1
|
Pan H, Shim A, Lubin MB, Belin BJ. Hopanoid lipids promote soybean -Bradyrhizobium symbiosis. mBio 2024; 15:e0247823. [PMID: 38445860 PMCID: PMC11005386 DOI: 10.1128/mbio.02478-23] [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: 09/14/2023] [Accepted: 01/04/2024] [Indexed: 03/07/2024] Open
Abstract
The symbioses between leguminous plants and nitrogen-fixing bacteria known as rhizobia are well known for promoting plant growth and sustainably increasing soil nitrogen. Recent evidence indicates that hopanoids, a family of steroid-like lipids, promote Bradyrhizobium symbioses with tropical legumes. To characterize hopanoids in Bradyrhizobium symbiosis with soybean, we validated a recently published cumate-inducible hopanoid mutant of Bradyrhizobium diazoefficiens USDA110, Pcu-shc::∆shc. GC-MS analysis showed that this strain does not produce hopanoids without cumate induction, and under this condition, is impaired in growth in rich medium and under osmotic, temperature, and pH stress. In planta, Pcu-shc::∆shc is an inefficient soybean symbiont with significantly lower rates of nitrogen fixation and low survival within the host tissue. RNA-seq revealed that hopanoid loss reduces the expression of flagellar motility and chemotaxis-related genes, further confirmed by swim plate assays, and enhances the expression of genes related to nitrogen metabolism and protein secretion. These results suggest that hopanoids provide a significant fitness advantage to B. diazoefficiens in legume hosts and provide a foundation for future mechanistic studies of hopanoid function in protein secretion and motility. A major problem for global sustainability is feeding our exponentially growing human population while available arable land decreases. Harnessing the power of plant-beneficial microbes is a potential solution, including increasing our reliance on the symbioses of leguminous plants and nitrogen-fixing rhizobia. This study examines the role of hopanoid lipids in the symbiosis between Bradyrhizobium diazoefficiens USDA110, an important commercial inoculant strain, and its economically significant host soybean. Our research extends our knowledge of the functions of bacterial lipids in symbiosis to an agricultural context, which may one day help improve the practical applications of plant-beneficial microbes in agriculture.
Collapse
Affiliation(s)
- Huiqiao Pan
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland, USA
| | - Ashley Shim
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland, USA
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Matthew B. Lubin
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland, USA
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Brittany J. Belin
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland, USA
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| |
Collapse
|
2
|
Pan H, Shim A, Lubin MB, Belin BJ. Hopanoid lipids promote soybean- Bradyrhizobium symbiosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.04.556284. [PMID: 37732186 PMCID: PMC10508751 DOI: 10.1101/2023.09.04.556284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
The symbioses between leguminous plants and nitrogen-fixing bacteria known as rhizobia are well known for promoting plant growth and sustainably increasing soil nitrogen. Recent evidence indicates that hopanoids, a family of steroid-like lipids, promote Bradyrhizobium symbioses with tropical legumes. To characterize hopanoids in Bradyrhizobium symbiosis with soybean, the most economically significant Bradyrhizobium host, we validated a recently published cumate-inducible hopanoid mutant of Bradyrhizobium diazoefficiens USDA110, Pcu- shc ::Δ shc . GC-MS analysis showed that this strain does not produce hopanoids without cumate induction, and under this condition, is impaired in growth in rich medium and under osmotic, temperature, and pH stress. In planta , Pcu- shc ::Δ shc is an inefficient soybean symbiont with significantly lower rates of nitrogen fixation and low survival within host tissue. RNA-seq revealed that hopanoid loss reduces expression of flagellar motility and chemotaxis-related genes, further confirmed by swim plate assays, and enhances expression of genes related to nitrogen metabolism and protein secretion. These results suggest that hopanoids provide a significant fitness advantage to B. diazoefficiens in legume hosts and provide a foundation for future mechanistic studies of hopanoid function in protein secretion and motility. IMPORTANCE A major problem for global sustainability is feeding our exponentially growing human population while available arable land is decreasing, especially in areas with the greatest population growth. Harnessing the power of plant-beneficial microbes has gained attention as a potential solution, including the increasing our reliance on the symbioses of leguminous plants and nitrogen-fixing rhizobia. This study examines the role of hopanoid lipids in the symbiosis between Bradyrhizobium diazoefficiens USDA110, an important commercial inoculant strain, and its economically important host soybean. Our research extends our knowledge of the functions of bacterial lipids in symbiosis to an agricultural context, which may one day help improve the practical applications of plant-beneficial microbes in agriculture.
Collapse
|
3
|
Mrudulakumari Vasudevan U, Mai DHA, Krishna S, Lee EY. Methanotrophs as a reservoir for bioactive secondary metabolites: Pitfalls, insights and promises. Biotechnol Adv 2023; 63:108097. [PMID: 36634856 DOI: 10.1016/j.biotechadv.2023.108097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 12/10/2022] [Accepted: 01/06/2023] [Indexed: 01/11/2023]
Abstract
Methanotrophs are potent natural producers of several bioactive secondary metabolites (SMs) including isoprenoids, polymers, peptides, and vitamins. Cryptic biosynthetic gene clusters identified from these microbes via genome mining hinted at the vast and hidden SM biosynthetic potential of these microbes. Central carbon metabolism in methanotrophs offers rare pathway intermediate pools that could be further diversified using advanced synthetic biology tools to produce valuable SMs; for example, plant polyketides, rare carotenoids, and fatty acid-derived SMs. Recent advances in pathway reconstruction and production of isoprenoids, squalene, ectoine, polyhydroxyalkanoate copolymer, cadaverine, indigo, and shinorine serve as proof-of-concept. This review provides theoretical guidance for developing methanotrophs as microbial chassis for high-value SMs. We summarize the distinct secondary metabolic potentials of type I and type II methanotrophs, with specific attention to products relevant to biomedical applications. This review also includes native and non-native SMs from methanotrophs, their therapeutic potential, strategies to induce silent biosynthetic gene clusters, and challenges.
Collapse
Affiliation(s)
- Ushasree Mrudulakumari Vasudevan
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Republic of Korea
| | - Dung Hoang Anh Mai
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Republic of Korea
| | - Shyam Krishna
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Republic of Korea
| | - Eun Yeol Lee
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Republic of Korea.
| |
Collapse
|
4
|
Sala D, Grossi V, Agogué H, Leboulanger C, Jézéquel D, Sarazin G, Antheaume I, Bernard C, Ader M, Hugoni M. Influence of aphotic haloclines and euxinia on organic biomarkers and microbial communities in a thalassohaline and alkaline volcanic crater lake. GEOBIOLOGY 2022; 20:292-309. [PMID: 34687126 DOI: 10.1111/gbi.12477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 09/29/2021] [Accepted: 10/06/2021] [Indexed: 06/13/2023]
Abstract
Studies on microbial communities, and their associated organic biomarkers, that are found thriving in the aphotic euxinic waters in modern stratified ecosystems are scarce compared to those undertaken in euxinic photic zones. The Dziani Dzaha (Mayotte, Indian Ocean) is a tropical, saline, alkaline crater lake that has recently been presented as a modern analog of Proterozoic Oceans due to its thalassohaline classification (having water of marine origin) and specific biogeochemical characteristics. Continuous intense photosynthetic production and microbial mineralization keep most of the water column permanently aphotic and anoxic preventing the development of a euxinic (sulfidic and anoxic) photic zone despite a high sulfide/sulfate ratio and the presence of permanent or seasonal haloclines. In this study, the molecular composition of the organic matter in Lake Dziani Dzaha was investigated and compared to the microbial diversity evaluated through 16S rRNA gene amplicon sequencing, over two contrasting seasons (rainy vs. dry) that influence water column stratification. Depth profiles of organic biomarker concentrations (chlorophyll-a and lipid biomarkers) and bacterial and archaeal OTU abundances appeared to be strongly dependent on the presence of aphotic haloclines and euxinia. OTU abundances revealed the importance of specific haloalkaliphilic bacterial and archaeal assemblages in phytoplanktonic biomass recycling and the biogeochemical functioning of the lake, suggesting new haloalkaline non-phototrophic anaerobic microbial precursors for some of the lipid biomarkers. Uncultured Firmicutes from the family Syntrophomonadaceae (Clostridiales), and Bacteroidetes from the ML635J-40 aquatic group, emerged as abundant chemotrophic bacterial members in the anoxic or euxinic waters and were probably responsible for the production of short-chain n-alkenes, wax esters, diplopterol, and tetrahymanol. Halocline-dependent euxinia also had a strong impact on the archaeal community which was dominated by Woesearchaeota in the sulfide-free waters. In the euxinic waters, methanogenic Euryarchaeota from the Methanomicrobia, Thermoplasmata, and WSA2 classes dominated and were likely at the origin of common hydrocarbon biomarkers of methanogens (phytane, pentamethyl-eicosenes, and partially hydrogenated squalene).
Collapse
Affiliation(s)
- David Sala
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENSL, UJM, LGL-TPE, Villeurbanne, France
| | - Vincent Grossi
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENSL, UJM, LGL-TPE, Villeurbanne, France
| | - Hélène Agogué
- LIENSs, UMR 7266, La Rochelle Université - CNRS, La Rochelle, France
| | | | - Didier Jézéquel
- Université de Paris, Institut de Physique du Globe de Paris, Paris, France
- INRAE & Université Savoie Mont Blanc, UMR CARRTEL, Thonon-les-Bains, France
| | - Gérard Sarazin
- Université de Paris, Institut de Physique du Globe de Paris, Paris, France
| | - Ingrid Antheaume
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENSL, UJM, LGL-TPE, Villeurbanne, France
| | - Cécile Bernard
- UMR 7245 Molécules de Communication et Adaptations des Microorganismes (MCAM) MNHN-CNRS, Muséum National d'Histoire Naturelle, Paris, France
| | - Magali Ader
- Université de Paris, Institut de Physique du Globe de Paris, Paris, France
| | - Mylène Hugoni
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, Villeurbanne, France
- Univ Lyon, INSA Lyon, CNRS, UMR 5240 Microbiologie Adaptation et Pathogénie, Villeurbanne, France
- Institut Universitaire de France, Paris, France
| |
Collapse
|
5
|
Summons RE, Welander PV, Gold DA. Lipid biomarkers: molecular tools for illuminating the history of microbial life. Nat Rev Microbiol 2022; 20:174-185. [PMID: 34635851 DOI: 10.1038/s41579-021-00636-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2021] [Indexed: 11/09/2022]
Abstract
Fossilized lipids preserved in sedimentary rocks offer singular insights into the Earth's palaeobiology. These 'biomarkers' encode information pertaining to the oxygenation of the atmosphere and oceans, transitions in ocean plankton, the greening of continents, mass extinctions and climate change. Historically, biomarker interpretations relied on inventories of lipids present in extant microorganisms and counterparts in natural environments. However, progress has been impeded because only a small fraction of the Earth's microorganisms can be cultured, many environmentally significant microorganisms from the past no longer exist and there are gaping holes in knowledge concerning lipid biosynthesis. The revolution in genomics and bioinformatics has provided new tools to expand our understanding of lipid biomarkers, their biosynthetic pathways and distributions in nature. In this Review, we explore how preserved organic molecules provide a unique perspective on the history of the Earth's microbial life. We discuss how advances in molecular biology have helped elucidate biomarker origins and afforded more robust interpretations of fossil lipids and how the rock record provides vital calibration points for molecular clocks. Such studies are open to further exploitation with the expansion of sequenced microbial genomes in accessible databases.
Collapse
Affiliation(s)
- Roger E Summons
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Paula V Welander
- Department of Earth System Science, Stanford University, Stanford, CA, USA
| | - David A Gold
- Department of Earth & Planetary Sciences, University of California Davis, Davis, CA, USA
| |
Collapse
|
6
|
Hu Z, Wang C, Pan L, Han S, Jin M, Xiang Y, Zheng L, Li Z, Cao R, Qin B. Identification and a phased pH control strategy of diosgenin bio-synthesized by an endogenous Bacillus licheniformis Syt1 derived from Dioscorea zingiberensis C. H. Wright. Appl Microbiol Biotechnol 2021; 105:9333-9342. [PMID: 34841464 DOI: 10.1007/s00253-021-11679-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 10/07/2021] [Accepted: 11/02/2021] [Indexed: 11/28/2022]
Abstract
Diosgenin is widely used as one precursor of steroidal drugs in pharmaceutical industry. Currently, there is no choice but to traditionally extract diosgenin from Dioscorea zingiberensis C. H. Wright (DZW) or other plants. In this work, an environmentally friendly approach, in which diosgenin can be bio-synthesized by the endophytic bacterium Bacillus licheniformis Syt1 isolated from DZW, is proposed. Diosgenin produced by the strain was identified by high-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR), and Fourier transform infrared spectroscopy (FTIR). The thermal gravimetric analysis (TGA) showed that the melting point of the diosgenin product was 204 °C. The optical rotation measurement exhibited that the optical rotation was α20589 = - 126.1° ± 1.5° (chloroform, c = 1%): negative sign means that the product is left-handed, which is very important to further produce steroid hormone drugs. Cholesterol may be the intermediate product in the diosgenin biosynthesis pathway. In the batch fermentation process to produce diosgenin using the strain, pH values played an important role. A phased pH control strategy from 5.5 to 7.5 was proved to be more effective to improve production yield than any single pH control, which could get the highest diosgenin yield of 85 ± 8.6 mg L-1. The proposed method may replace phyto-chemistry extraction to produce diosgenin in the industry in the future.Key points• An endophytic Bacillus licheniformis Syt1 derived from host can produce diosgenin.• A dynamic pH industrial control strategy is better than any single pH control.• Proposed diosgenin-produced method hopefully replaces phyto-chemistry extraction.
Collapse
Affiliation(s)
- Zhongqiu Hu
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Chunli Wang
- YangLing Demonstration Zone Hospital, Yangling, Shaanxi, 712100, People's Republic of China
| | - Lintao Pan
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Shiyao Han
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Miao Jin
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Yongsheng Xiang
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Lifei Zheng
- College of Science, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Zhonghong Li
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Rang Cao
- College of Grassland Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Baofu Qin
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
| |
Collapse
|
7
|
Bouwknegt J, Wiersma SJ, Ortiz-Merino RA, Doornenbal ESR, Buitenhuis P, Giera M, Müller C, Pronk JT. A squalene-hopene cyclase in Schizosaccharomyces japonicus represents a eukaryotic adaptation to sterol-limited anaerobic environments. Proc Natl Acad Sci U S A 2021; 118:e2105225118. [PMID: 34353908 PMCID: PMC8364164 DOI: 10.1073/pnas.2105225118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Biosynthesis of sterols, which are key constituents of canonical eukaryotic membranes, requires molecular oxygen. Anaerobic protists and deep-branching anaerobic fungi are the only eukaryotes in which a mechanism for sterol-independent growth has been elucidated. In these organisms, tetrahymanol, formed through oxygen-independent cyclization of squalene by a squalene-tetrahymanol cyclase, acts as a sterol surrogate. This study confirms an early report [C. J. E. A. Bulder, Antonie Van Leeuwenhoek, 37, 353-358 (1971)] that Schizosaccharomyces japonicus is exceptional among yeasts in growing anaerobically on synthetic media lacking sterols and unsaturated fatty acids. Mass spectrometry of lipid fractions of anaerobically grown Sch. japonicus showed the presence of hopanoids, a class of cyclic triterpenoids not previously detected in yeasts, including hop-22(29)-ene, hop-17(21)-ene, hop-21(22)-ene, and hopan-22-ol. A putative gene in Sch. japonicus showed high similarity to bacterial squalene-hopene cyclase (SHC) genes and in particular to those of Acetobacter species. No orthologs of the putative Sch. japonicus SHC were found in other yeast species. Expression of the Sch. japonicus SHC gene (Sjshc1) in Saccharomyces cerevisiae enabled hopanoid synthesis and stimulated anaerobic growth in sterol-free media, thus indicating that one or more of the hopanoids produced by SjShc1 could at least partially replace sterols. Use of hopanoids as sterol surrogates represents a previously unknown adaptation of eukaryotic cells to anaerobic growth. The fast anaerobic growth of Sch. japonicus in sterol-free media is an interesting trait for developing robust fungal cell factories for application in anaerobic industrial processes.
Collapse
Affiliation(s)
- Jonna Bouwknegt
- Department of Biotechnology, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Sanne J Wiersma
- Department of Biotechnology, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Raúl A Ortiz-Merino
- Department of Biotechnology, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Eline S R Doornenbal
- Department of Biotechnology, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Petrik Buitenhuis
- Department of Biotechnology, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Martin Giera
- Center for Proteomics and Metabolomics, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Christoph Müller
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximillians University Munich, 81377 Munich, Germany
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, 2629 HZ Delft, The Netherlands;
| |
Collapse
|
8
|
Lamb DC, Hargrove TY, Zhao B, Wawrzak Z, Goldstone JV, Nes WD, Kelly SL, Waterman MR, Stegeman JJ, Lepesheva GI. Concerning P450 Evolution: Structural Analyses Support Bacterial Origin of Sterol 14α-Demethylases. Mol Biol Evol 2021; 38:952-967. [PMID: 33031537 PMCID: PMC7947880 DOI: 10.1093/molbev/msaa260] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Sterol biosynthesis, primarily associated with eukaryotic kingdoms of life, occurs as an abbreviated pathway in the bacterium Methylococcus capsulatus. Sterol 14α-demethylation is an essential step in this pathway and is catalyzed by cytochrome P450 51 (CYP51). In M. capsulatus, the enzyme consists of the P450 domain naturally fused to a ferredoxin domain at the C-terminus (CYP51fx). The structure of M. capsulatus CYP51fx was solved to 2.7 Å resolution and is the first structure of a bacterial sterol biosynthetic enzyme. The structure contained one P450 molecule per asymmetric unit with no electron density seen for ferredoxin. We connect this with the requirement of P450 substrate binding in order to activate productive ferredoxin binding. Further, the structure of the P450 domain with bound detergent (which replaced the substrate upon crystallization) was solved to 2.4 Å resolution. Comparison of these two structures to the CYP51s from human, fungi, and protozoa reveals strict conservation of the overall protein architecture. However, the structure of an "orphan" P450 from nonsterol-producing Mycobacterium tuberculosis that also has CYP51 activity reveals marked differences, suggesting that loss of function in vivo might have led to alterations in the structural constraints. Our results are consistent with the idea that eukaryotic and bacterial CYP51s evolved from a common cenancestor and that early eukaryotes may have recruited CYP51 from a bacterial source. The idea is supported by bioinformatic analysis, revealing the presence of CYP51 genes in >1,000 bacteria from nine different phyla, >50 of them being natural CYP51fx fusion proteins.
Collapse
Affiliation(s)
- David C Lamb
- Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
| | - Tatiana Y Hargrove
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN
| | - Bin Zhao
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN
| | - Zdzislaw Wawrzak
- Synchrotron Research Center, Life Science Collaborative Access Team, Northwestern University, Argonne, IL
| | - Jared V Goldstone
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA
| | - William David Nes
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX
| | - Steven L Kelly
- Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
| | - Michael R Waterman
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN
| | - John J Stegeman
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA
| | - Galina I Lepesheva
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN.,Center for Structural Biology, Vanderbilt University, Nashville, TN
| |
Collapse
|
9
|
Darnet S, Blary A, Chevalier Q, Schaller H. Phytosterol Profiles, Genomes and Enzymes - An Overview. FRONTIERS IN PLANT SCIENCE 2021; 12:665206. [PMID: 34093623 PMCID: PMC8172173 DOI: 10.3389/fpls.2021.665206] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 04/20/2021] [Indexed: 05/12/2023]
Abstract
The remarkable diversity of sterol biosynthetic capacities described in living organisms is enriched at a fast pace by a growing number of sequenced genomes. Whereas analytical chemistry has produced a wealth of sterol profiles of species in diverse taxonomic groups including seed and non-seed plants, algae, phytoplanktonic species and other unicellular eukaryotes, functional assays and validation of candidate genes unveils new enzymes and new pathways besides canonical biosynthetic schemes. An overview of the current landscape of sterol pathways in the tree of life is tentatively assembled in a series of sterolotypes that encompass major groups and provides also peculiar features of sterol profiles in bacteria, fungi, plants, and algae.
Collapse
Affiliation(s)
| | | | | | - Hubert Schaller
- Plant Isoprenoid Biology Team, Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, Strasbourg, France
| |
Collapse
|
10
|
Cordova-Gonzalez A, Birgel D, Kappler A, Peckmann J. Variation of salinity and nitrogen concentration affects the pentacyclic triterpenoid inventory of the haloalkaliphilic aerobic methanotrophic bacterium Methylotuvimicrobium alcaliphilum. Extremophiles 2021; 25:285-299. [PMID: 33866428 PMCID: PMC8102298 DOI: 10.1007/s00792-021-01228-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 04/01/2021] [Indexed: 11/30/2022]
Abstract
The occurrence and activity of aerobic methanotrophs are influenced by environmental conditions, including pH, temperature, salinity, methane and oxygen concentrations, and nutrient availability. Aerobic methanotrophs synthesize a variety of lipids important for cell functions. However, culture-based experiments studying the influence of environmental parameters on lipid production by aerobic methanotrophs are scarce. Such information is crucial to interpret lipid patterns of methanotrophic bacteria in the environment. In this study, the alkaliphilic strain Methylotuvimicrobium alcaliphilum was cultivated under different salinities and different nitrate concentrations to assess the effect of changing conditions on the inventory of pentacyclic triterpenoids. The results indicate that hopanoid abundance is enhanced at lower salinity and higher nitrate concentration. The production of most pentacyclic triterpenoids was favored at low salinity, especially for aminotriol. Interestingly, 3-methyl-aminotetrol and tetrahymanol were favored at higher salinity. Bacteriohopanepolyols (BHPs), particularly aminotriol and 3-methyl-aminotriol, increased considerably at higher nitrate concentrations. Four novel N-containing BHPs—aminodiol, 3-methyl-aminodiol, and isomers of aminotriol and 3-methyl-aminotriol—were identified. This study highlights the significance of environmental factors for bacterial lipid production and documents the need for cultivation studies under variable conditions to utilize the full potential of the biomarker concept.
Collapse
Affiliation(s)
- Alexmar Cordova-Gonzalez
- Institut für Geologie, Centrum für Erdsystemforschung und Nachhaltigkeit, Universität Hamburg, Hamburg, Germany
| | - Daniel Birgel
- Institut für Geologie, Centrum für Erdsystemforschung und Nachhaltigkeit, Universität Hamburg, Hamburg, Germany.
| | - Andreas Kappler
- Geomikrobiologie, Zentrum für Angewandte Geowissenschaften, Universität Tübingen, Tübingen, Germany
| | - Jörn Peckmann
- Institut für Geologie, Centrum für Erdsystemforschung und Nachhaltigkeit, Universität Hamburg, Hamburg, Germany
| |
Collapse
|
11
|
Sistiaga A, Husain F, Uribelarrea D, Martín-Perea DM, Ferland T, Freeman KH, Diez-Martín F, Baquedano E, Mabulla A, Domínguez-Rodrigo M, Summons RE. Microbial biomarkers reveal a hydrothermally active landscape at Olduvai Gorge at the dawn of the Acheulean, 1.7 Ma. Proc Natl Acad Sci U S A 2020; 117:24720-24728. [PMID: 32934140 PMCID: PMC7547214 DOI: 10.1073/pnas.2004532117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Landscape-scale reconstructions of ancient environments within the cradle of humanity may reveal insights into the relationship between early hominins and the changing resources around them. Many studies of Olduvai Gorge during Pliocene-Pleistocene times have revealed the presence of precession-driven wet-dry cycles atop a general aridification trend, though may underestimate the impact of local-scale conditions on early hominins, who likely experienced a varied and more dynamic landscape. Fossil lipid biomarkers from ancient plants and microbes encode information about their surroundings via their molecular structures and composition, and thus can shed light on past environments. Here, we employ fossil lipid biomarkers to study the paleolandscape at Olduvai Gorge at the emergence of the Acheulean technology, 1.7 Ma, through the Lower Augitic Sandstones layer. In the context of the expansion of savanna grasslands, our results represent a resource-rich mosaic ecosystem populated by groundwater-fed rivers, aquatic plants, angiosperm shrublands, and edible plants. Evidence of a geothermally active landscape is reported via an unusual biomarker distribution consistent with the presence of hydrothermal features seen today at Yellowstone National Park. The study of hydrothermalism in ancient settings and its impact on hominin evolution has not been addressed before, although the association of thermal springs in the proximity of archaeological sites documented here can also be found at other localities. The hydrothermal features and resources present at Olduvai Gorge may have allowed early hominins to thermally process edible plants and meat, supporting the possibility of a prefire stage of human evolution.
Collapse
Affiliation(s)
- Ainara Sistiaga
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139;
- GLOBE Institute, University of Copenhagen, 1350 Copenhagen, Denmark
| | - Fatima Husain
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - David Uribelarrea
- Institute of Evolution in Africa (IDEA), University of Alcalá, 28010, Madrid, Spain
- Geodynamics, Stratigraphy and Palaeontology Department, Complutense University of Madrid, 28040 Madrid, Spain
| | - David M Martín-Perea
- Institute of Evolution in Africa (IDEA), University of Alcalá, 28010, Madrid, Spain
- Geodynamics, Stratigraphy and Palaeontology Department, Complutense University of Madrid, 28040 Madrid, Spain
- Paleobiology Department, National Natural Sciences Museum, Consejo Superior de Investigaciones Científicas, 28006 Madrid, Spain
| | - Troy Ferland
- Department of Geosciences, The Pennsylvania State University, University Park, PA 16802
| | - Katherine H Freeman
- Department of Geosciences, The Pennsylvania State University, University Park, PA 16802
| | - Fernando Diez-Martín
- Department of Prehistory and Archaeology, Universidad de Valladolid, 47002 Valladolid, Spain
| | | | - Audax Mabulla
- Department of Archaeology and Heritage Studies, University of Dar es Salaam, 35050 Dar es Salaam, Tanzania
| | - Manuel Domínguez-Rodrigo
- Institute of Evolution in Africa (IDEA), University of Alcalá, 28010, Madrid, Spain
- Department of Philosophy and History (Area of Prehistory), University of Alcalá, 28801 Alcalá de Henares, Spain
| | - Roger E Summons
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139
| |
Collapse
|
12
|
Squalene-Tetrahymanol Cyclase Expression Enables Sterol-Independent Growth of Saccharomyces cerevisiae. Appl Environ Microbiol 2020; 86:AEM.00672-20. [PMID: 32561581 PMCID: PMC7440791 DOI: 10.1128/aem.00672-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 06/14/2020] [Indexed: 02/08/2023] Open
Abstract
The laboratory experiments described in this report simulate a proposed horizontal gene transfer event during the evolution of strictly anaerobic fungi. The demonstration that expression of a single heterologous gene sufficed to eliminate anaerobic sterol requirements in the model eukaryote Saccharomyces cerevisiae therefore contributes to our understanding of how sterol-independent eukaryotes evolved in anoxic environments. This report provides a proof of principle for a metabolic engineering strategy to eliminate sterol requirements in yeast strains that are applied in large-scale anaerobic industrial processes. The sterol-independent yeast strains described in this report provide a valuable platform for further studies on the physiological roles and impacts of sterols and sterol surrogates in eukaryotic cells. Biosynthesis of sterols, which are considered essential components of virtually all eukaryotic membranes, requires molecular oxygen. Anaerobic growth of the yeast Saccharomyces cerevisiae therefore strictly depends on sterol supplementation of synthetic growth media. Neocallimastigomycota are a group of strictly anaerobic fungi which, instead of containing sterols, contain the pentacyclic triterpenoid “sterol surrogate” tetrahymanol, which is formed by cyclization of squalene. Here, we demonstrate that expression of the squalene-tetrahymanol cyclase gene TtTHC1 from the ciliate Tetrahymena thermophila enables synthesis of tetrahymanol by S. cerevisiae. Moreover, expression of TtTHC1 enabled exponential growth of anaerobic S. cerevisiae cultures in sterol-free synthetic media. After deletion of the ERG1 gene from a TtTHC1-expressing S. cerevisiae strain, native sterol synthesis was abolished and sustained sterol-free growth was demonstrated under anaerobic as well as aerobic conditions. Anaerobic cultures of TtTHC1-expressing S. cerevisiae on sterol-free medium showed lower specific growth rates and biomass yields than ergosterol-supplemented cultures, while their ethanol yield was higher. This study demonstrated that acquisition of a functional squalene-tetrahymanol cyclase gene offers an immediate growth advantage to S. cerevisiae under anaerobic, sterol-limited conditions and provides the basis for a metabolic engineering strategy to eliminate the oxygen requirements associated with sterol synthesis in yeasts. IMPORTANCE The laboratory experiments described in this report simulate a proposed horizontal gene transfer event during the evolution of strictly anaerobic fungi. The demonstration that expression of a single heterologous gene sufficed to eliminate anaerobic sterol requirements in the model eukaryote Saccharomyces cerevisiae therefore contributes to our understanding of how sterol-independent eukaryotes evolved in anoxic environments. This report provides a proof of principle for a metabolic engineering strategy to eliminate sterol requirements in yeast strains that are applied in large-scale anaerobic industrial processes. The sterol-independent yeast strains described in this report provide a valuable platform for further studies on the physiological roles and impacts of sterols and sterol surrogates in eukaryotic cells.
Collapse
|
13
|
Welander PV. Deciphering the evolutionary history of microbial cyclic triterpenoids. Free Radic Biol Med 2019; 140:270-278. [PMID: 31071437 DOI: 10.1016/j.freeradbiomed.2019.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 05/02/2019] [Accepted: 05/02/2019] [Indexed: 11/26/2022]
Abstract
Cyclic triterpenoids are a class of lipids that have fascinated chemists, biologist, and geologist alike for many years. These molecules have diverse physiological roles in a variety of bacterial and eukaryotic organisms and a shared evolutionary ancestry that is reflected in the elegant biochemistry required for their synthesis. Cyclic triterpenoids are also quite recalcitrant and are preserved in sedimentary rocks where they are utilized as "molecular fossils" or biomarkers that can physically link microbial taxa and their metabolisms to a specific time or event in Earth's history. However, a proper interpretation of cyclic triterpenoid biosignatures requires a robust understanding of their function in extant organisms and in the evolutionary history of their biosynthetic pathways. Here, I review two potential cyclic triterpenoid evolutionary scenarios and the recent genetic and biochemical studies that are providing experimental evidence to distinguish between these hypotheses. The study of cyclic triterpenoids will continue to provide a wealth of information that can significantly impact the interpretation of lipid biosignatures in the rock record and provides a compelling model of how two natural repositories of evolutionary history available on Earth, the geologic record in sedimentary rocks and the molecular record in living organisms, can be linked.
Collapse
Affiliation(s)
- Paula V Welander
- Department of Earth System Science, Stanford University, 473 Via Ortega, Rm 140, Stanford, CA, 94305, USA.
| |
Collapse
|
14
|
Olivera ER, Luengo JM. Steroids as Environmental Compounds Recalcitrant to Degradation: Genetic Mechanisms of Bacterial Biodegradation Pathways. Genes (Basel) 2019; 10:E512. [PMID: 31284586 PMCID: PMC6678751 DOI: 10.3390/genes10070512] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 07/02/2019] [Accepted: 07/03/2019] [Indexed: 12/29/2022] Open
Abstract
Steroids are perhydro-1,2-cyclopentanophenanthrene derivatives that are almost exclusively synthesised by eukaryotic organisms. Since the start of the Anthropocene, the presence of these molecules, as well as related synthetic compounds (ethinylestradiol, dexamethasone, and others), has increased in different habitats due to farm and municipal effluents and discharge from the pharmaceutical industry. In addition, the highly hydrophobic nature of these molecules, as well as the absence of functional groups, makes them highly resistant to biodegradation. However, some environmental bacteria are able to modify or mineralise these compounds. Although steroid-metabolising bacteria have been isolated since the beginning of the 20th century, the genetics and catabolic pathways used have only been characterised in model organisms in the last few decades. Here, the metabolic alternatives used by different bacteria to metabolise steroids (e.g., cholesterol, bile acids, testosterone, and other steroid hormones), as well as the organisation and conservation of the genes involved, are reviewed.
Collapse
Affiliation(s)
- Elías R Olivera
- Departamento Biología Molecular (Área Bioquímica y Biología Molecular), Universidad de León, 24007 León, Spain.
| | - José M Luengo
- Departamento Biología Molecular (Área Bioquímica y Biología Molecular), Universidad de León, 24007 León, Spain
| |
Collapse
|
15
|
Gudde LR, Hulce M, Largen AH, Franke JD. Sterol synthesis is essential for viability in the planctomycete bacterium Gemmata obscuriglobus. FEMS Microbiol Lett 2019; 366:5304612. [DOI: 10.1093/femsle/fnz019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 01/29/2019] [Indexed: 12/11/2022] Open
Affiliation(s)
- Luke R Gudde
- Department of Biology, Creighton University, Hixson-Leid Science Building Room 403, 2500 California Plaza, Omaha, NE 68178, USA
| | - Martin Hulce
- Department of Chemistry, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA
| | - Alexander H Largen
- Department of Biology, Creighton University, Hixson-Leid Science Building Room 403, 2500 California Plaza, Omaha, NE 68178, USA
| | - Josef D Franke
- Department of Biology, Creighton University, Hixson-Leid Science Building Room 403, 2500 California Plaza, Omaha, NE 68178, USA
| |
Collapse
|
16
|
Anoxic ecosystems and early eukaryotes. Emerg Top Life Sci 2018; 2:299-309. [DOI: 10.1042/etls20170162] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 05/22/2018] [Accepted: 05/24/2018] [Indexed: 01/27/2023]
Abstract
Through much of the Proterozoic Eon (2.5–0.54 billion years ago, Ga), oceans were dominantly anoxic. It is often assumed that this put a brake on early eukaryote diversification because eukaryotes lived only in oxygenated habitats, which were restricted to surface waters and benthic environments near cyanobacterial mats. Studies of extant microbial eukaryotes show, however, that they are diverse and abundant in anoxic (including sulfidic) environments, often through partnerships with endo- and ectosymbiotic bacteria and archaea. Though the last common ancestor of extant eukaryotes was capable of aerobic respiration, we propose that at least some, and perhaps many, early eukaryotes were adapted to anoxic settings, and outline a way to test this with the microfossil and redox-proxy record in Proterozoic shales. This hypothesis might explain the mismatch between the record of eukaryotic body fossils, which extends back to >1.6 Ga, and the record of sterane biomarkers, which become diverse and abundant only after 659 Ma, as modern eukaryotes adapted to anoxic habitats do not make sterols (sterane precursors). In addition, an anoxic habitat might make sense for several long-ranging (>800 million years) and globally widespread eukaryotic taxa, which disappear in the late Neoproterozoic around the time oxic environments are thought to have become more widespread.
Collapse
|
17
|
Belin BJ, Busset N, Giraud E, Molinaro A, Silipo A, Newman DK. Hopanoid lipids: from membranes to plant-bacteria interactions. Nat Rev Microbiol 2018; 16:304-315. [PMID: 29456243 PMCID: PMC6087623 DOI: 10.1038/nrmicro.2017.173] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Lipid research represents a frontier for microbiology, as showcased by hopanoid lipids. Hopanoids, which resemble sterols and are found in the membranes of diverse bacteria, have left an extensive molecular fossil record. They were first discovered by petroleum geologists. Today, hopanoid-producing bacteria remain abundant in various ecosystems, such as the rhizosphere. Recently, great progress has been made in our understanding of hopanoid biosynthesis, facilitated in part by technical advances in lipid identification and quantification. A variety of genetically tractable, hopanoid-producing bacteria have been cultured, and tools to manipulate hopanoid biosynthesis and detect hopanoids are improving. However, we still have much to learn regarding how hopanoid production is regulated, how hopanoids act biophysically and biochemically, and how their production affects bacterial interactions with other organisms, such as plants. The study of hopanoids thus offers rich opportunities for discovery.
Collapse
Affiliation(s)
- Brittany J. Belin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Nicolas Busset
- Institut de Recherche pour le Développement, LSTM, UMR IRD, SupAgro, INRA, University of Montpellier, CIRAD, France
| | - Eric Giraud
- Institut de Recherche pour le Développement, LSTM, UMR IRD, SupAgro, INRA, University of Montpellier, CIRAD, France
| | - Antonio Molinaro
- Department of Chemical Sciences, University of Naples Federico II, Napoli, Italy
| | - Alba Silipo
- Department of Chemical Sciences, University of Naples Federico II, Napoli, Italy
| | - Dianne K. Newman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| |
Collapse
|
18
|
Methane utilization in Methylomicrobium alcaliphilum 20Z R: a systems approach. Sci Rep 2018; 8:2512. [PMID: 29410419 PMCID: PMC5802761 DOI: 10.1038/s41598-018-20574-z] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 01/22/2018] [Indexed: 12/20/2022] Open
Abstract
Biological methane utilization, one of the main sinks of the greenhouse gas in nature, represents an attractive platform for production of fuels and value-added chemicals. Despite the progress made in our understanding of the individual parts of methane utilization, our knowledge of how the whole-cell metabolic network is organized and coordinated is limited. Attractive growth and methane-conversion rates, a complete and expert-annotated genome sequence, as well as large enzymatic, 13C-labeling, and transcriptomic datasets make Methylomicrobium alcaliphilum 20ZR an exceptional model system for investigating methane utilization networks. Here we present a comprehensive metabolic framework of methane and methanol utilization in M. alcaliphilum 20ZR. A set of novel metabolic reactions governing carbon distribution across central pathways in methanotrophic bacteria was predicted by in-silico simulations and confirmed by global non-targeted metabolomics and enzymatic evidences. Our data highlight the importance of substitution of ATP-linked steps with PPi-dependent reactions and support the presence of a carbon shunt from acetyl-CoA to the pentose-phosphate pathway and highly branched TCA cycle. The diverged TCA reactions promote balance between anabolic reactions and redox demands. The computational framework of C1-metabolism in methanotrophic bacteria can represent an efficient tool for metabolic engineering or ecosystem modeling.
Collapse
|
19
|
Osborne KA, Gray ND, Sherry A, Leary P, Mejeha O, Bischoff J, Rush D, Sidgwick FR, Birgel D, Kalyuzhnaya MG, Talbot HM. Methanotroph-derived bacteriohopanepolyol signatures as a function of temperature related growth, survival, cell death and preservation in the geological record. ENVIRONMENTAL MICROBIOLOGY REPORTS 2017; 9:492-500. [PMID: 28772060 DOI: 10.1111/1758-2229.12570] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Accepted: 07/24/2017] [Indexed: 06/07/2023]
Abstract
Interpretation of bacteriohopanepolyol (BHP) biomarkers tracing microbiological processes in modern and ancient sediments relies on understanding environmental controls of production and preservation. BHPs from methanotrophs (35-aminoBHPs) were studied in methane-amended aerobic river-sediment incubations at different temperatures. It was found that: (i) With increasing temperature (4°C-40°C) a 10-fold increase in aminopentol (associated with Crenothrix and Methylobacter spp. growth) occurred with only marginal increases in aminotriol and aminotetrol; (ii) A further increase in temperature (50°C) saw selection for the thermophile Methylocaldum and mixtures of aminopentol and C-3 methylated aminopentol, again, with no increase in aminotriol and aminotetrol. (iii) At 30°C, more aminopentol and an aminopentol isomer and unsaturated aminopentol were produced after methanotroph growth and the onset of substrate starvation/oxygen depletion. (iv) At 50°C, aminopentol and C-3 methylated aminopentol, only accumulated during growth but were clearly resistant to remineralization despite cell death. These results have profound implications for the interpretation of aminoBHP distributions and abundances in modern and past environments. For instance, a temperature regulation of aminopentol production but not aminotetrol or aminotriol is consistent with and, corroborative of, observed aminopentol sensitivity to climate warming recorded in a stratigraphic sequence deposited during the Paleocene-Eocene thermal maximum (PETM).
Collapse
Affiliation(s)
- Kate A Osborne
- School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Neil D Gray
- School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Angela Sherry
- School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Peter Leary
- School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Obioma Mejeha
- School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Juliane Bischoff
- School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Darci Rush
- School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
- Department of Microbiology & Biogeochemistry, The Royal Netherlands Institute for Sea Research (NIOZ), Den Hag, Texel, The Netherlands
| | - Frances R Sidgwick
- School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
- Newcastle University Protein and Proteome Analysis (NUPPA), Devonshire Building, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Daniel Birgel
- Institute for Geology, Universität Hamburg, Bundesstraße 55, Hamburg 20146, Germany
| | | | - Helen M Talbot
- School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| |
Collapse
|
20
|
Bradley AS, Swanson PK, Muller EEL, Bringel F, Caroll SM, Pearson A, Vuilleumier S, Marx CJ. Hopanoid-free Methylobacterium extorquens DM4 overproduces carotenoids and has widespread growth impairment. PLoS One 2017; 12:e0173323. [PMID: 28319163 PMCID: PMC5358736 DOI: 10.1371/journal.pone.0173323] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 02/17/2017] [Indexed: 01/27/2023] Open
Abstract
Hopanoids are sterol-like membrane lipids widely used as geochemical proxies for bacteria. Currently, the physiological role of hopanoids is not well understood, and this represents one of the major limitations in interpreting the significance of their presence in ancient or contemporary sediments. Previous analyses of mutants lacking hopanoids in a range of bacteria have revealed a range of phenotypes under normal growth conditions, but with most having at least an increased sensitivity to toxins and osmotic stress. We employed hopanoid-free strains of Methylobacterium extorquens DM4, uncovering severe growth defects relative to the wild-type under many tested conditions, including normal growth conditions without additional stressors. Mutants overproduce carotenoids-the other major isoprenoid product of this strain-and show an altered fatty acid profile, pronounced flocculation in liquid media, and lower growth yields than for the wild-type strain. The flocculation phenotype can be mitigated by addition of cellulase to the medium, suggesting a link between the function of hopanoids and the secretion of cellulose in M. extorquens DM4. On solid media, colonies of the hopanoid-free mutant strain were smaller than wild-type, and were more sensitive to osmotic or pH stress, as well as to a variety of toxins. The results for M. extorquens DM4 are consistent with the hypothesis that hopanoids are important for membrane fluidity and lipid packing, but also indicate that the specific physiological processes that require hopanoids vary across bacterial lineages. Our work provides further support to emerging observations that the role of hopanoids in membrane robustness and barrier function may be important across lineages, possibly mediated through an interaction with lipid A in the outer membrane.
Collapse
Affiliation(s)
- Alexander S. Bradley
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, United States of America
- Department of Earth and Planetary Sciences, Washington University in St Louis, St Louis, MO, United States of America
| | - Paige K. Swanson
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, United States of America
| | - Emilie E. L. Muller
- Equipe Adaptations et interactions microbiennes, Université de Strasbourg, UMR 7156 UNISTRA–CNRS Génétique Moléculaire, Génomique, Microbiologie, Strasbourg, France
| | - Françoise Bringel
- Equipe Adaptations et interactions microbiennes, Université de Strasbourg, UMR 7156 UNISTRA–CNRS Génétique Moléculaire, Génomique, Microbiologie, Strasbourg, France
| | - Sean M. Caroll
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, United States of America
| | - Ann Pearson
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, United States of America
| | - Stéphane Vuilleumier
- Equipe Adaptations et interactions microbiennes, Université de Strasbourg, UMR 7156 UNISTRA–CNRS Génétique Moléculaire, Génomique, Microbiologie, Strasbourg, France
| | - Christopher J. Marx
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, United States of America
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States of America
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, ID, United States of America
- Center for Modeling Complex Interactions, University of Idaho, Moscow, ID, United States of America
| |
Collapse
|
21
|
Paleoproterozoic sterol biosynthesis and the rise of oxygen. Nature 2017; 543:420-423. [PMID: 28264195 DOI: 10.1038/nature21412] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 01/19/2017] [Indexed: 01/15/2023]
Abstract
Natural products preserved in the geological record can function as 'molecular fossils', providing insight into organisms and physiologies that existed in the deep past. One important group of molecular fossils is the steroidal hydrocarbons (steranes), which are the diagenetic remains of sterol lipids. Complex sterols with modified side chains are unique to eukaryotes, although simpler sterols can also be synthesized by a few bacteria. Sterol biosynthesis is an oxygen-intensive process; thus, the presence of complex steranes in ancient rocks not only signals the presence of eukaryotes, but also aerobic metabolic processes. In 1999, steranes were reported in 2.7 billion year (Gyr)-old rocks from the Pilbara Craton in Australia, suggesting a long delay between photosynthetic oxygen production and its accumulation in the atmosphere (also known as the Great Oxidation Event) 2.45-2.32 Gyr ago. However, the recent reappraisal and rejection of these steranes as contaminants pushes the oldest reported steranes forward to around 1.64 Gyr ago (ref. 6). Here we use a molecular clock approach to improve constraints on the evolution of sterol biosynthesis. We infer that stem eukaryotes shared functionally modern sterol biosynthesis genes with bacteria via horizontal gene transfer. Comparing multiple molecular clock analyses, we find that the maximum marginal probability for the divergence time of bacterial and eukaryal sterol biosynthesis genes is around 2.31 Gyr ago, concurrent with the most recent geochemical evidence for the Great Oxidation Event. Our results therefore indicate that simple sterol biosynthesis existed well before the diversification of living eukaryotes, substantially predating the oldest detected sterane biomarkers (approximately 1.64 Gyr ago), and furthermore, that the evolutionary history of sterol biosynthesis is tied to the first widespread availability of molecular oxygen in the ocean-atmosphere system.
Collapse
|
22
|
Banta AB, Wei JH, Gill CCC, Giner JL, Welander PV. Synthesis of arborane triterpenols by a bacterial oxidosqualene cyclase. Proc Natl Acad Sci U S A 2017; 114:245-250. [PMID: 28028245 PMCID: PMC5240688 DOI: 10.1073/pnas.1617231114] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Cyclic triterpenoids are a broad class of polycyclic lipids produced by bacteria and eukaryotes. They are biologically relevant for their roles in cellular physiology, including membrane structure and function, and biochemically relevant for their exquisite enzymatic cyclization mechanism. Cyclic triterpenoids are also geobiologically significant as they are readily preserved in sediments and are used as biomarkers for ancient life throughout Earth's history. Isoarborinol is one such triterpenoid whose only known biological sources are certain angiosperms and whose diagenetic derivatives (arboranes) are often used as indicators of terrestrial input into aquatic environments. However, the occurrence of arborane biomarkers in Permian and Triassic sediments, which predates the accepted origin of angiosperms, suggests that microbial sources of these lipids may also exist. In this study, we identify two isoarborinol-like lipids, eudoraenol and adriaticol, produced by the aerobic marine heterotrophic bacterium Eudoraea adriatica Phylogenetic analysis demonstrates that the E. adriatica eudoraenol synthase is an oxidosqualene cyclase homologous to bacterial lanosterol synthases and distinct from plant triterpenoid synthases. Using an Escherichia coli heterologous sterol expression system, we demonstrate that substitution of four amino acid residues in a bacterial lanosterol synthase enabled synthesis of pentacyclic arborinols in addition to tetracyclic sterols. This variant provides valuable mechanistic insight into triterpenoid synthesis and reveals diagnostic amino acid residues to differentiate between sterol and arborinol synthases in genomic and metagenomic datasets. Our data suggest that there may be additional bacterial arborinol producers in marine and freshwater environments that could expand our understanding of these geologically informative lipids.
Collapse
Affiliation(s)
- Amy B Banta
- Department of Earth System Science, Stanford University, Stanford, CA 94305
| | - Jeremy H Wei
- Department of Earth System Science, Stanford University, Stanford, CA 94305
| | - Clare C C Gill
- Department of Earth System Science, Stanford University, Stanford, CA 94305
| | - José-Luis Giner
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210
| | - Paula V Welander
- Department of Earth System Science, Stanford University, Stanford, CA 94305;
| |
Collapse
|
23
|
Rush D, Osborne KA, Birgel D, Kappler A, Hirayama H, Peckmann J, Poulton SW, Nickel JC, Mangelsdorf K, Kalyuzhnaya M, Sidgwick FR, Talbot HM. The Bacteriohopanepolyol Inventory of Novel Aerobic Methane Oxidising Bacteria Reveals New Biomarker Signatures of Aerobic Methanotrophy in Marine Systems. PLoS One 2016; 11:e0165635. [PMID: 27824887 PMCID: PMC5100885 DOI: 10.1371/journal.pone.0165635] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 10/15/2016] [Indexed: 12/24/2022] Open
Abstract
Aerobic methane oxidation (AMO) is one of the primary biologic pathways regulating the amount of methane (CH4) released into the environment. AMO acts as a sink of CH4, converting it into carbon dioxide before it reaches the atmosphere. It is of interest for (paleo)climate and carbon cycling studies to identify lipid biomarkers that can be used to trace AMO events, especially at times when the role of methane in the carbon cycle was more pronounced than today. AMO bacteria are known to synthesise bacteriohopanepolyol (BHP) lipids. Preliminary evidence pointed towards 35-aminobacteriohopane-30,31,32,33,34-pentol (aminopentol) being a characteristic biomarker for Type I methanotrophs. Here, the BHP compositions were examined for species of the recently described novel Type I methanotroph bacterial genera Methylomarinum and Methylomarinovum, as well as for a novel species of a Type I Methylomicrobium. Aminopentol was the most abundant BHP only in Methylomarinovum caldicuralii, while Methylomicrobium did not produce aminopentol at all. In addition to the expected regular aminotriol and aminotetrol BHPs, novel structures tentatively identified as methylcarbamate lipids related to C-35 amino-BHPs (MC-BHPs) were found to be synthesised in significant amounts by some AMO cultures. Subsequently, sediments and authigenic carbonates from methane-influenced marine environments were analysed. Most samples also did not contain significant amounts of aminopentol, indicating that aminopentol is not a useful biomarker for marine aerobic methanotophic bacteria. However, the BHP composition of the marine samples do point toward the novel MC-BHPs components being potential new biomarkers for AMO.
Collapse
Affiliation(s)
- Darci Rush
- School of Civil Engineering & Geosciences, Newcastle University, Drummond Building, Newcastle upon Tyne, NE1 7RU, Newcastle-upon-Tyne, United Kingdom
- * E-mail:
| | - Kate A. Osborne
- School of Civil Engineering & Geosciences, Newcastle University, Drummond Building, Newcastle upon Tyne, NE1 7RU, Newcastle-upon-Tyne, United Kingdom
| | - Daniel Birgel
- Institute of Geology, University of Hamburg, Hamburg, Germany
| | - Andreas Kappler
- Center for Applied Geoscience, University of Tübingen, Tübingen, Germany
- Center for Geomicrobiology, Department of Bioscience, Ny Munkegade 116, 8000, Aarhus C, Denmark
| | - Hisako Hirayama
- Department of Subsurface Geobiological Analysis and Research, Japan Agency for Marine-Earth Science & Technology (JAMSTEC), Yokosuka, Japan
| | - Jörn Peckmann
- Institute of Geology, University of Hamburg, Hamburg, Germany
- Department of Geodynamics and Sedimentology, University of Vienna, 1090, Vienna, Austria
| | - Simon W. Poulton
- School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Julia C. Nickel
- GFZ German Research Centre for Geosciences, Telegrafenberg, D-14473, Potsdam, Germany
| | - Kai Mangelsdorf
- GFZ German Research Centre for Geosciences, Telegrafenberg, D-14473, Potsdam, Germany
| | - Marina Kalyuzhnaya
- Faculty of Biology, San Diego State University, 5500 Campanile Drive, San Diego, 92182, United States of America
| | - Frances R. Sidgwick
- School of Civil Engineering & Geosciences, Newcastle University, Drummond Building, Newcastle upon Tyne, NE1 7RU, Newcastle-upon-Tyne, United Kingdom
| | - Helen M. Talbot
- School of Civil Engineering & Geosciences, Newcastle University, Drummond Building, Newcastle upon Tyne, NE1 7RU, Newcastle-upon-Tyne, United Kingdom
| |
Collapse
|
24
|
Schmidt NG, Eger E, Kroutil W. Building Bridges: Biocatalytic C-C-Bond Formation toward Multifunctional Products. ACS Catal 2016; 6:4286-4311. [PMID: 27398261 PMCID: PMC4936090 DOI: 10.1021/acscatal.6b00758] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 05/13/2016] [Indexed: 12/12/2022]
Abstract
Carbon-carbon bond formation is the key reaction for organic synthesis to construct the carbon framework of organic molecules. The review gives a selection of biocatalytic C-C-bond-forming reactions which have been investigated during the last 5 years and which have already been proven to be applicable for organic synthesis. In most cases, the reactions lead to products functionalized at the site of C-C-bond formation (e.g., α-hydroxy ketones, aminoalcohols, diols, 1,4-diketones, etc.) or allow to decorate aromatic and heteroaromatic molecules. Furthermore, examples for cyclization of (non)natural precursors leading to saturated carbocycles are given as well as the stereoselective cyclopropanation of olefins affording cyclopropanes. Although many tools are already available, recent research also makes it clear that nature provides an even broader set of enzymes to perform specific C-C coupling reactions. The possibilities are without limit; however, a big library of variants for different types of reactions is required to have the specific enzyme for a desired specific (stereoselective) reaction at hand.
Collapse
Affiliation(s)
- Nina G. Schmidt
- ACIB
GmbH c/o, Department of Chemistry, University
of Graz, Heinrichstrasse
28, 8010 Graz, Austria
| | - Elisabeth Eger
- Department
of Chemistry, Organic and Bioorganic Chemistry, University of Graz, NAWI Graz, Heinrichstrasse 28, 8010 Graz, Austria
| | - Wolfgang Kroutil
- ACIB
GmbH c/o, Department of Chemistry, University
of Graz, Heinrichstrasse
28, 8010 Graz, Austria
- Department
of Chemistry, Organic and Bioorganic Chemistry, University of Graz, NAWI Graz, Heinrichstrasse 28, 8010 Graz, Austria
| |
Collapse
|
25
|
Wei JH, Yin X, Welander PV. Sterol Synthesis in Diverse Bacteria. Front Microbiol 2016; 7:990. [PMID: 27446030 PMCID: PMC4919349 DOI: 10.3389/fmicb.2016.00990] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 06/09/2016] [Indexed: 11/13/2022] Open
Abstract
Sterols are essential components of eukaryotic cells whose biosynthesis and function has been studied extensively. Sterols are also recognized as the diagenetic precursors of steranes preserved in sedimentary rocks where they can function as geological proxies for eukaryotic organisms and/or aerobic metabolisms and environments. However, production of these lipids is not restricted to the eukaryotic domain as a few bacterial species also synthesize sterols. Phylogenomic studies have identified genes encoding homologs of sterol biosynthesis proteins in the genomes of several additional species, indicating that sterol production may be more widespread in the bacterial domain than previously thought. Although the occurrence of sterol synthesis genes in a genome indicates the potential for sterol production, it provides neither conclusive evidence of sterol synthesis nor information about the composition and abundance of basic and modified sterols that are actually being produced. Here, we coupled bioinformatics with lipid analyses to investigate the scope of bacterial sterol production. We identified oxidosqualene cyclase (Osc), which catalyzes the initial cyclization of oxidosqualene to the basic sterol structure, in 34 bacterial genomes from five phyla (Bacteroidetes, Cyanobacteria, Planctomycetes, Proteobacteria, and Verrucomicrobia) and in 176 metagenomes. Our data indicate that bacterial sterol synthesis likely occurs in diverse organisms and environments and also provides evidence that there are as yet uncultured groups of bacterial sterol producers. Phylogenetic analysis of bacterial and eukaryotic Osc sequences confirmed a complex evolutionary history of sterol synthesis in this domain. Finally, we characterized the lipids produced by Osc-containing bacteria and found that we could generally predict the ability to synthesize sterols. However, predicting the final modified sterol based on our current knowledge of sterol synthesis was difficult. Some bacteria produced demethylated and saturated sterol products even though they lacked homologs of the eukaryotic proteins required for these modifications emphasizing that several aspects of bacterial sterol synthesis are still completely unknown.
Collapse
Affiliation(s)
| | | | - Paula V. Welander
- Department of Earth System Science, Stanford UniversityStanford, CA, USA
| |
Collapse
|