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Ghaffar SA, Tahir H, Muhammad S, Shahid M, Naqqash T, Faisal M, Albekairi TH, Alshammari A, Albekairi NA, Manzoor I. Designing of a multi-epitopes based vaccine against Haemophilius parainfluenzae and its validation through integrated computational approaches. Front Immunol 2024; 15:1380732. [PMID: 38690283 PMCID: PMC11058264 DOI: 10.3389/fimmu.2024.1380732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 04/01/2024] [Indexed: 05/02/2024] Open
Abstract
Haemophilus parainfluenzae is a Gram-negative opportunist pathogen within the mucus of the nose and mouth without significant symptoms and has an ability to cause various infections ranging from ear, eye, and sinus to pneumonia. A concerning development is the increasing resistance of H. parainfluenzae to beta-lactam antibiotics, with the potential to cause dental infections or abscesses. The principal objective of this investigation is to utilize bioinformatics and immuno-informatic methodologies in the development of a candidate multi-epitope Vaccine. The investigation focuses on identifying potential epitopes for both B cells (B lymphocytes) and T cells (helper T lymphocytes and cytotoxic T lymphocytes) based on high non-toxic and non-allergenic characteristics. The selection process involves identifying human leukocyte antigen alleles demonstrating strong associations with recognized antigenic and overlapping epitopes. Notably, the chosen alleles aim to provide coverage for 90% of the global population. Multi-epitope constructs were designed by using suitable linker sequences. To enhance the immunological potential, an adjuvant sequence was incorporated using the EAAAK linker. The final vaccine construct, comprising 344 amino acids, was achieved after the addition of adjuvants and linkers. This multi-epitope Vaccine demonstrates notable antigenicity and possesses favorable physiochemical characteristics. The three-dimensional conformation underwent modeling and refinement, validated through in-silico methods. Additionally, a protein-protein molecular docking analysis was conducted to predict effective binding poses between the multi-epitope Vaccine and the Toll-like receptor 4 protein. The Molecular Dynamics (MD) investigation of the docked TLR4-vaccine complex demonstrated consistent stability over the simulation period, primarily attributed to electrostatic energy. The docked complex displayed minimal deformation and enhanced rigidity in the motion of residues during the dynamic simulation. Furthermore, codon translational optimization and computational cloning was performed to ensure the reliability and proper expression of the multi-Epitope Vaccine. It is crucial to emphasize that despite these computational validations, experimental research in the laboratory is imperative to demonstrate the immunogenicity and protective efficacy of the developed vaccine. This would involve practical assessments to ascertain the real-world effectiveness of the multi-epitope Vaccine.
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Affiliation(s)
- Sana Abdul Ghaffar
- Department of Bioinformatics and Biotechnology, Government College University, Faisalabad, Pakistan
| | - Haneen Tahir
- Department of Bioinformatics and Biotechnology, Government College University, Faisalabad, Pakistan
| | - Sher Muhammad
- Department of Bioinformatics and Biotechnology, Government College University, Faisalabad, Pakistan
| | - Muhammad Shahid
- Department of Bioinformatics and Biotechnology, Government College University, Faisalabad, Pakistan
| | - Tahir Naqqash
- Institute of Molecular Biology and Biotechnology, Bahauddin Zakariya University, Multan, Pakistan
| | | | - Thamer H. Albekairi
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Abdulrahman Alshammari
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Norah A. Albekairi
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Irfan Manzoor
- Department of Bioinformatics and Biotechnology, Government College University, Faisalabad, Pakistan
- Department of Biology, Indiana University, Bloomington, IN, United States
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Sarma A, Dhandapani G, Phukan H, Bhunia PK, De AK, Bhattacharya D, Jebasingh T, Madanan MG. Leptospiral cell wall hydrolase (LIC_10271) binding peptidoglycan, lipopolysaccharide, and laminin and the protein show LysM and M23 domains are co-existing in pathogenic species. Res Microbiol 2023; 174:104107. [PMID: 37517629 DOI: 10.1016/j.resmic.2023.104107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 07/07/2023] [Accepted: 07/21/2023] [Indexed: 08/01/2023]
Abstract
Leptospirosis, a global reemerging zoonosis caused by the spirochete Leptospira, has severe human and veterinary implications. Cell wall hydrolase (LIC_10271) with LytM (peptidase M23) and LysM domains are found to be associated with various pathogenic bacteria. These domains regulate effects on extracellular matrix and biofilm components, which promote cell wall remodeling and pathogen dissemination in the host. In this study, we present the cloning, expression, purification, and characterization of LIC_10271. To determine the localization of LIC_10271 within the inner membrane of Leptospira, Triton X-114 subcellular fractionation and immunoblot studies were performed. Furthermore, r-LIC_10271 binds with peptidoglycan, lipopolysaccharide, and laminin in a dose-dependent manner. Analysis of the signal peptide, M23, and LysM domains revealed conservation primarily within the P1 group of Leptospira, which encompasses the most pathogenic species. Moreover, the presence of native-LIC_10271 in the inner membrane and the distribution of M23 and LysM domains across pathogenic strains indicates their potential involvement in the interaction between the host and Leptospira.
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Affiliation(s)
- Abhijit Sarma
- Department of Biochemistry, ICMR - Regional Medical Research Centre, Port Blair 744103, Andaman and Nicobar Islands, India
| | - Gunasekaran Dhandapani
- Department of Biochemistry, ICMR - Regional Medical Research Centre, Port Blair 744103, Andaman and Nicobar Islands, India
| | - Homen Phukan
- Department of Biochemistry, ICMR - Regional Medical Research Centre, Port Blair 744103, Andaman and Nicobar Islands, India
| | - Prasun Kumar Bhunia
- Department of Plant Sciences, School of Biological Sciences, Madurai Kamraj University, Madurai, Tamil Nadu 625021, India
| | - Arun Kumar De
- Division of Animal Science, ICAR- Central Island Agricultural Research Institute, Port Blair, Andaman and Nicobar Islands 744101, India
| | - Debasis Bhattacharya
- Division of Animal Science, ICAR- Central Island Agricultural Research Institute, Port Blair, Andaman and Nicobar Islands 744101, India
| | - T Jebasingh
- Department of Plant Sciences, School of Biological Sciences, Madurai Kamraj University, Madurai, Tamil Nadu 625021, India
| | - Madathiparambil G Madanan
- Department of Biochemistry, ICMR - Regional Medical Research Centre, Port Blair 744103, Andaman and Nicobar Islands, India.
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Su YC, Kadari M, Straw ML, Janoušková M, Jonsson S, Thofte O, Jalalvand F, Matuschek E, Sandblad L, Végvári Á, Zubarev RA, Riesbeck K. Non-typeable Haemophilus influenzae major outer membrane protein P5 contributes to bacterial membrane stability, and affects the membrane protein composition crucial for interactions with the human host. Front Cell Infect Microbiol 2023; 13:1085908. [PMID: 37305414 PMCID: PMC10250671 DOI: 10.3389/fcimb.2023.1085908] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 04/10/2023] [Indexed: 06/13/2023] Open
Abstract
Non-typeable Haemophilus influenzae (NTHi) is a Gram-negative human pathogen that causes a wide range of airway diseases. NTHi has a plethora of mechanisms to colonize while evading the host immune system for the establishment of infection. We previously showed that the outer membrane protein P5 contributes to bacterial serum resistance by the recruitment of complement regulators. Here, we report a novel role of P5 in maintaining bacterial outer membrane (OM) integrity and protein composition important for NTHi-host interactions. In silico analysis revealed a peptidoglycan-binding motif at the periplasmic C-terminal domain (CTD) of P5. In a peptidoglycan-binding assay, the CTD of P5 (P5CTD) formed a complex with peptidoglycan. Protein profiling analysis revealed that deletion of CTD or the entire P5 changed the membrane protein composition of the strains NTHi 3655Δp5CTD and NTHi 3655Δp5, respectively. Relative abundance of several membrane-associated virulence factors that are crucial for adherence to the airway mucosa, and serum resistance were altered. This was also supported by similar attenuated pathogenic phenotypes observed in both NTHi 3655Δp5 CTD and NTHi 3655Δp5. We found (i) a decreased adherence to airway epithelial cells and fibronectin, (ii) increased complement-mediated killing, and (iii) increased sensitivity to the β-lactam antibiotics in both mutants compared to NTHi 3655 wild-type. These mutants were also more sensitive to lysis at hyperosmotic conditions and hypervesiculated compared to the parent wild-type bacteria. In conclusion, our results suggest that P5 is important for bacterial OM stability, which ultimately affects the membrane proteome and NTHi pathogenesis.
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Affiliation(s)
- Yu-Ching Su
- Department of Translational Medicine, Clinical Microbiology, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Mahendar Kadari
- Department of Translational Medicine, Clinical Microbiology, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Megan L. Straw
- Department of Translational Medicine, Clinical Microbiology, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Martina Janoušková
- Department of Translational Medicine, Clinical Microbiology, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Sandra Jonsson
- Department of Translational Medicine, Clinical Microbiology, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Oskar Thofte
- Department of Translational Medicine, Clinical Microbiology, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Farshid Jalalvand
- Department of Translational Medicine, Clinical Microbiology, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Erika Matuschek
- European Committee on Antimicrobial Susceptibility Testing (EUCAST) Development Laboratory, c/o Clinical Microbiology, Central Hospital, Växjö, Sweden
| | - Linda Sandblad
- Department of Chemistry and The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Ákos Végvári
- Division of Chemistry I, Department of Medical Biochemistry & Biophysics (MBB), Proteomics Biomedicum, Karolinska Institute, Stockholm, Sweden
| | - Roman A. Zubarev
- Division of Chemistry I, Department of Medical Biochemistry & Biophysics (MBB), Proteomics Biomedicum, Karolinska Institute, Stockholm, Sweden
| | - Kristian Riesbeck
- Department of Translational Medicine, Clinical Microbiology, Faculty of Medicine, Lund University, Malmö, Sweden
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Brogan AP, Rudner DZ. Regulation of peptidoglycan hydrolases: localization, abundance, and activity. Curr Opin Microbiol 2023; 72:102279. [PMID: 36812681 PMCID: PMC10031507 DOI: 10.1016/j.mib.2023.102279] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 02/22/2023]
Abstract
Most bacteria are surrounded by a cell wall composed of peptidoglycan (PG) that specifies shape and protects the cell from osmotic rupture. Growth, division, and morphogenesis are intimately linked to the synthesis of this exoskeleton but also its hydrolysis. The enzymes that cleave the PG meshwork require careful control to prevent aberrant hydrolysis and loss of envelope integrity. Bacteria employ diverse mechanisms to control the activity, localization, and abundance of these potentially autolytic enzymes. Here, we discuss four examples of how cells integrate these control mechanisms to finely tune cell wall hydrolysis. We highlight recent advances and exciting avenues for future investigation.
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Affiliation(s)
- Anna P Brogan
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - David Z Rudner
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA.
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Identification of Subunits for Novel Universal Vaccines against Three Predominant Serogroups and the Emerging O145 among Avian Pathogenic Escherichia coli by Pan-RV Pipeline. Appl Environ Microbiol 2023; 89:e0106122. [PMID: 36533928 PMCID: PMC9888223 DOI: 10.1128/aem.01061-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Avian pathogenic Escherichia coli, a causative agent of avian colibacillosis, has been causing serious economic losses in the poultry industry. The increase in multidrug-resistant isolates and the complexity of the serotypes of this pathogen, especially the recently reported emergence of a newly predominant serogroup of O145, make the control of this disease difficult. To address this challenge, a high-throughput screening approach, called Pan-RV (Reverse vaccinology based on pangenome analysis), is proposed to search for universal protective antigens against the three traditional serogroups and the newly emerged O145. Using this approach, a total of 61 proteins regarded as probable antigens against the four important serogroups were screened from the core genome of 127 Avian pathogenic Escherichia coli (APEC) genomes, and six were verified by Western blots using antisera. Overall, our research will provide a foundation for the development of an APEC subunit vaccine against avian colibacillosis. Given the exponential growth of whole-genome sequencing (WGS) data, our Pan-RV pipeline will make screening of bacterial vaccine candidates inexpensive, rapid, and efficient. IMPORTANCE With the emergence of drug resistance and the newly predominant serogroup O145, the control of Avian pathogenic Escherichia coli is facing a serious challenge; an efficient immunological method is urgently needed. Here, for the first time, we propose a high-throughput screening approach to search for universal protective antigens against the three traditional serogroups and the newly emerged O145. Importantly, using this approach, a total of 61 proteins regarded as probable antigens against the four important serogroups were screened, and three were shown to be immunoreactive with all antisera (covering the four serogroups), thereby providing a foundation for the development of APEC subunit vaccines against avian colibacillosis. Further, our Pan-RV pipeline will provide immunological control strategies for pathogens with complex and variable genetic backgrounds such as Escherichia coli and will make screening of bacterial vaccine candidates more inexpensive, rapid, and efficient.
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Guan S, Zhong L, Yu H, Wang L, Jin Y, Liu J, Xiang H, Yu H, Wang L, Wang D. Molecular docking and proteomics reveals the synergistic antibacterial mechanism of theaflavin with β-lactam antibiotics against MRSA. Front Microbiol 2022; 13:993430. [PMID: 36452924 PMCID: PMC9702817 DOI: 10.3389/fmicb.2022.993430] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 10/11/2022] [Indexed: 04/09/2024] Open
Abstract
Recurrent epidemics of methicillin-resistant Staphylococcus aureus (S. aureus) (MRSA) have illustrated that the effectiveness of antibiotics in clinical application is rapidly fading. A feasible approach is to combine natural products with existing antibiotics to achieve an antibacterial effect. In this molecular docking study, we found that theaflavin (TF) preferentially binds the allosteric site of penicillin-binding protein 2a (PBP2a), inducing the PBP2a active site to open, which is convenient for β-lactam antibiotics to treat MRSA infection, instead of directly exerting antibacterial activity at the active site. Subsequent TMT-labeled proteomics analysis showed that TF treatment did not significantly change the landscape of the S. aureus USA300 proteome. Checkerboard dilution tests and kill curve assays were performed to validate the synergistic effect of TF and ceftiofur, and the fractional inhibitory concentration index (FICI) was 0.1875. The antibacterial effect of TF combined with ceftiofur was better than that of single-drug treatment in vitro. In addition, TF effectively enhanced the activity of ceftiofur in a mouse model of MRSA-induced pneumonia. Our findings provide a potential therapeutic strategy to combine existing antibiotics with natural products to resolve the prevalent infections of multidrug-resistant pathogens.
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Affiliation(s)
- Shuhan Guan
- College of Animal Science, Jilin University, Changchun, China
| | - Ling Zhong
- College of Animal Science, Jilin University, Changchun, China
| | - Hangqian Yu
- College of Animal Science, Jilin University, Changchun, China
| | - Li Wang
- Changchun University of Chinese Medicine, Changchun, China
| | - Yajing Jin
- College of Animal Science, Jilin University, Changchun, China
| | - Jingyu Liu
- College of Animal Science, Jilin University, Changchun, China
| | - Hua Xiang
- College of Animal Medicine, Jilin Agricultural University, Changchun, China
| | - Hao Yu
- College of Animal Science, Jilin University, Changchun, China
| | - Lin Wang
- State Key Laboratory for Zoonotic Diseases, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Dacheng Wang
- College of Animal Science, Jilin University, Changchun, China
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7
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Bolourchi N, Fereshteh S, Noori Goodarzi N, Badmasti F. Subtractive genomic analysis for computational identification of putative immunogenic targets against clinical Enterobacter cloacae complex. PLoS One 2022; 17:e0275749. [PMID: 36228013 PMCID: PMC9560131 DOI: 10.1371/journal.pone.0275749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 09/22/2022] [Indexed: 11/06/2022] Open
Abstract
Background Enterobacter is a major nosocomial genus of Enterobacteriaceae responsible for a variety of nosocomial infections, particularly in prolonged hospitalized patients in the intensive care units. Since current antibiotics have failed treating colistin- and carbapenem-resistant Enterobacteriaceae, efforts are underway to find suitable alternative strategies. Therefore, this study conducted a reverse vaccinology (RV) to identify novel and putative immunogenic targets using core proteome of 20 different sequence types (STs) of clinical Enterobacter spp. Moreover, we introduced a structural-based approach for exploration of potential vaccine candidates against the Enterobacteriaceae family using their conserved domain analysis. Results A number of 2616 core coding sequences (CDSs) were retrieved from 20 clinical strains of Enterobacter spp. with a similarity of ≥ 50%. Nine proteins with a score of ≥ 20 considered as the shortlisted proteins based on the quartile scoring method, including three TonB-dependent receptors, WP_008500981.1, WP_058690971.1 and WP_058679571.1; one YjbH domain-containing protein, WP_110108068.1; three flagellar proteins, WP_088207510.1, WP_033145204.1 and WP_058679632.1; one spore-coat U domain-containing protein, WP_039266612.1; and one DD-metalloendopeptidase family protein, WP_025912449.1. In this study, proteins WP_058690971.1 and WP_110108068.1 were detected as the top candidates with regard to immune stimulation and interactions with TLRs. However, their efficacy is remaining to be evaluated experimentally. Conclusions Our investigation introduced common ferrichrome porins with high sequence similarity as potential vaccine candidates against the Enterobacteriaceae family. These proteins belong to the iron acquisition system and possess all criteria of suitable vaccine targets. Therefore, they need to be specifically paid attention for vaccine development against clinically important members of Enterobacteriaceae family.
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Affiliation(s)
- Negin Bolourchi
- Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran
| | | | - Narjes Noori Goodarzi
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Farzad Badmasti
- Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran
- Microbiology Research Center (MRC), Pasteur Institute of Iran, Tehran, Iran
- * E-mail:
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Jalalvand F, Su YC, Manat G, Chernobrovkin A, Kadari M, Jonsson S, Janousková M, Rutishauser D, Semsey S, Løbner-Olesen A, Sandblad L, Flärdh K, Mengin-Lecreulx D, Zubarev RA, Riesbeck K. Protein domain-dependent vesiculation of Lipoprotein A, a protein that is important in cell wall synthesis and fitness of the human respiratory pathogen Haemophilus influenzae. Front Cell Infect Microbiol 2022; 12:984955. [PMID: 36275016 PMCID: PMC9585305 DOI: 10.3389/fcimb.2022.984955] [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: 07/02/2022] [Accepted: 09/15/2022] [Indexed: 11/13/2022] Open
Abstract
The human pathogen Haemophilus influenzae causes respiratory tract infections and is commonly associated with prolonged carriage in patients with chronic obstructive pulmonary disease. Production of outer membrane vesicles (OMVs) is a ubiquitous phenomenon observed in Gram-negative bacteria including H. influenzae. OMVs play an important role in various interactions with the human host; from neutralization of antibodies and complement activation to spread of antimicrobial resistance. Upon vesiculation certain proteins are found in OMVs and some proteins are retained at the cell membrane. The mechanism for this phenomenon is not fully elucidated. We employed mass spectrometry to study vesiculation and the fate of proteins in the outer membrane. Functional groups of proteins were differentially distributed on the cell surface and in OMVs. Despite its supposedly periplasmic and outer membrane location, we found that the peptidoglycan synthase-activator Lipoprotein A (LpoA) was accumulated in OMVs relative to membrane fractions. A mutant devoid of LpoA lost its fitness as revealed by growth and electron microscopy. Furthermore, high-pressure liquid chromatography disclosed a lower concentration (55%) of peptidoglycan in the LpoA-deficient H. influenzae compared to the parent wild type bacterium. Using an LpoA-mNeonGreen fusion protein and fluorescence microscopy, we observed that LpoA was enriched in “foci” in the cell envelope, and further located in the septum during cell division. To define the fate of LpoA, C-terminally truncated LpoA-variants were constructed, and we found that the LpoA C-terminal domain promoted optimal transportation to the OMVs as revealed by flow cytometry. Taken together, our study highlights the importance of LpoA for H. influenzae peptidoglycan biogenesis and provides novel insights into cell wall integrity and OMV production.
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Affiliation(s)
- Farshid Jalalvand
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Yu-Ching Su
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Guillaume Manat
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Alexey Chernobrovkin
- Physiological Chemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Mahendar Kadari
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Sandra Jonsson
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Martina Janousková
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Dorothea Rutishauser
- Physiological Chemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Szabolcs Semsey
- Centre for Bacterial Stress Response and Persistence, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Anders Løbner-Olesen
- Centre for Bacterial Stress Response and Persistence, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | | | - Klas Flärdh
- Department of Biology, Lund University, Lund, Sweden
| | - Dominique Mengin-Lecreulx
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Roman A. Zubarev
- Physiological Chemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Kristian Riesbeck
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
- *Correspondence: Kristian Riesbeck,
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Thompson C, George S, White ML, Eswara PJ, Ouyang Z. BB0761, a MepM homolog, contributes to Borrelia burgdorferi cell division and mammalian infectivity. Mol Microbiol 2022; 117:1405-1418. [PMID: 35510701 PMCID: PMC9794411 DOI: 10.1111/mmi.14916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 05/01/2022] [Accepted: 05/02/2022] [Indexed: 12/30/2022]
Abstract
M23 family endopeptidases play important roles in cell division and separation in a wide variety of bacteria. Recent studies have suggested that these proteins also contribute to bacterial virulence. However, the biological function of M23 peptidases in pathogenic spirochetes remains unexplored. Here, we describe Borrelia burgdorferi, the bacterial pathogen causing Lyme disease, requires a putative M23 family homolog, BB0761, for spirochete morphology and cell division. Indeed, the inactivation of bb0761 led to an aberrant filamentous phenotype as well as the impairment of B. burgdorferi growth in vitro. These phenotypes were complemented not only with B. burgdorferi bb0761, but also with the mepM gene from E. coli. Moreover, the bb0761 mutant showed a complete loss of infectivity in a murine model of Lyme borreliosis. Resistance of the mutant to osmotic and oxidative stresses was markedly reduced. Our combined results indicate that BB0761 contributes to B. burgdorferi cell division and virulence.
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Affiliation(s)
- Christina Thompson
- Department of Molecular Medicine, University of South Florida, Tampa, Florida, USA
| | - Sierra George
- Department of Molecular Medicine, University of South Florida, Tampa, Florida, USA
| | - Maria L. White
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Prahathees J. Eswara
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Zhiming Ouyang
- Department of Molecular Medicine, University of South Florida, Tampa, Florida, USA
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Papadopoulos AO, Ealand C, Gordhan BG, VanNieuwenhze M, Kana BD. Characterisation of a putative M23-domain containing protein in Mycobacterium tuberculosis. PLoS One 2021; 16:e0259181. [PMID: 34784363 PMCID: PMC8594824 DOI: 10.1371/journal.pone.0259181] [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: 08/16/2020] [Accepted: 10/14/2021] [Indexed: 12/01/2022] Open
Abstract
Mycobacterium tuberculosis, the causative agent of tuberculosis remains a global health concern, further compounded by the high rates of HIV-TB co-infection and emergence of multi- and extensive drug resistant TB, all of which have hampered efforts to eradicate this disease. As a result, novel anti-tubercular interventions are urgently required, with the peptidoglycan component of the M. tuberculosis cell wall emerging as an attractive drug target. Peptidoglycan M23 endopeptidases can function as active cell wall hydrolases or degenerate activators of hydrolases in a variety of bacteria, contributing to important processes such as bacterial growth, division and virulence. Herein, we investigate the function of the Rv0950-encoded putative M23 endopeptidase in M. tuberculosis. In silico analysis revealed that this protein is conserved in mycobacteria, with a zinc-binding catalytic site predictive of hydrolytic activity. Transcript analysis indicated that expression of Rv0950c was elevated during lag and log phases of growth and reduced in stationary phase. Deletion of Rv0950c yielded no defects in growth, colony morphology, antibiotic susceptibility or intracellular survival but caused a reduction in cell length. Staining with a monopeptide-derived fluorescent D-amino acid, which spatially reports on sites of active PG biosynthesis or repair, revealed an overall reduction in uptake of the probe in ΔRv0950c. When stained with a dipeptide probe in the presence of cell wall damaging agents, the ΔRv0950c mutant displayed reduced sidewall labelling. As bacterial peptidoglycan metabolism is important for survival and pathogenesis, the role of Rv0950c and other putative M23 endopeptidases in M. tuberculosis should be explored further.
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Affiliation(s)
- Andrea Olga Papadopoulos
- Faculty of Health Sciences, DSI/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, University of the Witwatersrand, National Health Laboratory Service, Johannesburg, South Africa
| | - Christopher Ealand
- Faculty of Health Sciences, DSI/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, University of the Witwatersrand, National Health Laboratory Service, Johannesburg, South Africa
| | - Bhavna Gowan Gordhan
- Faculty of Health Sciences, DSI/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, University of the Witwatersrand, National Health Laboratory Service, Johannesburg, South Africa
| | - Michael VanNieuwenhze
- Department of Chemistry, Indiana University Bloomington, Bloomington, Indiana, United States of America
| | - Bavesh Davandra Kana
- Faculty of Health Sciences, DSI/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, University of the Witwatersrand, National Health Laboratory Service, Johannesburg, South Africa
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Figueroa-Cuilan WM, Randich AM, Dunn CM, Santiago-Collazo G, Yowell A, Brown PJB. Diversification of LytM Protein Functions in Polar Elongation and Cell Division of Agrobacterium tumefaciens. Front Microbiol 2021; 12:729307. [PMID: 34489918 PMCID: PMC8416486 DOI: 10.3389/fmicb.2021.729307] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 07/26/2021] [Indexed: 12/05/2022] Open
Abstract
LytM-domain containing proteins are LAS peptidases (lysostaphin-type enzymes, D-Ala-D-Ala metallopeptidases, and sonic hedgehog) and are known to play diverse roles throughout the bacterial cell cycle through direct or indirect hydrolysis of the bacterial cell wall. A subset of the LytM factors are catalytically inactive but regulate the activity of other cell wall hydrolases and are classically described as cell separation factors NlpD and EnvC. Here, we explore the function of four LytM factors in the alphaproteobacterial plant pathogen Agrobacterium tumefaciens. An LmdC ortholog (Atu1832) and a MepM ortholog (Atu4178) are predicted to be catalytically active. While Atu1832 does not have an obvious function in cell growth or division, Atu4178 is essential for polar growth and likely functions as a space-making endopeptidase that cleaves amide bonds in the peptidoglycan cell wall during elongation. The remaining LytM factors are degenerate EnvC and NlpD orthologs. Absence of these proteins results in striking phenotypes indicative of misregulation of cell division and growth pole establishment. The deletion of an amidase, AmiC, closely phenocopies the deletion of envC suggesting that EnvC might regulate AmiC activity. The NlpD ortholog DipM is unprecedently essential for viability and depletion results in the misregulation of early stages of cell division, contrasting with the canonical view of DipM as a cell separation factor. Finally, we make the surprising observation that absence of AmiC relieves the toxicity induced by dipM overexpression. Together, these results suggest EnvC and DipM may function as regulatory hubs with multiple partners to promote proper cell division and establishment of polarity.
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Affiliation(s)
| | - Amelia M. Randich
- Department of Biology, University of Scranton, Scranton, PA, United States
| | - Caroline M. Dunn
- Division of Biological Sciences, University of Missouri, Columbia, MO, United States
| | - Gustavo Santiago-Collazo
- Division of Biological Sciences, University of Missouri, Columbia, MO, United States
- Molecular Pathogenesis and Therapeutics Graduate Program, University of Missouri, Columbia, MO, United States
| | - Andrew Yowell
- Division of Biological Sciences, University of Missouri, Columbia, MO, United States
| | - Pamela J. B. Brown
- Division of Biological Sciences, University of Missouri, Columbia, MO, United States
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12
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Orellana CA, Zaragoza NE, Licona-Cassani C, Palfreyman RW, Cowie N, Moonen G, Moutafis G, Power J, Nielsen LK, Marcellin E. Time-course transcriptomics reveals that amino acids catabolism plays a key role in toxinogenesis and morphology in Clostridium tetani. ACTA ACUST UNITED AC 2020; 47:1059-1073. [DOI: 10.1007/s10295-020-02330-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 11/02/2020] [Indexed: 10/23/2022]
Abstract
Abstract
Tetanus is a fatal disease caused by Clostridium tetani infections. To prevent infections, a toxoid vaccine, developed almost a century ago, is routinely used in humans and animals. The vaccine is listed in the World Health Organisation list of Essential Medicines and can be produced and administered very cheaply in the developing world for less than one US Dollar per dose. Recent developments in both analytical tools and frameworks for systems biology provide industry with an opportunity to gain a deeper understanding of the parameters that determine C. tetani virulence and physiological behaviour in bioreactors. Here, we compared a traditional fermentation process with a fermentation medium supplemented with five heavily consumed amino acids. The experiment demonstrated that amino acid catabolism plays a key role in the virulence of C. tetani. The addition of the five amino acids favoured growth, decreased toxin production and changed C. tetani morphology. Using time-course transcriptomics, we created a “fermentation map”, which shows that the tetanus toxin transcriptional regulator BotR, P21 and the tetanus toxin gene was downregulated. Moreover, this in-depth analysis revealed potential genes that might be involved in C. tetani virulence regulation. We observed differential expression of genes related to cell separation, surface/cell adhesion, pyrimidine biosynthesis and salvage, flagellar motility, and prophage genes. Overall, the fermentation map shows that, mediated by free amino acid concentrations, virulence in C. tetani is regulated at the transcriptional level and affects a plethora of metabolic functions.
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Affiliation(s)
- Camila A Orellana
- grid.1003.2 0000 0000 9320 7537 Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland 4072 Brisbane QLD Australia
- grid.7870.8 0000 0001 2157 0406 Department of Chemical and Bioprocess Engineering, School of Engineering Pontificia Universidad Católica de Chile Santiago Chile
| | - Nicolas E Zaragoza
- grid.1003.2 0000 0000 9320 7537 Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland 4072 Brisbane QLD Australia
| | - Cuauhtemoc Licona-Cassani
- grid.1003.2 0000 0000 9320 7537 Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland 4072 Brisbane QLD Australia
- grid.419886.a 0000 0001 2203 4701 Centro de Biotecnología FEMSA Tecnológico de Monterrey Nuevo León Mexico
| | - Robin W Palfreyman
- grid.1003.2 0000 0000 9320 7537 Metabolomics Australia The University of Queensland 4072 Brisbane QLD Australia
| | - Nicholas Cowie
- grid.1003.2 0000 0000 9320 7537 Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland 4072 Brisbane QLD Australia
| | - Glenn Moonen
- Zoetis. 45 Poplar Road 3052 Parkville VIC Australia
| | | | - John Power
- Zoetis. 45 Poplar Road 3052 Parkville VIC Australia
| | - Lars K Nielsen
- grid.1003.2 0000 0000 9320 7537 Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland 4072 Brisbane QLD Australia
- grid.1003.2 0000 0000 9320 7537 Metabolomics Australia The University of Queensland 4072 Brisbane QLD Australia
- grid.5170.3 0000 0001 2181 8870 The Novo Nordisk Foundation Centre for Biosustainability Technical University of Denmark Kgs. Lyngby Denmark
| | - Esteban Marcellin
- grid.1003.2 0000 0000 9320 7537 Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland 4072 Brisbane QLD Australia
- grid.1003.2 0000 0000 9320 7537 Metabolomics Australia The University of Queensland 4072 Brisbane QLD Australia
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13
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Fereshteh S, Abdoli S, Shahcheraghi F, Ajdary S, Nazari M, Badmasti F. New putative vaccine candidates against Acinetobacter baumannii using the reverse vaccinology method. Microb Pathog 2020; 143:104114. [DOI: 10.1016/j.micpath.2020.104114] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 02/15/2020] [Accepted: 03/01/2020] [Indexed: 01/15/2023]
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14
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A Peptidoglycan Amidase Activator Impacts Salmonella enterica Serovar Typhimurium Gut Infection. Infect Immun 2020; 88:IAI.00187-20. [PMID: 32284369 DOI: 10.1128/iai.00187-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 04/05/2020] [Indexed: 12/12/2022] Open
Abstract
Salmonella enterica serovar Typhimurium is an important foodborne pathogen that causes diarrhea. S. Typhimurium elicits inflammatory responses and colonizes the gut lumen by outcompeting the microbiota. Although evidence is accumulating with regard to the underlying mechanism, the infectious stage has not been adequately defined. Peptidoglycan amidases are widely distributed among bacteria and play a prominent role in peptidoglycan maintenance by hydrolyzing peptidoglycans. Amidase activation is required for the regulation of at least one of two cognate activators, NlpD or EnvC (also called YibP). Recent studies established that the peptidoglycan amidase AmiC-mediated cell division specifically confers a fitness advantage on S Typhimurium in the inflamed gut. However, it remains unknown which cognate activators are involved in the amidase activation and how the activators influence Salmonella sp. pathogenesis. Here, we characterize the role of two activators, NlpD and EnvC, in S Typhimurium cell division and gut infection. EnvC was found to contribute to cell division of S Typhimurium cells through the activation of AmiA and AmiC. The envC mutant exhibited impairments in gut infection, including a gut colonization defect and reduced ability to elicit inflammatory responses. Importantly, the colonization defect of the envC mutant was unrelated to the microbiota but was conferred by attenuated motility and chemotaxis of S Typhimurium cells, which were not observed in the amiA amiC mutant. Furthermore, the envC mutant was impaired in its induction of mucosal inflammation and sustained gut colonization. Collectively, our findings provide a novel insight into the peptidoglycan amidase/cognate activator circuits and their dependent pathogenesis.
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15
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Cao Y, Gao L, Zhang L, Zhou L, Yang J, Deng L, Zhao J, Qi C, Liu J. Genome-wide screening of lipoproteins in Actinobacillus pleuropneumoniae identifies three antigens that confer protection against virulent challenge. Sci Rep 2020; 10:2343. [PMID: 32047221 PMCID: PMC7012816 DOI: 10.1038/s41598-020-58968-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 01/23/2020] [Indexed: 11/24/2022] Open
Abstract
Actinobacillus pleuropneumoniae is an important veterinary pathogen that causes porcine pleuropneumonia. Lipoproteins of bacterial pathogens play pleiotropic roles in the infection process. In addition, many bacterial lipoproteins are antigenic and immunoprotective. Therefore, characterization of lipoproteins is a promising strategy for identification of novel vaccine candidates or diagnostic markers. We cloned 58 lipoproteins from A. pleuropneumoniae JL03 (serovar 3) and expressed them in Escherichia coli. Five proteins with strong positive signals in western blotting analysis were used to immunize mice. These proteins elicited significant antibody responses, and three of them (APJL_0922, APJL_1380 and APJL_1976) generated efficient immunoprotection in mice against lethal heterologous challenge with A. pleuropneumoniae 4074 (serovar 1), both in the active and passive immunization assays. Then immunogenicity of these three lipoproteins (APJL_0922, APJL_1380 and APJL_1976) were further tested in pigs. Results showed that these proteins elicited considerable humoral immune responses and effective protective immunity against virulent A. pleuropneumoniae challenge. Our findings suggest that these three novel lipoproteins could be potential subunit vaccine candidates.
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Affiliation(s)
- Yurou Cao
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, China
| | - Lulu Gao
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, China
| | - Li Zhang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, China
| | - Lixiang Zhou
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, China
| | - Jihong Yang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, China
| | - Lingfu Deng
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, China
| | - Jin Zhao
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, China
| | - Chao Qi
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, China.
| | - Jinlin Liu
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, China.
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16
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Baddal B. Characterization of biofilm formation and induction of apoptotic DNA fragmentation by nontypeable Haemophilus influenzae on polarized human airway epithelial cells. Microb Pathog 2020; 141:103985. [PMID: 31968224 DOI: 10.1016/j.micpath.2020.103985] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 01/14/2020] [Accepted: 01/15/2020] [Indexed: 10/25/2022]
Abstract
Nontypeable Haemophilus influenzae (NTHi) is a common airway commensal and opportunistic pathogen that persists within biofilm communities in vivo. Biofilm studies so far are mainly based on assays on plastic surfaces. The aim of this work was to investigate the capacity of clinical NTHi strains to form biofilm structures on polarized Calu-3 human airway epithelial cells and primary normal human bronchial epithelial cells and to characterize the biofilm architecture. Formation of adherent NTHi biofilms post colonization of host cells at multiple time-points was evaluated using confocal laser scanning microscopy and electron microscopy. NTHi biofilms were analyzed in terms of biofilm height and presence of extracellular matrix components, and their apoptotic effects on epithelial cells were measured by TUNEL assay. Strain Fi176 was observed to form robust biofilms on airway epithelia over time, while disrupting the integrity of Calu-3 monolayer by 72 h of co-culture. NTHi biofilms were observed to induce apoptotic DNA fragmentation in host cells at 24 h post infection. Biofilm formation on cell monolayers by Fi176ΔpilA strain was markedly reduced compared to WT strain. Biofilm inhibition and disruption assays by crystal violet staining indicated that DNA and proteins are part of NTHi biofilms in vitro. Our findings highlight critical stages of NTHi pathogenesis following host colonization and provide useful biofilm models for future antimicrobial drug discovery investigations.
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Affiliation(s)
- Buket Baddal
- Department of Medical Microbiology and Clinical Microbiology, Faculty of Medicine, Near East University, 99138, Nicosia, Cyprus; Microbial Pathogenesis Research Group, DESAM Institute, Near East University, Nicosia, Cyprus.
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17
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Delgado L, Baeza N, Pérez-Cruz C, López-Iglesias C, Mercadé E. Cryo-transmission Electron Microscopy of Outer-inner Membrane Vesicles Naturally Secreted by Gram-negative Pathogenic Bacteria. Bio Protoc 2019; 9:e3367. [PMID: 33654864 DOI: 10.21769/bioprotoc.3367] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 08/24/2019] [Accepted: 08/13/2019] [Indexed: 12/12/2022] Open
Abstract
A protocol was developed to visualize and analyze the structure of membrane vesicles (MVs) from Gram-negative bacteria. It is now accepted that these micrometric spherical vesicles are commonly produced by cells from all three domains of life, so the protocol could be useful in the study of vesicles produced by eukaryotes and archaea as well as bacteria. The multiplicity of functions performed by MVs, related to cell communication, interaction with the immune system, pathogenesis, and nutrient acquisition, among others, has made MVs a hot topic of research. Due to their small size (25-300 nm), the observation of MVs requires electron microscopy and is usually performed by transmission electron microscopy (TEM) of negatively stained MVs. Other protocols applied for their visualization include scanning electron microscopy, TEM after fixation and embedding of vesicles, or even atomic force microscopy. In some of these techniques, vesicle structure is altered by drying, while others are time-consuming and most of them can generate artifacts. Cryo-TEM after plunge freezing allows the visualization of samples embedded in a thin film of vitreous ice, which preserves their native cellular structures and provides the highest available resolution for the imaging. This is achieved by very high cooling rates that turn the intrinsic water of cells into vitreous ice, avoiding crystal formation and phase segregation between water and solutes. In addition to other types of characterization, an accurate knowledge of MV structure, which can be obtained by this protocol, is essential for MV application in different fields.
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Affiliation(s)
- Lidia Delgado
- Crio-Microscòpia Electrònica, Centres Científics i Tecnològics, Universitat de Barcelona, Barcelona, Spain
| | - Nicolás Baeza
- Secció de Microbiologia, Departament de Biologia, Sanitat i Medi Ambient, Universitat de Barcelona, Barcelona, Spain
| | - Carla Pérez-Cruz
- Secció de Microbiologia, Departament de Biologia, Sanitat i Medi Ambient, Universitat de Barcelona, Barcelona, Spain
| | - Carmen López-Iglesias
- The Institute of Nanoscopy, Maastricht University, 6211 LK, Maastricht, the Netherlands
| | - Elena Mercadé
- Secció de Microbiologia, Departament de Biologia, Sanitat i Medi Ambient, Universitat de Barcelona, Barcelona, Spain
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18
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Seib KL, Haag AF, Oriente F, Fantappiè L, Borghi S, Semchenko EA, Schulz BL, Ferlicca F, Taddei AR, Giuliani MM, Pizza M, Delany I. The meningococcal vaccine antigen GNA2091 is an analogue of YraP and plays key roles in outer membrane stability and virulence. FASEB J 2019; 33:12324-12335. [DOI: 10.1096/fj.201900669r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kate L. Seib
- Institute for GlycomicsGriffith UniversityGold CoastQueenslandAustralia
| | | | | | | | | | | | - Benjamin L. Schulz
- School of Chemistry and Molecular BiosciencesThe University of QueenslandBrisbaneQueenslandAustralia
| | | | - Anna Rita Taddei
- Interdepartmental Centre of Electron Microscopy (CIME)Tuscia UniversityTusciaItaly
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19
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Wang M, Fang C, Ma B, Luo X, Hou Z. Regulation of cytokinesis: FtsZ and its accessory proteins. Curr Genet 2019; 66:43-49. [PMID: 31209564 DOI: 10.1007/s00294-019-01005-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 06/08/2019] [Accepted: 06/12/2019] [Indexed: 12/11/2022]
Abstract
Bacterial cell division is a highly controlled process regulated accurately by a diverse array of proteins spatially and temporally working together. Among these proteins, FtsZ is recognized as a cytoskeleton protein because it can assemble into a ring-like structure called Z-ring at midcell. Z-ring recruits downstream proteins, thus forming a multiprotein complex termed the divisome. When the Z-ring scaffold is established and the divisome matures, peptidoglycan (PG) biosynthesis and chromosome segregation are triggered. In this review, we focus on multiple interactions between FtsZ and its accessory proteins in bacterial cell cytokinesis, including FtsZ localization, Z-ring formation and stabilization, PG biosynthesis, and chromosome segregation. Understanding the interactions among these proteins may help discover superior targets on treating bacterial infectious diseases.
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Affiliation(s)
- Mingzhi Wang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China
| | - Chao Fang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China
| | - Bo Ma
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China
| | - Xiaoxing Luo
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China
| | - Zheng Hou
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China.
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20
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Tidhar A, Levy Y, Zauberman A, Vagima Y, Gur D, Aftalion M, Israeli O, Chitlaru T, Ariel N, Flashner Y, Zvi A, Mamroud E. Disruption of the NlpD lipoprotein of the plague pathogen Yersinia pestis affects iron acquisition and the activity of the twin-arginine translocation system. PLoS Negl Trop Dis 2019; 13:e0007449. [PMID: 31170147 PMCID: PMC6553720 DOI: 10.1371/journal.pntd.0007449] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 05/08/2019] [Indexed: 11/29/2022] Open
Abstract
We have previously shown that the cell morphogenesis NlpD lipoprotein is essential for virulence of the plague bacteria, Yersinia pestis. To elucidate the role of NlpD in Y. pestis pathogenicity, we conducted a whole-genome comparative transcriptome analysis of the wild-type Y. pestis strain and an nlpD mutant under conditions mimicking early stages of infection. The analysis suggested that NlpD is involved in three phenomena: (i) Envelope stability/integrity evidenced by compensatory up-regulation of the Cpx and Psp membrane stress-response systems in the mutant; (ii) iron acquisition, supported by modulation of iron metabolism genes and by limited growth in iron-deprived medium; (iii) activity of the twin-arginine (Tat) system, which translocates folded proteins across the cytoplasmic membrane. Virulence studies of Y. pestis strains mutated in individual Tat components clearly indicated that the Tat system is central in Y. pestis pathogenicity and substantiated the assumption that NlpD essentiality in iron utilization involves the activity of the Tat system. This study reveals a new role for NlpD in Tat system activity and iron assimilation suggesting a modality by which this lipoprotein is involved in Y. pestis pathogenesis. We have previously shown that the NlpD lipoprotein, which is involved in the regulation of cell morphogenesis, is essential for virulence of the plague bacteria, Yersinia pestis. To uncover the role of NlpD in Y. pestis pathogenicity, we conducted a whole-genome comparative transcriptome analysis as well as phenotypic and virulence evaluation analyses of the nlpD and related mutants. The study reveals a new role for the Y. pestis NlpD lipoprotein in iron assimilation and Tat system activity.
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Affiliation(s)
- Avital Tidhar
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
- * E-mail: (AT); (EM)
| | - Yinon Levy
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Ayelet Zauberman
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Yaron Vagima
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - David Gur
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Moshe Aftalion
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Ofir Israeli
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Theodor Chitlaru
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Naomi Ariel
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Yehuda Flashner
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Anat Zvi
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Emanuelle Mamroud
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
- * E-mail: (AT); (EM)
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21
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Impact of Combined Acidic and Hyperosmotic Shock Conditions on the Proteome of Listeria monocytogenesATCC 19115 in a Time-Course Study. J FOOD QUALITY 2019. [DOI: 10.1155/2019/3075028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Listeria monocytogenescan cause listeriosis in humans through consumption of contaminated food and can adapt to and grow under a wide array of physiochemical stresses. Consequently, it causes persistent food safety issues and requires vigilant sanitation processes to be in place, especially for the manufacture of high-risk food products. In this study, the global proteomic responses of the food-borne pathogenL. monocytogenesstrain ATCC 19115 were determined when exposed to nonthermal inactivation. This process was examined in the early stationary growth phase with the strain placed under simultaneous exposure to low pH (pH 3.5) and high salinity (aw0.900, 14% NaCl). Proteomic responses, measured using iTRAQ techniques, were conducted over a time course (5 min, 30 min, and 1 h at 25°C). The enumeration results showed that, at 5 min, cells underwent initial rapid inactivation by 1.2 log units and 2.5 log units after 30 min, and after that, culturability remained stable when sampled at 1 h. From the iTRAQ results, the proteome level changes that occur rapidly during the inactivation process mainly affected prophage, cell defense/detoxification, carbohydrate-related metabolism, transporter proteins, phosphotransferase systems, cell wall biogenesis, and specific cell surface proteins. Pathway map analysis revealed that several pathways are affected including pentose and glucuronate interconversions, glycolysis/gluconeogenesis, pyruvate metabolism, valine, leucine and isoleucine biosynthesis, oxidative phosphorylation, and proteins associated with bacterial invasion of epithelial cells and host survival. Proteome profiling provided a better understanding of the physiological responses of this pathogen to adapt to lethal nonthermal environments and indicates the need to improve food processing and storage methods, especially for non- or minimally thermally processed foods.
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22
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Juan C, Torrens G, Barceló IM, Oliver A. Interplay between Peptidoglycan Biology and Virulence in Gram-Negative Pathogens. Microbiol Mol Biol Rev 2018; 82:e00033-18. [PMID: 30209071 PMCID: PMC6298613 DOI: 10.1128/mmbr.00033-18] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The clinical and epidemiological threat of the growing antimicrobial resistance in Gram-negative pathogens, particularly for β-lactams, the most frequently used and relevant antibiotics, urges research to find new therapeutic weapons to combat the infections caused by these microorganisms. An essential previous step in the development of these therapeutic solutions is to identify their potential targets in the biology of the pathogen. This is precisely what we sought to do in this review specifically regarding the barely exploited field analyzing the interplay among the biology of the peptidoglycan and related processes, such as β-lactamase regulation and virulence. Hence, here we gather, analyze, and integrate the knowledge derived from published works that provide information on the topic, starting with those dealing with the historically neglected essential role of the Gram-negative peptidoglycan in virulence, including structural, biogenesis, remodeling, and recycling aspects, in addition to proinflammatory and other interactions with the host. We also review the complex link between intrinsic β-lactamase production and peptidoglycan metabolism, as well as the biological costs potentially associated with the expression of horizontally acquired β-lactamases. Finally, we analyze the existing evidence from multiple perspectives to provide useful clues for identifying targets enabling the future development of therapeutic options attacking the peptidoglycan-virulence interconnection as a key weak point of the Gram-negative pathogens to be used, if not to kill the bacteria, to mitigate their capacity to produce severe infections.
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Affiliation(s)
- Carlos Juan
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
| | - Gabriel Torrens
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
| | - Isabel Maria Barceló
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
| | - Antonio Oliver
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
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23
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Tossavainen H, Raulinaitis V, Kauppinen L, Pentikäinen U, Maaheimo H, Permi P. Structural and Functional Insights Into Lysostaphin-Substrate Interaction. Front Mol Biosci 2018; 5:60. [PMID: 30018958 PMCID: PMC6038053 DOI: 10.3389/fmolb.2018.00060] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 06/12/2018] [Indexed: 11/13/2022] Open
Abstract
Lysostaphin from Staphylococcus simulans and its family enzymes rapidly acquire prominence as the next generation agents in treatment of S. aureus infections. The specificity of lysostaphin is promoted by its C-terminal cell wall targeting domain selectivity toward pentaglycine bridges in S. aureus cell wall. Scission of these cross-links is carried out by its N-terminal catalytic domain, a zinc-dependent endopeptidase. Understanding the determinants affecting the efficiency of catalysis and strength and specificity of interactions lies at the heart of all lysostaphin family enzyme applications. To this end, we have used NMR, SAXS and molecular dynamics simulations to characterize lysostaphin structure and dynamics, to address the inter-domain interaction, the enzyme-substrate interaction as well as the catalytic properties of pentaglycine cleavage in solution. Our NMR structure confirms the recent crystal structure, yet, together with the molecular dynamics simulations, emphasizes the dynamic nature of the loops embracing the catalytic site. We found no evidence for inter-domain interaction, but, interestingly, the SAXS data delineate two preferred conformation subpopulations. Catalytic H329 and H360 were observed to bind a second zinc ion, which reduces lysostaphin pentaglycine cleaving activity. Binding of pentaglycine or its lysine derivatives to the targeting domain was found to be of very low affinity. The pentaglycine interaction site was located to the N-terminal groove of the domain. Notably, the targeting domain binds the peptidoglycan stem peptide Ala-d-γ-Glu-Lys-d-Ala-d-Ala with a much higher, micromolar affinity. Binding site mapping reveals two interaction sites of different affinities on the surface of the domain for this peptide.
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Affiliation(s)
- Helena Tossavainen
- Department of Chemistry, Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland
| | - Vytas Raulinaitis
- Program in Structural Biology and Biophysics, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Linda Kauppinen
- Department of Biological and Environmental Science, University of Jyvaskyla, Jyvaskyla, Finland
| | - Ulla Pentikäinen
- Department of Biological and Environmental Science, University of Jyvaskyla, Jyvaskyla, Finland.,Institute of Biomedicine, University of Turku, Turku, Finland.,Turku Centre for Biotechnology, Turku, Finland
| | - Hannu Maaheimo
- VTT Technical Research Centre of Finland Ltd., Espoo, Finland
| | - Perttu Permi
- Department of Chemistry, Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland.,Department of Biological and Environmental Science, University of Jyvaskyla, Jyvaskyla, Finland
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Bornikoel J, Staiger J, Madlung J, Forchhammer K, Maldener I. LytM factor Alr3353 affects filament morphology and cell-cell communication in the multicellular cyanobacteriumAnabaenasp. PCC 7120. Mol Microbiol 2018; 108:187-203. [DOI: 10.1111/mmi.13929] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2018] [Indexed: 01/16/2023]
Affiliation(s)
- Jan Bornikoel
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Organismic Interactions; University of Tübingen, Auf der Morgenstelle 28; 72076 Tübingen Germany
| | - Julia Staiger
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Organismic Interactions; University of Tübingen, Auf der Morgenstelle 28; 72076 Tübingen Germany
| | - Johannes Madlung
- Proteome Center Tübingen; University of Tübingen, Auf der Morgenstelle 15; 72076 Tübingen Germany
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Organismic Interactions; University of Tübingen, Auf der Morgenstelle 28; 72076 Tübingen Germany
| | - Iris Maldener
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Organismic Interactions; University of Tübingen, Auf der Morgenstelle 28; 72076 Tübingen Germany
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Cherkaoui A, Diene SM, Fischer A, Leo S, François P, Schrenzel J. Transcriptional Modulation of Penicillin-Binding Protein 1b, Outer Membrane Protein P2 and Efflux Pump (AcrAB-TolC) during Heat Stress Is Correlated to Enhanced Bactericidal Action of Imipenem on Non-typeable Haemophilus influenzae. Front Microbiol 2018; 8:2676. [PMID: 29375536 PMCID: PMC5770572 DOI: 10.3389/fmicb.2017.02676] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 12/21/2017] [Indexed: 11/13/2022] Open
Abstract
Objective: The purpose of the present study was to investigate the penicillin binding proteins (PBPs), drug influx and efflux modulations during heat stress and their effects on the bactericidal action of imipenem on non-typeable Haemophilus influenzae (NTHi). Methods: The two NTHi clinical isolates (GE47 and GE88, imipenem MICs by E-test > 32 μg/mL) examined in this study were collected at Geneva University Hospitals. The imipenem killing activity was assessed after incubation of the NTHi strains at either 37 or 42°C for 3 h with increasing concentrations of imipenem. The detection of PBPs was carried out by Bocillin-FL. Global transcriptional changes were monitored by RNA-seq after pre-incubation of bacterial cells at either 37 or 42°C, and the expression levels of relevant target genes were confirmed by qRT-PCR. Results: Quantitation of NTHi viable cells after incubation with 0.25 μg/mL of imipenem for 3 h revealed more than a twofold decrease in GE47 and GE88 viable cells at 42°C as compared to 37°C. Transcriptome analysis showed that under heat stress conditions, there were 141 differentially expressed genes with a | log2(fold change)| > 1, including 67 up-regulated and 74 down-regulated genes. The expression levels of ponB (encoding PBP1b) and acrR (regulator of AcrAB-TolC efflux pump) were significantly increased at 42°C. In contrast, the transcript levels of ompP2 (encoding the outer membrane protein P2) and acrB gene (encoding AcrB) were significantly lower under heat stress condition. Conclusion: This study shows that the transcriptional modulation of ponB, ompP2, acrR, and acrB in the heat stress response is correlated to enhanced antimicrobial effects of imipenem on non-typeable H. influenzae.
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Affiliation(s)
- Abdessalam Cherkaoui
- Bacteriology Laboratory, Division of Laboratory Medicine, Department of Genetics and Laboratory Medicine, Geneva University Hospitals, Geneva, Switzerland
| | - Seydina M Diene
- Genomic Research Laboratory, Division of Infectious Diseases, Geneva University Hospitals, Geneva, Switzerland
| | - Adrien Fischer
- Bacteriology Laboratory, Division of Laboratory Medicine, Department of Genetics and Laboratory Medicine, Geneva University Hospitals, Geneva, Switzerland
| | - Stefano Leo
- Genomic Research Laboratory, Division of Infectious Diseases, Geneva University Hospitals, Geneva, Switzerland
| | - Patrice François
- Genomic Research Laboratory, Division of Infectious Diseases, Geneva University Hospitals, Geneva, Switzerland
| | - Jacques Schrenzel
- Bacteriology Laboratory, Division of Laboratory Medicine, Department of Genetics and Laboratory Medicine, Geneva University Hospitals, Geneva, Switzerland.,Genomic Research Laboratory, Division of Infectious Diseases, Geneva University Hospitals, Geneva, Switzerland
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Tsang MJ, Yakhnina AA, Bernhardt TG. NlpD links cell wall remodeling and outer membrane invagination during cytokinesis in Escherichia coli. PLoS Genet 2017; 13:e1006888. [PMID: 28708841 PMCID: PMC5533458 DOI: 10.1371/journal.pgen.1006888] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 07/28/2017] [Accepted: 06/22/2017] [Indexed: 12/21/2022] Open
Abstract
Cytokinesis in gram-negative bacteria requires the constriction of all three cell envelope layers: the inner membrane (IM), the peptidoglycan (PG) cell wall and the outer membrane (OM). In order to avoid potentially lethal breaches in cell integrity, this dramatic reshaping of the cell surface requires tight coordination of the different envelope remodeling activities of the cytokinetic ring. However, the mechanisms responsible for this coordination remain poorly defined. One of the few characterized regulatory points in the envelope remodeling process is the activation of cell wall hydrolytic enzymes called amidases. These enzymes split cell wall material shared by developing daughter cells to facilitate their eventual separation. In Escherichia coli, amidase activity requires stimulation by one of two partially redundant activators: EnvC, which is associated with the IM, and NlpD, a lipoprotein anchored in the OM. Here, we investigate the regulation of amidase activation by NlpD. Structure-function analysis revealed that the OM localization of NlpD is critical for regulating its amidase activation activity. To identify additional factors involved in the NlpD cell separation pathway, we also developed a genetic screen using a flow cytometry-based enrichment procedure. This strategy allowed us to isolate mutants that form long chains of unseparated cells specifically when the redundant EnvC pathway is inactivated. The screen implicated the Tol-Pal system and YraP in NlpD activation. The Tol-Pal system is thought to promote OM invagination at the division site. YraP is a conserved protein of unknown function that we have identified as a new OM-localized component of the cytokinetic ring. Overall, our results support a model in which OM and PG remodeling events at the division site are coordinated in part through the coupling of NlpD activation with OM invagination.
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Affiliation(s)
- Mary-Jane Tsang
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Anastasiya A. Yakhnina
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Thomas G. Bernhardt
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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Bacterial Lysis through Interference with Peptidoglycan Synthesis Increases Biofilm Formation by Nontypeable Haemophilus influenzae. mSphere 2017; 2:mSphere00329-16. [PMID: 28124027 PMCID: PMC5244263 DOI: 10.1128/msphere.00329-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 12/31/2016] [Indexed: 11/20/2022] Open
Abstract
Most, if not all, bacteria form a biofilm, a multicellular structure that protects them from antimicrobial actions of the host immune system and affords resistance to antibiotics. The latter is especially disturbing with the increase in multiresistant bacterial clones worldwide. Bacterial biofilm formation is a multistep process that starts with surface adhesion, after which attached bacteria divide and give rise to biomass. The actual steps required for Haemophilus influenzae biofilm formation are largely not known. We show that interference with peptidoglycan biosynthesis increases biofilm formation because of the release of bacterial genomic DNA. Subinhibitory concentrations of β-lactam antibiotics, which are often prescribed to treat H. influenzae infections, increase biofilm formation through a similar mechanism. Therefore, when β-lactam antibiotics do not reach their MIC in vivo, they might not only drive selection for β-lactam-resistant clones but also increase biofilm formation and resistance to other antimicrobial compounds. Nontypeable Haemophilus influenzae (NTHi) is an opportunistic pathogen that mainly causes otitis media in children and community-acquired pneumonia or exacerbations of chronic obstructive pulmonary disease in adults. A large variety of studies suggest that biofilm formation by NTHi may be an important step in the pathogenesis of this bacterium. However, the underlying mechanisms involved in this process are poorly elucidated. In this study, we used a transposon mutant library to identify bacterial genes involved in biofilm formation. The growth and biofilm formation of 4,172 transposon mutants were determined, and the involvement of the identified genes in biofilm formation was validated in in vitro experiments. Here, we present experimental data showing that increased bacterial lysis, through interference with peptidoglycan synthesis, results in elevated levels of extracellular DNA, which increased biofilm formation. Interestingly, similar results were obtained with subinhibitory concentrations of β-lactam antibiotics, known to interfere with peptidoglycan synthesis, but such an effect does not appear with other classes of antibiotics. These results indicate that treatment with β-lactam antibiotics, especially for β-lactam-resistant NTHi isolates, might increase resistance to antibiotics by increasing biofilm formation. IMPORTANCE Most, if not all, bacteria form a biofilm, a multicellular structure that protects them from antimicrobial actions of the host immune system and affords resistance to antibiotics. The latter is especially disturbing with the increase in multiresistant bacterial clones worldwide. Bacterial biofilm formation is a multistep process that starts with surface adhesion, after which attached bacteria divide and give rise to biomass. The actual steps required for Haemophilus influenzae biofilm formation are largely not known. We show that interference with peptidoglycan biosynthesis increases biofilm formation because of the release of bacterial genomic DNA. Subinhibitory concentrations of β-lactam antibiotics, which are often prescribed to treat H. influenzae infections, increase biofilm formation through a similar mechanism. Therefore, when β-lactam antibiotics do not reach their MIC in vivo, they might not only drive selection for β-lactam-resistant clones but also increase biofilm formation and resistance to other antimicrobial compounds.
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28
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Pérez-Cruz C, Cañas MA, Giménez R, Badia J, Mercade E, Baldomà L, Aguilera L. Membrane Vesicles Released by a hypervesiculating Escherichia coli Nissle 1917 tolR Mutant Are Highly Heterogeneous and Show Reduced Capacity for Epithelial Cell Interaction and Entry. PLoS One 2016; 11:e0169186. [PMID: 28036403 PMCID: PMC5201253 DOI: 10.1371/journal.pone.0169186] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 12/13/2016] [Indexed: 12/18/2022] Open
Abstract
Membrane vesicles (MVs) produced by Gram-negative bacteria are being explored for novel clinical applications due to their ability to deliver active molecules to distant host cells, where they can exert immunomodulatory properties. MVs released by the probiotic Escherichia coli Nissle 1917 (EcN) are good candidates for testing such applications. However, a drawback for such studies is the low level of MV isolation from in vitro culture supernatants, which may be overcome by the use of mutants in cell envelope proteins that yield a hypervesiculation phenotype. Here, we confirm that a tolR mutation in EcN increases MV production, as determined by protein, LPS and fluorescent lipid measurements. Transmission electron microscopy (TEM) of negatively stained MVs did not reveal significant differences with wild type EcN MVs. Conversely, TEM observation after high-pressure freezing followed by freeze substitution of bacterial samples, together with cryo-TEM observation of plunge-frozen hydrated isolated MVs showed considerable structural heterogeneity in the EcN tolR samples. In addition to common one-bilayer vesicles (OMVs) and the recently described double-bilayer vesicles (O-IMVs), other types of MVs were observed. Time-course experiments of MV uptake in Caco-2 cells using rhodamine- and DiO-labelled MVs evidenced that EcN tolR MVs displayed reduced internalization levels compared to the wild-type MVs. The low number of intracellular MVs was due to a lower cell binding capacity of the tolR-derived MVs, rather than a different entry pathway or mechanism. These findings indicate that heterogeneity of MVs from tolR mutants may have a major impact on vesicle functionality, and point to the need for conducting a detailed structural analysis when MVs from hypervesiculating mutants are to be used for biotechnological applications.
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Affiliation(s)
- Carla Pérez-Cruz
- Secció de Microbiologia, Departament de Biologia, Sanitat i Medi Ambient, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain
| | - María-Alexandra Cañas
- Secció de Bioquímica i Biologia Molecular, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain
- Institut de Biomedicina de la Universitat de Barcelona, Barcelona, Spain
| | - Rosa Giménez
- Secció de Bioquímica i Biologia Molecular, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain
- Institut de Biomedicina de la Universitat de Barcelona, Barcelona, Spain
| | - Josefa Badia
- Secció de Bioquímica i Biologia Molecular, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain
- Institut de Biomedicina de la Universitat de Barcelona, Barcelona, Spain
| | - Elena Mercade
- Secció de Microbiologia, Departament de Biologia, Sanitat i Medi Ambient, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain
| | - Laura Baldomà
- Secció de Bioquímica i Biologia Molecular, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain
- Institut de Biomedicina de la Universitat de Barcelona, Barcelona, Spain
- * E-mail:
| | - Laura Aguilera
- Secció de Bioquímica i Biologia Molecular, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain
- Institut de Biomedicina de la Universitat de Barcelona, Barcelona, Spain
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Identification of EnvC and Its Cognate Amidases as Novel Determinants of Intrinsic Resistance to Cationic Antimicrobial Peptides. Antimicrob Agents Chemother 2016; 60:2222-31. [PMID: 26810659 PMCID: PMC4808223 DOI: 10.1128/aac.02699-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Accepted: 01/20/2016] [Indexed: 11/30/2022] Open
Abstract
Cationic antimicrobial peptides (CAMPs) are an essential part of the innate immune system. Some Gram-negative enteric pathogens, such as Salmonella enterica, show intrinsic resistance to CAMPs. However, the molecular basis of intrinsic resistance is poorly understood, largely due to a lack of information about the genes involved. In this study, using a microarray-based genomic technique, we screened the Keio collection of 3,985 Escherichia coli mutants for altered susceptibility to human neutrophil peptide 1 (HNP-1) and identified envC and zapB as novel genetic determinants of intrinsic CAMP resistance. In CAMP killing assays, an E. coli ΔenvCEc or ΔzapBEc mutant displayed a distinct profile of increased susceptibility to both LL-37 and HNP-1. Both mutants, however, displayed wild-type resistance to polymyxin B and human β-defensin 3 (HBD3), suggesting that the intrinsic resistance mediated by EnvC or ZapB is specific to certain CAMPs. A corresponding Salmonella ΔenvCSe mutant showed similarly increased CAMP susceptibility. The envC mutants of both E. coli and S. enterica displayed increased surface negativity and hydrophobicity, which partly explained the increased CAMP susceptibility. However, the ΔenvCEc mutant, but not the ΔenvCSe mutant, was defective in outer membrane permeability, excluding this defect as a common factor contributing to the increased CAMP susceptibility. Animal experiments showed that the Salmonella ΔenvCSe mutant had attenuated virulence. Taken together, our results indicate that the role of envC in intrinsic CAMP resistance is likely conserved among Gram-negative enteric bacteria, demonstrate the importance of intrinsic CAMP resistance for full virulence of S. enterica, and provide insight into distinct mechanisms of action of CAMPs.
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The Gonococcal NlpD Protein Facilitates Cell Separation by Activating Peptidoglycan Cleavage by AmiC. J Bacteriol 2015; 198:615-22. [PMID: 26574512 DOI: 10.1128/jb.00540-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 11/11/2015] [Indexed: 12/23/2022] Open
Abstract
UNLABELLED Key steps in bacterial cell division are the synthesis and subsequent hydrolysis of septal peptidoglycan (PG), which allow efficient separation of daughter cells. Extensive studies in the Gram-negative, rod-shaped bacterium Escherichia coli have revealed that this hydrolysis is highly regulated spatially and temporally. Neisseria gonorrhoeae is an obligate Gram-negative, diplococcal pathogen and is the only causative agent of the sexually transmitted infection gonorrhea. We investigated how cell separation proceeds in this diplococcal organism. We demonstrated that deletion of the nlpD gene in strain FA1090 leads to poor growth and to an altered colony and cell morphology. An isopropyl-beta-d-galactopyranoside (IPTG)-regulated nlpD complemented construct can restore these defects only when IPTG is supplied in the growth medium. Thin-section transmission electron microscopy (TEM) revealed that the nlpD mutant strain grew in large clumps containing live and dead bacteria, which was consistent with deficient cell separation. Biochemical analyses of purified NlpD protein showed that it was able to bind purified PG. Finally, we showed that, although NlpD has no hydrolase activity itself, NlpD potentiates the hydrolytic activity of AmiC. These results indicate that N. gonorrhoeae NlpD is required for proper cell growth and division through its interactions with the amidase AmiC. IMPORTANCE N. gonorrhoeae is the sole causative agent of the sexually transmitted infection gonorrhea. The incidence of antibiotic-resistant gonococcal infections has risen sharply in recent years, and N. gonorrhoeae has been classified as a "superbug" by the CDC. Since there is a dearth of new antibiotics to combat gonococcal infections, elucidating the essential cellular process of N. gonorrhoeae may point to new targets for antimicrobial therapies. Cell division and separation is one such essential process. We identified and characterized the gonococcal nlpD gene and showed that it is essential for cell separation. In contrast to other pathogenic bacteria, the gonococcal system is streamlined and does not appear to have any redundancies.
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31
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Gaillard ME, Bottero D, Moreno G, Rumbo M, Hozbor D. Strategies and new developments to control pertussis, an actual health problem. Pathog Dis 2015; 73:ftv059. [PMID: 26260328 DOI: 10.1093/femspd/ftv059] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2015] [Indexed: 12/26/2022] Open
Abstract
The aim of this article is to describe the current epidemiological situation of pertussis, as well as different short-term strategies that have been implemented to alleviate this threat. The state of the art of the development of new vaccines that are expected to provide long-lasting immunity against pertussis was also included.
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Affiliation(s)
- María Emilia Gaillard
- Laboratorio VacSal, Instituto de Biotecnología y Biología Molecular (IBBM), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CCT-CONICET La Plata, Calles 50 y 115, 1900, La Plata, Argentina
| | - Daniela Bottero
- Laboratorio VacSal, Instituto de Biotecnología y Biología Molecular (IBBM), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CCT-CONICET La Plata, Calles 50 y 115, 1900, La Plata, Argentina
| | - Griselda Moreno
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), Facultad de Ciencias Exactas, UNLP 47 y 115 (1900) La Plata, Argentina
| | - Martin Rumbo
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), Facultad de Ciencias Exactas, UNLP 47 y 115 (1900) La Plata, Argentina
| | - Daniela Hozbor
- Laboratorio VacSal, Instituto de Biotecnología y Biología Molecular (IBBM), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CCT-CONICET La Plata, Calles 50 y 115, 1900, La Plata, Argentina
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32
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Yakhnina AA, McManus HR, Bernhardt TG. The cell wall amidase AmiB is essential for Pseudomonas aeruginosa cell division, drug resistance and viability. Mol Microbiol 2015; 97:957-73. [PMID: 26032134 DOI: 10.1111/mmi.13077] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2015] [Indexed: 12/17/2022]
Abstract
The physiological function of cell wall amidases has been investigated in several proteobacterial species. In all cases, they have been implicated in the cleavage of cell wall material synthesized by the cytokinetic ring. Although typically non-essential, this activity is critical for daughter cell separation and outer membrane invagination during division. In Escherichia coli, proteins with LytM domains also participate in cell separation by stimulating amidase activity. Here, we investigated the function of amidases and LytM proteins in the opportunistic pathogen Pseudomonas aeruginosa. In agreement with studies in other organisms, (Pa) AmiB and three LytM proteins were found to play crucial roles in P. aeruginosa cell separation, envelope integrity and antibiotic resistance. Importantly, the phenotype of amidase-defective P. aeruginosa cells also differed in informative ways from the E. coli paradigm; (Pa) AmiB was found to be essential for viability and the successful completion of cell constriction. Our results thus reveal a key role for amidase activity in cytokinetic ring contraction. Furthermore, we show that the essential function of (Pa) AmiB can be bypassed in mutants activated for a Cpx-like envelope stress response, suggesting that this signaling system may elicit the repair of division machinery defects in addition to general envelope damage.
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Affiliation(s)
- Anastasiya A Yakhnina
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Heather R McManus
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Thomas G Bernhardt
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, 02115, USA
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