: 38076927 PMCID: PMC10705294 DOI: 10.1101/2023.11.27.568837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2023]
Abstract
Consortia of multicellular magnetotactic bacteria (MMB) are currently the only known example of bacteria without a unicellular stage in their life cycle. Because of their recalcitrance to cultivation, most previous studies of MMB have been limited to microscopic observations. To study the biology of these unique organisms in more detail, we use multiple culture-independent approaches to analyze the genomics and physiology of MMB consortia at single cell resolution. We separately sequenced the metagenomes of 22 individual MMB consortia, representing eight new species, and quantified the genetic diversity within each MMB consortium. This revealed that, counter to conventional views, cells within MMB consortia are not clonal. Single consortia metagenomes were then used to reconstruct the species-specific metabolic potential and infer the physiological capabilities of MMB. To validate genomic predictions, we performed stable isotope probing (SIP) experiments and interrogated MMB consortia using fluorescence in situ hybridization (FISH) combined with nano-scale secondary ion mass spectrometry (NanoSIMS). By coupling FISH with bioorthogonal non-canonical amino acid tagging (BONCAT) we explored their in situ activity as well as variation of protein synthesis within cells. We demonstrate that MMB consortia are mixotrophic sulfate reducers and that they exhibit metabolic differentiation between individual cells, suggesting that MMB consortia are more complex than previously thought. These findings expand our understanding of MMB diversity, ecology, genomics, and physiology, as well as offer insights into the mechanisms underpinning the multicellular nature of their unique lifestyle.
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Affiliation(s)
- George A. Schaible
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717
- Center for Biofilm Engineering, Montana State University, Bozeman, MT 59717
| | - Zackary J. Jay
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717
- Center for Biofilm Engineering, Montana State University, Bozeman, MT 59717
- Thermal Biology Institute, Montana State University, Bozeman, MT 59717
| | - John Cliff
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99354
| | - Frederik Schulz
- Department of Energy Joint Genome Institute, Berkeley, CA, 94720
| | - Colin Gauvin
- Center for Biofilm Engineering, Montana State University, Bozeman, MT 59717
- Thermal Biology Institute, Montana State University, Bozeman, MT 59717
| | - Danielle Goudeau
- Department of Energy Joint Genome Institute, Berkeley, CA, 94720
| | - Rex R. Malmstrom
- Department of Energy Joint Genome Institute, Berkeley, CA, 94720
| | - S. Emil Ruff
- Ecosystems Center and Bay Paul Center, Marine Biological Laboratory, Woods Hole, MA, 02543
| | | | - Roland Hatzenpichler
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717
- Center for Biofilm Engineering, Montana State University, Bozeman, MT 59717
- Thermal Biology Institute, Montana State University, Bozeman, MT 59717
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717
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Chavhan Y, Dey S, Lind PA. Bacteria evolve macroscopic multicellularity by the genetic assimilation of phenotypically plastic cell clustering. Nat Commun 2023; 14:3555. [PMID: 37322016 PMCID: PMC10272148 DOI: 10.1038/s41467-023-39320-9] [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: 09/20/2022] [Accepted: 06/05/2023] [Indexed: 06/17/2023] Open
Abstract
The evolutionary transition from unicellularity to multicellularity was a key innovation in the history of life. Experimental evolution is an important tool to study the formation of undifferentiated cellular clusters, the likely first step of this transition. Although multicellularity first evolved in bacteria, previous experimental evolution research has primarily used eukaryotes. Moreover, it focuses on mutationally driven (and not environmentally induced) phenotypes. Here we show that both Gram-negative and Gram-positive bacteria exhibit phenotypically plastic (i.e., environmentally induced) cell clustering. Under high salinity, they form elongated clusters of ~ 2 cm. However, under habitual salinity, the clusters disintegrate and grow planktonically. We used experimental evolution with Escherichia coli to show that such clustering can be assimilated genetically: the evolved bacteria inherently grow as macroscopic multicellular clusters, even without environmental induction. Highly parallel mutations in genes linked to cell wall assembly formed the genomic basis of assimilated multicellularity. While the wildtype also showed cell shape plasticity across high versus low salinity, it was either assimilated or reversed after evolution. Interestingly, a single mutation could genetically assimilate multicellularity by modulating plasticity at multiple levels of organization. Taken together, we show that phenotypic plasticity can prime bacteria for evolving undifferentiated macroscopic multicellularity.
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Affiliation(s)
- Yashraj Chavhan
- Department of Molecular Biology, Umeå University, Umeå, Sweden.
| | - Sutirth Dey
- Indian Institute of Science Education and Research (IISER) Pune, Pune, India
| | - Peter A Lind
- Department of Molecular Biology, Umeå University, Umeå, Sweden.
- Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden.
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Moreno MA, Ofria C. Exploring Evolved Multicellular Life Histories in a Open-Ended Digital Evolution System. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.750837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Evolutionary transitions occur when previously-independent replicating entities unite to form more complex individuals. Such transitions have profoundly shaped natural evolutionary history and occur in two forms: fraternal transitions involve lower-level entities that are kin (e.g., transitions to multicellularity or to eusocial colonies), while egalitarian transitions involve unrelated individuals (e.g., the origins of mitochondria). The necessary conditions and evolutionary mechanisms for these transitions to arise continue to be fruitful targets of scientific interest. Here, we examine a range of fraternal transitions in populations of open-ended self-replicating computer programs. These digital cells were allowed to form and replicate kin groups by selectively adjoining or expelling daughter cells. The capability to recognize kin-group membership enabled preferential communication and cooperation between cells. We repeatedly observed group-level traits that are characteristic of a fraternal transition. These included reproductive division of labor, resource sharing within kin groups, resource investment in offspring groups, asymmetrical behaviors mediated by messaging, morphological patterning, and adaptive apoptosis. We report eight case studies from replicates where transitions occurred and explore the diverse range of adaptive evolved multicellular strategies.
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Adams AE, Besozzi EM, Shahrokhi G, Patten MA. A case for associational resistance: Apparent support for the stress gradient hypothesis varies with study system. Ecol Lett 2021; 25:202-217. [PMID: 34775662 DOI: 10.1111/ele.13917] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 09/07/2021] [Accepted: 10/18/2021] [Indexed: 11/30/2022]
Abstract
According to the stress gradient hypothesis (SGH), ecological interactions between organisms shift positively as environmental stress increases. In the case of associational resistance, habitat is modified to ameliorate stress, benefitting other organisms. The SGH is contentious due to conflicting evidence and theoretical perspectives, so we adopted a meta-analytic approach to determine if it is widely supported across a variety of contexts, including different kingdoms, ecosystems, habitats, interactions, stressors, and life history stages. We developed an extensive list of Boolean search criteria to search the published ecological literature and successfully detect studies that both directly tested the hypothesis, and those that were relevant but never mentioned it. We found that the SGH is well supported by studies that feature bacteria, plants, terrestrial ecosystems, interspecific negative interactions, adults, survival instead of growth or reproduction, and drought, fire, and nutrient stress. We conclude that the SGH is indeed a broadly relevant ecological hypothesis that is currently held back by cross-disciplinary communication barriers. More SGH research is needed beyond the scope of interspecific plant competition, and more SGH research should feature multifactor stress. There remains a need to account for positive interactions in scientific pursuits, such as associational resistance in tests of the SGH.
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Affiliation(s)
- Amy E Adams
- Department of Biology, University of Oklahoma, Norman, Oklahoma, USA
| | | | - Golya Shahrokhi
- Oklahoma Biological Survey, University of Oklahoma, Norman, Oklahoma, USA
| | - Michael A Patten
- Ecology Research Group, Faculty of Biosciences and Aquaculture, Nord University, Steinkjer, Norway
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Gitschlag BL, Tate AT, Patel MR. Nutrient status shapes selfish mitochondrial genome dynamics across different levels of selection. eLife 2020; 9:56686. [PMID: 32959778 PMCID: PMC7508553 DOI: 10.7554/elife.56686] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 08/17/2020] [Indexed: 12/23/2022] Open
Abstract
Cooperation and cheating are widespread evolutionary strategies. While cheating confers an advantage to individual entities within a group, competition between groups favors cooperation. Selfish or cheater mitochondrial DNA (mtDNA) proliferates within hosts while being selected against at the level of host fitness. How does environment shape cheater dynamics across different selection levels? Focusing on food availability, we address this question using heteroplasmic Caenorhabditis elegans. We find that the proliferation of selfish mtDNA within hosts depends on nutrient status stimulating mtDNA biogenesis in the developing germline. Interestingly, mtDNA biogenesis is not sufficient for this proliferation, which also requires the stress-response transcription factor FoxO/DAF-16. At the level of host fitness, FoxO/DAF-16 also prevents food scarcity from accelerating the selection against selfish mtDNA. This suggests that the ability to cope with nutrient stress can promote host tolerance of cheaters. Our study delineates environmental effects on selfish mtDNA dynamics at different levels of selection.
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Affiliation(s)
- Bryan L Gitschlag
- Department of Biological Sciences, Vanderbilt University, Nashville, United States
| | - Ann T Tate
- Department of Biological Sciences, Vanderbilt University, Nashville, United States
| | - Maulik R Patel
- Department of Biological Sciences, Vanderbilt University, Nashville, United States.,Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, United States.,Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, United States
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