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Parrell D, Olson J, Lemke RA, Donohue TJ, Wright ER. Quantitative Analysis of Rhodobacter sphaeroides Storage Organelles via Cryo-Electron Tomography and Light Microscopy. Biomolecules 2024; 14:1006. [PMID: 39199393 PMCID: PMC11352279 DOI: 10.3390/biom14081006] [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: 06/12/2024] [Revised: 08/05/2024] [Accepted: 08/06/2024] [Indexed: 09/01/2024] Open
Abstract
Bacterial cytoplasmic organelles are diverse and serve many varied purposes. Here, we employed Rhodobacter sphaeroides to investigate the accumulation of carbon and inorganic phosphate in the storage organelles, polyhydroxybutyrate (PHB) and polyphosphate (PP), respectively. Using cryo-electron tomography (cryo-ET), these organelles were observed to increase in size and abundance when growth was arrested by chloramphenicol treatment. The accumulation of PHB and PP was quantified from three-dimensional (3D) segmentations in cryo-tomograms and the analysis of these 3D models. The quantification of PHB using both segmentation analysis and liquid chromatography and mass spectrometry (LCMS) each demonstrated an over 10- to 20-fold accumulation of PHB. The cytoplasmic location of PHB in cells was assessed with fluorescence light microscopy using a PhaP-mNeonGreen fusion-protein construct. The subcellular location and enumeration of these organelles were correlated by comparing the cryo-ET and fluorescence microscopy data. A potential link between PHB and PP localization and possible explanations for co-localization are discussed. Finally, the study of PHB and PP granules, and their accumulation, is discussed in the context of advancing fundamental knowledge about bacterial stress response, the study of renewable sources of bioplastics, and highly energetic compounds.
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Affiliation(s)
- Daniel Parrell
- Department of Biochemistry, University of Wisconsin—Madison, Madison, WI 53706, USA; (D.P.); (J.O.)
- Wisconsin Energy Institute, University of Wisconsin—Madison, Madison, WI 53726, USA;
- Great Lakes Bioenergy Research Center, University of Wisconsin—Madison, Madison, WI 53726, USA
| | - Joseph Olson
- Department of Biochemistry, University of Wisconsin—Madison, Madison, WI 53706, USA; (D.P.); (J.O.)
| | - Rachelle A. Lemke
- Wisconsin Energy Institute, University of Wisconsin—Madison, Madison, WI 53726, USA;
- Great Lakes Bioenergy Research Center, University of Wisconsin—Madison, Madison, WI 53726, USA
| | - Timothy J. Donohue
- Wisconsin Energy Institute, University of Wisconsin—Madison, Madison, WI 53726, USA;
- Great Lakes Bioenergy Research Center, University of Wisconsin—Madison, Madison, WI 53726, USA
- Department of Bacteriology, University of Wisconsin—Madison, Madison, WI 53706, USA
| | - Elizabeth R. Wright
- Department of Biochemistry, University of Wisconsin—Madison, Madison, WI 53706, USA; (D.P.); (J.O.)
- Wisconsin Energy Institute, University of Wisconsin—Madison, Madison, WI 53726, USA;
- Great Lakes Bioenergy Research Center, University of Wisconsin—Madison, Madison, WI 53726, USA
- Cryo-Electron Microscopy Research Center, Department of Biochemistry, University of Wisconsin—Madison, Madison, WI 53706, USA
- Midwest Center for Cryo-Electron Tomography, Department of Biochemistry, University of Wisconsin—Madison, Madison, WI 53706, USA
- Morgridge Institute for Research, Madison, WI 53715, USA
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2
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Schoeppe R, Waldmann M, Jessen HJ, Renné T. An Update on Polyphosphate In Vivo Activities. Biomolecules 2024; 14:937. [PMID: 39199325 PMCID: PMC11352482 DOI: 10.3390/biom14080937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Revised: 07/13/2024] [Accepted: 07/16/2024] [Indexed: 09/01/2024] Open
Abstract
Polyphosphate (polyP) is an evolutionary ancient inorganic molecule widespread in biology, exerting a broad range of biological activities. The intracellular polymer serves as an energy storage pool and phosphate/calcium ion reservoir with implications for basal cellular functions. Metabolisms of the polymer are well understood in procaryotes and unicellular eukaryotic cells. However, functions, regulation, and association with disease states of the polymer in higher eukaryotic species such as mammalians are just beginning to emerge. The review summarises our current understanding of polyP metabolism, the polymer's functions, and methods for polyP analysis. In-depth knowledge of the pathways that control polyP turnover will open future perspectives for selective targeting of the polymer.
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Affiliation(s)
- Robert Schoeppe
- Institute of Clinical Chemistry and Laboratory Medicine (O26), University Medical Center Hamburg-Eppendorf, D-20246 Hamburg, Germany
| | - Moritz Waldmann
- Institute of Clinical Chemistry and Laboratory Medicine (O26), University Medical Center Hamburg-Eppendorf, D-20246 Hamburg, Germany
| | - Henning J. Jessen
- Institute of Organic Chemistry, Albert-Ludwigs-University of Freiburg, D-79105 Freiburg, Germany;
| | - Thomas Renné
- Institute of Clinical Chemistry and Laboratory Medicine (O26), University Medical Center Hamburg-Eppendorf, D-20246 Hamburg, Germany
- Irish Centre for Vascular Biology, School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, D02 YN77 Dublin, Ireland
- Center for Thrombosis and Haemostasis (CTH), Johannes Gutenberg University Medical Center, D-55131 Mainz, Germany
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3
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Wuo MG, Dulberger CL, Warner TC, Brown RA, Sturm A, Ultee E, Bloom-Ackermann Z, Choi C, Zhu J, Garner EC, Briegel A, Hung DT, Rubin EJ, Kiessling LL. Fluorogenic Probes of the Mycobacterial Membrane as Reporters of Antibiotic Action. J Am Chem Soc 2024; 146:17669-17678. [PMID: 38905328 DOI: 10.1021/jacs.4c00617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/23/2024]
Abstract
The genus Mycobacterium includes species such as Mycobacterium tuberculosis, which can cause deadly human diseases. These bacteria have a protective cell envelope that can be remodeled to facilitate their survival in challenging conditions. Understanding how such conditions affect membrane remodeling can facilitate antibiotic discovery and treatment. To this end, we describe an optimized fluorogenic probe, N-QTF, that reports on mycolyltransferase activity, which is vital for cell division and remodeling. N-QTF is a glycolipid probe that can reveal dynamic changes in the mycobacterial cell envelope in both fast- and slow-growing mycobacterial species. Using this probe to monitor the consequences of antibiotic treatment uncovered distinct cellular phenotypes. Even antibiotics that do not directly inhibit cell envelope biosynthesis cause conspicuous phenotypes. For instance, mycobacteria exposed to the RNA polymerase inhibitor rifampicin release fluorescent extracellular vesicles (EVs). While all mycobacteria release EVs, fluorescent EVs were detected only in the presence of RIF, indicating that exposure to the drug alters EV content. Macrophages exposed to the EVs derived from RIF-treated cells released lower levels of cytokines, suggesting the EVs moderate immune responses. These data suggest that antibiotics can alter EV content to impact immunity. Our ability to see such changes in EV constituents directly results from exploiting these chemical probes.
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Affiliation(s)
- Michael G Wuo
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue Cambridge, Cambridge, Massachusetts 02139, United States
| | - Charles L Dulberger
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 677 Huntington Ave, Boston, Massachusetts 02115, United States
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford St, Cambridge, Massachusetts 02138, United States
| | - Theodore C Warner
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue Cambridge, Cambridge, Massachusetts 02139, United States
| | - Robert A Brown
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Alexander Sturm
- Broad Institute of MIT and Harvard, 415 Main St, Cambridge, Massachusetts 02142, United States
| | - Eveline Ultee
- Institute of Biology, Leiden University, Rapenburg 70, 2311 EZ Leiden, The Netherlands
| | - Zohar Bloom-Ackermann
- Broad Institute of MIT and Harvard, 415 Main St, Cambridge, Massachusetts 02142, United States
| | - Catherine Choi
- Broad Institute of MIT and Harvard, 415 Main St, Cambridge, Massachusetts 02142, United States
| | - Junhao Zhu
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 677 Huntington Ave, Boston, Massachusetts 02115, United States
| | - Ethan C Garner
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford St, Cambridge, Massachusetts 02138, United States
| | - Ariane Briegel
- Institute of Biology, Leiden University, Rapenburg 70, 2311 EZ Leiden, The Netherlands
| | - Deborah T Hung
- Broad Institute of MIT and Harvard, 415 Main St, Cambridge, Massachusetts 02142, United States
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 55 Fruit Street, Boston, Massachusetts 02114, United States
- Department of Genetics, Harvard Medical School, 25 Shattuck Street, Boston, Massachusetts 02115, United States
| | - Eric J Rubin
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 677 Huntington Ave, Boston, Massachusetts 02115, United States
| | - Laura L Kiessling
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue Cambridge, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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Kahil K, Kaplan-Ashiri I, Wolf SG, Rechav K, Weiner S, Addadi L. Elemental compositions of sea urchin larval cell vesicles evaluated by cryo-STEM-EDS and cryo-SEM-EDS. Acta Biomater 2023; 155:482-490. [PMID: 36375785 DOI: 10.1016/j.actbio.2022.11.012] [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: 07/14/2022] [Revised: 11/03/2022] [Accepted: 11/04/2022] [Indexed: 11/15/2022]
Abstract
During spicule formation in sea urchin larvae, calcium ions translocate within the primary mesenchymal cells (PMCs) from endocytosed seawater vacuoles to various organelles and vesicles where they accumulate, and subsequently precipitate. During this process, calcium ions are concentrated by more than three orders of magnitude, while other abundant ions (Na, Mg) must be removed. To obtain information about the overall ion composition in the vesicles, we used quantitative cryo-SEM-EDS and cryo-STEM-EDS analyzes. For cryo-STEM-EDS, thin (500 nm) frozen hydrated lamellae of PMCs were fabricated using cryo-focused ion beam-SEM. The lamellae were then loaded into a cryo-TEM, imaged and the ion composition of electron dense bodies was measured. Analyzes performed on 18 Ca-rich particles/particle clusters from 6 cells contained Ca, Na, Mg, S and P in different ratios. Surprisingly, all the Ca-rich particles contained P in amounts up to almost 1:1 of Ca. These cryo-STEM-EDS results were qualitatively confirmed by cryo-SEM-EDS analyzes of 310 vesicles, performed on high pressure frozen and cryo-planed samples. We discuss the advantages and limitations of the two techniques, and their potential applicability, especially to study ion transport pathways and ion trafficking in cells involved in mineralization. STATEMENT OF SIGNIFICANCE: The 'inorganic side of life', encompassing ion trafficking and ion storage in soft tissues of organisms, is a generally overlooked problem. Addressing such a problem becomes possible through the application of innovative techniques, performed in cryogenic conditions, which preserve the tissues in quasi-physiological state. We developed here a set of analytical tools, cryo-SEM-EDS, and cryo-STEM-EDS, which allow reconstructing the ion composition inside vesicles in sea urchin larval cells, on their way to deposit mineral in the skeletons. The techniques are complex, and we evaluate here the advantages and disadvantages of each technique. The methodologies that we are developing here can be applied to other cells and other pathways as well, eventually leading to quantitative elemental analyzes of tissues under cryogenic conditions.
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Affiliation(s)
- Keren Kahil
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ifat Kaplan-Ashiri
- Department of Chemical Research Support, Weizmann Institute, Rehovot 7610001, Israel
| | - Sharon G Wolf
- Department of Chemical Research Support, Weizmann Institute, Rehovot 7610001, Israel
| | - Katya Rechav
- Department of Chemical Research Support, Weizmann Institute, Rehovot 7610001, Israel
| | - Steve Weiner
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel.
| | - Lia Addadi
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel.
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5
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Diaz R, Mackey B, Chadalavada S, Kainthola J, Heck P, Goel R. Enhanced Bio-P removal: Past, present, and future - A comprehensive review. CHEMOSPHERE 2022; 309:136518. [PMID: 36191763 DOI: 10.1016/j.chemosphere.2022.136518] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 09/14/2022] [Accepted: 09/15/2022] [Indexed: 06/16/2023]
Abstract
Excess amounts of phosphorus (P) and nitrogen (N) from anthropogenic activities such as population growth, municipal and industrial wastewater discharges, agriculture fertilization and storm water runoffs, have affected surface water chemistry, resulting in episodes of eutrophication. Enhanced biological phosphorus removal (EBPR) based treatment processes are an economical and environmentally friendly solution to address the present environmental impacts caused by excess P present in municipal discharges. EBPR practices have been researched and operated for more than five decades worldwide, with promising results in decreasing orthophosphate to acceptable levels. The advent of molecular tools targeting bacterial genomic deoxyribonucleic acid (DNA) has also helped us reveal the identity of potential polyphosphate-accumulating organisms (PAO) and denitrifying PAO (DPAO) responsible for the success of EBPR. Integration of process engineering and environmental microbiology has provided much-needed confidence to the wastewater community for the successful implementation of EBPR practices around the globe. Despite these successes, the process of EBPR continues to evolve in terms of its microbiology and application in light of other biological processes such as anaerobic ammonia oxidation and on-site carbon capture. This review provides an overview of the history of EBPR, discusses different operational parameters critical for the successful operation of EBPR systems, reviews current knowledge of EBPR microbiology, the influence of PAO/DPAO on the disintegration of microbial communities, stoichiometry, EBPR clades, current practices, and upcoming potential innovations.
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Affiliation(s)
- Ruby Diaz
- Department of Civil and Environmental Engineering, University of Utah, Salt Lake City, UT, 84112, USA
| | - Brendan Mackey
- Department of Civil and Environmental Engineering, University of Utah, Salt Lake City, UT, 84112, USA
| | - Sreeni Chadalavada
- School of Engineering, University of Southern Queensland Springfield, Queensland, 4350, Australia.
| | - Jyoti Kainthola
- Department of Civil Engineering, École Centrale School of Engineering, Mahindra University, Hyderabad, India, 500043
| | - Phil Heck
- Central Valley Water Reclamation Facility, Salt Lake City, UT, USA
| | - Ramesh Goel
- Department of Civil and Environmental Engineering, University of Utah, Salt Lake City, UT, 84112, USA.
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6
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Status and advances in technologies for phosphorus species detection and characterization in natural environment- A comprehensive review. Talanta 2021; 233:122458. [PMID: 34215099 DOI: 10.1016/j.talanta.2021.122458] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/19/2021] [Accepted: 04/22/2021] [Indexed: 12/30/2022]
Abstract
Poor recovery of phosphorus (P) across natural environment (water, soil, sediment, and biological sources) is causing rapid depletion of phosphate rocks and continuous accumulation of P in natural waters, resulting in deteriorated water quality and aquatic lives. Accurate detection and characterization of various P species using suitable analytical methods provide a comprehensive understanding of the biogeochemical cycle of P and thus help its proper management in the environment. This paper aims to provide a comprehensive review of the analytical methods used for P speciation in natural environment by dividing them into five broad categories (i.e., chemical, biological, molecular, staining microscopy, and sensors) and highlighting the suitability (i.e., targeted species, sample matrix), detection limit, advantages-limitations, and reference studies of all methods under each category. This can be useful in designing studies involving P detection and characterization across environmental matrices by providing insights about a wide range of analytical methods based on the end user application needs of individual studies.
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7
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Single- or double-membrane-bound vesicles and P, Ca, and Fe-containing granules in Xanthomonas citri cultured on a solid medium. Micron 2021; 143:103024. [PMID: 33549851 DOI: 10.1016/j.micron.2021.103024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 01/22/2021] [Accepted: 01/22/2021] [Indexed: 11/21/2022]
Abstract
The organelle-like structures of Xanthomonas citri, a bacterial pathogen that causes citrus canker, were investigated using an analytical transmission electron microscope. After high-pressure freezing, the bacteria were then freeze-substituted for imaging and element analysis. Miniscule electron-dense structures of varying shapes without a membrane enclosure were frequently observed near the cell poles in a 3-day culture. The bacteria formed cytoplasmic electron-dense spherical structures measuring approximately 50 nm in diameter. Furthermore, X. citri produced electron-dense or translucent ellipsoidal intracellular or extracellular granules. Single- or double-membrane-bound vesicles, including outer-inner membrane vesicles, were observed both inside and outside the cells. Most cells had been lysed in the 3-week X. citri culture, but they harbored one or two electron-dense spherical structures. Contrast-inverted scanning transmission electron microscopy images revealed distinct white spherical structures within the cytoplasm of X. citri. Likewise, energy-dispersive X-ray spectrometry showed the spatial heterogeneity and co-localization of phosphorus, oxygen, calcium, and iron only in the cytoplasmic electron-dense spherical structures, thus corroborating the nature of polyphosphate granules.
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8
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Loukanov A, Mladenova P, Toshev S, Udono H, Nakabayashi S. Visualization of the native shape of bodipy-labeled DNA in Escherichia coli
by correlative microscopy. Microsc Res Tech 2017; 81:267-274. [DOI: 10.1002/jemt.22975] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 11/13/2017] [Accepted: 11/14/2017] [Indexed: 11/07/2022]
Affiliation(s)
- Alexandre Loukanov
- Graduate School of Science and Engineering; Saitama University; Shimo-Ohkubo 255, Sakura-Ku Saitama, 338-8570 Japan
- Laboratory of Eng. NanoBiotechnology, Department of Engineering Geoecology; University of Mining and Geology “St. Ivan Rilski”; Sofia, 1700 Bulgaria
| | - Polina Mladenova
- Laboratory of Eng. NanoBiotechnology, Department of Engineering Geoecology; University of Mining and Geology “St. Ivan Rilski”; Sofia, 1700 Bulgaria
| | - Svetlin Toshev
- Laboratory of Eng. NanoBiotechnology, Department of Engineering Geoecology; University of Mining and Geology “St. Ivan Rilski”; Sofia, 1700 Bulgaria
| | - Hibiki Udono
- Graduate School of Science and Engineering; Saitama University; Shimo-Ohkubo 255, Sakura-Ku Saitama, 338-8570 Japan
| | - Seiichiro Nakabayashi
- Graduate School of Science and Engineering; Saitama University; Shimo-Ohkubo 255, Sakura-Ku Saitama, 338-8570 Japan
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Ultrastructure of compacted DNA in cyanobacteria by high-voltage cryo-electron tomography. Sci Rep 2016; 6:34934. [PMID: 27731339 PMCID: PMC5059737 DOI: 10.1038/srep34934] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 09/20/2016] [Indexed: 01/15/2023] Open
Abstract
Some cyanobacteria exhibit compaction of DNA in synchrony with their circadian rhythms accompanying cell division. Since the structure is transient, it has not yet been described in detail. Here, we successfully visualize the ultrastructure of compacted DNA in the cyanobacterium Synechococcus elongatus PCC 7942 under rigorous synchronized cultivation by means of high-voltage cryo-electron tomography. In 3D reconstructions of rapidly frozen cells, the compacted DNA appears as an undulating rod resembling a eukaryotic condensed chromosome. The compacted DNA also includes many small and paired polyphosphate bodies (PPBs), some of which seem to maintain contact with DNA that appears to twist away from them, indicating that they may act as interactive suppliers and regulators of phosphate for DNA synthesis. These observations throw light on the duplication and segregation mechanisms of cyanobacterial DNA and point to an important role for PPBs.
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Tarayre C, Nguyen HT, Brognaux A, Delepierre A, De Clercq L, Charlier R, Michels E, Meers E, Delvigne F. Characterisation of Phosphate Accumulating Organisms and Techniques for Polyphosphate Detection: A Review. SENSORS (BASEL, SWITZERLAND) 2016; 16:E797. [PMID: 27258275 PMCID: PMC4934223 DOI: 10.3390/s16060797] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 05/19/2016] [Accepted: 05/26/2016] [Indexed: 11/16/2022]
Abstract
Phosphate minerals have long been used for the production of phosphorus-based chemicals used in many economic sectors. However, these resources are not renewable and the natural phosphate stocks are decreasing. In this context, the research of new phosphate sources has become necessary. Many types of wastes contain non-negligible phosphate concentrations, such as wastewater. In wastewater treatment plants, phosphorus is eliminated by physicochemical and/or biological techniques. In this latter case, a specific microbiota, phosphate accumulating organisms (PAOs), accumulates phosphate as polyphosphate. This molecule can be considered as an alternative phosphate source, and is directly extracted from wastewater generated by human activities. This review focuses on the techniques which can be applied to enrich and try to isolate these PAOs, and to detect the presence of polyphosphate in microbial cells.
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Affiliation(s)
- Cédric Tarayre
- Microbial Processes and Interactions, Bât. G1 Bio-Industries, Passage des Déportés 2, Gembloux Agro-Bio Tech, University of Liège, 5030 Gembloux, Belgium.
| | - Huu-Thanh Nguyen
- Natural Products and Industrial Biochemistry Research Group (NPIB), Faculty of Applied Sciences, Ton Duc Thang University, 19 Nguyen Huu Tho, Tan Phong Ward, District 7, 700000 Ho Chi Minh City, Vietnam.
- Microbial Processes and Interactions, Bât. G1 Bio-Industries, Passage des Déportés 2, Gembloux Agro-Bio Tech, University of Liège, 5030 Gembloux, Belgium.
| | - Alison Brognaux
- Microbial Processes and Interactions, Bât. G1 Bio-Industries, Passage des Déportés 2, Gembloux Agro-Bio Tech, University of Liège, 5030 Gembloux, Belgium.
| | - Anissa Delepierre
- Microbial Processes and Interactions, Bât. G1 Bio-Industries, Passage des Déportés 2, Gembloux Agro-Bio Tech, University of Liège, 5030 Gembloux, Belgium.
| | - Lies De Clercq
- Department of Applied Analytical and Physical Chemistry, Laboratory of Analytical Chemistry and Applied Ecochemistry, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
| | - Raphaëlle Charlier
- Microbial Processes and Interactions, Bât. G1 Bio-Industries, Passage des Déportés 2, Gembloux Agro-Bio Tech, University of Liège, 5030 Gembloux, Belgium.
| | - Evi Michels
- Department of Applied Analytical and Physical Chemistry, Laboratory of Analytical Chemistry and Applied Ecochemistry, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
| | - Erik Meers
- Department of Applied Analytical and Physical Chemistry, Laboratory of Analytical Chemistry and Applied Ecochemistry, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
| | - Frank Delvigne
- Natural Products and Industrial Biochemistry Research Group (NPIB), Faculty of Applied Sciences, Ton Duc Thang University, 19 Nguyen Huu Tho, Tan Phong Ward, District 7, 700000 Ho Chi Minh City, Vietnam.
- Microbial Processes and Interactions, Bât. G1 Bio-Industries, Passage des Déportés 2, Gembloux Agro-Bio Tech, University of Liège, 5030 Gembloux, Belgium.
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11
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Oikonomou CM, Chang YW, Jensen GJ. A new view into prokaryotic cell biology from electron cryotomography. Nat Rev Microbiol 2016; 14:205-20. [PMID: 26923112 PMCID: PMC5551487 DOI: 10.1038/nrmicro.2016.7] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Electron cryotomography (ECT) enables intact cells to be visualized in 3D in an essentially native state to 'macromolecular' (∼4 nm) resolution, revealing the basic architectures of complete nanomachines and their arrangements in situ. Since its inception, ECT has advanced our understanding of many aspects of prokaryotic cell biology, from morphogenesis to subcellular compartmentalization and from metabolism to complex interspecies interactions. In this Review, we highlight how ECT has provided structural and mechanistic insights into the physiology of bacteria and archaea and discuss prospects for the future.
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Affiliation(s)
- Catherine M Oikonomou
- Howard Hughes Medical Institute; Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125, USA
| | - Yi-Wei Chang
- Howard Hughes Medical Institute; Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125, USA
| | - Grant J Jensen
- Howard Hughes Medical Institute; Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125, USA
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12
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Oikonomou C, Swulius M, Briegel A, Beeby M, Yao Q, Chang YW, Jensen G. Electron cryotomography. METHODS IN MICROBIOLOGY 2016. [DOI: 10.1016/bs.mim.2016.10.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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13
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WOLF SHARONGRAYER, REZ PETER, ELBAUM MICHAEL. Phosphorus detection in vitrified bacteria by cryo-STEM annular dark-field analysis. J Microsc 2015. [DOI: 10.1111/jmi.12289] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- SHARON GRAYER WOLF
- Department of Chemical Research Support; Weizmann Institute of Science; Rehovot Israel
| | - PETER REZ
- Department of Physics; Arizona State University; Tempe Arizona U.S.A
| | - MICHAEL ELBAUM
- Department of Materials and Interfaces; Weizmann Institute of Science; Rehovot Israel
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14
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Delgado L, Martínez G, López-Iglesias C, Mercadé E. Cryo-electron tomography of plunge-frozen whole bacteria and vitreous sections to analyze the recently described bacterial cytoplasmic structure, the Stack. J Struct Biol 2015; 189:220-9. [PMID: 25617813 DOI: 10.1016/j.jsb.2015.01.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 01/13/2015] [Indexed: 11/25/2022]
Abstract
Cryo-electron tomography (CET) of plunge-frozen whole bacteria and vitreous sections (CETOVIS) were used to revise and expand the structural knowledge of the "Stack", a recently described cytoplasmic structure in the Antarctic bacterium Pseudomonas deceptionensis M1(T). The advantages of both techniques can be complementarily combined to obtain more reliable insights into cells and their components with three-dimensional imaging at different resolutions. Cryo-electron microscopy (Cryo-EM) and CET of frozen-hydrated P. deceptionensis M1(T) cells confirmed that Stacks are found at different locations within the cell cytoplasm, in variable number, separately or grouped together, very close to the plasma membrane (PM) and oriented at different angles (from 35° to 90°) to the PM, thus establishing that they were not artifacts of the previous sample preparation methods. CET of plunge-frozen whole bacteria and vitreous sections verified that each Stack consisted of a pile of oval disc-like subunits, each disc being surrounded by a lipid bilayer membrane and separated from each other by a constant distance with a mean value of 5.2±1.3nm. FM4-64 staining and confocal microscopy corroborated the lipid nature of the membrane of the Stacked discs. Stacks did not appear to be invaginations of the PM because no continuity between both membranes was visible when whole bacteria were analyzed. We are still far from deciphering the function of these new structures, but a first experimental attempt links the Stacks with a given phase of the cell replication process.
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Affiliation(s)
- Lidia Delgado
- Cryo-Electron Microscopy, Scientific and Technological Centers, University of Barcelona, Barcelona, Spain; Department of Microbiology, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - Gema Martínez
- Cryo-Electron Microscopy, Scientific and Technological Centers, University of Barcelona, Barcelona, Spain
| | - Carmen López-Iglesias
- Cryo-Electron Microscopy, Scientific and Technological Centers, University of Barcelona, Barcelona, Spain.
| | - Elena Mercadé
- Department of Microbiology, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain.
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15
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Müller A, Beeby M, McDowall AW, Chow J, Jensen GJ, Clemons WM. Ultrastructure and complex polar architecture of the human pathogen Campylobacter jejuni. Microbiologyopen 2014; 3:702-10. [PMID: 25065852 PMCID: PMC4234261 DOI: 10.1002/mbo3.200] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 06/17/2014] [Accepted: 06/27/2014] [Indexed: 12/12/2022] Open
Abstract
Campylobacter jejuni is one of the most successful food-borne human pathogens. Here we use electron cryotomography to explore the ultrastructure of C. jejuni cells in logarithmically growing cultures. This provides the first look at this pathogen in a near-native state at macromolecular resolution (~5 nm). We find a surprisingly complex polar architecture that includes ribosome exclusion zones, polyphosphate storage granules, extensive collar-shaped chemoreceptor arrays, and elaborate flagellar motors.
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Affiliation(s)
- Axel Müller
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, California, 91125
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16
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Polyphosphate storage during sporulation in the gram-negative bacterium Acetonema longum. J Bacteriol 2013; 195:3940-6. [PMID: 23813732 DOI: 10.1128/jb.00712-13] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Using electron cryotomography, we show that the Gram-negative sporulating bacterium Acetonema longum synthesizes high-density storage granules at the leading edges of engulfing membranes. The granules appear in the prespore and increase in size and number as engulfment proceeds. Typically, a cluster of 8 to 12 storage granules closely associates with the inner spore membrane and ultimately accounts for ∼7% of the total volume in mature spores. Energy-dispersive X-ray spectroscopy (EDX) analyses show that the granules contain high levels of phosphorus, oxygen, and magnesium and therefore are likely composed of polyphosphate (poly-P). Unlike the Gram-positive Bacilli and Clostridia, A. longum spores retain their outer spore membrane upon germination. To explore the possibility that the granules in A. longum may be involved in this unique process, we imaged purified Bacillus cereus, Bacillus thuringiensis, Bacillus subtilis, and Clostridium sporogenes spores. Even though B. cereus and B. thuringiensis contain the ppk and ppx genes, none of the spores from Gram-positive bacteria had granules. We speculate that poly-P in A. longum may provide either the energy or phosphate metabolites needed for outgrowth while retaining an outer membrane.
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17
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Henry JT, Crosson S. Chromosome replication and segregation govern the biogenesis and inheritance of inorganic polyphosphate granules. Mol Biol Cell 2013; 24:3177-86. [PMID: 23985321 PMCID: PMC3806658 DOI: 10.1091/mbc.e13-04-0182] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Prokaryotes and eukaryotes synthesize long chains of orthophosphate, known as polyphosphate (polyP), which form dense granules within the cell. PolyP regulates myriad cellular functions and is often localized to specific subcellular addresses through mechanisms that remain undefined. In this study, we present a molecular-level analysis of polyP subcellular localization in the model bacterium Caulobacter crescentus. We demonstrate that biogenesis and localization of polyP is controlled as a function of the cell cycle, which ensures regular partitioning of granules between mother and daughter. The enzyme polyphosphate kinase 1 (Ppk1) is required for granule production, colocalizes with granules, and dynamically localizes to the sites of new granule synthesis in nascent daughter cells. Localization of Ppk1 within the cell requires an intact catalytic active site and a short, positively charged tail at the C-terminus of the protein. The processes of chromosome replication and segregation govern both the number and position of Ppk1/polyP complexes within the cell. We propose a multistep model in which the chromosome establishes sites of polyP coalescence, which recruit Ppk1 to promote the in situ synthesis of large granules. These findings underscore the importance of both chromosome dynamics and discrete protein localization as organizing factors in bacterial cell biology.
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Affiliation(s)
- Jonathan T Henry
- Committee on Microbiology, University of Chicago, Chicago, IL 60637 Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637
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18
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Single particle and molecular assembly analysis of polyribosomes by single- and double-tilt cryo electron tomography. Ultramicroscopy 2013; 126:33-9. [DOI: 10.1016/j.ultramic.2012.12.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 11/27/2012] [Accepted: 12/07/2012] [Indexed: 11/19/2022]
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19
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Abreu F, Sousa AA, Aronova MA, Kim Y, Cox D, Leapman RD, Andrade LR, Kachar B, Bazylinski DA, Lins U. Cryo-electron tomography of the magnetotactic vibrio Magnetovibrio blakemorei: insights into the biomineralization of prismatic magnetosomes. J Struct Biol 2012; 181:162-8. [PMID: 23246783 DOI: 10.1016/j.jsb.2012.12.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 11/10/2012] [Accepted: 12/05/2012] [Indexed: 11/28/2022]
Abstract
We examined the structure and biomineralization of prismatic magnetosomes in the magnetotactic marine vibrio Magnetovibrio blakemorei strain MV-1 and a non-magnetotactic mutant derived from it, using a combination of cryo-electron tomography and freeze-fracture. The vesicles enveloping the Magnetovibrio magnetosomes were elongated and detached from the cell membrane. Magnetosome crystal formation appeared to be initiated at a nucleation site on the membrane inner surface. Interestingly, while scattered filaments were observed in the surrounding cytoplasm, their association with the magnetosome chains could not be unequivocally established. Our data suggest fundamental differences between prismatic and octahedral magnetosomes in their mechanisms of nucleation and crystal growth as well as in their structural relationships with the cytoplasm and plasma membrane.
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Affiliation(s)
- Fernanda Abreu
- Instituto de Microbiologia Paulo de Góes, CCS, Bloco I, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-590, Brazil
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20
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Advances in techniques for phosphorus analysis in biological sources. Curr Opin Biotechnol 2012; 23:852-9. [DOI: 10.1016/j.copbio.2012.06.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 06/08/2012] [Accepted: 06/14/2012] [Indexed: 10/28/2022]
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21
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Mycobacterium marinum SecA2 promotes stable granulomas and induces tumor necrosis factor alpha in vivo. Infect Immun 2012; 80:3512-20. [PMID: 22851747 DOI: 10.1128/iai.00686-12] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
SecA2 is an ATPase present in some pathogenic Gram-positive bacteria, is required for translocation of a limited set of proteins across the cytosolic membrane, and plays an important role in virulence in several bacteria, including mycobacteria that cause diseases such as tuberculosis and leprosy. However, the mechanisms by which SecA2 affects virulence are incompletely understood. To investigate whether SecA2 modulates host immune responses in vivo, we studied Mycobacterium marinum infection in two different hosts: an established zebrafish model and a recently described mouse model. Here we show that M. marinum ΔsecA2 was attenuated for virulence in both host species and SecA2 was needed for normal granuloma numbers and for optimal tumor necrosis factor alpha response in both zebrafish and mice. M. marinum ΔsecA2 was more sensitive to SDS and had unique protrusions from its cell envelope when examined by cryo-electron tomography, suggesting that SecA2 is important for bacterial cell wall integrity. These results provide evidence that SecA2 induces granulomas and is required for bacterial modulation of the host response because it affects the mycobacterial cell envelope.
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22
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Three-dimensional structures of pathogenic and saprophytic Leptospira species revealed by cryo-electron tomography. J Bacteriol 2012; 194:1299-306. [PMID: 22228733 DOI: 10.1128/jb.06474-11] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Leptospira interrogans is the primary causative agent of the most widespread zoonotic disease, leptospirosis. An in-depth structural characterization of L. interrogans is needed to understand its biology and pathogenesis. In this study, cryo-electron tomography (cryo-ET) was used to compare pathogenic and saprophytic species and examine the unique morphological features of this group of bacteria. Specifically, our study revealed a structural difference between the cell envelopes of L. interrogans and Leptospira biflexa involving variations in the lipopolysaccharide (LPS) layer. Through cryo-ET and subvolume averaging, we determined the first three-dimensional (3-D) structure of the flagellar motor of leptospira, with novel features in the flagellar C ring, export apparatus, and stator. Together with direct visualization of chemoreceptor arrays, DNA packing, periplasmic filaments, spherical cytoplasmic bodies, and a unique "cap" at the cell end, this report provides structural insights into these fascinating Leptospira species.
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23
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Growth and localization of polyhydroxybutyrate granules in Ralstonia eutropha. J Bacteriol 2011; 194:1092-9. [PMID: 22178974 DOI: 10.1128/jb.06125-11] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The bacterium Ralstonia eutropha forms cytoplasmic granules of polyhydroxybutyrate that are a source of biodegradable thermoplastic. While much is known about the biochemistry of polyhydroxybutyrate production, the cell biology of granule formation and growth remains unclear. Previous studies have suggested that granules form either in the inner membrane, on a central scaffold, or in the cytoplasm. Here we used electron cryotomography to monitor granule genesis and development in 3 dimensions (3-D) in a near-native, "frozen-hydrated" state in intact Ralstonia eutropha cells. Neither nascent granules within the cell membrane nor scaffolds were seen. Instead, granules of all sizes resided toward the center of the cytoplasm along the length of the cell and exhibited a discontinuous surface layer more consistent with a partial protein coating than either a lipid mono- or bilayer. Putatively fusing granules were also seen, suggesting that small granules are continually generated and then grow and merge. Together, these observations support a model of biogenesis wherein granules form in the cytoplasm coated not by phospholipid but by protein. Previous thin-section electron microscopy (EM), fluorescence microscopy, and atomic force microscopy (AFM) results to the contrary may reflect both differences in nucleoid condensation and specimen preparation-induced artifacts.
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24
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ppGpp and polyphosphate modulate cell cycle progression in Caulobacter crescentus. J Bacteriol 2011; 194:28-35. [PMID: 22020649 DOI: 10.1128/jb.05932-11] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Caulobacter crescentus differentiates from a motile, foraging swarmer cell into a sessile, replication-competent stalked cell during its cell cycle. This developmental transition is inhibited by nutrient deprivation to favor the motile swarmer state. We identify two cell cycle regulatory signals, ppGpp and polyphosphate (polyP), that inhibit the swarmer-to-stalked transition in both complex and glucose-exhausted media, thereby increasing the proportion of swarmer cells in mixed culture. Upon depletion of available carbon, swarmer cells lacking the ability to synthesize ppGpp or polyP improperly initiate chromosome replication, proteolyze the replication inhibitor CtrA, localize the cell fate determinant DivJ, and develop polar stalks. Furthermore, we show that swarmer cells produce more ppGpp than stalked cells upon starvation. These results provide evidence that ppGpp and polyP are cell-type-specific developmental regulators.
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25
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Singer E, Emerson D, Webb EA, Barco RA, Kuenen JG, Nelson WC, Chan CS, Comolli LR, Ferriera S, Johnson J, Heidelberg JF, Edwards KJ. Mariprofundus ferrooxydans PV-1 the first genome of a marine Fe(II) oxidizing Zetaproteobacterium. PLoS One 2011; 6:e25386. [PMID: 21966516 PMCID: PMC3179512 DOI: 10.1371/journal.pone.0025386] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 09/02/2011] [Indexed: 12/21/2022] Open
Abstract
Mariprofundus ferrooxydans PV-1 has provided the first genome of the recently discovered Zetaproteobacteria subdivision. Genome analysis reveals a complete TCA cycle, the ability to fix CO(2), carbon-storage proteins and a sugar phosphotransferase system (PTS). The latter could facilitate the transport of carbohydrates across the cell membrane and possibly aid in stalk formation, a matrix composed of exopolymers and/or exopolysaccharides, which is used to store oxidized iron minerals outside the cell. Two-component signal transduction system genes, including histidine kinases, GGDEF domain genes, and response regulators containing CheY-like receivers, are abundant and widely distributed across the genome. Most of these are located in close proximity to genes required for cell division, phosphate uptake and transport, exopolymer and heavy metal secretion, flagellar biosynthesis and pilus assembly suggesting that these functions are highly regulated. Similar to many other motile, microaerophilic bacteria, genes encoding aerotaxis as well as antioxidant functionality (e.g., superoxide dismutases and peroxidases) are predicted to sense and respond to oxygen gradients, as would be required to maintain cellular redox balance in the specialized habitat where M. ferrooxydans resides. Comparative genomics with other Fe(II) oxidizing bacteria residing in freshwater and marine environments revealed similar content, synteny, and amino acid similarity of coding sequences potentially involved in Fe(II) oxidation, signal transduction and response regulation, oxygen sensation and detoxification, and heavy metal resistance. This study has provided novel insights into the molecular nature of Zetaproteobacteria.
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Affiliation(s)
- Esther Singer
- Geomicrobiology Group, Department of Earth Sciences, University of Southern California, Los Angeles, California, United States of America
| | - David Emerson
- Bigelow Laboratory for Ocean Sciences, West Boothbay Harbor, Maine, United States of America
| | - Eric A. Webb
- Department of Biological Sciences, Marine Environmental Biology Section, University of Southern California, Los Angeles, California, United States of America
| | - Roman A. Barco
- Department of Biological Sciences, Marine Environmental Biology Section, University of Southern California, Los Angeles, California, United States of America
| | - J. Gijs Kuenen
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - William C. Nelson
- Department of Biological Sciences, Marine Environmental Biology Section, University of Southern California, Los Angeles, California, United States of America
| | - Clara S. Chan
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, United States of America
| | - Luis R. Comolli
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Steve Ferriera
- J. Craig Venter Institute, San Diego, California, United States of America
| | - Justin Johnson
- J. Craig Venter Institute, San Diego, California, United States of America
| | - John F. Heidelberg
- Department of Biological Sciences, Marine Environmental Biology Section, University of Southern California, Los Angeles, California, United States of America
| | - Katrina J. Edwards
- Geomicrobiology Group, Department of Earth Sciences, University of Southern California, Los Angeles, California, United States of America
- Department of Biological Sciences, Marine Environmental Biology Section, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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26
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Comolli LR, Luef B, Chan CS. High-resolution 2D and 3D cryo-TEM reveals structural adaptations of two stalk-forming bacteria to an Fe-oxidizing lifestyle. Environ Microbiol 2011; 13:2915-29. [PMID: 21895918 DOI: 10.1111/j.1462-2920.2011.02567.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aerobic neutrophilic Fe-oxidizing bacteria (FeOB) thrive where oxic and iron-rich anoxic waters meet. Here, iron microbial mats are commonly developed by stalk-forming Fe-oxidizers adapted to these iron-rich gradient environments, somehow avoiding iron encrustation. Few details are known about FeOB physiology; thus, the bases of these adaptations, notably the mechanisms of interactions with iron, are poorly understood. We examined two stalked FeOB: the marine Zetaproteobacterium Mariprofundus ferrooxydans and a terrestrial Betaproteobacterium Gallionella-like organism. We used cryo-transmission electron microscopy and cryo-electron tomography to provide unprecedented ultrastructural data on intact cell-mineral systems. Both FeOB localize iron mineral formation at stalk extrusion sites, while avoiding surface and periplasmic mineralization. The M. ferrooxydans cell surface is densely covered in fibrils while the terrestrial FeOB surface is smooth, suggesting a difference in surface chemistry. Only the terrestrial FeOB exhibited a putative chemotaxis apparatus, which may be due to differences in chemotaxis mechanisms. Both FeOB have a single flagellum, which alone is insufficient to account for cell motion during iron oxidation, suggesting that stalk extrusion is a mechanism for motility. Our results delineate the physical framework of iron transformations and characterize possible structural adaptations to the iron-oxidizing lifestyle. This study shows ultrastructural similarities and differences between two distinct FeOB, setting the stage for further (e.g. genomic) comparisons that will help us understand functional differences and evolutionary history.
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Affiliation(s)
- Luis R Comolli
- Lawrence Berkeley National Laboratory, Life Sciences Division, Berkeley, CA 94720, USA.
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27
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Thomson NM, Channon K, Mokhtar NA, Staniewicz L, Rai R, Roy I, Sato S, Tsuge T, Donald AM, Summers D, Sivaniah E. Imaging internal features of whole, unfixed bacteria. SCANNING 2011; 33:59-68. [PMID: 21344457 DOI: 10.1002/sca.20221] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 01/21/2011] [Indexed: 05/30/2023]
Abstract
Wet scanning-transmission electron microscopy (STEM) is a technique that allows high-resolution transmission imaging of biological samples in a hydrated state, with minimal sample preparation. However, it has barely been used for the study of bacterial cells. In this study, we present an analysis of the advantages and disadvantages of wet STEM compared with standard transmission electron microscopy (TEM). To investigate the potential applications of wet STEM, we studied the growth of polyhydroxyalkanoate and triacylglycerol carbon storage inclusions. These were easily visible inside cells, even in the early stages of accumulation. Although TEM produces higher resolution images, wet STEM is useful when preservation of the sample is important or when studying the relative sizes of different features, since samples do not need to be sectioned. Furthermore, under carefully selected conditions, it may be possible to maintain cell viability, enabling new types of experiments to be carried out. To our knowledge, internal features of bacterial cells have not been imaged previously by this technique.
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Affiliation(s)
- Nicholas M Thomson
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
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28
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BLECK C, MERZ A, GUTIERREZ M, WALTHER P, DUBOCHET J, ZUBER B, GRIFFITHS G. Comparison of different methods for thin section EM analysis of Mycobacterium smegmatis. J Microsc 2010; 237:23-38. [DOI: 10.1111/j.1365-2818.2009.03299.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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29
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Abstract
Some bacteria are amongst the most important model organisms for biology and medicine. Here we review how electron microscopes have been used to image bacterial cells, summarizing the technical details of the various methods, the advantages and disadvantages of each, and the major biological insights that have been obtained. Three specific example structures, "mesosomes," "cytoskeletal filaments," and "nucleoid," are used to illustrate how methodological advances have shaped our understanding of bacterial ultrastructure. Methods that involve dehydration and metal stains are widely practiced and have revealed many ultrastructural features, but they can generate misleading artifacts and have failed to preserve important structures such as the bacterial cytoskeleton. The invention of cryo-electron microscopy, which allows bacterial cells to be imaged in a frozen-hydrated, near-native state without the need for dehydration and stains, has now led to important new insights. Efforts to identify structures and localize specific proteins in cryo-EM images are summarized.
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30
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Organization, structure, and assembly of alpha-carboxysomes determined by electron cryotomography of intact cells. J Mol Biol 2009; 396:105-17. [PMID: 19925807 DOI: 10.1016/j.jmb.2009.11.019] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Revised: 11/06/2009] [Accepted: 11/09/2009] [Indexed: 12/31/2022]
Abstract
Carboxysomes are polyhedral inclusion bodies that play a key role in autotrophic metabolism in many bacteria. Using electron cryotomography, we examined carboxysomes in their native states within intact cells of three chemolithoautotrophic bacteria. We found that carboxysomes generally cluster into distinct groups within the cytoplasm, often in the immediate vicinity of polyphosphate granules, and a regular lattice of density frequently connects granules to nearby carboxysomes. Small granular bodies were also seen within carboxysomes. These observations suggest a functional relationship between carboxysomes and polyphosphate granules. Carboxysomes exhibited greater size, shape, and compositional variability in cells than in purified preparations. Finally, we observed carboxysomes in various stages of assembly, as well as filamentous structures that we attribute to misassembled shell protein. Surprisingly, no more than one partial carboxysome was ever observed per cell. Based on these observations, we propose a model for carboxysome assembly in which the shell and the internal RuBisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) lattice form simultaneously, likely guided by specific interactions between shell proteins and RuBisCOs.
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31
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Milne JLS, Subramaniam S. Cryo-electron tomography of bacteria: progress, challenges and future prospects. Nat Rev Microbiol 2009; 7:666-75. [PMID: 19668224 DOI: 10.1038/nrmicro2183] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Recent advances in three-dimensional electron microscopy provide remarkable tools to image the interior of bacterial cells. Glimpses of cells at resolutions that are 1-2 orders of magnitude higher than those currently attained with light microscopy can now be obtained with cryo-electron tomography, especially when used in combination with new tools for image averaging. This Review highlights recent advances in this area and provides an assessment of the general applicability, current limitations and type of structural information that can be obtained about the organization of intact cells using tomography. Possible future directions for whole cell imaging are also discussed.
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Affiliation(s)
- Jacqueline L S Milne
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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Abstract
Inorganic polyphosphate (Poly P) is a polymer of tens to hundreds of phosphate residues linked by "high-energy" phosphoanhydride bonds as in ATP. Found in abundance in all cells in nature, it is unique in its likely role in the origin and survival of species. Here, we present extensive evidence that the remarkable properties of Poly P as a polyanion have made it suited for a crucial role in the emergence of cells on earth. Beyond that, Poly P has proved in a variety of ways to be essential for growth of cells, their responses to stresses and stringencies, and the virulence of pathogens. In this review, we pay particular attention to the enzyme, polyphosphate kinase 1 (Poly P kinase 1 or PPK1), responsible for Poly P synthesis and highly conserved in many bacterial species, including 20 or more of the major pathogens. Mutants lacking PPK1 are defective in motility, quorum sensing, biofilm formation, and virulence. Structural studies are cited that reveal the conserved ATP-binding site of PPK1 at atomic resolution and reveal that the site can be blocked with minute concentrations of designed inhibitors. Another widely conserved enzyme is PPK2, which has distinctive kinetic properties and is also implicated in the virulence of some pathogens. Thus, these enzymes, absent in yeast and animals, are novel attractive targets for treatment of many microbial diseases. Still another enzyme featured in this review is one discovered in Dictyostelium discoideum that becomes an actin-like fiber concurrent with the synthesis, step by step, of a Poly P chain made from ATP. The Poly P-actin fiber complex, localized in the cell, lengthens and recedes in response to metabolic signals. Homologs of DdPPK2 are found in pathogenic protozoa and in the alga Chlamydomonas. Beyond the immediate relevance of Poly P as a target for anti-infective drugs, a large variety of cellular operations that rely on Poly P will be considered.
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Affiliation(s)
- Narayana N Rao
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA.
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33
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Cryo-electron tomography in biology and medicine. Ann Anat 2009; 191:427-45. [PMID: 19559584 DOI: 10.1016/j.aanat.2009.04.003] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Accepted: 04/23/2009] [Indexed: 12/16/2022]
Abstract
During the last six decades electron microscopy (EM) has been essential to ultra-structural studies of the cell to understand the fundamentals of cellular morphology and processes underlying diseases. More recently, electron tomography (ET) has emerged as a novel approach able to provide three-dimensional (3D) information on cells and tissues at molecular level. Electron tomography is comparable to medical tomographic techniques like CAT, PET and MRI in the sense that it provides a 3D view of an object, yet it does so at a cellular scale and with nanometer resolution. Electron tomography has the unique ability to visualize molecular assemblies, cytoskeletal elements and organelles within cells. The three-dimensional perspective it provides has revised our understanding of cellular organization and its relation with morphological changes in normal development and disease. Cryo-electron tomography of vitrified samples at cryogenic temperatures combines excellent structural preservation with direct high-resolution imaging. The use of cryo-preparation and imaging techniques eliminates artifacts induced by plastic embedding and staining of the samples is circumvented. This review describes the technique of cryo-electron tomography, its basic principles, cryo-specimen preparation, tomographic data acquisition and image processing. A number of illustrative examples ranging from whole cells, cytoskeletal filaments, viruses and organelles are presented along with a comprehensive list of research articles employing cryo-electron tomography as the key ultrastuctural technique.
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34
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Sorzano COS, Messaoudi C, Eibauer M, Bilbao-Castro JR, Hegerl R, Nickell S, Marco S, Carazo JM. Marker-free image registration of electron tomography tilt-series. BMC Bioinformatics 2009; 10:124. [PMID: 19397789 PMCID: PMC2694187 DOI: 10.1186/1471-2105-10-124] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Accepted: 04/27/2009] [Indexed: 12/03/2022] Open
Abstract
Background Tilt series are commonly used in electron tomography as a means of collecting three-dimensional information from two-dimensional projections. A common problem encountered is the projection alignment prior to 3D reconstruction. Current alignment techniques usually employ gold particles or image derived markers to correctly align the images. When these markers are not present, correlation between adjacent views is used to align them. However, sequential pairwise correlation is prone to bias and the resulting alignment is not always optimal. Results In this paper we introduce an algorithm to find regions of the tilt series which can be tracked within a subseries of the tilt series. These regions act as landmarks allowing the determination of the alignment parameters. We show our results with synthetic data as well as experimental cryo electron tomography. Conclusion Our algorithm is able to correctly align a single-tilt tomographic series without the help of fiducial markers thanks to the detection of thousands of small image patches that can be tracked over a short number of images in the series.
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35
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JONIĆ S, SORZANO C, BOISSET N. Comparison of single-particle analysis and electron tomography approaches: an overview. J Microsc 2008; 232:562-79. [DOI: 10.1111/j.1365-2818.2008.02119.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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36
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Affiliation(s)
- Dylan M. Morris
- Division of Biology, California Institute of Technology, Pasadena, California 91125;
| | - Grant J. Jensen
- Division of Biology, California Institute of Technology, Pasadena, California 91125;
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Three-dimensional imaging of the highly bent architecture of Bdellovibrio bacteriovorus by using cryo-electron tomography. J Bacteriol 2008; 190:2588-96. [PMID: 18203829 DOI: 10.1128/jb.01538-07] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bdellovibrio bacteriovorus cells are small deltaproteobacterial cells that feed on other gram-negative bacteria, including human pathogens. Using cryo-electron tomography, we demonstrated that B. bacteriovorus cells are capable of substantial flexibility and local deformation of the outer and inner membranes without loss of cell integrity. These shape changes can occur in less than 2 min, and analysis of the internal architecture of highly bent cells showed that the overall distribution of molecular machines and the nucleoid is similar to that in moderately bent cells. B. bacteriovorus cells appear to contain an extensive internal network of short and long filamentous structures. We propose that rearrangements of these structures, in combination with the unique properties of the cell envelope, may underlie the remarkable ability of B. bacteriovorus cells to find and enter bacterial prey.
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Koning RI, Zovko S, Bárcena M, Oostergetel GT, Koerten HK, Galjart N, Koster AJ, Mieke Mommaas A. Cryo electron tomography of vitrified fibroblasts: microtubule plus ends in situ. J Struct Biol 2007; 161:459-68. [PMID: 17923421 DOI: 10.1016/j.jsb.2007.08.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Revised: 08/14/2007] [Accepted: 08/16/2007] [Indexed: 11/25/2022]
Abstract
Mouse embryonic fibroblasts (MEFs) are cells that have highly suitable biophysical properties for cellular cryo electron tomography. MEFs can be grown directly on carbon supported by EM grids. They stretch out and grow thinner than 500nm over major parts of the cell, attaining a minimal thickness of 50nm at their cortex. This facilitates direct cryo-fixation by plunge-freezing and high resolution cryo electron tomography. Both by direct cryo electron microscopy projection imaging and cryo electron tomography of vitrified MEFs we visualized a variety of cellular structures like ribosomes, vesicles, mitochondria, rough endoplasmatic reticulum, actin filaments, intermediate filaments and microtubules. MEFs are primary cells that closely resemble native tissue and are highly motile. Therefore, they are attractive for studying cytoskeletal elements. Here we report on structural investigations of microtubule plus ends. We were able to visualize single frayed protofilaments at the microtubule plus end in vitrified fibroblasts using cryo electron tomography. Furthermore, it appeared that MEFs contain densities inside their microtubules, although 2.5-3.5 times less than in neuronal cells [Garvalov, B.K., Zuber, B., Bouchet-Marquis, C., Kudryashev, M., Gruska, M., Beck, M., Leis, A., Frischknecht, F., Bradke, F., Baumeister, W., Dubochet, J., and Cyrklaff, M. 2006. Luminal particles within cellular microtubules. J. Cell Biol. 174, 759-765]. Projection imaging of cellular microtubule plus ends showed that 40% was frayed, which is two times more than expected when compared to microtubule growth and shrinkage rates in MEFs. This suggests that frayed ends might be stabilized in the cell cortex.
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Affiliation(s)
- Roman I Koning
- Department of Molecular Cell Biology, Section Electron Microscopy, Leiden University Medical Center, P.O. Box 9600, 2300 RC, Leiden, The Netherlands.
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Jensen GJ, Briegel A. How electron cryotomography is opening a new window onto prokaryotic ultrastructure. Curr Opin Struct Biol 2007; 17:260-7. [PMID: 17398087 DOI: 10.1016/j.sbi.2007.03.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Revised: 02/13/2007] [Accepted: 03/12/2007] [Indexed: 11/22/2022]
Abstract
Electron cryotomography is an emerging technology that enables thin samples, including small intact prokaryotic cells, to be imaged in three dimensions in a near-native 'frozen-hydrated' state to a resolution sufficient to recognize very large macromolecular complexes in situ. Following years of visionary technology development by a few key pioneers, several laboratories are now using the technique to produce biological results of major significance in the field of prokaryotic ultrastructure. Recent discoveries have included the surprising generality and complexity of the cytoskeleton, the connectivity of key membrane compartments, the location and architecture of large macromolecular machines such as the ribosome and flagellar motors, and the structure of some extraordinary external appendages. Through further technology development, identification of the most revealing model systems and sustained effort, electron cryotomography is poised to help resolve many fundamentally important questions about prokaryotic ultrastructure.
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Affiliation(s)
- Grant J Jensen
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
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