1
|
Rockey DD, Wang X, Debrine A, Grieshaber N, Grieshaber SS. Metabolic dormancy in Chlamydia trachomatis treated with different antibiotics. Infect Immun 2024; 92:e0033923. [PMID: 38214508 PMCID: PMC10863404 DOI: 10.1128/iai.00339-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 12/11/2023] [Indexed: 01/13/2024] Open
Abstract
Diseases caused by Chlamydia spp. are often associated with persistent infections. Chlamydial persistence is commonly associated with a unique non-infectious intracellular developmental form, termed an aberrant form. Although infectious chlamydiae can be cultured consistently in cells stressed to aberrancy, their role in persistence is not clear. Recovery from antibiotic stress was explored as a model to determine how survival of non-aberrant chlamydiae, in the presence of fully inhibitory drug concentrations, may participate in persistence. Assays included incubation in quinolones, tetracyclines, or chloramphenicol for differing lengths of time, followed by an extended recovery period in antibiotic-free media. Culturable elementary bodies were not detected during treatment with each antibiotic, but viable and culturable Chlamydia trachomatis emerged after the drug was removed. Time-lapse imaging of live, antibiotic-treated infected cells identified metabolically dormant developmental forms within cells that emerged to form typical productive inclusions. The effects of the increasing concentration of most tested antibiotics led to predictable inhibitory activity, in which the survival rate decreased with increasing drug concentration. In contrast, in fluoroquinolone-treated cells, there was a paradoxical increase in productive development that was directly correlated with drug concentration and inversely associated with aberrant form production. This model system uncovers a unique chlamydial persistence pathway that does not involve the chlamydial aberrant form. The association between productive latency and metabolic dormancy is consistent with models for many bacterial species and may lead to a different interpretation of mechanisms of chlamydial persistence in patients.IMPORTANCEThe life history of most pathogens within the genus Chlamydia relies on lengthy persistence in the host. The most generally accepted model for Chlamydia spp. persistence involves an unusual developmental stage, termed the aberrant form, which arises during conditions that mimic a stressful host environment. In this work, we provide an alternate model for chlamydial persistence in the face of antibiotic stress. This model may be relevant to antibiotic treatment failures in patients infected with C. trachomatis.
Collapse
Affiliation(s)
- Daniel D. Rockey
- Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Xisheng Wang
- Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Abigail Debrine
- Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Nicole Grieshaber
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, USA
| | | |
Collapse
|
2
|
Herron CL, Ruse NE, Rockey DD, Sanders JL, Peterson JT, Schreck CB, Kent ML. Aeromonas salmonicida, causative agent of salmonid furunculosis, isolated from the freshwater parasitic copepod, Salmincola californiensis. J Fish Dis 2024; 47:e13885. [PMID: 37947250 DOI: 10.1111/jfd.13885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 10/23/2023] [Accepted: 10/27/2023] [Indexed: 11/12/2023]
Abstract
Here, we provide evidence that the freshwater parasitic copepod, Salmincola californiensis, acts as a vector for Aeromonas salmonicida. While investigating the effects of S. californiensis on Chinoook salmon (Oncorhynchus tshawytscha), we tangentially observed that fish infected with the copepod developed furunculosis, caused by A. salmonicida. This occurred despite being reared in pathogen-free well water in a research facility with no prior history of spontaneous infection. We further investigated the possibility of S. californiensis to serve as a vector for the bacterium via detection of fluorescently labelled A. salmonicida inside the egg sacs from copepods in which the fish hosts were experimentally infected with GFP-A449 A. salmonicida. We then evaluated copepod egg sacs that were collected from adult Chinook salmon from a freshwater hatchery with A. salmonicida infections confirmed by either culture or PCR. The bacterium was cultured on tryptic soy agar plates from 75% of the egg sacs, and 61% were positive by PCR. These three separate experiments indicate an alternative tactic of transmission in addition to direct transmission of A. salmonicida in captivity. The copepod may play an important role in transmission of the bacterium when fish are more dispersed, such as in the wild.
Collapse
Affiliation(s)
- Crystal L Herron
- Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Natassia E Ruse
- Carlson College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, USA
- Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon, USA
- VCA Rock Creek Animal Hospital, Aloha, Oregon, USA
| | - Daniel D Rockey
- Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Justin L Sanders
- Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon, USA
| | - James T Peterson
- Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Corvallis, Oregon, USA
- U.S. Geological Survey, Oregon Cooperative Fish and Wildlife Research Unit, Corvallis, Oregon, USA
| | - Carl B Schreck
- Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Michael L Kent
- Department of Microbiology, Oregon State University, Corvallis, Oregon, USA
| |
Collapse
|
3
|
Debrine AM, Karplus PA, Rockey DD. A structural foundation for studying chlamydial polymorphic membrane proteins. Microbiol Spectr 2023; 11:e0324223. [PMID: 37882824 PMCID: PMC10715098 DOI: 10.1128/spectrum.03242-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 09/18/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE Infections by bacteria in the genus Chlamydia cause a range of widespread and potentially debilitating conditions in humans and other animals. We analyzed predicted structures of a family of proteins that are potential vaccine targets found in all Chlamydia spp. Our findings deepen the understanding of protein structure, provide a descriptive framework for discussion of the protein structure, and outline regions of the proteins that may be key targets in host-microbe interactions and anti-chlamydial immunity.
Collapse
Affiliation(s)
- Abigail M. Debrine
- Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon, USA
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, USA
| | - P. Andrew Karplus
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, USA
| | - Daniel D. Rockey
- Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon, USA
| |
Collapse
|
4
|
DeBoer AG, Lei L, Yang C, Martens CA, Anzick SL, Antonioli-Schmit S, Suchland RJ, McClarty G, Caldwell HD, Rockey DD. TargeTron Inactivation of Chlamydia trachomatis gseA Results in a Lipopolysaccharide 3-Deoxy-d-Manno-Oct-2-Ulosonic Acid-Deficient Strain That Is Cytotoxic for Cells. Infect Immun 2023; 91:e0009623. [PMID: 37255490 PMCID: PMC10353364 DOI: 10.1128/iai.00096-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 03/17/2023] [Indexed: 06/01/2023] Open
Abstract
All members of the family Chlamydiaceae have lipopolysaccharides (LPS) that possess a shared carbohydrate trisaccharide antigen, 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) that is functionally uncharacterized. A single gene, genus-specific epitope (gseA), is responsible for attaching the tri-Kdo to lipid IVA. To investigate the function of Kdo in chlamydial host cell interactions, we made a gseA-null strain (L2ΔgseA) by using TargeTron mutagenesis. Immunofluorescence microscopy and immunoblotting with a Kdo-specific monoclonal antibody demonstrated that L2ΔgseA lacked Kdo. L2ΔgseA reacted by immunoblotting with a monoclonal antibody specific for a conserved LPS glucosamine-PO4 epitope, indicating that core lipid A was retained by the mutant. The mutant strain produced a similar number of inclusions as the parental strain but yielded lower numbers of infectious elementary bodies. Transmission electron microscopy of L2ΔgseA-infected cells showed atypical developmental forms and a reduction in the number of elementary bodies. Immunoblotting of dithiothreitol-treated L2ΔgseA-infected cells lysates revealed a marked reduction in outer membrane OmcB disulfide cross-linking, suggesting that the elementary body outer membrane structure was affected by the lack of Kdo. Notably, lactic acid dehydrogenase release by infected cells demonstrated that L2ΔgseA was significantly more cytotoxic to host cells than the wild type. The cytotoxic phenotype may result from an altered outer membrane biogenesis structure and/or function or, conversely, from a direct pathobiological effect of Kdo on an unknown host cell target. These findings implicate a previously unrecognized role for Kdo in host cell interactions that facilitates postinfection host cell survival.
Collapse
Affiliation(s)
- Addison G. DeBoer
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Lei Lei
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Chunfu Yang
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Craig A. Martens
- National Institute of Allergy and Infectious Disease, Rocky Mountain Laboratory, Hamilton, Montana, USA
| | - Sarah L. Anzick
- National Institute of Allergy and Infectious Disease, Rocky Mountain Laboratory, Hamilton, Montana, USA
| | - Sophia Antonioli-Schmit
- National Institute of Allergy and Infectious Disease, Rocky Mountain Laboratory, Hamilton, Montana, USA
| | - Robert J. Suchland
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington
| | - Grant McClarty
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba Winnipeg, Winnipeg, Manitoba, Canada
| | - Harlan D. Caldwell
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Daniel D. Rockey
- Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon, USA
| |
Collapse
|
5
|
Garvin LE, DeBoer AG, Carrell SJ, Wang X, Rockey DD. Microscopic Analysis of the Chlamydia abortus Inclusion and Its Interaction with Those Formed by Other Chlamydial Species. Infect Immun 2022; 90:e0049921. [PMID: 35099268 PMCID: PMC8929342 DOI: 10.1128/iai.00499-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 01/18/2022] [Indexed: 11/20/2022] Open
Abstract
The Chlamydiae are obligate intracellular pathogens that develop and multiply within a poorly characterized parasitophorous vacuole (the inclusion) during growth. Chlamydia abortus is a major pathogen of sheep and other ruminants, and its inclusion development is poorly characterized. We used immunofluorescence microscopy, quantitative culture, and qPCR to examine C. abortus inclusion development and to examine the interaction of C. abortus inclusions with those formed by other species. Antibodies used in these studies include sera from ewes from production facilities that were naturally infected with C. abortus. Multiple inclusions are often found in C. abortus-infected cells, even in populations infected at very low multiplicity of infection. Labeling of fixed cells with sera from infected sheep revealed fibrous structures that extend away from the inclusion into the cytoplasm of the host cell. C. abortus inclusions fused with C. caviae and C. psittaci inclusions in coinfected cells. Inclusions formed by C. abortus and C. caviae did not fuse with inclusions formed by C. trachomatis, C. pneumoniae, or C. pecorum. The ability of inclusions to fuse was correlated with the overall genomic relatedness between species, and with sequence similarity in the inclusion membrane protein IncA. Quantitative PCR data demonstrated that C. abortus grows at a decreased rate during coinfections with C. caviae, while C. caviae growth was unaffected. The collected data add depth to our understanding of inclusion development in this significant zoonotic veterinary pathogen.
Collapse
Affiliation(s)
- Lotisha E. Garvin
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, USA
| | - Addison G. DeBoer
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, USA
| | - Steven J. Carrell
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, USA
| | - Xisheng Wang
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, USA
| | - Daniel D. Rockey
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, USA
| |
Collapse
|
6
|
Marti H, Suchland RJ, Rockey DD. The Impact of Lateral Gene Transfer in Chlamydia. Front Cell Infect Microbiol 2022; 12:861899. [PMID: 35321311 PMCID: PMC8936141 DOI: 10.3389/fcimb.2022.861899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 02/07/2022] [Indexed: 11/24/2022] Open
Abstract
Lateral gene transfer (LGT) facilitates many processes in bacterial ecology and pathogenesis, especially regarding pathogen evolution and the spread of antibiotic resistance across species. The obligate intracellular chlamydiae, which cause a range of diseases in humans and animals, were historically thought to be highly deficient in this process. However, research over the past few decades has demonstrated that this was not the case. The first reports of homologous recombination in the Chlamydiaceae family were published in the early 1990s. Later, the advent of whole-genome sequencing uncovered clear evidence for LGT in the evolution of the Chlamydiaceae, although the acquisition of tetracycline resistance in Chlamydia (C.) suis is the only recent instance of interphylum LGT. In contrast, genome and in vitro studies have shown that intraspecies DNA exchange occurs frequently and can even cross species barriers between closely related chlamydiae, such as between C. trachomatis, C. muridarum, and C. suis. Additionally, whole-genome analysis led to the identification of various DNA repair and recombination systems in C. trachomatis, but the exact machinery of DNA uptake and homologous recombination in the chlamydiae has yet to be fully elucidated. Here, we reviewed the current state of knowledge concerning LGT in Chlamydia by focusing on the effect of homologous recombination on the chlamydial genome, the recombination machinery, and its potential as a genetic tool for Chlamydia.
Collapse
Affiliation(s)
- Hanna Marti
- Institute of Veterinary Pathology, Vetsuisse-Faculty, University of Zurich, Zurich, Switzerland
- *Correspondence: Hanna Marti,
| | - Robert J. Suchland
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, United States
| | - Daniel D. Rockey
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR, United States
| |
Collapse
|
7
|
Dimond ZE, Suchland RJ, Baid S, LaBrie SD, Soules KR, Stanley J, Carrell S, Kwong F, Wang Y, Rockey DD, Hybiske K, Hefty PS. Inter-species lateral gene transfer focused on the Chlamydia plasticity zone identifies loci associated with immediate cytotoxicity and inclusion stability. Mol Microbiol 2021; 116:1433-1448. [PMID: 34738268 PMCID: PMC9119408 DOI: 10.1111/mmi.14832] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 10/13/2021] [Indexed: 12/20/2022]
Abstract
Chlamydia muridarum actively grows in murine mucosae and is a representative model of human chlamydial genital tract disease. In contrast, C. trachomatis infections in mice are limited and rarely cause disease. The factors that contribute to these differences in host adaptation and specificity remain elusive. Overall genomic similarity leads to challenges in the understanding of these significant differences in tropism. A region of major genetic divergence termed the plasticity zone (PZ) has been hypothesized to contribute to the host specificity. To evaluate this hypothesis, lateral gene transfer was used to generate multiple hetero-genomic strains that are predominately C. trachomatis but have replaced regions of the PZ with those from C. muridarum. In vitro analysis of these chimeras revealed C. trachomatis-like growth as well as poor mouse infection capabilities. Growth-independent cytotoxicity phenotypes have been ascribed to three large putative cytotoxins (LCT) encoded in the C. muridarum PZ. However, analysis of PZ chimeras supported that gene products other than the LCTs are responsible for cytopathic and cytotoxic phenotypes. Growth analysis of associated chimeras also led to the discovery of an inclusion protein, CTL0402 (CT147), and homolog TC0424, which was critical for the integrity of the inclusion and preventing apoptosis.
Collapse
Affiliation(s)
- Zoe E. Dimond
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, USA
| | - Robert J. Suchland
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Srishti Baid
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, USA
| | - Scott D. LaBrie
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, USA
| | - Katelyn R. Soules
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, USA
| | - Jacob Stanley
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, USA
| | - Steven Carrell
- Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Forrest Kwong
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Yibing Wang
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Daniel D. Rockey
- Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Kevin Hybiske
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - P. Scott Hefty
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, USA
| |
Collapse
|
8
|
Suchland RJ, Dimond ZE, Putman TE, Rockey DD. Demonstration of Persistent Infections and Genome Stability by Whole-Genome Sequencing of Repeat-Positive, Same-Serovar Chlamydia trachomatis Collected From the Female Genital Tract. J Infect Dis 2017; 215:1657-1665. [PMID: 28368459 DOI: 10.1093/infdis/jix155] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 03/21/2017] [Indexed: 11/12/2022] Open
Abstract
Background The biology of recurrent or long-term infections of humans by Chlamydia trachomatis is poorly understood. Because repeated or persistent infections are correlated with serious complications in humans, understanding these processes may improve clinical management and public health disease control. Methods We conducted whole-genome sequence analysis on C. trachomatis isolates collected from a previously described patient set in which individuals were shown to be infected with a single serovar over a lengthy period. Results Data from 5 of 7 patients showed compelling evidence for the ability of these patients to harbor the same strain for 3-5 years. Mutations in these strains were cumulative, very uncommon, and not linked to any single protein or pathway. Serovar J strains isolated from 1 patient 3 years apart did not accumulate a single base change across the genome. In contrast, the sequence results of 2 patients, each infected only with serovar Ia strains, revealed multiple same-serovar infections over 1-5 years. Conclusions These data demonstrate examples of long-term persistence in patients in the face of repeated antibiotic therapy and show that pathogen mutational strategies are not important in persistence of this pathogen in patients.
Collapse
Affiliation(s)
- Robert J Suchland
- Department of Allergy and Infectious Diseases, University of Washington School of Medicine, Seattle
| | - Zoe E Dimond
- College of Veterinary Medicine and Molecular and Cellular Biology Program, Oregon State University, Corvallis
| | - Timothy E Putman
- College of Veterinary Medicine and Molecular and Cellular Biology Program, Oregon State University, Corvallis
| | - Daniel D Rockey
- College of Veterinary Medicine and Molecular and Cellular Biology Program, Oregon State University, Corvallis
| |
Collapse
|
9
|
Cram ED, Rockey DD, Dolan BP. Chlamydia spp. development is differentially altered by treatment with the LpxC inhibitor LPC-011. BMC Microbiol 2017; 17:98. [PMID: 28438125 PMCID: PMC5402638 DOI: 10.1186/s12866-017-0992-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 03/28/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chlamydia species are obligate intracellular bacteria that infect a broad range of mammalian hosts. Members of related genera are pathogens of a variety of vertebrate and invertebrate species. Despite the diversity of Chlamydia, all species contain an outer membrane lipooligosaccharide (LOS) that is comprised of a genus-conserved, and genus-defining, trisaccharide 3-deoxy-D-manno-oct-2-ulosonic acid Kdo region. Recent studies with lipopolysaccharide inhibitors demonstrate that LOS is important for the C. trachomatis developmental cycle during RB- > EB differentiation. Here, we explore the effects of one of these inhibitors, LPC-011, on the developmental cycle of five chlamydial species. RESULTS Sensitivity to the drug varied in some of the species and was conserved between others. We observed that inhibition of LOS biosynthesis in some chlamydial species induced formation of aberrant reticulate bodies, while in other species, no change was observed to the reticulate body. However, loss of LOS production prevented completion of the chlamydial reproductive cycle in all species tested. In previous studies we found that C. trachomatis and C. caviae infection enhances MHC class I antigen presentation of a model self-peptide. We find that treatment with LPC-011 prevents enhanced host-peptide presentation induced by infection with all chlamydial-species tested. CONCLUSIONS The data demonstrate that LOS synthesis is necessary for production of infectious progeny and inhibition of LOS synthesis induces aberrancy in certain chlamydial species, which has important implications for the use of LOS synthesis inhibitors as potential antibiotics.
Collapse
Affiliation(s)
- Erik D Cram
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 105 Magruder Hall, Corvallis, OR, 97331, USA.
| | - Daniel D Rockey
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 105 Magruder Hall, Corvallis, OR, 97331, USA
| | - Brian P Dolan
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 105 Magruder Hall, Corvallis, OR, 97331, USA
| |
Collapse
|
10
|
Abstract
PCR-based approach was used to examine the rate of Chlamydia positivity in raptors from wild bird rehabilitation centers in Oregon. Three of 82 birds were identified as positive for Chlamydia with this PCR. Sequence analysis of 16S ribosomal DNA from 2 of these birds confirmed the presence of DNA from phylum Chlamydiae. One bird was positive for Chlamydia psittaci in both choanal and cloacal swabs. The second bird, a louse-infested red-tailed hawk, had evidence of choanal colonization by "Candidatus Rhabdochlamydia" spp. Our study describes evidence of this Chlamydia-like organism in the United States. This survey also suggests that the carriage rate of C. psittaci is low in raptors in Oregon wild bird rehabilitation centers, and that care must be taken in the design of PCR primers for phylum Chlamydiae such that colonization by insect endosymbionts is not mistaken for an infection by known chlamydial pathogens.
Collapse
Affiliation(s)
- Sophie J Jouffroy
- College of Veterinary Medicine, Oregon State University, Corvallis, OR
| | | | - Robert J Bildfell
- College of Veterinary Medicine, Oregon State University, Corvallis, OR
| | - Daniel D Rockey
- College of Veterinary Medicine, Oregon State University, Corvallis, OR
| |
Collapse
|
11
|
Putman TE, Suchland RJ, Ivanovitch JD, Rockey DD. Culture-independent sequence analysis of Chlamydia trachomatis in urogenital specimens identifies regions of recombination and in-patient sequence mutations. Microbiology (Reading) 2013; 159:2109-2117. [PMID: 23842467 DOI: 10.1099/mic.0.070029-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A culture-independent genome sequencing approach was developed and used to examine genomic variability in Chlamydia trachomatis-positive specimens that were collected from patients in the Seattle, WA, USA, area. The procedure is based on an immunomagnetic separation approach with chlamydial LPS-specific mAbs, followed by DNA purification and total DNA amplification, and subsequent Illumina-based sequence analysis. Quality of genome sequencing was independent of the total number of inclusion-forming units determined for the sample and the amount of non-chlamydial DNA in the Illumina libraries. A geographically and temporally linked clade of isolates was identified with evidence of several different regions of recombination and variable ompA sequence types, suggesting that recombination is common within outbreaks. Culture-independent sequence analysis revealed a linkage pattern at two nucleotide positions that was unique to the genomes of isolates from patients, but not in C. trachomatis recombinants generated in vitro. These data demonstrated that culture-independent sequence analysis can be used to rapidly and inexpensively collect genome data from patients infected by C. trachomatis, and that this approach can be used to examine genomic variation within this species.
Collapse
Affiliation(s)
- Timothy E Putman
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR, USA
| | - Robert J Suchland
- Division of Allergy and Infectious Disease, Department of Medicine, University of Washington, Seattle, WA, USA
| | | | - Daniel D Rockey
- Department of Biomedical Sciences, Oregon State University, Corvallis, OR, USA
| |
Collapse
|
12
|
Jeffrey BM, Suchland RJ, Eriksen SG, Sandoz KM, Rockey DD. Genomic and phenotypic characterization of in vitro-generated Chlamydia trachomatis recombinants. BMC Microbiol 2013; 13:142. [PMID: 23786423 PMCID: PMC3703283 DOI: 10.1186/1471-2180-13-142] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 05/24/2013] [Indexed: 11/10/2022] Open
Abstract
Background Pre-genomic and post-genomic studies demonstrate that chlamydiae actively recombine in vitro and in vivo, although the molecular and cellular biology of this process is not well understood. In this study, we determined the genome sequence of twelve Chlamydia trachomatis recombinants that were generated in vitro under antibiotic selection. These strains were used to explore the process of recombination in Chlamydia spp., including analysis of candidate recombination hotspots, and to correlate known C. trachomatis in vitro phenotypes with parental phenotypes and genotypes. Results Each of the 190 examined recombination events was the product of homologous recombination, and no candidate targeting motifs were identified at recombination sites. There was a single deletion event in one recombinant progeny that resulted in the removal of 17.1 kilobases between two rRNA operons. There was no evidence for preference for any specific region of the chromosome for recombination, and analyses of a total of over 200 individual recombination events do not provide any support for recombination hotspots in vitro. Two measurable phenotypes were analyzed in these studies. First, the efficiency of attachment to host cells in the absence of centrifugation was examined, and this property segregated to regions of the chromosome that carry the polymorphic membrane protein (Pmp) genes. Second, the formation of secondary inclusions within cells varied among recombinant progeny, but this did not cleanly segregate to specific regions of the chromosome. Conclusions These experiments examined the process of recombination in C. trachomatis and identified tools that can be used to associate phenotype with genotype in recombinant progeny. There were no data supporting the hypothesis that particular nucleotide sequences are preferentially used for recombination in vitro. Selected phenotypes can be segregated by analysis of recombination, and this technology may be useful in preliminary analysis of the relationship of genetic variation to phenotypic variation in the chlamydiae.
Collapse
Affiliation(s)
- Brendan M Jeffrey
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR, USA
| | | | | | | | | |
Collapse
|
13
|
Xu JR, Bently J, Beck L, Reed A, Miller-Morgan T, Heidel JR, Kent ML, Rockey DD, Jin L. Analysis of koi herpesvirus latency in wild common carp and ornamental koi in Oregon, USA. J Virol Methods 2012; 187:372-9. [PMID: 23174162 DOI: 10.1016/j.jviromet.2012.11.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 10/31/2012] [Accepted: 11/05/2012] [Indexed: 11/26/2022]
Abstract
Koi herpesvirus (KHV) infection is associated with high mortalities in both common carp (Cyprinus carpio carpio) and koi carp (Cyprinus carpio koi) worldwide. Although acute infection has been reported in both domestic and wild common carp, the status of KHV latent infection is largely unknown in wild common carp. To investigate whether KHV latency is present in wild common carp, the distribution of KHV latent infection was investigated in two geographically distinct populations of wild common carp in Oregon, as well as in koi from an Oregon-based commercial supplier. Latent KHV infection was demonstrated in white blood cells from each of these populations. Although KHV isolated from acute infections has two distinct genetic groups, Asian and European, KHV detected in wild carp has not been genetically characterized. DNA sequences from ORF 25 to 26 that are unique between Asian and European were investigated in this study. KHV from captive koi and some wild common carp were found to have ORF-25-26 sequences similar to KHV-J (Asian), while the majority of KHV DNA detected in wild common carp has similarity to KHV-U/-I (European). In addition, DNA sequences from IL-10, and TNFR were sequenced and compared with no differences found, which suggests immune suppressor genes of KHV are conserved between KHV in wild common carp and koi, and is consistent with KHV-U, -I, -J.
Collapse
Affiliation(s)
- Jia-Rong Xu
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, United States
| | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Babra B, Watson G, Xu W, Jeffrey BM, Xu JR, Rockey DD, Rohrmann GF, Jin L. Analysis of the genome of leporid herpesvirus 4. Virology 2012; 433:183-91. [PMID: 22921533 DOI: 10.1016/j.virol.2012.08.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 07/16/2012] [Accepted: 08/01/2012] [Indexed: 10/28/2022]
Abstract
The genome of a herpesvirus highly pathogenic to rabbits, leporid herpesvirus 4 (LHV-4), was analyzed using high-throughput DNA sequencing technology and primer walking. The assembled DNA sequences were further verified by restriction endonuclease digestion and Southern blot analyses. The total length of the LHV-4 genome was determined to be about 124 kb. Genes encoded in the LHV-4 genome are most closely related to herpesvirus of the Simplexvirus genus, including human herpesviruses (HHV-1 and HHV-2), monkey herpesviruses including cercopithicine (CeHV-2 and CeHV-16), macacine (McHV-1), bovine herpesvirus 2 (BHV-2), and a lineage of wallaby (macropodid) herpesviruses (MaHV-1 and -2). Similar to other simplexvirus genomes, LHV-4 has a high overall G+C content of 65-70% in the unique regions and 75-77% in the inverted repeat regions. Orthologs of ICP34.5 and US5 were not identified in the LHV-4 genome. This study shows that LHV-4 has the smallest simplexvirus genome characterized to date.
Collapse
Affiliation(s)
- Bobby Babra
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Giacani L, Chattopadhyay S, Centurion-Lara A, Jeffrey BM, Le HT, Molini BJ, Lukehart SA, Sokurenko EV, Rockey DD. Footprint of positive selection in Treponema pallidum subsp. pallidum genome sequences suggests adaptive microevolution of the syphilis pathogen. PLoS Negl Trop Dis 2012; 6:e1698. [PMID: 22720110 PMCID: PMC3373638 DOI: 10.1371/journal.pntd.0001698] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 05/02/2012] [Indexed: 11/19/2022] Open
Abstract
In the rabbit model of syphilis, infection phenotypes associated with the Nichols and Chicago strains of Treponema pallidum (T. pallidum), though similar, are not identical. Between these strains, significant differences are found in expression of, and antibody responses to some candidate virulence factors, suggesting the existence of functional genetic differences between isolates. The Chicago strain genome was therefore sequenced and compared to the Nichols genome, available since 1998. Initial comparative analysis suggested the presence of 44 single nucleotide polymorphisms (SNPs), 103 small (≤3 nucleotides) indels, and 1 large (1204 bp) insertion in the Chicago genome with respect to the Nichols genome. To confirm the above findings, Sanger sequencing was performed on most loci carrying differences using DNA from Chicago and the Nichols strain used in the original T. pallidum genome project. A majority of the previously identified differences were found to be due to errors in the published Nichols genome, while the accuracy of the Chicago genome was confirmed. However, 20 SNPs were confirmed between the two genomes, and 16 (80.0%) were found in coding regions, with all being of non-synonymous nature, strongly indicating action of positive selection. Sequencing of 16 genomic loci harboring SNPs in 12 additional T. pallidum strains, (SS14, Bal 3, Bal 7, Bal 9, Sea 81-3, Sea 81-8, Sea 86-1, Sea 87-1, Mexico A, UW231B, UW236B, and UW249C), was used to identify "Chicago-" or "Nichols -specific" differences. All but one of the 16 SNPs were "Nichols-specific", with Chicago having identical sequences at these positions to almost all of the additional strains examined. These mutations could reflect differential adaptation of the Nichols strain to the rabbit host or pathoadaptive mutations acquired during human infection. Our findings indicate that SNPs among T. pallidum strains emerge under positive selection and, therefore, are likely to be functional in nature.
Collapse
Affiliation(s)
- Lorenzo Giacani
- Department of Medicine, University of Washington, Seattle, WA, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Abstract
Chlamydial plasmids are small, highly conserved, nonconjugative, and nonintegrative DNA molecules that are nearly ubiquitous in many chlamydial species, including Chlamydia trachomatis. There has been significant recent progress in understanding chlamydial plasmid participation in host-microbe interactions, disease, and immune responses. Work in mouse model systems and, very recently, in nonhuman primates demonstrates that plasmid-deficient chlamydial strains function as live attenuated vaccines against genital and ocular infections. Collectively, these studies open new avenues of research into developing vaccines against trachoma and sexually transmitted chlamydial infections.
Collapse
Affiliation(s)
- Daniel D Rockey
- Department of Biomedical Sciences, Oregon State University College of Veterinary Medicine, Corvallis, OR 97331, USA.
| |
Collapse
|
17
|
Beare PA, Sandoz KM, Omsland A, Rockey DD, Heinzen RA. Advances in genetic manipulation of obligate intracellular bacterial pathogens. Front Microbiol 2011; 2:97. [PMID: 21833334 PMCID: PMC3153054 DOI: 10.3389/fmicb.2011.00097] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 04/19/2011] [Indexed: 11/22/2022] Open
Abstract
Infections by obligate intracellular bacterial pathogens result in significant morbidity and mortality worldwide. These bacteria include Chlamydia spp., which causes millions of cases of sexually transmitted disease and blinding trachoma annually, and members of the α-proteobacterial genera Anaplasma, Ehrlichia, Orientia, and Rickettsia, agents of serious human illnesses including epidemic typhus. Coxiella burnetii, the agent of human Q fever, has also been considered a prototypical obligate intracellular bacterium, but recent host cell-free (axenic) growth has rescued it from obligatism. The historic genetic intractability of obligate intracellular bacteria has severely limited molecular dissection of their unique lifestyles and virulence factors involved in pathogenesis. Host cell restricted growth is a significant barrier to genetic transformation that can make simple procedures for free-living bacteria, such as cloning, exceedingly difficult. Low transformation efficiency requiring long-term culture in host cells to expand small transformant populations is another obstacle. Despite numerous technical limitations, the last decade has witnessed significant gains in genetic manipulation of obligate intracellular bacteria including allelic exchange. Continued development of genetic tools should soon enable routine mutation and complementation strategies for virulence factor discovery and stimulate renewed interest in these refractory pathogens. In this review, we discuss the technical challenges associated with genetic transformation of obligate intracellular bacteria and highlight advances made with individual genera.
Collapse
Affiliation(s)
- Paul A Beare
- Coxiella Pathogenesis Section, Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health Hamilton, MT, USA
| | | | | | | | | |
Collapse
|
18
|
Abstract
There are few documented reports of antibiotic resistance in Chlamydia and no examples of natural and stable antibiotic resistance in strains collected from humans. While there are several reports of clinical isolates exhibiting resistance to antibiotics, these strains either lost their resistance phenotype in vitro, or lost viability altogether. Differences in procedures for chlamydial culture in the laboratory, low recovery rates of clinical isolates and the unknown significance of heterotypic resistance observed in culture may interfere with the recognition and interpretation of antibiotic resistance. Although antibiotic resistance has not emerged in chlamydiae pathogenic to humans, several lines of evidence suggest they are capable of expressing significant resistant phenotypes. The adept ability of chlamydiae to evolve to antibiotic resistance in vitro is demonstrated by contemporary examples of mutagenesis, recombination and genetic transformation. The isolation of tetracycline-resistant Chlamydia suis strains from pigs also emphasizes their adaptive ability to acquire antibiotic resistance genes when exposed to significant selective pressure.
Collapse
Affiliation(s)
- Kelsi M Sandoz
- Molecular & Cellular Biology Program & the Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331–4804, USA
| | - Daniel D Rockey
- Molecular & Cellular Biology Program & the Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331–4804, USA
| |
Collapse
|
19
|
Abstract
The failure of the inactivated Chlamydia-based vaccine trials in the 1960s has led researchers studying Chlamydia to take cautious and rational approaches to develop safe and effective chlamydial vaccines. Subsequent research efforts focused on three areas. The first is the analysis of the immunobiology of chlamydial infection in animal models, with supporting clinical studies, to identify the immune correlates of both protective immunity and pathological responses. Second, recent radical improvements in genomics, proteomics and associated technologies have assisted in the implementation of creative approaches to search for suitable vaccine candidates. Third, progress in the analysis of host response and adjuvanticity regulating both innate and adaptive immunity at the mucosal site of infection has led to progress in the design of optimal delivery and adjuvant systems for enhancing protective immunity. Considerable progress has been made in the first two areas but research efforts to better define the factors that regulate immunity at mucosal sites of infection and to develop strategies to boost protective immunity via immunomodulation, effective delivery systems and potent adjuvants, have remained elusive. In this article, we will summarize progress in these areas with a focus on chlamydial vaccine antigen discovery, and discuss future directions towards the development of a safe and effective chlamydial vaccine.
Collapse
Affiliation(s)
- Daniel D Rockey
- Associate Professor, College of Veterinary Medicine, Oregon State University, 211 Dryden Hall, Corvallis, OR 97331-4804, USA.
| | | | | | | |
Collapse
|
20
|
Chu HG, Weeks SK, Gilligan DM, Rockey DD. Host alpha-adducin is redistributed and localized to the inclusion membrane in chlamydia- and chlamydophila-infected cells. Microbiology (Reading) 2009; 154:3848-3855. [PMID: 19047752 DOI: 10.1099/mic.0.2008/020941-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A large-scale analysis of proteins involved in host-cell signalling pathways was performed using chlamydia-infected murine cells in order to identify host proteins that are differentially activated or localized following infection. Two proteins whose distribution was altered in Chlamydia trachomatis-infected cells relative to mock-infected cells were the actin-binding protein adducin and the regulatory kinase Raf-1. Immunoblot analysis with antibodies to both phosphorylated and non-phosphorylated forms of these proteins demonstrated that the abundance of each protein was markedly reduced in the cytosolic fraction of C. trachomatis- and Chlamydophila caviae-infected cells, but the total cellular protein abundance remained unaffected by infection. Fluorescence microscopy of chlamydia-infected cells using anti-alpha-adducin antibodies demonstrated labelling at or near the chlamydial inclusion membrane. Treatment of infected cells with nocodazole or cytochalasin D did not affect alpha-adducin that was localized to the margins of the inclusion. The demonstration of alpha-adducin and Raf-1 redistribution within cells infected by different chlamydiae provides novel opportunities for analysis of host-pathogen interactions in this system.
Collapse
Affiliation(s)
- Hencelyn G Chu
- Department of Microbiology, Oregon State University, Corvallis, OR 97331-3804, USA
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331-4804, USA
| | - Sara K Weeks
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331-4804, USA
| | - Diana M Gilligan
- Puget Sound Blood Center, University of Washington, Seattle, WA 98104, USA
| | - Daniel D Rockey
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331-4804, USA
| |
Collapse
|
21
|
Alzhanov DT, Weeks SK, Burnett JR, Rockey DD. Cytokinesis is blocked in mammalian cells transfected with Chlamydia trachomatis gene CT223. BMC Microbiol 2009; 9:2. [PMID: 19123944 PMCID: PMC2657910 DOI: 10.1186/1471-2180-9-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Accepted: 01/05/2009] [Indexed: 01/07/2023] Open
Abstract
Background The chlamydiae alter many aspects of host cell biology, including the division process, but the molecular biology of these alterations remains poorly characterized. Chlamydial inclusion membrane proteins (Incs) are likely candidates for direct interactions with host cell cytosolic proteins, as they are secreted to the inclusion membrane and exposed to the cytosol. The inc gene CT223 is one of a sequential set of orfs that encode or are predicted to encode Inc proteins. CT223p is localized to the inclusion membrane in all tested C. trachomatis serovars. Results A plasmid transfection approach was used to examine the function of the product of CT223 and other Inc proteins within uninfected mammalian cells. Fluorescence microscopy was used to demonstrate that CT223, and, to a lesser extent, adjacent inc genes, are capable of blocking host cell cytokinesis and facilitating centromere supranumeracy defects seen by others in chlamydiae-infected cells. Both phenotypes were associated with transfection of plasmids encoding the carboxy-terminal tail of CT223p, a region of the protein that is likely exposed to the cytosol in infected cells. Conclusion These studies suggest that certain Inc proteins block cytokinesis in C. trachomatis-infected cells. These results are consistent with the work of others showing chlamydial inhibition of host cell cytokinesis.
Collapse
Affiliation(s)
- Damir T Alzhanov
- Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA.
| | | | | | | |
Collapse
|
22
|
Dugan J, Andersen AA, Rockey DD. Functional characterization of IScs605, an insertion element carried by tetracycline-resistant Chlamydia suis. Microbiology (Reading) 2007; 153:71-9. [PMID: 17185536 DOI: 10.1099/mic.0.29253-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Stable tetracycline resistance in Chlamydia suis is mediated by a family of genomic islands [the tet(C) islands] that are integrated into the chlamydial chromosome. The tet(C) islands contain several plasmid-specific genes, the tet(C) resistance gene and, in most cases, a novel insertion element (IScs605) encoding two predicted transposases. The hypothesis that IScs605 mediated the integration of the tet(C) resistance islands into the C. suis genome was tested using a plasmid-based transposition system in Escherichia coli. Both high- and medium-copy-number plasmids were used as carriers of IScs605 in these experiments. IScs605 integrated into a target plasmid (pOX38) when delivered by either donor plasmid, and integration of the entire donor plasmid was common. IScs605-mediated integration occurred at many positions within pOX38, with 36 of 38 events adjacent to a 5'-TTCAA-3' sequence. Deletions in each of the candidate transposase genes within IScs605 demonstrated that only one of the two ORFs was necessary for the observed transposition activity and target specificity. Analysis of progeny from the mating assays also indicated that IScs605 can excise following integration into a target DNA, and, in each tested case, the sequence 5'-AATTCAA-3' remained at the site of excision. Collectively, these results are consistent with the nucleotide sequence data collected for the tet(C) islands, and strongly suggest that a transposase within IScs605 is responsible for integration of these genomic islands into the C. suis chromosome.
Collapse
Affiliation(s)
- Jae Dugan
- Department of Biomedical Sciences, College of Veterinary Medicine and the Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR 97331, USA
| | | | | |
Collapse
|
23
|
Alzhanov DT, Suchland RJ, Bakke AC, Stamm WE, Rockey DD. Clonal isolation of chlamydia-infected cells using flow cytometry. J Microbiol Methods 2007; 68:201-8. [PMID: 16997404 DOI: 10.1016/j.mimet.2006.07.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Revised: 07/17/2006] [Accepted: 07/24/2006] [Indexed: 11/20/2022]
Abstract
This manuscript describes a new technique for the microbiological cloning of chlamydia-infected cells using a fluorescence activated cell sorter (FACS). The approach exploits chlamydial acquisition of the fluorescent, Golgi-specific, stain 6-((N-7-(-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-hexanoyl)sphingosine (C6-NBD-cer). This fluorescent lipid is delivered from the Golgi apparatus to the chlamydial inclusion membrane and then to the developmental forms within the inclusion in living, infected cells. Labeling with C6-NBD-cer results in easily identifiable chlamydial inclusions that can then be analyzed and sorted by FACS. This technique was used successfully to sort individual chlamydia-infected cells into individual wells of a culture dish and, in this experimental system, resulted in the isolation of cloned chlamydial isolates. FACS-based sorting was used to isolate clonal populations of prototype strains from Chlamydia trachomatis, C. caviae and C. suis. Recent clinical isolates were also successfully cloned using FACS. The procedure is simple and rapid, with single cloning cycles being completed 24 h post-culture of a sample. It is anticipated that FACS-based sorting of live chlamydia-infected cells will be a significant technical tool for the isolation of clonal populations of any chlamydial strain.
Collapse
Affiliation(s)
- Damir T Alzhanov
- Department of Microbiology, College of Science, Oregon State University, Corvallis, OR 97331, USA
| | | | | | | | | |
Collapse
|
24
|
Xia M, Suchland RJ, Bumgarner RE, Peng T, Rockey DD, Stamm WE. Chlamydia trachomatis variant with nonfusing inclusions: growth dynamic and host-cell transcriptional response. J Infect Dis 2005; 192:1229-36. [PMID: 16136466 DOI: 10.1086/444394] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2005] [Accepted: 04/28/2005] [Indexed: 11/04/2022] Open
Abstract
We compared growth rate and host-cell transcriptional responses of a Chlamydia trachomatis variant strain and a prototype strain. Growth dynamics were estimated by 16S rRNA level and by inclusion-forming units (IFUs) at different times after infection in HeLa cells. When inoculated at the same multiplicity of infection and observed 24-48 h after infection, the variant 16S rRNA transcriptional level was 3%-4% that of the prototype, and the IFUs of the variant strain were 0.1%-1% those of the prototype. Specific host-cell transcriptional responses to the variant were identified in a global-expression microarray in which variant strain-infected cells were compared with mock-infected and prototype strain-infected cells. In variant strain-infected cells, 47% (16/34) of specifically induced host genes were related to immunity and 32% (8/25) of specifically suppressed genes were related to lipid metabolism. The variant strain grew significantly more slowly and induced a modified host-cell transcriptional response, compared with the prototype strain.
Collapse
Affiliation(s)
- Minsheng Xia
- Division of Infectious Diseases, Department of Medicine, University of Washington, Seattle, USA
| | | | | | | | | | | |
Collapse
|
25
|
Abstract
The chlamydiae are obligate intracellular bacteria that occupy a non-acidified vacuole (the inclusion) during their entire developmental cycle. These bacteria produce a set of proteins (Inc proteins) that localize to the surface of the inclusion within infected cells. Chlamydia trachomatis IncA is also commonly found in long fibers that extend away from the inclusion. We used standard and confocal immunofluorescence microscopy to demonstrate that these fibers extend to newly developed inclusions, termed secondary inclusions, within infected cells. Secondary inclusions observed at early time points postinfection were devoid of chlamydial reticulate bodies. Later in the developmental cycle, secondary inclusions containing variable numbers of reticulate bodies were common. Reticulate bodies were also observed within the IncA-laden fibers connecting primary and secondary inclusions. Quantitative differences in secondary inclusion formation were found among clinical isolates, and these differences were associated with serovar. Isolates of serovar G consistently produced secondary inclusions at the highest frequency (P < 0.0001). Similar quantitative studies demonstrated that secondary inclusion formation was associated with segregation of inclusions to daughter cells following cytokinesis. We conclude that the production of secondary inclusions via IncA-laden fibers allows chlamydiae to generate an expanded intracellular niche in which they can grow and may provide a means for continuous infection within progeny cells following cell division.
Collapse
Affiliation(s)
- Robert J Suchland
- Division of Allergy and Infectious Diseases, School of Medicine, University of Washington, Seattle 98105, USA
| | | | | | | | | |
Collapse
|
26
|
Dugan J, Rockey DD, Jones L, Andersen AA. Tetracycline resistance in Chlamydia suis mediated by genomic islands inserted into the chlamydial inv-like gene. Antimicrob Agents Chemother 2004; 48:3989-95. [PMID: 15388463 PMCID: PMC521927 DOI: 10.1128/aac.48.10.3989-3995.2004] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Many strains of Chlamydia suis, a pathogen of pigs, express a stable tetracycline resistance phenotype. We demonstrate that this resistance pattern is associated with a resistance gene, tet(C), in the chlamydial chromosome. Four related genomic islands were identified in seven tetracycline-resistant C. suis strains. All resistant isolates carry the structural gene tet(C) and the tetracycline repressor gene tetR(C). The islands share significant nucleotide sequence identity with resistance plasmids carried by a variety of different bacterial species. Three of the four tet(C) islands also carry a novel insertion sequence that is homologous to the IS605 family of insertion sequences. In each strain, the resistance gene and associated sequences are recombined into an identical position in a gene homologous to the inv gene of the yersiniae. These genomic islands represent the first examples of horizontally acquired DNA integrated into a natural isolate of chlamydiae or within any other obligate intracellular bacterium.
Collapse
Affiliation(s)
- Jae Dugan
- Department of Biomedical Sciences, Oregon State University, 106 Dryden Hall, Corvallis, OR 97331-4804, USA.
| | | | | | | |
Collapse
|
27
|
Alzhanov D, Barnes J, Hruby DE, Rockey DD. Chlamydial development is blocked in host cells transfected with Chlamydophila caviae incA. BMC Microbiol 2004; 4:24. [PMID: 15230981 PMCID: PMC459217 DOI: 10.1186/1471-2180-4-24] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2004] [Accepted: 07/01/2004] [Indexed: 11/29/2022] Open
Abstract
Background Chlamydiae produce a set of proteins, termed Inc proteins, that are localized to the inclusion membrane and exposed to the host cell cytosol. Little information exists regarding the interaction of Inc proteins with the eukaryotic cell. To examine these interactions, Vaccinia virus vectors and mammalian plasmid-based systems were used to express inc genes in mammalian cells. Results Cells transfected with plasmids expressing Chlamydophila caviae incA were not productively infected by C. caviae. Expression of C. caviae incA also reduced inclusion formation by Chlamydia trachomatis, but not to the degree seen for C. caviae. Chlamydia trachomatis incA did not block development of either C. trachomatis or C. caviae. Deletion mutagenesis was used to demonstrate that plasmids encoding either the amino or carboxy-terminal regions of the protein, as well as the changing of a single amino acid within IncA (serine 17) could not block C. caviae infection. Immunoblot analysis of truncated IncA in a Vaccinia virus system provided evidence that serine 17 of C. caviae IncA is a target for phosphorylation. Conclusions These experiments provide insight into the interaction of Inc proteins with the host cell and introduce a model system where these interactions can be explored further.
Collapse
Affiliation(s)
- Damir Alzhanov
- Department of Microbiology, Oregon State University, Corvallis, OR 97331-3804 USA
| | - Jennifer Barnes
- Department of Microbiology, Oregon State University, Corvallis, OR 97331-3804 USA
- Roche Diagnostics NZ Ltd, Molecular Diagnostics and Applied Science, PO Box 13941, Onehunga Auckland, New Zealand
| | - Dennis E Hruby
- Department of Microbiology, Oregon State University, Corvallis, OR 97331-3804 USA
| | - Daniel D Rockey
- Department of Microbiology, Oregon State University, Corvallis, OR 97331-3804 USA
| |
Collapse
|
28
|
Viratyosin W, Campbell LA, Kuo CC, Rockey DD. Intrastrain and interstrain genetic variation within a paralogous gene family in Chlamydia pneumoniae. BMC Microbiol 2002; 2:38. [PMID: 12460455 PMCID: PMC140016 DOI: 10.1186/1471-2180-2-38] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2002] [Accepted: 12/02/2002] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chlamydia pneumoniae causes human respiratory diseases and has recently been associated with atherosclerosis. Analysis of the three recently published C. pneumoniae genomes has led to the identification of a new gene family (the Cpn 1054 family) that consists of 11 predicted genes and gene fragments. Each member encodes a polypeptide with a hydrophobic domain characteristic of proteins localized to the inclusion membrane. RESULTS Comparative analysis of this gene family within the published genome sequences provided evidence that multiple levels of genetic variation are evident within this single collection of paralogous genes. Frameshift mutations are found that result in both truncated gene products and pseudogenes that vary among isolates. Several genes in this family contain polycytosine (polyC) tracts either upstream or within the terminal 5' end of the predicted coding sequence. The length of the polyC stretch varies between paralogous genes and within single genes in the three genomes. Sequence analysis of genomic DNA from a collection of 12 C. pneumoniae clinical isolates was used to determine the extent of the variation in the Cpn 1054 gene family. CONCLUSIONS These studies demonstrate that sequence variability is present both among strains and within strains at several of the loci. In particular, changes in the length of the polyC tract associated with the different Cpn 1054 gene family members are common within each tested C. pneumoniae isolate. The variability identified within this newly described gene family may modulate either phase or antigenic variation and subsequent physiologic diversity within a C. pneumoniae population.
Collapse
Affiliation(s)
- Wasna Viratyosin
- Department of Microbiology, Oregon State University, Corvallis, 97331-3804, USA
- Present Address: National Center for Genetic Engineering and Biotechnology, 113 Paholyothin Rd., Klong 1, Klong Luang, Pathumthani 12120, Thailand
| | - Lee Ann Campbell
- Department of Pathobiology, University of Washington, Seattle, 98195, USA
| | - Cho-Chou Kuo
- Department of Pathobiology, University of Washington, Seattle, 98195, USA
| | - Daniel D Rockey
- Department of Microbiology, Oregon State University, Corvallis, 97331-3804, USA
| |
Collapse
|
29
|
Brown WJ, Skeiky YAW, Probst P, Rockey DD. Chlamydial antigens colocalize within IncA-laden fibers extending from the inclusion membrane into the host cytosol. Infect Immun 2002; 70:5860-4. [PMID: 12228318 PMCID: PMC128327 DOI: 10.1128/iai.70.10.5860-5864.2002] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chlamydial IncA localizes to the inclusion membrane and to vesicular fibers extending away from the inclusion. Chlamydial outer membrane components, in the absence of developmental forms, are found within these fibers. This colocalization may explain how chlamydial developmental form antigens are localized outside of the inclusion within infected cells.
Collapse
Affiliation(s)
- W J Brown
- Department of Microbiology, Oregon State University, Corvallis, Oregon 97331, USA
| | | | | | | |
Collapse
|
30
|
Rockey DD, Viratyosin W, Bannantine JP, Suchland RJ, Stamm WE. Diversity within inc genes of clinical Chlamydia trachomatis variant isolates that occupy non-fusogenic inclusions. Microbiology (Reading) 2002; 148:2497-2505. [PMID: 12177343 DOI: 10.1099/00221287-148-8-2497] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The obligately intracellular chlamydiae are bacterial pathogens that occupy intracellular vacuoles, termed inclusions, as they develop and multiply. Typical Chlamydia trachomatis isolates occupy inclusions that fuse with other C. trachomatis inclusions within cells infected with multiple elementary bodies (wild-type phenotype). The authors of this study have recently described C. trachomatis isolates that form multiply-lobed, non-fusogenic inclusions within single cells infected with multiple elementary bodies (variant phenotype). Inclusions formed by these isolates uniformly lacked the protein IncA on the inclusion membrane (IM). In the present work, the study of the C. trachomatis inclusion phenotype has been expanded to include 27 variant and 13 wild-type isolates. Twenty-four of the 27 variant isolates were IncA-negative, as detected by fluorescence microscopy and immunoblotting, but three variants localized IncA to the IM. The IncA-positive variants formed inclusions that fused, at a reduced rate, with those occupied by wild-type isolates and with inclusions formed by other IncA-positive variants. Nucleotide-sequence analysis of the incA sequences from the variant isolates identified a variety of distinct sequence polymorphisms relative to incA from wild-type strains. The authors also demonstrate that a second Inc protein, CT223p, is not found in the IM in selected C. trachomatis isolates. No change in the structure or the fusogenicity of the inclusions was associated with the presence or absence of CT223p.
Collapse
Affiliation(s)
- Daniel D Rockey
- Department of Microbiology, Oregon State University, Corvallis OR 97331-3804, USA1
| | - Wasna Viratyosin
- Department of Microbiology, Oregon State University, Corvallis OR 97331-3804, USA1
| | | | - Robert J Suchland
- Division of Allergy and Infectious Diseases, School of Medicine, University of Washington, Seattle, WA 98195, USA3
| | - Walter E Stamm
- Division of Allergy and Infectious Diseases, School of Medicine, University of Washington, Seattle, WA 98195, USA3
| |
Collapse
|
31
|
Abstract
The chlamydiae are obligate intracellular pathogens that occupy a nonacidified vacuole (the inclusion) during their entire developmental cycle. Several proteins have recently been identified that are localized to the inclusion membrane. The following is a discussion of how inclusion membrane proteins might participate in the chlamydial developmental process.
Collapse
Affiliation(s)
- Daniel D Rockey
- Department of Microbiology, Oregon State University, Corvallis, OR 97331-3804, USA.
| | | | | | | |
Collapse
|
32
|
Geisler WM, Suchland RJ, Rockey DD, Stamm WE. Epidemiology and clinical manifestations of unique Chlamydia trachomatis isolates that occupy nonfusogenic inclusions. J Infect Dis 2001; 184:879-84. [PMID: 11528595 DOI: 10.1086/323340] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2001] [Revised: 06/08/2001] [Indexed: 11/03/2022] Open
Abstract
Unique Chlamydia trachomatis strains characterized by multiple nonfusing inclusions were recently described. These strains lack evidence of the protein IncA in the inclusion membrane and have mutations in the incA gene. This study evaluated the epidemiology and clinical manifestations of patients infected with nonfusing mutant strains (case patients) and compared them with patients infected with wild-type fusing strains (control subjects). Both male and female case patients had fewer signs of infection than did control subjects (P=.016 and P=.019, respectively). Female case patients also had fewer symptoms of infection (P=.02). Median inclusion-forming unit (ifu) counts were lower in male and female case patients (P=.045 and P=.135, respectively). Thus, nonfusing strains of C. trachomatis more often produce subclinical infections than do normal fusing strains and have lower median ifu counts. From a prevention perspective, the data underscore the importance of screening programs to detect and treat inapparent C. trachomatis infection.
Collapse
Affiliation(s)
- W M Geisler
- Division of Allergy and Infectious Diseases, School of Medicine, University of Washington, Seattle 98195, Washington, USA.
| | | | | | | |
Collapse
|
33
|
Abstract
Tetracycline (TET) is a front-line antibiotic for the treatment of chlamydial infections in both humans and animals, and the emergence of TET-resistant (Tet(r)) Chlamydia is of significant clinical importance. Recently, several Tet(r) chlamydial strains have been isolated from swine (Sus scrofa) raised in production facilities in Nebraska. Here, the intracellular development of two Tet(r) strains, R19 and R27, is characterized through the use of tissue culture and immunofluorescence. The strains grow in concentrations of up to 4 microg of TET/ml, while a TET-sensitive (Tet(s)) swine strain (S45) and a strain of the human serovar L2 (LGV-434) grow in up to 0.1 microg of TET/ml. Although inclusions form in the presence of TET, many contain large aberrant reticulate bodies (RBs) that do not differentiate into infectious elementary bodies. The percentage of inclusions containing typical developmental forms decreases with increasing TET concentrations, and at 3 microg of TET/ml 100% of inclusions contain aberrant RBs. However, upon removal of TET the aberrant RBs revert to typical RBs, and a productive developmental cycle ensues. In addition, inclusions were found that contained both C. suis R19 and Chlamydia trachomatis L2 after sequential infection, demonstrating that two biologically distinct chlamydial strains could both develop within a single inclusion.
Collapse
Affiliation(s)
- J Lenart
- Department of Microbiology, Oregon State University, Corvallis, Oregon 97331, USA
| | | | | |
Collapse
|
34
|
Affiliation(s)
- D D Rockey
- Department of Microbiology, Oregon State University, Corvallis, Oregon 97331-3804, USA.
| | | | | |
Collapse
|
35
|
Bannantine JP, Griffiths RS, Viratyosin W, Brown WJ, Rockey DD. A secondary structure motif predictive of protein localization to the chlamydial inclusion membrane. Cell Microbiol 2000; 2:35-47. [PMID: 11207561 DOI: 10.1046/j.1462-5822.2000.00029.x] [Citation(s) in RCA: 184] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Chlamydiae are obligate intracellular pathogens that spend their entire growth phase sequestered in a membrane-bound vacuole called an inclusion. A set of chlamydial proteins, labelled Inc proteins, has been identified in the inclusion membrane (IM). The predicted IncA, IncB and IncC amino acid sequences share very limited similarity, but a common hydrophobicity motif is present within each Inc protein. In an effort to identify a relatively complete catalogue of Chlamydia trachomatis proteins present in the IM of infected cells, we have screened the genome for open reading frames encoding this structural motif. Hydropathy plot analysis was used to screen each translated open reading frame in the C. trachomatis genome database. Forty-six candidate IM proteins (C-lncs) that satisfied the criteria of containing a bilobed hydrophobic domain of at least 50 amino acids were identified. The genome of Chlamydia pneumoniae encodes a larger collection of C-lnc proteins, and only approximately half of the C-lncs are encoded within both genomes. In order to confirm the hydropathy plot screening method as a valid predictor of C-lncs, antisera and/or monoclonal antibodies were prepared against six of the C. trachomatis C-lncs. Immunofluorescence microscopy of C. trachomatis-infected cells probed with these antibodies showed that five out of six C-lncs are present in the chlamydial IM. Antisera were also produced against C. pneumoniae p186, a protein sharing identity with Chlamydia psittaci lncA and carrying a similar bilobed hydrophobic domain. These antisera labelled the inclusion membrane in C. pneumoniae infected cells, confirming that proteins sharing the unique secondary structural characteristic also localize to the inclusion membrane of C. pneumoniae. Sera from patients with high-titre antibodies to C. trachomatis were examined for reactivity with each tested C-lnc protein. Three out of six tested C-lncs were recognized by a majority of these patient sera. Collectively, these studies identify and characterize novel proteins localized to the chlamydial IM and demonstrate the existence of a potential secondary structural targeting motif for localization of chlamydial proteins to this unique intracellular environment.
Collapse
Affiliation(s)
- J P Bannantine
- Department of Microbiology, Oregon State University, Corvallis 97331-3804, USA
| | | | | | | | | |
Collapse
|
36
|
Abstract
The process of chlamydial cell division has not been thoroughly investigated. The lack of detectable peptidoglycan and the absence of an FtsZ homolog within chlamydiae suggest an unusual mechanism for the division process. Our laboratory has identified an antigen (SEP antigen) localized to a ring-like structure at the apparent septum within dividing chlamydial reticulate bodies (RB). Antisera directed against SEP show similar patterns of antigen distribution in Chlamydia trachomatis and Chlamydia psittaci RB. In contrast to localization in RB, SEP in elementary bodies appears diffuse and irregular, suggesting that the distribution of the antigen is developmental-stage specific. Treatment of chlamydiae with inhibitors of peptidoglycan synthesis or culture of chlamydiae in medium lacking tryptophan leads to the formation of nondividing, aberrant RB. Staining of aberrant RB with anti-SEP reveals a marked redistribution of the antigen. Within C. trachomatis-infected cells, ampicillin treatment leads to high levels of SEP accumulation at the periphery of aberrant RB, while in C. psittaci, treatment causes SEP to localize to distinct punctate sites within the bacteria. Aberrancy produced via tryptophan depletion results in a different pattern of SEP distribution. In either case, the reversal of aberrant formation results in the production of normal RB and a redistribution of SEP to the apparent plane of bacterial division. Collectively these studies identify a unique chlamydial-genus-common and developmental-stage-specific antigen that may be associated with RB division.
Collapse
Affiliation(s)
- W J Brown
- Department of Microbiology, Oregon State University, Corvallis, Oregon 97331-3804, USA
| | | |
Collapse
|
37
|
Suchland RJ, Rockey DD, Bannantine JP, Stamm WE. Isolates of Chlamydia trachomatis that occupy nonfusogenic inclusions lack IncA, a protein localized to the inclusion membrane. Infect Immun 2000; 68:360-7. [PMID: 10603409 PMCID: PMC97142 DOI: 10.1128/iai.68.1.360-367.2000] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The chlamydiae are obligate intracellular pathogens that occupy a nonacidified vacuole, termed an inclusion, throughout their developmenal cycle. When an epithelial cell is infected with multiple Chlamydia trachomatis elementary bodies, they are internalized by endocytosis into individual phagosomal vacuoles that eventually fuse to form a single inclusion. In the course of large-scale serotyping studies in which fluorescent antibody staining of infected cells was used, a minority of strains that had an alternate inclusion morphology were identified. These variants formed multiple nonfusogenic inclusions in infected cells, with the number of independent inclusions per cell varying directly with the multiplicity of infection. Overall the nonfusogenic phenotype was found in 1.5% (176 of 11,440) of independent isolates. Nonfusing variants were seen in C. trachomatis serovars B, D, D-, E, F, G, H, Ia, J, and K. The nonfusing phenotype persisted through repeated serial passage, and the phenotype was consistent in four mammalian host cell lines. Fluorescence microscopy and immunoblotting with antisera directed at proteins in the C. trachomatis inclusion membrane revealed that one such protein, IncA, was not detected in the inclusion membrane in each tested nonfusogenic strain. The distributions of other chlamydial proteins, including one additional Inc protein, were similar in wild-type and variant strains. The incA coding and upstream regions were amplified and sequenced from the prototype serovar D and two nonfusing serovar D((s)) strains. Three nucleotide changes were discovered in the D((s)) incA gene, leading to two amino acid changes within the predicted D((s)) IncA sequence. These studies demonstrate a subgroup of variant C. trachomatis isolates that form nonfusing inclusions; the variant phenotype is associated with the absence of detectable IncA and with an altered incA sequence that modifies the characteristic hydrophobic domain of the IncA protein.
Collapse
Affiliation(s)
- R J Suchland
- Division of Allergy and Infectious Diseases, School of Medicine, University of Washington, Seattle, Washington, USA.
| | | | | | | |
Collapse
|
38
|
Bannantine JP, Rockey DD. Use of primate model system to identify Chlamydia trachomatis protein antigens recognized uniquely in the context of infection. Microbiology (Reading) 1999; 145 ( Pt 8):2077-2085. [PMID: 10463174 DOI: 10.1099/13500872-145-8-2077] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
A primate model system was used to identify Chlamydia trachomatis antigens uniquely recognized in the context of infection. Serum antibody titres were measured in cynomolgus monkeys challenged urethrally with C. trachomatis serovar L2 elementary bodies (EBs). High-titre sera from these primates were used, in parallel with antisera against killed C. trachomatis EBs, to differentially screen an expression library of C. trachomatis serovar L2 DNA. Four clones were recognized only by antisera from infected monkeys. Sequence analysis revealed that three of these immunoreactive clones overlap a common ORF, designated ORF D242 (encoding p242), in the C. trachomatis genome database. The fourth clone contains two complete ORFs, each encoding 32 kDa proteins that share identity with Treponema pallidum TroA and TroB (ORFs D067 and D068 in the C. trachomatis database, respectively). Immunoblot analysis of Escherichia coli lysates expressing C. trachomatis TroA, TroB and p242 fusion proteins showed that p242 and TroA, but not TroB, were detected by the sera collected from infected primates. Antibodies directed at TroA and p242 were also detected in sera from several C. trachomatis-infected patients, demonstrating that these proteins are also recognized by humans following infection. Immunoblot analysis with antibody against TroA and p242 also demonstrated that both antigens are present in higher abundance in infected ChoK1 cells relative to purified C. trachomatis EBs. Immunofluorescence microscopy shows that TroA and p242 are both localized to intracellular developmental forms at the margins of growing inclusions. Collectively, these studies identify two C. trachomatis proteins that are under-represented in EBs and are recognized uniquely in the context of infection.
Collapse
|
39
|
Bannantine JP, Stamm WE, Suchland RJ, Rockey DD. Chlamydia trachomatis IncA is localized to the inclusion membrane and is recognized by antisera from infected humans and primates. Infect Immun 1998; 66:6017-21. [PMID: 9826388 PMCID: PMC108764 DOI: 10.1128/iai.66.12.6017-6021.1998] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/1998] [Accepted: 09/11/1998] [Indexed: 11/20/2022] Open
Abstract
Chlamydia psittaci produces a collection of proteins, termed IncA, IncB, and IncC, that are localized to the chlamydial inclusion membrane. In this report we demonstrate that IncA is also produced by Chlamydia trachomatis. C. trachomatis IncA is structurally similar to C. psittaci IncA and is also localized to the inclusion membrane. Immunoblot analysis demonstrated that sera from C. trachomatis-infected patients and from experimentally infected monkeys both recognized C. trachomatis IncA.
Collapse
Affiliation(s)
- J P Bannantine
- Department of Microbiology, Oregon State University, Corvallis, Oregon 97331-3804, USA
| | | | | | | |
Collapse
|
40
|
Abstract
Chlamydiae are obligate intracellular bacteria that replicate within a non-acidified vacuole, termed an inclusion. To identify chlamydial proteins that are unique to the intracellular phase of the life cycle, a lambda expression library of Chlamydia psittaci DNA was differentially screened with convalescent antisera from infected guinea pigs and antisera directed at formalin-fixed purified chlamydial elementary bodies (EBs). One library clone was identified that harboured two open reading frames (ORFs) with coding potential for similar-sized proteins of approximately 20 kDa. These proteins were subsequently termed IncB and IncC. Sequencing of the cloned insert revealed a strong Escherichia coli-like promoter sequence immediately upstream of incB and a 36nt intergenic region between the ORFs. Sequence analysis of the region upstream of incB and incC revealed two ORFs that had strong homologies to an amino acid transporter and a sodium-dependent transporter. Immunoblotting with antisera directed at IncB or IncC demonstrated that these proteins are present in C. psittaci-infected HeLa cells but are absent or below the level of detection in purified EBs. Reverse transcriptase-polymerase chain reactions provided evidence that incB and incC are transcribed in an operon. Immunofluorescence microscopy demonstrated that IncB and IncC are each localized to the inclusion membrane of infected cells. No primary sequence similarity is evident between IncA, IncB or IncC, but each contains a large hydrophobic domain of similar size and character as in IncA. Analysis of the recently completed C. trachomatis serovar D genome database has revealed C. trachomatis ORFs encoding homologues to incB and incC, indicating that these genes are conserved among the chlamydiae.
Collapse
Affiliation(s)
- J P Bannantine
- Department of Microbiology, Oregon State University, Corvallis 97331-3804, USA
| | | | | |
Collapse
|
41
|
Abstract
Chlamydiae dissociate themselves from the endocytic pathway shortly after internalization by actively modifying the vacuole to become fusogenic with sphingomyelin-containing exocytic vesicles. Interaction with this secretory pathway appears to provide a pathogenic mechanism that allows chlamydiae to establish themselves in a site that is not destined to fuse with lysosomes.
Collapse
Affiliation(s)
- T Hackstadt
- Host-Parasite Interactions Section, National Institute of Allergy and Infections Diseases, NIH, Rocky Mountain Laboratories, Hamilton, MT 59840, USA.
| | | | | | | | | |
Collapse
|
42
|
Rockey DD, Grosenbach D, Hruby DE, Peacock MG, Heinzen RA, Hackstadt T. Chlamydia psittaci IncA is phosphorylated by the host cell and is exposed on the cytoplasmic face of the developing inclusion. Mol Microbiol 1997; 24:217-28. [PMID: 9140978 DOI: 10.1046/j.1365-2958.1997.3371700.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Chlamydiae are obligate intracellular bacteria that replicate within a non-acidified vacuole called an inclusion. Chlamydia psittaci (strain GPIC) produces a 39 kDa protein (IncA) that is localized to the inclusion membrane. While IncA is present as a single 39 kDa species in purified reticulate bodies, two additional higher M(r) forms are found in C. psittaci-infected cells. This finding suggested that IncA may be post-translationally modified in the host cell. Here we present evidence that IncA is a serine/threonine phosphoprotein that is phosphorylated by host cell enzymes. This conclusion is supported by the following experimental findings: (i) treatment of infected cells with inhibitors of host cell phosphatases or kinases altered the electrophoretic migration pattern of IncA; (ii) treatment with calf intestinal alkaline phosphatase eliminated the multiple-banding pattern of IncA, leaving only the protein band with the lowest relative molecular weight; and (iii) radioimmunoprecipitation of lysates of [32P]-orthophosphate-labelled infected HeLa cells with anti-IncA antisera demonstrated that the two highest M(r) IncA bands were phosphorylated. A vaccinia-virus recombinant expressing incA was used to determine if HeLa cells can phosphorylate IncA in the absence of a chlamydial background. IncA in lysates of these cells migrated identically to that seen in C. psittaci-infected cells, indicating the host cell was responsible for the phosphorylation of the protein. Microinjection of fluorescently labelled anti-IncA antibodies into C. psittaci-infected HeLa cells resulted in immunostaining of the outer face of the inclusion membrane. Collectively, these results demonstrate that IncA is phosphorylated by the host cell, and regions of IncA are exposed at the cytoplasmic face of the inclusion.
Collapse
Affiliation(s)
- D D Rockey
- Rocky Mountain Laboratories, NIH, NIAID Hamilton, Montana 59840, USA.
| | | | | | | | | | | |
Collapse
|
43
|
Scidmore MA, Rockey DD, Fischer ER, Heinzen RA, Hackstadt T. Vesicular interactions of the Chlamydia trachomatis inclusion are determined by chlamydial early protein synthesis rather than route of entry. Infect Immun 1996; 64:5366-72. [PMID: 8945589 PMCID: PMC174531 DOI: 10.1128/iai.64.12.5366-5372.1996] [Citation(s) in RCA: 132] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Chlamydiae replicate intracellularly within a vacuole that has recently been characterized as intersecting an exocytic pathway. One of the initial events during chlamydial infection is the expression of a chlamydial early gene product(s) that effectively isolates the inclusion from the endocytic-lysosomal pathway and makes it fusogenic with sphingomyelin-containing exocytic vesicles. Associated with this change in vesicular interaction is the delivery of the vacuole to the peri-Golgi region of the host cell. Inhibition of chlamydial early transcription or translation causes Chlamydia trachomatis-containing vesicles to remain dispersed throughout the cytoplasm, where they eventually fuse with lysosomes. Chlamydiae that have been internalized by Fc-mediated endocytosis also avoid lysosomal digestion by a mechanism that requires chlamydial protein synthesis. These results suggest that the vesicular interactions of the chlamydial inclusion are defined by parasite-directed modification of the endocytic vesicle rather than by the route of internalization.
Collapse
Affiliation(s)
- M A Scidmore
- Laboratory of Intracellular Parasites, National Institute of Allergy and Infectious Diseases, Rocky Mountain Laboratories, Hamilton, Montana 59840, USA
| | | | | | | | | |
Collapse
|
44
|
Su H, Raymond L, Rockey DD, Fischer E, Hackstadt T, Caldwell HD. A recombinant Chlamydia trachomatis major outer membrane protein binds to heparan sulfate receptors on epithelial cells. Proc Natl Acad Sci U S A 1996; 93:11143-8. [PMID: 8855323 PMCID: PMC38298 DOI: 10.1073/pnas.93.20.11143] [Citation(s) in RCA: 126] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Chlamydial attachment to columnar conjunctival or urogenital epithelial cells is an initial and critical step in the pathogenesis of chlamydial mucosal infections. The chlamydial major outer membrane protein (MOMP) has been implicated as a putative chlamydial cytoadhesin; however, direct evidence supporting this hypothesis has not been reported. The function of MOMP as a cytoadhesin was directly investigated by expressing the protein as a fusion with the Escherichia coli maltose binding protein (MBP-MOMP) and studying its interaction with human epithelial cells. The recombinant MBP-MOMP bound specifically to HeLa cells at 4 degrees C but was not internalized after shifting the temperature to 37 degrees C. The MBP-MOMP competitively inhibited the infectivity of viable chlamydiae for epithelial cells, indicating that the MOMP and intact chlamydiae bind the same host receptor. Heparan sulfate markedly reduced binding of the MBP-MOMP to cells, whereas chondroitin sulfate had no effect on binding. Enzymatic treatment of cells with heparitinase but not chondroitinase inhibited the binding of MBP-MOMP. These same treatments were also shown to reduce the infectivity of chlamydiae for epithelial cells. Mutant cell lines defective in heparan sulfate synthesis but not chondroitin sulfate synthesis showed a marked reduction in the binding of MBP-MOMP and were also less susceptible to infection by chlamydiae. Collectively, these findings provide strong evidence that the MOMP functions as a chlamydial cytoadhesin and that heparan sulfate proteoglycans are the host-cell receptors to which the MOMP binds.
Collapse
Affiliation(s)
- H Su
- Laboratory of Intracellular Parasites, National Institute of Allergy and Infectious Diseases, Rocky Mountain Laboratory, Hamilton, MT 59840, USA
| | | | | | | | | | | |
Collapse
|
45
|
Abstract
The chlamydiae are obligate intracellular parasites that develop and multiply within a vacuole (termed an inclusion) that does not fuse with lysosomes. Inclusion morphology varies dramatically among the different chlamydiae, particularly within the species Chlamydia psittaci. Some strains develop within a single vacuole, while the mature inclusion of other strains consists of several distinct lobes, each filled with chlamydial developmental forms. The development of this lobed structure was investigated in HeLa cells infected with the guinea pig inclusion conjunctivitis (GPIC) strain of C. psittaci. We employed two recently described probes for the chlamydial inclusion to study the development of these unique lobed structures. The novel probes were an antiserum directed at a protein localized to the GPIC inclusion membrane (anti-IncA) and the fluorescent sphingolipid (N-[7-(4-nitrobenzo-2-oxa-1,3-)]) aminocaproyl sphingosine (NBD-ceramide). Lobed inclusions developed in cells infected at very low multiplicities of infection, suggesting that the structure is not a function of infection by more than one elementary body (EB). Double-label fluorescent-antibody analysis with anti-IncA and an antibody directed at a chlamydial outer membrane protein showed that, prior to 18 h postinfection (p.i.), the inclusion membrane and the chlamydial membrane were tightly associated. After 18 to 20 h p.i., the lobes began to expand and fill with developmental forms and the inclusion membrane and chlamydial membrane became distinct. At times from 8 to 48 h p.i., GPIC inclusions were shown to receive fluorescent derivatives of NBD-ceramide and to be localized to the perinuclear region of the host cell. Labeled lectins with affinity for carbohydrate moieties localized to the Golgi apparatus showed that the lobes of mature inclusions surround the Golgi apparatus. Labeling with NBD-ceramide and the Golgi apparatus-specific lectins therefore demonstrated a functional and physical association of the inclusion with the Golgi apparatus throughout the developmental cycle. Collectively, these results lead to a model for the development of the lobed chlamydial inclusion. We propose that the lobed structure is a result of division of inclusions occurring in parallel with the multiplication of reticulate bodies (RB) early in the developmental cycle. The division of inclusions slows or stops in mid-cycle, and dividing RB accumulate within the enlarging lobes. The RB then differentiate to EBs, the inclusion and cell are lysed, and EBs are freed to infect another cell.
Collapse
Affiliation(s)
- D D Rockey
- Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840, USA.
| | | | | |
Collapse
|
46
|
Abstract
Coxiella burnetii undergoes a poorly defined developmental cycle within phagolysosomes of eukaryotic host cells. Two distinct developmental forms are part of this cycle: a small-cell variant (SCV) and large-cell variant (LCV). Ultrastructurally, the SCV is distinguished from the LCV by its smaller size and condensed chromatin. At a molecular level, little is known about morphogenesis in C. burnetii, and no proteins specific to the SCV have been identified. Preparative isoelectric focusing was conducted to purify basic proteins possibly involved in SCV chromatin structure. A predominant protein of low M(r) was present in the most basic fraction, eluting with a pH of approx. 11. Degenerate deoxyoligonucleotides corresponding to the N-terminal sequence of this protein were used to recover a cosmid clone from a C. burnetii genomic library. Nucleotide sequencing of insert DNA revealed an open reading frame designated scvA (Small-Cell-variant protein A) with coding potential for a 30 amino acid protein (ScvA) with a predicted M(r) of 3610. ScvA is 46% arginine plus 46% glutamine with a predicted pl of 12.6. SDS-PAGE and silver staining of lysates of SCV and LCV purified by caesium chloride-equilibrium density centrifugation revealed a number of proteins unique to each cell type. Immunoblot analysis with ScvA antiserum demonstrated the presence of ScvA only in the SCV. By Immunoelectron microscopy, ScvA antiserum labelled only the SCV, with the label concentrated on the condensed nucleoid. In addition, ScvA bound double-stranded DNA in gel mobility-shift assays. A 66% reduction in the mean number of gold particles per Coxiella call was observed at 12 h post-infection when compared with the starting inoculum. Collectively, these data suggest that synthesis of ScvA is developmentally regulated, and that the protein may serve a structural or functional role as an integral component of the SCV chromatin. Moreover, degradation of this protein may be a necessary prerequisite for morphogenesis from SCV to LCV.
Collapse
Affiliation(s)
- R A Heinzen
- Laboratory of Intracellular Parasites, National Institute of Allergy and Infectious Disease, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, Montana, USA.
| | | | | | | | | |
Collapse
|
47
|
Rockey DD, Chesebro BB, Heinzen RA, Hackstadt T. A 28 kDa major immunogen of Chlamydia psittaci shares identity with Mip proteins of Legionella spp. and Chlamydia trachomatis-cloning and characterization of the C. psittaci mip-like gene. Microbiology (Reading) 1996; 142 ( Pt 4):945-953. [PMID: 8936321 DOI: 10.1099/00221287-142-4-945] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Chlamydia psittaci strain guinea-pig inclusion conjunctivitis (GPIC) produces a self-limiting ocular infection of guinea-pigs, and this condition is a representative animal model of ocular chlamydial disease. Convalescent guinea-pigs, which are resistant to reinfection, produce antibodies to several elementary-body proteins, including an uncharacterized antigen of 28 kDa. Convalescent guinea-pig sera were used to identify, from a lambda expression library, two overlapping GPIC genomic clones that produced the 28 kDa antigenic protein. Nucleotide sequence analysis revealed that the gene coding for the 28 kDa protein was similar to the mip (macrophage infectivity potentiator) genes from Legionella pneumophila and Chlamydia trachomatis. The GPIC gene and its product were accordingly designated mip and Mip, respectively. Analysis of the regions flanking mip identified three tightly linked open reading frames coding for predicted products with sequence similarity to asparagine tRNA ligase (AspS), rRNA methylase (SpoU), and thioredoxin (TrxA). The arrangement of these genes in GPIC was aspS-mip-spoU-trxA. Sequence analysis of PCR products produced using genomic DNA from an ovine abortion strain of C. psittaci and from C. trachomatis strain LGV-434 demonstrated that the arrangement of mip, spoU and trxA is common among these chlamydiae.
Collapse
Affiliation(s)
- Daniel D Rockey
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA
| | - Brian B Chesebro
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA
| | - Robert A Heinzen
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA
| | - Ted Hackstadt
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA
| |
Collapse
|
48
|
Heinzen RA, Scidmore MA, Rockey DD, Hackstadt T. Differential interaction with endocytic and exocytic pathways distinguish parasitophorous vacuoles of Coxiella burnetii and Chlamydia trachomatis. Infect Immun 1996; 64:796-809. [PMID: 8641784 PMCID: PMC173840 DOI: 10.1128/iai.64.3.796-809.1996] [Citation(s) in RCA: 302] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Coxiella burnetii and Chlamydia trachomatis are bacterial obligate intracellular parasites that occupy distinct vacuolar niches within eucaryotic host cells. We have employed immunofluorescence, cytochemistry, fluorescent vital stains, and fluid-phase markers in conjunction with electron, confocal, and conventional microscopy to characterize the vacuolar environments of these pathogens. The acidic nature of the C. burnetii-containing vacuole was confirmed by its acquisition of the acidotropic base acridine orange (AO). The presence of the vacuolar-type (H+) ATPase (V-ATPase) within the Coxiella vacuolar membrane was demonstrated by indirect immunofluorescence, and growth of C. burnetii was inhibited by bafilomycin A1 (Baf A), a specific inhibitor of the V-ATPase. In contrast, AO did not accumulate in C. trachomatis inclusions nor was the V-ATPase found in the inclusion membrane. Moreover, chlamydial growth was not inhibited by Baf A or the lysosomotropic amines methylamine, ammonium chloride, and chloroquine. Vacuoles harboring C. burnetii incorporated the fluorescent fluid- phase markers, fluorescein isothiocyanate-dextran (FITC-dex) and Lucifer yellow (LY), indicating trafficking between that vacuole and the endocytic pathway. Neither FITC-dex nor LY was sequestered by chlamydial inclusions. The late endosomal-prelysosomal marker cation-independent mannose 6-phosphate receptor was not detectable in the vacuolar membranes encompassing either parasite. However, the lysosomal enzymes acid phosphatase and cathepsin D and the lysosomal glycoproteins LAMP-1 and LAMP-2 localized to the C. burnetii vacuole but not the chlamydial vacuole. Interaction of C. trachomatis inclusions with the Golgi-derived vesicles was demonstrated by the transport of sphingomyelin, endogenously synthesized from C6-NBD-ceramide, to the chlamydial inclusion and incorporation into the bacterial cell wall. Similar trafficking of C-NBD-ceramide was not evident in C. burnetii-infected cells. Collectively, the data indicate that C. trachomatis replicates within a nonacidified vacuole that is disconnected from endosome-lysosome trafficking but may receive lipid from exocytic vesicles derived from the trans-Golgi network. These observations are in sharp contrast to those for C. burnetii, which by all criteria resides in a typical phagolysosome.
Collapse
Affiliation(s)
- R A Heinzen
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840-2999,USA
| | | | | | | |
Collapse
|
49
|
Hackstadt T, Rockey DD, Heinzen RA, Scidmore MA. Chlamydia trachomatis interrupts an exocytic pathway to acquire endogenously synthesized sphingomyelin in transit from the Golgi apparatus to the plasma membrane. EMBO J 1996; 15:964-77. [PMID: 8605892 PMCID: PMC449991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Chlamydia trachomatis acquires C6-NBD-sphingomyelin endogenously synthesized from C6-NBD-ceramide and transported to the vesicle (inclusion) in which they multiply. Here we explore the mechanisms of this unusual trafficking and further characterize the association of the chlamydial inclusion with the Golgi apparatus. Endocytosed chlamydiae are trafficked to the Golgi region and begin to acquire sphingolipids from the host within a few hours following infection. The transport of NBD-sphingolipid to the inclusion is energy- and temperature-dependent with the characteristics of an active, vesicle-mediated process. Photo-oxidation of C5-DMB-ceramide, in the presence of diaminobenzidine, identified DMB-lipids in vesicles in the process of fusing to the chlamydial inclusion membrane. C6-NBD-sphingomyelin incorporated into the plasma membrane is not trafficked to the inclusion to a significant degree, suggesting the pathway for sphingomyelin trafficking is direct from the Golgi apparatus to the chlamydial inclusion. Lectins and antibody probes for Golgi-specific glycoproteins demonstrate the close association of the chlamydial inclusion with the Golgi apparatus but do not detect these markers in the inclusion membrane. Collectively, the data are consistent with a model in which C.trachomatis inhabits a unique vesicle which interrupts an exocytic pathway to intercept host sphingolipids in transit from the Golgi apparatus to the plasma membrane.
Collapse
Affiliation(s)
- T Hackstadt
- Laboratory of Intracellular Parasites, Rock Mountain Laboratories, NIAID, NIH, Hamilton, MT 59840, USA
| | | | | | | |
Collapse
|
50
|
Hackstadt T, Scidmore MA, Rockey DD. Lipid metabolism in Chlamydia trachomatis-infected cells: directed trafficking of Golgi-derived sphingolipids to the chlamydial inclusion. Proc Natl Acad Sci U S A 1995; 92:4877-81. [PMID: 7761416 PMCID: PMC41810 DOI: 10.1073/pnas.92.11.4877] [Citation(s) in RCA: 265] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Chlamydia trachomatis undergoes its entire life cycle within an uncharacterized intracellular vesicle that does not fuse with lysosomes. We used a fluorescent Golgi-specific probe, (N-[7-(4-nitrobenzo-2-oxa-1,3-diazole)]) aminocaproylsphingosine (C6-NBD-Cer), in conjunction with conventional fluorescence or confocal microscopy to identify interactions between the Golgi apparatus and the chlamydial inclusion. We observed not only a close physical association between the Golgi apparatus and the chlamydial inclusion but the eventual presence of a metabolite of this fluorescent probe associated with the chlamydiae themselves. Sphingomyelin, endogenously synthesized from C6-NBD-Cer, was specifically transported to the inclusion and incorporated into the cell wall of the intracellular chlamydiae. Incorporation of the fluorescent sphingolipid by chlamydiae was inhibited by brefeldin A. Chlamydiae therefore occupy a vesicle distal to the Golgi apparatus that receives anterograde vesicular traffic from the Golgi normally bound for the plasma membrane. Collectively, the data suggest that the chlamydial inclusion may represent a unique compartment within the trans-Golgi network.
Collapse
Affiliation(s)
- T Hackstadt
- Host-Parasite Interactions Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, MT 59840, USA
| | | | | |
Collapse
|