1
|
Iyer A, Frallicciardi J, le Paige UBA, Narasimhan S, Luo Y, Alvarez Sieiro P, Syga L, van den Brekel F, Minh Tran B, Tjioe R, Schuurman-Wolters G, C A Stuart M, Baldus M, van Ingen H, Poolman B. The structure and function of the bacterial osmotically inducible protein Y. J Mol Biol 2024:168668. [PMID: 38908784 DOI: 10.1016/j.jmb.2024.168668] [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: 04/18/2024] [Revised: 06/14/2024] [Accepted: 06/14/2024] [Indexed: 06/24/2024]
Abstract
The ability to adapt to osmotically diverse and fluctuating environments is critical to the survival and resilience of bacteria that colonize the human gut and urinary tract. Environmental stress often provides cross-protection against other challenges and increases antibiotic tolerance of bacteria. Thus, it is critical to understand how E. coli and other microbes survive and adapt to stress conditions. The osmotically inducible protein Y (OsmY) is significantly upregulated in response to hypertonicity. Yet its function remains unknown for decades. We determined the solution structure and dynamics of OsmY by nuclear magnetic resonance spectroscopy, which revealed that the two Bacterial OsmY and Nodulation (BON) domains of the protein are flexibly linked under low- and high-salinity conditions. In-cell solid-state NMR further indicates that there are no gross structural changes in OsmY as a function of osmotic stress. Using cryo-electron and super-resolution fluorescence microscopy, we show that OsmY attenuates plasmolysis-induced structural changes in E. coli and improves the time to growth resumption after osmotic upshift. Structure-guided mutational and functional studies demonstrate that exposed hydrophobic residues in the BON1 domain are critical for the function of OsmY. We find no evidence for membrane interaction of the BON domains of OsmY, contrary to current assumptions. Instead, at high ionic strength, we observe an interaction with the water channel, AqpZ. Thus, OsmY does not play a simple structural role in E. coli but may influence a cascade of osmoregulatory functions of the cell.
Collapse
Affiliation(s)
- Aditya Iyer
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
| | - Jacopo Frallicciardi
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Ulric B A le Paige
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Siddarth Narasimhan
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Yanzhang Luo
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Patricia Alvarez Sieiro
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Lukasz Syga
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Floris van den Brekel
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Buu Minh Tran
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Rendy Tjioe
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Gea Schuurman-Wolters
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Marc C A Stuart
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Marc Baldus
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Hugo van Ingen
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
| | - Bert Poolman
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
| |
Collapse
|
2
|
Kumar D, Gayen A, Chandra M. Membrane Permeability Dominates over Electrostatic Interactions in Dictating Drug Transport in Osmotically Shocked Escherichia coli. J Phys Chem B 2024; 128:4911-4921. [PMID: 38736363 DOI: 10.1021/acs.jpcb.3c08426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
To combat surging multidrug-resistant Gram-negative bacterial infections, better strategies to improve the efficacy of existing drugs are critical. Because the dual membrane cell envelope is the first line of defense for these bacteria, it is crucial to understand the permeation properties of the drugs through it. Our recent study shows that isosmotic conditions prevent drug permeation inside Gram-negative bacteria, Escherichia coli, while hypoosmotic stress enhances the process. Here, we unravel the reason behind such differential drug penetration. Specifically, we dissect the roles of electrostatic screening and low membrane permeability in the penetration failure of drugs under osmotically balanced conditions. We compare the transport of a quaternary ammonium compound malachite green in the presence of an electrolyte (NaCl) and a wide variety of commonly used organic osmolytes, e.g., sucrose, proline, glycerol, sorbitol, and urea. These osmolytes of different membrane permeability (i.e., nonpermeable sucrose and NaCl, freely permeable urea and glycerol, and partially permeable proline and sorbitol) clarify the role of osmotic stress in cell envelope permeability. The results showcase that under balanced osmotic conditions, drug molecules fail to penetrate inside E. coli cells because of low membrane permeabilities and not because of electrostatic screening imposed by the osmolytes. Contribution of the electrostatic interactions, however, cannot be completely overruled as at osmotically imbalanced conditions, drug transport across the bacterial subcellular compartments is found to be dependent on the osmolytes used.
Collapse
Affiliation(s)
- Deepak Kumar
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| | - Anindita Gayen
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| | - Manabendra Chandra
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
- Center of Excellence: Tropical and Infectious Diseases, Gangwal School of Medical Sciences and Technology, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| |
Collapse
|
3
|
Anand A, Kaňková H, Hájovská Z, Galusek D, Boccaccini AR, Galusková D. Bio-response of copper-magnesium co-substituted mesoporous bioactive glass for bone tissue regeneration. J Mater Chem B 2024; 12:1875-1891. [PMID: 38293829 DOI: 10.1039/d3tb01568h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Mesoporous bioactive glass (MBG) is widely acknowledged in bone tissue engineering due to its mesoporous structure, large surface area, and bioactivity. Recent research indicates that introduction of metallic ions has beneficial impacts on bone metabolism and angiogenesis. Thus, the features of MBG can be modified by incorporating combinations of ions, such as magnesium (Mg) and copper (Cu), which can play a considerable role in bone formation, influencing angiogenesis, osteogenesis, as well as antibacterial properties. In this study, Mg and Cu were co-doped for the first time (in a ratio of 1 : 1) in 80SiO2-5P2O5-(15 - 2x)CaO-xMgO-xCuO glass composition with x = 0, 0.5, 1, and 2 mol%, synthesized using the sol-gel and evaporation-induced self-assembly method. X-ray diffraction analysis confirmed the amorphous nature of the powders, while inductively coupled plasma-optical emission spectrometry verified the existence of dopant ions in the respective amounts. The nitrogen sorption method indicated the formation of uniform cylindrical mesopores which are open at both ends and a high surface area of the powders. TEM images show fringes, indicating an ordered mesoporous structure in all MgCu co-doped systems. In vitro bioactivity was observed in all MBG powders, confirmed by the formation of an apatite phase when placed in simulated body fluid (SBF). Flake-like microstructure characteristics of HAp crystals found on the surface of MBG powders were visualized using FESEM. Cytotoxicity tests at lower concentrations (0.1 and 1 wt/vol%) of co-doped 2MC MBG (co-doping up to 2 mol%) showed cell proliferation and viability of osteoblast-like MG-63 cells and normal human dermal fibroblast (NHDF) cells similar to the basic glass 80S. Antibacterial study of MBG pellets showed an increment in the zone of inhibition with the sequential addition of doping ions. The turbidity measurement of bacterial cultures revealed that the optimal concentration for effectively inhibiting bacterial growth was 1 wt/vol% (i.e., 10 mg mL-1) concentration of MBG extracts. The result suggested that the incorporation of Mg and Cu ions in MBG in lower concentrations of up to 2 mol% can be useful in bone regeneration owing to bioactivity, cell proliferation, and antibacterial characteristics.
Collapse
Affiliation(s)
- Akrity Anand
- Centre for Functional and Surface Functionalized Glass, TnUAD, 911 01 Trenčín, Slovakia.
- Institute of Biomaterials, University of Erlangen-Nuremberg, 91058 Erlangen, Germany.
| | - Hana Kaňková
- Centre for Functional and Surface Functionalized Glass, TnUAD, 911 01 Trenčín, Slovakia.
| | - Zuzana Hájovská
- Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, 845 13 Bratislava, Slovakia
| | - Dušan Galusek
- Centre for Functional and Surface Functionalized Glass, TnUAD, 911 01 Trenčín, Slovakia.
| | - Aldo R Boccaccini
- Institute of Biomaterials, University of Erlangen-Nuremberg, 91058 Erlangen, Germany.
| | - Dagmar Galusková
- Centre for Functional and Surface Functionalized Glass, TnUAD, 911 01 Trenčín, Slovakia.
| |
Collapse
|
4
|
Brauer AM, Shi H, Levin PA, Huang KC. Physiological and regulatory convergence between osmotic and nutrient stress responses in microbes. Curr Opin Cell Biol 2023; 81:102170. [PMID: 37119759 PMCID: PMC10493190 DOI: 10.1016/j.ceb.2023.102170] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 03/09/2023] [Accepted: 03/20/2023] [Indexed: 05/01/2023]
Abstract
Bacterial cells are regularly confronted with simultaneous changes in environmental nutrient supply and osmolarity. Despite the importance of osmolarity and osmoregulation in bacterial physiology, the relationship between the cellular response to osmotic perturbations and other stresses has remained largely unexplored. Bacteria cultured in hyperosmotic conditions and bacteria experiencing nutrient stress exhibit similar physiological changes, including metabolic shutdown, increased protein instability, dehydration, and condensation of chromosomal DNA. In this review, we highlight overlapping molecular players between osmotic and nutrient stresses. These connections between two seemingly disparate stress response pathways reinforce the importance of central carbon metabolism as a control point for diverse aspects of homeostatic regulation. We identify important open questions for future research, emphasizing the pressing need to develop and exploit new methods for probing how osmolarity affects phylogenetically diverse species.
Collapse
Affiliation(s)
- Adrienne M Brauer
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Handuo Shi
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Petra Anne Levin
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA.
| | - Kerwyn Casey Huang
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
| |
Collapse
|
5
|
L Pastrana C, Qiu L, Armon S, Gerland U, Amir A. Pressure-induced shape-shifting of helical bacteria. SOFT MATTER 2023; 19:2224-2230. [PMID: 36884021 DOI: 10.1039/d2sm01044e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Many bacterial species are helical in shape, including the widespread pathogen H. pylori. Motivated by recent experiments on H. pylori showing that cell wall synthesis is not uniform [J. A. Taylor, et al., eLife, 2020, 9, e52482], we investigate the possible formation of helical cell shape induced by elastic heterogeneity. We show, experimentally and theoretically, that helical morphogenesis can be produced by pressurizing an elastic cylindrical vessel with helical reinforced lines. The properties of the pressurized helix are highly dependent on the initial helical angle of the reinforced region. We find that steep angles result in crooked helices with, surprisingly, a reduced end-to-end distance upon pressurization. This work helps explain the possible mechanisms for the generation of helical cell morphologies and may inspire the design of novel pressure-controlled helical actuators.
Collapse
Affiliation(s)
- César L Pastrana
- Physics of Complex Biosystems, Technical University of Munich, 85748 Garching, Germany.
| | - Luyi Qiu
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.
| | - Shahaf Armon
- Department of Physics of Complex Systems, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Ulrich Gerland
- Physics of Complex Biosystems, Technical University of Munich, 85748 Garching, Germany.
| | - Ariel Amir
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.
- Department of Physics of Complex Systems, Weizmann Institute of Science, 7610001 Rehovot, Israel
| |
Collapse
|
6
|
Abu Quba AA, Goebel MO, Karagulyan M, Miltner A, Kästner M, Bachmann J, Schaumann GE, Diehl D. Changes in cell surface properties of Pseudomonas fluorescens by adaptation to NaCl induced hypertonic stress. FEMS MICROBES 2022; 4:xtac028. [PMID: 37333443 PMCID: PMC10169395 DOI: 10.1093/femsmc/xtac028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 10/26/2022] [Accepted: 12/05/2022] [Indexed: 10/12/2023] Open
Abstract
Determination of the effect of water stress on the surface properties of bacteria is crucial to study bacterial induced soil water repellency. Changes in the environmental conditions may affect several properties of bacteria such as the cell hydrophobicity and morphology. Here, we study the influence of adaptation to hypertonic stress on cell wettability, shape, adhesion, and surface chemical composition of Pseudomonas fluorescens. From this we aim to discover possible relations between the changes in wettability of bacterial films studied by contact angle and single cells studied by atomic and chemical force microscopy (AFM, CFM), which is still lacking. We show that by stress the adhesion forces of the cell surfaces towards hydrophobic functionalized probes increase while they decrease towards hydrophilic functionalized tips. This is consistent with the contact angle results. Further, cell size shrunk and protein content increased upon stress. The results suggest two possible mechanisms: Cell shrinkage is accompanied by the release of outer membrane vesicles by which the protein to lipid ratio increases. The higher protein content increases the rigidity and the number of hydrophobic nano-domains per surface area.
Collapse
Affiliation(s)
- Abd Alaziz Abu Quba
- Institute of Environmental Sciences, Rheinland-pfälzische Technische Universität Kaiserslauter-Landau, RPTU in Landau, Fortstrasse 7, 76829 Landau, Germany
| | - Marc-Oliver Goebel
- Institute of Soil Science, Leibniz Universität Hannover, Herrenhäuser Straße 2, 30419 Hannover, Germany
| | - Mariam Karagulyan
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig, Germany
| | - Anja Miltner
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig, Germany
| | - Matthias Kästner
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig, Germany
| | - Jörg Bachmann
- Institute of Soil Science, Leibniz Universität Hannover, Herrenhäuser Straße 2, 30419 Hannover, Germany
| | - Gabriele E Schaumann
- Institute of Environmental Sciences, Rheinland-pfälzische Technische Universität Kaiserslauter-Landau, RPTU in Landau, Fortstrasse 7, 76829 Landau, Germany
| | - Doerte Diehl
- Institute of Environmental Sciences, Rheinland-pfälzische Technische Universität Kaiserslauter-Landau, RPTU in Landau, Fortstrasse 7, 76829 Landau, Germany
| |
Collapse
|
7
|
Mena-Bueno S, Poveda-Urkixo I, Irazoki O, Palacios L, Cava F, Zabalza-Baranguá A, Grilló MJ. Brucella melitensis Wzm/Wzt System: Changes in the Bacterial Envelope Lead to Improved Rev1Δwzm Vaccine Properties. Front Microbiol 2022; 13:908495. [PMID: 35875565 PMCID: PMC9306315 DOI: 10.3389/fmicb.2022.908495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 05/26/2022] [Indexed: 11/13/2022] Open
Abstract
The lipopolysaccharide (LPS) O-polysaccharide (O-PS) is the main virulence factor in Brucella. After synthesis in the cytoplasmic membrane, O-PS is exported to the periplasm by the Wzm/Wzt system, where it is assembled into a LPS. This translocation also engages a bactoprenol carrier required for further biosynthesis pathways, such as cell wall biogenesis. Targeting O-PS export by blockage holds great potential for vaccine development, but little is known about the biological implications of each Wzm/Wzt moiety. To improve this knowledge and to elucidate its potential application as a vaccine, we constructed and studied wzm/wzt single- and double-deletion mutants, using the attenuated strain Brucella melitensis Rev1 as the parental strain. This allowed us to describe the composition of Brucella peptidoglycan for the first time. We observed that these mutants lack external O-PS yet trigger changes in genetic transcription and in phenotypic properties associated with the outer membrane and cell wall. The three mutants are highly attenuated; unexpectedly, Rev1Δwzm also excels as an immunogenic and effective vaccine against B. melitensis and Brucella ovis in mice, revealing that low persistence is not at odds with efficacy. Rev1Δwzm is attenuated in BeWo trophoblasts, does not infect mouse placentas, and is safe in pregnant ewes. Overall, these attributes and the minimal serological interference induced in sheep make Rev1Δwzm a highly promising vaccine candidate.
Collapse
Affiliation(s)
- Sara Mena-Bueno
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
- Agronomy, Biotecnology and Food Department, Universidad Pública de Navarra (UPNA), Pamplona, Spain
| | - Irati Poveda-Urkixo
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
| | - Oihane Irazoki
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Leyre Palacios
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Ana Zabalza-Baranguá
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
| | - María Jesús Grilló
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
- *Correspondence: María Jesús Grilló,
| |
Collapse
|
8
|
Junot G, Darnige T, Lindner A, Martinez VA, Arlt J, Dawson A, Poon WCK, Auradou H, Clément E. Run-to-Tumble Variability Controls the Surface Residence Times of E. coli Bacteria. PHYSICAL REVIEW LETTERS 2022; 128:248101. [PMID: 35776449 DOI: 10.1103/physrevlett.128.248101] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 04/19/2022] [Indexed: 06/15/2023]
Abstract
Motile bacteria are known to accumulate at surfaces, eventually leading to changes in bacterial motility and biofilm formation. We use a novel two-color, three-dimensional Lagrangian tracking technique to follow simultaneously the body and the flagella of a wild-type Escherichia coli. We observe long surface residence times and surface escape corresponding mostly to immediately antecedent tumbling. A motility model accounting for a large behavioral variability in run-time duration reproduces all experimental findings and gives new insights into surface trapping efficiency.
Collapse
Affiliation(s)
- Gaspard Junot
- PMMH, UMR 7636 CNRS, ESPCI Paris, PSL Research University, Sorbonne Université and Université Paris Cité, 7-9 quai Saint-Bernard, Paris, 75005, France
| | - Thierry Darnige
- PMMH, UMR 7636 CNRS, ESPCI Paris, PSL Research University, Sorbonne Université and Université Paris Cité, 7-9 quai Saint-Bernard, Paris, 75005, France
| | - Anke Lindner
- PMMH, UMR 7636 CNRS, ESPCI Paris, PSL Research University, Sorbonne Université and Université Paris Cité, 7-9 quai Saint-Bernard, Paris, 75005, France
| | - Vincent A Martinez
- SUPA and the School of Physics and Astronomy, The University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom
| | - Jochen Arlt
- SUPA and the School of Physics and Astronomy, The University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom
| | - Angela Dawson
- SUPA and the School of Physics and Astronomy, The University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom
| | - Wilson C K Poon
- SUPA and the School of Physics and Astronomy, The University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom
| | - Harold Auradou
- Université Paris-Saclay, CNRS, FAST, 91405 Orsay, France
| | - Eric Clément
- PMMH, UMR 7636 CNRS, ESPCI Paris, PSL Research University, Sorbonne Université and Université Paris Cité, 7-9 quai Saint-Bernard, Paris, 75005, France
- Institut Universitaire de France (IUF)
| |
Collapse
|
9
|
Corbin Goodman LC, Erickson HP. FtsZ at mid-cell is essential in Escherichia coli until the late stage of constriction. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35679326 DOI: 10.1099/mic.0.001194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
There has been recent debate as to the source of constriction force during cell division. FtsZ can generate a constriction force on tubular membranes in vitro, suggesting it may generate the constriction force in vivo. However, another study showed that mutants of FtsZ did not affect the rate of constriction, whereas mutants of the PG assembly did, suggesting that PG assembly may push the constriction from the outside. Supporting this model, two groups found that cells that have initiated constriction can complete septation while the Z ring is poisoned with the FtsZ targeting antibiotic PC190723. PC19 arrests treadmilling but leaves FtsZ in place. We sought to determine if a fully assembled Z ring is necessary during constriction. To do this, we used a temperature-sensitive FtsZ mutant, FtsZ84. FtsZ84 supports cell division at 30 °C, but it disassembles from the Z ring within 1 min upon a temperature jump to 42 °C. Following the temperature jump we found that cells in early constriction stop constricting. Cells that had progressed to the later stage of division finished constriction without a Z ring. These results show that in Escherichia coli, an assembled Z ring is essential for constriction except in the final stage, contradicting the simplest interpretation of previous studies using PC19.
Collapse
Affiliation(s)
| | - Harold P Erickson
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA.,Department of Cell Biology, Duke University, Durham, North Carolina, USA
| |
Collapse
|
10
|
Cai J, Wang S, Gao Y, Wang Q. Antibacterial Activity and Mechanism of Polygonum orientale L. Essential Oil against Pectobacterium carotovorum subsp. carotovorum. Foods 2022; 11:foods11111585. [PMID: 35681334 PMCID: PMC9180537 DOI: 10.3390/foods11111585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 05/20/2022] [Accepted: 05/25/2022] [Indexed: 11/16/2022] Open
Abstract
Infected by Pectobacterium carotovorum subsp. carotovorum (Pcc), the quality of Chinese cabbage could severely decline. Using chemical bactericides to control Pcc could cause food safety problems. Thus, we investigated the optimum extraction conditions, antibacterial activity, chemical compounds and antibacterial mechanism of Polygonum orientale L. essential oil (POEO) against Pcc in order to search a new way to control Pcc. The optimum extraction conditions of POEO (soaking time 2.6 h, extraction time 7.7 h and ratio of liquid to solid 10.3 mL/g) were optimized by response surface methodology. The minimum inhibitory concentration (MIC) of POEO against Pcc was 0.625 mg/mL. The control efficiency of protective activity of POEO against Pcc was 74.67~92.67%, and its curative activity was 76.00~93.00%. Then, 29 compounds were obtained by GC-MS; the prime compounds of POEO were phytol, phytone, n-pentacosane, 1-octen-3-ol and β-ionone. It was verified that, compared with control samples, POEO destroyed cell morphology. It increased surface potential, increased hydrophobicity, damaged cell walls, destroyed the integrity and permeability of cell membrane, reduced membrane potential (MP), and changed membrane protein conformation. It inhibited the activities of pyruvate kinase (PK), succinate dehydrogenase (SDH) and adenosine triphosphatase (ATPase). Briefly, the results of this study demonstrate that POEO showed effective inhibitory activity against Pcc, thus POEO could have potential application in controlling Pcc.
Collapse
Affiliation(s)
- Jin Cai
- Institute of Applied Chemistry, Shanxi University, No. 92 Wucheng Road, Taiyuan 030006, China
- Correspondence:
| | - Shiqin Wang
- Modern Research Center for Traditional Chinese Medicine, Shanxi University, No. 92 Wucheng Road, Taiyuan 030006, China;
- The Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Shanxi University, No. 92 Wucheng Road, Taiyuan 030006, China
| | - Yichen Gao
- School of Life Science, Shanxi University, No. 92 Wucheng Road, Taiyuan 030006, China; (Y.G.); (Q.W.)
| | - Qi Wang
- School of Life Science, Shanxi University, No. 92 Wucheng Road, Taiyuan 030006, China; (Y.G.); (Q.W.)
| |
Collapse
|
11
|
Filbrun AB, Richardson JC, Khanal PC, Tzeng Y, Dickson RM. Rapid, label‐free antibiotic susceptibility determined directly from positive blood culture. Cytometry A 2022; 101:564-576. [DOI: 10.1002/cyto.a.24560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 03/19/2022] [Accepted: 04/06/2022] [Indexed: 11/12/2022]
Affiliation(s)
- Alexandra B. Filbrun
- School of Chemistry and Biochemistry and Petit Institute of Bioengineering and Bioscience Georgia Institute of Technology Atlanta GA
| | - Joseph C. Richardson
- School of Chemistry and Biochemistry and Petit Institute of Bioengineering and Bioscience Georgia Institute of Technology Atlanta GA
| | - Prakash C. Khanal
- School of Chemistry and Biochemistry and Petit Institute of Bioengineering and Bioscience Georgia Institute of Technology Atlanta GA
| | - Yih‐Ling Tzeng
- Division of Infectious Disease, Department of Medicine Emory University School of Medicine Atlanta GA
| | - Robert M. Dickson
- School of Chemistry and Biochemistry and Petit Institute of Bioengineering and Bioscience Georgia Institute of Technology Atlanta GA
| |
Collapse
|
12
|
Mandela E, Stubenrauch CJ, Ryoo D, Hwang H, Cohen EJ, Torres VVL, Deo P, Webb CT, Huang C, Schittenhelm RB, Beeby M, Gumbart JC, Lithgow T, Hay ID. Adaptation of the periplasm to maintain spatial constraints essential for cell envelope processes and cell viability. eLife 2022; 11:73516. [PMID: 35084330 PMCID: PMC8824477 DOI: 10.7554/elife.73516] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 01/21/2022] [Indexed: 11/17/2022] Open
Abstract
The cell envelope of Gram-negative bacteria consists of two membranes surrounding a periplasm and peptidoglycan layer. Molecular machines spanning the cell envelope depend on spatial constraints and load-bearing forces across the cell envelope and surface. The mechanisms dictating spatial constraints across the cell envelope remain incompletely defined. In Escherichia coli, the coiled-coil lipoprotein Lpp contributes the only covalent linkage between the outer membrane and the underlying peptidoglycan layer. Using proteomics, molecular dynamics, and a synthetic lethal screen, we show that lengthening Lpp to the upper limit does not change the spatial constraint but is accommodated by other factors which thereby become essential for viability. Our findings demonstrate E. coli expressing elongated Lpp does not simply enlarge the periplasm in response, but the bacteria accommodate by a combination of tilting Lpp and reducing the amount of the covalent bridge. By genetic screening, we identified all of the genes in E. coli that become essential in order to enact this adaptation, and by quantitative proteomics discovered that very few proteins need to be up- or down-regulated in steady-state levels in order to accommodate the longer Lpp. We observed increased levels of factors determining cell stiffness, a decrease in membrane integrity, an increased membrane vesiculation and a dependance on otherwise non-essential tethers to maintain lipid transport and peptidoglycan biosynthesis. Further this has implications for understanding how spatial constraint across the envelope controls processes such as flagellum-driven motility, cellular signaling, and protein translocation
Collapse
Affiliation(s)
- Eric Mandela
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | | | - David Ryoo
- Interdisciplinary Bioengineering Graduate Program, Georgia Institute of Technology, Atlanta, United States
| | - Hyea Hwang
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States
| | - Eli J Cohen
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | | | - Pankaj Deo
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Chaille T Webb
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Cheng Huang
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Ralf B Schittenhelm
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Morgan Beeby
- Department of Life Sciencesa, Imperial College London, London, United Kingdom
| | - James C Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, United States
| | - Trevor Lithgow
- Department of Microbiology, Monash University, Melbourne, Australia
| | - Iain D Hay
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| |
Collapse
|
13
|
Cao Y, Li L, Zhang Y, Liu F, Xiao X, Li X, Yu Y. Evaluation of Cronobacter sakazakii biofilm formation after sdiA knockout in different osmotic pressure conditions. Food Res Int 2022; 151:110886. [PMID: 34980413 DOI: 10.1016/j.foodres.2021.110886] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/23/2021] [Accepted: 12/02/2021] [Indexed: 12/26/2022]
Abstract
This study characterizes the impact of sdiA on biofilm formation under normal or osmotic stress conditions in Cronobacter sakazakii by constructing a sdiA deletion mutant (ΔsdiA). Here, the downregulation of flagellar assembly-related genes and upregulation of capsular, cellulose and lipopolysaccharide biosynthesis-associated genes in ΔsdiA were observed when compared to the wild type strain (WT) through transcriptomic analysis. Meanwhile, reduced ability of motility, enhanced cell surface hydrophobicity and stronger biofilms with extracellular matrix were observed in WT with deletion of sdiA. Both WT and ΔsdiA formed more biofilm in low osmotic stress medium, while in hyperosmolarity conditions, formation of biofilm was dramatically reduced. Our findings supported that sdiA might suppress biofilm formation of C. sakazakii by regulating biosynthesis of flagellar and extracellular polymeric substances. This study investigates the role of sdiA on biofilm formation in C. sakazakii, and provides the basis for the inhibition of C. sakazakii in food industry and infant-feeding.
Collapse
Affiliation(s)
- Yifang Cao
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Li Li
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Yan Zhang
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Fengsong Liu
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Xinglong Xiao
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China.
| | - Xiaofeng Li
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Yigang Yu
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China.
| |
Collapse
|
14
|
Dahal D, Ojha KR, Pokhrel S, Paruchuri S, Konopka M, Liu Q, Pang Y. NIR-emitting styryl dyes with large Stokes' shifts for imaging application: From cellular plasma membrane, mitochondria to Zebrafish neuromast. DYES AND PIGMENTS : AN INTERNATIONAL JOURNAL 2021; 194:109629. [PMID: 34366501 PMCID: PMC8345024 DOI: 10.1016/j.dyepig.2021.109629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Near-infrared (NIR) emitting probes with very large Stokes' shifts play a crucial role in bioimaging applications, as the optical signals in this region exhibit high signal to background ratio and allow deeper tissue penetration. Herein we illustrate NIR-emitting probe 2 with very large Stokes' shifts (Δλ ≈ 260 - 272 nm) by integrating the excited-state intramolecular proton transfer (ESIPT) unit 2-(2'-hydroxyphenyl)benzoxazole (HBO) into a pyridinium derived cyanine. The ESIPT not only enhances the Stokes' shifts but also improves the quantum efficiency of the probe 2 (фfl = 0.27 - 0.40 in DCM). The application of 2 in live cells imaging reveals that compound 2 stains mitochondria in eukaryotic cells, normal human lungs fibroblast (NHLF), Zebrafish's neuromast hair cells, and support cells, and inner plasma membrane in prokaryotic cells, Escherichia coli (E. coli).
Collapse
Affiliation(s)
- Dipendra Dahal
- Department of Chemistry, The University of Akron, Akron, OH 44325, USA
| | - Krishna R Ojha
- Department of Chemistry, The University of Akron, Akron, OH 44325, USA
| | - Sabita Pokhrel
- Department of Chemistry, The University of Akron, Akron, OH 44325, USA
| | - Sailaja Paruchuri
- Department of Chemistry, The University of Akron, Akron, OH 44325, USA
| | - Michael Konopka
- Department of Chemistry, The University of Akron, Akron, OH 44325, USA
| | - Qin Liu
- Department of Biology, The University of Akron, Akron, OH 44325, USA
| | - Yi Pang
- Department of Chemistry, The University of Akron, Akron, OH 44325, USA
- Maurice Morton Institute of Polymer Science, The University of Akron, Akron, OH 44325, USA
| |
Collapse
|
15
|
Sun J, Shi H, Huang KC. Hyperosmotic Shock Transiently Accelerates Constriction Rate in Escherichia coli. Front Microbiol 2021; 12:718600. [PMID: 34489908 PMCID: PMC8418109 DOI: 10.3389/fmicb.2021.718600] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 07/26/2021] [Indexed: 11/13/2022] Open
Abstract
Bacterial cells in their natural environments encounter rapid and large changes in external osmolality. For instance, enteric bacteria such as Escherichia coli experience a rapid decrease when they exit from host intestines. Changes in osmolality alter the mechanical load on the cell envelope, and previous studies have shown that large osmotic shocks can slow down bacterial growth and impact cytoplasmic diffusion. However, it remains unclear how cells maintain envelope integrity and regulate envelope synthesis in response to osmotic shocks. In this study, we developed an agarose pad-based protocol to assay envelope stiffness by measuring population-averaged cell length before and after a hyperosmotic shock. Pad-based measurements exhibited an apparently larger length change compared with single-cell dynamics in a microfluidic device, which we found was quantitatively explained by a transient increase in division rate after the shock. Inhibiting cell division led to consistent measurements between agarose pad-based and microfluidic measurements. Directly after hyperosmotic shock, FtsZ concentration and Z-ring intensity increased, and the rate of septum constriction increased. These findings establish an agarose pad-based protocol for quantifying cell envelope stiffness, and demonstrate that mechanical perturbations can have profound effects on bacterial physiology.
Collapse
Affiliation(s)
- Jiawei Sun
- Department of Bioengineering, Stanford University, Stanford, CA, United States
| | - Handuo Shi
- Department of Bioengineering, Stanford University, Stanford, CA, United States.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, United States
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA, United States.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, United States.,Chan Zuckerberg Biohub, San Francisco, CA, United States
| |
Collapse
|
16
|
Gao X, Qiu S, Lin Z, Xie X, Yin W, Lu X. Carbon-Based Composites as Anodes for Microbial Fuel Cells: Recent Advances and Challenges. Chempluschem 2021; 86:1322-1341. [PMID: 34363342 DOI: 10.1002/cplu.202100292] [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: 06/28/2021] [Revised: 07/29/2021] [Indexed: 11/11/2022]
Abstract
Owing to the low price, chemical stability and good conductivity, carbon-based materials have been extensively applied as the anode in microbial fuel cells (MFCs). In this review, apart from the charge storage mechanism and anode requirements, the major work focuses on five categories of carbon-based anode materials (traditional carbon, porous carbon, nano-carbon, metal/carbon composite and polymer/carbon composite). The relationship is demonstrated in depth between the physicochemical properties of the anode surface/interface/bulk (porosity, surface area, hydrophilicity, partical size, charge, roughness, etc.) and the bioelectrochemical performances (electron transfer, electrolyte diffusion, capacitance, toxicity, start-up time, current, power density, voltage, etc.). An outlook for future work is also proposed.
Collapse
Affiliation(s)
- Xingyuan Gao
- Faculty of Chemistry and Material Science, Engineering Technology Development Center of Advanced Materials &, Energy Saving and Emission Reduction, in Guangdong Colleges and Universities, Guangdong University of Education, Guangzhou, 510303, P. R. China.,MOE of the Key Laboratory of Bioinorganic and Synthetic Chemistry, The Key Lab of Low-carbon Chem &, Energy Conservation of Guangdong Province, School of Chemistry, Sun Yat-Sen University, Guangzhou, 510275, P. R. China
| | - Shuxian Qiu
- Faculty of Chemistry and Material Science, Engineering Technology Development Center of Advanced Materials &, Energy Saving and Emission Reduction, in Guangdong Colleges and Universities, Guangdong University of Education, Guangzhou, 510303, P. R. China
| | - Ziting Lin
- Faculty of Chemistry and Material Science, Engineering Technology Development Center of Advanced Materials &, Energy Saving and Emission Reduction, in Guangdong Colleges and Universities, Guangdong University of Education, Guangzhou, 510303, P. R. China
| | - Xiangjuan Xie
- Faculty of Chemistry and Material Science, Engineering Technology Development Center of Advanced Materials &, Energy Saving and Emission Reduction, in Guangdong Colleges and Universities, Guangdong University of Education, Guangzhou, 510303, P. R. China
| | - Wei Yin
- Faculty of Chemistry and Material Science, Engineering Technology Development Center of Advanced Materials &, Energy Saving and Emission Reduction, in Guangdong Colleges and Universities, Guangdong University of Education, Guangzhou, 510303, P. R. China
| | - Xihong Lu
- MOE of the Key Laboratory of Bioinorganic and Synthetic Chemistry, The Key Lab of Low-carbon Chem &, Energy Conservation of Guangdong Province, School of Chemistry, Sun Yat-Sen University, Guangzhou, 510275, P. R. China
| |
Collapse
|
17
|
Ramalakshmi S, Ramanan RN, Madhavan S, Ooi CW, Chang CCH, Harper IS, Lewis DM, Lee AK, He L, Seenichamy A. Investigation of selective release of periplasmic proteins through pore size analysis and single-cell microscopy in Escherichia coli. Biochem Eng J 2021. [DOI: 10.1016/j.bej.2021.108009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
18
|
Erickson HP. How Teichoic Acids Could Support a Periplasm in Gram-Positive Bacteria, and Let Cell Division Cheat Turgor Pressure. Front Microbiol 2021; 12:664704. [PMID: 34040598 PMCID: PMC8141598 DOI: 10.3389/fmicb.2021.664704] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/06/2021] [Indexed: 12/17/2022] Open
Abstract
The cytoplasm of bacteria is maintained at a higher osmolality than the growth medium, which generates a turgor pressure. The cell membrane (CM) cannot support a large turgor, so there are two possibilities for transferring the pressure to the peptidoglycan cell wall (PGW): (1) the CM could be pressed directly against the PGW, or (2) the CM could be separated from the PGW by a periplasmic space that is isoosmotic with the cytoplasm. There is strong evidence for gram-negative bacteria that a periplasm exists and is isoosmotic with the cytoplasm. No comparable studies have been done for gram-positive bacteria. Here I suggest that a periplasmic space is probably essential in order for the periplasmic proteins to function, including especially the PBPs that remodel the peptidoglycan wall. I then present a semi-quantitative analysis of how teichoic acids could support a periplasm that is isoosmotic with the cytoplasm. The fixed anionic charge density of teichoic acids in the periplasm is ∼0.5 M, which would bring in ∼0.5 M Na+ neutralizing ions. This approximately balances the excess osmolality of the cytoplasm that would produce a turgor pressure of 19 atm. The 0.5 M fixed charge density is similar to that of proteoglycans in articular cartilage, suggesting a comparability ability to support pressure. An isoosmotic periplasm would be especially important for cell division, since it would allow CM constriction and PGW synthesis to avoid turgor pressure.
Collapse
Affiliation(s)
- Harold P Erickson
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States
| |
Collapse
|
19
|
Rank LA, Agrawal A, Liu L, Zhu Y, Mustafi M, Weisshaar JC, Gellman SH. Diverse Impacts on Prokaryotic and Eukaryotic Membrane Activities from Hydrophobic Subunit Variation Among Nylon-3 Copolymers. ACS Chem Biol 2021; 16:176-184. [PMID: 33305582 DOI: 10.1021/acschembio.0c00855] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Synthetic, sequence-random polymers that feature a wide range of backbone and side chain structures have been reported to function as mimics of natural host-defense peptides, inhibiting bacterial growth while exerting little or no toxicity toward eukaryotic cells. The common themes among these materials are net positive charge, which is thought to confer preferential action toward prokaryotic vs eukaryotic cells, and the presence of hydrophobic components, which are thought to mediate membrane disruption. This study is based on a set of new binary cationic-hydrophobic nylon-3 copolymers that was designed to ask whether factors beyond net charge and net hydrophobicity influence the biological activity profile. In previous work, we found that nonpolar subunits preorganized by a ring led to copolymers with a diminished tendency to disrupt human cell membranes (as measured via lysis of red blood cells) relative to copolymers containing more flexible nonpolar subunits. An alternative mode of conformational restriction, involving geminal substitution, also minimized hemolysis. Here, we asked whether combining a cyclic constraint and geminal substitution would be synergistic; the combination was achieved by introducing backbone methyl groups to previously described cyclopentyl and cyclohexyl subunits. The new cyclic subunits containing two quaternary backbone carbons (i.e, two sites of geminal substitution) were comparable or slightly superior in terms of antibacterial potency but markedly superior in terms of low hemolytic activity, relative to cyclic subunits lacking the quaternary carbons. However, new cyclic units containing only one quaternary carbon were very hemolytic, which was unanticipated. Variations in net hydrophobicity cannot explain the trend in hemolysis, in contrast to the standard perspective in this field. The impact of each new polymer on live E. coli cells was evaluated via fluorescence microscopy. All new polymers moved rapidly across the outer membrane without large-scale disruption of barrier function. Increasing the number of quaternary carbons in the nonpolar subunit correlated with an increased propensity to permeabilize the cytoplasmic membrane of E. coli cells. Collectively, these findings show that relationships between nonpolar subunit identity and biological activity are influenced by factors in addition to hydrophobicity and charge. We propose that the variation of subunit conformational properties may be one such factor.
Collapse
|
20
|
Ultee E, Zhong X, Shitut S, Briegel A, Claessen D. Formation of wall-less cells in Kitasatospora viridifaciens requires cytoskeletal protein FilP in oxygen-limiting conditions. Mol Microbiol 2020; 115:1181-1190. [PMID: 33278050 PMCID: PMC8359286 DOI: 10.1111/mmi.14662] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 12/01/2020] [Accepted: 12/01/2020] [Indexed: 02/07/2023]
Abstract
The cell wall is considered an essential component for bacterial survival, providing structural support, and protection from environmental insults. Under normal growth conditions, filamentous actinobacteria insert new cell wall material at the hyphal tips regulated by the coordinated activity of cytoskeletal proteins and cell wall biosynthetic enzymes. Despite the importance of the cell wall, some filamentous actinobacteria can produce wall‐deficient S‐cells upon prolonged exposure to hyperosmotic stress. Here, we performed cryo‐electron tomography and live cell imaging to further characterize S‐cell extrusion in Kitasatospora viridifaciens. We show that exposure to hyperosmotic stress leads to DNA compaction, membrane and S‐cell extrusion, and thinning of the cell wall at hyphal tips. Additionally, we find that the extrusion of S‐cells is abolished in a cytoskeletal mutant strain that lacks the intermediate filament‐like protein FilP. Furthermore, micro‐aerobic culturing promotes the formation of S‐cells in the wild type, but the limited oxygen still impedes S‐cell formation in the ΔfilP mutant. These results demonstrate that S‐cell formation is stimulated by oxygen‐limiting conditions and dependent on functional cytoskeleton remodeling.
Collapse
Affiliation(s)
- Eveline Ultee
- Department of Molecular Biotechnology, Institute of Biology, Leiden University, Leiden, The Netherlands.,Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands
| | - Xiaobo Zhong
- Department of Molecular Biotechnology, Institute of Biology, Leiden University, Leiden, The Netherlands.,Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands
| | - Shraddha Shitut
- Department of Molecular Biotechnology, Institute of Biology, Leiden University, Leiden, The Netherlands.,Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands
| | - Ariane Briegel
- Department of Molecular Biotechnology, Institute of Biology, Leiden University, Leiden, The Netherlands.,Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands
| | - Dennis Claessen
- Department of Molecular Biotechnology, Institute of Biology, Leiden University, Leiden, The Netherlands.,Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands
| |
Collapse
|
21
|
Masoura M, Passaretti P, Overton TW, Lund PA, Gkatzionis K. Use of a model to understand the synergies underlying the antibacterial mechanism of H 2O 2-producing honeys. Sci Rep 2020; 10:17692. [PMID: 33077785 PMCID: PMC7573686 DOI: 10.1038/s41598-020-74937-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 10/07/2020] [Indexed: 12/30/2022] Open
Abstract
Honey has been valued as a powerful antimicrobial since ancient times. However, the understanding of the underlying antibacterial mechanism is incomplete. The complexity and variability of honey composition represent a challenge to this scope. In this study, a simple model system was used to investigate the antibacterial effect of, and possible synergies between, the three main stressors present in honey: sugars, gluconic acid, and hydrogen peroxide (H2O2), which result from the enzymatic conversion of glucose on honey dilution. Our results demonstrated that the synergy of H2O2 and gluconic acid is essential for the antibacterial activity of honey. This synergy caused membrane depolarization, destruction of the cell wall, and eventually growth inhibition of E. coli K-12. The presence of H2O2 stimulated the generation of other long-lived ROS in a dose-dependent manner. Sugars caused osmosis-related morphological changes, however, decreased the toxicity of the H2O2/gluconic acid. The susceptibility of catalase and general stress response sigma factor mutants confirmed the synergy of the three stressors, which is enhanced at higher H2O2 concentrations. By monitoring cellular phenotypic changes caused by model honey, we explained how this can be bactericidal even though the antimicrobial compounds which it contains are at non-inhibitory concentrations.
Collapse
Affiliation(s)
- Maria Masoura
- School of Chemical Engineering, University of Birmingham, Birmingham, B15 2SA, UK.,Institute of Microbiology and Infection (IMI), University of Birmingham, Birmingham, B15 2SA, UK
| | - Paolo Passaretti
- School of Chemical Engineering, University of Birmingham, Birmingham, B15 2SA, UK
| | - Tim W Overton
- School of Chemical Engineering, University of Birmingham, Birmingham, B15 2SA, UK
| | - Pete A Lund
- Institute of Microbiology and Infection (IMI), University of Birmingham, Birmingham, B15 2SA, UK
| | - Konstantinos Gkatzionis
- School of Chemical Engineering, University of Birmingham, Birmingham, B15 2SA, UK. .,Department of Food Science and Nutrition, School of the Environment, University of the Aegean, Lemnos, Greece.
| |
Collapse
|
22
|
Passos TF, Souza MT, Zanotto ED, de Souza CWO. Bactericidal activity and biofilm inhibition of F18 bioactive glass against Staphylococcus aureus. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 118:111475. [PMID: 33255054 DOI: 10.1016/j.msec.2020.111475] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 08/22/2020] [Accepted: 08/28/2020] [Indexed: 02/06/2023]
Abstract
Antimicrobial treatment failure has been increasing at alarming rates. In this context, the bactericidal properties of biocompatible antimicrobial agents have been widely studied. F18 is a recently developed bioactive glass that presents a much wider working range when compared to other bioactive glasses, a feature that allows it to be used for coating metallic implants, sintering scaffolds or manufacturing fibers for wound healing applications. The aim of this study was to investigate the in vitro bactericidal and anti-biofilm activity of F18 glass as a powder and as a coating on steel samples, and to explore the effects of its dissolution products at concentrations from 3 mg/mL to 50 mg/mL against the Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) biofilms. Furthermore, we intend to verify whether changes in the medium pH could influence the bactericidal activity of F18. The results indicated that F18 presented bactericidal activity in preformed S. aureus and MRSA biofilms, reducing more than 6 logs of the viable cells that remained in contact with 50 mg/mL for 24 h. Moreover, an anti-biofilm activity was observed after 12 h of direct contact, with a drop of more than 6 logs of the viable bacterial population. Neutralization of the F18 solution pH decreased its bactericidal efficacy. These results indicate that the F18 glass could be considered as an alternative material for controlling and treating infections by S. aureus.
Collapse
Affiliation(s)
- Tathiane Ferroni Passos
- Biotechnology Graduate Program (PPGBiotec-UFSCar), Federal University of São Carlos, SP, Brazil; Microbiology and Parasitology Laboratory (LMP), Department of Morphology and Pathology, Federal University of São Carlos, SP, Brazil.
| | - Marina Trevelin Souza
- Vitreous Materials Laboratory (LaMaV), Department of Materials Engineering, Federal University of São Carlos, SP, Brazil
| | - Edgar Dutra Zanotto
- Vitreous Materials Laboratory (LaMaV), Department of Materials Engineering, Federal University of São Carlos, SP, Brazil
| | - Clovis Wesley Oliveira de Souza
- Biotechnology Graduate Program (PPGBiotec-UFSCar), Federal University of São Carlos, SP, Brazil; Microbiology and Parasitology Laboratory (LMP), Department of Morphology and Pathology, Federal University of São Carlos, SP, Brazil.
| |
Collapse
|
23
|
Lipoprotein Lpp regulates the mechanical properties of the E. coli cell envelope. Nat Commun 2020; 11:1789. [PMID: 32286264 PMCID: PMC7156740 DOI: 10.1038/s41467-020-15489-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 03/09/2020] [Indexed: 12/16/2022] Open
Abstract
The mechanical properties of the cell envelope in Gram-negative bacteria are controlled by the peptidoglycan, the outer membrane, and the proteins interacting with both layers. In Escherichia coli, the lipoprotein Lpp provides the only covalent crosslink between the outer membrane and the peptidoglycan. Here, we use single-cell atomic force microscopy and genetically engineered strains to study the contribution of Lpp to cell envelope mechanics. We show that Lpp contributes to cell envelope stiffness in two ways: by covalently connecting the outer membrane to the peptidoglycan, and by controlling the width of the periplasmic space. Furthermore, mutations affecting Lpp function substantially increase bacterial susceptibility to the antibiotic vancomycin, indicating that Lpp-dependent effects can affect antibacterial drug efficacy. Lipoprotein Lpp provides a covalent crosslink between the outer membrane and the peptidoglycan in E. coli. Here, the authors use atomic force microscopy to show that Lpp contributes to cell envelope stiffness by covalently connecting the two layers and by controlling the width of the periplasmic space.
Collapse
|
24
|
Yang D, Männik J, Retterer ST, Männik J. The effects of polydisperse crowders on the compaction of the Escherichia coli nucleoid. Mol Microbiol 2020; 113:1022-1037. [PMID: 31961016 DOI: 10.1111/mmi.14467] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 01/15/2020] [Accepted: 01/15/2020] [Indexed: 01/10/2023]
Abstract
DNA binding proteins, supercoiling, macromolecular crowders, and transient DNA attachments to the cell membrane have all been implicated in the organization of the bacterial chromosome. However, it is unclear what role these factors play in compacting the bacterial DNA into a distinct organelle-like entity, the nucleoid. By analyzing the effects of osmotic shock and mechanical squeezing on Escherichia coli, we show that macromolecular crowders play a dominant role in the compaction of the DNA into the nucleoid. We find that a 30% increase in the crowder concentration from physiological levels leads to a three-fold decrease in the nucleoid's volume. The compaction is anisotropic, being higher along the long axes of the cell at low crowding levels. At higher crowding levels, the nucleoid becomes spherical, and its compressibility decreases significantly. Furthermore, we find that the compressibility of the nucleoid is not significantly affected by cell growth rates and by prior treatment with rifampicin. The latter results point out that in addition to poly ribosomes, soluble cytoplasmic proteins have a significant contribution in determining the size of the nucleoid. The contribution of poly ribosomes dominates at faster and soluble proteins at slower growth rates.
Collapse
Affiliation(s)
- Da Yang
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN, USA
| | - Jaana Männik
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN, USA.,Department of Biochemistry, and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, USA
| | - Scott T Retterer
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Jaan Männik
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN, USA
| |
Collapse
|
25
|
Paraschiv A, Hegde S, Ganti R, Pilizota T, Šarić A. Dynamic Clustering Regulates Activity of Mechanosensitive Membrane Channels. PHYSICAL REVIEW LETTERS 2020; 124:048102. [PMID: 32058787 DOI: 10.1103/physrevlett.124.048102] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Indexed: 06/10/2023]
Abstract
Experiments have suggested that bacterial mechanosensitive channels separate into 2D clusters, the role of which is unclear. By developing a coarse-grained computer model we find that clustering promotes the channel closure, which is highly dependent on the channel concentration and membrane stress. This behaviour yields a tightly regulated gating system, whereby at high tensions channels gate individually, and at lower tensions the channels spontaneously aggregate and inactivate. We implement this positive feedback into the model for cell volume regulation, and find that the channel clustering protects the cell against excessive loss of cytoplasmic content.
Collapse
Affiliation(s)
- Alexandru Paraschiv
- Department of Physics and Astronomy, Institute for the Physics of Living Systems University College London, London WC1E 6BT, United Kingdom
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom
| | - Smitha Hegde
- Centre for Synthetic and Systems Biology University of Edinburgh, Edinburgh EH9 3FF, United Kingdom
| | - Raman Ganti
- Institute for Medical Engineering and Science Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Teuta Pilizota
- Centre for Synthetic and Systems Biology University of Edinburgh, Edinburgh EH9 3FF, United Kingdom
| | - Anđela Šarić
- Department of Physics and Astronomy, Institute for the Physics of Living Systems University College London, London WC1E 6BT, United Kingdom
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom
| |
Collapse
|
26
|
Li Z, Yang S, Song Y, Xu H, Wang Z, Wang W, Zhao Y. Performance evaluation of treating oil-containing restaurant wastewater in microbial fuel cell using in situ graphene/polyaniline modified titanium oxide anode. ENVIRONMENTAL TECHNOLOGY 2020; 41:420-429. [PMID: 30015569 DOI: 10.1080/09593330.2018.1499814] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/06/2018] [Indexed: 06/08/2023]
Abstract
Most studies conducted nowadays to boost electrode performance in microbial fuel cell (MFC) have focused on carbonaceous materials. The titanium suboxides (Ti4O7, TS) are able to provide a new alternative for achieving better performance in MFC and have been tested and demonstrated in this study. The Ti4O7 electrode with high electrochemical activity was modified by graphene/polyaniline by the constant potential method. Electrogenic microorganisms were more conducive to adhere to the anode electrode due to the presence of graphene/polyaniline. The MFC reactor with polyaniline /graphene modified TS (TSGP) anode achieves the highest voltage with 980 mV, and produces a peak power density of 2073 mW/m2, which is 2.9 and 12.7 times of those with the carbon cloth anode, respectively, at the 1000 Ω external resistance. In addition, this study evaluates the effects of anolyte conductivity, pH, and COD on the treatment of oil-containing restaurant wastewater (OCRW) in MFC using TSGP anode. The OCRW amended with 120 mS/cm obtains the lowest internal resistance (160.3 Ω). Increasing the anodic pH, gradually from acidic (pH 5.5) to alkaline conditions (pH 8.0), resulted in a gradual increase in maximum power density to 576.4 mW/m2 and a decrease in internal cell resistance to 203.7 Ω. The MFC at the COD 1500 mg/L could obtain steady-state output voltage during 103 h while removing up to 65.2% of the COD of the OCRW.
Collapse
Affiliation(s)
- ZhiLiang Li
- Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas, Ministry of Education, Chang'an University, Xi'an, People's Republic of China
- School of Environment and Energy, South China University of Technology, Guangzhou, People's Republic of China
| | - ShengKe Yang
- Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas, Ministry of Education, Chang'an University, Xi'an, People's Republic of China
| | - Ya'nan Song
- Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas, Ministry of Education, Chang'an University, Xi'an, People's Republic of China
| | - HaiYang Xu
- Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas, Ministry of Education, Chang'an University, Xi'an, People's Republic of China
| | - ZongZhou Wang
- Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas, Ministry of Education, Chang'an University, Xi'an, People's Republic of China
| | - WenKe Wang
- Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas, Ministry of Education, Chang'an University, Xi'an, People's Republic of China
| | - YaQian Zhao
- UCD Dooge Centre for Water Resources Research, School of Civil Engineering, University College Dublin, Dublin, Ireland
| |
Collapse
|
27
|
Wang YK, Krasnopeeva E, Lin SY, Bai F, Pilizota T, Lo CJ. Comparison of Escherichia coli surface attachment methods for single-cell microscopy. Sci Rep 2019; 9:19418. [PMID: 31857669 PMCID: PMC6923479 DOI: 10.1038/s41598-019-55798-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Accepted: 11/05/2019] [Indexed: 12/22/2022] Open
Abstract
For in vivo, single-cell imaging bacterial cells are commonly immobilised via physical confinement or surface attachment. Different surface attachment methods have been used both for atomic force and optical microscopy (including super resolution), and some have been reported to affect bacterial physiology. However, a systematic comparison of the effects these attachment methods have on the bacterial physiology is lacking. Here we present such a comparison for bacterium Escherichia coli, and assess the growth rate, size and intracellular pH of cells growing attached to different, commonly used, surfaces. We demonstrate that E. coli grow at the same rate, length and internal pH on all the tested surfaces when in the same growth medium. The result suggests that tested attachment methods can be used interchangeably when studying E. coli physiology.
Collapse
Affiliation(s)
- Yao-Kuan Wang
- Department of Physics and Graduate Institute of Biophysics, National Central University, Jhongli, Taiwan, 32001, Republic of China
| | - Ekaterina Krasnopeeva
- Centre for Synthetic and Systems Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Alexander Crum Brown Road, EH9 3FF, Edinburgh, UK
| | - Ssu-Yuan Lin
- Department of Physics and Graduate Institute of Biophysics, National Central University, Jhongli, Taiwan, 32001, Republic of China
| | - Fan Bai
- Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing, 100871, China
| | - Teuta Pilizota
- Centre for Synthetic and Systems Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Alexander Crum Brown Road, EH9 3FF, Edinburgh, UK.
| | - Chien-Jung Lo
- Department of Physics and Graduate Institute of Biophysics, National Central University, Jhongli, Taiwan, 32001, Republic of China.
| |
Collapse
|
28
|
Zahir T, Camacho R, Vitale R, Ruckebusch C, Hofkens J, Fauvart M, Michiels J. High-throughput time-resolved morphology screening in bacteria reveals phenotypic responses to antibiotics. Commun Biol 2019; 2:269. [PMID: 31341968 PMCID: PMC6650389 DOI: 10.1038/s42003-019-0480-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 05/21/2019] [Indexed: 11/09/2022] Open
Abstract
Image-based high-throughput screening strategies for quantifying morphological phenotypes have proven widely successful. Here we describe a combined experimental and multivariate image analysis approach for systematic large-scale phenotyping of morphological dynamics in bacteria. Using off-the-shelf components and software, we established a workflow for high-throughput time-resolved microscopy. We then screened the single-gene deletion collection of Escherichia coli for antibiotic-induced morphological changes. Using single-cell quantitative descriptors and supervised classification methods, we measured how different cell morphologies developed over time for all strains in response to the β-lactam antibiotic cefsulodin. 191 strains exhibit significant variations under antibiotic treatment. Phenotypic clustering provided insights into processes that alter the antibiotic response. Mutants with stable bulges show delayed lysis, contributing to antibiotic tolerance. Lipopolysaccharides play a crucial role in bulge stability. This study demonstrates how multiparametric phenotyping by high-throughput time-resolved imaging and computer-aided cell classification can be used for comprehensively studying dynamic morphological transitions in bacteria.
Collapse
Affiliation(s)
- Taiyeb Zahir
- Centre of Microbial and Plant Genetics, KU Leuven—University of Leuven, Leuven, 3001 Belgium
- VIB-KU Leuven Center of Microbiology, Leuven, 3001 Belgium
| | - Rafael Camacho
- Department of Chemistry, KU Leuven—University of Leuven, Leuven, 3001 Belgium
| | - Raffaele Vitale
- Department of Chemistry, KU Leuven—University of Leuven, Leuven, 3001 Belgium
- LASIR CNRS, Université de Lille, Lille, F-59000 France
| | | | - Johan Hofkens
- Department of Chemistry, KU Leuven—University of Leuven, Leuven, 3001 Belgium
| | - Maarten Fauvart
- Centre of Microbial and Plant Genetics, KU Leuven—University of Leuven, Leuven, 3001 Belgium
- VIB-KU Leuven Center of Microbiology, Leuven, 3001 Belgium
- imec, Leuven, 3001 Belgium
| | - Jan Michiels
- Centre of Microbial and Plant Genetics, KU Leuven—University of Leuven, Leuven, 3001 Belgium
- VIB-KU Leuven Center of Microbiology, Leuven, 3001 Belgium
| |
Collapse
|
29
|
Eriksson EK, Edwards K, Grad P, Gedda L, Agmo Hernández V. Osmoprotective effect of ubiquinone in lipid vesicles modelling the E. coli plasma membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:1388-1396. [DOI: 10.1016/j.bbamem.2019.04.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 12/20/2018] [Accepted: 01/06/2019] [Indexed: 01/21/2023]
|
30
|
Dorey AL, Giovannercole F, Guerreiro D, Marinho C. Microbial stress meeting: From systems to molecules and back. N Biotechnol 2019; 49:66-70. [PMID: 30196137 DOI: 10.1016/j.nbt.2018.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/03/2018] [Accepted: 09/04/2018] [Indexed: 11/16/2022]
Abstract
The 4th Microbial Stress Meeting: from Systems to Moleculesand Back was held in April 2018 in Kinsale, Ireland. The meeting covered five main topics: 1. Stress at the systems and structural level; 2. Responses to osmotic and acid stress; 3. Stress responses in single cells; 4. Stress in host-pathogen interactions; and 5. Biotechnological optimisation of microorganisms through engineering and evolution, over three days. Almost 130 delegates, from 24 countries and both the industrial and academic sectors, attended the meeting, presenting 9 lectures, 28 short talks and 52 posters. The meeting showcased the diverse and rapid advancements in microbial stress research, from the single cell level to mixed populations. In this report, a summary of the highlights from the meeting is presented.
Collapse
Affiliation(s)
- Amber L Dorey
- Bacterial Stress Response Group, Department of Microbiology, National University of Ireland, Galway, Ireland.
| | - Fabio Giovannercole
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Latina, Italy
| | - Duarte Guerreiro
- Bacterial Stress Response Group, Department of Microbiology, National University of Ireland, Galway, Ireland
| | - Catarina Marinho
- Bacterial Stress Response Group, Department of Microbiology, National University of Ireland, Galway, Ireland; University of Burgundy, UMR 1347 Agroecoecology, INRA, Dijon, France
| |
Collapse
|
31
|
Ali MZ, Huang KC, Wingreen NS, Mukhopadhyay R. Cell geometry and leaflet bilayer asymmetry regulate domain formation in plasma membranes. Phys Rev E 2019; 99:012401. [PMID: 30780246 PMCID: PMC6553634 DOI: 10.1103/physreve.99.012401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Indexed: 11/07/2022]
Abstract
We model how pattern formation in a multicomponent lipid bilayer pinned to an elastic substrate is governed by the interplay between lipid phase separation and the tendency of domains of high intrinsic curvature lipids to deform the membrane away from a stiff substrate such as the cell wall. The emergent patterns, which include compact and striped lipid microdomains, are anticorrelated across the two leaflets and depend on leaflet asymmetry, the ability of lipids to flip between leaflets, and the global geometry. We characterize analytically the dependence of stripe width on lipid parameters, and consider the implications of interleaflet patterning for curvature-dependent lipid localization.
Collapse
Affiliation(s)
- Md Zulfikar Ali
- Department of Physics, Clark University, Worcester, MA 01610
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA 94305
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305
- Chan Zuckerberg Biohub, San Francisco, CA 943158
| | - Ned S. Wingreen
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540
| | | |
Collapse
|
32
|
Ma W, Wang J, Li Y, Wang X. Cysteine synthase A overexpression in Corynebacterium glutamicum enhances l-isoleucine production. Biotechnol Appl Biochem 2018; 66:74-81. [PMID: 30311712 DOI: 10.1002/bab.1698] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 10/01/2018] [Indexed: 01/12/2023]
Abstract
Cysteine synthase A (CysK) catalyzes the last reaction of l-cysteine synthesis in bacteria, but its moonlighting functions have been revealed recently. In this study, CysK was overexpressed in Corynebacterium glutamicum IWJ001, an l-isoleucine producer. Compared with the control IWJ001/pDXW-8, IWJ001/pDXW-8-cysK cells grew fast during log phase, and produced 26.5% more l-isoleucine in flask fermentation and 23.5% more l-isoleucine in fed-batch fermentation. The key genes aspC, lysC, hom, thrB, ilvA, and ilvBN involved in l-isoleucine biosynthesis were all upregulated in IWJ001/pDXW-8-cysK, compared with IWJ001/pDXW-8. In addition, IWJ001/pDXW-8-cysK cells were longer and thicker than IWJ001/pDXW-8 cells. Compared with IWJ001/pDXW-8, the membrane permeability increased 15.8% and biofilm formation ability decreased 71.3% for IWJ001/pDXW-8-cysK cells. The results demonstrate that CysK overexpression in C. glutamicum is a good approach to enhance l-isoleucine production.
Collapse
Affiliation(s)
- Wenjian Ma
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, People's Republic of China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, People's Republic of China
| | - Jianli Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, People's Republic of China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, People's Republic of China
| | - Ye Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, People's Republic of China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, People's Republic of China
| | - Xiaoyuan Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, People's Republic of China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, People's Republic of China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, People's Republic of China
| |
Collapse
|
33
|
Watson C, Hush P, Williams J, Dawson A, Ojkic N, Titmuss S, Waclaw B. Reduced adhesion between cells and substrate confers selective advantage in bacterial colonies
(a). ACTA ACUST UNITED AC 2018. [DOI: 10.1209/0295-5075/123/68001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
34
|
Wetzler DE, Fuchs Wightman F, Bucci HA, Rinaldi J, Caramelo JJ, Iusem ND, Ricardi MM. Conformational plasticity of the intrinsically disordered protein ASR1 modulates its function as a drought stress-responsive gene. PLoS One 2018; 13:e0202808. [PMID: 30138481 PMCID: PMC6107238 DOI: 10.1371/journal.pone.0202808] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 08/09/2018] [Indexed: 11/18/2022] Open
Abstract
Plants in arid zones are constantly exposed to drought stress. The ASR protein family (Abscisic, Stress, Ripening) -a subgroup of the late embryogenesis abundant superfamily- is involved in the water stress response and adaptation to dry environments. Tomato ASR1, as well as other members of this family, is an intrinsically disordered protein (IDP) that functions as a transcription factor and a chaperone. Here we employed different biophysical techniques to perform a deep in vitro characterization of ASR1 as an IDP and showed how both environmental factors and in vivo targets modulate its folding. We report that ASR1 adopts different conformations such as α-helix or polyproline type II in response to environmental changes. Low temperatures and low pH promote the polyproline type II conformation (PII). While NaCl increases PII content and slightly destabilizes α-helix conformation, PEG and glycerol have an important stabilizing effect of α-helix conformation. The binding of Zn2+in the low micromolar range promotes α-helix folding, while extra Zn2+ results in homo-dimerization. The ASR1-DNA binding is sequence specific and dependent on Zn2+. ASR1 chaperone activity does not change upon the structure induction triggered by the addition of Zn2+. Furthermore, trehalose, which has no effect on the ASR1 structure by itself, showed a synergistic effect on the ASR1-driven heat shock protection towards the reporter enzyme citrate synthase (CS). These observations prompted the development of a FRET reporter to sense ASR1 folding in vivo. Its performance was confirmed in Escherichia coli under saline and osmotic stress conditions, representing a promising probe to be used in plant cells. Overall, this work supports the notion that ASR1 plasticity is a key feature that facilitates its response to drought stress and its interaction with specific targets.
Collapse
Affiliation(s)
- Diana E. Wetzler
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
- * E-mail: (DW); (MR)
| | - Federico Fuchs Wightman
- Departamento de Fisiología y Biología Molecular y Celular (FBMC), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Hernan A. Bucci
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Jimena Rinaldi
- Fundación Instituto Leloir, Buenos Aires, Argentina e Instituto de investigaciones Bioquímicas de Buenos Aires (IIBBA- CONICET), Buenos Aires, Argentina
| | - Julio J. Caramelo
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Fundación Instituto Leloir, Buenos Aires, Argentina e Instituto de investigaciones Bioquímicas de Buenos Aires (IIBBA- CONICET), Buenos Aires, Argentina
| | - Norberto D. Iusem
- Departamento de Fisiología y Biología Molecular y Celular (FBMC), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Martiniano M. Ricardi
- Departamento de Fisiología y Biología Molecular y Celular (FBMC), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
- * E-mail: (DW); (MR)
| |
Collapse
|
35
|
Recent Evidence on Bioactive Glass Antimicrobial and Antibiofilm Activity: A Mini-Review. MATERIALS 2018; 11:ma11020326. [PMID: 29495292 PMCID: PMC5849023 DOI: 10.3390/ma11020326] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 02/14/2018] [Accepted: 02/17/2018] [Indexed: 12/19/2022]
Abstract
Bone defects caused by trauma or pathological events are major clinical and socioeconomic burdens. Thus, the efforts of regenerative medicine have been focused on the development of non-biodegradable materials resembling bone features. Consequently, the use of bioactive glass as a promising alternative to inert graft materials has been proposed. Bioactive glass is a synthetic silica-based material with excellent mechanical properties able to bond to the host bone tissue. Indeed, when immersed in physiological fluids, bioactive glass reacts, developing an apatite layer on the granule’s surface, playing a key role in the osteogenesis process. Moreover, the contact of bioactive glass with biological fluids results in the increase of osmotic pressure and pH due to the leaching of ions from granules’ surface, thus making the surrounding environment hostile to microbial growth. The bioactive glass antimicrobial activity is effective against a wide selection of aerobic and anaerobic bacteria, either in planktonic or sessile forms. Furthermore, bioglass is able to reduce pathogens’ biofilm production. For the aforementioned reasons, the use of bioactive glass might be a promising solution for the reconstruction of bone defects, as well as for the treatment and eradication of bone infections, characterized by bone necrosis and destruction of the bone structure.
Collapse
|
36
|
Quantitative Image Restoration in Bright Field Optical Microscopy. Biophys J 2017; 113:1916-1919. [PMID: 28988026 DOI: 10.1016/j.bpj.2017.09.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 08/18/2017] [Accepted: 09/05/2017] [Indexed: 11/20/2022] Open
Abstract
Bright field (BF) optical microscopy is regarded as a poor method to observe unstained biological samples due to intrinsic low image contrast. We introduce quantitative image restoration in bright field (QRBF), a digital image processing method that restores out-of-focus BF images of unstained cells. Our procedure is based on deconvolution, using a point spread function modeled from theory. By comparing with reference images of bacteria observed in fluorescence, we show that QRBF faithfully recovers shape and enables quantify size of individual cells, even from a single input image. We applied QRBF in a high-throughput image cytometer to assess shape changes in Escherichia coli during hyperosmotic shock, finding size heterogeneity. We demonstrate that QRBF is also applicable to eukaryotic cells (yeast). Altogether, digital restoration emerges as a straightforward alternative to methods designed to generate contrast in BF imaging for quantitative analysis.
Collapse
|
37
|
Fluorescent D-amino-acids reveal bi-cellular cell wall modifications important for Bdellovibrio bacteriovorus predation. Nat Microbiol 2017; 2:1648-1657. [PMID: 28974693 PMCID: PMC5705579 DOI: 10.1038/s41564-017-0029-y] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 08/11/2017] [Indexed: 01/05/2023]
Abstract
Modification of essential bacterial peptidoglycan (PG) containing cell
walls can lead to antibiotic resistance, for example β-lactam resistance
by L,D-transpeptidase activities. Predatory Bdellovibrio
bacteriovorus are naturally antibacterial and combat infections by
traversing, modifying and finally destroying walls of Gram-negative prey
bacteria, modifying their own PG as they grow inside prey. Historically, these
multi-enzymatic processes on two similar PG walls have proved challenging to
elucidate. Here, with a PG labelling approach utilizing timed pulses of multiple
fluorescent D-amino acids (FDAAs), we illuminate dynamic changes that predator
and prey walls go through during the different phases of bacteria:bacteria
invasion. We show formation of a reinforced circular port-hole in the prey wall;
L,D-transpeptidaseBd mediated D-amino acid modifications
strengthening prey PG during Bdellovibrio invasion and a zonal
mode of predator-elongation. This process is followed by unconventional,
multi-point and synchronous septation of the intracellular
Bdellovibrio, accommodating odd- and even-numbered progeny
formation by non-binary division.
Collapse
|
38
|
Even C, Marlière C, Ghigo JM, Allain JM, Marcellan A, Raspaud E. Recent advances in studying single bacteria and biofilm mechanics. Adv Colloid Interface Sci 2017; 247:573-588. [PMID: 28754382 DOI: 10.1016/j.cis.2017.07.026] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/18/2017] [Accepted: 07/18/2017] [Indexed: 12/15/2022]
Abstract
Bacterial biofilms correspond to surface-associated bacterial communities embedded in hydrogel-like matrix, in which high cell density, reduced diffusion and physico-chemical heterogeneity play a protective role and induce novel behaviors. In this review, we present recent advances on the understanding of how bacterial mechanical properties, from single cell to high-cell density community, determine biofilm tri-dimensional growth and eventual dispersion and we attempt to draw a parallel between these properties and the mechanical properties of other well-studied hydrogels and living systems.
Collapse
|
39
|
Abstract
Cellular mechanical properties play an integral role in bacterial survival and adaptation. Historically, the bacterial cell wall and, in particular, the layer of polymeric material called the peptidoglycan were the elements to which cell mechanics could be primarily attributed. Disrupting the biochemical machinery that assembles the peptidoglycan (e.g., using the β-lactam family of antibiotics) alters the structure of this material, leads to mechanical defects, and results in cell lysis. Decades after the discovery of peptidoglycan-synthesizing enzymes, the mechanisms that underlie their positioning and regulation are still not entirely understood. In addition, recent evidence suggests a diverse group of other biochemical elements influence bacterial cell mechanics, may be regulated by new cellular mechanisms, and may be triggered in different environmental contexts to enable cell adaptation and survival. This review summarizes the contributions that different biomolecular components of the cell wall (e.g., lipopolysaccharides, wall and lipoteichoic acids, lipid bilayers, peptidoglycan, and proteins) make to Gram-negative and Gram-positive bacterial cell mechanics. We discuss the contribution of individual proteins and macromolecular complexes in cell mechanics and the tools that make it possible to quantitatively decipher the biochemical machinery that contributes to bacterial cell mechanics. Advances in this area may provide insight into new biology and influence the development of antibacterial chemotherapies.
Collapse
Affiliation(s)
- George K Auer
- Department of Biomedical Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Douglas B Weibel
- Department of Biomedical Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States.,Department of Biochemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States.,Department of Chemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| |
Collapse
|
40
|
General calibration of microbial growth in microplate readers. Sci Rep 2016; 6:38828. [PMID: 27958314 PMCID: PMC5153849 DOI: 10.1038/srep38828] [Citation(s) in RCA: 172] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 11/15/2016] [Indexed: 11/15/2022] Open
Abstract
Optical density (OD) measurements of microbial growth are one of the most common techniques used in microbiology, with applications ranging from studies of antibiotic efficacy to investigations of growth under different nutritional or stress environments, to characterization of different mutant strains, including those harbouring synthetic circuits. OD measurements are performed under the assumption that the OD value obtained is proportional to the cell number, i.e. the concentration of the sample. However, the assumption holds true in a limited range of conditions, and calibration techniques that determine that range are currently missing. Here we present a set of calibration procedures and considerations that are necessary to successfully estimate the cell concentration from OD measurements.
Collapse
|
41
|
Mortimer M, Petersen EJ, Buchholz BA, Holden PA. Separation of Bacteria, Protozoa and Carbon Nanotubes by Density Gradient Centrifugation. NANOMATERIALS 2016; 6. [PMID: 27917301 PMCID: PMC5132190 DOI: 10.3390/nano6100181] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Sustainable production and use of carbon nanotube (CNT)-enabled materials require efficient assessment of CNT environmental hazards, including the potential for CNT bioaccumulation and biomagnification in environmental receptors. Microbes, as abundant organisms responsible for nutrient cycling in soil and water, are important ecological receptors for studying the effects of CNTs. Quantification of CNT association with microbial cells requires efficient separation of CNT-associated cells from individually dispersed CNTs and CNT agglomerates. Here, we designed, optimized, and demonstrated procedures for separating bacteria (Pseudomonas aeruginosa) from unbound multiwall carbon nanotubes (MWCNTs) and MWCNT agglomerates using sucrose density gradient centrifugation. We demonstrate separation of protozoa (Tetrahymena thermophila) from MWCNTs, bacterial agglomerates, and protozoan fecal pellets by centrifugation in an iodixanol solution. The presence of MWCNTs in the density gradients after centrifugation was determined by quantification of 14C-labeled MWCNTs; the recovery of microbes from the density gradient media was confirmed by optical microscopy. Protozoan intracellular contents of MWCNTs and of bacteria were also unaffected by the designed separation process. The optimized methods contribute to improved efficiency and accuracy in quantifying MWCNT association with bacteria and MWCNT accumulation in protozoan cells, thus supporting improved assessment of CNT bioaccumulation.
Collapse
Affiliation(s)
- Monika Mortimer
- Bren School of Environmental Science and Management, Earth Research Institute and University of California Center for the Environmental Implications of Nanotechnology (UC CEIN), University of California, Santa Barbara, CA 93106, USA;
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia
| | - Elijah J. Petersen
- Biosystems and Biomaterials Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA;
| | - Bruce A. Buchholz
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA;
| | - Patricia A. Holden
- Bren School of Environmental Science and Management, Earth Research Institute and University of California Center for the Environmental Implications of Nanotechnology (UC CEIN), University of California, Santa Barbara, CA 93106, USA;
- Correspondence: ; Tel.: +1-805-893-3195
| |
Collapse
|
42
|
Dynamics of Escherichia coli's passive response to a sudden decrease in external osmolarity. Proc Natl Acad Sci U S A 2016; 113:E5838-E5846. [PMID: 27647888 DOI: 10.1073/pnas.1522185113] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
For most cells, a sudden decrease in external osmolarity results in fast water influx that can burst the cell. To survive, cells rely on the passive response of mechanosensitive channels, which open under increased membrane tension and allow the release of cytoplasmic solutes and water. Although the gating and the molecular structure of mechanosensitive channels found in Escherichia coli have been extensively studied, the overall dynamics of the whole cellular response remain poorly understood. Here, we characterize E. coli's passive response to a sudden hypoosmotic shock (downshock) on a single-cell level. We show that initial fast volume expansion is followed by a slow volume recovery that can end below the initial value. Similar response patterns were observed at downshocks of a wide range of magnitudes. Although wild-type cells adapted to osmotic downshocks and resumed growing, cells of a double-mutant ([Formula: see text]) strain expanded, but failed to fully recover, often lysing or not resuming growth at high osmotic downshocks. We propose a theoretical model to explain our observations by simulating mechanosensitive channels opening, and subsequent solute efflux and water flux. The model illustrates how solute efflux, driven by mechanical pressure and solute chemical potential, competes with water influx to reduce cellular osmotic pressure and allow volume recovery. Our work highlights the vital role of mechanosensation in bacterial survival.
Collapse
|
43
|
Métris A, George SM, Ropers D. Piecewise linear approximations to model the dynamics of adaptation to osmotic stress by food-borne pathogens. Int J Food Microbiol 2016; 240:63-74. [PMID: 27377009 DOI: 10.1016/j.ijfoodmicro.2016.06.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 06/09/2016] [Accepted: 06/19/2016] [Indexed: 01/08/2023]
Abstract
Addition of salt to food is one of the most ancient and most common methods of food preservation. However, little is known of how bacterial cells adapt to such conditions. We propose to use piecewise linear approximations to model the regulatory adaptation of Escherichiacoli to osmotic stress. We apply the method to eight selected genes representing the functions known to be at play during osmotic adaptation. The network is centred on the general stress response factor, sigma S, and also includes a module representing the catabolic repressor CRP-cAMP. Glutamate, potassium and supercoiling are combined to represent the intracellular regulatory signal during osmotic stress induced by salt. The output is a module where growth is represented by the concentration of stable RNAs and the transcription of the osmotic gene osmY. The time course of gene expression of transport of osmoprotectant represented by the symporter proP and of the osmY is successfully reproduced by the network. The behaviour of the rpoS mutant predicted by the model is in agreement with experimental data. We discuss the application of the model to food-borne pathogens such as Salmonella; although the genes considered have orthologs, it seems that supercoiling is not regulated in the same way. The model is limited to a few selected genes, but the regulatory interactions are numerous and span different time scales. In addition, they seem to be condition specific: the links that are important during the transition from exponential to stationary phase are not all needed during osmotic stress. This model is one of the first steps towards modelling adaptation to stress in food safety and has scope to be extended to other genes and pathways, other stresses relevant to the food industry, and food-borne pathogens. The method offers a good compromise between systems of ordinary differential equations, which would be unmanageable because of the size of the system and for which insufficient data are available, and the more abstract Boolean methods.
Collapse
Affiliation(s)
- Aline Métris
- Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK.
| | - Susie M George
- Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK.
| | - Delphine Ropers
- Inria Grenoble - Rhône-Alpes Research Center, Saint Ismier, France.
| |
Collapse
|
44
|
Choi H, Chakraborty S, Liu R, Gellman SH, Weisshaar JC. Single-Cell, Time-Resolved Antimicrobial Effects of a Highly Cationic, Random Nylon-3 Copolymer on Live Escherichia coli. ACS Chem Biol 2016; 11:113-20. [PMID: 26493221 DOI: 10.1021/acschembio.5b00547] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Synthetic random copolymers based on the nylon-3 (β-peptide) backbone show promise as inexpensive antimicrobial agents resistant to proteolysis. We present a time-resolved observational study of the attack of a particular copolymer MM63:CHx37 on single, live Escherichia coli cells. The composition and chain length of MM63:CHx37 (63% cationic subunits, 37% hydrophobic subunits, 35-subunit average length) were optimized to enhance antibacterial activity while minimizing lysis of human red blood cells. For E. coli cells that export GFP to the periplasm, we obtain alternating phase-contrast and green fluorescence images with a time resolution of 12 s over 60 min following initiation of copolymer flow. Within seconds, cells shrink and exhibit the same plasmolysis spaces that occur following abrupt external osmotic upshift. The osmoprotection machinery attempts to replenish cytoplasmic water, but recovery is interrupted by permeabilization of the cytoplasmic membrane (CM) to GFP. Evidently, the highly cationic copolymer and its counterions rapidly translocate across the outer membrane without permeabilizing it to GFP. The CM permeabilization event is spatially localized. Cells whose CM has been permeabilized never recover growth. The minimum inhibitory concentration (MIC) for cells lacking the osmolyte importer ProP is 4-fold smaller than for normal cells, suggesting that osmoprotection is an important survival strategy. In addition, at the time of CM permeabilization, we observe evidence of oxidative stress. The MIC under anaerobic conditions is at least 8-fold larger than under aerobic conditions, further implicating oxidative damage as an important bacteriostatic effect. Once the copolymer reaches the periplasm, multiple growth-halting mechanisms proceed in parallel.
Collapse
Affiliation(s)
- Heejun Choi
- Department of Chemistry and ‡Molecular Biophysics
Program, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Saswata Chakraborty
- Department of Chemistry and ‡Molecular Biophysics
Program, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Runhui Liu
- Department of Chemistry and ‡Molecular Biophysics
Program, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Samuel H. Gellman
- Department of Chemistry and ‡Molecular Biophysics
Program, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - James C. Weisshaar
- Department of Chemistry and ‡Molecular Biophysics
Program, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| |
Collapse
|
45
|
Schwarz-Linek J, Arlt J, Jepson A, Dawson A, Vissers T, Miroli D, Pilizota T, Martinez VA, Poon WC. Escherichia coli as a model active colloid: A practical introduction. Colloids Surf B Biointerfaces 2016; 137:2-16. [DOI: 10.1016/j.colsurfb.2015.07.048] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 07/17/2015] [Accepted: 07/19/2015] [Indexed: 10/23/2022]
|
46
|
Eshghi A, Henderson J, Trent MS, Picardeau M. Leptospira interrogans lpxD Homologue Is Required for Thermal Acclimatization and Virulence. Infect Immun 2015; 83:4314-21. [PMID: 26283339 PMCID: PMC4598399 DOI: 10.1128/iai.00897-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 08/13/2015] [Indexed: 12/20/2022] Open
Abstract
Leptospirosis is an emerging disease with an annual occurrence of over 1 million human cases worldwide. Pathogenic Leptospira bacteria are maintained in zoonotic cycles involving a diverse array of mammals, with the capacity to survive outside the host in aquatic environments. Survival in the diverse environments encountered by Leptospira likely requires various adaptive mechanisms. Little is known about Leptospira outer membrane modification systems, which may contribute to the capacity of these bacteria to successfully inhabit and colonize diverse environments and animal hosts. Leptospira bacteria carry two genes annotated as UDP-3-O-[3-hydroxymyristoyl] glucosamine N-acyltransferase genes (la0512 and la4326 [lpxD1 and lpxD2]) that in other bacteria are involved in the early steps of biosynthesis of lipid A, the membrane lipid anchor of lipopolysaccharide. Inactivation of only one of these genes, la0512/lpxD1, imparted sensitivity to the host physiological temperature (37°C) and rendered the bacteria avirulent in an animal infection model. Polymyxin B sensitivity assays revealed compromised outer membrane integrity in the lpxD1 mutant at host physiological temperature, but structural analysis of lipid A in the mutant revealed only minor changes in the lipid A moiety compared to that found in the wild-type strain. In accordance with this, an in trans complementation restored the phenotypes to a level comparable to that of the wild-type strain. These results suggest that the gene annotated as lpxD1 in Leptospira interrogans plays an important role in temperature adaptation and virulence in the animal infection model.
Collapse
Affiliation(s)
- Azad Eshghi
- Institut Pasteur, Biology of Spirochetes Unit, Paris, France
| | - Jeremy Henderson
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
| | - M Stephen Trent
- Department of Infectious Disease, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | | |
Collapse
|
47
|
Taute H, Bester MJ, Neitz AWH, Gaspar ARM. Investigation into the mechanism of action of the antimicrobial peptides Os and Os-C derived from a tick defensin. Peptides 2015. [PMID: 26215047 DOI: 10.1016/j.peptides.2015.07.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Os and Os-C are two novel antimicrobial peptides, derived from a tick defensin, which have been shown to have a larger range of antimicrobial activity than the parent peptide, OsDef2. The aim of this study was to determine whether the peptides Os and Os-C are mainly membrane acting, or if these peptides have possible additional intracellular targets in Escherichia coli and Bacillus subtilis. Transmission electron microscopy revealed that both peptides adversely affected intracellular structure of both bacteria causing different degrees of granulation of the intracellular contents. At the minimum bactericidal concentrations, permeabilization as determined with the SYTOX green assay seemed not to be the principle mode of killing when compared to melittin. However, fluorescent triple staining indicated that the peptides caused permeabilization of stationary phase bacteria and TEM indicated membrane effects. Studies using fluorescently labeled peptides revealed that the membrane penetrating activity of Os and Os-C was similar to buforin II. Os-C was found to associate with the septa of B. subtilis. Plasmid binding studies showed that Os and Os-C binds E. coli plasmid DNA at a similar charge ratio as melittin. These studies suggest membrane activity for Os and Os-C with possible intracellular targets such as DNA. The differences in permeabilization at lower concentrations and binding to DNA between Os and Os-C, suggest that the two peptides have dissimilar modes of action.
Collapse
Affiliation(s)
- Helena Taute
- Department of Anatomy, Faculty of Health Sciences, University of Pretoria, 0002, South Africa.
| | - Megan J Bester
- Department of Anatomy, Faculty of Health Sciences, University of Pretoria, 0002, South Africa
| | - Albert W H Neitz
- Department of Biochemistry, Faculty of Natural Sciences, University of Pretoria, 0002, South Africa
| | - Anabella R M Gaspar
- Department of Biochemistry, Faculty of Natural Sciences, University of Pretoria, 0002, South Africa
| |
Collapse
|
48
|
Drago L, De Vecchi E, Bortolin M, Toscano M, Mattina R, Romanò CL. Antimicrobial activity and resistance selection of different bioglass S53P4 formulations against multidrug resistant strains. Future Microbiol 2015; 10:1293-9. [PMID: 26228640 DOI: 10.2217/fmb.15.57] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AIMS This study aimed to evaluate the antimicrobial activity of two different formulations of bioglass BAG-S53P4 against multiresistant microorganisms involved in bone infections, and the capability of bioglass to select for resistance. METHODS Antibacterial activity was evaluated by means of killing curves. The ability to select for resistant bacteria was evaluated by subculturing microorganisms in serial dilutions of bioglass. Scanning electron microscope acquisitions were conducted to evaluate bioglass-induced morphology changes. RESULTS BAG-S53P4 formulations display a high antimicrobial activity and do not seem to select for resistance. Scanning electron microscopy analysis showed cell shrinkage and membrane damage after exposure to bioglass. CONCLUSIONS BAG-S53P4 has a significant potential as bone substitute for the treatment of infections caused by multiresistant microorganisms.
Collapse
Affiliation(s)
- Lorenzo Drago
- Laboratory of Clinical Chemistry & Microbiology, IRCCS Galeazzi Orthopaedic Institute, via R Galeazzi 4, 20161 Milan, Italy.,Laboratory of Technical Sciences for Laboratory Medicine, Department of Biomedical Science for Health, University of Milan, via L Mangiagalli 31, 20133 Milan, Italy
| | - Elena De Vecchi
- Laboratory of Clinical Chemistry & Microbiology, IRCCS Galeazzi Orthopaedic Institute, via R Galeazzi 4, 20161 Milan, Italy
| | - Monica Bortolin
- Laboratory of Clinical Chemistry & Microbiology, IRCCS Galeazzi Orthopaedic Institute, via R Galeazzi 4, 20161 Milan, Italy
| | - Marco Toscano
- Laboratory of Clinical Chemistry & Microbiology, IRCCS Galeazzi Orthopaedic Institute, via R Galeazzi 4, 20161 Milan, Italy
| | - Roberto Mattina
- Department of Public Health, Microbiology & Virology, University of Milan, via C Pascal 36, 20133 Milan, Italy
| | - Carlo Luca Romanò
- Centre for Reconstructive Surgery & Bone Infections, IRCCS Galeazzi Orthopaedic Institute, via R Galeazzi 4, 20161 Milan, Italy
| |
Collapse
|
49
|
Pilizota T, Shaevitz JW. Origins of Escherichia coli growth rate and cell shape changes at high external osmolality. Biophys J 2015; 107:1962-1969. [PMID: 25418177 DOI: 10.1016/j.bpj.2014.08.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 07/23/2014] [Accepted: 08/06/2014] [Indexed: 01/12/2023] Open
Abstract
In Escherichia coli, a sudden increase in external concentration causes a pressure drop across the cell envelope, followed by an active recovery. After recovery, and if the external osmolality remains high, cells have been shown to grow more slowly, smaller, and at reduced turgor pressure. Despite the fact that the active recovery is a key stress response, the nature of these changes and how they relate to each other is not understood. Here, we use fluorescence imaging of single cells during hyperosmotic shocks, combined with custom made microfluidic devices, to show that cells fully recover their volume to the initial, preshock value and continue to grow at a slower rate immediately after the recovery. We show that the cell envelope material properties do not change after hyperosmotic shock, and that cell shape recovers along with cell volume. Taken together, these observations indicate that the turgor pressure recovers to its initial value so that reduced turgor is not responsible for the reduced growth rate observed immediately after recovery. To determine the point at which the reduction in cell size and turgor pressure occurs after shock, we measured the volume of E. coli cells at different stages of growth in bulk cultures. We show that cell volume reaches the same maximal level irrespective of the osmolality of the media. Based on these measurements, we propose that turgor pressure is used as a feedback variable for osmoregulatory pumps instead of being directly responsible for the reduction in growth rates. Reestablishment of turgor to its initial value might ensure correct attachment of the inner membrane and cell wall needed for cell wall biosynthesis.
Collapse
Affiliation(s)
- Teuta Pilizota
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey; School of Biology and Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, United Kingdom.
| | - Joshua W Shaevitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey; Department of Physics, Princeton University, Princeton, New Jersey
| |
Collapse
|
50
|
Affiliation(s)
- Janet M Wood
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| |
Collapse
|