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Cifuente JO, Colleoni C, Kalscheuer R, Guerin ME. Architecture, Function, Regulation, and Evolution of α-Glucans Metabolic Enzymes in Prokaryotes. Chem Rev 2024; 124:4863-4934. [PMID: 38606812 PMCID: PMC11046441 DOI: 10.1021/acs.chemrev.3c00811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2024]
Abstract
Bacteria have acquired sophisticated mechanisms for assembling and disassembling polysaccharides of different chemistry. α-d-Glucose homopolysaccharides, so-called α-glucans, are the most widespread polymers in nature being key components of microorganisms. Glycogen functions as an intracellular energy storage while some bacteria also produce extracellular assorted α-glucans. The classical bacterial glycogen metabolic pathway comprises the action of ADP-glucose pyrophosphorylase and glycogen synthase, whereas extracellular α-glucans are mostly related to peripheral enzymes dependent on sucrose. An alternative pathway of glycogen biosynthesis, operating via a maltose 1-phosphate polymerizing enzyme, displays an essential wiring with the trehalose metabolism to interconvert disaccharides into polysaccharides. Furthermore, some bacteria show a connection of intracellular glycogen metabolism with the genesis of extracellular capsular α-glucans, revealing a relationship between the storage and structural function of these compounds. Altogether, the current picture shows that bacteria have evolved an intricate α-glucan metabolism that ultimately relies on the evolution of a specific enzymatic machinery. The structural landscape of these enzymes exposes a limited number of core catalytic folds handling many different chemical reactions. In this Review, we present a rationale to explain how the chemical diversity of α-glucans emerged from these systems, highlighting the underlying structural evolution of the enzymes driving α-glucan bacterial metabolism.
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Affiliation(s)
- Javier O. Cifuente
- Instituto
Biofisika (UPV/EHU, CSIC), University of
the Basque Country, E-48940 Leioa, Spain
| | - Christophe Colleoni
- University
of Lille, CNRS, UMR8576-UGSF -Unité de Glycobiologie Structurale
et Fonctionnelle, F-59000 Lille, France
| | - Rainer Kalscheuer
- Institute
of Pharmaceutical Biology and Biotechnology, Heinrich Heine University, 40225 Dusseldorf, Germany
| | - Marcelo E. Guerin
- Structural
Glycobiology Laboratory, Department of Structural and Molecular Biology, Molecular Biology Institute of Barcelona (IBMB), Spanish
National Research Council (CSIC), Barcelona Science Park, c/Baldiri Reixac 4-8, Tower R, 08028 Barcelona, Catalonia, Spain
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2
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Triboulet S, N’Gadjaga MD, Niragire B, Köstlbacher S, Horn M, Aimanianda V, Subtil A. CT295 Is Chlamydia trachomatis’ Phosphoglucomutase and a Type 3 Secretion Substrate. Front Cell Infect Microbiol 2022; 12:866729. [PMID: 35795184 PMCID: PMC9251005 DOI: 10.3389/fcimb.2022.866729] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/24/2022] [Indexed: 11/13/2022] Open
Abstract
The obligate intracellular bacteria Chlamydia trachomatis store glycogen in the lumen of the vacuoles in which they grow. Glycogen catabolism generates glucose-1-phosphate (Glc1P), while the bacteria can take up only glucose-6-phosphate (Glc6P). We tested whether the conversion of Glc1P into Glc6P could be catalyzed by a phosphoglucomutase (PGM) of host or bacterial origin. We found no evidence for the presence of the host PGM in the vacuole. Two C. trachomatis proteins, CT295 and CT815, are potential PGMs. By reconstituting the reaction using purified proteins, and by complementing PGM deficient fibroblasts, we demonstrated that only CT295 displayed robust PGM activity. Intriguingly, we showed that glycogen accumulation in the lumen of the vacuole of a subset of Chlamydia species (C. trachomatis, C. muridarum, C. suis) correlated with the presence, in CT295 orthologs, of a secretion signal recognized by the type three secretion (T3S) machinery of Shigella. C. caviae and C. pneumoniae do not accumulate glycogen, and their CT295 orthologs lack T3S signals. In conclusion, we established that the conversion of Glc1P into Glc6P was accomplished by a bacterial PGM, through the acquisition of a T3S signal in a “housekeeping” protein. Acquisition of this signal likely contributed to shaping glycogen metabolism within Chlamydiaceae.
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Affiliation(s)
- Sébastien Triboulet
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Unité de Biologie Cellulaire de l’Infection Microbienne, Paris, France
| | - Maimouna D. N’Gadjaga
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Unité de Biologie Cellulaire de l’Infection Microbienne, Paris, France
- Sorbonne Université, Collège Doctoral, Paris, France
| | - Béatrice Niragire
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Unité de Biologie Cellulaire de l’Infection Microbienne, Paris, France
| | - Stephan Köstlbacher
- Centre for Microbiology and Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Matthias Horn
- Centre for Microbiology and Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Vishukumar Aimanianda
- Institut Pasteur, Université Paris Cité, CNRS UMR2000, Unité de Mycologie Moléculaire, Paris, France
| | - Agathe Subtil
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Unité de Biologie Cellulaire de l’Infection Microbienne, Paris, France
- *Correspondence: Agathe Subtil,
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3
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Colpaert M, Kadouche D, Ducatez M, Pillonel T, Kebbi-Beghdadi C, Cenci U, Huang B, Chabi M, Maes E, Coddeville B, Couderc L, Touzet H, Bray F, Tirtiaux C, Ball S, Greub G, Colleoni C. Conservation of the glycogen metabolism pathway underlines a pivotal function of storage polysaccharides in Chlamydiae. Commun Biol 2021; 4:296. [PMID: 33674787 PMCID: PMC7935935 DOI: 10.1038/s42003-021-01794-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 02/03/2021] [Indexed: 01/31/2023] Open
Abstract
The order Chlamydiales includes obligate intracellular pathogens capable of infecting mammals, fishes and amoeba. Unlike other intracellular bacteria for which intracellular adaptation led to the loss of glycogen metabolism pathway, all chlamydial families maintained the nucleotide-sugar dependent glycogen metabolism pathway i.e. the GlgC-pathway with the notable exception of both Criblamydiaceae and Waddliaceae families. Through detailed genome analysis and biochemical investigations, we have shown that genome rearrangement events have resulted in a defective GlgC-pathway and more importantly we have evidenced a distinct trehalose-dependent GlgE-pathway in both Criblamydiaceae and Waddliaceae families. Altogether, this study strongly indicates that the glycogen metabolism is retained in all Chlamydiales without exception, highlighting the pivotal function of storage polysaccharides, which has been underestimated to date. We propose that glycogen degradation is a mandatory process for fueling essential metabolic pathways that ensure the survival and virulence of extracellular forms i.e. elementary bodies of Chlamydiales.
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Affiliation(s)
- Matthieu Colpaert
- University of Lille, CNRS, UMR8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Derifa Kadouche
- University of Lille, CNRS, UMR8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Mathieu Ducatez
- University of Lille, CNRS, UMR8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Trestan Pillonel
- Institute of Microbiology, University of Lausanne and University Hospital Center, Lausanne, Switzerland
| | - Carole Kebbi-Beghdadi
- Institute of Microbiology, University of Lausanne and University Hospital Center, Lausanne, Switzerland
| | - Ugo Cenci
- University of Lille, CNRS, UMR8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Binquan Huang
- University of Lille, CNRS, UMR8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan/School of Agriculture, Yunnan University, Kunming, China
| | - Malika Chabi
- University of Lille, CNRS, UMR8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Emmanuel Maes
- University of Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, US 41 - UMS 2014 - PLBS, Lille, France
| | - Bernadette Coddeville
- University of Lille, CNRS, UMR8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Loïc Couderc
- University of Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, US 41 - UMS 2014 - PLBS, Lille, France
| | - Hélène Touzet
- University of Lille, CNRS, Centrale Lille, UMR 9189 - CRIStAL - Centre de Recherche en Informatique Signal et Automatique de Lille, Lille, France
| | - Fabrice Bray
- University of Lille, CNRS, USR 3290-MSAP-Miniaturisation pour la Synthèse, l'Analyse et la Protéomique, Lille, France
| | - Catherine Tirtiaux
- University of Lille, CNRS, UMR8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Steven Ball
- University of Lille, CNRS, UMR8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Gilbert Greub
- Institute of Microbiology, University of Lausanne and University Hospital Center, Lausanne, Switzerland
| | - Christophe Colleoni
- University of Lille, CNRS, UMR8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France.
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4
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Chlamydia Uses K + Electrical Signalling to Orchestrate Host Sensing, Inter-Bacterial Communication and Differentiation. Microorganisms 2021; 9:microorganisms9010173. [PMID: 33467438 PMCID: PMC7830353 DOI: 10.3390/microorganisms9010173] [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: 12/16/2020] [Revised: 01/08/2021] [Accepted: 01/08/2021] [Indexed: 12/30/2022] Open
Abstract
Prokaryotic communities coordinate quorum behaviour in response to external stimuli to control fundamental processes including inter-bacterial communication. The obligate intracellular bacterial pathogen Chlamydia adopts two developmental forms, invasive elementary bodies (EBs) and replicative reticulate bodies (RBs), which reside within a specialised membrane-bound compartment within the host cell termed an inclusion. The mechanisms by which this bacterial community orchestrates different stages of development from within the inclusion in coordination with the host remain elusive. Both prokaryotic and eukaryotic kingdoms exploit ion-based electrical signalling for fast intercellular communication. Here we demonstrate that RBs specifically accumulate potassium (K+) ions, generating a gradient. Disruption of this gradient using ionophores or an ion-channel inhibitor stalls the Chlamydia lifecycle, inducing persistence. Using photobleaching approaches, we establish that the RB is the master regulator of this [K+] differential and observe a fast K+ exchange between RBs revealing a role for this ion in inter-bacterial communication. Finally, we demonstrate spatio-temporal regulation of bacterial membrane potential during RB to EB differentiation within the inclusion. Together, our data reveal that Chlamydia harnesses K+ to orchestrate host sensing, inter-bacteria communication and pathogen differentiation.
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5
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Zhong G. Chlamydial Plasmid-Dependent Pathogenicity. Trends Microbiol 2016; 25:141-152. [PMID: 27712952 DOI: 10.1016/j.tim.2016.09.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 09/11/2016] [Accepted: 09/19/2016] [Indexed: 10/20/2022]
Abstract
Most Chlamydia species carry a 7.5kb plasmid encoding eight open reading frames conventionally called plasmid glycoproteins 1-8 or pGP1-8. Although the plasmid is not critical for chlamydial growth in vitro, its role in chlamydial pathogenesis is clearly demonstrated in the genital tracts of mice infected with Chlamydia muridarum, a model for investigating the human pathogen Chlamydia trachomatis. Plasmid-free C. trachomatis is also attenuated in both the mouse genital tract and nonhuman primate ocular tissue. Deficiency in pGP3 alone, which is regulated by pGP4, largely reproduced the in vivo but not in vitro phenotypes of the plasmid-free organisms, suggesting that pGP3 is a key in vivo virulence factor. The positive and negative regulations of some chromosomal genes by pGP4 and pGP5, respectively, may allow the plasmid to promote chlamydial adaptation to varied animal tissue environments. The focus of this review is to summarize the progress on the pathogenic functions of the plasmid-encoded open reading frames, which may motivate further investigation of the molecular mechanisms of chlamydial pathogenicity and development of medical utility of the chlamydial plasmid system.
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Affiliation(s)
- Guangming Zhong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.
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6
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Gehre L, Gorgette O, Perrinet S, Prevost MC, Ducatez M, Giebel AM, Nelson DE, Ball SG, Subtil A. Sequestration of host metabolism by an intracellular pathogen. eLife 2016; 5:e12552. [PMID: 26981769 PMCID: PMC4829429 DOI: 10.7554/elife.12552] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 03/15/2016] [Indexed: 01/22/2023] Open
Abstract
For intracellular pathogens, residence in a vacuole provides a shelter against cytosolic host defense to the cost of limited access to nutrients. The human pathogen Chlamydia trachomatis grows in a glycogen-rich vacuole. How this large polymer accumulates there is unknown. We reveal that host glycogen stores shift to the vacuole through two pathways: bulk uptake from the cytoplasmic pool, and de novo synthesis. We provide evidence that bacterial glycogen metabolism enzymes are secreted into the vacuole lumen through type 3 secretion. Our data bring strong support to the following scenario: bacteria co-opt the host transporter SLC35D2 to import UDP-glucose into the vacuole, where it serves as substrate for de novo glycogen synthesis, through a remarkable adaptation of the bacterial glycogen synthase. Based on these findings we propose that parasitophorous vacuoles not only offer protection but also provide a microorganism-controlled metabolically active compartment essential for redirecting host resources to the pathogens.
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Affiliation(s)
- Lena Gehre
- Unité de Biologie cellulaire de l'infection microbienne, Institut Pasteur, Paris, France.,CNRS UMR3691, Paris, France
| | - Olivier Gorgette
- Plate-forme de Microscopie Ultrastructurale, Imagopole, Institut Pasteur, Paris, France
| | - Stéphanie Perrinet
- Unité de Biologie cellulaire de l'infection microbienne, Institut Pasteur, Paris, France.,CNRS UMR3691, Paris, France
| | | | - Mathieu Ducatez
- Unité de Glycobiologie Structurale et Fonctionnelle - CNRS UMR8576, Université de Lille, Lille, France
| | - Amanda M Giebel
- Department of Biology, Indiana University Bloomington, Bloomington, United States
| | - David E Nelson
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, United States
| | - Steven G Ball
- Unité de Glycobiologie Structurale et Fonctionnelle - CNRS UMR8576, Université de Lille, Lille, France
| | - Agathe Subtil
- Unité de Biologie cellulaire de l'infection microbienne, Institut Pasteur, Paris, France.,CNRS UMR3691, Paris, France
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7
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The Proteome of the Isolated Chlamydia trachomatis Containing Vacuole Reveals a Complex Trafficking Platform Enriched for Retromer Components. PLoS Pathog 2015; 11:e1004883. [PMID: 26042774 PMCID: PMC4456400 DOI: 10.1371/journal.ppat.1004883] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 04/14/2015] [Indexed: 12/22/2022] Open
Abstract
Chlamydia trachomatis is an important human pathogen that replicates inside the infected host cell in a unique vacuole, the inclusion. The formation of this intracellular bacterial niche is essential for productive Chlamydia infections. Despite its importance for Chlamydia biology, a holistic view on the protein composition of the inclusion, including its membrane, is currently missing. Here we describe the host cell-derived proteome of isolated C. trachomatis inclusions by quantitative proteomics. Computational analysis indicated that the inclusion is a complex intracellular trafficking platform that interacts with host cells’ antero- and retrograde trafficking pathways. Furthermore, the inclusion is highly enriched for sorting nexins of the SNX-BAR retromer, a complex essential for retrograde trafficking. Functional studies showed that in particular, SNX5 controls the C. trachomatis infection and that retrograde trafficking is essential for infectious progeny formation. In summary, these findings suggest that C. trachomatis hijacks retrograde pathways for effective infection. The important human pathogen Chlamydia trachomatis causes 100 million new infections each year world-wide. It replicates inside the infected host cell in a unique vacuole, the inclusion. Currently, the nature, and specifically the protein composition of the inclusion, is poorly defined. Here, we described the host cell-derived inclusion proteome by quantitative proteomics using a newly established method to purify inclusions from infected epithelial cells. We showed that the inclusion is a complex intracellular trafficking platform that is well embedded into the organellar network and interacts with host cells’ antero- and retrograde trafficking pathways. Particularly, SNX1, 2, 5 and 6, components of the retromer, are recruited to the inclusion and seem to control the infection. We found also that retrograde trafficking is essential for Chlamydia progeny formation. Our study provides new insights into how the obligate intracellular bacterium C. trachomatis interacts with the eukaryotic host cell and subverts host cell functions for productive infection.
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8
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Destruction of tissue, cells and organelles in type 1 diabetic rats presented at macromolecular resolution. Sci Rep 2014; 3:1804. [PMID: 23652855 PMCID: PMC3647201 DOI: 10.1038/srep01804] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 04/19/2013] [Indexed: 01/15/2023] Open
Abstract
Finding alternatives for insulin therapy and making advances in etiology of type 1 diabetes benefits from a full structural and functional insight into Islets of Langerhans. Electron microscopy (EM) can visualize Islet morphology at the highest possible resolution, however, conventional EM only provides biased snapshots and lacks context. We developed and employed large scale EM and compiled a resource of complete cross sections of rat Islets during immuno-destruction to provide unbiased structural insight of thousands of cells at macromolecular resolution. The resource includes six datasets, totalling 25.000 micrographs, annotated for cellular and ultrastructural changes during autoimmune diabetes. Granulocytes are attracted to the endocrine tissue, followed by extravasation of a pleiotrophy of leukocytes. Subcellullar changes in beta cells include endoplasmic reticulum stress, insulin degranulation and glycogen accumulation. Rare findings include erythrocyte extravasation and nuclear actin-like fibers. While we focus on a rat model of autoimmune diabetes, our approach is general applicable.
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9
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Lu C, Lei L, Peng B, Tang L, Ding H, Gong S, Li Z, Wu Y, Zhong G. Chlamydia trachomatis GlgA is secreted into host cell cytoplasm. PLoS One 2013; 8:e68764. [PMID: 23894341 PMCID: PMC3722199 DOI: 10.1371/journal.pone.0068764] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 06/04/2013] [Indexed: 12/03/2022] Open
Abstract
Glycogen has been localized both inside and outside Chlamydia trachomatis organisms. We now report that C. trachomatis glycogen synthase (GlgA) was detected in both chlamydial organism-associated and -free forms. The organism-free GlgA molecules were localized both in the lumen of chlamydial inclusions and in the cytosol of host cells. The cytosolic GlgA displayed a distribution pattern similar to that of a known C. trachomatis-secreted protease, CPAF. The detection of GlgA was specific since the anti-GlgA antibody labeling was only removed by preabsorption with GlgA but not CPAF fusion proteins. GlgA was detectable at 12h and its localization into host cell cytosol only became apparent at 24h after infection. The cytosolic localization of GlgA was conserved among all C. trachomatis serovars. However, the significance of the GlgA secretion into host cell cytoplasm remains unclear since, while expression of chlamydial GlgA in HeLa cells increased glycogen stores, it did not affect a subsequent infection with C. trachomatis. Similar to several other C. trachomatis-secreted proteins, GlgA is immunogenic in women urogenitally infected with C. trachomatis, suggesting that GlgA is expressed and may be secreted into host cell cytosol during C. trachomatis infection in humans. These findings have provided important information for further understanding C. trachomatis pathogenic mechanisms.
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Affiliation(s)
- Chunxue Lu
- Department of Pathogen Biology, University of South China, Hengyang, Hunan, China
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Lei Lei
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Bo Peng
- Department of Pathogen Biology, University of South China, Hengyang, Hunan, China
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Lingli Tang
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Honglei Ding
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Siqi Gong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Zhongyu Li
- Department of Pathogen Biology, University of South China, Hengyang, Hunan, China
| | - Yimou Wu
- Department of Pathogen Biology, University of South China, Hengyang, Hunan, China
- * E-mail: (YW); (GZ)
| | - Guangming Zhong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- * E-mail: (YW); (GZ)
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10
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Virulence determinants in the obligate intracellular pathogen Chlamydia trachomatis revealed by forward genetic approaches. Proc Natl Acad Sci U S A 2012; 109:1263-8. [PMID: 22232666 DOI: 10.1073/pnas.1117884109] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Chlamydia trachomatis, a pathogen responsible for diseases of significant clinical and public health importance, remains poorly characterized because of its intractability to routine molecular genetic manipulation. We have developed a combinatorial approach to rapidly generate a comprehensive library of genetically defined mutants. Chemical mutagenesis, coupled with whole-genome sequencing (WGS) and a system for DNA exchange within infected cells, was used to generate Chlamydia mutants with distinct phenotypes, map the underlying genetic lesions, and generate isogenic strains. As a result, we identified mutants with altered glycogen metabolism, including an attenuated strain defective for type II secretion. The coupling of chemically induced gene variation and WGS to establish genotype-phenotype associations should be broadly applicable to the large list of medically and environmentally important microorganisms currently intractable to genetic analysis.
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11
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The Chlamydia trachomatis plasmid is a transcriptional regulator of chromosomal genes and a virulence factor. Infect Immun 2008; 76:2273-83. [PMID: 18347045 DOI: 10.1128/iai.00102-08] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chlamydia trachomatis possesses a cryptic 7.5-kb plasmid of unknown function. Here, we describe a comprehensive molecular and biological characterization of the naturally occurring plasmidless human C. trachomatis strain L2(25667R). We found that despite minimal chromosomal polymorphisms, the LGV strain L2(25667R) was indistinguishable from plasmid-positive strain L2(434) with regard to its in vitro infectivity characteristics such as growth kinetics, plaquing efficiency, and plaque size. The only in vitro phenotypic differences between L2(434) and L2(25667R) were the accumulation of glycogen granules in the inclusion matrix and the lack of the typical intrainclusion Brownian-like movement characteristic of C. trachomatis strains. Conversely, we observed a marked difference between the two strains in their abilities to colonize and infect the female mouse genital tract. The 50% infective dose of plasmidless strain L2(25667R) was 400-fold greater (4 x 10(6) inclusion-forming units [IFU]) than that of plasmid-bearing strain L2(434) (1 x 10(4) IFU). Transcriptome analysis of the two strains demonstrated a decrease in the transcript levels of a subset of chromosomal genes for strain L2(25667R). Among those genes was glgA, encoding glycogen synthase, a finding consistent with the failure of L2(25667R) to accumulate glycogen granules. These findings support a primary role for the plasmid in in vivo infectivity and suggest that virulence is controlled, at least in part, by the plasmid's ability to regulate the expression of chromosomal genes. Our findings have important implications in understanding a role for the plasmid in the pathogenesis of human infection and disease.
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12
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Abstract
Chlamydiae are widespread bacterial pathogens responsible for a broad range of diseases, including sexually transmitted infections, pneumonia and trachoma. To validate the existence of hitherto hypothetical proteins predicted from recent chlamydial genome sequencing projects and to examine the patterns of expression of key components at the protein level, we have surveyed the expressed proteome of Chlamydia trachomatis strain L2. A combination of two-dimensional gel analysis, multi-dimensional protein identification (MudPIT) and nanocapillary liquid chromatography-tandem mass spectrometry allowed a total of 328 chlamydial proteins to be unambiguously assigned. Proteins identified as being expressed in the metabolically inert form, elementary body, of Chlamydia include the entire set of predicted glycolytic enzymes, indicating that metabolite flux rather than de novo synthesis of this pathway is triggered upon infection of host cells. An enzyme central to cell wall biosynthesis was also detected in the intracellular form, reticulate body, of Chlamydia, suggesting that the peptidoglycan is produced during growth within host cells. Other sets of proteins identified include 17 outer membrane-associated proteins of potential significance in vaccine studies and 67 proteins previously annotated as hypothetical or conserved hypothetical. Taken together, >/=35% of the predicted proteome for C. trachomatis has been experimentally verified, representing the most extensive survey of any chlamydial proteome to date.
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Affiliation(s)
- Paul Skipp
- Centre for Proteomic Research, and School of Biological Sciences, University of Southampton, Southampton, UK.
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13
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Nicholson TL, Olinger L, Chong K, Schoolnik G, Stephens RS. Global stage-specific gene regulation during the developmental cycle of Chlamydia trachomatis. J Bacteriol 2003; 185:3179-89. [PMID: 12730178 PMCID: PMC154084 DOI: 10.1128/jb.185.10.3179-3189.2003] [Citation(s) in RCA: 165] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Distinct morphological changes associated with the complex development cycle of the obligate intracellular bacterial pathogen Chlamydia trachomatis have been historically well characterized by microscopy. A number of temporally regulated genes have been characterized previously, suggesting that the chlamydial developmental cycle is regulated at the transcriptional level. This hypothesis was tested by microarray analysis in which the entire C. trachomatis genome was analyzed, providing a comprehensive assessment of global gene regulation throughout the chlamydial developmental cycle. Seven temporally cohesive gene clusters were identified, with 22% (189 genes) of the genome differentially expressed during the developmental cycle. The correlation of these gene clusters with hallmark morphological events of the chlamydial developmental cycle suggests three global stage-specific networks of gene regulation.
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Affiliation(s)
- Tracy L Nicholson
- Division of Infectious Diseases, School of Public Health, University of California, Berkeley, California 94720, USA
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14
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Abstract
The biological significance of glycogen accumulation and how the process is regulated in Chlamydia trachomatis remains poorly defined. C. trachomatis-infected HeLa cells were cultured in medium containing various glucose concentrations (0, 0.1, 1 or 10 mg ml-1) or in the presence of gluconeogenic carbon sources (20 mM glutamate, 20 mM malate, 20 mM alpha-ketoglutarate or 20 mM oxaloacetate), and the effects of these different culture conditions on the production of infectious chlamydial elementary bodies and glycogen accumulation were monitored. When chlamydiae were cultured in glucose concentrations greater than 1 mg ml-1, optimal growth and maximal glycogen accumulation occurred. In contrast to uninfected HeLa cells, which increased their glycogen stores when grown in the presence of high glucose concentrations, chlamydial glycogen accumulation remained essentially constant. When cultured in medium supplemented with either reduced glucose concentrations or any of the gluconeogenic carbon sources, chlamydiae still grew; however, the yield of elementary bodies was substantially decreased, and there was no significant amount of glycogen accumulated by host HeLa cells or C. trachomatis. This suggests that glycogen accumulation may not be essential for chlamydial survival. Reverse transcriptase-polymerase chain reaction (RT-PCR) results indicated that, despite the fact that the source and amount of carbon available in the medium affected chlamydial glycogen accumulation, the expression of genes required for glycogen metabolism was not significantly changed. Similarly, the expression of several genes encoding key enzymes of central metabolism was not affected by alterations in carbon source or availability. Taken together, the data suggest that, unlike most free-living bacteria, chlamydia are unable to alter the expression of genes involved in carbon metabolism in response to changes in environmental conditions.
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Affiliation(s)
- E R Iliffe-Lee
- Department of Medical Microbiology, University of Manitoba, 730 William Avenue, Winnipeg, Manitoba, Canada
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15
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Miyashita N, Matsumoto A, Matsushima T. In vitro susceptibility of 7.5-kb common plasmid-free Chlamydia trachomatis strains. Microbiol Immunol 2000; 44:267-9. [PMID: 10832970 DOI: 10.1111/j.1348-0421.2000.tb02493.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using a new plaque cloning technique, we obtained unique Chlamydia trachomatis strains which were confirmed to be free of the 7.5-kb common plasmid and glycogen in inclusions. The in vitro susceptibility of these strains to various chemotherapeutic agents was tested by comparison with their parent strains and clinical isolates possessing the common plasmid. No difference was detected for any of the agents tested, indicating that the 7.5-kb common plasmid is unrelated to the drug resistance of C. trachomatis.
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Affiliation(s)
- N Miyashita
- Department of Medicine, Kawasaki Medical School, Kurashiki, Okayama, Japan.
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16
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Shaw EI, Dooley CA, Fischer ER, Scidmore MA, Fields KA, Hackstadt T. Three temporal classes of gene expression during the Chlamydia trachomatis developmental cycle. Mol Microbiol 2000; 37:913-25. [PMID: 10972811 DOI: 10.1046/j.1365-2958.2000.02057.x] [Citation(s) in RCA: 191] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The obligate intracellular bacterium Chlamydia trachomatis has a unique developmental cycle that involves functionally and morphologically distinct cell types adapted for extracellular survival and intracellular multiplication. Infection is initiated by an environmentally resistant cell type called an elementary body (EB). Over the first several hours of infection, EBs differentiate into a larger replicative form, termed the reticulate body (RB). Late in the infectious process, RBs asynchronously begin to differentiate back to EBs, which accumulate within the lumen of the inclusion until released from the host cell for subsequent rounds of infection. In an effort to characterize temporal gene expression in relation to the chlamydial developmental cycle, we have used quantitative-competitive polymerase chain reaction (QC-PCR) and reverse transcription (RT)-PCR techniques. These analyses demonstrate that C. trachomatis double their DNA content every 2-3 h, with synthesis beginning between 2 and 4 h after infection. We determined the onset of transcription of specific temporal classes of developmentally expressed genes. RT-PCR analysis was performed on several genes encoding key enzymes or components of essential biochemical pathways and functions. This comparison encompassed approximately 8% of open reading frames on the C. trachomatis genome. In analysis of total RNA samples harvested at 2, 6, 12 and 20 h after infection, using conditions under which a single chlamydial transcript per infected cell is detected, three major temporal classes of gene expression were resolved. Initiation of transcription appears to occur in three temporal classes which we have operationally defined as: early, which are detected by 2 h after infection during the germination of EBs to RBs; mid-cycle, which appear between 6 and 12 h after infection and represent transcripts expressed during the growth and multiplication of RBs; or late, which appear between 12 and 20 h after infection and represent those genes transcribed during the terminal differentiation of RBs to EBs. Collectively, the data suggest that chlamydial early gene functions are weighted toward initiation of macromolecular synthesis and the establishment of their intracellular niche by modification of the inclusion membrane. Surprisingly, representative enzymes of intermediary metabolism and structural proteins do not appear to be transcribed until 10-12 h after infection; coinciding with the onset of observed binary fission of RBs. Late gene functions appear to be predominately those associated with the terminal differentiation of RBs back to EBs.
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Affiliation(s)
- E I Shaw
- Host-Parasite Interactions Section, Laboratory of Intracellular Parasites, Hamilton, MT 59840, USA
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17
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Chun Y, Yin ZD. Glycogen assay for diagnosis of female genital Chlamydia trachomatis infection. J Clin Microbiol 1998; 36:1081-2. [PMID: 9542941 PMCID: PMC104693 DOI: 10.1128/jcm.36.4.1081-1082.1998] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Chlamydia trachomatis can synthesize glycogen at various stages in its developmental cycle. The glycogen content of female genital epithelial cells was detected by anthrone, and the results were compared with those from PCR. A total of 320 cervical samples were examined. Of 92 specimens that were positive by PCR, 78 were positive and 14 were negative by the glycogen assay. Of 228 specimens that were negative by PCR, 220 were negative and 8 were positive by the glycogen assay. The sensitivity and specificity of the glycogen assay obtained from these data were 84.8% (78 of 92) and 96.5% (220 of 228), respectively. Use of the glycogen assay to detect the glycogen content in genital epithelial cells may be helpful in the diagnosis of C. trachomatis infection. This is an easy, fast, and inexpensive assay and can be done in less-sophisticated labs.
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Affiliation(s)
- Y Chun
- Department of Microbiology, Chongqing University of Medical Sciences, People's Republic of China.
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