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Hu Q, Zhang L, Yang R, Tang J, Dong G. Quaternary ammonium biocides promote conjugative transfer of antibiotic resistance gene in structure- and species-dependent manner. ENVIRONMENT INTERNATIONAL 2024; 189:108812. [PMID: 38878503 DOI: 10.1016/j.envint.2024.108812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 06/03/2024] [Accepted: 06/09/2024] [Indexed: 06/19/2024]
Abstract
The linkage between biocides and antibiotic resistance has been widely suggested in laboratories and various environments. However, the action mechanism of biocides on antibiotic resistance genes (ARGs) spread is still unclear. Thus, 6 quaternary ammonium biocides (QACs) with different bonded substituents or alkyl chain lengths were selected to assess their effects on the conjugation transfer of ARGs in this study. Two conjugation models with the same donor (E. coli DH5α (RP4)) into two receptors, E. coli MG1655 and pathogenic S. sonnei SE6-1, were constructed. All QACs were found to significantly promote intra- and inter-genus conjugative transfer of ARGs, and the frequency was highly impacted by their structure and receptors. At the same environmental exposure level (4 × 10-1 mg/L), didecyl dimethyl ammonium chloride (DDAC (C10)) promoted the most frequency of conjugative transfer, while benzathine chloride (BEC) promoted the least. With the same donor, the enhanced frequency of QACs of intra-transfer is higher than inter-transfer. Then, the acquisition mechanisms of two receptors were further determined using biochemical combined with transcriptome analysis. For the recipient E. coli, the promotion of the intragenus conjugative transfer may be associated with increased cell membrane permeability, reactive oxygen species (ROS) production and proton motive force (PMF)-induced enhancement of flagellar motility. Whereas, the increase of cell membrane permeability and decreased flagellar motility due to PMF disruption but encouraged biofilm formation, maybe the main reasons for promoting intergenus conjugative transfer in the recipient S. sonnei. As one pathogenic bacterium, S. sonnei was first found to acquire ARGs by biocide exposure.
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Affiliation(s)
- Qin Hu
- Key Laboratory of Three Gorges Reservoir Region's Eco-environment, Ministry of Education, Chongqing University, Chongqing 400045, China; State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China
| | - Lilan Zhang
- Key Laboratory of Three Gorges Reservoir Region's Eco-environment, Ministry of Education, Chongqing University, Chongqing 400045, China; State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China.
| | - Rui Yang
- Key Laboratory of Three Gorges Reservoir Region's Eco-environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Jialin Tang
- Key Laboratory of Three Gorges Reservoir Region's Eco-environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Guoliang Dong
- Key Laboratory of Three Gorges Reservoir Region's Eco-environment, Ministry of Education, Chongqing University, Chongqing 400045, China
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2
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Ciolli Mattioli C, Eisner K, Rosenbaum A, Wang M, Rivalta A, Amir A, Golding I, Avraham R. Physiological stress drives the emergence of a Salmonella subpopulation through ribosomal RNA regulation. Curr Biol 2023; 33:4880-4892.e14. [PMID: 37879333 PMCID: PMC10843543 DOI: 10.1016/j.cub.2023.09.064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 08/24/2023] [Accepted: 09/26/2023] [Indexed: 10/27/2023]
Abstract
Bacteria undergo cycles of growth and starvation to which they must adapt swiftly. One important strategy for adjusting growth rates relies on ribosomal levels. Although high ribosomal levels are required for fast growth, their dynamics during starvation remain unclear. Here, we analyzed ribosomal RNA (rRNA) content of individual Salmonella cells by using fluorescence in situ hybridization (rRNA-FISH) and measured a dramatic decrease in rRNA numbers only in a subpopulation during nutrient limitation, resulting in a bimodal distribution of cells with high and low rRNA content. During nutritional upshifts, the two subpopulations were associated with distinct phenotypes. Using a transposon screen coupled with rRNA-FISH, we identified two mutants, DksA and RNase I, acting on rRNA transcription shutdown and degradation, which abolished the formation of the subpopulation with low rRNA content. Our work identifies a bacterial mechanism for regulation of ribosomal bimodality that may be beneficial for population survival during starvation.
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Affiliation(s)
- Camilla Ciolli Mattioli
- Department of Immunology and Regenerative Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Kfir Eisner
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Aviel Rosenbaum
- Department of Immunology and Regenerative Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Mengyu Wang
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Andre' Rivalta
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ariel Amir
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ido Golding
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Roi Avraham
- Department of Immunology and Regenerative Biology, Weizmann Institute of Science, Rehovot 7610001, Israel.
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3
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Palma V, Gutiérrez MS, Vargas O, Parthasarathy R, Navarrete P. Methods to Evaluate Bacterial Motility and Its Role in Bacterial–Host Interactions. Microorganisms 2022; 10:microorganisms10030563. [PMID: 35336138 PMCID: PMC8953368 DOI: 10.3390/microorganisms10030563] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/02/2022] [Accepted: 02/06/2022] [Indexed: 11/16/2022] Open
Abstract
Bacterial motility is a widespread characteristic that can provide several advantages for the cell, allowing it to move towards more favorable conditions and enabling host-associated processes such as colonization. There are different bacterial motility types, and their expression is highly regulated by the environmental conditions. Because of this, methods for studying motility under realistic experimental conditions are required. A wide variety of approaches have been developed to study bacterial motility. Here, we present the most common techniques and recent advances and discuss their strengths as well as their limitations. We classify them as macroscopic or microscopic and highlight the advantages of three-dimensional imaging in microscopic approaches. Lastly, we discuss methods suited for studying motility in bacterial–host interactions, including the use of the zebrafish model.
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Affiliation(s)
- Victoria Palma
- Laboratory of Microbiology and Probiotics, Institute of Nutrition and Food Technology (INTA), University of Chile, El Líbano 5524, Santiago 7830490, Chile; (V.P.); (M.S.G.); (O.V.)
| | - María Soledad Gutiérrez
- Laboratory of Microbiology and Probiotics, Institute of Nutrition and Food Technology (INTA), University of Chile, El Líbano 5524, Santiago 7830490, Chile; (V.P.); (M.S.G.); (O.V.)
- Millennium Science Initiative Program, Milenium Nucleus in the Biology of the Intestinal Microbiota, National Agency for Research and Development (ANID), Moneda 1375, Santiago 8200000, Chile
| | - Orlando Vargas
- Laboratory of Microbiology and Probiotics, Institute of Nutrition and Food Technology (INTA), University of Chile, El Líbano 5524, Santiago 7830490, Chile; (V.P.); (M.S.G.); (O.V.)
| | - Raghuveer Parthasarathy
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA;
- Department of Physics and Materials Science Institute, University of Oregon, Eugene, OR 97403, USA
| | - Paola Navarrete
- Laboratory of Microbiology and Probiotics, Institute of Nutrition and Food Technology (INTA), University of Chile, El Líbano 5524, Santiago 7830490, Chile; (V.P.); (M.S.G.); (O.V.)
- Millennium Science Initiative Program, Milenium Nucleus in the Biology of the Intestinal Microbiota, National Agency for Research and Development (ANID), Moneda 1375, Santiago 8200000, Chile
- Correspondence:
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Rashid FZM, Mahlandt E, van der Vaart M, Boer DEC, Varela Alvarez M, Henneman B, Brocken DJW, Voskamp P, Blok A, Shimizu T, Meijer A, Luijsterburg M, Goedhart J, Crémazy FGE, Dame R. HI-NESS: a family of genetically encoded DNA labels based on a bacterial nucleoid-associated protein. Nucleic Acids Res 2021; 50:e10. [PMID: 34734265 PMCID: PMC8789088 DOI: 10.1093/nar/gkab993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 10/06/2021] [Accepted: 10/08/2021] [Indexed: 02/02/2023] Open
Abstract
The interplay between three-dimensional chromosome organisation and genomic processes such as replication and transcription necessitates in vivo studies of chromosome dynamics. Fluorescent organic dyes are often used for chromosome labelling in vivo. The mode of binding of these dyes to DNA cause its distortion, elongation, and partial unwinding. The structural changes induce DNA damage and interfere with the binding dynamics of chromatin-associated proteins, consequently perturbing gene expression, genome replication, and cell cycle progression. We have developed a minimally-perturbing, genetically encoded fluorescent DNA label consisting of a (photo-switchable) fluorescent protein fused to the DNA-binding domain of H-NS — a bacterial nucleoid-associated protein. We show that this DNA label, abbreviated as HI-NESS (H-NS-based indicator for nucleic acid stainings), is minimally-perturbing to genomic processes and labels chromosomes in eukaryotic cells in culture, and in zebrafish embryos with preferential binding to AT-rich chromatin.
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Affiliation(s)
- Fatema-Zahra M Rashid
- Macromolecular Biochemistry, Leiden Institute of Chemistry, Leiden University, Leiden 2333CC, The Netherlands
- Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands
| | - Eike Mahlandt
- Molecular Cytology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam 1098XH, The Netherlands
| | - Michiel van der Vaart
- Animal Sciences, Institute of Biology Leiden, Leiden University, Leiden 2333CC, The Netherlands
| | - Daphne E C Boer
- Department of Human Genetics, Leiden University Medical Center, Leiden 2333ZC, The Netherlands
| | - Monica Varela Alvarez
- Animal Sciences, Institute of Biology Leiden, Leiden University, Leiden 2333CC, The Netherlands
| | - Bram Henneman
- Macromolecular Biochemistry, Leiden Institute of Chemistry, Leiden University, Leiden 2333CC, The Netherlands
| | - Daan J W Brocken
- Macromolecular Biochemistry, Leiden Institute of Chemistry, Leiden University, Leiden 2333CC, The Netherlands
| | - Patrick Voskamp
- Biophysical Structural Chemistry, Leiden Institute of Chemistry, Leiden University, Leiden 2333CC, The Netherlands
| | - Anneloes J Blok
- Macromolecular Biochemistry, Leiden Institute of Chemistry, Leiden University, Leiden 2333CC, The Netherlands
| | - Thomas S Shimizu
- Systems Biology, AMOLF Institute, Amsterdam 1098XG, The Netherlands
| | - Annemarie H Meijer
- Animal Sciences, Institute of Biology Leiden, Leiden University, Leiden 2333CC, The Netherlands
| | - Martijn S Luijsterburg
- Department of Human Genetics, Leiden University Medical Center, Leiden 2333ZC, The Netherlands
| | - Joachim Goedhart
- Molecular Cytology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam 1098XH, The Netherlands
| | - Frédéric G E Crémazy
- Macromolecular Biochemistry, Leiden Institute of Chemistry, Leiden University, Leiden 2333CC, The Netherlands
| | - Remus T Dame
- To whom correspondence should be addressed. Tel: +31 71 527 5605;
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Localization of Native Mms13 to the Magnetosome Chain of Magnetospirillum magneticum AMB-1 Using Immunogold Electron Microscopy, Immunofluorescence Microscopy and Biochemical Analysis. CRYSTALS 2021. [DOI: 10.3390/cryst11080874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Magnetotactic bacteria (MTB) biomineralize intracellular magnetite (Fe3O4) crystals surrounded by a magnetosome membrane (MM). The MM contains membrane-specific proteins that control Fe3O4 mineralization in MTB. Previous studies have demonstrated that Mms13 is a critical protein within the MM. Mms13 can be isolated from the MM fraction of Magnetospirillum magneticum AMB-1 and a Mms13 homolog, MamC, has been shown to control the size and shape of magnetite nanocrystals synthesized in-vitro. The objective of this study was to use several independent methods to definitively determine the localization of native Mms13 in M. magneticum AMB-1. Using Mms13-immunogold labeling and transmission electron microscopy (TEM), we found that Mms13 is localized to the magnetosome chain of M. magneticum AMB-1 cells. Mms13 was detected in direct contact with magnetite crystals or within the MM. Immunofluorescence detection of Mms13 in M. magneticum AMB-1 cells by confocal laser scanning microscopy (CLSM) showed Mms13 localization along the length of the magnetosome chain. Proteins contained within the MM were resolved by SDS-PAGE for Western blot analysis and LC-MS/MS (liquid chromatography with tandem mass spectrometry) protein sequencing. Using Anti-Mms13 antibody, a protein band with a molecular mass of ~14 kDa was detected in the MM fraction only. This polypeptide was digested with trypsin, sequenced by LC-MS/MS and identified as magnetosome protein Mms13. Peptides corresponding to the protein’s putative MM domain and catalytic domain were both identified by LC-MS/MS. Our results (Immunogold TEM, Immunofluorescence CLSM, Western blot, LC-MS/MS), combined with results from previous studies, demonstrate that Mms13 and homolog proteins MamC and Mam12, are localized to the magnetosome chain in MTB belonging to the class Alphaproteobacteria. Because of their shared localization in the MM and highly conserved amino acid sequences, it is likely that MamC, Mam12, and Mms13 share similar roles in the biomineralization of Fe3O4 nanocrystals.
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Wolf P, Gavins G, Beck‐Sickinger AG, Seitz O. Strategies for Site-Specific Labeling of Receptor Proteins on the Surfaces of Living Cells by Using Genetically Encoded Peptide Tags. Chembiochem 2021; 22:1717-1732. [PMID: 33428317 PMCID: PMC8248378 DOI: 10.1002/cbic.202000797] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 01/08/2021] [Indexed: 12/14/2022]
Abstract
Fluorescence microscopy imaging enables receptor proteins to be investigated within their biological context. A key challenge is to site-specifically incorporate reporter moieties into proteins without interfering with biological functions or cellular networks. Small peptide tags offer the opportunity to combine inducible labeling with small tag sizes that avoid receptor perturbation. Herein, we review the current state of live-cell labeling of peptide-tagged cell-surface proteins. Considering their importance as targets in medicinal chemistry, we focus on membrane receptors such as G protein-coupled receptors (GPCRs) and receptor tyrosine kinases (RTKs). We discuss peptide tags that i) are subject to enzyme-mediated modification reactions, ii) guide the complementation of reporter proteins, iii) form coiled-coil complexes, and iv) interact with metal complexes. Given our own contributions in the field, we place emphasis on peptide-templated labeling chemistry.
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Affiliation(s)
- Philipp Wolf
- Faculty of Life SciencesInstitute of BiochemistryLeipzig UniversityBrüderstrasse 3404103LeipzigGermany
| | - Georgina Gavins
- Faculty of Mathematics and Natural SciencesDepartment of ChemistryHumboldt-Universität zu BerlinBrook-Taylor-Str. 212489BerlinGermany
| | - Annette G. Beck‐Sickinger
- Faculty of Life SciencesInstitute of BiochemistryLeipzig UniversityBrüderstrasse 3404103LeipzigGermany
| | - Oliver Seitz
- Faculty of Mathematics and Natural SciencesDepartment of ChemistryHumboldt-Universität zu BerlinBrook-Taylor-Str. 212489BerlinGermany
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7
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Gurung JP, Navvab Kashani M, Agarwal S, Peralta G, Gel M, Baker MAB. Separation and enrichment of sodium-motile bacteria using cost-effective microfluidics. BIOMICROFLUIDICS 2021; 15:034108. [PMID: 34084258 PMCID: PMC8163512 DOI: 10.1063/5.0046941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 05/10/2021] [Indexed: 06/12/2023]
Abstract
Many motile bacteria are propelled by the rotation of flagellar filaments. This rotation is driven by a membrane protein known as the stator-complex, which drives the rotor of the bacterial flagellar motor. Torque generation is powered in most cases by proton transit through membrane protein complexes known as stators, with the next most common ionic power source being sodium. Sodium-powered stators can be studied through the use of synthetic chimeric stators that combine parts of sodium- and proton-powered stator proteins. The most well studied example is the use of the sodium-powered PomA-PotB chimeric stator unit in the naturally proton-powered Escherichia coli. Here we designed a fluidics system at low cost for rapid prototyping to separate motile and non-motile populations of bacteria while varying the ionic composition of the media and thus the sodium-motive force available to drive this chimeric flagellar motor. We measured separation efficiencies at varying ionic concentrations and confirmed using fluorescence that our device delivered eightfold enrichment of the motile proportion of a mixed population. Furthermore, our results showed that we could select bacteria from reservoirs where sodium was not initially present. Overall, this technique can be used to implement the selection of highly motile fractions from mixed liquid cultures, with applications in directed evolution to investigate the adaptation of motility in bacterial ecosystems.
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Affiliation(s)
- Jyoti P. Gurung
- School of Biotechnology and Biomolecular Science, UNSW Sydney, Sydney, NSW 2052, Australia
| | | | - Sanaz Agarwal
- School of Biotechnology and Biomolecular Science, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Gonzalo Peralta
- School of Biotechnology and Biomolecular Science, UNSW Sydney, Sydney, NSW 2052, Australia
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8
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Brown NW, Shirley JD, Marshall AP, Carlson EE. Comparison of Bioorthogonal β-Lactone Activity-Based Probes for Selective Labeling of Penicillin-Binding Proteins. Chembiochem 2021; 22:193-202. [PMID: 32964667 PMCID: PMC7790944 DOI: 10.1002/cbic.202000556] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/21/2020] [Indexed: 01/20/2023]
Abstract
Penicillin-binding proteins (PBPs) are a family of bacterial enzymes that are key components of cell-wall biosynthesis and the target of β-lactam antibiotics. Most microbial pathogens contain multiple structurally homologous PBP isoforms, making it difficult to target individual PBPs. To study the roles and regulation of specific PBP isoforms, a panel of bioorthogonal β-lactone probes was synthesized and compared. Fluorescent labeling confirmed selectivity, and PBPs were selectively enriched from Streptococcus pneumoniae lysates. Comparisons between fluorescent labeling of probes revealed that the accessibility of bioorthogonal reporter molecules to the bound probe in the native protein environment exerts a more significant effect on labeling intensity than the bioorthogonal reaction used, observations that are likely applicable beyond this class of probes or proteins. Selective, bioorthogonal activity-based probes for PBPs will facilitate the activity-based determination of the roles and regulation of specific PBP isoforms, a key gap in knowledge that has yet to be filled.
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Affiliation(s)
- Nathaniel W Brown
- Department of Chemistry, University of Minnesota-Twin Cities 139 Smith Hall, Pleasant Street SE, Minneapolis, MN, 55455, USA
| | - Joshua D Shirley
- Department of Medicinal Chemistry, University of Minnesota-Twin Cities, 308 Harvard Street SE, Minneapolis, MN, 55455, USA
| | - Andrew P Marshall
- Department of Chemistry, University of Minnesota-Twin Cities 139 Smith Hall, Pleasant Street SE, Minneapolis, MN, 55455, USA
| | - Erin E Carlson
- Department of Chemistry, University of Minnesota-Twin Cities 139 Smith Hall, Pleasant Street SE, Minneapolis, MN, 55455, USA
- Department of Medicinal Chemistry, University of Minnesota-Twin Cities, 308 Harvard Street SE, Minneapolis, MN, 55455, USA
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota-Twin Cities, 321 Church Street SE, Minneapolis, MN, 55455, USA
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9
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Montecinos-Franjola F, Bauer BL, Mears JA, Ramachandran R. GFP fluorescence tagging alters dynamin-related protein 1 oligomerization dynamics and creates disassembly-refractory puncta to mediate mitochondrial fission. Sci Rep 2020; 10:14777. [PMID: 32901052 PMCID: PMC7479153 DOI: 10.1038/s41598-020-71655-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 08/19/2020] [Indexed: 01/22/2023] Open
Abstract
Green fluorescent protein (GFP)-tagging is the prevalent strategy to monitor protein dynamics in living cells. However, the consequences of appending the bulky GFP moiety to the protein of interest are rarely investigated. Here, using a powerful combination of quantitative fluorescence spectroscopic and imaging techniques, we have examined the oligomerization dynamics of the GFP-tagged mitochondrial fission GTPase dynamin-related protein 1 (Drp1) both in vitro and in vivo. We find that GFP-tagged Drp1 exhibits impaired oligomerization equilibria in solution that corresponds to a greatly diminished cooperative GTPase activity in comparison to native Drp1. Consequently, GFP-tagged Drp1 constitutes aberrantly stable, GTP-resistant supramolecular assemblies both in vitro and in vivo, neither of which reflects a more dynamic native Drp1 oligomerization state. Indeed, GFP-tagged Drp1 is detected more frequently per unit length over mitochondria in Drp1-null mouse embryonic fibroblasts (MEFs) compared to wild-type (wt) MEFs, indicating that the drastically reduced GTP turnover restricts oligomer disassembly from the mitochondrial surface relative to mixed oligomers comprising native and GFP-tagged Drp1. Yet, GFP-tagged Drp1 retains the capacity to mediate membrane constriction in vitro and mitochondrial division in vivo. These findings suggest that instead of robust assembly-disassembly dynamics, persistent Drp1 higher-order oligomerization over membranes is sufficient for mitochondrial fission.
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Affiliation(s)
- Felipe Montecinos-Franjola
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Brianna L Bauer
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Jason A Mears
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Rajesh Ramachandran
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA. .,Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
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10
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Morimoto YV, Namba K, Minamino T. GFP Fusion to the N-Terminus of MotB Affects the Proton Channel Activity of the Bacterial Flagellar Motor in Salmonella. Biomolecules 2020; 10:E1255. [PMID: 32872412 PMCID: PMC7564593 DOI: 10.3390/biom10091255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/25/2020] [Accepted: 08/27/2020] [Indexed: 12/28/2022] Open
Abstract
The bacterial flagellar motor converts the energy of proton flow through the MotA/MotB complex into mechanical works required for motor rotation. The rotational force is generated by electrostatic interactions between the stator protein MotA and the rotor protein FliG. The Arg-90 and Glu-98 from MotA interact with Asp-289 and Arg-281 of FliG, respectively. An increase in the expression level of the wild-type MotA/MotB complex inhibits motility of the gfp-motBfliG(R281V) mutant but not the fliG(R281V) mutant, suggesting that the MotA/GFP-MotB complex cannot work together with wild-type MotA/MotB in the presence of the fliG(R281V) mutation. However, it remains unknown why. Here, we investigated the effect of the GFP fusion to MotB at its N-terminus on the MotA/MotB function. Over-expression of wild-type MotA/MotB significantly reduced the growth rate of the gfp-motBfliG(R281V) mutant. The over-expression of the MotA/GFP-MotB complex caused an excessive proton leakage through its proton channel, thereby inhibiting cell growth. These results suggest that the GFP tag on the MotB N-terminus affects well-regulated proton translocation through the MotA/MotB proton channel. Therefore, we propose that the N-terminal cytoplasmic tail of MotB couples the gating of the proton channel with the MotA-FliG interaction responsible for torque generation.
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Affiliation(s)
- Yusuke V. Morimoto
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka 820-8502, Japan
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan; (K.N.); (T.M.)
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan; (K.N.); (T.M.)
- RIKEN Spring-8 Center & Center for Biosystems Dynamics Research (BDR), 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
- JEOL YOKOGUSHI Research Alliance Laboratories, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan; (K.N.); (T.M.)
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11
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Hill BD, Prabhu P, Rizvi SM, Wen F. Yeast Intracellular Staining (yICS): Enabling High-Throughput, Quantitative Detection of Intracellular Proteins via Flow Cytometry for Pathway Engineering. ACS Synth Biol 2020; 9:2119-2131. [PMID: 32603587 DOI: 10.1021/acssynbio.0c00199] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The complexities of pathway engineering necessitate screening libraries to discover phenotypes of interest. However, this approach is challenging when desirable phenotypes cannot be directly linked to growth advantages or fluorescence. In these cases, the ability to rapidly quantify intracellular proteins in the pathway of interest is critical to expedite the clonal selection process. While Saccharomyces cerevisiae remains a common host for pathway engineering, current approaches for intracellular protein detection in yeast either have low throughput, can interfere with protein function, or lack the ability to detect multiple proteins simultaneously. To fill this need, we developed yeast intracellular staining (yICS) that enables fluorescent antibodies to access intracellular compartments of yeast cells while maintaining their cellular integrity for analysis by flow cytometry. Using the housekeeping proteins β actin and glyceraldehyde 3-phophate dehydrogenase (GAPDH) as targets for yICS, we demonstrated for the first time successful antibody-based flow cytometric detection of yeast intracellular proteins with no modification. Further, yICS characterization of a recombinant d-xylose assimilation pathway showed 3-plexed, quantitative detection of the xylose reductase (XR), xylitol dehydrogenase (XDH), and xylulokinase (XK) enzymes each fused with a small (6-10 amino acids) tag, revealing distinct enzyme expression profiles between plasmid-based and genome-integrated expression approaches. As a result of its high-throughput and quantitative capability, yICS enabled rapid screening of a library created from CRISPR-mediated XDH integration into the yeast δ site, identifying rare (1%) clones that led to an 8.4-fold increase in XDH activity. These results demonstrate the utility of yICS for greatly accelerating pathway engineering efforts, as well as any application where the high-throughput and quantitative detection of intracellular proteins is desired.
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Affiliation(s)
- Brett D. Hill
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Ponnandy Prabhu
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Syed M. Rizvi
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Fei Wen
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
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12
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Marshall AP, Shirley JD, Carlson EE. Enzyme-targeted fluorescent small-molecule probes for bacterial imaging. Curr Opin Chem Biol 2020; 57:155-165. [PMID: 32799037 DOI: 10.1016/j.cbpa.2020.05.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 05/27/2020] [Accepted: 05/29/2020] [Indexed: 12/26/2022]
Abstract
Molecular imaging methods to visualize myriad biochemical processes in bacteria have traditionally been dependent upon molecular biology techniques to incorporate fluorescent biomolecules (e.g., fusion proteins). Such methods have been instrumental in our understanding of how bacteria function but are not without drawbacks, including potential perturbation to native protein expression and function. To overcome these limitations, the use of fluorescent small-molecule probes has gained much attention. Here, we highlight examples from the recent literature that showcase the utility of small-molecule probes for the fluorescence imaging of bacterial cells, including electrophilic, metabolic, and enzyme-activated probes. Although the use of these types of compounds for bacterial imaging is still relatively new, the selected examples demonstrate the exciting potential of these critical tools in the exploration of bacterial physiology.
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Affiliation(s)
- Andrew P Marshall
- Department of Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Joshua D Shirley
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Erin E Carlson
- Department of Chemistry, University of Minnesota, Minneapolis, MN, United States; Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, United States; Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, United States.
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13
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Gurung JP, Gel M, Baker MAB. Microfluidic techniques for separation of bacterial cells via taxis. MICROBIAL CELL (GRAZ, AUSTRIA) 2020; 7:66-79. [PMID: 32161767 PMCID: PMC7052948 DOI: 10.15698/mic2020.03.710] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/24/2019] [Accepted: 01/10/2020] [Indexed: 12/22/2022]
Abstract
The microbial environment is typically within a fluid and the key processes happen at the microscopic scale where viscosity dominates over inertial forces. Microfluidic tools are thus well suited to study microbial motility because they offer precise control of spatial structures and are ideal for the generation of laminar fluid flows with low Reynolds numbers at microbial lengthscales. These tools have been used in combination with microscopy platforms to visualise and study various microbial taxes. These include establishing concentration and temperature gradients to influence motility via chemotaxis and thermotaxis, or controlling the surrounding microenvironment to influence rheotaxis, magnetotaxis, and phototaxis. Improvements in microfluidic technology have allowed fine separation of cells based on subtle differences in motility traits and have applications in synthetic biology, directed evolution, and applied medical microbiology.
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Affiliation(s)
- Jyoti P. Gurung
- School of Biotechnology and Biomolecular Science, UNSW Sydney
| | - Murat Gel
- CSIRO Manufacturing, Clayton
- CSIRO Future Science Platform for Synthetic Biology
| | - Matthew A. B. Baker
- School of Biotechnology and Biomolecular Science, UNSW Sydney
- CSIRO Future Science Platform for Synthetic Biology
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14
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Nord AL, Pedaci F. Mechanisms and Dynamics of the Bacterial Flagellar Motor. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1267:81-100. [PMID: 32894478 DOI: 10.1007/978-3-030-46886-6_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Many bacteria are able to actively propel themselves through their complex environment, in search of resources and suitable niches. The source of this propulsion is the Bacterial Flagellar Motor (BFM), a molecular complex embedded in the bacterial membrane which rotates a flagellum. In this chapter we review the known physical mechanisms at work in the motor. The BFM shows a highly dynamic behavior in its power output, its structure, and in the stoichiometry of its components. Changes in speed, rotation direction, constituent protein conformations, and the number of constituent subunits are dynamically controlled in accordance to external chemical and mechanical cues. The mechano-sensitivity of the motor is likely related to the surface-sensing ability of bacteria, relevant in the initial stage of biofilm formation.
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Affiliation(s)
- A L Nord
- Centre de Biochimie Structurale (CBS), INSERM, CNRS, University of Montpellier, Montpellier, France
| | - F Pedaci
- Centre de Biochimie Structurale (CBS), INSERM, CNRS, University of Montpellier, Montpellier, France.
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15
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Ferretti MB, Karbstein K. Does functional specialization of ribosomes really exist? RNA (NEW YORK, N.Y.) 2019; 25:521-538. [PMID: 30733326 PMCID: PMC6467006 DOI: 10.1261/rna.069823.118] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
It has recently become clear that ribosomes are much more heterogeneous than previously thought, with diversity arising from rRNA sequence and modifications, ribosomal protein (RP) content and posttranslational modifications (PTMs), as well as bound nonribosomal proteins. In some cases, the existence of these diverse ribosome populations has been verified by biochemical or structural methods. Furthermore, knockout or knockdown of RPs can diversify ribosome populations, while also affecting the translation of some mRNAs (but not others) with biological consequences. However, the effects on translation arising from depletion of diverse proteins can be highly similar, suggesting that there may be a more general defect in ribosome function or stability, perhaps arising from reduced ribosome numbers. Consistently, overall reduced ribosome numbers can differentially affect subclasses of mRNAs, necessitating controls for specificity. Moreover, in order to study the functional consequences of ribosome diversity, perturbations including affinity tags and knockouts are introduced, which can also affect the outcome of the experiment. Here we review the available literature to carefully evaluate whether the published data support functional diversification, defined as diverse ribosome populations differentially affecting translation of distinct mRNA (classes). Based on these observations and the commonly observed cellular responses to perturbations in the system, we suggest a set of important controls to validate functional diversity, which should include gain-of-function assays and the demonstration of inducibility under physiological conditions.
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Affiliation(s)
- Max B Ferretti
- Department of Integrative Structural and Molecular Biology, The Scripps Research Institute, Jupiter, Florida 33458, USA
- The Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, Jupiter, Florida 33458, USA
| | - Katrin Karbstein
- Department of Integrative Structural and Molecular Biology, The Scripps Research Institute, Jupiter, Florida 33458, USA
- The Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, Jupiter, Florida 33458, USA
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Abstract
The bacterial flagellar motor (BFM) is the rotary motor powering swimming of many motile bacteria. Many of the components of this molecular machine are dynamic, a property which allows the cell to optimize its behavior in accordance with the surrounding environment. A prime example is the stator unit, a membrane-bound ion channel that is responsible for applying torque to the rotor. The stator units are mechanosensitive, with the number of engaged units dependent on the viscous load on the motor. We measure the kinetics of the stators as a function of the viscous load and find that the mechanosensitivity of the BFM is governed by a catch bond: a counterintuitive type of bond that becomes stronger under force. The bacterial flagellar motor (BFM) is the rotary motor that rotates each bacterial flagellum, powering the swimming and swarming of many motile bacteria. The torque is provided by stator units, ion motive force-powered ion channels known to assemble and disassemble dynamically in the BFM. This turnover is mechanosensitive, with the number of engaged units dependent on the viscous load experienced by the motor through the flagellum. However, the molecular mechanism driving BFM mechanosensitivity is unknown. Here, we directly measure the kinetics of arrival and departure of the stator units in individual motors via analysis of high-resolution recordings of motor speed, while dynamically varying the load on the motor via external magnetic torque. The kinetic rates obtained, robust with respect to the details of the applied adsorption model, indicate that the lifetime of an assembled stator unit increases when a higher force is applied to its anchoring point in the cell wall. This provides strong evidence that a catch bond (a bond strengthened instead of weakened by force) drives mechanosensitivity of the flagellar motor complex. These results add the BFM to a short, but growing, list of systems demonstrating catch bonds, suggesting that this “molecular strategy” is a widespread mechanism to sense and respond to mechanical stress. We propose that force-enhanced stator adhesion allows the cell to adapt to a heterogeneous environmental viscosity and may ultimately play a role in surface-sensing during swarming and biofilm formation.
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