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Felipe-López A, Hansmeier N, Hensel M. Destruction of the brush border by Salmonella enterica sv. Typhimurium subverts resorption by polarized epithelial cells. Front Microbiol 2024; 15:1329798. [PMID: 38894970 PMCID: PMC11183102 DOI: 10.3389/fmicb.2024.1329798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Accepted: 05/06/2024] [Indexed: 06/21/2024] Open
Abstract
Salmonella enterica serovar Typhimurium is an invasive, facultative intracellular gastrointestinal pathogen that destroys the brush border of polarized epithelial cells (PEC). The brush border is critical for the functions of PEC because it resorbs nutrients from the intestinal lumen and builds a physical barrier to infecting pathogens. The manipuation of PEC during infection by Salmonella was investigated by live-cell imaging and ultrastructural analysed of the brush border. We demonstrate that the destruction of the brush border by Salmonella significantly reduces the resorption surface of PEC along with the abrogation of endocytosis at the apical side of PEC. Both these changes in the physiology of PEC were associated with the translocation of type III secretion system effector protein SopE. Additionally, the F-actin polymerization rate at the apical side of PEC was highly altered by SopE, indicating that reduced endocytosis observed in infected PEC is related to the manipulation of F-actin polymerization mediated by SopE and, to a lesser extent, by effectors SopE2 or SipA. We further observed that in the absence of SopE, Salmonella effaced microvilli and induced reticular F-actin by bacterial accumulation during prolonged infection periods. In contrast to strains translocating SopE, strains lacking SopE did not alter resorption by PEC. Finally, we observed that after engulfment of Salmonella, ezrin was lost from the apical side of PEC and found later in early endosomes containing Salmonella. Our observations suggest that the destruction of the brush border by Salmonella may contribute to the pathogenesis of diarrhea.
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Affiliation(s)
| | | | - Michael Hensel
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
- CellNanOs—Center of Cellular Nanoanalytics Osnabrück, Universität Osnabrück, Osnabrück, Germany
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Miller KK, Wang P, Grillet N. SUB-Immunogold-SEM reveals nanoscale distribution of submembranous epitopes. RESEARCH SQUARE 2024:rs.3.rs-3876898. [PMID: 38343799 PMCID: PMC10854333 DOI: 10.21203/rs.3.rs-3876898/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Electron microscopy paired with immunogold labeling is the most precise tool for protein localization. However, these methods are either cumbersome, resulting in small sample numbers and restricted quantification, or limited to identifying protein epitopes external to the membrane. Here, we introduce SUB-immunogold-SEM, a scanning electron microscopy technique that detects intracellular protein epitopes proximal to the membrane. We identified four critical sample preparation factors that contribute to the method's sensitivity and validate its efficacy through precise localization and high-powered quantification of cytoskeletal and transmembrane proteins. We evaluated the capabilities of SUB-immunogold-SEM on cells with highly differentiated apical surfaces: (i) auditory hair cells, revealing the presence of nanoscale Myosin rings at the tip of stereocilia; and (ii) respiratory multiciliate cells, mapping the distribution of the SARS-CoV-2 receptor ACE2 along the motile cilia. SUB-immunogold-SEM provides a novel solution for nanoscale protein localization at the exposed surface of any cell.
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Affiliation(s)
- Katharine K. Miller
- Department of Otolaryngology-Head & Neck Surgery, School of Medicine, 240 Pasteur Drive, Stanford University, Stanford, CA 94305, USA
| | - Pei Wang
- Department of Otolaryngology-Head & Neck Surgery, School of Medicine, 240 Pasteur Drive, Stanford University, Stanford, CA 94305, USA
| | - Nicolas Grillet
- Department of Otolaryngology-Head & Neck Surgery, School of Medicine, 240 Pasteur Drive, Stanford University, Stanford, CA 94305, USA
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3
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Mentor S, Cummings F, Fisher D. Preparation of biological monolayers for producing high-resolution scanning electron micrographs. PLoS One 2022; 17:e0266943. [PMID: 35802747 PMCID: PMC9269934 DOI: 10.1371/journal.pone.0266943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 03/26/2022] [Indexed: 11/18/2022] Open
Abstract
Scanning electron microscopy (SEM) provides a technical platform for nanoscopic mapping of biological structures. Correct preparation of SEM samples can provide an unprecedented understanding of the nexus between cellular morphology and topography. This comparative study critically examines two coating methods for preparing biological samples for scanning electron microscopy, while also providing novel advice on how to prepare in vitro epithelial or endothelial samples for high-resolution scanning-electron microscopy (HR-SEM). Two obstacles often confront the biologist when investigating cellular structures grown under tissue culture conditions, namely., how to prepare and present the biological samples to the HR-SEM microscope without affecting topographical membrane and cellular structural alterations. Firstly, our use of the Millicell cellulose inserts on which to grow our cellular samples in preparation for HR-SEM is both novel and advantageous to comparing the permeability function of cells to their morphological function. Secondly, biological material is often non-conducting, thermally sensitive and fragile and, therefore, needs to be fixed correctly and coated with thin conducting metal to ensure high-resolution detail of samples. Immortalized mouse brain endothelial cells (bEnd5) was used as a basis for describing the preferences in the use of the protocol. We compare two biological sample coating modalities for the visualizing and analysis of texturized, topographical, membranous ultrastructures of brain endothelial cell (BEC) confluent monolayers, namely, carbon and gold:palladium (Au:Pd) sputter coating in preparation for HR-SEM. BEC monolayers sputter-coated with these two modalities produced three-dimensional micrographs which have distinctly different topographical detail from which the nanostructural cellular data can be examined. The two coating methods display differences in the amount of nanoscopic detail that could be resolved in the nanosized membrane cytoarchitecture of BEC monolayers. The micrographical data clearly showed that Au:Pd sputter-coated samples generate descript imagery, providing useful information for profiling membrane nanostructures compared to carbon-coated samples. The recommendations regarding the contrast in two modalities would provide the necessary guidance to biological microscopists in preparing tissue culture samples for HR-SEM.
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Affiliation(s)
- Shireen Mentor
- Department of Medical Biosciences, Faculty of Natural Sciences, University of The Western Cape, Cape Town, South Africa
| | - Franscious Cummings
- Department of Physics and Astronomy, Electron Microscopy Unit, University of The Western Cape, Cape Town, South Africa
| | - David Fisher
- Department of Medical Biosciences, Faculty of Natural Sciences, University of The Western Cape, Cape Town, South Africa
- School of Health Professions, University of Missouri, Columbia, Missouri, United States of America
- * E-mail:
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Canid herpesvirus 1 Preferentially Infects Polarized Madin-Darby Canine Kidney Cells from the Basolateral Surface. Viruses 2022; 14:v14061291. [PMID: 35746762 PMCID: PMC9230387 DOI: 10.3390/v14061291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/15/2022] [Accepted: 06/11/2022] [Indexed: 11/17/2022] Open
Abstract
Canid herpesvirus 1 (CHV-1) infects polarized canine epithelia. Herein, we present our initial work characterizing CHV-1 infection of Madin-Darby canine kidney (MDCK) cells that were polarized on trans-wells. We previously showed that infection of these cells in non-polarized cultures stimulated the formation of extensive lamellipodial membrane protrusions. Uninfected polarized MDCK cells already form extensive lamellipodial membrane protrusions on the apical surface in the absence of virus. Using scanning electron microscopy, we found that CHV-1 infection does not lead to a change in the form of the lamellipodial membrane protrusions on the apical surface of polarized MDCK cells. We found that CHV-1 was able to infect polarized cultures from either the apical or basolateral side; however, higher viral titers were produced upon infection of the basolateral side. Regardless of the side infected, titers of virus were higher in the apical compartment compared to the basal compartment; however, these differences were not statistically significant. In addition to cell-free virus that was recovered in the media, the highest amount of virus produced remained cell-associated over the course of the experiment. The efficiency of CHV-1 infection of the basolateral side of polarized epithelial cells is consistent with the pathobiology of this varicellovirus.
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Khare D, Chandwadkar P, Acharya C. Structural Analysis of Gliding Motility of a Bacteroidetes Bacterium by Correlative Light and Scanning Electron Microscopy (CLSEM). MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2022; 28:1-7. [PMID: 35105420 DOI: 10.1017/s1431927622000095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The members of the Bacteroidetes phylum move on surfaces by gliding motility in the absence of external motility appendages, leading to the formation of spreading colonies. Here, the structural features of the spreading colony were assessed in a uranium-tolerant Bacteroidetes bacterium, Chryseobacterium sp. strain PMSZPI, by using correlative light and scanning electron microscopy (CLSEM). We developed a simple and convenient workflow for CLSEM using a shuttle and find software module and a correlative sample holding slide designed to transport samples between the light/fluorescence microscope (LM/FM) and the scanning electron microscope (SEM) to image spreading colony edges. The datasets from the CLSEM studies allowed convenient examination of the colonial organization by LM/FM followed by ultrastructural analysis by SEM. The regions of interest (ROIs) of the spreading colony edges that were observed in LM/FM in the absence and presence of uranium could be re-identified in the SEM quickly without prolonged searching. Perfect correlation between LM and SEM could be achieved with minimum preparation steps. Subsequently, imaging of the correlated regions was done at higher resolution in SEM to obtain more comprehensive information. We further showed the association of uranium with the gliding PMSZPI cells by energy-dispersive X-ray spectroscopy (EDS) attached to SEM.
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Affiliation(s)
- Devanshi Khare
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai400085, India
- Homi Bhabha National Institute, Anushakti Nagar, Mumbai400094, India
| | - Pallavi Chandwadkar
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai400085, India
| | - Celin Acharya
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai400085, India
- Homi Bhabha National Institute, Anushakti Nagar, Mumbai400094, India
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Manfredini A, Malusà E, Costa C, Pallottino F, Mocali S, Pinzari F, Canfora L. Current Methods, Common Practices, and Perspectives in Tracking and Monitoring Bioinoculants in Soil. Front Microbiol 2021; 12:698491. [PMID: 34531836 PMCID: PMC8438429 DOI: 10.3389/fmicb.2021.698491] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/28/2021] [Indexed: 12/22/2022] Open
Abstract
Microorganisms promised to lead the bio-based revolution for a more sustainable agriculture. Beneficial microorganisms could be a valid alternative to the use of chemical fertilizers or pesticides. However, the increasing use of microbial inoculants is also raising several questions about their efficacy and their effects on the autochthonous soil microorganisms. There are two major issues on the application of bioinoculants to soil: (i) their detection in soil, and the analysis of their persistence and fate; (ii) the monitoring of the impact of the introduced bioinoculant on native soil microbial communities. This review explores the strategies and methods that can be applied to the detection of microbial inoculants and to soil monitoring. The discussion includes a comprehensive critical assessment of the available tools, based on morpho-phenological, molecular, and microscopic analyses. The prospects for future development of protocols for regulatory or commercial purposes are also discussed, underlining the need for a multi-method (polyphasic) approach to ensure the necessary level of discrimination required to track and monitor bioinoculants in soil.
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Affiliation(s)
- Andrea Manfredini
- Council for Agricultural Research and Economics, Research Centre for Agriculture and Environment, Rome, Italy
| | - Eligio Malusà
- National Research Institute of Horticulture, Skierniewice, Poland
- Council for Agricultural Research and Economics, Research Centre for Viticulture and Enology, Conegliano, Italy
| | - Corrado Costa
- Council for Agricultural Research and Analysis of the Agricultural Economy, Research Centre for Engineering and Agro-Food Processing, Monterotondo, Italy
| | - Federico Pallottino
- Council for Agricultural Research and Analysis of the Agricultural Economy, Research Centre for Engineering and Agro-Food Processing, Monterotondo, Italy
| | - Stefano Mocali
- Council for Agricultural Research and Economics, Research Centre for Agriculture and Environment, Rome, Italy
| | - Flavia Pinzari
- Institute for Biological Systems, Council of National Research of Italy (CNR), Rome, Italy
- Life Sciences Department, Natural History Museum, London, United Kingdom
| | - Loredana Canfora
- Council for Agricultural Research and Economics, Research Centre for Agriculture and Environment, Rome, Italy
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7
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Skaar EP. Imaging Infection Across Scales of Size: From Whole Animals to Single Molecules. Annu Rev Microbiol 2021; 75:407-426. [PMID: 34343016 DOI: 10.1146/annurev-micro-041521-121457] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Infectious diseases are a leading cause of global morbidity and mortality, and the threat of infectious diseases to human health is steadily increasing as new diseases emerge, existing diseases reemerge, and antimicrobial resistance expands. The application of imaging technology to the study of infection biology has the potential to uncover new factors that are critical to the outcome of host-pathogen interactions and to lead to innovations in diagnosis and treatment of infectious diseases. This article reviews current and future opportunities for the application of imaging to the study of infectious diseases, with a particular focus on the power of imaging objects across a broad range of sizes to expand the utility of these approaches. Expected final online publication date for the Annual Review of Microbiology, Volume 75 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Eric P Skaar
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA;
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Zhu C, Wang A, Chen L, Guo L, Ye J, Chen Q, Wang Q, Yao G, Xia Q, Cai T, Guo J, Yang Z, Sun Z, Xu Y, Lu G, Zhang Z, Cao J, Liu Y, Xu H. Measurement of expansion factor and distortion for expansion microscopy using isolated renal glomeruli as landmarks. JOURNAL OF BIOPHOTONICS 2021; 14:e202100001. [PMID: 33856738 DOI: 10.1002/jbio.202100001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 03/14/2021] [Accepted: 04/08/2021] [Indexed: 06/12/2023]
Abstract
Expansion microscopy has enabled super resolution imaging of biological samples. The accurate measurement of expansion factor and distortion typically requires locating and imaging the same region of interest in the sample before and after expansion, which is often time-consuming to achieve. Here we introduce a convenient method for relocation by utilizing isolated porcine glomeruli as landmarks during expansion. Following heat denaturation and proteinase K digestion protocols, the glomeruli exhibit expansion factor of 3.5 to 4 (only 7%-16% less expanded than the hydrogel), and 1% to 2% of relative distortion. Due to its appropriate size of 100 to 300 μm, the location of the glomerulus in the sample are visible to eyes, while its detailed shape only requires bright field microscopy. For expansion factors ranging from 3 to 10, the region in the vicinity of the glomerulus can be easily re-identified, and sometimes allows quantification of expansion factor and distortion under bright field without fluorescent labels.
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Affiliation(s)
- Chen Zhu
- Institute for Advanced Study, Soochow University, Suzhou, China
- School of Optoelectronic Science and Engineering, Soochow University, Suzhou, China
| | - Aidong Wang
- The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Lili Chen
- The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Liangsheng Guo
- The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Jiajia Ye
- Institute for Advanced Study, Soochow University, Suzhou, China
- School of Physical Science and Technology, Soochow University, Suzhou, China
| | - Qilin Chen
- Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Qi Wang
- Institute for Advanced Study, Soochow University, Suzhou, China
- School of Optoelectronic Science and Engineering, Soochow University, Suzhou, China
| | - Guojia Yao
- Institute for Advanced Study, Soochow University, Suzhou, China
- School of Physical Science and Technology, Soochow University, Suzhou, China
| | - Qin Xia
- Institute for Advanced Study, Soochow University, Suzhou, China
- School of Physical Science and Technology, Soochow University, Suzhou, China
| | - Tianyu Cai
- Institute for Advanced Study, Soochow University, Suzhou, China
- School of Physical Science and Technology, Soochow University, Suzhou, China
| | - Jiayun Guo
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, China
| | - Zhenyu Yang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, China
| | - Zhenglong Sun
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, China
| | - Yuwei Xu
- The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Guoyuan Lu
- The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Zexin Zhang
- Institute for Advanced Study, Soochow University, Suzhou, China
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, China
| | - Jingyuan Cao
- Department of Nephrology, Taizhou People's Hospital, the Fifth Affiliated Hospital of Nantong University, Taizhou, China
| | - Ying Liu
- Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China
| | - Huizhong Xu
- Institute for Advanced Study, Soochow University, Suzhou, China
- School of Physical Science and Technology, Soochow University, Suzhou, China
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Park AJ, Wright MA, Roach EJ, Khursigara CM. Imaging host-pathogen interactions using epithelial and bacterial cell infection models. J Cell Sci 2021; 134:134/5/jcs250647. [PMID: 33622798 DOI: 10.1242/jcs.250647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The age-old saying, seeing is believing, could not be truer when we think about the value of imaging interactions between epithelial cells and bacterial pathogens. Imaging and culturing techniques have vastly improved over the years, and the breadth and depth of these methods is ever increasing. These technical advances have benefited researchers greatly; however, due to the large number of potential model systems and microscopy techniques to choose from, it can be overwhelming to select the most appropriate tools for your research question. This Review discusses a variety of available epithelial culturing methods and quality control experiments that can be performed, and outlines various options commonly used to fluorescently label bacterial and mammalian cell components. Both light- and electron-microscopy techniques are reviewed, with descriptions of both technical aspects and common applications. Several examples of imaging bacterial pathogens and their interactions with epithelial cells are discussed to provide researchers with an idea of the types of biological questions that can be successfully answered by using microscopy.
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Affiliation(s)
- Amber J Park
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Madison A Wright
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Elyse J Roach
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada.,Molecular and Cellular Imaging Facility, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Cezar M Khursigara
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada .,Molecular and Cellular Imaging Facility, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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