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Shen L, Gao L, Swoboda AR, Ouellette SP. Targeted repression of topA by CRISPRi reveals a critical function for balanced DNA topoisomerase I activity in the Chlamydia trachomatis developmental cycle. mBio 2024; 15:e0258423. [PMID: 38265209 PMCID: PMC10865786 DOI: 10.1128/mbio.02584-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 12/06/2023] [Indexed: 01/25/2024] Open
Abstract
Chlamydia trachomatis is an obligate intracellular bacterium that is responsible for the most prevalent bacterial sexually transmitted infection. Changes in DNA topology in this pathogen have been linked to its pathogenicity-associated developmental cycle. Here, evidence is provided that the balanced activity of DNA topoisomerases contributes to controlling Chlamydia developmental processes. Utilizing catalytically inactivated Cas12 (dCas12)-based clustered regularly interspaced short palindromic repeats interference (CRISPRi) technology, we demonstrate targeted knockdown of chromosomal topA transcription in C. trachomatis without detected toxicity of dCas12. Repression of topA impaired the developmental cycle of C. trachomatis mostly through disruption of its differentiation from a replicative form to an infectious form. Consistent with this, expression of late developmental genes of C. trachomatis was downregulated, while early genes maintained their expression. Importantly, the developmental defect associated with topA knockdown was rescued by overexpressing topA at an appropriate degree and time, directly linking the growth patterns to the levels of topA expression. Interestingly, topA knockdown had effects on DNA gyrase expression, indicating a potential compensatory mechanism for survival to offset TopA deficiency. C. trachomatis with topA knocked down displayed hypersensitivity to moxifloxacin that targets DNA gyrase in comparison with the wild type. These data underscore the requirement of integrated topoisomerase actions to support the essential developmental and transcriptional processes of C. trachomatis.IMPORTANCEWe used genetic and chemical tools to demonstrate the relationship of topoisomerase activities and their obligatory role for the chlamydial developmental cycle. Successfully targeting the essential gene topA with a CRISPRi approach, using dCas12, in C. trachomatis indicates that this method will facilitate the characterization of the essential genome. These findings have an important impact on our understanding of the mechanisms by which well-balanced topoisomerase functions in adaptation of C. trachomatis to unfavorable growth conditions imposed by antibiotics.
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Affiliation(s)
- Li Shen
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Leiqiong Gao
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Abigail R. Swoboda
- Department of Pathology, Microbiology, and Immunology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Scot P. Ouellette
- Department of Pathology, Microbiology, and Immunology, University of Nebraska Medical Center, Omaha, Nebraska, USA
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2
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Shen L, Gao L, Swoboda AR, Ouellette SP. Targeted repression of DNA topoisomerase I by CRISPRi reveals a critical function for it in the Chlamydia trachomatis developmental cycle. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.14.532001. [PMID: 36993624 PMCID: PMC10054935 DOI: 10.1101/2023.03.14.532001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Chlamydia trachomatis is an obligate intracellular bacterium that is responsible for the most prevalent bacterial sexually transmitted infections. Changes in DNA topology in this pathogen have been linked to its pathogenicity-associated developmental cycle. Here, evidence is provided that the balanced activity of DNA topoisomerases (Topos) contributes to Chlamydia developmental processes. Utilizing catalytically inactivated Cas12 (dCas12) based-clustered regularly interspaced short palindromic repeats interference (CRISPRi) technology, we demonstrate targeted knockdown of chromosomal topA transcription in C. trachomatis without detected toxicity of dCas12. Repression of topA impaired the growth of C. trachomatis mostly through disruption of its differentiation from a replicative form to an infectious form. Consistent with this, expression of late developmental genes of C. trachomatis was downregulated while early genes maintained their expression. Importantly, the growth defect associated with topA knockdown was rescued by overexpressing topA at an appropriate degree and time, directly linking the growth patterns to the levels of topA expression. Interestingly, topA knockdown had pleiotropic effects on DNA gyrase expression, indicating a potential compensatory mechanism for survival to offset TopA deficiency. C. trachomatis with topA knocked down displayed hypersensitivity to moxifloxacin that targets DNA gyrase in comparison with the wild type. These data underscore the requirement of integrated topoisomerase actions to support the essential development and transcriptional processes of C. trachomatis.
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Affiliation(s)
- Li Shen
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112
| | - Leiqiong Gao
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112
| | - Abigail R. Swoboda
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Scot P. Ouellette
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
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3
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Lin H, Yang C, Wang W. Imitate to illuminate: labeling of bacterial peptidoglycan with fluorescent and bio-orthogonal stem peptide-mimicking probes. RSC Chem Biol 2022; 3:1198-1208. [PMID: 36320889 PMCID: PMC9533424 DOI: 10.1039/d2cb00086e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 08/01/2022] [Indexed: 11/30/2022] Open
Abstract
Because of its high involvement in antibiotic therapy and the emergence of drug-resistance, the chemical structure and biosynthesis of bacterial peptidoglycan (PGN) have been some of the key topics in bacteriology for several decades. Recent advances in the development of fluorescent or bio-orthogonal stem peptide-mimicking probes for PGN-labeling have rekindled the interest of chemical biologists and microbiologists in this area. The structural designs, bio-orthogonal features and flexible uses of these peptide-based probes allow directly assessing, not only the presence of PGN in different biological systems, but also specific steps in PGN biosynthesis. In this review, we summarize the design rationales, functioning mechanisms, and microbial processes/questions involved in these PGN-targeting probes. Our perspectives on the limitations and future development of these tools are also presented. By imitating the structures of stem peptide, many fluorescent and bio-orthogonal labeling probes have been designed and used in illuminating the peptidoglycan biosynthesis processes.![]()
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Affiliation(s)
- Huibin Lin
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Chaoyong Yang
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
- The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Key Laboratory for Chemical Biology of Fujian Province State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Wei Wang
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
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4
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Greer M, Elnaggar J, Taylor CM, Shen L. Mycoplasma decontamination in Chlamydia trachomatis culture: a curative approach. Pathog Dis 2021; 79:6464140. [PMID: 34918079 DOI: 10.1093/femspd/ftab056] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 12/14/2021] [Indexed: 11/14/2022] Open
Abstract
Mycoplasma contamination of cell culture represents a serious problem in research and decontamination from cell-propagated obligate intracellular bacteria has proven challenging. Here, we presented an optimized protocol to remove Mycoplasma from contaminated Chlamydia trachomatis culture. A stepwise procedure of Mycoplasma removal entails (i) incubation in nonionic detergent containing solution, and (ii) separation of viable chlamydial organisms by fluorescence-activated cell sorting (FACS), followed by subcloning using a focus-forming assay. We also adapted a polymerase chain reaction (PCR) assay using paired universal and Mycoplasma-specific primers, which are distinguishable from the C. trachomatis counterparts, in combination with Sanger sequencing to determine the presence of mycoplasmas' 16S rRNA genes. These integrated approaches allow for full removal of Mycoplasma, as verified by the improved PCR assay, without compromising the capacity of viable C. trachomatis to adapt to new infection in epithelial cells. Some pitfalls during the Mycoplasma decontamination process are discussed.
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Affiliation(s)
- Madison Greer
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Jacob Elnaggar
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Christopher M Taylor
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Li Shen
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
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5
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de la Maza LM, Darville TL, Pal S. Chlamydia trachomatis vaccines for genital infections: where are we and how far is there to go? Expert Rev Vaccines 2021; 20:421-435. [PMID: 33682583 DOI: 10.1080/14760584.2021.1899817] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
INTRODUCTION Chlamydia trachomatis is the most common sexually transmitted bacterial pathogen in the world. Antibiotic treatment does not prevent against reinfection and a vaccine is not yet available. AREAS COVERED We focus the review on the progress made of our understanding of the immunological responses required for a vaccine to elicit protection, and on the antigens, adjuvants, routes of immunization and delivery systems that have been tested in animal models. PubMed and Google Scholar were used to search publication on these topics for the last 5 years and recent Reviews were examined. EXPERT OPINION The first Phase 1 clinical trial of a C. trachomatis vaccine to protect against genital infections was successfully completed. We expect that, in the next five years, additional vaccine clinical trials will be implemented.
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Affiliation(s)
- Luis M de la Maza
- Department of Pathology and Laboratory Medicine Medical Sciences, I, Room D440 University of California, Irvine, California, USA
| | - Toni L Darville
- Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Sukumar Pal
- Department of Pathology and Laboratory Medicine Medical Sciences, I, Room D440 University of California, Irvine, California, USA
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6
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Murray SM, McKay PF. Chlamydia trachomatis: Cell biology, immunology and vaccination. Vaccine 2021; 39:2965-2975. [PMID: 33771390 DOI: 10.1016/j.vaccine.2021.03.043] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 02/06/2023]
Abstract
Chlamydia trachomatis is the causative agent of a highly prevalent sexually transmitted bacterial disease and is associated with a number of severe disease complications. Current therapy options are successful at treating disease, but patients are left without protective immunity and do not benefit the majority asymptomatic patients who do not seek treatment. As such, there is a clear need for a broad acting, protective vaccine that can prevent transmission and protect against symptomatic disease presentation. There are three key elements that underlie successful vaccine development: 1) Chlamydia biology and immune-evasion adaptations, 2) the correlates of protection that prevent disease in natural and experimental infection, 3) reflection upon the evidence provided by previous vaccine attempts. In this review, we give an overview of the unique intra-cellular biology of C. trachomatis and give insight into the dynamic combination of adaptations that allow Chlamydia to subvert host immunity and survive within the cell. We explore the current understanding of chlamydial immunity in animal models and in humans and characterise the key immune correlates of protection against infection. We discuss in detail the specific immune interactions involved in protection, with relevance placed on the CD4+ T lymphocyte and B lymphocyte responses that are key to pathogen clearance. Finally, we provide a timeline of C. trachomatis vaccine research to date and evaluate the successes and failures in development so far. With insight from these three key elements of research, we suggest potential solutions for chlamydial vaccine development and promising avenues for further exploration.
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Affiliation(s)
- Sam M Murray
- Department of Infectious Diseases, Imperial College London, Norfolk Place, London W2 1PG, UK.
| | - Paul F McKay
- Department of Infectious Diseases, Imperial College London, Norfolk Place, London W2 1PG, UK.
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Generation of a novel affibody molecule targeting Chlamydia trachomatis MOMP. Appl Microbiol Biotechnol 2021; 105:1477-1487. [PMID: 33521848 PMCID: PMC7880956 DOI: 10.1007/s00253-021-11128-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 01/07/2021] [Accepted: 01/19/2021] [Indexed: 11/30/2022]
Abstract
Abstract Chlamydia trachomatis (C. trachomatis) is the leading cause of preventable blindness worldwide and the most prevalent cause of bacterial sexually transmitted diseases. At present, there is no available vaccine, and recurrences after antibiotics treatment are substantial problems. Major outer membrane protein (MOMP) accounts for 60% of the outer mass of C. trachomatis, functioning as trimeric porin, and it is highly antigenic. Therefore, MOMP is the most promising candidate for vaccine developing and target therapy of Chlamydia. Affibody, a new class of affinity ligands derived from the Z-domain in the binding region of Staphylococcus aureus protein A, has been the focus of researchers as a viable alternative to antibodies. In this study, the MOMP-targeted affibody molecule (ZMOMP:461) was screened by phage-displayed peptide library. Further, the affinity and specificity were characterized by surface plasmon resonance (SPR) and Western blot. Immunofluorescence assay (IFA) indicated that the MOMP-binding affibody could recognize native MOMP in HeLa229 cells infected C. trachomatis. Immunoprecipitation assay confirmed further that ZMOMP:461 molecule specifically recognizes the epitope on relaxed trimer MOMP. Our findings provide strong evidence that affibody molecule (ZMOMP:461) serves as substitute for MOMP antibody for biological applications and has a great potential for delivering drugs for target therapy. Key points • We screened a novel affibody molecule ZMOMP:461 targeting Chlamydia trachomatis MOMP. • ZMOMP:461 recognizes the recombinant and native MOMP with high affinity and specificity. • ZMOMP:461 could be internalized into live target cells. Supplementary Information The online version contains supplementary material available at 10.1007/s00253-021-11128-x.
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Super-Resolution Fluorescence Microscopy Reveals Clustering Behaviour of Chlamydia pneumoniae's Major Outer Membrane Protein. BIOLOGY 2020; 9:biology9100344. [PMID: 33092039 PMCID: PMC7589890 DOI: 10.3390/biology9100344] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/16/2020] [Accepted: 10/16/2020] [Indexed: 12/20/2022]
Abstract
Chlamydia pneumoniae is a Gram-negative bacterium responsible for a number of human respiratory diseases and linked to some chronic inflammatory diseases. The major outer membrane protein (MOMP) of Chlamydia is a conserved immunologically dominant protein located in the outer membrane, which, together with its surface exposure and abundance, has led to MOMP being the main focus for vaccine and antimicrobial studies in recent decades. MOMP has a major role in the chlamydial outer membrane complex through the formation of intermolecular disulphide bonds, although the exact interactions formed are currently unknown. Here, it is proposed that due to the large number of cysteines available for disulphide bonding, interactions occur between cysteine-rich pockets as opposed to individual residues. Such pockets were identified using a MOMP homology model with a supporting low-resolution (~4 Å) crystal structure. The localisation of MOMP in the E. coli membrane was assessed using direct stochastic optical reconstruction microscopy (dSTORM), which showed a decrease in membrane clustering with cysteine-rich regions containing two mutations. These results indicate that disulphide bond formation was not disrupted by single mutants located in the cysteine-dense regions and was instead compensated by neighbouring cysteines within the pocket in support of this cysteine-rich pocket hypothesis.
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Sigma 54-Regulated Transcription Is Associated with Membrane Reorganization and Type III Secretion Effectors during Conversion to Infectious Forms of Chlamydia trachomatis. mBio 2020; 11:mBio.01725-20. [PMID: 32900805 PMCID: PMC7482065 DOI: 10.1128/mbio.01725-20] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The factors that control the growth and infectious processes for Chlamydia are still poorly understood. This study used recently developed genetic tools to determine the regulon for one of the key transcription factors encoded by Chlamydia, sigma 54. Surrogate and computational analyses provide additional support for the hypothesis that sigma 54 plays a key role in controlling the expression of many components critical to converting and enabling the infectious capability of Chlamydia. These components include those that remodel the membrane for the extracellular environment and incorporation of an arsenal of type III secretion effectors in preparation for infecting new cells. Chlamydia bacteria are obligate intracellular organisms with a phylum-defining biphasic developmental cycle that is intrinsically linked to its ability to cause disease. The progression of the chlamydial developmental cycle is regulated by the temporal expression of genes predominantly controlled by RNA polymerase sigma (σ) factors. Sigma 54 (σ54) is one of three sigma factors encoded by Chlamydia for which the role and regulon are unknown. CtcC is part of a two-component signal transduction system that is requisite for σ54 transcriptional activation. CtcC activation of σ54 requires phosphorylation, which relieves inhibition by the CtcC regulatory domain and enables ATP hydrolysis by the ATPase domain. Prior studies with CtcC homologs in other organisms have shown that expression of the ATPase domain alone can activate σ54 transcription. Biochemical analysis of CtcC ATPase domain supported the idea of ATP hydrolysis occurring in the absence of the regulatory domain, as well as the presence of an active-site residue essential for ATPase activity (E242). Using recently developed genetic approaches in Chlamydia to induce expression of the CtcC ATPase domain, a transcriptional profile was determined that is expected to reflect the σ54 regulon. Computational evaluation revealed that the majority of the differentially expressed genes were preceded by highly conserved σ54 promoter elements. Reporter gene analyses using these putative σ54 promoters reinforced the accuracy of the model of the proposed regulon. Investigation of the gene products included in this regulon supports the idea that σ54 controls expression of genes that are critical for conversion of Chlamydia from replicative reticulate bodies into infectious elementary bodies.
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Gitsels A, Van Lent S, Sanders N, Vanrompay D. Chlamydia: what is on the outside does matter. Crit Rev Microbiol 2020; 46:100-119. [PMID: 32093536 DOI: 10.1080/1040841x.2020.1730300] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This review summarises major highlights on the structural biology of the chlamydial envelope. Chlamydiae are obligate intracellular bacteria, characterised by a unique biphasic developmental cycle. Depending on the stage of their lifecycle, they appear in the form of elementary or reticulate bodies. Since these particles have distinctive functions, it is not surprising that their envelope differs in lipid as well as in protein content. Vice versa, by identifying surface proteins, specific characteristics of the particles such as rigidity or immunogenicity may be deduced. Detailed information on the bacterial membranes will increase our understanding on the host-pathogen interactions chlamydiae employ to survive and grow and might lead to new strategies to battle chlamydial infections.
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Affiliation(s)
- Arlieke Gitsels
- Laboratory of Immunology and Animal Biotechnology, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Sarah Van Lent
- Laboratory of Immunology and Animal Biotechnology, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Niek Sanders
- Laboratory of Gene Therapy, Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Daisy Vanrompay
- Laboratory of Immunology and Animal Biotechnology, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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Proteomic characterisation of the Chlamydia abortus outer membrane complex (COMC) using combined rapid monolithic column liquid chromatography and fast MS/MS scanning. PLoS One 2019; 14:e0224070. [PMID: 31647835 PMCID: PMC6812762 DOI: 10.1371/journal.pone.0224070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 10/01/2019] [Indexed: 11/22/2022] Open
Abstract
Data are presented on the identification and partial characterisation of proteins comprising the chlamydial outer membrane complex (COMC) fraction of Chlamydia abortus (C. abortus)—the aetiological agent of ovine enzootic abortion. Inoculation with the COMC fraction is known to be highly effective in protecting sheep against experimental challenge and its constituent proteins are therefore of interest as potential vaccine candidates. Sodium N-lauroylsarcosine (sarkosyl) insoluble COMC proteins resolved by SDS-PAGE were interrogated by mass spectrometry using combined rapid monolithic column liquid chromatography and fast MS/MS scanning. Downstream database mining of processed tandem MS data revealed the presence of 67 proteins in total, including putative membrane associated proteins (n = 36), such as porins, polymorphic membrane proteins (Pmps), chaperonins and hypothetical membrane proteins, in addition to others (n = 22) that appear more likely to have originated from other subcellular compartments. Electrophoretic mobility data combined with detailed amino acid sequence information derived from secondary fragmentation spectra for 8 Pmps enabled peptides originating from protein cleavage fragments to be mapped to corresponding regions of parent precursor molecules yielding preliminary evidence in support of endogenous post-translational processing of outer membrane proteins in C. abortus. The data presented here will facilitate a deeper understanding of the pathogenesis of C. abortus infection and represent an important step towards the elucidation of the mechanisms of immunoprotection against C. abortus infection and the identification of potential target vaccine candidate antigens.
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Pillonel T, Bertelli C, Aeby S, de Barsy M, Jacquier N, Kebbi-Beghdadi C, Mueller L, Vouga M, Greub G. Sequencing the Obligate Intracellular Rhabdochlamydia helvetica within Its Tick Host Ixodes ricinus to Investigate Their Symbiotic Relationship. Genome Biol Evol 2019; 11:1334-1344. [PMID: 30949677 PMCID: PMC6490308 DOI: 10.1093/gbe/evz072] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/03/2019] [Indexed: 12/15/2022] Open
Abstract
The Rhabdochlamydiaceae family is one of the most widely distributed within the phylum Chlamydiae, but most of its members remain uncultivable. Rhabdochlamydia 16S rRNA was recently reported in more than 2% of 8,534 pools of ticks from Switzerland. Shotgun metagenomics was performed on a pool of five female Ixodes ricinus ticks presenting a high concentration of chlamydial DNA, allowing the assembly of a high-quality draft genome. About 60% of sequence reads originated from a single bacterial population that was named "Candidatus Rhabdochlamydia helvetica" whereas only few thousand reads mapped to the genome of "Candidatus Midichloria mitochondrii," a symbiont normally observed in all I. ricinus females. The 1.8 Mbp genome of R. helvetica is smaller than other Chlamydia-related bacteria. Comparative analyses with other chlamydial genomes identified transposases of the PD-(D/E)XK nuclease family that are unique to this new genome. These transposases show evidence of interphylum horizontal gene transfers between multiple arthropod endosymbionts, including Cardinium spp. (Bacteroidetes) and diverse proteobacteria such as Wolbachia, Rickettsia spp. (Rickettsiales), and Caedimonas varicaedens (Holosporales). Bacterial symbionts were previously suggested to provide B-vitamins to hematophagous hosts. However, incomplete metabolic capacities including for B-vitamin biosynthesis, high bacterial density and limited prevalence suggest that R. helvetica is parasitic rather than symbiotic to its host. The identification of novel Rhabdochlamydia strains in different hosts and their sequencing will help understanding if members of this genus have become highly specialized parasites with reduced genomes, like the Chlamydiaceae, or if they could be pathogenic to humans using ticks as a transmission vector.
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Affiliation(s)
- Trestan Pillonel
- Center for Research on Intracellular Bacteria, Institute of Microbiology, Lausanne University Hospital, University of Lausanne, Switzerland
| | - Claire Bertelli
- Center for Research on Intracellular Bacteria, Institute of Microbiology, Lausanne University Hospital, University of Lausanne, Switzerland
| | - Sébastien Aeby
- Center for Research on Intracellular Bacteria, Institute of Microbiology, Lausanne University Hospital, University of Lausanne, Switzerland
| | - Marie de Barsy
- Center for Research on Intracellular Bacteria, Institute of Microbiology, Lausanne University Hospital, University of Lausanne, Switzerland
| | - Nicolas Jacquier
- Center for Research on Intracellular Bacteria, Institute of Microbiology, Lausanne University Hospital, University of Lausanne, Switzerland
| | - Carole Kebbi-Beghdadi
- Center for Research on Intracellular Bacteria, Institute of Microbiology, Lausanne University Hospital, University of Lausanne, Switzerland
| | - Linda Mueller
- Center for Research on Intracellular Bacteria, Institute of Microbiology, Lausanne University Hospital, University of Lausanne, Switzerland
| | - Manon Vouga
- Center for Research on Intracellular Bacteria, Institute of Microbiology, Lausanne University Hospital, University of Lausanne, Switzerland
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Abstract
The evolutionary separated Gram-negative Chlamydiales show a biphasic life cycle and replicate exclusively within eukaryotic host cells. Members of the genus Chlamydia are responsible for many acute and chronic diseases in humans, and Chlamydia-related bacteria are emerging pathogens. We revisit past efforts to detect cell wall material in Chlamydia and Chlamydia-related bacteria in the context of recent breakthroughs in elucidating the underlying cellular and molecular mechanisms of the chlamydial cell wall biosynthesis. In this review, we also discuss the role of cell wall biosynthesis in chlamydial FtsZ-independent cell division and immune modulation. In the past, penicillin susceptibility of an invisible wall was referred to as the "chlamydial anomaly." In light of new mechanistic insights, chlamydiae may now emerge as model systems to understand how a minimal and modified cell wall biosynthetic machine supports bacterial cell division and how cell wall-targeting beta-lactam antibiotics can also act bacteriostatically rather than bactericidal. On the heels of these discussions, we also delve into the effects of other cell wall antibiotics in individual chlamydial lineages.
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Christensen S, McMahon RM, Martin JL, Huston WM. Life inside and out: making and breaking protein disulfide bonds in Chlamydia. Crit Rev Microbiol 2019; 45:33-50. [PMID: 30663449 DOI: 10.1080/1040841x.2018.1538933] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Disulphide bonds are widely used among all domains of life to provide structural stability to proteins and to regulate enzyme activity. Chlamydia spp. are obligate intracellular bacteria that are especially dependent on the formation and degradation of protein disulphide bonds. Members of the genus Chlamydia have a unique biphasic developmental cycle alternating between two distinct cell types; the extracellular infectious elementary body (EB) and the intracellular replicating reticulate body. The proteins in the envelope of the EB are heavily cross-linked with disulphides and this is known to be critical for this infectious phase. In this review, we provide a comprehensive summary of what is known about the redox state of chlamydial envelope proteins throughout the developmental cycle. We focus especially on the factors responsible for degradation and formation of disulphide bonds in Chlamydia and how this system compares with redox regulation in other organisms. Focussing on the unique biology of Chlamydia enables us to provide important insights into how specialized suites of disulphide bond (Dsb) proteins cater for specific bacterial environments and lifecycles.
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Affiliation(s)
- Signe Christensen
- a Division of Chemistry and Structural Biology , Institute for Molecular Bioscience, University of Queensland , St. Lucia , QLD , Australia.,b Griffith Institute for Drug Discovery, Griffith University , Nathan , QLD , Australia
| | - Róisín M McMahon
- b Griffith Institute for Drug Discovery, Griffith University , Nathan , QLD , Australia
| | - Jennifer L Martin
- b Griffith Institute for Drug Discovery, Griffith University , Nathan , QLD , Australia
| | - Wilhelmina M Huston
- c School of Life Sciences , University of Technology Sydney , Ultimo , NSW , Australia
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15
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Heuson E, Charmantray F, Petit JL, de Berardinis V, Gefflaut T. Enantioselective Synthesis ofd- andl-α-Amino Acids by Enzymatic Transamination Using Glutamine as Smart Amine Donor. Adv Synth Catal 2018. [DOI: 10.1002/adsc.201801278] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Egon Heuson
- Université Clermont Auvergne, CNRS, SIGMA Clermont; ICCF; F-63000 Clermont-Ferrand France
| | - Franck Charmantray
- Université Clermont Auvergne, CNRS, SIGMA Clermont; ICCF; F-63000 Clermont-Ferrand France
| | - Jean-Louis Petit
- Génomique métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Univ Evry; Univ Paris-Saclay; 91057 Evry France
| | - Véronique de Berardinis
- Génomique métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Univ Evry; Univ Paris-Saclay; 91057 Evry France
| | - Thierry Gefflaut
- Université Clermont Auvergne, CNRS, SIGMA Clermont; ICCF; F-63000 Clermont-Ferrand France
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16
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González-Rivera C, Khara P, Awad D, Patel R, Li YG, Bogisch M, Christie PJ. Two pKM101-encoded proteins, the pilus-tip protein TraC and Pep, assemble on the Escherichia coli cell surface as adhesins required for efficient conjugative DNA transfer. Mol Microbiol 2018; 111:96-117. [PMID: 30264928 DOI: 10.1111/mmi.14141] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 09/20/2018] [Accepted: 09/22/2018] [Indexed: 01/10/2023]
Abstract
Mobile genetic elements (MGEs) encode type IV secretion systems (T4SSs) known as conjugation machines for their transmission between bacterial cells. Conjugation machines are composed of an envelope-spanning translocation channel, and those functioning in Gram-negative species additionally elaborate an extracellular pilus to initiate donor-recipient cell contacts. We report that pKM101, a self-transmissible MGE functioning in the Enterobacteriaceae, has evolved a second target cell attachment mechanism. Two pKM101-encoded proteins, the pilus-tip adhesin TraC and a protein termed Pep, are exported to the cell surface where they interact and also form higher order complexes appearing as distinct foci or patches around the cell envelope. Surface-displayed TraC and Pep are required for an efficient conjugative transfer, 'extracellular complementation' potentially involving intercellular protein transfer, and activation of a Pseudomonas aeruginosa type VI secretion system. Both proteins are also required for bacteriophage PRD1 infection. TraC and Pep are exported across the outer membrane by a mechanism potentially involving the β-barrel assembly machinery. The pKM101 T4SS, thus, deploys alternative routing pathways for the delivery of TraC to the pilus tip or both TraC and Pep to the cell surface. We propose that T4SS-encoded, pilus-independent attachment mechanisms maximize the probability of MGE propagation and might be widespread among this translocation superfamily.
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Affiliation(s)
- Christian González-Rivera
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030, USA
| | - Pratick Khara
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030, USA
| | - Dominik Awad
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030, USA
| | - Roosheel Patel
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030, USA
| | - Yang Grace Li
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030, USA
| | | | - Peter J Christie
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030, USA
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17
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Potency of Solithromycin against Fast- and Slow-Growing Chlamydial Organisms. Antimicrob Agents Chemother 2018; 62:AAC.00588-18. [PMID: 29891601 DOI: 10.1128/aac.00588-18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 06/02/2018] [Indexed: 12/16/2022] Open
Abstract
Evidence is provided that solithromycin is a bactericidal against not only fast-growing chlamydial organisms but also those slowed by gamma interferon (IFN-γ) in vitro At sublethal concentrations, Sol impedes homotypic fusion of Chlamydia-containing vacuoles and reduces secretion of the type III secretion (T3S) effector IncA. Sol may therefore represent a potential new clinical treatment for Chlamydia infections. Selective perturbation of the T3S system suggests a novel mode of antibacterial action for Sol that warrants further investigation.
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18
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Bayramova F, Jacquier N, Greub G. Insight in the biology of Chlamydia-related bacteria. Microbes Infect 2017; 20:432-440. [PMID: 29269129 DOI: 10.1016/j.micinf.2017.11.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 11/14/2017] [Accepted: 11/21/2017] [Indexed: 01/21/2023]
Abstract
The Chlamydiales order is composed of obligate intracellular bacteria and includes the Chlamydiaceae family and several family-level lineages called Chlamydia-related bacteria. In this review we will highlight the conserved and distinct biological features between these two groups. We will show how a better characterization of Chlamydia-related bacteria may increase our understanding on the Chlamydiales order evolution, and may help identifying new therapeutic targets to treat chlamydial infections.
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Affiliation(s)
- Firuza Bayramova
- Centre for Research on Intracellular Bacteria, Institute of Microbiology, University Hospital Centre and University of Lausanne, Bugnon 48, 1011 Lausanne, Switzerland
| | - Nicolas Jacquier
- Centre for Research on Intracellular Bacteria, Institute of Microbiology, University Hospital Centre and University of Lausanne, Bugnon 48, 1011 Lausanne, Switzerland
| | - Gilbert Greub
- Centre for Research on Intracellular Bacteria, Institute of Microbiology, University Hospital Centre and University of Lausanne, Bugnon 48, 1011 Lausanne, Switzerland.
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19
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Abstract
Species of Chlamydia are the etiologic agent of endemic blinding trachoma, the leading cause of bacterial sexually transmitted diseases, significant respiratory pathogens, and a zoonotic threat. Their dependence on an intracellular growth niche and their peculiar developmental cycle are major challenges to elucidating their biology and virulence traits. The last decade has seen tremendous advances in our ability to perform a molecular genetic analysis of Chlamydia species. Major achievements include the generation of large collections of mutant strains, now available for forward- and reverse-genetic applications, and the introduction of a system for plasmid-based transformation enabling complementation of mutations; expression of foreign, modified, or reporter genes; and even targeted gene disruptions. This review summarizes the current status of the molecular genetic toolbox for Chlamydia species and highlights new insights into their biology and new challenges in the nascent field of Chlamydia genetics.
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Affiliation(s)
- Barbara S Sixt
- Department for Molecular Genetics and Microbiology, Duke University, Durham, North Carolina 27710; .,Centre de Recherche des Cordeliers, INSERM U1138, Paris 75006, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris 75006, France.,Université Pierre et Marie Curie, Paris 75005, France
| | - Raphael H Valdivia
- Department for Molecular Genetics and Microbiology, Duke University, Durham, North Carolina 27710;
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20
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Update on Chlamydia trachomatis Vaccinology. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2017; 24:CVI.00543-16. [PMID: 28228394 DOI: 10.1128/cvi.00543-16] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Attempts to produce a vaccine to protect against Chlamydia trachomatis-induced trachoma were initiated more than 100 years ago and continued for several decades. Using whole organisms, protective responses were obtained. However, upon exposure to C. trachomatis, disease exacerbation developed in some immunized individuals, precluding the implementation of the vaccine. Evidence of the role of C. trachomatis as a sexually transmitted pathogen started to emerge in the 1960s, and it soon became evident that it can cause acute infections and long-term sequelae in women, men, and newborns. The main focus of this minireview is to summarize recent findings and discuss formulations, including antigens, adjuvants, routes, and delivery systems for immunization, primarily explored in the female mouse model, with the goal of implementing a vaccine against C. trachomatis genital infections.
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21
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Lin X, Li N, Kudo H, Zhang Z, Li J, Wang L, Zhang W, Takechi K, Takano H. Genes Sufficient for Synthesizing Peptidoglycan are Retained in Gymnosperm Genomes, and MurE from Larix gmelinii can Rescue the Albino Phenotype of Arabidopsis MurE Mutation. PLANT & CELL PHYSIOLOGY 2017; 58:587-597. [PMID: 28158764 DOI: 10.1093/pcp/pcx005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 01/10/2017] [Indexed: 05/08/2023]
Abstract
The endosymbiotic theory states that plastids are derived from a single cyanobacterial ancestor that possessed a cell wall. Peptidoglycan (PG), the main component of the bacteria cell wall, gradually degraded during plastid evolution. PG-synthesizing Mur genes have been found to be retained in the genomes of basal streptophyte plants, although many of them have been lost from the genomes of angiosperms. The enzyme encoded by bacterial MurE genes catalyzes the formation of the UDP-N-acetylmuramic acid (UDP-MurNAc) tripeptide in bacterial PG biosynthesis. Knockout of the MurE gene in the moss Physcomitrella patens resulted in defects of chloroplast division, whereas T-DNA-tagged mutants of Arabidopsis thaliana for MurE revealed inhibition of chloroplast development but not of plastid division, suggesting that AtMurE is functionally divergent from the bacterial and moss MurE proteins. Here, we could identify 10 homologs of bacterial Mur genes, including MurE, in the recently sequenced genomes of Picea abies and Pinus taeda, suggesting the retention of the plastid PG system in gymnosperms. To investigate the function of gymnosperm MurE, we isolated an ortholog of MurE from the larch, Larix gmelinii (LgMurE) and confirmed its presence as a single copy per genome, as well as its abundant expression in the leaves of larch seedlings. Analysis with a fusion protein combining green fluorescent protein and LgMurE suggested that it localizes in chloroplasts. Cross-species complementation assay with MurE mutants of A. thaliana and P. patens showed that the expression of LgMurE cDNA completely rescued the albefaction defects in A. thaliana but did not rescue the macrochloroplast phenotype in P. patens. The evolution of plastid PG and the mechanism behind the functional divergence of MurE genes are discussed in the context of information about plant genomes at different evolutionary stages.
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Affiliation(s)
- Xiaofei Lin
- College of Life Sciences, Inner Mongolia University, Hohhot 010021, China
| | - Ningning Li
- College of Life Sciences, Inner Mongolia University, Hohhot 010021, China
| | - Hiromi Kudo
- Graduate School of Science and Technology, Kumamoto University, Kumamoto, 860-8555 Japan
| | - Zhe Zhang
- College of Biological Science, China Agriculture University, Beijing, 100083, China
| | - Jinyu Li
- College of Life Sciences, Inner Mongolia University, Hohhot 010021, China
| | - Li Wang
- College of Life Sciences, Inner Mongolia University, Hohhot 010021, China
| | - Wenbo Zhang
- College of Forestry, Inner Mongolia Agricultural University, Hohhot 010019, China
| | - Katsuaki Takechi
- Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto, 860-8555 Japan
| | - Hiroyoshi Takano
- Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto, 860-8555 Japan
- Institute of Pulsed Power Science, Kumamoto University, Kumamoto, 860-8555 Japan
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22
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Brade H, Brabetz W, Brade L, Hoist O, Löbau S, Lucakova M, Mamat U, Rozalski A, Zych K, Kosma P. Review: Chlamydial lipopolysaccharide. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/096805199700400108] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- H. Brade
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
| | - W. Brabetz
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
| | - L. Brade
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
| | - O. Hoist
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
| | - S. Löbau
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
| | - M. Lucakova
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
| | - U. Mamat
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
| | - A. Rozalski
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
| | - K. Zych
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
| | - P. Kosma
- Institute of Chemistry, University of Agricultural Sciences, Vienna, Austria
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23
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Hanski L, Ausbacher D, Tiirola TM, Strøm MB, Vuorela PM. Amphipathic β2,2-Amino Acid Derivatives Suppress Infectivity and Disrupt the Intracellular Replication Cycle of Chlamydia pneumoniae. PLoS One 2016; 11:e0157306. [PMID: 27280777 PMCID: PMC4900588 DOI: 10.1371/journal.pone.0157306] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 05/29/2016] [Indexed: 12/27/2022] Open
Abstract
We demonstrate in the current work that small cationic antimicrobial β2,2-amino acid derivatives (Mw < 500 Da) are highly potent against Chlamydia pneumoniae at clinical relevant concentrations (< 5 μM, i.e. < 3.4 μg/mL). C. pneumoniae is an atypical respiratory pathogen associated with frequent treatment failures and persistent infections. This gram-negative bacterium has a biphasic life cycle as infectious elementary bodies and proliferating reticulate bodies, and efficient treatment is challenging because of its long and obligate intracellular replication cycle within specialized inclusion vacuoles. Chlamydicidal effect of the β2,2-amino acid derivatives in infected human epithelial cells was confirmed by transmission electron microscopy. Images of infected host cells treated with our lead derivative A2 revealed affected chlamydial inclusion vacuoles 24 hours post infection. Only remnants of elementary and reticulate bodies were detected at later time points. Neither the EM studies nor resazurin-based cell viability assays showed toxic effects on uninfected host cells or cell organelles after A2 treatment. Besides the effects on early intracellular inclusion vacuoles, the ability of these β2,2-amino acid derivatives to suppress Chlamydia pneumoniae infectivity upon treatment of elementary bodies suggested also a direct interaction with bacterial membranes. Synthetic β2,2-amino acid derivatives that target C. pneumoniae represent promising lead molecules for development of antimicrobial agents against this hard-to-treat intracellular pathogen.
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Affiliation(s)
- Leena Hanski
- Pharmaceutical Design and Discovery Research Group, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki (UHEL), Helsinki, Finland
| | - Dominik Ausbacher
- Natural Products and Medicinal Chemistry Research Group, Department of Pharmacy, Faculty of Health Sciences, UiT – The Arctic University of Norway, Tromsø, Norway
| | - Terttu M. Tiirola
- Pharmaceutical Design and Discovery Research Group, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki (UHEL), Helsinki, Finland
| | - Morten B. Strøm
- Natural Products and Medicinal Chemistry Research Group, Department of Pharmacy, Faculty of Health Sciences, UiT – The Arctic University of Norway, Tromsø, Norway
| | - Pia M. Vuorela
- Pharmaceutical Design and Discovery Research Group, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki (UHEL), Helsinki, Finland
- * E-mail:
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24
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Emancipating Chlamydia: Advances in the Genetic Manipulation of a Recalcitrant Intracellular Pathogen. Microbiol Mol Biol Rev 2016; 80:411-27. [PMID: 27030552 DOI: 10.1128/mmbr.00071-15] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Chlamydia species infect millions of individuals worldwide and are important etiological agents of sexually transmitted disease, infertility, and blinding trachoma. Historically, the genetic intractability of this intracellular pathogen has hindered the molecular dissection of virulence factors contributing to its pathogenesis. The obligate intracellular life cycle of Chlamydia and restrictions on the use of antibiotics as selectable markers have impeded the development of molecular tools to genetically manipulate these pathogens. However, recent developments in the field have resulted in significant gains in our ability to alter the genome of Chlamydia, which will expedite the elucidation of virulence mechanisms. In this review, we discuss the challenges affecting the development of molecular genetic tools for Chlamydia and the work that laid the foundation for recent advancements in the genetic analysis of this recalcitrant pathogen.
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25
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Ferrell JC, Fields KA. A working model for the type III secretion mechanism in Chlamydia. Microbes Infect 2015; 18:84-92. [PMID: 26515030 DOI: 10.1016/j.micinf.2015.10.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 10/19/2015] [Accepted: 10/19/2015] [Indexed: 01/09/2023]
Abstract
It has been appreciated for almost 20 years that members of the Chlamydiales possess a virulence-associated type III secretion mechanism. Given the obligate intracellular nature of these bacteria, defining exactly how type III secretion functions to promote pathogenesis has been challenging. We present a working model herein that is based on current evidence.
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Affiliation(s)
- Joshua C Ferrell
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Kenneth A Fields
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY 40536, USA.
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26
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Structural characterization of muropeptides from Chlamydia trachomatis peptidoglycan by mass spectrometry resolves "chlamydial anomaly". Proc Natl Acad Sci U S A 2015; 112:11660-5. [PMID: 26290580 DOI: 10.1073/pnas.1514026112] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The "chlamydial anomaly," first coined by James Moulder, describes the inability of researchers to detect or purify peptidoglycan (PG) from pathogenic Chlamydiae despite genetic and biochemical evidence and antibiotic susceptibility data that suggest its existence. We recently detected PG in Chlamydia trachomatis by a new metabolic cell wall labeling method, however efforts to purify PG from pathogenic Chlamydiae have remained unsuccessful. Pathogenic chlamydial species are known to activate nucleotide-binding oligomerization domain-containing protein 2 (NOD2) innate immune receptors by as yet uncharacterized ligands, which are presumed to be PG fragments (muramyl di- and tripeptides). We used the NOD2-dependent activation of NF-κB by C. trachomatis-infected cell lysates as a biomarker for the presence of PG fragments within specific lysate fractions. We designed a new method of muropeptide isolation consisting of a double filtration step coupled with reverse-phase HPLC fractionation of Chlamydia-infected HeLa cell lysates. Fractions that displayed NOD2 activity were analyzed by electrospray ionization mass spectrometry, confirming the presence of muramyl di- and tripeptides in Chlamydia-infected cell lysate fractions. Moreover, the mass spectrometry data of large muropeptide fragments provided evidence that transpeptidation and transglycosylation reactions occur in pathogenic Chlamydiae. These results reveal the composition of chlamydial PG and disprove the "glycanless peptidoglycan" hypothesis.
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27
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Kebbi-Beghdadi C, Domröse A, Becker E, Cisse OH, Hegemann JH, Greub G. OmpA family proteins and Pmp-like autotransporter: new adhesins of Waddlia chondrophila. Pathog Dis 2015; 73:ftv035. [PMID: 25986220 DOI: 10.1093/femspd/ftv035] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2015] [Indexed: 11/12/2022] Open
Abstract
Waddlia chondrophila is a obligate intracellular bacterium belonging to the Chlamydiales order, a clade that also includes the well-known classical Chlamydia responsible for a number of severe human and animal diseases. Waddlia is an emerging pathogen associated with adverse pregnancy outcomes in humans and abortion in ruminants. Adhesion to the host cell is an essential prerequisite for survival of every strict intracellular bacteria and, in classical Chlamydia, this step is partially mediated by polymorphic outer membrane proteins (Pmps), a family of highly diverse autotransporters that represent about 15% of the bacterial coding capacity. Waddlia chondrophila genome however only encodes one putative Pmp-like protein. Using a proteomic approach, we identified several bacterial proteins potentially implicated in the adhesion process and we characterized their expression during the replication cycle of the bacteria. In addition, we demonstrated that the Waddlia Pmp-like autotransporter as well as OmpA2 and OmpA3, two members of the extended Waddlia OmpA protein family, exhibit adhesive properties on epithelial cells. We hypothesize that the large diversity of the OmpA protein family is linked to the wide host range of these bacteria that are able to enter and multiply in various host cells ranging from protozoa to mammalian and fish cells.
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Affiliation(s)
- Carole Kebbi-Beghdadi
- Center for Research on Intracellular Bacteria (CRIB), Institute of Microbiology, University Hospital Center and University of Lausanne, 1011 Lausanne, Switzerland
| | - Andreas Domröse
- Institut für Funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany
| | - Elisabeth Becker
- Institut für Funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany
| | - Ousmane H Cisse
- Center for Research on Intracellular Bacteria (CRIB), Institute of Microbiology, University Hospital Center and University of Lausanne, 1011 Lausanne, Switzerland
| | - Johannes H Hegemann
- Institut für Funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany
| | - Gilbert Greub
- Center for Research on Intracellular Bacteria (CRIB), Institute of Microbiology, University Hospital Center and University of Lausanne, 1011 Lausanne, Switzerland
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28
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Jacquier N, Viollier PH, Greub G. The role of peptidoglycan in chlamydial cell division: towards resolving the chlamydial anomaly. FEMS Microbiol Rev 2015; 39:262-75. [PMID: 25670734 DOI: 10.1093/femsre/fuv001] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Chlamydiales are obligate intracellular bacteria including some important pathogens causing trachoma, genital tract infections and pneumonia, among others. They share an atypical division mechanism, which is independent of an FtsZ homologue. However, they divide by binary fission, in a process inhibited by penicillin derivatives, causing the formation of an aberrant form of the bacteria, which is able to survive in the presence of the antibiotic. The paradox of penicillin sensitivity of chlamydial cells in the absence of detectable peptidoglycan (PG) was dubbed the chlamydial anomaly, since no PG modified by enzymes (Pbps) that are the usual target of penicillin could be detected in Chlamydiales. We review here the recent advances in this field with the first direct and indirect evidences of PG-like material in both Chlamydiaceae and Chlamydia-related bacteria. Moreover, PG biosynthesis is required for proper localization of the newly described septal proteins RodZ and NlpD. Taken together, these new results set the stage for a better understanding of the role of PG and septal proteins in the division mechanism of Chlamydiales and illuminate the long-standing chlamydial anomaly. Moreover, understanding the chlamydial division mechanism is critical for the development of new antibiotics for the treatment of chlamydial chronic infections.
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Affiliation(s)
- Nicolas Jacquier
- Institute of Microbiology, University Hospital Center and University of Lausanne, CH-1011 Lausanne, Switzerland
| | - Patrick H Viollier
- Department of Microbiology & Molecular Medicine, Institute of Genetics & Genomics in Geneva (iGE3), Faculty of Medicine / CMU, University of Geneva, CH-1211 Geneva 4, Switzerland
| | - Gilbert Greub
- Institute of Microbiology, University Hospital Center and University of Lausanne, CH-1011 Lausanne, Switzerland
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29
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Hua Z, Frohlich KM, Zhang Y, Feng X, Zhang J, Shen L. Andrographolide inhibits intracellular Chlamydia trachomatis multiplication and reduces secretion of proinflammatory mediators produced by human epithelial cells. Pathog Dis 2014; 73:1-11. [PMID: 25854005 DOI: 10.1093/femspd/ftu022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/15/2014] [Indexed: 11/12/2022] Open
Abstract
Chlamydia trachomatis is the most common sexually transmitted bacterial disease worldwide. Untreated C. trachomatis infections may cause inflammation and ultimately damage tissues. Here, we evaluated the ability of Andrographolide (Andro), a natural diterpenoid lactone component of Andrographis paniculata, to inhibit C. trachomatis infection in cultured human cervical epithelial cells. We found that Andro exposure inhibited C. trachomatis growth in a dose- and time-dependent manner. The greatest inhibitory effect was observed when exponentially growing C. trachomatis was exposed to Andro. Electron micrographs demonstrated the accumulation of unusual, structurally deficient chlamydial organisms, correlated with a decrease in levels of OmcB expressed at the late stage of infection. Additionally, Andro significantly reduced the secretion of interleukin6, CXCL8 and interferon-γ-induced protein10 produced by host cells infected with C. trachomatis. These results indicate the efficacy of Andro to perturb C. trachomatis transition from the metabolically active reticulate body to the infectious elementary body and concurrently reduce the production of a proinflammatory mediator by epithelial cells in vitro. Further dissection of Andro's anti-Chlamydia action may provide identification of novel therapeutic targets.
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Affiliation(s)
- Ziyu Hua
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, China, 400014
| | - Kyla M Frohlich
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Yan Zhang
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, China, 400014
| | | | - Jiaxing Zhang
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, China, 400014
| | - Li Shen
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
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30
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Abstract
A defining characteristic of Chlamydia spp. is their developmental cycle characterized by outer membrane transformations of cysteine bonds among cysteine-rich outer membrane proteins. The reduction-oxidation states of host cell compartments were monitored during the developmental cycle using live fluorescence microscopy. Organelle redox states were studied using redox-sensitive green fluorescent protein (roGFP1) expressed in CF15 epithelial cells and targeted to the cytosol, mitochondria, and endoplasmic reticulum (ER). The redox properties of chlamydiae and the inclusion were monitored using roGFP expressed by Chlamydia trachomatis following transformation. Despite the large morphological changes associated with chlamydial infection, redox potentials of the cytosol (Ψcyto [average, −320 mV]), mitochondria (Ψmito [average, −345 mV]), and the ER (ΨER [average, −258 mV]) and their characteristic redox regulatory abilities remained unchanged until the cells died, at which point Ψcyto and Ψmito became more oxidized and ΨER became more reduced. The redox status of the chamydial cytoplasm was measured following transformation and expression of the roGFP biosensor in C. trachomatis throughout the developmental cycle. The periplasmic and outer membrane redox states were assessed by the level of cysteine cross-linking of cysteine-rich envelope proteins. In both cases, the chlamydiae were highly reduced early in the developmental cycle and became oxidized late in the developmental cycle. The production of a late-developmental-stage oxidoreductase/isomerase, DsbJ, may play a key role in the regulation of the oxidoreductive developmental-stage-specific process. Infectious Chlamydia organisms have highly oxidized and cysteine cross-linked membrane proteins that confer environmental stability when outside their host cells. Once these organisms infect a new host cell, the proteins become reduced and remain reduced during the active growth stage. These proteins become oxidized at the end of their growth cycle, wherein infectious organisms are produced and released to the environment. How chlamydiae mediate and regulate this key step in their pathogenesis is unknown. Using biosensors specifically targeted to different compartments within the infected host cell and for the chlamydial organisms themselves, the oxidoreductive states of these compartments were measured during the course of infection. We found that the host cell redox states are not changed by infection with C. trachomatis, whereas the state of the chlamydial organisms remains reduced during infection until the late developmental stages, wherein the organisms’ cytosol and periplasm become oxidized and they acquire environmental resistance and infectivity.
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Aistleitner K, Anrather D, Schott T, Klose J, Bright M, Ammerer G, Horn M. Conserved features and major differences in the outer membrane protein composition of chlamydiae. Environ Microbiol 2014; 17:1397-413. [DOI: 10.1111/1462-2920.12621] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 09/06/2014] [Indexed: 12/28/2022]
Affiliation(s)
- Karin Aistleitner
- Department of Microbiology and Ecosystem Science University of Vienna Vienna Austria
| | - Dorothea Anrather
- Department of Mass Spectrometry Facility Max F. Perutz Laboratories University of Vienna Vienna Austria
| | - Thomas Schott
- Department of Microbiology and Ecosystem Science University of Vienna Vienna Austria
| | - Julia Klose
- Department of Limnology and Oceanography University of Vienna Vienna Austria
| | - Monika Bright
- Department of Limnology and Oceanography University of Vienna Vienna Austria
| | - Gustav Ammerer
- Department of Biochemistry and Cell Biology Max F. Perutz Laboratories University of Vienna Vienna Austria
| | - Matthias Horn
- Department of Microbiology and Ecosystem Science University of Vienna Vienna Austria
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Discovery of chlamydial peptidoglycan reveals bacteria with murein sacculi but without FtsZ. Nat Commun 2014; 4:2856. [PMID: 24292151 PMCID: PMC3847603 DOI: 10.1038/ncomms3856] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 11/01/2013] [Indexed: 11/18/2022] Open
Abstract
Chlamydiae are important pathogens and symbionts, with unique cell biology features. They lack the cell-division protein FtsZ, which functions in maintaining cell shape and orchestrating cell division in almost all other bacteria. In addition, the existence of peptidoglycan (PG) in chlamydial cell envelopes has been highly controversial. Using electron cryotomography, mass spectrometry and fluorescent labeling dyes, here we show that some environmental chlamydiae have cell-wall sacculi consisting of an unusual PG type. Treatment with fosfomycin (a PG synthesis inhibitor) leads to lower infection rates and aberrant cell shapes, suggesting that PG synthesis is crucial for the chlamydial life cycle. Our findings demonstrate for the first time the presence of PG in a member of the Chlamydiae. They also present a unique example of a bacterium with a PG sacculus but without FtsZ, challenging the current hypothesis that it is the absence of a cell wall that renders FtsZ non-essential.
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Frohlich KM, Hua Z, Quayle AJ, Wang J, Lewis ME, Chou CW, Luo M, Buckner LR, Shen L. Membrane vesicle production by Chlamydia trachomatis as an adaptive response. Front Cell Infect Microbiol 2014; 4:73. [PMID: 24959424 PMCID: PMC4050530 DOI: 10.3389/fcimb.2014.00073] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 05/19/2014] [Indexed: 01/08/2023] Open
Abstract
Bacteria have evolved specific adaptive responses to cope with changing environments. These adaptations include stress response phenotypes with dynamic modifications of the bacterial cell envelope and generation of membrane vesicles (MVs). The obligate intracellular bacterium, Chlamydia trachomatis, typically has a biphasic lifestyle, but can enter into an altered growth state typified by morphologically aberrant chlamydial forms, termed persistent growth forms, when induced by stress in vitro. How C. trachomatis can adapt to a persistent growth state in host epithelial cells in vivo is not well understood, but is an important question, since it extends the host-bacterial relationship in vitro and has thus been indicated as a survival mechanism in chronic chlamydial infections. Here, we review recent findings on the mechanistic aspects of bacterial adaptation to stress with a focus on how C. trachomatis remodels its envelope, produces MVs, and the potential important consequences of MV production with respect to host-pathogen interactions. Emerging data suggest that the generation of MVs may be an important mechanism for C. trachomatis intracellular survival of stress, and thus may aid in the establishment of a chronic infection in human genital epithelial cells.
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Affiliation(s)
- Kyla M Frohlich
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center New Orleans, LA, USA
| | - Ziyu Hua
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center New Orleans, LA, USA ; Department of Neonatology, Ministry of Education Key Laboratory of Child Development and Disorder, The Children's Hospital, Chongqing Medical University Chongqing, China
| | - Alison J Quayle
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center New Orleans, LA, USA
| | - Jin Wang
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center New Orleans, LA, USA
| | - Maria E Lewis
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center New Orleans, LA, USA
| | - Chau-wen Chou
- Department of Chemistry, University of Georgia Athens, GA, USA
| | - Miao Luo
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center New Orleans, LA, USA
| | - Lyndsey R Buckner
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center New Orleans, LA, USA
| | - Li Shen
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center New Orleans, LA, USA
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Bachmann NL, Polkinghorne A, Timms P. Chlamydia genomics: providing novel insights into chlamydial biology. Trends Microbiol 2014; 22:464-72. [PMID: 24882432 DOI: 10.1016/j.tim.2014.04.013] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 04/18/2014] [Accepted: 04/28/2014] [Indexed: 12/12/2022]
Abstract
Chlamydiaceae are obligate intracellular pathogens that have successfully evolved to colonize a diverse range of hosts. There are currently 11 described species of Chlamydia, most of which have a significant impact on the health of humans or animals. Expanding chlamydial genome sequence information has revolutionized our understanding of chlamydial biology, including aspects of their unique lifecycle, host-pathogen interactions, and genetic differences between Chlamydia strains associated with different host and tissue tropisms. This review summarizes the major highlights of chlamydial genomics and reflects on the considerable impact these have had on understanding the biology of chlamydial pathogens and the changing nature of genomics tools in the 'post-genomics' era.
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Affiliation(s)
- Nathan L Bachmann
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland 4558, Australia
| | - Adam Polkinghorne
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland 4558, Australia
| | - Peter Timms
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland 4558, Australia.
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Hanski L, Vuorela PM. Recent advances in technologies for developing drugs againstChlamydia pneumoniae. Expert Opin Drug Discov 2014; 9:791-802. [DOI: 10.1517/17460441.2014.915309] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Lienard J, Croxatto A, Gervaix A, Posfay-Barbe K, Baud D, Kebbi-Beghdadi C, Greub G. Undressing of Waddlia chondrophila to enrich its outer membrane proteins to develop a new species-specific ELISA. New Microbes New Infect 2014; 2:13-24. [PMID: 25356333 PMCID: PMC4184618 DOI: 10.1002/2052-2975.26] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 11/16/2013] [Accepted: 11/22/2013] [Indexed: 12/02/2022] Open
Abstract
Waddlia chondrophila, an obligate intracellular bacterium of the Chlamydiales order, is considered as an agent of bovine abortion and a likely cause of miscarriage in humans. Its role in respiratory diseases was questioned after the detection of its DNA in clinical samples taken from patients suffering from pneumonia or bronchiolitis. To better define the role of Waddlia in both miscarriage and pneumonia, a tool allowing large-scale serological investigations of Waddlia seropositivity is needed. Therefore, enriched outer membrane proteins of W. chondrophila were used as antigens to develop a specific ELISA. After thorough analytical optimization, the ELISA was validated by comparison with micro-immunofluorescence and it showed a sensitivity above 85% with 100% specificity. The ELISA was subsequently applied to human sera to specify the role of W. chondrophila in pneumonia. Overall, 3.6% of children showed antibody reactivity against W. chondrophila but no significant difference was observed between children with and without pneumonia. Proteomic analyses were then performed using mass spectrometry, highlighting members of the outer membrane protein family as the dominant proteins. The major Waddlia putative immunogenic proteins were identified by immunoblot using positive and negative human sera. The new ELISA represents an efficient tool with high throughput applications. Although no association with pneumonia and Waddlia seropositivity was observed, this ELISA could be used to specify the role of W. chondrophila in miscarriage and in other diseases.
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Affiliation(s)
- J Lienard
- Center for Research on Intracellular Bacteria, Lausanne University Hospital and University of Lausanne Lausanne
| | - A Croxatto
- Center for Research on Intracellular Bacteria, Lausanne University Hospital and University of Lausanne Lausanne
| | - A Gervaix
- Children's Hospital of Geneva, University Hospitals of Geneva and Medical School of the University of Geneva Switzerland
| | - K Posfay-Barbe
- Children's Hospital of Geneva, University Hospitals of Geneva and Medical School of the University of Geneva Switzerland
| | - D Baud
- Center for Research on Intracellular Bacteria, Lausanne University Hospital and University of Lausanne Lausanne ; St Mary's Hospital London, United Kingdom
| | - C Kebbi-Beghdadi
- Center for Research on Intracellular Bacteria, Lausanne University Hospital and University of Lausanne Lausanne
| | - G Greub
- Center for Research on Intracellular Bacteria, Lausanne University Hospital and University of Lausanne Lausanne
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Liechti GW, Kuru E, Hall E, Kalinda A, Brun YV, VanNieuwenhze M, Maurelli AT. A new metabolic cell-wall labelling method reveals peptidoglycan in Chlamydia trachomatis. Nature 2013; 506:507-10. [PMID: 24336210 PMCID: PMC3997218 DOI: 10.1038/nature12892] [Citation(s) in RCA: 253] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 11/21/2013] [Indexed: 12/16/2022]
Abstract
Peptidoglycan (PG), an essential structure in the cell walls of the vast majority of bacteria, is critical for division and maintaining cell shape and hydrostatic pressure. Bacteria comprising the Chlamydiales were thought to be one of the few exceptions. Chlamydia harbour genes for PG biosynthesis and exhibit susceptibility to 'anti-PG' antibiotics, yet attempts to detect PG in any chlamydial species have proven unsuccessful (the 'chlamydial anomaly'). We used a novel approach to metabolically label chlamydial PG using d-amino acid dipeptide probes and click chemistry. Replicating Chlamydia trachomatis were labelled with these probes throughout their biphasic developmental life cycle, and the results of differential probe incorporation experiments conducted in the presence of ampicillin are consistent with the presence of chlamydial PG-modifying enzymes. These findings culminate 50 years of speculation and debate concerning the chlamydial anomaly and are the strongest evidence so far that chlamydial species possess functional PG.
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Affiliation(s)
- G W Liechti
- 1] Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814-4799, USA [2]
| | - E Kuru
- 1] Interdisciplinary Biochemistry Program, Indiana University, Bloomington, Indiana 47405, USA [2]
| | - E Hall
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA
| | - A Kalinda
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA
| | - Y V Brun
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
| | - M VanNieuwenhze
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA
| | - A T Maurelli
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814-4799, USA
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de Barsy M, Greub G. Waddlia chondrophila: from biology to pathogenicity. Microbes Infect 2013; 15:1033-41. [DOI: 10.1016/j.micinf.2013.09.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 09/02/2013] [Accepted: 09/02/2013] [Indexed: 10/26/2022]
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Sixt BS, Siegl A, Müller C, Watzka M, Wultsch A, Tziotis D, Montanaro J, Richter A, Schmitt-Kopplin P, Horn M. Metabolic features of Protochlamydia amoebophila elementary bodies--a link between activity and infectivity in Chlamydiae. PLoS Pathog 2013; 9:e1003553. [PMID: 23950718 PMCID: PMC3738481 DOI: 10.1371/journal.ppat.1003553] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 06/28/2013] [Indexed: 01/07/2023] Open
Abstract
The Chlamydiae are a highly successful group of obligate intracellular bacteria, whose members are remarkably diverse, ranging from major pathogens of humans and animals to symbionts of ubiquitous protozoa. While their infective developmental stage, the elementary body (EB), has long been accepted to be completely metabolically inert, it has recently been shown to sustain some activities, including uptake of amino acids and protein biosynthesis. In the current study, we performed an in-depth characterization of the metabolic capabilities of EBs of the amoeba symbiont Protochlamydia amoebophila. A combined metabolomics approach, including fluorescence microscopy-based assays, isotope-ratio mass spectrometry (IRMS), ion cyclotron resonance Fourier transform mass spectrometry (ICR/FT-MS), and ultra-performance liquid chromatography mass spectrometry (UPLC-MS) was conducted, with a particular focus on the central carbon metabolism. In addition, the effect of nutrient deprivation on chlamydial infectivity was analyzed. Our investigations revealed that host-free P. amoebophila EBs maintain respiratory activity and metabolize D-glucose, including substrate uptake as well as host-free synthesis of labeled metabolites and release of labeled CO2 from 13C-labeled D-glucose. The pentose phosphate pathway was identified as major route of D-glucose catabolism and host-independent activity of the tricarboxylic acid (TCA) cycle was observed. Our data strongly suggest anabolic reactions in P. amoebophila EBs and demonstrate that under the applied conditions D-glucose availability is essential to sustain metabolic activity. Replacement of this substrate by L-glucose, a non-metabolizable sugar, led to a rapid decline in the number of infectious particles. Likewise, infectivity of Chlamydia trachomatis, a major human pathogen, also declined more rapidly in the absence of nutrients. Collectively, these findings demonstrate that D-glucose is utilized by P. amoebophila EBs and provide evidence that metabolic activity in the extracellular stage of chlamydiae is of major biological relevance as it is a critical factor affecting maintenance of infectivity. The Chlamydiae are a group of bacteria that strictly rely on eukaryotic host cells as a niche for intracellular growth. This group includes major pathogens of humans and animals as well as symbionts of protists. Unlike most other bacteria, chlamydiae alternate between two distinct developmental stages. Here we provide novel insights into the infective stage, the elementary body (EB), which has been described almost a century ago and is commonly referred to as an inert spore-like particle. Our analyses of EBs of the amoeba symbiont Protochlamydia amoebophila provide a detailed overview of their metabolism outside of, and independent from, their natural host cells. We demonstrated that these EBs are capable of respiration and are active in the major routes of central carbon metabolism, including glucose import, biosynthetic reactions, and catabolism for energy generation. Glucose starvation resulted in a rapid decline of metabolic activity in P. amoebophila EBs and a concomitant decrease in their potential to infect new host cells. The human pathogen Chlamydia trachomatis was also dependent on nutrient availability for extracellular survival. The extent of metabolic activity in chlamydial EBs and its consequences for infectivity challenge long-standing textbook knowledge and demonstrate that the infective stage is far more dependent on its environment than previously recognized.
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Affiliation(s)
- Barbara S. Sixt
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Alexander Siegl
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Constanze Müller
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München, Neuherberg, Germany
| | - Margarete Watzka
- Division of Terrestrial Ecosystem Research, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Anna Wultsch
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Dimitrios Tziotis
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München, Neuherberg, Germany
| | - Jacqueline Montanaro
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Andreas Richter
- Division of Terrestrial Ecosystem Research, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | | | - Matthias Horn
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
- * E-mail:
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Bastidas RJ, Elwell CA, Engel JN, Valdivia RH. Chlamydial intracellular survival strategies. Cold Spring Harb Perspect Med 2013; 3:a010256. [PMID: 23637308 DOI: 10.1101/cshperspect.a010256] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Chlamydia trachomatis is the most common sexually transmitted bacterial pathogen and the causative agent of blinding trachoma. Although Chlamydia is protected from humoral immune responses by residing within remodeled intracellular vacuoles, it still must contend with multilayered intracellular innate immune defenses deployed by its host while scavenging for nutrients. Here we provide an overview of Chlamydia biology and highlight recent findings detailing how this vacuole-bound pathogen manipulates host-cellular functions to invade host cells and maintain a replicative niche.
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Affiliation(s)
- Robert J Bastidas
- Department of Molecular Genetics and Microbiology, Center for Microbial Pathogenesis, Duke University Medical Center, Durham, NC 27710, USA
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Linkage between Anaplasma marginale outer membrane proteins enhances immunogenicity but is not required for protection from challenge. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2013; 20:651-6. [PMID: 23446216 DOI: 10.1128/cvi.00600-12] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The prevention of bacterial infections via immunization presents particular challenges. While outer membrane extracts are often protective, they are difficult and expensive to isolate and standardize and thus are often impractical for development and implementation in vaccination programs. In contrast, individual proteins, which are easily adapted for use in subunit vaccines, tend to be poorly protective. Consequently, identification of the specific characteristics of outer membrane-based immunogens, in terms of the antigen contents and contexts that are required for protective immunity, represents a major gap in the knowledge needed for bacterial vaccine development. Using as a model Anaplasma marginale, a persistent tick-borne bacterial pathogen of cattle, we tested two sets of immunogens to determine whether membrane context affected immunogenicity and the capacity to induce protection. The first immunogen was composed of a complex of outer membrane proteins linked by covalent bonds and known to be protective. The second immunogen was derived directly from the first one, but the proteins were individualized rather than linked. The antibody response induced by the linked immunogen was much greater than that induced by the unlinked immunogen. However, both immunogens induced protective immunity and an anamnestic response. These findings suggest that individual proteins or combinations of proteins can be successfully tested for the ability to induce protective immunity with less regard for overall membrane context. Once protective antigens are identified, immunogenicity could be enhanced by cross-linking to allow a reduced immunogen dose or fewer booster vaccinations.
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Aistleitner K, Heinz C, Hörmann A, Heinz E, Montanaro J, Schulz F, Maier E, Pichler P, Benz R, Horn M. Identification and characterization of a novel porin family highlights a major difference in the outer membrane of chlamydial symbionts and pathogens. PLoS One 2013; 8:e55010. [PMID: 23383036 PMCID: PMC3561449 DOI: 10.1371/journal.pone.0055010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 12/18/2012] [Indexed: 11/24/2022] Open
Abstract
The Chlamydiae constitute an evolutionary well separated group of intracellular bacteria comprising important pathogens of humans as well as symbionts of protozoa. The amoeba symbiont Protochlamydia amoebophila lacks a homologue of the most abundant outer membrane protein of the Chlamydiaceae, the major outer membrane protein MOMP, highlighting a major difference between environmental chlamydiae and their pathogenic counterparts. We recently identified a novel family of putative porins encoded in the genome of P. amoebophila by in silico analysis. Two of these Protochlamydiaouter membrane proteins, PomS (pc1489) and PomT (pc1077), are highly abundant in outer membrane preparations of this organism. Here we show that all four members of this putative porin family are toxic when expressed in the heterologous host Escherichia coli. Immunofluorescence analysis using antibodies against heterologously expressed PomT and PomS purified directly from elementary bodies, respectively, demonstrated the location of both proteins in the outer membrane of P. amoebophila. The location of the most abundant protein PomS was further confirmed by immuno-transmission electron microscopy. We could show that pomS is transcribed, and the corresponding protein is present in the outer membrane throughout the complete developmental cycle, suggesting an essential role for P. amoebophila. Lipid bilayer measurements demonstrated that PomS functions as a porin with anion-selectivity and a pore size similar to the Chlamydiaceae MOMP. Taken together, our results suggest that PomS, possibly in concert with PomT and other members of this porin family, is the functional equivalent of MOMP in P. amoebophila. This work contributes to our understanding of the adaptations of symbiotic and pathogenic chlamydiae to their different eukaryotic hosts.
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Affiliation(s)
- Karin Aistleitner
- Department of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Christian Heinz
- Department of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Alexandra Hörmann
- Department of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Eva Heinz
- Department of Microbial Ecology, University of Vienna, Vienna, Austria
| | | | - Frederik Schulz
- Department of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Elke Maier
- Rudolf-Virchow-Center, Deutsche Forschungsgemeinschaft - Research Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Peter Pichler
- Christian Doppler Laboratory for Mass Spectrometry, Vienna, Austria
| | - Roland Benz
- Rudolf-Virchow-Center, Deutsche Forschungsgemeinschaft - Research Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
- School of Engineering and Science, Jacobs University Bremen, Bremen, Germany
| | - Matthias Horn
- Department of Microbial Ecology, University of Vienna, Vienna, Austria
- * E-mail:
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Piasecki T, Chrząstek K, Wieliczko A. Detection and identification of Chlamydophila psittaci in asymptomatic parrots in Poland. BMC Vet Res 2012. [PMID: 23206592 PMCID: PMC3538658 DOI: 10.1186/1746-6148-8-233] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Background Psittacosis, an avian disease caused by Chlamydophila psittaci, can manifest as an acute, protracted, or chronic illness, but can also be asymptomatic. C. psittaci can persist in the host for months to years, often without causing obvious illness, and therefore poses a threat for zoonotic outbreak. We investigated the prevalence of C. psittaci from 156 tracheal swab samples from 34 different species of parrots in Poland, and determined the genotype of strains from the positive samples. Results An overall prevalence of 10.3% was observed using two different PCR assays, both providing similar results. Thirteen of the PCR-positive samples were genotype A, two were genotype B, and one could not be classified. Conclusions These results indicate widespread dissemination of C. psittaci in Polish psittacine populations, without any clinical signs of chlamydiosis, and hence could pose a zoonotic hazard. PCR screening provided a definitive diagnosis of psittacosis, and subsequent ompA gene analysis could be helpful for better understanding the epidemiology of the C. psittaci genotypes. To the best of our knowledge, this is the first report of the incidence of C. psittaci in parrots in Poland.
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Affiliation(s)
- Tomasz Piasecki
- Department of Epizootiology and Clinic of Bird and Exotic Animals, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, pl, Grunwadzki 45, Wrocław, 50-366, Poland.
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Beeckman DS, De Puysseleyr L, De Puysseleyr K, Vanrompay D. Chlamydial biology and its associated virulence blockers. Crit Rev Microbiol 2012; 40:313-28. [PMID: 23134414 DOI: 10.3109/1040841x.2012.726210] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Chlamydiales are obligate intracellular parasites of eukaryotic cells. They can be distinguished from other Gram-negative bacteria through their characteristic developmental cycle, in addition to special biochemical and physical adaptations to subvert the eukaryotic host cell. The host spectrum includes humans and other mammals, fish, birds, reptiles, insects and even amoeba, causing a plethora of diseases. The first part of this review focuses on the specific chlamydial infection biology and metabolism. As resistance to classical antibiotics is emerging among Chlamydiae as well, the second part elaborates on specific compounds and tools to block chlamydial virulence traits, such as adhesion and internalization, Type III secretion and modulation of gene expression.
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Affiliation(s)
- Delphine S Beeckman
- Department of Molecular Biotechnology, Faculty of Bioscience Engineering, Ghent University , Coupure Links 653, B-9000 Ghent , Belgium
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Invasion of eukaryotic cells by Legionella pneumophila: A common strategy for all hosts? Can J Infect Dis 2012; 8:139-46. [PMID: 22514486 DOI: 10.1155/1997/571250] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Legionella pneumophila is an environmental micro-organism capable of producing an acute lobar pneumonia, commonly referred to as Legionnaires' disease, in susceptible humans. Legionellae are ubiquitous in aquatic environments, where they survive in biofilms or intracellularly in various protozoans. Susceptible humans become infected by breathing aerosols laden with the bacteria. The target cell for human infection is the alveolar macrophage, in which the bacteria abrogate phagolysosomal fusion. The remarkable ability of L pneumophila to infect a wide range of eukaryotic cells suggests a common strategy that exploits very fundamental cellular processes. The bacteria enter host cells via coiling phagocytosis and quickly subvert organelle trafficking events, leading to formation of a replicative phagosome in which the bacteria multiply. Vegetative growth continues for 8 to 10 h, after which the bacteria develop into a short, highly motile form called the 'mature form'. The mature form exhibits a thickening of the cell wall, stains red with the Gimenez stain, and is between 10 and 100 times more infectious than agar-grown bacteria. Following host cell lysis, the released bacteria infect other host cells, in which the mature form differentiates into a Gimenez-negative vegetative form, and the cycle begins anew. Virulence of L pneumophila is considered to be multifactorial, and there is growing evidence for both stage specific and sequential gene expression. Thus, L pneumophila may be a good model system for dissecting events associated with the host-parasite interactions.
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Isolation of Chlamydia trachomatis and membrane vesicles derived from host and bacteria. J Microbiol Methods 2012; 91:222-30. [PMID: 22960504 DOI: 10.1016/j.mimet.2012.08.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 08/21/2012] [Accepted: 08/24/2012] [Indexed: 02/06/2023]
Abstract
The study of intracellular bacteria and nanometer-size membrane vesicles within infected host cells poses an important challenge as it is difficult to identify each distinct population in the context of the complex populations generated from active host-pathogen interactions. Here, suspension cultures of L929 cells infected with the prevalent obligate intracellular bacterium Chlamydia trachomatis strain F/Cal-IC-13 are utilized for the large scale preparation and isolation of natural membrane vesicles and bacterial forms. Cell lysis with nitrogen cavitation in combination with differential centrifugation, OptiPrep™ density gradient separation, and immunoenrichment using anti-chlamydial lipopolysaccharide antibodies and MagnaBind beads allows for the isolation of both productive and persistent bacterial forms, as well as membrane vesicles derived from the host and pathogen. We have evaluated these populations by electron microscopy and Western blot analysis for identification of biomarkers. In addition, purified persistent forms of C. trachomatis induced by ampicillin display adenosine-5'-triphosphate (ATP) transport activity, suggesting that ampicillin-induced persistent C. trachomatis organisms, at least in part, rely upon host ATP as an energy source. Importantly, several chlamydial cytotoxic and/or secreted proteins are demonstrated to be associated with these vesicles, supporting the idea that membrane vesicles are generated by Chlamydia as a means of carrying and delivering virulence factors necessary for pathogenesis. The ability to produce large-scale infections and generate distinct bacteria and host-derived populations for biochemical analysis, while reducing the burdens of time and cost have implications in all areas of chlamydiology. These protocols can be applied to other strains of C. trachomatis or other intracellular bacteria.
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Differential effects of DNA supercoiling on Chlamydia early promoters correlate with expression patterns in midcycle. J Bacteriol 2012; 194:3109-15. [PMID: 22505684 DOI: 10.1128/jb.00242-12] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Changes in DNA supercoiling levels during the chlamydial developmental cycle have been proposed as a global mechanism to upregulate midcycle genes, but the effects on early genes are not known. We examined the promoters for 10 Chlamydia trachomatis early genes and found that they could be separated into two subsets based on their responses to DNA supercoiling in vitro. Furthermore, the type of supercoiling response correlated with the in vivo expression pattern for each early gene. One subset of seven early genes had promoters that were transcribed in a supercoiling-insensitive manner over the physiologic range of supercoiling levels that have been measured in Chlamydia. In vivo transcripts for these genes were detected at similar levels during early-stage and midstage times. In contrast, a second subset, represented in our study by three early genes, had supercoiling-dependent promoters that were transcribed at higher levels from more-supercoiled templates, which is the response observed for midcycle genes. Genes in this subset were expressed at higher levels at midstage times than at early times in vivo. We propose that this second subset represents a novel class of chlamydial developmental genes with features of both early and midcycle genes. We hypothesize that expression of these supercoiling-dependent early genes is upregulated by increased chlamydial supercoiling levels in midcycle via their supercoiling-responsive promoters in a manner similar to that for midcycle genes. Thus, we propose that DNA supercoiling is utilized in Chlamydia as a general mechanism to regulate genes in the midstage of the developmental cycle and not just midcycle genes.
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Patin D, Bostock J, Chopra I, Mengin-Lecreulx D, Blanot D. Biochemical characterisation of the chlamydial MurF ligase, and possible sequence of the chlamydial peptidoglycan pentapeptide stem. Arch Microbiol 2012; 194:505-12. [DOI: 10.1007/s00203-011-0784-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 12/01/2011] [Accepted: 12/09/2011] [Indexed: 10/14/2022]
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Disulfide bonding within components of the Chlamydia type III secretion apparatus correlates with development. J Bacteriol 2011; 193:6950-9. [PMID: 22001510 DOI: 10.1128/jb.05163-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chlamydia spp. exhibit a unique biphasic developmental cycle whereby infectious elementary bodies (EBs) invade host epithelial cells and differentiate into noninfectious, metabolically active reticulate bodies (RBs). EBs posses a unique outer envelope where rigidity is achieved by disulfide bonding among cysteine-rich envelope-associated proteins. Conversely, these disulfide bonds become reduced in RBs to accommodate vegetative growth, thereby linking the redox status of cysteine-rich envelope proteins with progression of the developmental cycle. We investigated the potential role of disulfide bonding within the chlamydial type III secretion system (T3SS), since activity of this system is also closely linked to development. We focused on structural components of the T3S apparatus that contain an unusually high number of cysteine residues compared to orthologs in other secretion systems. Nonreducing SDS-PAGE revealed that EB-localized apparatus proteins such as CdsF, CdsD, and CdsC form higher-order complexes mediated by disulfide bonding. The most dramatic alterations were detected for the needle protein CdsF. Significantly, disulfide bonding patterns shifted during differentiation of developmental forms and were completely reduced in RBs. Furthermore, at later time points during infection following RB to EB conversion, we found that CdsF is reoxidized into higher-order complexes. Overall, we conclude that the redox status of specific T3SS apparatus proteins is intimately linked to the developmental cycle and constitutes a newly appreciated aspect of functionally significant alterations within proteins of the chlamydial envelope.
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Kebbi-Beghdadi C, Batista C, Greub G. Permissivity of fish cell lines to three Chlamydia-related bacteria: Waddlia chondrophila, Estrella lausannensis and Parachlamydia acanthamoebae. ACTA ACUST UNITED AC 2011; 63:339-45. [PMID: 22092560 DOI: 10.1111/j.1574-695x.2011.00856.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 08/03/2011] [Accepted: 08/04/2011] [Indexed: 11/27/2022]
Abstract
Epitheliocystis is an infectious disease affecting gills and skin of various freshwater and marine fishes, associated with high mortality and reduced growth of survivors. Candidatus Piscichlamydia salmonis and Clavochlamydia salmonicola have recently been identified as aetiological agents of epitheliocystis in Atlantic Salmon. In addition, several other members of the Chlamydiales order have been identified in other fish species. To clarify the pathogenicity of Chlamydia-like organisms towards fishes, we investigated the permissivity of two fish cell lines, EPC-175 (Fathead Minnow) and RTG-2 (rainbow trout) to three Chlamydia-related bacteria: Waddlia chondrophila, Parachlamydia acanthamoebae and Estrella lausannensis. Quantitative PCR and immunofluorescence demonstrated that W. chondrophila and, to a lesser extent, E. lausannensis were able to replicate in the two cell lines tested. Waddlia chondrophila multiplied rapidly in its host cell and a strong cytopathic effect was observed. During E. lausannensis infection, we observed a limited replication of the bacteria not followed by host cell lysis. Very limited replication of P. acanthamoebae was observed in both cell lines tested. Given its high infectivity and cytopathic effect towards fish cell lines, W. chondrophila represents the most interesting Chlamydia-related bacteria to be used to develop an in vivo model of epitheliocystis disease in fishes.
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Affiliation(s)
- Carole Kebbi-Beghdadi
- Center for Research on Intracellular Bacteria (CRIB), Institute of Microbiology, University Hospital Center and University of Lausanne, Switzerland
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