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Panwar P, Allen MA, Williams TJ, Haque S, Brazendale S, Hancock AM, Paez-Espino D, Cavicchioli R. Remarkably coherent population structure for a dominant Antarctic Chlorobium species. MICROBIOME 2021; 9:231. [PMID: 34823595 PMCID: PMC8620254 DOI: 10.1186/s40168-021-01173-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 10/09/2021] [Indexed: 05/22/2023]
Abstract
BACKGROUND In Antarctica, summer sunlight enables phototrophic microorganisms to drive primary production, thereby "feeding" ecosystems to enable their persistence through the long, dark winter months. In Ace Lake, a stratified marine-derived system in the Vestfold Hills of East Antarctica, a Chlorobium species of green sulphur bacteria (GSB) is the dominant phototroph, although its seasonal abundance changes more than 100-fold. Here, we analysed 413 Gb of Antarctic metagenome data including 59 Chlorobium metagenome-assembled genomes (MAGs) from Ace Lake and nearby stratified marine basins to determine how genome variation and population structure across a 7-year period impacted ecosystem function. RESULTS A single species, Candidatus Chlorobium antarcticum (most similar to Chlorobium phaeovibrioides DSM265) prevails in all three aquatic systems and harbours very little genomic variation (≥ 99% average nucleotide identity). A notable feature of variation that did exist related to the genomic capacity to biosynthesize cobalamin. The abundance of phylotypes with this capacity changed seasonally ~ 2-fold, consistent with the population balancing the value of a bolstered photosynthetic capacity in summer against an energetic cost in winter. The very high GSB concentration (> 108 cells ml-1 in Ace Lake) and seasonal cycle of cell lysis likely make Ca. Chlorobium antarcticum a major provider of cobalamin to the food web. Analysis of Ca. Chlorobium antarcticum viruses revealed the species to be infected by generalist (rather than specialist) viruses with a broad host range (e.g., infecting Gammaproteobacteria) that were present in diverse Antarctic lakes. The marked seasonal decrease in Ca. Chlorobium antarcticum abundance may restrict specialist viruses from establishing effective lifecycles, whereas generalist viruses may augment their proliferation using other hosts. CONCLUSION The factors shaping Antarctic microbial communities are gradually being defined. In addition to the cold, the annual variation in sunlight hours dictates which phototrophic species can grow and the extent to which they contribute to ecosystem processes. The Chlorobium population studied was inferred to provide cobalamin, in addition to carbon, nitrogen, hydrogen, and sulphur cycling, as critical ecosystem services. The specific Antarctic environmental factors and major ecosystem benefits afforded by this GSB likely explain why such a coherent population structure has developed in this Chlorobium species. Video abstract.
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Affiliation(s)
- Pratibha Panwar
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, 2052, Australia
| | - Michelle A Allen
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, 2052, Australia
| | - Timothy J Williams
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, 2052, Australia
| | - Sabrina Haque
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, 2052, Australia
- Present address: Department of Molecular Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia
| | - Sarah Brazendale
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, 2052, Australia
- , Present address: Pegarah, Australia
| | - Alyce M Hancock
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, 2052, Australia
- Present address: Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Battery Point, Tasmania, Australia
| | - David Paez-Espino
- Department of Energy Joint Genome Institute, Berkeley, CA, USA
- Present address: Mammoth Biosciences, Inc., 1000 Marina Blvd. Suite 600, Brisbane, CA, USA
| | - Ricardo Cavicchioli
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, 2052, Australia.
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Shoji S, Ogawa T, Hashishin T, Tamiaki H. Self-Assemblies of Zinc Bacteriochlorophyll-d Analogues Having Amide, Ester, and Urea Groups as Substituents at 17-Position and Observation of Lamellar Supramolecular Nanostructures. Chemphyschem 2018; 19:913-920. [PMID: 29231276 DOI: 10.1002/cphc.201701044] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 12/07/2017] [Indexed: 11/05/2022]
Abstract
Chlorosomes are unique light-harvesting apparatuses in photosynthetic green bacteria. Single chlorosomes contain a large number of bacteriochlorophyll (BChl)-c, -d, -e, and -f molecules, which self-assemble without protein assistance. These BChl self-assemblies involving specific intermolecular interactions (Mg⋅⋅⋅O32 -H⋅⋅⋅O=C131 and π-π stacks of chlorin skeletons) in a chlorosome have been reported to be round-shaped rods (or tubes) with diameters of 5 or 10 nm, or lamellae with a layer spacing of approximately 2 nm. Herein, the self-assembly of synthetic zinc BChl-d analogues having ester, amide, and urea groups in the 17-substituent is reported. Spectroscopic analyses indicate that the zinc BChl-d analogues self-assemble in a nonpolar organic solvent in a similar manner to natural chlorosomal BChls with additional assistance by hydrogen-bonding of secondary amide (or urea) groups (CON-H⋅⋅⋅O=CNH). Microscopic analyses of the supramolecules of a zinc BChl-d analogue bearing amide and urea groups show round- or square-shaped rods with widths of about 65 nm. Cryogenic TEM shows a lamellar arrangement of the zinc chlorin with a layer spacing of 1.5 nm inside the rod. Similar thick rods are also visible in the micrographs of self-assemblies of zinc BChl-d analogues with one or two secondary amide moieties in the 17-substituent.
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Affiliation(s)
- Sunao Shoji
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Tetsuya Ogawa
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Takeshi Hashishin
- Faculty of Engineering, Kumamoto University, Kumamoto, Kumamoto, 860-8555, Japan
| | - Hitoshi Tamiaki
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
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Orf GS, Collins AM, Niedzwiedzki DM, Tank M, Thiel V, Kell A, Bryant DA, Montaño GA, Blankenship RE. Polymer-Chlorosome Nanocomposites Consisting of Non-Native Combinations of Self-Assembling Bacteriochlorophylls. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:6427-6438. [PMID: 28585832 DOI: 10.1021/acs.langmuir.7b01761] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Chlorosomes are one of the characteristic light-harvesting antennas from green sulfur bacteria. These complexes represent a unique paradigm: self-assembly of bacteriochlorophyll pigments within a lipid monolayer without the influence of protein. Because of their large size and reduced complexity, they have been targeted as models for the development of bioinspired light-harvesting arrays. We report the production of biohybrid light-harvesting nanocomposites mimicking chlorosomes, composed of amphiphilic diblock copolymer membrane bodies that incorporate thousands of natural self-assembling bacteriochlorophyll molecules derived from green sulfur bacteria. The driving force behind the assembly of these polymer-chlorosome nanocomposites is the transfer of the mixed raw materials from the organic to the aqueous phase. We incorporated up to five different self-assembling pigment types into single nanocomposites that mimic chlorosome morphology. We establish that the copolymer-BChl self-assembly process works smoothly even when non-native combinations of BChl homologues are included. Spectroscopic characterization revealed that the different types of self-assembling pigments participate in ultrafast energy transfer, expanding beyond single chromophore constraints of the natural chlorosome system. This study further demonstrates the utility of flexible short-chain, diblock copolymers for building scalable, tunable light-harvesting arrays for technological use and allows for an in vitro analysis of the flexibility of natural self-assembling chromophores in unique and controlled combinations.
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Affiliation(s)
| | - Aaron M Collins
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | | | - Marcus Tank
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
- Department of Biological Sciences, Tokyo Metropolitan University , Tokyo, Japan 192-0397
| | - Vera Thiel
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
- Department of Biological Sciences, Tokyo Metropolitan University , Tokyo, Japan 192-0397
| | - Adam Kell
- Department of Chemistry, Kansas State University , Manhattan, Kansas 66506, United States
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
| | - Gabriel A Montaño
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
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Pollich M, Klug G. Identification and sequence analysis of genes involved in late steps in cobalamin (vitamin B12) synthesis in Rhodobacter capsulatus. J Bacteriol 1995; 177:4481-7. [PMID: 7635831 PMCID: PMC177200 DOI: 10.1128/jb.177.15.4481-4487.1995] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
A 6.4-kb region of a 6.8-kb BamHI fragment carrying Rhodobacter capsulatus genes involved in late steps of cobalamin synthesis has been sequenced. The nucleotide sequence and genetic analysis revealed that this fragment contains eight genes arranged in at least three operons. Five of these eight genes show homology to genes involved in the cobalamin synthesis of Pseudomonas denitrificans and Salmonella typhimurium. The arrangement of these homologous genes differs considerably in the three genera. Upstream of five overlapping genes (named bluFEDCB), a promoter activity could be detected by using lacZ fusions. This promoter shows no regulation by oxygen, vitamin B12 (cobalamin), or cobinamide. Disruption of the bluE gene by a Tn5 insertion (strain AH2) results in reduced expression of the puf and puc operons, which encode pigment-binding proteins of the photosynthetic apparatus. The mutant strain AH2 can be corrected to a wild-type-like phenotype by addition of vitamin B12 or cobinamide dicyanide. Disruption of the bluB gene by an interposon (strain BB1) also disturbs the formation of the photosynthetic apparatus. The mutation of strain BB1 can be corrected by vitamin B12 but not by cobinamide. We propose that a lack of cobalamin results in deregulation and a decreased formation of the photosynthetic apparatus.
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Affiliation(s)
- M Pollich
- Institut für Mikro- und Molekularbiologie, Giessen, Germany
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