1
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Ryan PM, Shaevitz JW, Wolgemuth CW. Bend or Twist? What Plectonemes Reveal about the Mysterious Motility of Spiroplasma. PHYSICAL REVIEW LETTERS 2023; 131:178401. [PMID: 37955476 DOI: 10.1103/physrevlett.131.178401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 09/15/2023] [Indexed: 11/14/2023]
Abstract
Spiroplasma is a unique, helical bacterium that lacks a cell wall and swims using propagating helix hand inversions. These deformations are likely driven by a set of cytoskeletal filaments, but how remains perplexing. Here, we probe the underlying mechanism using a model where either twist or bend drive spiroplasma's chirality inversions. We show that Spiroplasma should wrap into plectonemes at different values of the length and external viscosity, depending on the mechanism. Then, by experimentally measuring the bending modulus of Spiroplasma and if and when plectonemes form, we show that Spiroplasma's helix hand inversions are likely driven by bending.
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Affiliation(s)
- Paul M Ryan
- Department of Physics, University of Arizona, Tucson, Arizona 85721, USA
| | - Joshua W Shaevitz
- Joseph Henry Laboratories of Physics and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, USA
| | - Charles W Wolgemuth
- Department of Physics, University of Arizona, Tucson, Arizona 85721, USA
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721, USA
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2
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Takahashi D, Miyata M, Fujiwara I. Assembly properties of Spiroplasma MreB involved in swimming motility. J Biol Chem 2023:104793. [PMID: 37150324 DOI: 10.1016/j.jbc.2023.104793] [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: 01/26/2023] [Revised: 04/29/2023] [Accepted: 05/02/2023] [Indexed: 05/09/2023] Open
Abstract
Bacterial actin MreB forms filaments formed of antiparallel double strand units. The wall-less helical bacterium Spiroplasma has five MreB homologs (MreB1-5), some of which are involved in an intra-cellular ribbon for driving the bacterium's swimming motility. Although the interaction between MreB units is important for understanding Spiroplasma swimming, the interaction modes of each ribbon component are unclear. Here, we examined the assembly properties of Spiroplasma eriocheiris MreB5 (SpeMreB5), one of the ribbon component proteins that forms sheets. Electron microscopy (EM) revealed that sheet formation was inhibited under acidic conditions and bundle structures were formed under acidic and neutral conditions with low ionic strength. We also used solution assays and identified four properties of SpeMreB5 bundles as follows: (I) bundle formation followed sheet formation; (II) electrostatic interactions were required for bundle formation; (III) the positively charged and unstructured C-terminal region contributed to promoting lateral interactions for bundle formation; and (IV) bundle formation required Mg2+ at neutral pH but was inhibited by divalent cations under acidic pH conditions. During these studies, we also characterized two aggregation modes of SpeMreB5 with distinct responses to ATP. These properties will shed light on SpeMreB5 assembly dynamics at the molecular level.
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Affiliation(s)
- Daichi Takahashi
- Graduate School of Science, Osaka Metropolitan University, Osaka, Japan
| | - Makoto Miyata
- Graduate School of Science, Osaka Metropolitan University, Osaka, Japan; The OMU Advanced Research Center for Natural Science and Technology, Osaka Metropolitan University, Osaka, Japan
| | - Ikuko Fujiwara
- Graduate School of Science, Osaka Metropolitan University, Osaka, Japan; The OMU Advanced Research Center for Natural Science and Technology, Osaka Metropolitan University, Osaka, Japan; Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan.
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3
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Swimming Motility Assays of Spiroplasma. Methods Mol Biol 2023; 2646:373-381. [PMID: 36842131 DOI: 10.1007/978-1-0716-3060-0_31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
Spiroplasma swim in liquids without the use of the bacterial flagella. This small helical bacterium propels itself by generating kinks that travel down the cell body. The kink translation is unidirectional, from the leading pole to the lagging pole, during cell swimming in viscous environments. This protocol describes a swimming motility assay of Spiroplasma eriocheiris for visualizing kink translations of the absolute handedness of the body helix with optical microscopy.
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4
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Purification and ATPase Activity Measurement of Spiroplasma MreB. Methods Mol Biol 2023; 2646:359-371. [PMID: 36842130 DOI: 10.1007/978-1-0716-3060-0_30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
Spiroplasma is a genus of wall-less helical bacteria with swimming motility unrelated to conventional types of bacterial motility machinery, such as flagella and pili. The swimming of Spiroplasma is suggested to be driven by five classes of MreB (MreB1-MreB5), which are members of the actin superfamily. In vitro studies of Spiroplasma MreBs have recently been conducted to evaluate their activities, such as ATPase, which is essential for the polymerization dynamics among classic actin superfamily proteins. In this chapter, we describe methods of purification and Pi release measurement of Spiroplasma MreBs using column chromatography and absorption spectroscopy with the molecular probe, 2-amino-6-mercapto-7-methylpurine riboside (MESG). Of note, the methods described here are applicable to other proteins that possess NTPase activity.
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5
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Takahashi D, Miyata M. Sequence analyses of a lipoprotein conserved with bacterial actins responsible for swimming motility of wall-less helical Spiroplasma. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000713. [PMID: 37033705 PMCID: PMC10074174 DOI: 10.17912/micropub.biology.000713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/07/2023] [Accepted: 03/09/2023] [Indexed: 04/11/2023]
Abstract
Spiroplasma is a genus of pathogenic or commensal cell-wall-deficient helical bacterium. Spiroplasma -specific protein fibril and five classes of bacterial actins, MreB1-5, are involved in a helical ribbon structure responsible for helical-cell morphology and swimming motility. A gene for a hypothetical protein-SPE_1229, 7th protein-has been found in the locus coding mreB s. In this study, we characterized the 7th protein using in silico methods and found that it could be a lipoprotein whose gene is encoded downstream of mreB3 and conserved in a clade of Spiroplasma .
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Affiliation(s)
- Daichi Takahashi
- Graduate School of Science, Osaka Metropolitan University, Osaka, Japan
| | - Makoto Miyata
- Graduate School of Science, Osaka Metropolitan University, Osaka, Japan
- The OMU Advanced Research Center for Natural Science and Technology, Osaka Metropolitan University, Osaka, Japan
- Correspondence to: Makoto Miyata (
)
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6
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Kiyama H, Kakizawa S, Sasajima Y, Tahara YO, Miyata M. Reconstitution of a minimal motility system based on Spiroplasma swimming by two bacterial actins in a synthetic minimal bacterium. SCIENCE ADVANCES 2022; 8:eabo7490. [PMID: 36449609 PMCID: PMC9710875 DOI: 10.1126/sciadv.abo7490] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 10/14/2022] [Indexed: 05/24/2023]
Abstract
Motility is one of the most important features of life, but its evolutionary origin remains unknown. In this study, we focused on Spiroplasma, commensal, or parasitic bacteria. They swim by switching the helicity of a ribbon-like cytoskeleton that comprises six proteins, each of which evolved from a nucleosidase and bacterial actin called MreB. We expressed these proteins in a synthetic, nonmotile minimal bacterium, JCVI-syn3B, whose reduced genome was computer-designed and chemically synthesized. The synthetic bacterium exhibited swimming motility with features characteristic of Spiroplasma swimming. Moreover, combinations of Spiroplasma MreB4-MreB5 and MreB1-MreB5 produced a helical cell shape and swimming. These results suggest that the swimming originated from the differentiation and coupling of bacterial actins, and we obtained a minimal system for motility of the synthetic bacterium.
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Affiliation(s)
- Hana Kiyama
- Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
- Graduate School of Science, Osaka Metropolitan University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Shigeyuki Kakizawa
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Yuya Sasajima
- Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
- Graduate School of Science, Osaka Metropolitan University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Yuhei O. Tahara
- Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
- Graduate School of Science, Osaka Metropolitan University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Makoto Miyata
- Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
- Graduate School of Science, Osaka Metropolitan University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
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7
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Cytoskeletal components can turn wall-less spherical bacteria into kinking helices. Nat Commun 2022; 13:6930. [PMID: 36376306 PMCID: PMC9663586 DOI: 10.1038/s41467-022-34478-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 10/26/2022] [Indexed: 11/16/2022] Open
Abstract
Bacterial cell shape is generally determined through an interplay between the peptidoglycan cell wall and cytoplasmic filaments made of polymerized MreB. Indeed, some bacteria (e.g., Mycoplasma) that lack both a cell wall and mreB genes consist of non-motile cells that are spherical or pleomorphic. However, other members of the same class Mollicutes (e.g., Spiroplasma, also lacking a cell wall) display a helical cell shape and kink-based motility, which is thought to rely on the presence of five MreB isoforms and a specific fibril protein. Here, we show that heterologous expression of Spiroplasma fibril and MreB proteins confers helical shape and kinking ability to Mycoplasma capricolum cells. Isoform MreB5 is sufficient to confer helicity and kink propagation to mycoplasma cells. Cryoelectron microscopy confirms the association of cytoplasmic MreB filaments with the plasma membrane, suggesting a direct effect on membrane curvature. However, in our experiments, the heterologous expression of MreBs and fibril did not result in efficient motility in culture broth, indicating that additional, unknown Spiroplasma components are required for swimming.
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8
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Liu P, Li Y, Ye Y, Chen J, Li R, Zhang Q, Li Y, Wang W, Meng Q, Ou J, Yang Z, Sun W, Gu W. The genome and antigen proteome analysis of Spiroplasma mirum. Front Microbiol 2022; 13:996938. [PMID: 36406404 PMCID: PMC9666726 DOI: 10.3389/fmicb.2022.996938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 10/10/2022] [Indexed: 06/16/2023] Open
Abstract
Spiroplasma mirum, small motile wall-less bacteria, was originally isolated from a rabbit tick and had the ability to infect newborn mice and caused cataracts. In this study, the whole genome and antigen proteins of S. mirum were comparative analyzed and investigated. Glycolysis, pentose phosphate pathway, arginine metabolism, nucleotide biosynthesis, and citrate fermentation were found in S. mirum, while trichloroacetic acid, fatty acids metabolism, phospholipid biosynthesis, terpenoid biosynthesis, lactose-specific PTS, and cofactors synthesis were completely absent. The Sec systems of S. mirum consist of SecA, SecE, SecDF, SecG, SecY, and YidC. Signal peptidase II was identified in S. mirum, but no signal peptidase I. The relative gene order in S. mirum is largely conserved. Genome analysis of available species in Mollicutes revealed that they shared only 84 proteins. S. mirum genome has 381 pseudogenes, accounting for 31.6% of total protein-coding genes. This is the evidence that spiroplasma genome is under an ongoing genome reduction. Immunoproteomics, a new scientific technique combining proteomics and immunological analytical methods, provided the direction of our research on S. mirum. We identified 49 proteins and 11 proteins (9 proteins in common) in S. mirum by anti-S. mirum serum and negative serum, respectively. Forty proteins in S. mirum were identified in relation to the virulence. All these proteins may play key roles in the pathogeny and can be used in the future for diagnoses and prevention.
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Affiliation(s)
- Peng Liu
- Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Basic Medical School, Hengyang Medical School, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Yuxin Li
- Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Basic Medical School, Hengyang Medical School, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Youyuan Ye
- Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Basic Medical School, Hengyang Medical School, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Jiaxin Chen
- Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Basic Medical School, Hengyang Medical School, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Rong Li
- Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Basic Medical School, Hengyang Medical School, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Qinyi Zhang
- Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Basic Medical School, Hengyang Medical School, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Yuan Li
- Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Basic Medical School, Hengyang Medical School, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Wen Wang
- Key Laboratory for Aquatic Crustacean Diseases, College of Marine Science and Engineering, Nanjing Normal University, Nanjing, China
| | - Qingguo Meng
- Key Laboratory for Aquatic Crustacean Diseases, College of Marine Science and Engineering, Nanjing Normal University, Nanjing, China
| | - Jingyu Ou
- Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Basic Medical School, Hengyang Medical School, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Zhujun Yang
- Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Basic Medical School, Hengyang Medical School, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Wei Sun
- Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, China
| | - Wei Gu
- Key Laboratory for Aquatic Crustacean Diseases, College of Marine Science and Engineering, Nanjing Normal University, Nanjing, China
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9
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Harne S, Gayathri P. Characterization of heterologously expressed Fibril, a shape and motility determining cytoskeletal protein of the helical bacterium Spiroplasma. iScience 2022; 25:105055. [PMID: 36157586 PMCID: PMC9489929 DOI: 10.1016/j.isci.2022.105055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 06/20/2022] [Accepted: 08/29/2022] [Indexed: 11/30/2022] Open
Abstract
Fibril is a constitutive filament-forming cytoskeletal protein of unidentified fold, exclusive to members of genus Spiroplasma. It is hypothesized to undergo conformational changes necessary to bring about Spiroplasma motility through changes in cell helicity. However, the mechanism driving conformational changes in Fibril remains unknown. We expressed Fibril from S. citri in E. coli for its purification and characterization. Sodium dodecyl sulfate solubilized Fibril filaments and facilitated purification by affinity chromatography. An alternative protocol for obtaining enriched insoluble Fibril filaments was standardized using density gradient centrifugation. Electron microscopy of Fibril purified by these protocols revealed filament bundles. Probable domain boundaries of Fibril protein were identified based on mass spectrometric analysis of proteolytic fragments. Presence of α-helical and β-sheet signatures in FT-IR measurements suggests that Fibril filaments consist of an assembly of folded globular domains, and not a β-strand-based aggregation like amyloid fibrils. Codon-optimized Spiroplasma citri Fibril was expressed in E. coli SDS treatment does not denature Fibril filaments Fibril possesses α helices and β sheet and is not an amyloid-like protein Domain boundaries were predicted using mass spectrometry of proteolytic fragments
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Affiliation(s)
- Shrikant Harne
- Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
| | - Pananghat Gayathri
- Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
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10
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Takahashi D, Fujiwara I, Sasajima Y, Narita A, Imada K, Miyata M. ATP-dependent polymerization dynamics of bacterial actin proteins involved in Spiroplasma swimming. Open Biol 2022; 12:220083. [PMID: 36285441 PMCID: PMC9597168 DOI: 10.1098/rsob.220083] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
MreB is a bacterial protein belonging to the actin superfamily. This protein polymerizes into an antiparallel double-stranded filament that determines cell shape by maintaining cell wall synthesis. Spiroplasma eriocheiris, a helical wall-less bacterium, has five MreB homologous (SpeMreB1-5) that probably contribute to swimming motility. Here, we investigated the structure, ATPase activity and polymerization dynamics of SpeMreB3 and SpeMreB5. SpeMreB3 polymerized into a double-stranded filament with possible antiparallel polarity, while SpeMreB5 formed sheets which contained the antiparallel filament, upon nucleotide binding. SpeMreB3 showed slow Pi release owing to the lack of an amino acid motif conserved in the catalytic centre of MreB family proteins. Our SpeMreB3 crystal structures and analyses of SpeMreB3 and SpeMreB5 variants showed that the amino acid motif probably plays a role in eliminating a nucleophilic water proton during ATP hydrolysis. Sedimentation assays suggest that SpeMreB3 has a lower polymerization activity than SpeMreB5, though their polymerization dynamics are qualitatively similar to those of other actin superfamily proteins, in which pre-ATP hydrolysis and post-Pi release states are unfavourable for them to remain as filaments.
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Affiliation(s)
- Daichi Takahashi
- Graduate School of Science, Osaka Metropolitan University, Osaka, Japan,Graduate School of Science, Osaka City University, Osaka, Japan
| | - Ikuko Fujiwara
- Graduate School of Science, Osaka City University, Osaka, Japan,The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Osaka, Japan,Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Yuya Sasajima
- Graduate School of Science, Osaka Metropolitan University, Osaka, Japan,Graduate School of Science, Osaka City University, Osaka, Japan
| | - Akihiro Narita
- Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Katsumi Imada
- Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Makoto Miyata
- Graduate School of Science, Osaka Metropolitan University, Osaka, Japan,The OMU Advanced Research Center for Natural Science and Technology, Osaka Metropolitan University, Osaka, Japan,Graduate School of Science, Osaka City University, Osaka, Japan,The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Osaka, Japan
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11
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Lucas BA, Zhang K, Loerch S, Grigorieff N. In situ single particle classification reveals distinct 60S maturation intermediates in cells. eLife 2022; 11:79272. [PMID: 36005291 PMCID: PMC9444246 DOI: 10.7554/elife.79272] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 08/24/2022] [Indexed: 11/13/2022] Open
Abstract
Previously we showed that high-resolution template matching can localize ribosomes in two-dimensional electron cryo-microscopy (cryo-EM) images of untilted Mycoplasma pneumoniae cells with high precision (Lucas et al., 2021). Here we show that comparing the signal-to-noise ratio (SNR) observed with 2DTM using different templates relative to the same cellular target can correct for local variation in noise and differentiate related complexes in focused ion beam (FIB)-milled cell sections. We use a maximum likelihood approach to define the probability of each particle belonging to each class, thereby establishing a statistic to describe the confidence of our classification. We apply this method in two contexts to locate and classify related intermediate states of 60S ribosome biogenesis in the Saccharomyces cerevisiae cell nucleus. In the first, we separate the nuclear pre-60S population from the cytoplasmic mature 60S population, using the subcellular localization to validate assignment. In the second, we show that relative 2DTM SNRs can be used to separate mixed populations of nuclear pre-60S that are not visually separable. 2DTM can distinguish related molecular populations without the need to generate 3D reconstructions from the data to be classified, permitting classification even when only a few target particles exist in a cell.
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Affiliation(s)
- Bronwyn A Lucas
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States
| | - Kexin Zhang
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States
| | - Sarah Loerch
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, United States
| | - Nikolaus Grigorieff
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States
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12
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Liu P, Ye Y, Xiang S, Li Y, Zhu C, Chen Z, Hu J, Gen Y, Lou L, Duan X, Zhang J, Gu W. iTRAQ-Based Quantitative Proteomics Analysis Reveals the Invasion Mechanism of Spiroplasma eriocheiris in 3T6 Cells. CURR PROTEOMICS 2022. [DOI: 10.2174/1570164619666220113154423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Background:
Spiroplasma eriocheiris is a novel pathogen of freshwater crustaceans and
is closely related to S. mirum. They have no cell wall and a helical morphology. They have the ability
to infect mammals with an unclear mechanism.
Objective:
In this study, our aim was to investigate the profile of protein expression in 3T6 cells infected
with S. eriocheiris.
Methods:
The proteome of 3T6 cells infected by S. eriocheiris was systematically investigated by
iTRAQ.
Results:
We identified and quantified 4915 proteins, 67 differentially proteins were found, including
30 up-regulated proteins and 37 down-regulated proteins. GO term analysis shows that dysregulation
of adhesion protein , interferon and cytoskeletal regulation are associated with apoptosis. Adhesion
protein Vcam1 and Interferon-induced protein GBP2, Ifit1, TAPBP, CD63 ,Arhgef2 were
up-regulated. A key cytoskeletal regulatory protein, ARHGEF17 was down-regulated. KEGG pathway
analysis showed the NF-kappa B signaling pathway, the MAPK signaling pathway , the Jak-STAT
signaling pathway and NOD-like receptor signaling are closely related to apoptosis in vivo.
Conclusion:
Analysis of the signaling pathways involved in invasion may provide new insights for
understanding the infection mechanisms of S. eriocheiris.
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Affiliation(s)
- Peng Liu
- Institute of Pathogenic Biology, Hengyang Medical College, Institute of Pharmacy and Pharmacology, University of
South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative
Innovation Center for Molecular Target New Drug Study, Hengyang 421001, Hunan, China
| | - Youyuan Ye
- Institute of Pathogenic Biology, Hengyang Medical College, Institute of Pharmacy and Pharmacology, University of
South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative
Innovation Center for Molecular Target New Drug Study, Hengyang 421001, Hunan, China
| | - Shasha Xiang
- Institute of Pathogenic Biology, Hengyang Medical College, Institute of Pharmacy and Pharmacology, University of
South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative
Innovation Center for Molecular Target New Drug Study, Hengyang 421001, Hunan, China
| | - Yuxin Li
- Institute of Pathogenic Biology, Hengyang Medical College, Institute of Pharmacy and Pharmacology, University of
South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative
Innovation Center for Molecular Target New Drug Study, Hengyang 421001, Hunan, China
| | - Chengbin Zhu
- Hengyang Chinese
Medicine Hospital, Hengyang 421001, Hunan, China
| | - Zixu Chen
- Institute of Pathogenic Biology, Hengyang Medical College, Institute of Pharmacy and Pharmacology, University of
South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative
Innovation Center for Molecular Target New Drug Study, Hengyang 421001, Hunan, China
| | - Jie Hu
- Institute of Pathogenic Biology, Hengyang Medical College, Institute of Pharmacy and Pharmacology, University of
South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative
Innovation Center for Molecular Target New Drug Study, Hengyang 421001, Hunan, China
| | - Ye Gen
- Institute of Pathogenic Biology, Hengyang Medical College, Institute of Pharmacy and Pharmacology, University of
South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative
Innovation Center for Molecular Target New Drug Study, Hengyang 421001, Hunan, China
| | - Li Lou
- Institute of Pathogenic Biology, Hengyang Medical College, Institute of Pharmacy and Pharmacology, University of
South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative
Innovation Center for Molecular Target New Drug Study, Hengyang 421001, Hunan, China
| | - Xuqi Duan
- Institute of Pathogenic Biology, Hengyang Medical College, Institute of Pharmacy and Pharmacology, University of
South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative
Innovation Center for Molecular Target New Drug Study, Hengyang 421001, Hunan, China
| | - Juan Zhang
- Institute of Pathogenic Biology, Hengyang Medical College, Institute of Pharmacy and Pharmacology, University of
South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative
Innovation Center for Molecular Target New Drug Study, Hengyang 421001, Hunan, China
| | - Wei Gu
- Jiangsu Key Laboratory
for Microbes & Functional Genomics and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College
of Life Sciences, Nanjing Normal University, No.1 Wenyuan Road, 210046 Nanjing, China
- Co-Innovation Center for
Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, 222005 Jiangsu, China
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13
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Masson F, Pierrat X, Lemaitre B, Persat A. The wall-less bacterium Spiroplasma poulsonii builds a polymeric cytoskeleton composed of interacting MreB isoforms. iScience 2021; 24:103458. [PMID: 34888500 PMCID: PMC8634037 DOI: 10.1016/j.isci.2021.103458] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/03/2021] [Accepted: 11/11/2021] [Indexed: 11/20/2022] Open
Abstract
A rigid cell wall defines the morphology of most bacteria. MreB, a bacterial homologue of actin, plays a major role in coordinating cell wall biogenesis and defining cell shape. Spiroplasma are wall-less bacteria that robustly grow with a characteristic helical shape. Paradoxal to their lack of cell wall, the Spiroplasma genome contains five homologs of MreB (SpMreBs). Here, we investigate the function of SpMreBs in forming a polymeric cytoskeleton. We found that, in vivo, Spiroplasma maintain a high concentration of all MreB isoforms. By leveraging a heterologous expression system that bypasses the poor genetic tractability of Spiroplasma, we found that SpMreBs produced polymeric filaments of various morphologies. We characterized an interaction network between isoforms that regulate filament formation and patterning. Therefore, our results support the hypothesis where combined SpMreB isoforms would form an inner polymeric cytoskeleton in vivo that shapes the cell in a wall-independent manner. The five Spiroplasma MreB isoforms are extremely abundant proteins in vivo Each isoform produces filaments when expressed in a heterologous system SpMreBs form an interaction network that regulates filament length and shape
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Affiliation(s)
- Florent Masson
- Global Health Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
- Corresponding author
| | - Xavier Pierrat
- Global Health Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Bruno Lemaitre
- Global Health Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Alexandre Persat
- Global Health Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
- Corresponding author
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14
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A cryo-TSEM with temperature cycling capability allows deep sublimation of ice to uncover fine structures in thick cells. Sci Rep 2021; 11:21406. [PMID: 34725450 PMCID: PMC8560947 DOI: 10.1038/s41598-021-00979-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 10/18/2021] [Indexed: 11/08/2022] Open
Abstract
The scanning electron microscope (SEM) has been reassembled into a new type of cryo-electron microscope (cryo-TSEM) by installing a new cryo-transfer holder and anti-contamination trap, which allowed simultaneous acquisition of both transmission images (STEM images) and surface images (SEM images) in the frozen state. The ultimate temperatures of the holder and the trap reached − 190 °C and − 210 °C, respectively, by applying a liquid nitrogen slush. The STEM images at 30 kV were comparable to, or superior to, the images acquired with conventional transmission electron microscope (100 kV TEM) in contrast and sharpness. The unroofing method was used to observe membrane cytoskeletons instead of the frozen section and the FIB methods. Deep sublimation of ice surrounding unroofed cells by regulating temperature enabled to emerge intracellular fine structures in thick frozen cells. Hence, fine structures in the vicinity of the cell membrane such as the cytoskeleton, polyribosome chains and endoplasmic reticulum (ER) became visible. The ER was distributed as a wide, flat structure beneath the cell membrane, forming a large spatial network with tubular ER.
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15
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Sasajima Y, Miyata M. Prospects for the Mechanism of Spiroplasma Swimming. Front Microbiol 2021; 12:706426. [PMID: 34512583 PMCID: PMC8432965 DOI: 10.3389/fmicb.2021.706426] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 07/12/2021] [Indexed: 11/18/2022] Open
Abstract
Spiroplasma are helical bacteria that lack a peptidoglycan layer. They are widespread globally as parasites of arthropods and plants. Their infectious processes and survival are most likely supported by their unique swimming system, which is unrelated to well-known bacterial motility systems such as flagella and pili. Spiroplasma swims by switching the left- and right-handed helical cell body alternately from the cell front. The kinks generated by the helicity shift travel down along the cell axis and rotate the cell body posterior to the kink position like a screw, pushing the water backward and propelling the cell body forward. An internal structure called the "ribbon" has been focused to elucidate the mechanisms for the cell helicity formation and swimming. The ribbon is composed of Spiroplasma-specific fibril protein and a bacterial actin, MreB. Here, we propose a model for helicity-switching swimming focusing on the ribbon, in which MreBs generate a force like a bimetallic strip based on ATP energy and switch the handedness of helical fibril filaments. Cooperative changes of these filaments cause helicity to shift down the cell axis. Interestingly, unlike other motility systems, the fibril protein and Spiroplasma MreBs can be traced back to their ancestors. The fibril protein has evolved from methylthioadenosine/S-adenosylhomocysteine (MTA/SAH) nucleosidase, which is essential for growth, and MreBs, which function as a scaffold for peptidoglycan synthesis in walled bacteria.
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Affiliation(s)
- Yuya Sasajima
- Department of Biology, Graduate School of Science, Osaka City University, Osaka, Japan
| | - Makoto Miyata
- Department of Biology, Graduate School of Science, Osaka City University, Osaka, Japan
- The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Osaka, Japan
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16
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Springstein BL, Nürnberg DJ, Weiss GL, Pilhofer M, Stucken K. Structural Determinants and Their Role in Cyanobacterial Morphogenesis. Life (Basel) 2020; 10:E355. [PMID: 33348886 PMCID: PMC7766704 DOI: 10.3390/life10120355] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/04/2020] [Accepted: 12/09/2020] [Indexed: 12/16/2022] Open
Abstract
Cells have to erect and sustain an organized and dynamically adaptable structure for an efficient mode of operation that allows drastic morphological changes during cell growth and cell division. These manifold tasks are complied by the so-called cytoskeleton and its associated proteins. In bacteria, FtsZ and MreB, the bacterial homologs to tubulin and actin, respectively, as well as coiled-coil-rich proteins of intermediate filament (IF)-like function to fulfil these tasks. Despite generally being characterized as Gram-negative, cyanobacteria have a remarkably thick peptidoglycan layer and possess Gram-positive-specific cell division proteins such as SepF and DivIVA-like proteins, besides Gram-negative and cyanobacterial-specific cell division proteins like MinE, SepI, ZipN (Ftn2) and ZipS (Ftn6). The diversity of cellular morphologies and cell growth strategies in cyanobacteria could therefore be the result of additional unidentified structural determinants such as cytoskeletal proteins. In this article, we review the current advances in the understanding of the cyanobacterial cell shape, cell division and cell growth.
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Affiliation(s)
- Benjamin L. Springstein
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Dennis J. Nürnberg
- Department of Physics, Biophysics and Biochemistry of Photosynthetic Organisms, Freie Universität Berlin, 14195 Berlin, Germany;
| | - Gregor L. Weiss
- Department of Biology, Institute of Molecular Biology & Biophysics, ETH Zürich, 8092 Zürich, Switzerland; (G.L.W.); (M.P.)
| | - Martin Pilhofer
- Department of Biology, Institute of Molecular Biology & Biophysics, ETH Zürich, 8092 Zürich, Switzerland; (G.L.W.); (M.P.)
| | - Karina Stucken
- Department of Food Engineering, Universidad de La Serena, La Serena 1720010, Chile;
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17
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Takahashi D, Fujiwara I, Miyata M. Phylogenetic origin and sequence features of MreB from the wall-less swimming bacteria Spiroplasma. Biochem Biophys Res Commun 2020; 533:638-644. [PMID: 33066960 DOI: 10.1016/j.bbrc.2020.09.060] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 09/15/2020] [Indexed: 01/01/2023]
Abstract
Spiroplasma are wall-less bacteria which belong to the phylum Tenericutes that evolved from Firmicutes including Bacillus subtilis. Spiroplasma swim by a mechanism unrelated to widespread bacterial motilities, such as flagellar motility, and caused by helicity switching with kinks traveling along the helical cell body. The swimming force is likely generated by five classes of bacterial actin homolog MreBs (SMreBs 1-5) involved in the helical bone structure. We analyzed sequences of SMreBs to clarify their phylogeny and sequence features. The maximum likelihood method based on around 5000 MreB sequences showed that the phylogenetic tree was divided into several radiations. SMreBs formed a clade adjacent to the radiation of MreBH, an MreB isoform of Firmicutes. Sequence comparisons of SMreBs and Bacillus MreBs were also performed to clarify the features of SMreB. Catalytic glutamic acid and threonine were substituted to aspartic acid and lysine, respectively, in SMreB3. In SMreBs 2 and 4, amino acids involved in inter- and intra-protofilament interactions were significantly different from those in Bacillus MreBs. A membrane-binding region was not identified in most SMreBs 1 and 4 unlike many walled-bacterial MreBs. SMreB5 had a significantly longer C-terminal region than the other MreBs, which possibly forms protein-protein interactions. These features may support the functions responsible for the unique mechanism of Spiroplasma swimming.
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Affiliation(s)
- Daichi Takahashi
- Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka, 558-8585, Japan
| | - Ikuko Fujiwara
- Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka, 558-8585, Japan; The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Sumiyoshi-ku, Osaka, 558-8585, Japan
| | - Makoto Miyata
- Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka, 558-8585, Japan; The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Sumiyoshi-ku, Osaka, 558-8585, Japan.
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18
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Harne S, Duret S, Pande V, Bapat M, Béven L, Gayathri P. MreB5 Is a Determinant of Rod-to-Helical Transition in the Cell-Wall-less Bacterium Spiroplasma. Curr Biol 2020; 30:4753-4762.e7. [PMID: 32976813 DOI: 10.1016/j.cub.2020.08.093] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/05/2020] [Accepted: 08/26/2020] [Indexed: 12/22/2022]
Abstract
In most rod-shaped bacteria, the spatial coordination of cell wall synthesis machinery by MreBs is the main theme for shape determination and maintenance in cell-walled bacteria [1-9]. However, how rod or spiral shapes are achieved and maintained in cell-wall-less bacteria is currently unknown. Spiroplasma, a helical Mollicute that lacks cell wall synthesis genes, encodes five MreB paralogs and a unique cytoskeletal protein fibril [10, 11]. Here, we show that MreB5, one of the five MreB paralogs, contributes to cell elongation and is essential for the transition from rod-to-helical shape in Spiroplasma. Comparative genomic and proteomic characterization of a helical and motile wild-type Spiroplasma strain and a non-helical, non-motile natural variant helped delineate the specific roles of MreB5. Moreover, complementation of the non-helical strain with MreB5 restored its helical shape and motility by a kink-based mechanism described for Spiroplasma [12]. Earlier studies had proposed that length changes in fibril filaments are responsible for the change in handedness of the helical cell and kink propagation during motility [13]. Through structural and biochemical characterization, we identify that MreB5 exists as antiparallel double protofilaments that interact with fibril and the membrane, and thus potentially assists in kink propagation. In summary, our study provides direct experimental evidence for MreB in maintaining cell length, helical shape, and motility-revealing the role of MreB in sculpting the cell in the absence of a cell wall.
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Affiliation(s)
- Shrikant Harne
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
| | - Sybille Duret
- INRAE, University of Bordeaux, UMR 1332 BFP, Villenave d'Ornon, Bordeaux, France
| | - Vani Pande
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
| | - Mrinmayee Bapat
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
| | - Laure Béven
- INRAE, University of Bordeaux, UMR 1332 BFP, Villenave d'Ornon, Bordeaux, France.
| | - Pananghat Gayathri
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
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19
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Harne S, Gayathri P, Béven L. Exploring Spiroplasma Biology: Opportunities and Challenges. Front Microbiol 2020; 11:589279. [PMID: 33193251 PMCID: PMC7609405 DOI: 10.3389/fmicb.2020.589279] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 09/28/2020] [Indexed: 11/13/2022] Open
Abstract
Spiroplasmas are cell-wall-deficient helical bacteria belonging to the class Mollicutes. Their ability to maintain a helical shape in the absence of cell wall and their motility in the absence of external appendages have attracted attention from the scientific community for a long time. In this review we compare and contrast motility, shape determination and cytokinesis mechanisms of Spiroplasma with those of other Mollicutes and cell-walled bacteria. The current models for rod-shape determination and cytokinesis in cell-walled bacteria propose a prominent role for the cell wall synthesis machinery. These models also involve the cooperation of the actin-like protein MreB and FtsZ, the bacterial homolog of tubulin. However the exact role of the cytoskeletal proteins is still under much debate. Spiroplasma possess MreBs, exhibit a rod-shape dependent helical morphology, and divide by an FtsZ-dependent mechanism. Hence, spiroplasmas represent model organisms for deciphering the roles of MreBs and FtsZ in fundamental mechanisms of non-spherical shape determination and cytokinesis in bacteria, in the absence of a cell wall. Identification of components implicated in these processes and deciphering their functions would require genetic experiments. Challenges in genetic manipulations in spiroplasmas are a major bottleneck in understanding their biology. We discuss advancements in genome sequencing, gene editing technologies, super-resolution microscopy and electron cryomicroscopy and tomography, which can be employed for addressing long-standing questions related to Spiroplasma biology.
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Affiliation(s)
- Shrikant Harne
- Indian Institute of Science Education and Research, Pune, India
| | | | - Laure Béven
- INRAE, UMR 1332, Biologie du Fruit et Pathologie, University of Bordeaux, Bordeaux, France
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20
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Abstract
Correlative light and electron microscopy (CLEM) combines the strengths of light microscopy (LM) and electron microscopy (EM) to pin-point and visualize cellular or macromolecular structures. However, there are many different imaging modalities that can be combined in a CLEM workflow, creating a vast number of combinations that can overwhelm new-comers to the field. Here, we offer a conceptual framework to help guide the decision-making process for choosing the CLEM workflow that can best address your research question, based on the answer to five questions.
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21
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Böhning J, Bharat TAM. Towards high-throughput in situ structural biology using electron cryotomography. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 160:97-103. [PMID: 32579969 DOI: 10.1016/j.pbiomolbio.2020.05.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 05/21/2020] [Accepted: 05/27/2020] [Indexed: 01/11/2023]
Abstract
Electron cryotomography is a rapidly evolving method for imaging macromolecules directly within the native environment of cells and tissues. Combined with sub-tomogram averaging, it allows structural and cell biologists to obtain sub-nanometre resolution structures in situ. However, low throughput in cryo-ET sample preparation and data acquisition, as well as difficulties in target localisation and sub-tomogram averaging image processing, limit its widespread usability. In this review, we discuss new advances in the field that address these throughput and technical problems. We focus on recent efforts made to resolve issues in sample thinning, improvement in data collection speed at the microscope, strategies for localisation of macromolecules using correlated light and electron microscopy and advancements made to improve resolution in sub-tomogram averaging. These advances will considerably decrease the amount of time and effort required for cryo-ET and sub-tomogram averaging, ushering in a new era of structural biology where in situ macromolecular structure determination will be routine.
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Affiliation(s)
- Jan Böhning
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, United Kingdom; Central Oxford Structural Microscopy and Imaging Centre, South Parks Road, Oxford OX1 3RE, United Kingdom
| | - Tanmay A M Bharat
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, United Kingdom; Central Oxford Structural Microscopy and Imaging Centre, South Parks Road, Oxford OX1 3RE, United Kingdom.
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22
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Coexistence of Two Chiral Helices Produces Kink Translation in Spiroplasma Swimming. J Bacteriol 2020; 202:JB.00735-19. [PMID: 32041794 DOI: 10.1128/jb.00735-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 01/31/2020] [Indexed: 12/23/2022] Open
Abstract
The mechanism underlying Spiroplasma swimming is an enigma. This small bacterium possesses two helical shapes with opposite-handedness at a time, and the boundary between them, called a kink, travels down, possibly accompanying the dual rotations of these physically connected helical structures, without any rotary motors such as flagella. Although the outline of dynamics and structural basis has been proposed, the underlying cause to explain the kink translation is missing. We here demonstrated that the cell morphology of Spiroplasma eriocheiris was fixed at the right-handed helix after motility was stopped by the addition of carbonyl cyanide 3-chlorophenylhydrazone (CCCP), and the preferential state was transformed to the other-handedness by the trigger of light irradiation. This process coupled with the generation and propagation of the artificial kink, presumably without any energy input through biological motors. These findings indicate that the coexistence of two chiral helices is sufficient to propagate the kink and thus to propel the cell body.IMPORTANCE Many swimming bacteria generate a propulsion force by rotating helical filaments like a propeller. However, the nonflagellated bacteria Spiroplasma spp. swim without the use of the appendages. The tiny wall-less bacteria possess two chiral helices at a time, and the boundary called a kink travels down, possibly accompanying the dual rotations of the helices. To solve this enigma, we developed an assay to determine the handedness of the body helices at the single-wind level, and demonstrated that the coexistence of body helices triggers the translation of the kink and that the cell body moves by the resultant cell bend propagation. This finding provides us a totally new aspect of bacterial motility, where the body functions as a transformable screw to propel itself forward.
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23
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Refined Mechanism of Mycoplasma mobile Gliding Based on Structure, ATPase Activity, and Sialic Acid Binding of Machinery. mBio 2019; 10:mBio.02846-19. [PMID: 31874918 PMCID: PMC6935860 DOI: 10.1128/mbio.02846-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Mycoplasma mobile, a fish pathogen, glides on solid surfaces by repeated catch, pull, and release of sialylated oligosaccharides by a unique mechanism based on ATP energy. The gliding machinery is composed of huge surface proteins and an internal "jellyfish"-like structure. Here, we elucidated the detailed three-dimensional structures of the machinery by electron cryotomography. The internal "tentacle"-like structure hydrolyzed ATP, which was consistent with the fact that the paralogs of the α- and β-subunits of F1-ATPase are at the tentacle structure. The electron microscopy suggested conformational changes of the tentacle structure depending on the presence of ATP analogs. The gliding machinery was isolated and showed that the binding activity to sialylated oligosaccharide was higher in the presence of ADP than in the presence of ATP. Based on these results, we proposed a model to explain the mechanism of M. mobile gliding.IMPORTANCE The genus Mycoplasma is made up of the smallest parasitic and sometimes commensal bacteria; Mycoplasma pneumoniae, which causes human "walking pneumonia," is representative. More than ten Mycoplasma species glide on host tissues by novel mechanisms, always in the direction of the distal side of the machinery. Mycoplasma mobile, the fastest species in the genus, catches, pulls, and releases sialylated oligosaccharides (SOs), the carbohydrate molecules also targeted by influenza viruses, by means of a specific receptor and using ATP hydrolysis for energy. Here, the architecture of the gliding machinery was visualized three dimensionally by electron cryotomography (ECT), and changes in the structure and binding activity coupled to ATP hydrolysis were discovered. Based on the results, a refined mechanism was proposed for this unique motility.
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24
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Abstract
Chirality is a recurrent theme in the study of biological systems, in which active processes are driven by the internal conversion of chemical energy into work. Bacterial flagella, actomyosin filaments, and microtubule bundles are active systems that are also intrinsically chiral. Despite some exploratory attempt to capture the relations between chirality and motility, many features of intrinsically chiral systems still need to be explored and explained. To address this gap in knowledge, here we study the effects of internal active forces and torques on a 3-dimensional (3D) droplet of cholesteric liquid crystal (CLC) embedded in an isotropic liquid. We consider tangential anchoring of the liquid crystal director at the droplet surface. Contrary to what happens in nematics, where moderate extensile activity leads to droplet rotation, cholesteric active droplets exhibit more complex and variegated behaviors. We find that extensile force dipole activity stabilizes complex defect configurations, in which orbiting dynamics couples to thermodynamic chirality to propel screw-like droplet motion. Instead, dipolar torque activity may either tighten or unwind the cholesteric helix and if tuned, can power rotations with an oscillatory angular velocity of 0 mean.
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25
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Toro-Nahuelpan M, Giacomelli G, Raschdorf O, Borg S, Plitzko JM, Bramkamp M, Schüler D, Müller FD. MamY is a membrane-bound protein that aligns magnetosomes and the motility axis of helical magnetotactic bacteria. Nat Microbiol 2019; 4:1978-1989. [PMID: 31358981 PMCID: PMC6817358 DOI: 10.1038/s41564-019-0512-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 06/11/2019] [Indexed: 11/09/2022]
Abstract
To navigate within the geomagnetic field, magnetotactic bacteria synthesize magnetosomes, which are unique organelles consisting of membrane-enveloped magnetite nanocrystals. In magnetotactic spirilla, magnetosomes become actively organized into chains by the filament-forming actin-like MamK and the adaptor protein MamJ, thereby assembling a magnetic dipole much like a compass needle. However, in Magnetospirillum gryphiswaldense, discontinuous chains are still formed in the absence of MamK. Moreover, these fragmented chains persist in a straight conformation indicating undiscovered structural determinants able to accommodate a bar magnet-like magnetoreceptor in a helical bacterium. Here, we identify MamY, a membrane-bound protein that generates a sophisticated mechanical scaffold for magnetosomes. MamY localizes linearly along the positive inner cell curvature (the geodetic cell axis), probably by self-interaction and curvature sensing. In a mamY deletion mutant, magnetosome chains detach from the geodetic axis and fail to accommodate a straight conformation coinciding with reduced cellular magnetic orientation. Codeletion of mamKY completely abolishes chain formation, whereas on synthetic tethering of magnetosomes to MamY, the chain configuration is regained, emphasizing the structural properties of the protein. Our results suggest MamY is membrane-anchored mechanical scaffold that is essential to align the motility axis of magnetotactic spirilla with their magnetic moment vector and to perfectly reconcile magnetoreception with swimming direction.
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Affiliation(s)
- Mauricio Toro-Nahuelpan
- Department of Microbiology, University of Bayreuth, Bayreuth, Germany.,Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Planegg-Martinsried, Germany.,European Molecular Biology Laboratory, Heidelberg, Germany
| | - Giacomo Giacomelli
- Department of Biology I, Ludwig-Maximilian-University Munich, Planegg-Martinsried, Germany
| | - Oliver Raschdorf
- Department of Microbiology, University of Bayreuth, Bayreuth, Germany.,Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Planegg-Martinsried, Germany.,ThermoFisher Scientific (formerly FEI Company), Eindhoven, the Netherlands
| | - Sarah Borg
- Department of Microbiology, University of Bayreuth, Bayreuth, Germany.,Bundeswehr Institute of Microbiology, Bundeswehr, Munich, Germany
| | - Jürgen M Plitzko
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Planegg-Martinsried, Germany
| | - Marc Bramkamp
- Department of Biology I, Ludwig-Maximilian-University Munich, Planegg-Martinsried, Germany
| | - Dirk Schüler
- Department of Microbiology, University of Bayreuth, Bayreuth, Germany
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26
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Roth J, Koch MD, Rohrbach A. Dynamics of a Protein Chain Motor Driving Helical Bacteria under Stress. Biophys J 2019; 114:1955-1969. [PMID: 29694872 DOI: 10.1016/j.bpj.2018.02.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 02/27/2018] [Accepted: 02/28/2018] [Indexed: 12/21/2022] Open
Abstract
The wall-less, helical bacterial genus Spiroplasma has a unique propulsion system; it is not driven by propeller-like flagella but by a membrane-bound, cytoplasmic, linear motor that consists of a contractile chain of identical proteins spanning the entire cell length. By a coordinated spread of conformational changes of the proteins, kinks propagate in pairs along the cell body. However, the mechanisms for the initiation or delay of kinks and their coordinated spread remain unclear. Here, we show how we manipulate the initiation of kinks, their propagation velocities, and the time between two kinks for a single cell trapped in an optical line potential. By interferometric three-dimensional shape tracking, we measured the cells' deformations in response to various external stress situations. We observed a significant dependency of force generation on the cells' local ligand concentrations (likely ATP) and ligand hydrolysis, which we altered in different ways. We developed a mechanistic, mathematical model based on Kramer's rates, describing the subsequent cooperative and conformational switching of the chain's proteins. The model reproduces our experimental observations and can explain deformation characteristics even when the motor is driven to its extreme. Nature has invented a set of minimalistic mechanical driving concepts. To understand or even rebuild them, it is essential to reveal the molecular mechanisms of such protein chain motors, which need only two components-coupled proteins and ligands-to function.
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Affiliation(s)
- Julian Roth
- Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany
| | - Matthias D Koch
- Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany; Princeton University, Princeton, New Jersey
| | - Alexander Rohrbach
- Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany.
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27
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Liu P, Du J, Zhang J, Wang J, Gu W, Wang W, Meng Q. The structural and proteomic analysis of Spiroplasma eriocheiris in response to colchicine. Sci Rep 2018; 8:8577. [PMID: 29872058 PMCID: PMC5988712 DOI: 10.1038/s41598-018-26614-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 04/23/2018] [Indexed: 11/18/2022] Open
Abstract
Spiroplasma eriocheiris, a pathogen that causes mass mortality of Chinese mitten crab Eriocheir sinensis, is a wall less bacteria and belongs to the Mollicutes. This study was designed to investigate the effects of colchicine on S. eriocheiris growth, cell morphology, and proteins expression. We found that in the presence of colchicine, the spiroplasma cells lost their helicity, and the length of the cells in the experimental group was longer than that of the control. With varying concentrations of the colchicine treatment, the total time to achieve a stationary phase of the spiroplasma was increased, and the cell population was decreased. The virulence ability of S. eriocheiris to E. sinensis was effectively reduced in the presence of colchicine. To expound the toxical mechanism of colchicine on S. eriocheiris, 208 differentially expressed proteins of S. eriocheiris were reliably quantified by iTRAQ analysis, including 77 up-regulated proteins and 131 down-regulated proteins. Especially, FtsY, putative Spiralin, and NADH oxidase were down-regulated. F0F1 ATP synthase subunit delta, ParB, DNABs, and NAD(FAD)-dependent dehydrogenase were up-regulated. A qRT-PCR was conducted to detect 7 expressed genes from the iTRAQ results during the incubation. The qRT-PCR results were consistent with the iTRAQ results. All of our results indicate that colchicine have a strong impact on the cell morphology and cellular metabolism of S. eriocheiris.
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Affiliation(s)
- Peng Liu
- Jiangsu Key Laboratory for Microbes & Functional Genomics and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, China.,Department of Biology, College of Pharmacy and Biological Sciences, University of South China, Hengyang, 421001, P.R. China.,Hunan Province cooperative innovation Center for Molecular Target New Drug Study, Hengyang, 421001, P.R. China
| | - Jie Du
- Jiangsu Key Laboratory for Microbes & Functional Genomics and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, China
| | - Jia Zhang
- Jiangsu Key Laboratory for Microbes & Functional Genomics and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, China
| | - Jian Wang
- Jiangsu Key Laboratory for Microbes & Functional Genomics and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, China
| | - Wei Gu
- Jiangsu Key Laboratory for Microbes & Functional Genomics and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, China
| | - Wen Wang
- Jiangsu Key Laboratory for Microbes & Functional Genomics and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, China
| | - Qingguo Meng
- Jiangsu Key Laboratory for Microbes & Functional Genomics and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, China.
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Fünfhaus A, Ebeling J, Genersch E. Bacterial pathogens of bees. CURRENT OPINION IN INSECT SCIENCE 2018; 26:89-96. [PMID: 29764667 DOI: 10.1016/j.cois.2018.02.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 01/09/2018] [Accepted: 02/02/2018] [Indexed: 05/09/2023]
Abstract
Pollination is an indispensable ecosystem service provided by many insects, especially by wild and managed bee species. Hence, reports on large scale honey bee colony losses and on population declines of many wild bees were alarming and resulted in increased awareness of the importance of bee health and increased interest in bee pathogens. To serve this interest, this review will give a comprehensive overview on bacterial bee pathogens by covering not only the famous pathogens (Paenibacillus larvae, Melissococcus plutonius), but also the orphan pathogens which have largely been neglected by the scientific community so far (spiroplasmas) and the pathogens which were only recently discovered as being pathogenic to bees (Serratia marcescens, Lysinibacillus sphaericus).
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Affiliation(s)
- Anne Fünfhaus
- Institute for Bee Research, Department of Molecular Microbiology and Bee Diseases, Friedrich-Engels-Str. 32, 16540 Hohen Neuendorf, Germany
| | - Julia Ebeling
- Institute for Bee Research, Department of Molecular Microbiology and Bee Diseases, Friedrich-Engels-Str. 32, 16540 Hohen Neuendorf, Germany
| | - Elke Genersch
- Institute for Bee Research, Department of Molecular Microbiology and Bee Diseases, Friedrich-Engels-Str. 32, 16540 Hohen Neuendorf, Germany; Freie Universität Berlin, Fachbereich Veterinärmedizin, Institut für Mikrobiologie und Tierseuchen, Robert-von-Ostertag-Str. 7-13, 14163 Berlin, Germany.
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Li S, Ji G, Shi Y, Klausen LH, Niu T, Wang S, Huang X, Ding W, Zhang X, Dong M, Xu W, Sun F. High-vacuum optical platform for cryo-CLEM (HOPE): A new solution for non-integrated multiscale correlative light and electron microscopy. J Struct Biol 2018; 201:63-75. [PMID: 29113848 DOI: 10.1016/j.jsb.2017.11.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 10/28/2017] [Accepted: 11/03/2017] [Indexed: 12/28/2022]
Abstract
Cryo-correlative light and electron microscopy (cryo-CLEM) offers a unique way to analyze the high-resolution structural information of cryo-vitrified specimen by cryo-electron microscopy (cryo-EM) with the guide of the search for unique events by cryo-fluorescence microscopy (cryo-FM). To achieve cryo-FM, a trade-off must be made between the temperature and performance of objective lens. The temperature of specimen should be kept below devitrification while the distance between the objective lens and specimen should be short enough for high resolution imaging. Although special objective lens was designed in many current cryo-FM approaches, the unavoided frosting and ice contamination are still affecting the efficiency of cryo-CLEM. In addition, the correlation accuracy between cryo-FM and cryo-EM would be reduced during the current specimen transfer procedure. Here, we report an improved cryo-CLEM technique (high-vacuum optical platform for cryo-CLEM, HOPE) based on a high-vacuum optical stage and a commercial cryo-EM holder. The HOPE stage comprises of a special adapter to suit the cryo-EM holder and a high-vacuum chamber with an anti-contamination system. It provides a clean and enduring environment for cryo specimen, while the normal dry objective lens in room temperature can be used via the optical windows. The 'touch-free' specimen transfer via cryo-EM holder allows least specimen deformation and thus maximizes the correlation accuracy between cryo-FM and cryo-EM. Besides, we developed a software to perform semi-automatic cryo-EM acquisition of the target region localized by cryo-FM. Our work provides a new solution for cryo-CLEM and can be adapted for different commercial fluorescence microscope and electron microscope.
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Affiliation(s)
- Shuoguo Li
- Center for Biological Imaging, Core Facilities for Protein Science, Institute of Biophysics, CAS, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Gang Ji
- Center for Biological Imaging, Core Facilities for Protein Science, Institute of Biophysics, CAS, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
| | - Yang Shi
- University of Chinese Academy of Sciences, Beijing, China; National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Lasse Hyldgaard Klausen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Tongxin Niu
- Center for Biological Imaging, Core Facilities for Protein Science, Institute of Biophysics, CAS, Beijing, China; University of Chinese Academy of Sciences, Beijing, China; National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Shengliu Wang
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaojun Huang
- Center for Biological Imaging, Core Facilities for Protein Science, Institute of Biophysics, CAS, Beijing, China
| | - Wei Ding
- Center for Biological Imaging, Core Facilities for Protein Science, Institute of Biophysics, CAS, Beijing, China
| | - Xiang Zhang
- University of Chinese Academy of Sciences, Beijing, China
| | - Mingdong Dong
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Wei Xu
- Center for Biological Imaging, Core Facilities for Protein Science, Institute of Biophysics, CAS, Beijing, China
| | - Fei Sun
- Center for Biological Imaging, Core Facilities for Protein Science, Institute of Biophysics, CAS, Beijing, China; University of Chinese Academy of Sciences, Beijing, China; National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
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Engelhardt H, Bollschweiler D. Cryo-Electron Microscopy of Extremely Halophilic Microbes. J Microbiol Methods 2018. [DOI: 10.1016/bs.mim.2018.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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31
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Sanders T, Dwyer C. Subsampling and inpainting approaches for electron tomography. Ultramicroscopy 2017; 182:292-302. [PMID: 28797951 DOI: 10.1016/j.ultramic.2017.07.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 07/28/2017] [Accepted: 07/30/2017] [Indexed: 10/19/2022]
Abstract
With the aim of addressing the issue of sample damage during electron tomography data acquisition, we propose a number of new reconstruction strategies based on subsampling (which uses only a subset of a full image) and inpainting (recovery of a full image from subsampled one). We point out that the total-variation (TV) inpainting model commonly used to inpaint subsampled images may be inappropriate for 2D projection images of typical TEM specimens. Thus, we propose higher-order TV (HOTV) inpainting, which accommodates the fact that projection images may be inherently smooth, as a more suitable image inpainting scheme. We also describe how the HOTV method can be extended to 3D, a scheme which makes use of both image data and sinogram data. Additionally, we propose gradient subsampling as a more efficient scheme than random subsampling. We make a rigorous comparison of our proposed new reconstruction schemes with existing ones. The new schemes are demonstrated to perform better than or as well as existing schemes, and we show that they outperform existing schemes at low subsampling rates.
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Affiliation(s)
- Toby Sanders
- School Of Mathematical and Statistical Sciences, Arizona State University, Tempe, Arizona 85287-1804, USA.
| | - Christian Dwyer
- Department of Physics, Arizona State University, Tempe, Arizona 85287-1504, USA
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Wagner J, Schaffer M, Fernández-Busnadiego R. Cryo-electron tomography-the cell biology that came in from the cold. FEBS Lett 2017; 591:2520-2533. [PMID: 28726246 DOI: 10.1002/1873-3468.12757] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 06/26/2017] [Accepted: 07/14/2017] [Indexed: 12/27/2022]
Abstract
Cryo-electron tomography (cryo-ET) provides high-resolution 3D views into cells pristinely preserved by vitrification. Recent technical advances such as direct electron detectors, the Volta phase plate and cryo-focused ion beam milling have dramatically pushed image quality and expanded the range of cryo-ET applications. Cryo-ET not only allows mapping the positions and interactions of macromolecules within their intact cellular context, but can also reveal their in situ structure at increasing resolution. Here, we review how recent work using cutting-edge cryo-ET technologies is starting to provide fresh views into different aspects of cellular biology at an unprecedented level of detail. We anticipate that these developments will soon make cryo-ET a fundamental technique in cell biology.
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Terahara N, Tulum I, Miyata M. Transformation of crustacean pathogenic bacterium Spiroplasma eriocheiris and expression of yellow fluorescent protein. Biochem Biophys Res Commun 2017; 487:488-493. [PMID: 28363870 DOI: 10.1016/j.bbrc.2017.03.144] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 03/26/2017] [Indexed: 10/19/2022]
Abstract
Spiroplasma eriocheiris, the cause of crab trembling disease, is a wall-less bacterium, related to Mycoplasmas, measuring 2.0-10.0 μm long. It features a helical cell shape and a unique swimming mechanism that does not use flagella; instead, it moves by switching the cell helicity at a kink traveling from the front to the tail. S. eriocheiris seems to use a novel chemotactic system that is based on the frequency of reversal swimming behaviors rather than the conventional two-component system, which is generally essential for bacterial chemotaxis. To identify the genes involved in these novel mechanisms, we developed a transformation system by using oriC plasmid harboring the tetracycline resistant gene, tetM, which is under the control of a strong promoter for an abundant protein, elongation factor-Tu. The transformation efficiency achieved was 1.6 × 10-5 colony forming unit (CFU) for 1 μg DNA, enabling the expression of the enhanced yellow fluorescent protein (EYFP).
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Affiliation(s)
- Natsuho Terahara
- Department of Biology, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
| | - Isil Tulum
- Department of Biology, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan; The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan.
| | - Makoto Miyata
- Department of Biology, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan; The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan.
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Liu P, Zheng H, Meng Q, Terahara N, Gu W, Wang S, Zhao G, Nakane D, Wang W, Miyata M. Chemotaxis without Conventional Two-Component System, Based on Cell Polarity and Aerobic Conditions in Helicity-Switching Swimming of Spiroplasma eriocheiris. Front Microbiol 2017; 8:58. [PMID: 28217108 PMCID: PMC5289999 DOI: 10.3389/fmicb.2017.00058] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 01/09/2017] [Indexed: 11/13/2022] Open
Abstract
Spiroplasma eriocheiris is a pathogen that causes mass mortality in Chinese mitten crab, Eriocheir sinensis. S. eriocheiris causes tremor disease and infects almost all of the artificial breeding crustaceans, resulting in disastrous effects on the aquaculture economy in China. S. eriocheiris is a wall-less helical bacterium, measuring 2.0 to 10.0 μm long, and can swim up to 5 μm per second in a viscous medium without flagella by switching the cell helicity at a kink traveling from the front to the tail. In this study, we showed that S. eriocheiris performs chemotaxis without the conventional two-component system, a system commonly found in bacterial chemotaxis. The chemotaxis of S. eriocheiris was observed more clearly when the cells were cultivated under anaerobic conditions. The cells were polarized as evidenced by a tip structure, swimming in the direction of the tip, and were shown to reverse their swimming direction in response to attractants. Triton X-100 treatment revealed the internal structure, a dumbbell-shaped core in the tip that is connected by a flat ribbon, which traces the shortest line in the helical cell shape from the tip to the other pole. Sixteen proteins were identified as the components of the internal structure by mass spectrometry, including Fibril protein and four types of MreB proteins.
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Affiliation(s)
- Peng Liu
- Jiangsu Key Laboratory for Biodiversity and Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal UniversityJiangsu, China; Department of Biology, Graduate School of Science, Osaka City UniversityOsaka, Japan
| | - Huajun Zheng
- Shanghai-MOST Key Laboratory of Health and Disease Genomics, Chinese National Human Genome Center at Shanghai Shanghai, China
| | - Qingguo Meng
- Jiangsu Key Laboratory for Biodiversity and Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University Jiangsu, China
| | - Natsuho Terahara
- Department of Biology, Graduate School of Science, Osaka City University Osaka, Japan
| | - Wei Gu
- Jiangsu Key Laboratory for Biodiversity and Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University Jiangsu, China
| | - Shengyue Wang
- Shanghai-MOST Key Laboratory of Health and Disease Genomics, Chinese National Human Genome Center at Shanghai Shanghai, China
| | - Guoping Zhao
- Shanghai-MOST Key Laboratory of Health and Disease Genomics, Chinese National Human Genome Center at Shanghai Shanghai, China
| | - Daisuke Nakane
- Department of Physics, Gakushuin University Tokyo, Japan
| | - Wen Wang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University Jiangsu, China
| | - Makoto Miyata
- Department of Biology, Graduate School of Science, Osaka City UniversityOsaka, Japan; The OCU Advanced Research Institute for Natural Science and Technology, Osaka City UniversityOsaka, Japan
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35
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Wada H. Structural mechanics and helical geometry of thin elastic composites. SOFT MATTER 2016; 12:7386-7397. [PMID: 27510457 DOI: 10.1039/c6sm01090c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Helices are ubiquitous in nature, and helical shape transition is often observed in residually stressed bodies, such as composites, wherein materials with different mechanical properties are glued firmly together to form a whole body. Inspired by a variety of biological examples, the basic physical mechanism responsible for the emergence of twisting and bending in such thin composite structures has been extensively studied. Here, we propose a simplified analytical model wherein a slender membrane tube undergoes a helical transition driven by the contraction of an elastic ribbon bound to the membrane surface. We analytically predict the curvature and twist of an emergent helix as functions of differential strains and elastic moduli, which are confirmed by our numerical simulations. Our results may help understand shapes observed in different biological systems, such as spiral bacteria, and could be applied to novel designs of soft machines and robots.
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Affiliation(s)
- Hirofumi Wada
- Department of Physics, Ritsumeikan University, Kusatsu, 525-8577 Shiga, Japan.
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Makihara M, Watanabe T, Usukura E, Kaibuchi K, Narita A, Tanaka N, Usukura J. A new approach for the direct visualization of the membrane cytoskeleton in cryo-electron microscopy: a comparative study with freeze-etching electron microscopy. Microscopy (Oxf) 2016; 65:488-498. [PMID: 27587510 DOI: 10.1093/jmicro/dfw037] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 08/10/2016] [Indexed: 12/17/2022] Open
Abstract
An improved unroofing method consisting of tearing off the cell membrane using an adhesive electron microscopy (EM) grid instead of vitreous ice sectioning (cryo-sectioning) has enabled us to panoramically view the membrane cytoskeleton in its native state with extremely high contrast. Grids pre-treated with Alcian blue were placed on cells, and a portion of the dorsal plasma membrane was transferred onto the grid, which was then floated in buffer solution. These membrane fragments contained sufficient cytoskeleton and were of suitable thickness for observation by cryo-EM. Many actin filaments and microtubules were clearly observed on the cytoplasmic surface of the plasma membrane with extremely high contrast because the soluble components of the cytoplasm flowed out and broke away from the cells. Actin filaments extended in all directions in a smooth contour with little branching. Microtubules spread out as far as 3 µm or more while winding gently in their native state. Upon fixation with 1% glutaraldehyde, however, the microtubules became straight and fragmented. Cryo-EM revealed for the first time a smooth endoplasmic reticulum network beneath the cell membrane in native cells. Clathrin coats and caveolae were also observed on the cytoplasmic surface of the plasma membrane, similar to those seen using freeze-etching replica EM (freeze-etching EM). Unroofing was also useful for immuno-labelling in cryo-EM. Antibody-labelled IQGAP1, one of the effector proteins facilitating the formation of actin filament networks, was localized alongside actin filaments. Freeze-etching EM confirmed the morphological findings of cryo-EM.
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Affiliation(s)
| | - Takashi Watanabe
- Department of Cell Pharmacology, Graduate School of Medicine, Nagoya University, Nagoya 466-8550
| | - Eiji Usukura
- Structural Biology Research Center, Nagoya University, Nagoya 464-8603
| | - Kozo Kaibuchi
- Department of Cell Pharmacology, Graduate School of Medicine, Nagoya University, Nagoya 466-8550
| | - Akihiro Narita
- Structural Biology Research Center, Nagoya University, Nagoya 464-8603
| | - Nobuo Tanaka
- Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya 464-8603, Japan
| | - Jiro Usukura
- Structural Biology Research Center, Nagoya University, Nagoya 464-8603
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Meng Q, Liu P, Wang J, Wang Y, Hou L, Gu W, Wang W. Systematic analysis of the lysine acetylome of the pathogenic bacterium Spiroplasma eriocheiris reveals acetylated proteins related to metabolism and helical structure. J Proteomics 2016; 148:159-69. [PMID: 27498276 DOI: 10.1016/j.jprot.2016.08.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 07/28/2016] [Accepted: 08/02/2016] [Indexed: 10/21/2022]
Abstract
UNLABELLED Post-translational modifications such as acetylation are an essential regulatory mechanism of protein function. Spiroplasma eriocheiris, with no cell wall and a helical structure, is a novel pathogen of freshwater crustacean. There is no other evidence of acylation (such as succinylation and propionylation) except acetylation genes in S. eriocheiris concise genome. So the acetylation may play an important role in S. eriocheiris. Here, we conducted the first lysine acetylome in S. eriocheiris. We identified 2567 lysine acetylation sites in 555 proteins, which account for 44.69% of the total proteins in this bacterium. To date, this is the highest ratio of acetylated proteins that have been identified in bacteria. Fifteen types of acetylated peptide sequence motifs were revealed from the acetylome. Forty-five lysine-acetylated proteins showed homology with acetylated proteins previously identified from Escherichia coli, Vibrio parahemolyticus and Mycobacterium tuberculosis. Notably, most proteins in glycolysis and all proteins in the arginine deiminase system were acetylated. Meanwhile, the cell skeleton proteins (Fibril and Mrebs) were all acetylated the observed acetylation also played an important role in cell skeleton formation. The results imply previously unreported hidden layers of post-translational regulation in lysine acetylation that define the functional state of Spiroplasma. BIOLOGICAL SIGNIFICANCE This is the first time to analyze PTM of Spiroplasma. This is the highest ratio of acetylated proteins that have been identified in bacteria. S. eriocheiris lysine acetylome reveals acetylated proteins related to metabolism and helical structure. These data provide an important resource to elucidate the role of acetylation in Spiroplasma cellular physiology.
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Affiliation(s)
- Qingguo Meng
- Jiangsu Key Laboratory for Biodiversity & Biotechnology, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China; Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China
| | - Peng Liu
- Jiangsu Key Laboratory for Biodiversity & Biotechnology, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China; Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China
| | - Jian Wang
- Jiangsu Key Laboratory for Biodiversity & Biotechnology, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China; Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China
| | - Yinghui Wang
- Jiangsu Key Laboratory for Biodiversity & Biotechnology, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China; Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China
| | - Libo Hou
- Jiangsu Key Laboratory for Biodiversity & Biotechnology, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China; Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China
| | - Wei Gu
- Jiangsu Key Laboratory for Biodiversity & Biotechnology, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China; Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China
| | - Wen Wang
- Jiangsu Key Laboratory for Biodiversity & Biotechnology, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China; Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China.
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Miyata M, Hamaguchi T. Integrated Information and Prospects for Gliding Mechanism of the Pathogenic Bacterium Mycoplasma pneumoniae. Front Microbiol 2016; 7:960. [PMID: 27446003 PMCID: PMC4923136 DOI: 10.3389/fmicb.2016.00960] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Accepted: 06/02/2016] [Indexed: 01/21/2023] Open
Abstract
Mycoplasma pneumoniae forms a membrane protrusion at a cell pole and is known to adhere to solid surfaces, including animal cells, and can glide on these surfaces with a speed up to 1 μm per second. Notably, gliding appears to be involved in the infectious process in addition to providing the bacteria with a means of escaping the host's immune systems. However, the genome of M. pneumoniae does not encode any of the known genes found in other bacterial motility systems or any conventional motor proteins that are responsible for eukaryotic motility. Thus, further analysis of the mechanism underlying M. pneumoniae gliding is warranted. The gliding machinery formed as the membrane protrusion can be divided into the surface and internal structures. On the surface, P1 adhesin, a 170 kDa transmembrane protein forms an adhesin complex with other two proteins. The internal structure features a terminal button, paired plates, and a bowl (wheel) complex. In total, the organelle is composed of more than 15 proteins. By integrating the currently available information by genetics, microscopy, and structural analyses, we have suggested a working model for the architecture of the organelle. Furthermore, in this article, we suggest and discuss a possible mechanism of gliding based on the structural model, in which the force generated around the bowl complex transmits through the paired plates, reaching the adhesin complex, resulting in the repeated catch of sialylated oligosaccharides on the host surface by the adhesin complex.
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Affiliation(s)
- Makoto Miyata
- Department of Biology, Graduate School of Science, Osaka City UniversityOsaka, Japan; The OCU Advanced Research Institute for Natural Science and Technology, Osaka City UniversityOsaka, Japan
| | - Tasuku Hamaguchi
- Department of Biology, Graduate School of Science, Osaka City UniversityOsaka, Japan; The OCU Advanced Research Institute for Natural Science and Technology, Osaka City UniversityOsaka, Japan
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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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Abstract
Cryo-electron tomography (cryo-ET) has emerged as a leading technique for three-dimensional visualization of large macromolecular complexes and their conformational changes in their native cellular environment. However, the resolution and potential applications of cryo-ET are fundamentally limited by specimen thickness, preventing high-resolution in situ visualization of macromolecular structures in many bacteria (such as Escherichia coli and Salmonella enterica). Minicells, which were discovered nearly 50 years ago, have recently been exploited as model systems to visualize molecular machines in situ, due to their smaller size and other unique properties. In this review, we discuss strategies for producing minicells and highlight their use in the study of chemotactic signaling, protein secretion, and DNA translocation. In combination with powerful genetic tools and advanced imaging techniques, minicells provide a springboard for in-depth structural studies of bacterial macromolecular complexes in situ and therefore offer a unique approach for gaining novel structural insights into many important processes in microbiology.
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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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42
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Zhang Y, Bao H, Miao F, Peng Y, Shen Y, Gu W, Meng Q, Wang W, Zhang J. Production and application of polyclonal and monoclonal antibodies against Spiroplasma eriocheiris. Sci Rep 2015; 5:17871. [PMID: 26639364 PMCID: PMC4671143 DOI: 10.1038/srep17871] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 11/06/2015] [Indexed: 11/09/2022] Open
Abstract
A new species of spiroplasma, Spiroplasma eriocheiris (S. eriocheiris), was identified as a lethal pathogen of tremor disease (TD) in Chinese mitten crab recently. In order to acquire appropriate biological and diagnostic tools for characterizing this newly discovered pathogen, 5 monoclonal antibodies (mAbs) and a polyclonal antibody (pAb) against S. eriocheiris were produced. Among the mAbs, 6F5, 7C8 and 12H5 lead to the deformation of S. eriocheiris. A peptide sequence, YMRDMQSGLPRY was identified as a mimic motif of MreB that is the cell shape determining protein of S. eriocheiris interacting with 3 mAbs. Furthermore, a double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) for detection of S. eriocheiris was established using the mAb and pAb we prepared. It detected as low as 0.1 μg/mL of S. eriocheiris. No cross-reaction was observed with three other common bacteria (Pseudomonas aeruginosa, Escherichia coli, and Bacillus subtilis) and the hemolymph samples of healthy Eriocheir sinensis. Collectively, our results indicated that the mAbs and pAb we prepared could be used in the analysis of S. eriocheiris membrane proteins mimotope and development of a diagnostic kit for S. eriocheiris infections.
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Affiliation(s)
- Ying Zhang
- Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Department of Microbiology and Immunology, Medical School, Southeast University, 87 Dingjiaqiao Road, Nanjing 210009, China
| | - Haixun Bao
- Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Department of Microbiology and Immunology, Medical School, Southeast University, 87 Dingjiaqiao Road, Nanjing 210009, China
| | - Fengqin Miao
- Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Department of Microbiology and Immunology, Medical School, Southeast University, 87 Dingjiaqiao Road, Nanjing 210009, China
| | - Yaqin Peng
- Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Department of Microbiology and Immunology, Medical School, Southeast University, 87 Dingjiaqiao Road, Nanjing 210009, China
| | - Yuqing Shen
- Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Department of Microbiology and Immunology, Medical School, Southeast University, 87 Dingjiaqiao Road, Nanjing 210009, China
| | - Wei Gu
- Jiangsu Key Laboratory for Biodiversity &Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China
| | - Qingguo Meng
- Jiangsu Key Laboratory for Biodiversity &Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China
| | - Wen Wang
- Jiangsu Key Laboratory for Biodiversity &Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China
| | - Jianqiong Zhang
- Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Department of Microbiology and Immunology, Medical School, Southeast University, 87 Dingjiaqiao Road, Nanjing 210009, China
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Song X, Tang Y, Lei C, Cao M, Shen Y, Yang Y. In situ visualizing T-Tubule/SR junction reveals the ultra-structures of calcium storage and release machinery. Int J Biol Macromol 2015; 82:7-12. [PMID: 26454109 DOI: 10.1016/j.ijbiomac.2015.10.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 10/01/2015] [Accepted: 10/05/2015] [Indexed: 10/22/2022]
Abstract
In skeletal muscle, Ca(2+) release from sarcoplasmic reticulum (SR) following the action potential relies on the delicate architecture of the T-Tubule/SR junction. The T-Tubule/SR junction comprises two membrane systems: the integral proteins DHPR and RyR1 and the Ca(2+)-buffering apparatus within the SR lumen. The arrangement and interactions of the components have remained elusive due to technological limitations. Here, we determined whether electron tomography is effective fort the in situ determination of the relationships between RyR1 and DHPR, the SR membrane and other involved structures. First, we visually confirmed that RyR1 and DHPR are close neighbors that are mutually staggered with each other and directly interact with one of RyR1 subunits. Second, the Ca(2+) storage network within the SR lumen is directly correlated with RyR1. These results suggest that the excitation of the T-Tubule may induce Ca(2+) release through a direct interaction among DHPR, RyR1 and the Ca(2+) buffering apparatus. These results indicate that electron tomography has potential as an efficient method for the in situ characterization of the complex architecture and arrangement of two integral-integral-membrane proteins in the context of the surrounding phospholipid-bilayer and proteins.
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Affiliation(s)
- XiaoWei Song
- Department of Biophysics, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China
| | - Ying Tang
- Department of Biophysics, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China
| | - ChangHai Lei
- Department of Biophysics, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China
| | - Mi Cao
- Department of Biophysics, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China
| | - YaFeng Shen
- Department of Biophysics, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China
| | - YongJi Yang
- Department of Biophysics, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China.
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Developments in cryo-electron tomography for in situ structural analysis. Arch Biochem Biophys 2015; 581:78-85. [DOI: 10.1016/j.abb.2015.04.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 04/14/2015] [Accepted: 04/19/2015] [Indexed: 12/31/2022]
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Genome sequence of the Drosophila melanogaster male-killing Spiroplasma strain MSRO endosymbiont. mBio 2015; 6:mBio.02437-14. [PMID: 25827421 PMCID: PMC4453565 DOI: 10.1128/mbio.02437-14] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Spiroplasmas are helical and motile members of a cell wall-less eubacterial group called Mollicutes. Although all spiroplasmas are associated with arthropods, they exhibit great diversity with respect to both their modes of transmission and their effects on their hosts; ranging from horizontally transmitted pathogens and commensals to endosymbionts that are transmitted transovarially (i.e., from mother to offspring). Here we provide the first genome sequence, along with proteomic validation, of an endosymbiotic inherited Spiroplasma bacterium, the Spiroplasma poulsonii MSRO strain harbored by Drosophila melanogaster. Comparison of the genome content of S. poulsonii with that of horizontally transmitted spiroplasmas indicates that S. poulsonii has lost many metabolic pathways and transporters, demonstrating a high level of interdependence with its insect host. Consistent with genome analysis, experimental studies showed that S. poulsonii metabolizes glucose but not trehalose. Notably, trehalose is more abundant than glucose in Drosophila hemolymph, and the inability to metabolize trehalose may prevent S. poulsonii from overproliferating. Our study identifies putative virulence genes, notably, those for a chitinase, the H2O2-producing glycerol-3-phosphate oxidase, and enzymes involved in the synthesis of the eukaryote-toxic lipid cardiolipin. S. poulsonii also expresses on the cell membrane one functional adhesion-related protein and two divergent spiralin proteins that have been implicated in insect cell invasion in other spiroplasmas. These lipoproteins may be involved in the colonization of the Drosophila germ line, ensuring S. poulsonii vertical transmission. The S. poulsonii genome is a valuable resource to explore the mechanisms of male killing and symbiont-mediated protection, two cardinal features of many facultative endosymbionts. Most insect species, including important disease vectors and crop pests, harbor vertically transmitted endosymbiotic bacteria. These endosymbionts play key roles in their hosts’ fitness, including protecting them against natural enemies and manipulating their reproduction in ways that increase the frequency of symbiont infection. Little is known about the molecular mechanisms that underlie these processes. Here, we provide the first genome draft of a vertically transmitted male-killing Spiroplasma bacterium, the S. poulsonii MSRO strain harbored by D. melanogaster. Analysis of the S. poulsonii genome was complemented by proteomics and ex vivo metabolic experiments. Our results indicate that S. poulsonii has reduced metabolic capabilities and expresses divergent membrane lipoproteins and potential virulence factors that likely participate in Spiroplasma-host interactions. This work fills a gap in our knowledge of insect endosymbionts and provides tools with which to decipher the interaction between Spiroplasma bacteria and their well-characterized host D. melanogaster, which is emerging as a model of endosymbiosis.
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Wu H, Iwai N, Nakano T, Ooi Y, Ishihara S, Sano K. Route of intrabacterial nanotransportation system for CagA in Helicobacter pylori. Med Mol Morphol 2015; 48:191-203. [PMID: 25707504 DOI: 10.1007/s00795-015-0097-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2014] [Accepted: 02/05/2015] [Indexed: 12/11/2022]
Abstract
Helicobacter pylori (H. pylori) possesses an intrabacterial nanotransportation system (ibNoTS) for transporting CagA and urease within the bacterial cytoplasm; this system is controlled by the extrabacterial environment. The transportation routes of the system have not yet been studied in detail. In this study, we demonstrated by immunoelectron microscopy that CagA localizes closely with the MreB filament in the bacterium, and MreB polymerization inhibitor A22 obstructs ibNoTS for CagA. These findings indicate that the route of ibNoTS for CagA is closely associated with the MreB filament. Because these phenomena were not observed in ibNoTS for urease, the route of ibNoTS for CagA is different from that of ibNoTS for urease as previously suggested. We propose that the route of ibNoTS for CagA is associated with the MreB filament in H. pylori.
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Affiliation(s)
- Hong Wu
- Project Team for Study of Nanotransportation System, Central Research Center, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka, 569-8686, Japan. .,Department of Microbiology and Infection Control, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka, 569-8686, Japan.
| | - Noritaka Iwai
- Project Team for Study of Nanotransportation System, Central Research Center, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka, 569-8686, Japan.,Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa, 226-8501, Japan
| | - Takashi Nakano
- Project Team for Study of Nanotransportation System, Central Research Center, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka, 569-8686, Japan.,Department of Microbiology and Infection Control, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka, 569-8686, Japan
| | - Yukimasa Ooi
- Department of Microbiology and Infection Control, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka, 569-8686, Japan.,Infection Control Office, Osaka Medical College Hospital, Osaka, Japan
| | - Sonoko Ishihara
- Department of Microbiology and Infection Control, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka, 569-8686, Japan
| | - Kouichi Sano
- Project Team for Study of Nanotransportation System, Central Research Center, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka, 569-8686, Japan.,Department of Microbiology and Infection Control, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka, 569-8686, Japan
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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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Fu X, Himes BA, Ke D, Rice WJ, Ning J, Zhang P. Controlled bacterial lysis for electron tomography of native cell membranes. Structure 2014; 22:1875-1882. [PMID: 25456413 DOI: 10.1016/j.str.2014.09.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 09/22/2014] [Accepted: 09/27/2014] [Indexed: 11/16/2022]
Abstract
Cryo-electron tomography (cryoET) has become a powerful tool for direct visualization of 3D structures of native biological specimens at molecular resolution, but its application is limited to thin specimens (<300 nm). Recently, vitreous sectioning and cryoFIB milling technologies were developed to physically reduce the specimen thickness; however, cryoET analysis of membrane protein complexes within native cell membranes remains a great challenge. Here, we use phage ΦX174 lysis gene E to rapidly produce native, intact, bacterial cell membranes for high resolution cryoET. We characterized E gene-induced cell lysis using FIB/SEM and cryoEM and showed that the bacteria cytoplasm was largely depleted through spot lesion, producing ghosts with the cell membranes intact. We further demonstrated the utility of E-gene-induced lysis for cryoET using the bacterial chemotaxis receptor signaling complex array. The described method should have a broad application for structural and functional studies of native, intact cell membranes and membrane protein complexes.
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Affiliation(s)
- Xiaofeng Fu
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Benjamin A Himes
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Danxia Ke
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - William J Rice
- New York Structural Biology Center, 89 Convent Avenue, New York, NY 10027, USA
| | - Jiying Ning
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Peijun Zhang
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Department of Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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Ku C, Lo WS, Kuo CH. Molecular evolution of the actin-like MreB protein gene family in wall-less bacteria. Biochem Biophys Res Commun 2014; 446:927-32. [DOI: 10.1016/j.bbrc.2014.03.039] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 03/10/2014] [Indexed: 01/01/2023]
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